JP2003107788A - Image forming method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method which prevents the degradation in primary electrostatic chargeability by residual toners of transfer remaining on a photoreceptor after transfer and prevents image defects, such as fogging and low density, by slow rising of the triboelectrostatic charge quantity of the toners and is excellent in image reproducibility in long term use and an image forming device. SOLUTION: The image forming method using an amorphous silicon photoreceptor having a conductive base and a photoconductive layer composed of a non-crystalline material essentially consisting of silicone atom and disposed on the conductive base and the toners having at least a binder resin, coloring agents and tin oxide particulates, in which the tin oxide particulates contain a tungsten element and/or phosphorus element of 0.1 to 30 mol% of the tin element and the image forming device are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner and an amorphous silicon system for visualizing an electrostatic latent image in an image forming method such as an electrophotographic method, an electrostatic recording method, a magnetic recording method and a toner jet method. The present invention relates to an image forming method and an image forming apparatus using a photoconductor.

[0002]

2. Description of the Related Art Conventionally, as an image forming method, many methods such as an electrostatic recording method, a magnetic recording method and a toner jet method are known. For example, in electrophotography, an electric latent image is generally formed on an image bearing member such as a photoconductor using a photoconductive material by various means, and then the latent image is developed with toner. The image is obtained by forming a visible image, transferring the toner image to a recording medium such as paper, if necessary, and fixing the toner image on the recording medium by heat, pressure or the like.

Generally, various materials such as selenium, cadmium sulfide, zinc oxide, amorphous materials such as amorphous silicon (hereinafter referred to as a-Si), or organic materials are used as materials for the light receiving member used in the electrophotographic photoreceptor. Materials have been proposed. Among these, an amorphous deposited film containing silicon atoms as a main component represented by a-Si, for example, hydrogen containing hydrogen and / or halogen (eg, fluorine, chlorine, etc.) or a- for compensating for dangling bonds Amorphous deposited films of Si and the like have been proposed as high performance (high resolution), high durability, pollution-free photoconductors, and some of them have been put to practical use. JP-A-54-86341, USP 4,265,99
No. 1 discloses a technique of an electrophotographic photoreceptor in which a photoconductive layer is mainly formed of a-Si. In addition, JP-A-60-
Japanese Patent No. 12554 discloses a photoconductor having a surface layer containing carbon and halogen atoms on the surface of a photoconductive layer made of amorphous silicon containing silicon atoms. , A-Si: H or a-
A photoreceptor having a surface protective lubricating layer provided on a C: H photosensitive layer is disclosed.

Further, in the image formation, after the transfer, the toner remaining on the image bearing member without being transferred to the recording medium is cleaned by various methods and stored as waste toner in a waste toner container. An image forming method in which the above steps are repeated is used.

For this cleaning step, conventionally blade cleaning, fur brush cleaning, roller cleaning, etc. have been used. In either method, the residual toner after transfer is mechanically scraped off or dammed and collected in a waste toner container. From the viewpoint of the apparatus, the cleaning apparatus using the fur brush and roller cleaning necessarily inevitably requires a large apparatus for equipping these members, and therefore blade cleaning is preferably used from the viewpoint of downsizing the apparatus. However, when such a member is pressed against the surface of the image bearing member, the image bearing member is not worn and shortened in life, and it is never completely cleaned. Contamination such as transfer residual toner passing through the cleaning blade is not caused. There is a problem that the primary charging member is contaminated with the substance and the charging potential is lowered. Particularly when an amorphous silicon photoconductor is used, the amount of abrasion of the photoconductor is small due to the high hardness of the surface layer, so that the photoconductor is often used in a machine having high durability and high speed, and the cleaning property is deteriorated. The problem is noticeable.

Further, in order to solve the above-mentioned problems relating to cleaning, and further to save resources, reduce waste, and effectively utilize toner, a cleaning device is removed to develop a system without waste toner. A system called simultaneous cleaning, or cleanerless, is desired.

However, the disclosure of the conventional technique related to simultaneous cleaning at the same time as development or cleanerless is disclosed in Japanese Patent Laid-Open Publication No. Hei 5 (1993) -53.
As described in Japanese Patent No. 2287, the focus is mainly on a positive memory, a negative memory and the like due to the influence of transfer residual toner on the image. However, with the increasing use of electrophotography, there is a need to transfer a toner image to various recording media, and in this sense, it is not satisfactory for various recording media.

[0008] Japanese Patent Application Laid-Open No. 59-133573, Japanese Patent Application Laid-Open No. 62-203182, and Japanese Patent Application Laid-Open No. 63-133179 are disclosed in the disclosure of the technology relating to cleanerless.
Japanese Patent Laid-Open No. 64-20587, Japanese Patent Laid-Open No. 2-3
No. 02772, Japanese Patent Application Laid-Open No. 5-2289, Japanese Patent Application Laid-Open No. 5-53482, Japanese Patent Application Laid-Open No. 5-61383, etc., but the detailed and specific configuration of the entire system is not mentioned.

Various methods are also known for the developing step of forming a visible image with toner. For example, as a method of visualizing an electric latent image, a cascade developing method, a pressure developing method, a magnetic brush developing method using a two-component developer composed of a carrier and a toner, and the like are known. A non-contact one-component developing method in which the toner carrier flies from the toner carrier to the image carrier in a non-contact manner with the image carrier. There is also used a magnetic one-component developing method in which an electric field is flown between the upper portions, and a contact one-component developing method in which a toner carrier is pressed against an image carrier to transfer toner by an electric field.

Conventionally, in the simultaneous development cleaning which essentially does not have a cleaning device, it has been essential to rub the surface of the image bearing member with the toner and the toner bearing member. Therefore, as a developing method preferably applied to the cleanerless, Many contact development methods have been studied in which toner or toner contacts an image bearing member. This is because, in order to collect the transfer residual toner in the developing device, the toner or the toner is considered to be in contact with the image carrier and rubbed, which is considered to be advantageous. However, in the simultaneous development cleaning or cleanerless process to which the contact development method is applied, there is an adverse effect that toner deterioration, toner carrier surface deterioration, image carrier surface deterioration or abrasion is likely to occur due to long-term use. Therefore, a simultaneous development cleaning method using a non-contact developing method is desired.

Further, in the image forming method used in the electrophotographic apparatus, the electrostatic recording apparatus, etc., there are various methods for forming a latent image on an image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric. It has been known.

For example, in the electrophotographic method, a photosensitive member using a photoconductive material as an image carrier is uniformly charged to a required polarity and potential, and then exposed to an image pattern to form an electrical latent image. The method of forming an image is common.

Conventionally, a corona charger (corona discharger) has often been used as a charging device for uniformly charging (including static elimination) the image carrier to a required polarity and potential. The corona charger is a non-contact type charging device, which is equipped with a discharge electrode such as a wire electrode and a shield electrode surrounding the discharge electrode, and the discharge opening is arranged in a non-contact manner so as to face the image carrier, which is the member to be charged. The surface of the image carrier is exposed to a discharge current (corona shower) generated by applying a high voltage to the discharge electrode and the shield electrode so that the surface of the image carrier is charged in a predetermined manner.

In recent years, as a charging device for a charged member such as an image carrier, a contact charging device has been proposed and put into practical use because it has advantages such as low ozone and low power as compared with a corona charger. There is.

The contact charging device is a roller type (charging roller), a fur brush type, a magnetic brush type, a blade type, or other electrically conductive charging member (contact charging member / contact charger), which is charged to an image carrier or the like. The charging member is brought into contact with the body and a predetermined charging bias is applied to the charging member to charge the surface of the body to be charged to a predetermined polarity and potential.

Contact charging mechanism (charging mechanism,
In the charging principle), two types of charging mechanisms, a discharge charging mechanism and a direct injection charging mechanism, coexist, and each characteristic appears depending on which one is dominant. Discharge Charging Mechanism This mechanism charges the surface of the body to be charged by a discharge phenomenon that occurs in the minute gap between the contact charging member and the body to be charged. Since the discharge charging mechanism has a constant discharge threshold between the contact charging member and the body to be charged, it is necessary to apply a voltage higher than the charging potential to the contact charging member. Further, compared with a corona charger, the generation amount is remarkably small, but generation of a discharge product is unavoidable in principle, so that a harmful effect due to active ions such as ozone is unavoidable. In particular, when using an amorphous silicon type photoconductor, the hardness of the surface layer is much higher than that of an organic type photoconductor, which makes it very difficult to mechanically remove the discharge products attached to the photoconductor surface. Therefore, the discharge product adsorbs moisture, and the resistance of the surface of the photoconductor is lowered, so that the outline of the image is not clear due to the flow of the latent image potential, and a blurred image or a flow image tends to occur. As a measure to prevent such image defects,
A measure to prevent a defective image by heating an amorphous silicon-based photoconductor and removing moisture adsorbed on a discharge product has been taken and implemented. Direct injection charging mechanism In this system, the surface of the body to be charged is charged by directly injecting charge from the contact charging member into the body to be charged. It is also called direct charging, injection charging, or charge injection charging. More specifically, a medium-resistance contact charging member comes into contact with the surface of the member to be charged and directly injects the charge into the surface of the member to be charged without a discharge phenomenon, that is, basically without using discharge. Therefore, even if the applied voltage to the contact charging member is equal to or lower than the discharge threshold value, the charged body can be charged to a potential corresponding to the applied voltage. Since this charging system does not generate ions, no harm is caused by the discharge products. However, since it is the direct injection charging, the contact property of the contact charging member to the member to be charged greatly affects the charging property. Therefore, in order to contact the body to be charged more frequently, the contact charging member preferably has a denser contact point, has a large speed difference from the body to be charged, or the like.

In the contact charging device, a roller charging method using a charging roller as a contact charging member is preferable from the viewpoint of charging stability and is widely used.

The above-mentioned discharge charging mechanism is dominant in the charging mechanism in the conventional roller charging.

The charging roller is made of a conductive or medium-resistance rubber material or foam. Further, there is also one in which these are laminated to obtain desired characteristics.

The charging roller has elasticity in order to obtain a constant contact state with the body to be charged, and therefore has a large friction resistance, and in many cases, is driven by the body to be charged or driven with a slight speed difference. It However, even in such a contact charging device, since the essential charging mechanism uses the discharge phenomenon from the contact charging member to the photosensitive member, as described above, the voltage applied to the contact charging member is a photosensitive member. A value higher than the body surface potential is required, a certain amount of ozone is generated, and the above-described image defects are likely to occur.

Further, when AC charging is performed to make the charging uniform, further ozone is generated, vibration noise (AC charging sound) between the contact charging member and the photoconductor due to the electric field of AC voltage, and discharge are generated. Deterioration of the surface of the photoconductor becomes remarkable, which is a new problem.

Therefore, charging by direct injection charging which is not discharge is preferable, but in the case of the conventional roller type charging member,
Even if the injection charging is attempted, the absolute charging ability is deteriorated, the contact property is insufficient, the contact unevenness due to the roller shape, and the charging unevenness due to the adhered matter on the charged body are likely to occur.

Further, in the injection charging by the fur brush, although the contact point with the photosensitive member is increased and the injection charging property is improved as compared with the conventional roller type charging member, the absolute charging ability and the charging unevenness are low, and the charging is not performed. Image defects due to uniformity are likely to occur.

On the other hand, the magnetic brush charging uses a member (magnetic brush charger) having a magnetic brush portion formed into a brush shape by magnetically restraining conductive magnetic particles with a magnet roll or the like as a contact charging member. By using a conductive magnetic particle having a particle size of 5 to 50 μm as a constituent of the brush portion and providing a sufficient speed difference with the photosensitive member and bringing the photosensitive member into contact with the photosensitive member, the contact point with the photosensitive member is more than that of a charging member using a fur brush. Is much improved, and even if charging is performed by injection, uniform charging is possible, and the occurrence of image defects due to that is not caused.

However, the device structure is complicated, the device tends to be large-sized, and the conductive magnetic particles forming the magnetic brush portion may drop off and adhere to the photoconductor.

Now, consider the case where these contact charging methods are applied to the simultaneous cleaning method for development and the cleanerless image forming method.

In the simultaneous developing method and the cleanerless image forming method, the transfer residual toner remaining on the photoconductor because it does not have a cleaning member directly contacts the contact charging member and adheres or is mixed therein. Further, in the case of a charging method in which the discharge charging mechanism is dominant, deterioration of toner adhesion due to discharge energy also causes deterioration of adhesion to the charging member. When the commonly used insulating toner adheres to or mixes with the contact charging member, the charging property is deteriorated.

In the case of the charging method in which the discharge charging mechanism is predominant, the decrease in the chargeability of the member to be charged rapidly occurs when the toner layer adhering to the surface of the contact charging member becomes a resistance that obstructs the discharge voltage. Happen to.

On the other hand, in the case of the charging method in which the direct injection charging mechanism is dominant, the transfer residual toner adhered or mixed reduces the contact probability between the surface of the contact charging member and the member to be charged. The chargeability of the body is reduced.

The decrease in the uniform charging property of the member to be charged results in a decrease in the contrast and uniformity of the electrostatic latent image after image exposure, which increases the width of unevenness in image density or increases fog.

Further, in the simultaneous development cleaning method and the cleanerless image forming method, the charge polarity and the charge amount of the transfer residual toner on the photoconductor are controlled to stably recover the transfer residual toner in the developing process, and the recovered toner is The point is not to deteriorate the development characteristics, and the charge polarity and charge amount of the transfer residual toner is controlled during the charging step.

This will be specifically described by taking a general laser printer as an example.

In the case of reversal development using a charging member for applying a negative polarity voltage, a negatively charging photosensitive member and a negatively charging toner, an image visualized by the positive polarity transfer member is recorded on a recording medium in the transfer step. Although it is transferred, the charging polarity of the transfer residual toner varies from plus to minus depending on the relationship between the type of recording medium (difference in thickness, resistance value, dielectric constant, etc.) and image area.
However, due to the negative polarity charging member when charging the negatively chargeable photoconductor, even the transfer residual toner along with the surface of the photoconductor is uniformly moved to the negative side even if it is swung to the positive polarity in the transfer process. If the charging polarities can be made uniform, when reversal development is used as the developing method, negatively charged transfer residual toner remains in the bright portion potential portion of the toner to be developed, and the toner is developed. Due to the developing electric field, the dark portion potential that should not be drawn is attracted toward the toner carrier, and the transfer residual toner is collected without remaining on the photoconductor having the dark portion potential. That is, by simultaneously controlling the charging polarity of the transfer residual toner by the charging member at the same time as the charging of the photosensitive member, the simultaneous cleaning of development,
A cleanerless image forming method is established.

However, if the transfer residual toner adheres to or mixes with the contact charging member beyond the control capability of the toner charging polarity of the contact charging member, it is not possible to uniformly arrange the transfer residual toner with the charging polarity, and depending on the developing member. It becomes difficult to collect the toner. Even if the toner on the toner carrier is recovered by a mechanical force such as rubbing, if the transfer residual toner is not evenly charged, the chargeability of the toner on the toner carrier will be adversely affected and the development characteristics Lower.

That is, in the simultaneous development cleaning and cleanerless image forming method, the charge control characteristics of the transfer residual toner when passing through the charging member and the adhesion / mixing characteristics to the charging member are closely related to the durability characteristics and the image quality characteristics. Connected to.

Japanese Patent Publication No. 7-99442 discloses a structure in which a contact charging member is coated with powder on the contact surface with the surface of the member to be charged in order to improve the charging property of the photosensitive member and to perform stable and uniform charging. There is. However, since the contact charging member (charging roller) is driven to rotate (no speed difference drive) with respect to the member to be charged (photoreceptor), the generation of ozone products is significantly reduced compared to corona chargers such as scorotron. However, as in the case of the roller charging described above, the charging principle still mainly uses the discharge charging mechanism. Particularly, in order to obtain more stable charging uniformity, a voltage in which an AC voltage is superimposed on a DC voltage is applied, so that the ozone products are more generated by the discharge. Therefore, when the device is used for a long period of time, adverse effects such as image deletion due to ozone products are likely to appear. Further, when applied to a cleanerless image forming apparatus, it becomes difficult for the applied powder to uniformly adhere to the charging member due to the mixture of the transfer residual toner, and the effect of uniform charging is diminished.

Further, in JP-A-5-150539, in the image forming method using contact charging, toner particles and silica fine particles which cannot be completely cleaned by blade cleaning during repeated image formation on the surface of the charging means. It is disclosed that the toner contains at least developer particles and conductive particles having an average particle size smaller than that of the developer particles in order to prevent charging inhibition due to adhesion and accumulation. However, the contact charging or the proximity charging used here is based on the discharge charging mechanism and not the direct injection charging mechanism, but has the above-mentioned problems due to the discharge charging. Further, when applied to a cleaner-less image forming apparatus, as compared with a case where a cleaning mechanism is provided, a large amount of conductive fine particles and transfer residual toner affect the charging property due to passing through the charging process. No consideration is given to the recoverability of the conductive fine particles and the transfer residual toner in the developing process, and the influence of the recovered conductive fine particles and the transfer residual toner on the development characteristics of the toner. Further, when the direct injection charging mechanism is applied to the contact charging, the conductive fine particles are not supplied to the contact charging member in the required amount, and the charging failure occurs due to the influence of the transfer residual toner.

Further, in the simultaneous development image forming method, JP-A-11-15206 discloses that the simultaneous cleaning development performance is improved by improving the charge control characteristic of the transfer residual toner when passing through the charging member. ,
An image forming method using a toner having toner particles containing a specific carbon black and a specific azo-based iron compound and an inorganic fine powder has been proposed. Further, in the simultaneous development image forming method, it has been proposed to improve the simultaneous cleaning performance by decreasing the amount of transfer residual toner by using a toner having a transfer coefficient that defines the shape factor of the toner and having excellent transfer efficiency. However, the contact charging used here is also due to the discharge charging mechanism, and not the direct injection charging mechanism, but the above-mentioned problems due to discharge charging. Further, although these proposals have the effect of suppressing the decrease in the charging uniformity of the photoconductor due to the transfer residual toner of the contact charging member, the effect of positively increasing the charging property cannot be expected.

Further, some commercially available electrophotographic printers use a roller member that comes into contact with the photosensitive member between the transfer step and the charging step, and assist or control the recovery property of the residual toner after the development. There is also an image forming apparatus. Although such an image forming apparatus exhibits good cleaning ability at the same time of development and can greatly reduce the amount of waste toner,
The cost is high, and the advantage of simultaneous cleaning during development is lost in terms of size reduction.

In contrast to these, Japanese Patent Laid-Open No. 10-307456
Japanese Patent Application Laid-Open Publication No. 2003-242977, wherein a toner containing toner particles and electrically conductive charge-promoting particles having a particle diameter of ½ or less of the toner particle diameter is applied to a simultaneous development developing image forming method using a direct injection charging mechanism. A device is disclosed. According to this proposal, without generating discharge products,
An image forming apparatus for simultaneous cleaning with development, which can reduce the amount of waste toner to a large extent and is advantageous in cost reduction and downsizing, can be obtained, and a good image can be obtained without causing charging failure, light blocking of image exposure, or diffusion.

Further, in Japanese Patent Laid-Open No. 10-307421, a toner containing conductive particles having a particle diameter of 1/50 to 1/2 of the toner particle diameter is directly injected into a toner image by using a direct injection charging mechanism. There is disclosed an image forming apparatus which is applied to a forming method and has conductive particles having a transfer promoting effect.

Further, in Japanese Patent Laid-Open No. 10-307455, the particle size of the fine particles is set to be equal to or smaller than the size of one pixel of the constituent pixels, and the particle size of the fine particles is set to 10 nm to 50 μm in order to obtain better charging uniformity. It is described to do.
In Japanese Patent Laid-Open No. 10-307457, the conductive particles are set to about 5 μm or less, preferably 20 nm to 5 μm in order to make it difficult to visually recognize the influence of a poorly charged portion on an image in consideration of human visual characteristics. It is described to do.

Further, according to Japanese Patent Application Laid-Open No. 10-307458, by setting the particle size of the fine particles to be equal to or smaller than the toner particle size,
The development of the toner is hindered during development, or the development bias is prevented from leaking through the fine particles to eliminate image defects, and the particle size of the fine particles is set to 0.1.
There is described a simultaneous cleaning image forming method for development using a direct injection charging mechanism which solves the problem of blocking the exposure light by embedding fine particles in the image carrier by setting it larger than μm. .

According to Japanese Patent Laid-Open No. 10-307456, fine particles are externally added to the toner, and the fine particles contained in the toner are developed at least at the contact portion between the flexible contact charging member and the image carrier. Simultaneous development cleaning that can adhere to the image carrier in the process, remain on the image carrier even after the transfer process, and be carried and intervened, resulting in good images that do not cause charging failure and light blocking of image exposure. An image forming apparatus is disclosed.

Further, there has been proposed a technique for stabilizing the triboelectrification property by incorporating the above-mentioned fine particles having relatively low resistance and a metal oxide. For example, JP-A-6-17539
No. 2, the volume resistance value is 1 × 10 ⁵ to 1 × 10 ⁸ Ωc.
A known metal oxide of m (alumina, zinc oxide, tin oxide, etc.) is added to the binder resin constituting the toner. Alternatively, a technique of externally adding low resistance particles such as a reduced product of a metal oxide, antimony-containing tin oxide, carbon black powder, and metal particles to a toner is disclosed (Japanese Patent Publication No. 07-113781). 06-11869
3 gazette).

Certainly, according to these proposals, the simultaneous cleaning image forming method for development can be achieved, and the cleanerless system becomes possible.

Known metal oxides such as alumina, zinc oxide, and tin oxide exhibit a resistance value of about 1 × 10 ⁶ to 1 × 10 ⁷ Ωcm under the environment of normal temperature and humidity due to the influence of hydroxyl groups on the surface. There are many. However, the resistance value depends on humidity, and the resistance constantly fluctuates, so the physical properties are not stable even when it is included in the toner, and especially the triboelectric charge amount of the toner does not rise quickly, and fog and low density images occur. I have something to do.

Since tin oxide containing antimony can easily exhibit conductivity by firing in an air atmosphere, resistance variation due to humidity can be prevented, but the fired product exhibits a blue to black blue color. When externally added to the toner, tin oxide released from the toner in the image forming step is transferred to the transfer paper, which causes deterioration in image quality due to color.
Further, addition to the color toner also causes a decrease in color reproducibility.

Oxides which exhibit conductivity by firing a metal oxide such as tin oxide or titanium oxide in a reducing atmosphere such as hydrogen gas to reduce a part of the tin component, or carbon black are Due to the reduction treatment, the fired product becomes blackish and causes the color reproducibility of the toner and the deterioration of the image quality as in the case of tin oxide containing antimony.

The above problem occurs as a particularly remarkable problem in the case of a cleanerless image forming method.

Furthermore, low resistance materials such as metal particles are
Since it may cause a leak phenomenon in a developing process requiring a high electric field, it lacks long-term stability.

In particular, when the photoconductor is an amorphous silicon type photoconductor, it is often used in a machine having high durability and high speed because the amount of abrasion of the photoconductor is small due to the high hardness of its surface layer. The triboelectric charge amount of the toner, which is an agent, needs to rise rapidly on the toner carrier, and in the case of an image forming method without a cleaner, it is necessary to quickly control the triboelectric charge amount of the transfer residual toner even during the charging step. is there.

[0053]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a decrease in primary charging property due to transfer residual toner when an amorphous silicon type photosensitive member is used, and to increase the triboelectric charge amount of a toner as a developer. To provide an image forming method and an image forming apparatus which prevent image defects such as fogging and low density due to slowness, and have excellent image reproducibility even in use environment and long time use.

Further, an object of the present invention is to provide an image forming method and an image forming apparatus capable of forming a cleanerless image by combining stable primary charging property and developing simultaneous cleaning property even if an amorphous silicon type photosensitive member is used. To provide.

[0055]

SUMMARY OF THE INVENTION According to the present invention, a charging step of applying a voltage to a charging member to charge an image bearing member, and an electrostatic latent image forming an electrostatic latent image on the charged image bearing member. An image forming step, a toner carried on a toner carrier, a developing step of transferring the toner to the electrostatic latent image held on the surface of the image carrier to form a toner image, and a developing step formed on the image carrier. An image forming method including at least a transfer step of electrostatically transferring the toner image onto a transfer material,
An amorphous silicon-based photoconductor having a conductive support and a photoconductive layer formed on the conductive support and made of an amorphous material containing silicon atoms as a main component. It has a resin, a colorant, and tin oxide fine particles, and the tin oxide fine particles have a tin content of 0.
The image forming method is characterized by containing 1 to 30 mol% of a tungsten element and / or a phosphorus element.

In the present invention, the image carrier, charging means for applying a voltage to the charging member to charge the image carrier, and electrostatic means for forming an electrostatic latent image on the charged image carrier. A latent image forming unit, a developing unit for transferring the toner carried on the toner carrier to the electrostatic latent image held on the surface of the image carrier to form a toner image, and a developing unit for developing the toner image on the image carrier. In an image forming apparatus including at least a transfer unit for electrostatically transferring the formed toner image onto a transfer material, the image carrier includes a conductive support and a silicon atom provided on the conductive support. An amorphous silicon-based photoreceptor having a photoconductive layer composed of an amorphous material as a main component, wherein the toner has at least a binder resin, a colorant and tin oxide fine particles, and the tin oxide fine particles are 0.1 to 30 for tin element ol% of tungsten element and /
Alternatively, the image forming apparatus is characterized by containing a phosphorus element.

[0057]

DETAILED DESCRIPTION OF THE INVENTION An image forming method and an image forming apparatus of the present invention will be described.

In the image forming method and the image forming apparatus of the present invention, an amorphous silicon type photosensitive member is used as a member to be charged, and at least a binder resin and a colorant are included as a toner. It is characterized in that a toner further containing tin oxide fine particles containing 30 mol% of a tungsten element and / or a phosphorus element is used. The image forming method of the present invention has the advantage that an image having high durability and high image quality can be obtained by using an amorphous silicon-based photoconductor as the member to be charged. Further, as the charging step, by using the step of charging the image bearing member by forming a contact portion with the image bearing member and applying a voltage to the charging member, as described above, there are many advantages such as low ozone and low power consumption. Is obtained.

<1> Toner of the Present Invention The toner of the present invention contains at least a binder resin, a colorant, and tin oxide fine particles, and the tin oxide fine particles contain 0.1 to 30 mol% of tungsten with respect to the tin element. It is characterized by containing an element and / or a phosphorus element.

By using a toner in which tin oxide fine particles containing 0.1 to 30 mol% of tungsten element and / or phosphorus element with respect to tin element are used, a white system is achieved and the color tone of the toner is hindered. It is possible to prevent the factors of image quality deterioration without having to do so, and at the same time, since the effect of preventing hygroscopicity is high, the humidity dependency of resistance is suppressed, so even when the environment changes, a stable resistance value and triboelectric charging ability, It is possible to show a rapid rise of the charge amount. Due to such an action, the toner containing fine particles of tin oxide in the present invention can quickly and sharply adjust the distribution of triboelectric charge amount, and uniform triboelectric charge property can be obtained for a long period of time. In particular, under low humidity, charge-up due to abnormal triboelectric charging is prevented, and under high humidity, the triboelectric charge amount is prevented from lowering due to moisture absorption of the toner, and stable triboelectric chargeability can be imparted. Therefore, a good image can be obtained. Further, even in the case of the cleanerless case, the charge amount rises quickly, so that it becomes possible to control the transfer residual toner during the charging process.

In the present invention, it is more preferable that the tin oxide fine particles mixed in the toner contain a tungsten element, and the effect obtained by using the toner having the tin oxide fine particles containing a tungsten element is It has the function of preventing wear of the body, has the ability to withstand long-term use under high voltage because it has excellent voltage resistance to voltage, and has the function of preventing wear of the developing sleeve as a toner carrier. It may be excellent and may maintain high image quality for a long time. That is, in general, the photoconductor wear often progresses non-uniformly, and the image density may become non-uniform in the initial stage of the wear or image fog may occur when the wear progresses. Since it is possible to prevent such wear that causes deterioration of image quality, high image quality is maintained for a long period of time.

The tungsten element, phosphorus element and tin element in the toner can be qualitatively and quantitatively determined by ICP, ESCA or the like. Specifically, the content of each element is converted to mol by an inductively coupled plasma emission spectroscopic analyzer (IPC-AES), and mol% is calculated.

In Japanese Patent Laid-Open No. 9-278445,
A technique relating to a conductive tin oxide material using tungsten as a dopant is disclosed. However, the basic concept of using conductive tin oxide in the publication relates to a moldable conductive polymer material obtained by dispersing conductive tin oxide in an organic polymer, and the coating composition has a resistance as a conductive coating film. The basic concept is that the value has excellent stability over time. On the other hand, the present invention specifies the conditions such as the presence ratio and the particle size ratio, in particular, on the surface of the toner particles while being entangled with various materials (for example, toner particles, photoconductor, surface of charging member, etc.). In this way, the triboelectric charge amount generated by the contact between the tin oxide fine particles and the toner particles is modified, and a new effect is exhibited as a developer.
Since the invention relates to an electrophotographic system that is realized by controlling the behavior of tin oxide particles in a special usage pattern that utilizes the functions of the tin oxide particles themselves, they are completely different inventions including not only the fields of use but also the ideas leading to the technology. Is.

Further, Japanese Unexamined Patent Publication No. 6-183733 discloses a technique relating to a conductive tin oxide material in which antimony and tungsten are used together as a dopant. Since the above tin oxide particles use antimony together, the effect (whiteness,
The basic concept of using conductive tin oxide in this publication also relates to a moldable conductive polymer material obtained by dispersing conductive tin oxide in an organic polymer. As described above, the two are completely different inventions including not only the field of use but also the idea of reaching the technology.

Furthermore, JP-A-6-92636, 1
Japanese Patent Application Laid-Open No. 0-53417 discloses a technique relating to a conductive tin oxide material using phosphorus as a dopant, but the basic concept is that the resistance value of the powder itself is excellent over time. As described above, the two are completely different inventions including not only the field of use but also the idea of reaching the technology.

If the content of tungsten and / or phosphorus element is 0.1 mol% or less, the resistance tends to be high,
Contamination to primary charging is likely to occur. Tungsten and /
Or, when the content of the element of phosphorus element is 30 mol% or more,
The doping effect on tin oxide is weakened, the characteristics of the elemental tungsten and / or elemental phosphorus are likely to be exhibited, and the resistance is likely to be high. Therefore, contamination of primary charging is likely to occur, which is not preferable.

In the present invention, the method of incorporating the tin oxide fine particles into the toner includes internal addition and external addition. In order to carry out the above-described effects of the present invention more quickly and efficiently, it is preferable that the tin oxide fine particles are present on the surface of the toner particles, and as a means for achieving this, external addition that is easy to control is preferable. Other than these, means for exposing the surface by a mechanical method such as grinding or polishing after the internal addition is also included.

The resistance value of the tin oxide fine particles is 1 × 1.
It is preferably 0 ² Ωcm or more and less than 1 × 10 ⁹ Ωcm. When the resistance value of the tin oxide fine particles is larger than 1 × 10 ⁹ Ωcm, when the tin oxide fine particles are applied to the image forming method using the simultaneous cleaning with development, the tin oxide fine particles may be present in the contact portion between the charging member and the image carrier or in the vicinity thereof. In order to obtain good chargeability, the charge injection property to the photoconductor is lowered even if the close contact property of the contact charging member to the image carrier is maintained through the tin oxide fine particles of the contact charging member. This is not preferable because it is difficult to obtain the effect of promoting charging. Furthermore, in order to sufficiently bring out the charge accelerating effect of the tin oxide fine particles and to stably obtain good chargeability, the resistance value of the tin oxide fine particles is set to the value of the surface portion of the contact charging member or the contact portion with the image carrier. It is preferably smaller than the resistance.

As a method of controlling the resistance within the above range,
Acid value of the metal of tin oxide (the tin valence of tin oxide is 4)
It becomes possible to control by adding an appropriate amount of a different element having a selected valence. That is, the different element preferably used for tin oxide, which is a tetravalent metal oxide, preferably has a valence of 5, and tungsten and phosphorus are preferably used as such different element.

By including tungsten and / or phosphorus in the tin oxide fine particles, the effect of lowering the resistance was recognized, and the effect of suppressing the resistance fluctuation due to the environment was also observed. Particularly, the effect of increasing the resistance in a low humidity environment was obtained. It was confirmed that there is.

When the resistance value is less than 1 × 10 ² Ωcm,
When the photoconductor has a pinhole, the electric charge is concentrated on that portion, the charging member and the photoconductor are destroyed, and the image is liable to come off in the lateral direction.

The resistance value of the tin oxide fine particles is measured as follows. Cell B shown in FIG. 4 is filled with 0.5 g of tin oxide fine particles left in a measurement environment for 24 hours or more, electrodes 21 and 22 are arranged so as to be in contact with the tin oxide fine particles, and a voltage is applied between the electrodes to flow at that time. Obtained by measuring the current. The measurement conditions were as follows: the contact area between the tin oxide particles and the electrode was 2.26 cm ² in an environment of 23 ° C. and 65%, and 15
A pressure is applied with a load of kg, the height of the cell is measured with a caliper, the current is measured with an applied voltage of 50 V, and the volume resistance value is calculated from the area and the height.

As the particle diameter of the tin oxide fine particles, it is preferable to use one having a volume average particle diameter smaller than the volume average particle diameter of the toner particles in the toner, specifically, the volume average particle diameter of 0.05 μm or more. It is preferable to use one.

In the image forming method using a cleaner, the smaller the particle size of the tin oxide fine particles present in the portion where the photoconductor and the charging member are in contact with each other, the larger the number of contact points and the higher the charging uniformity. Particle size is 0.05 μm
If it is less than, in order to behave in synchronization with the toner particles,
Most of the tin oxide fine particles migrate to the transfer material together with the toner particles during the transfer process, so the supply of tin oxide fine particles to the charging process section becomes insufficient, and the charging uniformity tends to decrease, which is not preferable. .

When the average particle diameter of the tin oxide fine particles is small, the content of the tin oxide fine particles in the whole toner must be set small in order to prevent deterioration of the developing property under high humidity. Volume average particle size of tin oxide particles is 0.05
If it is less than μm, an effective amount of fine particles of tin oxide cannot be secured,
In the case of a cleanerless image forming method, in the charging process, adhesion of insulating transfer residual toner to the contact charging member
A sufficient amount of tin oxide fine particles can be intervened in the contact area between the charging member and the image carrier or in the vicinity of the charging area to overcome the charge inhibition due to the mixture and to charge the image carrier well. Therefore, charging failure is likely to occur. More preferably, it is 0.1 μm or more.

When the volume average particle diameter of the tin oxide fine particles is larger than the volume average particle diameter of the toner particles, the tin oxide particles are easily separated from the toner particles when mixed with the toner particles, and are supplied from the developing container to the image carrier in the developing step. The amount is insufficient, and it is difficult to obtain sufficient chargeability. Further, the tin oxide fine particles that have fallen off the charging member block or diffuse the exposure light for writing the electrostatic latent image, thereby causing defects in the electrostatic latent image and degrading the image quality. Furthermore, if the average particle size of the tin oxide fine particles is large, the tin oxide particles are easily released from the charging member, and the number of particles per unit weight is reduced. In consideration of tin oxide particles, in order to continuously supply tin oxide particles to the contact area between the charging member and the image carrier or to the charging area in the vicinity thereof, the contact charging member intervenes through the tin oxide particles. In order to maintain close contact with the image carrier and to stably obtain good chargeability, the content of tin oxide fine particles in the entire toner must be increased.

However, if the content of the tin oxide fine particles is too large, the triboelectrification ability and the developability are deteriorated especially in a high humidity environment, and the image density is lowered and the toner is easily scattered. From this point of view, the tin oxide fine particles have a volume average particle size of 5
μm or less is preferable. Considering the wear of the image carrier, 5μ
More preferably, the number% of particles of m or more is 3% or less. The volume average particle size and particle size distribution of the tin oxide particles in the present invention are measured in a measurement range of 0.04 to 2000 μm by attaching a liquid module to a LS-230 type laser diffraction particle size distribution measuring device manufactured by Coulter. As a measuring method, a trace amount of a surfactant is added to 10 ml of pure water, 10 mg of a tin oxide fine particle sample is added thereto, and the mixture is dispersed for 10 minutes using an ultrasonic disperser (ultrasonic homogenizer), and then a measurement time of 90 The measurement is performed once per second.

Further, the measurement from the toner was 100 g of pure water.
To the toner 2 to 10
g is added and dispersed for 10 minutes using an ultrasonic disperser (ultrasonic homogenizer), and then the toner particles are separated from the tin oxide fine particles by a centrifugal separator or the like. In the case of magnetic toner, a magnet may be used to separate the toner particles and the tin oxide fine particles. Measurement time for the separated dispersion liquid 9
The measurement is performed at 0 seconds and once.

The particle size when the tin oxide fine particles are formed as an agglomerate is defined as the average particle size of the agglomerate. There is no problem that the tin oxide fine particles exist not only in the state of primary particles but also in the state of agglomeration of secondary particles. Whatever the aggregated state, any form may be used as long as it is present as an aggregate in the contact area between the charging member and the image carrier or in the charging area in the vicinity thereof to realize the function of assisting or promoting charging.

Furthermore, the liberation rate of tin oxide fine particles is 5 to 9
It is preferably 0%. When the liberation rate of tin oxide fine particles is less than 5%, the amount supplied to the image bearing member is insufficient and it is difficult to obtain sufficient chargeability, and when it is more than 90%, the amount of fine particles recovered by simultaneous cleaning with development is small. This is not preferable because the amount of toner particles increases and the triboelectric chargeability and developability of the toner deteriorate due to the accumulation of fine particles in the developing device.

The liberation rate of tin oxide fine particles is represented by the ratio of the number of tin atoms in tin oxide not contained in the toner particles to the sum of the number of carbon atoms contained in the toner particles and tin atoms in the tin oxide. . The release rate is 65 to 65 in the Japan Hardcopy 97 papers.
It can be measured by the principle described on page 68. Specifically, the toner particles are introduced into the plasma one by one, and from the obtained emission spectrum, the elements in the toner particles, the number of toner particles, and the particle size of the toner particles are known. The release rate can be measured from this emission spectrum.

According to the above-mentioned measuring method, the liberation rate of tin oxide can be calculated from the emission of carbon atoms which are the constituent elements of the binder resin contained in the toner particles and the emission of tin atoms by the following formula.

[Equation 1]

In the above formula, "simultaneous light emission" means
2.6ms from the emission of carbon atoms from the emission of tin atoms
The light emission is within ec, and the light emission from the tin atom thereafter is the light emission from only the tin atom. The simultaneous emission of carbon atoms and tin atoms means that they are synchronized with the toner particles, and the emission of only tin atoms means that tin (tin oxide) is released from the toner particles. .

The liberation rate can be measured by using a particle analyzer (PT1000: Yokogawa Electric Co., Ltd.) that utilizes an emission spectrum. The specific measuring method is as follows. First, using helium gas containing 0.1% oxygen, measurement is performed in an environment of 23 ° C. and a humidity of 60%,
The toner sample is left in the same environment overnight to adjust the humidity.
When measuring, channel 1 uses carbon atoms (measurement wavelength 2
47.860 nm, K factor uses recommended value), channel 2 tin atom (measurement wavelength 326.23 nm, K factor is not set) is measured, and the number of emission of carbon atom is 1000 to 1400 in one scan. Sampling is performed so that the number of times of emission is equal to the number of times, and scanning is repeated until the total number of times of emission of carbon atoms reaches 10,000 or more, and the number of times of emission is integrated. At this time, in the distribution in which the number of times of emission of carbon atoms is plotted on the vertical axis and the cube root voltage of carbon atoms is plotted on the horizontal axis, the distribution has one maximum and further, a distribution in which no valley exists Sampling and measurement. And
Based on this data, the noise cut level of all atoms is 1.
The release rate of tin oxide is calculated using the above formula with 50 V. In addition, the same measurement is performed in Examples described later.

Further, it is preferable that the tin oxide fine particles are transparent, white or light-colored fine particles because the fine particles transferred onto the transfer material are not noticeable as fog. The tin oxide fine particles are preferably transparent, white or light tin oxide fine particles also in the sense that they do not interfere with the exposure light in the electrostatic latent image forming step, and more preferably, the tin oxide fine particles have a transmittance for the exposure light of 30. % Or more is preferable.

In the present invention, the light transmittance of the tin oxide fine particles is measured by the following procedure. The transmittance is measured with one layer of tin oxide fine particles fixed on a transparent film having an adhesive layer on one surface. The light is emitted from the vertical direction of the sheet, and the light transmitted to the back surface of the film is condensed to measure the light amount. The transmittance of the particles is calculated as the net amount of light from the amount of light when only the film and the tin oxide fine particles are attached. Actually, it is measured using a 310T transmission densitometer manufactured by X-Rite.

The tin oxide fine particles present on the toner particle surface are preferably in a proportion of 0.3 or more per toner particle, and more preferably 1.0 or more and 50.0 or less per toner particle. Is. If it is less than 0.3, the effect of improving the fluidity of the toner may be deteriorated, which is not preferable.

The presence or absence of the tin oxide fine particles present on the surface of the toner particles and the proportion thereof can be obtained by directly observing the surface of the toner particles. That is, a toner containing fine particles of tin oxide is captured by an electron microscope (SEM) with 10 toner particles as one aggregate, and is present on the surface of each toner particle.
Alternatively, the number of individual fine particles having a peak indicating the presence of phosphorus element is counted.

For the qualitative analysis of the elements, a qualitative analysis apparatus attached to the SEM is used. By this method, measurement is performed on 10 aggregates (total of 100 toner particles), and the existence ratio of tin oxide fine particles per 100 toner particles is calculated. Particles having peaks indicating the presence of tin element and tungsten element and / or phosphorus element can be analyzed by prior composition analysis (for example, IC
P, ESCA, etc.) to confirm that the oxide is tin oxide (SnO ₂ ) containing a tungsten element and a phosphorus element, and take appropriate measures.

Further, the toner in the present invention is preferably a toner containing tin oxide fine particles in an amount of 0.2 to 10% by mass based on the whole toner. If the content of tin oxide fine particles in the total toner is less than 0.2% by mass, in the case of a cleanerless image forming method, charging inhibition due to adhesion / mixing of the insulating transfer residual toner to the contact charging member is overcome. As a result, tin oxide fine particles in an amount sufficient to charge the image bearing member satisfactorily cannot be interposed in the contact area between the charging member and the image bearing member or in the charging area in the vicinity thereof.
The chargeability is lowered and charging failure is likely to occur. On the other hand, if the content is more than 10% by mass, the amount of tin oxide fine particles collected by simultaneous cleaning at the time of development may be too large, which may reduce the chargeability and developability of the toner in the developing section, resulting in a decrease in image density and toner. Easy to be scattered. further,
The content of tin oxide fine particles in the entire toner is 1.5.
It is preferable that the content is ˜5% by mass.

The tin oxide fine particles may be added externally or internally as described above, and the toner of the present invention contains at least a binder resin and a colorant in addition to the tin oxide fine particles.

As the colorant used in the toner, conventionally known dyes and / or pigments can be used. As the colorant, for example, carbon black, phthalocyanine blue, peacock blue, permanent red,
Rake Red, Rhodamine Rake, Hansar Yellow,
Examples include permanent yellow and benzidine yellow. The content of the colorant is 0.1 to 20 parts by mass, preferably 0.5 to 20 parts by mass, with respect to 100 parts by mass of the binder resin, and to improve the transparency of the OHP film having the toner image fixed thereon. Is preferably 12 parts by mass or less, more preferably 0.5 to 9 parts by mass.

The binder resin used in the toner of the present invention has a glass transition temperature of preferably 45 to 80 ° C., more preferably 55 to 70 ° C., and a number average molecular weight (Mn) in the molecular weight distribution measured by GPC. Is 1,500 ~
50,000, weight average molecular weight (Mw) of 6,000-
A binder resin of 1,000,000 is preferred.

The glass transition point (Tg) of the binder resin is measured under the following conditions using a differential thermal analyzer (DSC measuring device) and DSC-7 (manufactured by Perkin Elmer). Sample: 5 to 20 mg, preferably 10 mg Temperature curve: Temperature increase I (20 ° C. → 180 ° C., temperature increase rate 10 ° C./min.) Temperature decrease I (180 ° C. → 10 ° C., temperature decrease rate 10 ° C./min.) Temperature increase II (10 ° C. → 180 ° C., temperature rising rate 10 ° C./min.) Tg measured in temperature rising II is used as a measured value. Measurement method: Put the sample in an aluminum pan and use an empty aluminum pan as a reference. The crossing point between the line at the midpoint of the base line before and after the appearance of the endothermic peak and the differential heat curve is defined as the glass transition point Tg.

In the present invention, the endothermic main peak temperature at the time of temperature rise is preferably 60 to 140 ° C. in the DSC curve measured by a differential scanning calorimeter (DSC) of the toner.
Is more preferable, and more preferably in the range of 60 to 120 ° C. in the toner having a specific particle size distribution in the present invention. Further, it is preferable that the exothermic main peak temperature at the time of cooling is in the range of 60 to 150 ° C, and more preferably in the range of 60 to 130 ° C.

For the DSC measurement, for example, DSC-7 manufactured by Perkin Elmer can be used. The amount of sample used for measurement is about 10 to 15 mg in the case of a toner sample.
I have The measuring method is performed according to ASTM D3418-82. As the DSC curve used in the present invention, the DSC curve measured when the temperature is raised once and the previous history is taken, and then the temperature is lowered and raised in the temperature range of 0 ° C./min to 200 ° C. is used.

Further, the molecular weight measured by GPC is
The solution dissolved in HF (tetrahydroxyfuran) by allowing it to stand at room temperature for 24 hours is filtered through a solvent-resistant membrane filter having a pore size of 0.2 μm to obtain a sample solution, which can be measured, for example, under the following conditions. . In the sample preparation, the amount of THF is adjusted so that the concentration of the THF-soluble component is 0.4 to 0.6% by mass.

Device: High-speed GPC HLC8120 GP
C (manufactured by Tosoh Corporation) Column: Shodex KF-801, 802, 80
7, 804, 805, 806, and 807 (Showa Denko KK) Eluent: THF Flow rate: 1.0 ml / min Oven temperature: 40.0 ° C. Sample injection amount: 0.10 ml

In calculating the molecular weight of the sample,
Standard polystyrene resin (TSK standard polystyrene F-850, F-450, F-28 manufactured by Tosoh Corporation)
8, F-128, F-80, F-40, F-20, F-
10, F-4, F-2, F-1, A-5000, A-2
500, A-1000, A-500) can be used.

The molecular weight of the toner can be arbitrarily changed depending on the binder resin used and the kneading conditions when the toner is produced by the pulverization method. Further, in the polymerization method, depending on the combination of the polymerization initiator used, the type and amount of the crosslinking agent,
It can be changed arbitrarily. It can also be adjusted by using a chain transfer agent or the like.

Examples of the binder resin used in the toner of the present invention include homopolymers of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and their substitution products; styrene-p-chlorostyrene copolymerization. Copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethacryl copolymer, styrene-acrylonitrile copolymer Polymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer Styrene copolymers such as polymers Coalescing; polyvinyl chloride, phenol resins, natural resin modified phenol resins, natural resin modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyester resins, polyurethane, polyamide resins, furan resins, epoxy resins,
Xylene resin, polyvinyl butyral, terpene resin,
Examples include coumarone indene resin and petroleum-based resin.

Examples of the comonomer for the styrene monomer of the styrene copolymer include vinyl monomers. Examples of vinyl monomers include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate. , Ethyl methacrylate,
Monocarboxylic acids having double bonds such as butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. or substituted products thereof; for example, maleic acid, butyl maleate, methyl maleate, dimethyl maleate, etc. A dicarboxylic acid having a bond and a substituted product thereof; for example, vinyl ester such as vinyl chloride, vinyl acetate, vinyl benzoate; for example, vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone; for example, vinyl methyl ether, vinyl ethyl Vinyl ethers such as ether and vinyl isobutyl ether; These are used alone or in combination of two or more.

The binder resin used in the present invention may be a polymer or copolymer crosslinked with a crosslinking monomer. Examples of the crosslinkable monomer include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate. Diacrylate compounds linked by an alkyl chain such as acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate; and those in which the acrylate of the above compounds is replaced by methacrylate; diethylene glycol diacrylate, triethylene glycol diacrylate Acrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate,
Diacrylate compounds linked by an alkyl chain containing an ether bond such as polyethylene glycol # 600 diacrylate and dipropylene glycol diacrylate; and those in which the acrylate of the above compounds is replaced by methacrylate; polyoxyethylene (2)- 2,2-bis (4-hydroxyphenyl) propane diacrylate,
Diacrylate compounds linked by a chain containing an aromatic group and an ether bond such as polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate; and acrylate of the above compounds to methacrylate Substituted products; polyester type diacrylates such as trade name MANDA (Nippon Kayaku Co., Ltd.);

Further, pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylates and acrylates of the above compounds are replaced by methacrylates; triallyl cyanurate, triaryl cyanurate Allyl trimellitate etc. are also mentioned as a crosslinkable monomer.

These crosslinkable monomers are preferably 0.01 to 10 relative to 100 parts by mass of the other monomer components.
Parts by mass, more preferably 0.03 to 5 parts by mass can be used. Of these crosslinkable monomers, fixability,
From the standpoint of offset resistance, it is preferably used as
Examples thereof include aromatic divinyl compounds (particularly divinylbenzene), diacrylate compounds linked by a chain containing an aromatic group and an ether bond.

As the binder resin used in the present invention, the polyester resins shown below are also preferable. It is preferable that 45 to 55 mol% of all polyester components are alcohol components and 55 to 45 mol% are acid components.

As the alcohol component, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol,
Polyhydric alcohols such as 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl 1,3-hexanediol, hydrogenated bisphenol A, bisphenol derivatives, diols, glycerin, sorbit and sorbitan Is mentioned.

Examples of the acid component include divalent carboxylic acids, such as phthalic acid, terephthalic acid, isophthalic acid,
Benzenedicarboxylic acids such as phthalic anhydride or anhydrides thereof; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or anhydrides thereof, and further substituted with an alkyl or alkenyl group having 6 to 18 carbon atoms Octosuccinic acid or its anhydride; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid, and their anhydrides; and carboxylic acids having a valence of 3 or more, trimellitic acid, Pyromellitic acid,
Examples thereof include benzophenone tetracarboxylic acid and its anhydride.

A bisphenol derivative is particularly preferable as the alcohol component of the polyester resin, and phthalic acid, terephthalic acid, isophthalic acid or an anhydride thereof, succinic acid, n-dodecenylsuccinic acid or an anhydride thereof, fumaric acid, or And dicarboxylic acids such as maleic acid and maleic anhydride; and trimellitic acid or its tricarboxylic acid anhydride. A toner using a polyester resin obtained from these acid component and alcohol component as a binder resin has good fixability and excellent offset resistance.

The acid value of the polyester resin is preferably 90 mgKOH / g or less, more preferably 50 mgKO.
It is H / g or less. The OH value of the polyester resin is preferably 50 mgKOH / g or less, more preferably 30.
It is below mgKOH / g. This is because as the number of terminal groups of the molecular chain increases, the charging characteristic of the toner becomes more environmentally dependent.

The glass transition temperature (T
g) is preferably 50 to 75 ° C., more preferably 55.
~ 65 ℃ is good, GP of polyester resin
In the molecular weight distribution measured by C, the number average molecular weight (M
n) is preferably 1,500 to 50,000, more preferably 2,000 to 20,000, and the weight average molecular weight (Mw) is preferably 6,000 to 100,000,
It is more preferably 10,000 to 90,000.

The toner of the present invention preferably has a weight average particle diameter of 3 to 10 μm in order to faithfully develop fine latent image dots for higher image quality. A toner having a weight average particle diameter of less than 3 μm has a large amount of transfer residual toner on the image bearing member due to a decrease in toner transfer efficiency, and easily contaminates the charging member when used in the contact charging step.
There is a tendency that the charging promotion effect of the tin oxide fine particles is reduced. Further, in addition to the increase in the surface area of the toner as a whole, the fluidity and agitation property of the powder are lowered, and it becomes difficult to uniformly triboelectrically charge the individual toner particles. However, it is not preferable as the toner used in the image forming method of the present invention because it easily causes image defects due to factors other than the charging property.
Further, when the weight average particle diameter of the toner exceeds 10 μm, scatter easily occurs in characters and line images, and it is difficult to obtain high resolution. Further, as the resolution of the device becomes higher, the reproduction of one dot tends to deteriorate.

The volume average particle diameter of the toner is preferably 3 to 10 μm for the same reason as above.

The method of adjusting the average particle diameter of the toner can be adjusted by performing a classification operation using a wind force or a sieve with different openings.

The weight average particle diameter and volume average particle diameter of the toner of the present invention can be measured by various methods such as Coulter counter TA-II type or Coulter Multisizer (manufactured by Coulter Co.). Specifically, it can be measured as follows. Using a Coulter Multisizer (manufactured by Coulter), an interface (manufactured by Nikkaki) that outputs the number distribution and volume distribution and a PC9801 personal computer (manufactured by NEC) are connected, and the electrolyte is 1% NaCl using primary sodium chloride. Prepare the aqueous solution. For example, I
SOTON R-II (manufactured by Coulter Scientific Japan) can be used. The measurement procedure is as follows. 100-150 ml of the electrolytic aqueous solution is added, and 2-20 mg of a measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and then the Coulter Multisizer was used to use an aperture to
A volume distribution and a number distribution are calculated by measuring the volume and the number of the toner particles having a size of μm or more. Then, the volume-based weight average particle diameter (D4) obtained from the volume distribution according to the present invention.
And the volume average particle size.

The toner in the present invention may be either magnetic or non-magnetic toner, but more preferably a magnetic toner containing magnetic iron oxide. When the toner itself has a magnetic force, it is possible to suppress the scattering in the developing device by the magnet included in the toner carrier, and during the developing process,
The recoverability of the toner discharged from the charging member during the charging step is also improved by the magnetic force, which is preferable.

The magnetic field of the toner is 79.6 kA / m (1
000 Oersted) has a magnetization intensity of 10 to 50
Am ² / kg (emu / g) is preferable in order to reduce the amount of transfer residual toner and fog and maintain good chargeability.

When the toner of the present invention is used as a magnetic toner, the magnetic material contained in the toner includes iron oxides such as magnetite, maghemite and ferrite, and iron oxides containing other metal oxides; Fe and Co. , N
metals such as i, or these metals and Al, C
o, Cu, Pb, Mg, Ni, Sn, Zn, Sb, B
Examples thereof include alloys with metals such as e, Bi, Cd, Ca, Mn, Se, Ti, W and V, and mixtures thereof.

Specifically, as the magnetic material, tetra-trioxide is used.
Iron (Fe₃O_Four), Ferric oxide (γ-Fe)₂O₃),iron oxide
Zinc (ZnFe₂O_Four), Yttrium iron oxide (Y₃Fe_Five
O₁₂), Cadmium iron oxide (CdFe₂O_Four), Iron oxide
Dolinium (Gd₃Fe_FiveO₁₂), Iron oxide copper (CuFe₂
O_Four), Iron oxide lead (PbFe)₁₂O₁₉), Iron oxide nickel
(NiFe₂O_Four), Iron neodymium oxide (NdFe₂O₃),
Barium iron oxide (BaFe₁₂O₁₉), Iron oxide magnesium
Mu (MgFe₂O_Four), Iron manganese oxide (MnFe
₂O_Four), Lanthanum iron oxide (LaFeO₃), Iron powder (F
e), cobalt powder (Co) and nickel powder (Ni)
You can

The above magnetic materials may be used alone or in combination of two or more. A particularly suitable magnetic material is a fine powder of magnetic iron oxide such as ferric tetroxide or γ-iron sesquioxide.
Magnetic iron oxide is more preferable because it has an effect as a coloring agent.

The content of the magnetic material is 10 to 200 parts by mass, preferably 20 to 1 part by mass with respect to 100 parts by mass of the binder resin.
It is preferably 50 parts by mass.

The average circularity of the toner is preferably 0.970 or more. The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of particles, and in the present invention, measurement is carried out using a flow particle image analyzer "FPIA-1000" manufactured by Toa Medical Electronics. Done 3μ
The circularity (ai) of each particle measured with respect to a particle group having a circle equivalent diameter of m or more is determined by the following formula (1), and further the circularity of all particles measured as shown in the following formula (2). The value obtained by dividing the sum of the above by the total number of particles (m) is defined as the average circularity (a).

[0123]

[Equation 2]

[0124]

[Equation 3] In addition, the measuring device "FPIA-" used in the present invention is used.
1000 "means that after calculating the circularity of each particle, in calculating the average circularity, the particles are divided into 61 classes of 0.40 to 1.00 according to the circularity obtained, and the center of the division point is calculated. The calculation method of calculating the average circularity using the value and the frequency is used. However, the error with each value of the average circularity calculated by this calculation formula is very small and can be substantially ignored. In the present invention, the calculation time is shortened and the calculation formula is reduced. For the reason of handling data such as simplification, the above-described concept of the calculation formula that directly uses the circularity of each particle may be used and a partially modified calculation formula may be used.

The measuring means is as follows. 5 mg of toner is dispersed in 10 ml of water in which about 0.1 mg of the surfactant is dissolved to prepare a dispersion liquid, and ultrasonic waves (20 kH
z, 50 W) to the dispersion for 5 minutes to adjust the dispersion concentration to 5
The average circularity of particles having a circle-equivalent diameter of 3 μm or more is determined by measuring with 000 to 20,000 particles / μl.

The average circularity in the present invention is an index of the degree of unevenness of the toner, and it is 1.000 when the toner is a perfect sphere, and the more the surface shape becomes complicated, the smaller the circularity becomes.

The reason why the circularity is measured only for the particle group having the equivalent circle diameter of 3 μm or more in this measurement is 3 μm.
This is because the particle group having an equivalent circle diameter of less than m includes a large number of particles of the external additive that exist independently of the toner particles, and the circularity of the toner particle group cannot be accurately estimated due to the influence thereof. .

Further, in the present invention, the magnetization intensity of the magnetic toner is determined by using an oscillating magnetometer VSM P-1-10 (manufactured by Toei Industry Co., Ltd.) at room temperature of 25 ° C. and an external magnetic field of 79.6 k.
Measured in A / m.

In the toner of the present invention, it is preferable to use a charge control agent by blending (internally adding) the toner particles. The charge control agent makes it possible to control the optimum charge amount according to the developing method, and particularly in the present invention, it is possible to further stabilize the balance between the particle size distribution and the charge, and the charge control agent is used. As a result, it is possible to further clarify the function separation and the mutual complementarity for improving the image quality by the particle size range described above.

As the positive charge control agent, for example, a modified product of nigrosine and a fatty acid metal salt; a quaternary ammonium salt such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate and the like; They can be used alone or in combination of two or more. Among these, charge control agents such as nigrosine compounds and quaternary ammonium salts are particularly preferably used. Furthermore, a copolymer with a polymerizable monomer such as styrene, acrylic acid ester and methacrylic acid ester can be used as a positive charge control agent, and in this case, these charge control agents can be used as all or one of the binder resins. Part).

As the negative charge control agent, for example, organic metal complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids and aromatic dicarboxylic acid type metal complexes.
Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids, metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

The above charge control agent (which does not act as a binder resin) is preferably used in the form of fine particles. In this case, the number average particle diameter of the charge control agent is specifically 4 μm or less, preferably 3 μm or less. When internally added to the toner, such a charge control agent is used in an amount of 0.1 to 20 parts by mass (preferably 0.2 to 10 parts by mass) with respect to 100 parts by mass of the binder resin.

Examples of the releasing agent used in the toner of the present invention include petroleum waxes such as paraffin wax, microcrystalline wax and petrolactam and their derivatives, montan wax and its derivatives, hydrocarbon wax and its derivatives by the Fischer-Tropsch method,
Polyolefin wax represented by polyethylene and its derivatives, natural wax such as carnauba wax and candelilla wax and its derivatives, and the like include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, fatty acids such as higher aliphatic alcohols, stearic acid and palmitic acid, or compounds thereof, acid amide wax, ester wax, ketone,
Hydrogenated castor oil and its derivatives, vegetable waxes, animal waxes and the like having an endothermic peak in differential thermal analysis of 45 ° C. or higher and 110 ° C. or lower, more preferably 50 ° C. or higher and 90 ° C. or lower are preferable.

The content of the release agent is preferably in the range of 0.5 to 50% by mass based on the whole toner. If the content is less than 0.5% by mass, the low-temperature offset suppressing effect is poor, and if it exceeds 50% by mass, the long-term storability may deteriorate.

The endothermic peak of the release agent can be measured in the same manner as the endothermic peak of the binder resin.

In addition to the tin oxide fine particles described above, the toner according to the present invention has an average primary particle size of 4 as a fluidizing agent and a transfer aid.
It is preferable to add an inorganic fine powder of -80 nm. The inorganic fine powder is added to improve the fluidity of the toner, to make the triboelectric charge amount of the toner particles uniform and to improve the transfer property, but the triboelectric charge amount of the toner particles is treated by a treatment such as hydrophobicizing the inorganic fine powder. It is also a preferable mode to add functions such as adjustment of the above and improvement of environmental stability.

When the average primary particle size of the inorganic fine powder is larger than 80 nm, or when the inorganic fine powder having a particle size of 80 nm or less is not added, the transfer residual toner is increased and stable and good charging characteristics are obtained. Is difficult. Further, good fluidity of the toner is not obtained, charge impartment to the toner particles is likely to be non-uniform, and problems such as increased fog, reduced image density, and toner scattering cannot be avoided. When the average primary particle size of the inorganic fine powder is smaller than 4 nm, the inorganic fine powder has a stronger cohesive property, and is not a primary particle but an agglomerate having a wide particle size distribution with a strong cohesive property that is hard to be broken by crushing treatment. It tends to behave, and image defects are likely to occur due to development of aggregates, damage to the image bearing member or the toner bearing member, and the like. In order to make the triboelectric charge amount distribution of the toner particles more uniform, the average primary particle diameter of the inorganic fine powder is more preferably 6 to 70 nm.

In the present invention, the method for measuring the average primary particle size of the inorganic fine powder is a photograph of the toner magnified by a scanning electron microscope, and X attached to the scanning electron microscope.
100 or more primary particles of the inorganic fine powder existing on the surface of the toner particles adhering to or separated from the toner particles are measured while comparing the photograph of the toner mapped with the element contained in the inorganic fine powder by the elemental analysis means such as MA. Then, the number average particle diameter can be obtained.

As the inorganic fine powder used in the present invention,
Silica, alumina, titanium oxide, or their composite oxide can be used.

For example, as silica, so-called silicic acid fine powder.
Should be produced by vapor phase oxidation of silicon halides
Dry siri called so called dry method or fumed silica
So-called wet silica produced from mosquito, water glass, etc.
It is possible to use both
There are few silanol groups in the part, and Na₂O, SO₃ ^-
Preference is given to dry silica having less production residue such as. Also
In the case of dry silica, in the manufacturing process, for example, chloride
Other metal halogen compounds such as aluminum and titanium chloride
When used with a silicon halogen compound,
It is also possible to obtain complex fine powders of mosquito and other metal oxides.
It also includes them.

The addition amount of the inorganic fine powder having an average primary particle diameter of 4 to 80 nm is preferably 0.1 to 3.0% by mass with respect to the toner, and the addition amount is less than 0.1% by mass. The effect is not sufficient, and if it exceeds 3.0% by mass, the fixing property tends to deteriorate.

It is preferable that the inorganic fine powder is a hydrophobized product in view of the characteristics in a high temperature and high humidity environment. When the inorganic fine powder mixed with the toner particles absorbs moisture, the triboelectric charge amount of the toner is remarkably reduced, and toner scattering easily occurs.

Examples of the treatment agent for the hydrophobic treatment include silicone varnishes, various modified silicone varnishes, silicone oils, various modified silicone oils, silane compounds, silane coupling agents, and other treatment agents such as organic silicon compounds and organic titanium compounds. For example, they may be treated alone or in combination.

Among them, those treated with silicone oil are preferred, and more preferably those treated with silicone oil at the same time as or after the inorganic fine powder is subjected to hydrophobic treatment with a silane compound (hexamethyldisilazane etc.). Even in a high-humidity environment, the triboelectric charge amount of the toner can be maintained at a high level to prevent toner scattering.

The conditions for treating the inorganic fine powder include, for example, performing a silylation reaction with a silane compound as a first step reaction to eliminate silanol groups by a chemical bond, and then a second step reaction with silicone oil to make the surface hydrophobic. Can be formed into a thin film.

The above silicone oil preferably has a viscosity at 25 ° C. of 10 to 200,000 mm ² / s, more preferably 3,000 to 80,000 mm ² / s. If it is less than 10 mm ² / s, the inorganic fine powder is not stable, and the image quality tends to deteriorate due to heat and mechanical stress. If it exceeds 200,000 mm ² / s,
Uniform treatment tends to be difficult.

As the silicone oil used, for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like are particularly preferable. As a method of treating the silicone oil, as described above, for example, the inorganic fine powder treated with a silane compound and the silicone oil may be directly mixed using a mixer such as a Henschel mixer.
A method of spraying silicone oil on the inorganic fine powder may be used.

Alternatively, a method may be used in which after dissolving or dispersing silicone oil in an appropriate solvent, inorganic fine powder is added and mixed to remove the solvent. The method using a sprayer is more preferable in that the formation of aggregates of the inorganic fine powder is relatively small.

The amount of silicone oil to be treated is 1 for inorganic fine powder.
1 to 23 parts by weight, preferably 5 to 20 parts by weight with respect to 00 parts by weight
Good mass parts.

If the amount of silicone oil is too small, good hydrophobicity cannot be obtained, and if it is too large, problems such as fog tend to occur.

The average primary particle size used in the present invention is 4-8.
The 0 nm inorganic fine powder preferably has a specific surface area within the range of ²⁰ to 250 m ² / g due to nitrogen adsorption measured by the BET method.

The specific surface area is determined according to the BET method by using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics Co., Ltd.) to adsorb nitrogen gas on the sample surface, and calculating the specific surface area using the BET multipoint method. The toner of the present invention can be manufactured by a pulverization method or a polymerization method.

First, the pulverization method will be exemplified. When the binder resin, colorant, magnetic material, release agent, charge control agent, and tin oxide fine particles are internally added, the components necessary for toner such as tin oxide fine particles and other additives and other additives are added to the Henschel mixer. After sufficiently mixing with a mixer such as a ball mill, the mixture is melt-kneaded using a heat kneader such as a heating roll, kneader, or extruder, cooled and solidified, pulverized, classified, and surface-treated as necessary. Toner particles can be obtained. An external additive such as an inorganic fine powder or tin oxide fine particles is externally added to the obtained toner particles, and tin oxide fine particles are mixed to obtain a toner. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency. The crushing process can be performed by a method using a known crushing device such as a mechanical impact type and a jet type. Next, a suspension polymerization method will be exemplified as the polymerization method.

A polymerizable monomer serving as a binder resin and a colorant, and if necessary, a polymerization initiator, a crosslinking agent, a charge control agent, a release agent, a plasticizer, a magnetic material, and tin oxide fine particles are internally added. In the case, tin oxide fine particles and other additives are uniformly dissolved or dispersed by a homogenizer, a ball mill, a colloid mill, a disperser such as an ultrasonic disperser, or the like, and an aqueous medium containing a dispersion stabilizer. Suspend in. The polymerization initiator may be added at the same time as other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. It is also possible to add a polymerization initiator dissolved in a polymerizable monomer or a solvent immediately after granulation and before starting the polymerization reaction.

The polymerization temperature is 40 ° C. or higher, generally 50 to 9
Polymerization is carried out at a temperature of 0 ° C. When the polymerization is carried out within this temperature range, the release agent to be sealed inside is deposited by phase separation and the encapsulation becomes more complete. In order to consume the remaining polymerizable monomer, it is possible to raise the reaction temperature to 90 to 150 ° C. at the end of the polymerization reaction.

Examples of the polymerizable monomer constituting the polymerizable monomer system include the following.

Examples of the polymerizable monomer include styrene-based monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, methyl acrylate, and acrylic acid. Ethyl acetate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. Acrylic esters, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate,
Examples thereof include methacrylic acid esters such as 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and other monomers such as acrylonitrile, methacrylonitrile, and acrylamide.

These monomers may be used alone or in combination. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with other monomers, from the viewpoint of developing characteristics and durability of the toner.

A resin may be added to the polymerizable monomer system for polymerization. For example, since the monomer is water-soluble, it cannot be used because it dissolves in an aqueous suspension and causes emulsion polymerization, so it cannot be used as a hydrophilic functional group such as amino group, carboxylic acid group, hydroxyl group, sulfonic acid group, glycidyl group, and nitrile group. When it is desired to introduce the monomer component of the above into the toner, a random copolymer of these and a vinyl compound such as styrene or ethylene, a block copolymer, or a copolymer such as a graft copolymer is used, Alternatively, it can be used in the form of a polycondensate such as polyester or polyamide, or a polyaddition polymer such as polyether or polyimine. When such a polymer resin containing a polar functional group is allowed to coexist in the toner, the release agent is phase-separated, the inclusion becomes stronger, and the toner has good offset resistance, blocking resistance, and low-temperature fixability. Can be obtained. When such a polymer having a polar functional group is used, its average molecular weight is preferably 5,000 or more. When it is 5,000 or less, particularly 4,000 or less, the present polymer tends to concentrate near the surface, which is unfavorable since it tends to adversely affect the developability and blocking resistance. As the polar polymer, polyester resin is particularly preferable.

Further, a resin other than the above may be added to the monomer system for the purpose of improving the dispersibility and fixing property of the material, the image characteristics, etc. Examples of the resin used include polystyrene and polyvinyltoluene. Homopolymers of styrene and its substitutes; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-
Vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer Polymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Styrene-based copolymers such as coalesce; Methyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin, rosin, modified rosin, tempel resin, phenol resin, aliphatic or fat Aromatic hydrocarbon resins and aromatic petroleum resins can be used alone or in combination. The addition amount of these resins is 1
1 to 20 parts by mass is preferable with respect to 00 parts by mass. If it is less than 1 part by mass, the effect of addition is small, while if it is added in an amount of 20 parts by mass or more, it tends to be difficult to design various physical properties of the polymerized toner.

As the polymerization initiator, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile) is used. Nitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile,
Azo-based or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, t- Examples thereof include peroxide-based polymerization initiators such as butyl peroxy 2-ethylhexanoate.

A crosslinking agent may be added, and the preferable addition amount is 0.001 to 100 parts by mass of the binder resin.
It has 15 mass. As the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used. For example, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene; ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1 , 3-
A carboxylic acid ester having two double bonds such as butanediol dimethacrylate; a divinyl compound such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone; and a compound having three or more vinyl groups; Used as.

Examples of the dispersion stabilizer include a surfactant and an organic.
Inorganic dispersants can be used, and among them, inorganic dispersants are preferred from the viewpoint of dispersion stability. Examples of the inorganic dispersant include calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, and other polyvalent metal salts of phosphate, calcium carbonate, carbonates such as magnesium carbonate, inorganic salts such as calcium metasilicate, calcium sulfate, and barium sulfate. Examples thereof include inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite, and alumina. The inorganic dispersant is 0.2 to 20 with respect to 100 parts by mass of the polymerizable monomer.
Although it is desirable to use a mass part alone, it is difficult to generate ultrafine particles, but it is not enough to atomize the toner. Therefore, even if 0.001 to 0.1 part by mass of a surfactant is used together. good. Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.

<2> Image Forming Method of the Present Invention (a) Image Carrier In the image forming method of the present invention, the image carrier is a non-conductive material containing a conductive support and a silicon atom provided thereon as a main component. The use of an amorphous silicon-based photoconductor having a photoconductive layer made of a crystalline material has an advantage that an image with high durability and high image quality can be obtained.

Further, it is preferable that the surface layer of the photoconductor is an amorphous silicon type photoconductor in which an amorphous hydrogenated carbon film is formed. It is preferable to use an amorphous hydrogenated carbon film as the surface layer because the hardness is increased, the amount of wear due to durability is reduced, and high durability is achieved.

The "amorphous material containing silicon atoms as a main component" here mainly represents amorphous silicon, but it may partially contain fine crystals or polycrystals.

The film thickness of the surface layer used for the amorphous silicon type photoreceptor is 0.01 to 10 μm, preferably 0.1 μm from the relationship between the wear amount of the surface layer and the life of electrophotography.
The range of ˜1 μm is desirable. Surface layer thickness is 0.01μ
If it is m or less, mechanical strength is impaired, and if it is 10 μm or more, the residual potential becomes high, and it is difficult to obtain optimum potential setting and sensitivity.

The amorphous silicon-based photoconductor whose surface is composed of the amorphous hydrogenated carbon film preferably has a silicon atom content represented by the following formula (3) of 0.01% or less.

[0169]

## EQU00004 ## Silicon atom content rate (%) = (number of silicon atoms / (number of silicon atoms + number of carbon atoms)) × 100 (3) The silicon atom content (atom number) of the surface layer is measured by the carbon content. As a sample for measuring, a surface layer having a thickness of 0.5 μm deposited on a 7059 glass substrate was prepared, and the number of carbon atoms and silicon atoms was measured by SIMS for this surface layer sample, and C / (Si + C) was calculated. It is the calculated value.

The amount of hydrogen contained in the film of the surface layer composed of the amorphous hydrogenated carbon film is H / (C + H) of 41 to 60.
%, Preferably 45 to 55%. 40% hydrogen
If it is less than the above range, electrophotographic characteristics are deteriorated, it is difficult to secure a sufficient potential difference in the developing step, and image defects such as a fog image may occur, which is not preferable. On the other hand, if it exceeds 60%, the densification of the film and the mechanical strength are impaired, and the abrasion of the surface layer tends to increase, such being undesirable.

The above-mentioned amount of hydrogen was obtained by preparing a surface layer sample on a silicon wafer as a sample for measuring the hydrogen content of the surface layer, and comparing this surface layer sample with I
Measure the amount of hydrogen by R, H / (C + H) × 100
Calculate from (%).

Amorphous silicon type photoconductors (hereinafter referred to as "a-Si type photoconductors") used in the present invention will be described in detail below with reference to the drawings.

FIGS. 1A and 1B are examples of schematic sectional views of an a-Si type photosensitive member used in the present invention. In FIG. 1, (A) is a single-layer type a-Si-based photoreceptor in which the photoconductive layer is a single layer with no functional separation.
(B) is a function-separated a-Si-based photoreceptor in which the photoconductive layer is separated into a charge generation layer and a charge transport layer.

The a-Si type photosensitive member shown in FIG. 1A comprises a conductive support 101 such as aluminum and a conductive support 1.
01 is composed of a charge injection blocking layer 102, a photoconductive layer 103, and a surface layer 104, which are sequentially stacked. Here, the charge injection blocking layer 102 is formed from the conductive support 101 to the photoconductive layer 1.
It is to prevent the injection of electric charge into the switch 03, and is provided as necessary. The photoconductive layer 103 is made of an amorphous material containing at least silicon atoms and exhibits photoconductivity. Further, the surface layer 104 is made of an amorphous hydrogenated carbon film (aC: H film) containing carbon atoms and hydrogen atoms, and has the ability to hold a visible image in an electrophotographic apparatus.

In the a-Si type photoreceptor shown in FIG. 1B, the photoconductive layer 103 includes a charge transport layer 106 made of an amorphous material containing at least silicon atoms and carbon atoms, and at least silicon atoms. This is a function-separated type photoconductor in which a charge generation layer 105 made of an amorphous material is sequentially laminated. When this photoreceptor is irradiated with light, the carriers mainly generated in the charge generation layer 105 pass through the charge transport layer 106 and reach the conductive support 101.

FIG. 2 is a diagram schematically showing an example of a deposition apparatus for manufacturing an a-Si photosensitive member by the RF plasma CVD method using a high frequency power source.

This apparatus is roughly classified into a deposition apparatus 210.
0, a source gas supply device 2200, and an exhaust device (not shown) for reducing the pressure inside the reaction vessel 2110. The reaction vessel 2110 in the deposition apparatus 2100 has a cylindrical conductive support 2112 and a heater 2 for heating the support.
113, a source gas introduction pipe 2114 are installed, and a high frequency power supply 21 is further provided via a high frequency matching box 2115.
20 are connected.

The source gas supply device 2200 is composed of SiH ₄ ,
A cylinder 22 of a source gas such as H ₂ , CH ₄ , B ₂ H ₆ and CF ₄
21-2226 and valves 2231-2236, 2241
˜2246, 2251 to 2256 and mass flow controllers 2211 to 2216, and a cylinder of each source gas is a reaction vessel 2110 via a valve 2260.
It is connected to the gas introduction pipe 2114 inside.

The cylindrical conductive support 2112 is installed on the conductive pedestal 2123 to be connected to the ground.

An example of the procedure of the method for forming an a-Si photosensitive member using the apparatus shown in FIG. 2 will be described below.

A cylindrical conductive support 2112 is installed in the reaction vessel 2110, and the inside of the reaction vessel 2110 is evacuated by an exhaust device (not shown) such as a vacuum pump. Then, the temperature of the cylindrical conductive support 2112 is controlled to a desired temperature of 20 to 500 ° C. by the heater 2113 for heating the cylindrical conductive support. Next, in order to flow the raw material gas for forming the a-Si photosensitive member into the reaction vessel 2110, it is necessary to confirm that the valves 2231 to 2236 of the gas cylinder and the leak valve 2117 of the reaction vessel are closed. 2241 to 2246, outflow valves 2251 to 2256,
After confirming that the auxiliary valve 2260 is opened, the main valve 2118 is opened to exhaust the reaction vessel 2110 and the gas supply pipe 2116.

Thereafter, the vacuum system 2119 reads 0.67.
When the pressure reaches mPa, the auxiliary valve 2260 and the outflow valves 2251 to 2256 are closed. Then the gas cylinder 222
Each gas is introduced from 1 to 2226 by opening the valves 2231 to 2236, and each gas pressure is adjusted to ² kg / cm ² by the pressure adjusters 2261 to 2266. Next inflow valve 2
241-2246 are gradually opened to introduce the respective gases into the mass flow controllers 2211-2216.

After the film-forming preparation is completed by the above procedure, the photoconductive layer is first formed on the cylindrical conductive support 2112.

That is, when the cylindrical conductive support 2112 has reached a desired temperature, each of the outflow valves 2251 to 2251.
Necessary ones of 56 and the auxiliary valve 2260 are gradually opened, and a desired raw material gas is supplied from each of the gas cylinders 2221 to 2226 through the gas introduction pipe 2114 to the reaction vessel 2110.
Introduce inside. Next, each mass flow controller 22
11 to 2216 are adjusted so that each raw material gas has a desired flow rate. At that time, 13 in the reaction vessel 2110
Vacuum gauge 211 so that the desired pressure is 3.3 Pa or less.
While watching 9, the opening of the main valve 2118 is adjusted.
When the internal pressure is stable, the high frequency power supply 2120 is set to a desired power, and the frequency is 1 MHz to 50 MHz, for example.
In particular, high frequency power having a frequency of 13.56 MHz is supplied to the cathode electrode 2111 through the high frequency matching box 2115.
To generate a high frequency glow discharge.

This discharge energy causes the reaction vessel 21 to
Each raw material gas introduced into 10 is decomposed, and a photoconductive layer containing desired silicon atoms as a main component is deposited on the cylindrical conductive support 2112. After the desired film thickness is formed, the supply of high frequency power is stopped and each outflow valve 2251-
2256 is closed to stop the flow of each source gas into the reaction vessel 2110, and the formation of the photoconductive layer is completed.

Known compositions and film thicknesses of the photoconductive layer can be used.

In the case of forming a surface layer on the photoconductive layer, basically, the above operation may be repeated. The surface layer 10
As the film forming gas of No. ₄ , CH ₄ , C ₂ H ₆ , C ₃ H ₈ and C ₄ H
Gases such as ₁₀ and hydrocarbons that can be gasified are mentioned as being effectively used. In addition, these raw material gases for supplying carbon may be diluted with a gas such as H ₂ , He, Ar, or Ne, if necessary.

FIG. 3 is a diagram schematically showing an example of an apparatus for depositing an a-Si photosensitive member by a VHF plasma CVD method using a VHF power source. This apparatus is configured by replacing the deposition apparatus 2100 shown in FIG. 2 with the deposition apparatus 3100 shown in FIG.

Formation of a deposited film by this apparatus by the VHF plasma CVD method can be performed as follows.

First, the conductive support 3112 is installed in the reaction container 3111, the conductive support 3112 is rotated by the driving device 3120, and the inside of the reaction container 3111 is exhausted by an exhaust device (not shown) (for example, a diffusion pump). 3121
The reaction vessel 3111 is evacuated to a pressure of 1.33
It is adjusted to × 10 ^-5 Pa or less. Then, the temperature of the conductive support 3112 is set to 5 by the heater 3113 for heating the support.
It is heated and maintained at a predetermined temperature of 0 to 500 ° C.

The source gas for forming the deposited film is supplied to the reaction vessel 311.
In order to make it flow into 1, the gas cylinder valves 2231-2
236, make sure that the leak valve (not shown) of the reaction vessel is closed, and inflow valves 2241 to 224
6, outflow valves 2251 to 2256, auxiliary valve 226
After confirming that 0 is opened, the main valve (not shown) is first opened to evacuate the reaction vessel 3111 and the gas pipe.

Next, the reading of the vacuum gauge (not shown) is about 6.65.
When the pressure reaches × 10 ^-4 Pa, the auxiliary valve 2260 and the outflow valves 2251 to 2256 are closed.

Then, the valves 2231 to 2236 are opened.
And introduce each gas from the gas cylinders 2221 to 2226.
Then, each gas pressure is adjusted to 2 by the pressure regulators 2261 to 2266.
× 10 ^FiveAdjust to Pa. Next, the inflow valves 2241 to
2246 is gradually opened and each gas is mass flow controlled.
The rollers 2211 to 2216.

After the preparation for film formation is completed as described above, a deposited film is formed on the conductive support 3112 as follows.

When the conductive support 3112 reaches a predetermined temperature, the necessary ones of the outflow valves 2251 to 2256 and the auxiliary valve 2260 are gradually opened, and a predetermined gas is supplied from the gas cylinders 2211 to 2226 to the gas introduction pipe (not connected). Discharge space 3130 in the reaction vessel 3111 via
To introduce. Next, mass flow controller 2211
2216 is adjusted so that each raw material gas has a predetermined flow rate. At that time, the pressure in the discharge space 3130 is 133
The opening of the main valve (not shown) is adjusted while observing the vacuum gauge (not shown) so that the pressure becomes a predetermined pressure of Pa or less.

When the pressure is stable, the frequency is 50 MH.
A VHF power supply (not shown) having a frequency of z to 450 MHz, particularly a frequency of 105 MHz is set to a desired power, and the VHF power is introduced into the discharge space 3130 through the matching box 3116 to cause glow discharge. Thus, the discharge space 3130 surrounded by the conductive support 3112.
In, the introduced source gas is excited by discharge energy and dissociates, and a predetermined deposited film is formed on the conductive support 3112. At this time, simultaneously with the introduction of VHF power, the output of the heater 3113 for heating the support is adjusted to change the temperature of the conductive support at a predetermined value. At this time, in order to make the layer formation uniform, the support rotating motor 3120 is rotated at a desired rotation speed.

After the desired film thickness is formed, the supply of VHF electric power is stopped, the outflow valve is closed to stop the gas from flowing into the reaction vessel, and the formation of the deposited film is completed.

By repeating the same operation a plurality of times, a light receiving member having a desired multilayer structure is formed.

Needless to say, all the outflow valves other than the necessary gas are closed when forming each layer, and each gas is supplied to the reaction vessel 3111.
Inside, outflow valves 2251 to 2256 to reaction vessel 311
In order to avoid remaining in the pipe up to 1, the outlet valves 2251 to 2256 are closed, the auxiliary valve 2260 is opened, and the main valve (not shown) is fully opened to temporarily exhaust the system to a high vacuum. Do as needed.

Needless to say, the above-mentioned gas species and valve operation may be changed according to the conditions for forming each layer.

(B) Charging Step The charging step in the image forming method of the present invention is preferably a contact charging step in which the charging member contacts the image carrier to carry out charging. By contacting and charging, uniform charging is performed even with a small amount of discharge, and it is possible to reduce the occurrence of flow images due to discharge, which is preferable.

Further, at the contact portion between the charging member and the image carrier,
By interposing the above tin oxide fine particles, an injection charging method in which charges are directly injected into the image carrier can be performed, and uniform charging is performed, so that there is no influence of image deterioration due to discharge, which is more preferable. .

Further, from the viewpoint of downsizing and cost reduction, a cleanerless image forming method is further provided, in which a cleaner device is not provided and transfer residual toner remaining on the image carrier after transfer is collected by the toner carrier. preferable.

As a charging method, there is a method of using a contact charging member such as a charging roller member, a charging blade member and a charging brush member.

As the material of the charging roller member and the charging blade member as the contact charging means, conductive rubber is preferable, and the surface of the conductive rubber is releasable in order to prevent contamination of toner, paper powder, etc., for example. You may provide the surface layer which has. As a material for forming the surface layer, a nylon resin,
PVdF (polyvinylidene fluoride), PVdC (polyvinylidene chloride), fluoroacrylic resin, etc. are applicable. Further, in order to adjust the resistance of the surface layer, a conductive pigment such as carbon black, titanium oxide or tin oxide may be appropriately contained.

Specifically, for example, the charging roller member is formed by forming a medium resistance layer such as rubber or foam as a flexible member on the cored bar. The release coating may be provided on the surface. The medium resistance layer is formulated with a resin (for example, urethane), conductive particles (for example, carbon black), a sulfiding agent, a foaming agent, etc., and is formed in a roller shape on the core metal. Thereafter, if necessary, the surface can be cut and the surface can be polished to adjust the shape, and a charging roller member can be prepared.

As the material of the elastic body of the charging roller member,
The material is not limited to rubber or foam, and any elastic material may be used. As the material of the elastic material, ethylene-propylene-diene polyethylene (EPDM), urethane, butadiene acrylonitrile rubber (NBR), silicone rubber, isoprene rubber, etc. In addition, a rubber material in which a conductive material such as carbon black or a metal oxide is dispersed for resistance adjustment, or a material obtained by foaming these materials can be used. Also,
It is also possible to adjust the resistance by using an ion conductive material without dispersing the conductive material or in combination with the conductive material.

The Asker C hardness of the charging roller member is preferably 25 to 50 degrees. If the hardness is too low, the shape is not stable and the contactability with the image bearing member deteriorates.Furthermore, when the tin oxide fine particles are interposed in the contact portion between the charging roller member and the image bearing member, the surface layer of the charging roller member is It is easily scraped or damaged and stable chargeability cannot be obtained. Further, if the hardness is too high, not only the charging contact portion cannot be secured between the image carrier and the microscopic contact property to the surface of the image carrier is deteriorated.

The Asker hardness can be adjusted by adjusting the vulcanization time of rubber, the vulcanization temperature, the thickness of the elastic body, and the size and density of foam cells in the case of foam.

The Asker C hardness of the charging roller can be measured using an Asker C hardness meter. As an outline of the measurement, a roller member is installed at a predetermined position using V blocks to support both ends, an Asker C hardness tester is pressed at a predetermined measurement position of the roller member with a predetermined load, and after a predetermined time from that point. Measure the value of. The point to be noted in the measurement is that the hardness changes depending on the load, the time from pressing to reading the value, the pressing speed, etc. Therefore, in the present invention, the load is 1 kgf (the weight of the hardness meter itself and the external force). Adjust the weight to be added to 1kg) and the pressing speed is 50mm / s
ec.

The measurement points are a total of three points at both ends (arbitrary place within 30 mm from the end) and the central part, and the simple (arithmetic) average of these is used to determine the Asker C of the roller member.
Hardness. It is important that the charging roller member has elasticity to obtain a sufficient contact state with the image carrier and at the same time functions as an electrode having a resistance low enough to charge the moving image carrier. On the other hand, it is necessary to prevent voltage leakage when a defective portion such as a pinhole exists on the image carrier. In order to obtain sufficient chargeability and leakage resistance, a volume resistivity value of 10 ³ to 10 ⁸ Ωcm is preferable, and a resistance value of 10 ⁴ to 10 ⁷ Ωcm is more preferable.

The volume specific resistance value of the charging roller member is measured as follows. Resistance value measured by applying 100 V between the core metal and the aluminum drum in a state where the charging roller member is pressure-bonded to a cylindrical aluminum drum having a diameter of 30 mm so that a total pressure of 1 kg is applied to the core metal of the charging roller member. , Calculated from the nip width during measurement and the thickness of the elastic body.

It is preferable that the surface of the charging roller member has minute cells or irregularities so that tin oxide fine particles intervene. That is, at least the surface of the charging roller member has a dent having an average cell diameter of 5 to 300 μm in terms of sphere, and the porosity of the roller member surface having the dent as a void is 15 to 90%. Is preferred.

Average cell diameter is 5 μm or less, porosity is 90%
If it exceeds, the ability of holding the tin oxide fine particles on the roller member surface decreases, and the amount of the tin oxide fine particles intervening in the contact portion decreases, so that the primary charging property tends to deteriorate. Further, the frictional force with the photoconductor becomes large, and the abrasion of the image carrier increases, which is not preferable. When the average cell diameter exceeds 300 μm and the porosity is 15% or less, the contact uniformity between the charging roller member and the photosensitive member decreases, the charging uniformity of the primary charging property and the charging potential decrease, and halftone images, etc. This is not preferable because it causes image defects such as uneven charging.

The depression can be appropriately formed by forming irregularities on the surface of the mold for molding the charging roller, molding the charging roller, and adjusting the type of foam material, foaming time, and the like. . The cell diameter can be measured by observing the surface of the charging roller with an electron microscope (FE-SEM), and the porosity can be measured by measuring the number of depressions per unit area.

The charging roller member is disposed so as to be pressed against the image carrier with a predetermined pressing force against the elasticity to form a charging contact part which is a contact part between the charging roller member and the image carrier. .
The width of the charging contact portion is not particularly limited, but is preferably 1 mm or more, more preferably 2 mm or more in order to obtain a stable and dense adhesion between the charging roller member and the image carrier.

The charging brush member as the contact charging member is
A commonly used fiber having a resistance adjusted by dispersing a conductive material is used. As the fiber, a generally known fiber can be used, and examples thereof include nylon, acrylic, rayon, polycarbonate, polyester and the like. As the conductive material, a generally known conductive material can be used, and examples thereof include a conductive metal such as nickel, iron, aluminum, gold and silver, or iron oxide, zinc oxide,
Examples thereof include conductive metal oxides such as tin oxide, antimony oxide, and titanium oxide, and conductive powder such as carbon black. If necessary, these conductive materials may be surface-treated for the purpose of making them hydrophobic and adjusting their resistance. At the time of use, it is selected and used in consideration of dispersibility with fibers and productivity.

Specifically as the material of the charging brush member,
Conductive rayon fibers REC-B, R manufactured by Unitika Ltd.
EC-C, REC-M1, REC-M10, SA-7 made by Toray Co., Ltd., Thunderon made by Japan Silkworm Co., Ltd., Bertron made by Kanebo, Cracabo made by Kuraray, carbon on rayon. Dispersed, Mitsubishi Rayon Co., Ltd.'s global etc., but in terms of environmental stability R
EC-B, REC-C, REC-M1, REC-M10
Is particularly preferable.

When a conductive charging brush member is used as the contact charging member, there are a fixed type and a rotatable roll type. As the roll-shaped charging brush member, for example, a tape in which conductive fibers are piled can be spirally wound around a metal cored bar to form a roll brush. The conductive fiber has a fiber thickness of 1 to 20 denier (fiber diameter of about 10 to 500 μm) and a brush fiber length of 1
~ 15mm, brush density 10,000 ~ 3 per square inch
0,000 (1.5 x 10 ^{7 to} 4.5 per square meter
× 10 ⁸ pieces) are preferably used.

From the viewpoint of the primary charging uniformity, it is preferable to use a material having a higher brush density for the charging brush member, and it is also preferable to make one fiber from several to several hundred fine fibers. . For example, it is possible to bundle 50 fine fibers of 300 denier, such as 300 denier / 50 filaments, and to implant them as one fiber.

However, in the present invention, the charging point of the direct injection charging mainly depends on the interposition density of the tin oxide fine particles in the charging contact portion between the charging member and the image carrier and in the vicinity thereof. The range of selection of the brush member is widened, and the brush density may be smaller than that when the charging brush member is used alone.

Next, the amount of tin oxide fine particles present in the contact portion between the image carrier and the contact charging member will be described below.

If the intervening amount of the tin oxide fine particles in the contact portion between the image bearing member and the contact charging member is too small, the tin oxide fine particles cannot sufficiently provide the lubricating effect, so that the image bearing member and the contact charging member are not affected. Due to the large friction, it is difficult to rotationally drive the contact charging member on the image carrier with a speed difference. That is, the driving torque becomes excessively large, and the surface of the contact charging member or the image bearing member is scraped if the driving torque is excessively rotated. Further, the effect of increasing contact opportunities due to the tin oxide fine particles may not be obtained, and sufficient charging performance may not be obtained. On the other hand, if the intervening amount is too large, the amount of tin oxide fine particles coming off from the contact charging member remarkably increases, which adversely affects the image formation.

The intervening amount of tin oxide fine particles was 10 ² particles / mm ²
It is preferably 5 × 10 ⁵ pieces / mm ² . If it is less than 10 ² pieces / mm ² , sufficient lubrication effect and effect of increasing contact opportunity cannot be obtained, and charging performance is deteriorated. Further, when the transfer residual toner is large, charging performance is deteriorated.

The charging by the direct injection charging system is fundamentally different from the discharge charging system, and the charging is performed by surely contacting the charging member with the image bearing member. Even if it is applied excessively on top, there are always parts that cannot be contacted. However, by applying tin oxide fine particles that positively utilize human visual characteristics,
Practically solving this problem.

However, when the direct injection charging method is applied as the uniform charging of the image carrier in the cleaning image formation at the same time of development, the charging characteristics are deteriorated due to the adhering or mixing of the transfer residual toner to the charging member. To prevent the transfer residual toner from adhering to and mixing with the charging member, or overcome the adverse effect on the charging characteristics due to the adhesion or mixing of the transfer residual toner to the charging member, and to perform good direct injection charging, an image carrier The amount of tin oxide fine particles present in the contact portion between the contact charging member and the contact charging member is 10 ² particles / mm ² or more, and more preferably 10 ³ particles / mm ³ or more.

Further, the upper limit of the coating amount of the tin oxide fine particles is until the tin oxide fine particles are uniformly coated on the image bearing member, and further coating does not improve the effect, and conversely. However, there is a problem that the exposure light source is blocked or scattered.

The upper limit of the coating density cannot be generally determined because it depends on the particle size of the tin oxide fine particles, but the upper limit is the amount by which the tin oxide fine particles are uniformly coated on the image carrier in one layer. .

The amount of tin oxide fine particles is 5 × 10 ⁵ particles / m 2.
When it exceeds m ² , the amount of tin oxide particles falling onto the image carrier remarkably increases, and the exposure amount to the image carrier is insufficient regardless of the light transmittance of the tin oxide particles themselves. 5 × 10 ⁵ pieces /
If it is less than or equal to mm ² , the amount of tin oxide particles that fall off can be suppressed to a low level, and the inhibition of exposure can be improved. Image formation was carried out with the intervening amount of tin oxide fine particles being 10 ^{2 to} 5 × 10 ⁵ particles / mm ² , and the amount of tin oxide fine particles that had fallen off on the image bearing member was measured to be 10 ³ to 10 ⁵ particles / mm ^2. It was mm ² , and there was no adverse effect on the image formation. Therefore, the preferable upper limit of the amount of tin oxide particles is 5 × 10 ⁵ particles / mm ² .

A method for measuring the amount of tin oxide fine particles present in the charging contact portion and the amount of tin oxide fine particles present on the image bearing member in the electrostatic latent image forming step will be described. It is desirable to directly measure the interposition amount of the tin oxide fine particles at the contact surface portion of the contact charging member and the image bearing member, but a speed difference is provided between the surface of the contact charging member forming the contact portion and the surface of the image bearing member. In this case, since most of the tin oxide fine particles present on the image bearing member before contacting the contact charging member are stripped off by the contacting charging member while moving in the opposite direction, the present invention immediately before reaching the contact surface portion. The amount of particles on the surface of the contact charging member is defined as the amount of inclusion.

Specifically, the rotation of the image bearing member and the charging roller member is stopped without applying the charging bias, and the surfaces of the image bearing member and the charging roller member are covered with a video microscope (OVM1000N made by OLYMPUS) and a digital still recorder. Photograph with (DELTIS SR-3100). The charging roller member is brought into contact with the slide glass under the same conditions as when the charging roller member is brought into contact with the image carrier, and the contact surface is photographed from the back surface of the slide glass with a video microscope at 10 or more places with a 1000 × objective lens. To do. In order to separate the individual tin oxide fine particles into regions from the obtained digital image, binarization processing is performed with a certain threshold value, and the number of regions in which the tin oxide fine particles are present is measured using desired image processing software. Further, the amount of existence on the image bearing member is also measured by photographing the image bearing member with the same video microscope and performing the same processing.

(C) Electrostatic latent image forming step In the image forming method of the present invention, it is preferable to use an electrostatic latent image forming step of writing image information as an electrostatic latent image on the charged surface of the image carrier by imagewise exposure. . That is, it is preferable that the electrostatic latent image forming means for forming an electrostatic latent image on the charged surface of the image carrier is an image exposing means. The image exposure means for forming an electrostatic latent image is not limited to a laser scanning exposure means for forming a digital electrostatic latent image, but a normal analog image exposure or other light emission such as an LED. An element may be used, or a combination of a light emitting element such as a fluorescent lamp and a liquid crystal shutter may be used as long as it can form an electrostatic latent image corresponding to image information.

(D) Developing Step In the developing step of the image forming method of the present invention, the electrostatic latent image on the image carrier is developed with the toner of the present invention. In particular, it is preferable to develop using a magnetic toner. The toner carrier for the magnetic toner used in the developing step will be described.

The toner carrier used in the present invention is preferably a conductive cylinder (developing roller) formed of a metal or alloy such as aluminum or stainless steel. The conductive cylinder may be formed of a resin composition having sufficient mechanical strength and conductivity, or a conductive rubber roller may be used. Further, the shape is not limited to the cylindrical shape as described above, and may be in the form of an endless belt that is rotationally driven.

In the present invention, 5 to 5 are formed on the toner carrier.
It is preferable to form a toner layer of 50 g / m ² . If the amount of toner on the toner carrier is less than 5 g / m ² ,
It is difficult to obtain a sufficient image density, and unevenness of the toner layer easily occurs due to excessive charging of the toner. When the amount of toner on the toner carrier is more than 50 g / m ² , toner scattering easily occurs.

The surface roughness of the toner carrier used in the present invention is from 0.2 to JIS center line average roughness (Ra).
It is preferably in the range of 3.5 μm.

If Ra is less than 0.2 μm, the amount of charge on the toner carrier tends to be high, resulting in insufficient developability. R
When a exceeds 3.5 μm, unevenness is likely to occur in the toner coat layer on the toner carrier, resulting in uneven density on the image.
More preferably, it is in the range of 0.5 to 3.0 μm.

In the present invention, the surface roughness Ra of the toner carrier is based on JIS surface roughness "JISB 0601" using a surface roughness measuring instrument (Surfcoder SE-30H, Kosaka Laboratory Ltd.). It corresponds to the center line average roughness measured by.

Further, in the present invention, the toner on the toner carrier is regulated by the ferromagnetic metal blade which is disposed facing the toner carrier at a minute interval, so that the toner powder characteristics and charging characteristics are controlled. Is particularly preferable from the viewpoints of maintaining a constant value for a long period of time, being less susceptible to the influence of the temperature and humidity environment, and obtaining a uniform charge in which toner scattering does not easily occur.

Further, in the image forming method of the present invention,
By making the moving speed of the toner carrier that carries the toner in the developing step and conveys it to the developing section to a speed difference with respect to the moving speed of the image carrier, toner particles and tin oxide are transferred from the toner carrier side to the image carrier side. It is preferable because the fine particles can be sufficiently supplied and a good image can be obtained.

The surface of the toner carrying member carrying the toner may move in the same direction as the moving direction of the surface of the image carrying member, or may move in the opposite direction. When the moving directions are the same, the moving speed of the image carrier is 10 as a ratio.
It is preferably 0% or more. If it is less than 100%, the image quality tends to be poor. The higher the moving speed ratio, the greater the amount of toner supplied to the development site,
The toner is frequently attached to and detached from the electrostatic latent image, and unnecessary portions are scraped off and applied to necessary portions, so that an image faithful to the electrostatic latent image can be obtained.

The speed ratio is a value calculated by the following equation (4).

[0243]

## EQU00005 ## Speed ratio (%) = (toner carrier speed / image carrier speed) × 100 (4) Specifically, the moving speed of the toner carrier surface is 1 with respect to the moving speed of the image carrier surface. The speed is preferably 0.05 to 3.0 times.

The developing method in the image forming method of the present invention is preferably a non-contact type developing method in which the image bearing member and the toner bearing member are in non-contact with each other. In the contact developing method, the tin oxide fine particles in the developing section easily inject charges into the image bearing member, which disturbs the electrostatic latent image and easily causes image defects.
Fogging is likely to occur in the developing section, which is not preferable.

In the case of the non-contact developing method, it is preferable that the toner layer on the toner carrier is formed thinner than the distance between the toner carrier and the image carrier. In the developing process, the toner layer is not in contact with the image carrier, and a non-contact developing method is used in which the electrostatic latent image of the image carrier is visualized as a toner image. Even when added to the toner, the developing fog does not occur due to the developing bias injected into the image bearing member. Therefore, a good image can be obtained.

The toner carrier is 1 with respect to the image carrier.
It is preferable that they are installed facing each other with a separation distance of 00 to 1000 μm, and it is further preferable that they are installed facing each other with a separation distance of 120 to 500 μm. If the distance between the toner carrier and the image carrier is smaller than 100 μm, the change in the developing characteristics of the toner with respect to the deviation of the distance becomes large, which makes it difficult to mass-produce image forming apparatuses that satisfy stable image quality. Become. When the distance between the toner carrier and the image carrier is larger than 1000 μm, the collectability of the transfer residual toner to the developing device is deteriorated, and fogging due to defective collection is likely to occur. Further, since the ability of the toner to follow the latent image on the image carrier is deteriorated, the resolution is lowered and the image density is lowered, which leads to deterioration in image quality.

In the developing step, the development is preferably carried out by applying an alternating electric field to the toner carrier, and the applied developing bias may superimpose an alternating voltage (AC voltage) on the DC voltage.

As the waveform of the alternating voltage, a sine wave, a rectangular wave, a triangular wave or the like can be appropriately used. Further, it may be a pulse wave formed by periodically turning on / off the DC power supply. Thus, as the waveform of the alternating voltage, a bias whose voltage value changes periodically can be used.

At least the peak-to-peak electric field strength is 3 × 10 ⁶ to 10 × 10 ⁶ V / m, and the frequency 100
It is preferable to apply an alternating electric field of ˜5000 Hz as a developing bias between the toner carrying member carrying the toner and the image carrying member. If the electric field strength of the developing bias applied between the toner carrying member and the image carrying member is smaller than 3 × 10 ⁶ V / m, the collectability of the transfer residual toner to the developing device is deteriorated, and the fog due to the collection failure occurs. Is likely to occur. Further, since the developing power is small, an image having a low image density is likely to be obtained. On the other hand, when the electric field strength of the developing bias is larger than 10 × 10 ⁶ V / m, the developing power is too large and the resolution is deteriorated due to the collapse of fine lines, and the image quality is easily deteriorated due to the increase of fog. Image defects are more likely to occur due to leaks to the carrier. Further, the frequency of the AC component of the developing bias applied between the toner carrier and the image carrier is 10
When the frequency is less than 0 Hz, the toner is less frequently attached to and detached from the electrostatic latent image, the collectability of the transfer residual toner to the developing device is easily deteriorated, and the image quality is also easily deteriorated. When the frequency of the AC component of the developing bias is higher than 5000 Hz, the amount of toner that can follow the change in the electric field is reduced, so that the collectability of the transfer residual toner is lowered and the developability is lowered.

Even if there is a high potential difference between the toner carrier and the image carrier due to application of an alternating electric field as a developing bias, charge is not injected into the image carrier by the developing unit. The tin oxide fine particles added therein are likely to be uniformly transferred to the image bearing member side, and the tin oxide fine particles are uniformly applied to the image bearing member, and uniform contact is made at the charging portion, so that good chargeability can be obtained. .

In the case of a non-magnetic toner, the toner carrier as described above can be used, but it may be mixed with a developing carrier and developed by a two-component developing method.

(D) Transfer Step The transfer step in the image forming method of the present invention is preferably a contact transfer step.

In the present invention, the recording medium to which the toner image is transferred from the image carrier may be an intermediate transfer member such as a transfer drum. When the recording medium is an intermediate transfer member, a toner image can be obtained by transferring the intermediate transfer member to a transfer material such as paper again.

In the contact transfer step, the toner image is electrostatically transferred onto the transfer material while the transfer means is in contact with the image carrier via the transfer material. The contact pressure of the transfer means is linear pressure 2. It is preferably 9.9 N / m (3 g / cm) or more, more preferably 19.6 N / m (20 g / cm) or more. The linear pressure as a contact pressure is 2.9 N / m (3 g
/ Cm) is not preferable because the transfer material may be misaligned or transfer failure may occur.

As the transfer means in the contact transfer step, an apparatus having a transfer roller or a transfer belt is used, and a transfer bias is applied by a transfer bias power source. The transfer roller includes at least a cored bar and a conductive elastic layer. The conductive elastic layer is made of urethane or EPDM in which a conductive material such as carbon is dispersed and has a volume resistance of 10 ⁶ to 10 ^6.
It is composed of an elastic body of about ¹⁰ Ωcm.

<3> Image Forming Apparatus of the Present Invention The image forming apparatus of the present invention uses the image forming method of the present invention, and includes the above image carrier, charging means using the above charging step, and the above electrostatic. The toner is provided using at least an electrostatic latent image forming means using the latent image forming step, a developing means using the developing step, and a transferring means using the transfer step.

[0257]

EXAMPLES The photoconductor and toner used in the image forming method of the present invention, the tin oxide fine particles used in the toner, and the charging member will be described below. The present invention is not limited to these production examples.

<Production of a-Si Photoreceptor> After stacking a charge injection blocking layer and a photoconductive layer on a cylindrical conductive support under the following conditions using the plasma CVD apparatus shown in FIG.
A surface layer of 0.5 μm was deposited to manufacture a-Si type photoconductors 1 to 6. The charge injection blocking layer and the photoconductive layer of the a-Si photoconductors 1 to 6 were formed under the same conditions. As a sample for measuring the silicon atom content and the hydrogen content of the surface layer, a surface layer sample was prepared on each of the glass substrate and the silicon wafer under the same conditions as the a-Si type photoconductors 1 to 6.

(Production of a-Si Photoreceptor 1) Charge Injection Blocking Layer-SiH ₄ 100 ml / min (normal) -H ₂ 300 ml / min (normal) -PH ₃ 800 ppm (relative to SiH ₄ ) -NO 5 ml / Min (normal) -Power 150 W (13.56 MHz) -Internal pressure 80 Pa-Support temperature 280 ° C.-Thickness 3 μm Photoconductive layer-SiH ₄ 350 ml / min (normal) -H ₂ 600 ml / min (normal) -B ₂ H ₆ 0.5 ppm (relative to SiH ₄ ), power 400 W (13.56 MHz), internal pressure 73 Pa, support temperature 280 ° C., film thickness 20 μm surface layer, CH ₄ 500 mL / min (normal), power 1000 W (13. 56MHz) ・ Internal pressure 66.7Pa ・ Support temperature 200 ℃

(Production of a-Si Photoreceptor 2) Surface Layer CH ₄ 500 mL / min (normal) Power 800 W (13.56 MHz) Internal Pressure 13.3 Pa Support Temperature 300 ° C.

(Production of a-Si Photoreceptor 3) Surface Layer-CH ₄ 500 mL / min (normal) -Power 1500 W (13.56 MHz) -Internal Pressure 13.3 Pa-Support Temperature 300 ° C.

(Production of a-Si Photoreceptor 4) Surface Layer CH ₄ 100 mL / min (normal) H ₂ 200 mL / min (normal) Power 500 W (13.56 MHz) Internal Pressure 6.7 Pa Support Temperature 150 ℃

(Production of a-Si-based Photoreceptor 5) Surface Layer CH ₄ 100 mL / min (normal) H ₂ 200 mL / min (normal) Power 500 W (13.56 MHz) Internal Pressure 4.0 Pa Support Temperature room temperature

(Production of a-Si Photoreceptor 6) Surface Layer-SiH ₄ 0.4 mL / min (normal) -CH ₄ 100 mL / min (normal) -H ₂ 200 mL / min (normal) -Power 500 W (13) .56 MHz) -Internal pressure 40.0 Pa-Support temperature 250 ° C Table 1 shows the physical properties of the photoconductors 1-6.

[0265]

[Table 1]

<Manufacture of Charging Member> (Manufacture of Charging Member 1) SUS having a diameter of 6 mm and 320 mm
A roller is used as a core metal, a urethane resin on the core metal, carbon black as a conductive material, a sulfidizing agent, a foaming agent having a medium resistance, which is formulated with a foaming agent, is formed into a roller shape, which is further cut and ground to form and Surface properties were adjusted, and a charging roller member 1 having a diameter of 12 mm and 320 mm was prepared as a flexible member.

(Production of Charging Member 2) A charging roller member 2 was produced in the same manner as the charging member 1 except that the amount of carbon black added was 10 times that of the charging member 1.

(Production of Charging Member 3) A charging roller member 3 was produced in the same manner as the charging member 1 except that carbon black was not added.

(Production of charging member 4) Diameter 6,320 mm
The SUS roller was used as a core metal, and a tape having a conductive nylon fiber piled on the core metal was spirally wound around a metal core metal to prepare a roll-shaped charging brush member 4.
As a tape using conductive nylon fiber as a pile fabric,
The thickness of the fiber whose resistance is adjusted by dispersing carbon black in nylon fiber is 6 denier (300 denier / 50
A filament was used, and the length of the fiber of the brush was 3 mm, and the brush density was 100,000 fibers per square inch.

(Production of charging member 5) Silicone rubber 100 parts by mass Paraffin oil 10 parts by mass Zinc oxide 6 parts by mass Higher fatty acid 1 part by mass Conductive carbon black 5 parts by mass The above materials were adjusted to 50 ° C. The raw material compound is adjusted by kneading for 10 minutes with an internal mixer, and 2 parts by mass of sulfur as a vulcanizing agent and 100 parts by mass of silicone rubber as a raw material and MBT (2
-Mercaptobenzothiazole) and TMT
1.5 parts by mass of D (tetramethylthiuram disulfide) and 1.5 parts by mass of ZnMDC (zinc dimethyldithiocarbamate) were added, and the mixture was kneaded for 10 minutes with a two-roll machine cooled to 20 ° C. to prepare a rubber compound. .

On the other hand, a core metal made of stainless steel having a diameter of 9 mm was prepared, and the above rubber compound was fed and molded on the core metal by an extrusion molding machine so as to form a roller having an outer diameter of 16 mm. It was heated and vulcanized for minutes to prepare an elastic roller having a volume resistivity of 4 × 10 ³ Ωcm.

As the surface layer, N-methoxymethylated nylon (trade name: resin, Teikoku Chemical Industry Co., Ltd.)
5 parts by mass of zinc oxide is added to 100 parts by mass of
A resin solution dispersed in a ball mill for 4 hours was prepared, a surface layer was applied to the elastic roller by dipping using this resin solution, and dried by heating at 120 ° C. for about 1 hour to obtain a surface layer having a thickness of 20 μm. Charging roller member 5 having
Got

The physical properties of the charging members 1 to 5 are shown in Table 2 below.

[0274]

[Table 2] <Production of Tin Oxide Fine Particles> (Production of Tin Oxide Fine Particles 1) Tin chloride (SnCl ₄ .5H ₂ ) so that the molar ratio (W / Sn) of tungsten element (W) and tin element (Sn) is 4 mol%. O) and an aqueous solution of tungstic acid (H ₂ WO ₄ ) are mixed, and the mixture is heated and mixed at 90 ° C. while maintaining the pH at 6.5 to 7.5, and then hydrochloric acid is added to form a coprecipitate. Filtered / dried.

[0275] The dried product was put into an electric furnace (600
C.) and crush / classify to obtain tin oxide fine particles 1.

(Production of Tin Oxide Fine Particles 2) In the production of tin oxide fine particles 1, tin oxide fine particles 2 were obtained by changing W / Sn = 8 mol% and further changing firing conditions and crushing / classification conditions. . (Production of Tin Oxide Fine Particles 3) In the production of the tin oxide fine particles 1, the firing was changed to W / Sn = 1 mol%. The fired product was crushed / classified to obtain tin oxide fine particles 3.

(Production of Tin Oxide Fine Particles 4) In the production of the tin oxide fine particles 1, the tin oxide fine particles 4 were changed by changing W / Sn = 0.06 mol% and further changing the firing conditions and the crushing / classifying conditions. Obtained. (Production of Tin Oxide Fine Particles 5) In production of the tin oxide fine particles 1, firing was performed with W / Sn changed to 0.2 mol%. Tin oxide fine particles 5 were obtained by crushing / classifying the fired product.

(Production of Tin Oxide Fine Particles 6) In the production of the tin oxide fine particles 1, the W / Sn was changed to 27 mol%,
Further, the firing conditions and the crushing / classifying conditions were changed to obtain tin oxide fine particles 6. (Production of Tin Oxide Fine Particles 7) In the production of the tin oxide fine particles 1, the firing was changed to W / Sn = 32 mol%.
The fired product was crushed / classified to obtain tin oxide fine particles 7. However, tin and tungsten undergo phase separation, resulting in soft particles lacking tungsten. When it was added to the toner particles and evaluated, the development characteristics were adversely affected and a fog image was obtained.

(Production of Tin Oxide Fine Particles 8) In the production of tin oxide fine particles 1, the conditions of crushing / classification were changed to adjust the volume average particle diameter. This is designated as tin oxide fine particles 8. (Production of Tin Oxide Fine Particles 9) In the production of the tin oxide fine particles 1, the crushing / classifying conditions were changed to adjust the volume average particle diameter.
This is designated as tin oxide fine particles 9.

(Production of Tin Oxide Fine Particles 10) In the production of tin oxide fine particles 1, the conditions of crushing / classification were changed to adjust the volume average particle diameter. This is designated as tin oxide fine particles 10. (Production of Tin Oxide Fine Particles 11) In the production of the tin oxide fine particles 1, the crushing / classifying conditions were changed to adjust the volume average particle diameter. This is designated as tin oxide fine particles 11.

(Production of Tin Oxide Fine Particles 12) Sb and Sn
The tin chloride and antimony chloride having a molar ratio (Sb / Sn) of 2 mol% were hydrolyzed in hot water, and the coprecipitate was baked in an electric furnace to obtain antimony-containing tin oxide fine particles 12. The tin oxide fine particles 12 had a black blue color. When these particles were added to the toner particles and evaluated, a bluish black fogging image was generated on a white background.

(Production of Tin Oxide Fine Particles 13) Tin oxide fine particles (SnO ₂ ) 1 not intentionally containing a different element
Got 3. (Production of Tin Oxide Fine Particles 14) The tin oxide fine particles 13 were fired in a hydrogen gas atmosphere to obtain black tin oxide fine particles 14 in which a part of SnO ₂ was reduced.

(Production of Tin Oxide Fine Particles 15) An aqueous solution of tin chloride (SnCl ₄ .5H ₂ O) and phosphorus trichloride (PCl) so that the molar ratio of P and Sn (P / Sn) is 9 mol%.
The aqueous solution of ₃ ) was mixed, the mixture was heated and mixed at 80 ° C. while maintaining the pH at 6.5 to 7.5, hydrochloric acid was added, and the coprecipitate formed was filtered / dried.

The dried product was fired in an electric furnace at 700 ° C. and crushed / classified to obtain tin oxide fine particles 15.

In Table 3, the content of tungsten element, antimony element and phosphorus element with respect to tin element in the tin oxide fine particles 1 to 15 is mol%, the volume average particle diameter is 23 ° C./60%.
And the resistance value under 23 ° C./5% environment.

[0286]

[Table 3] In the tin oxide fine particles 1 to 12, the particles are immersed in an aqueous hydrochloric acid solution, the tin oxide fine particles immersed in the aqueous hydrochloric acid solution are separated from the aqueous hydrochloric acid solution, and the particles are taken out to obtain E particles.
Surface analysis was performed by SCA. It was confirmed that the atomic% of the elemental tungsten, the element antimony, and the elemental phosphorus decreased at almost the same ratio as the time of immersion in the aqueous hydrochloric acid solution increased. From this, it was found that the elements of tungsten, antimony and phosphorus were mainly present on the surface.

Further, the mol% of tin element, tungsten element, antimony element, and phosphorus element was determined by the inductively coupled plasma optical emission spectroscopy analyzer (ICP-AES) to determine the content of elements other than tin element with respect to tin. The contents of the element, the antimony element, and the phosphorus element were analyzed by an inductively coupled plasma optical emission spectroscopy analyzer (ICP-AES), and converted to mol to calculate mol%.

From Table 3, it was found that the tin oxide fine particles containing the tungsten element, the antimony element and the phosphorus element had less variation in resistance due to the environment than the tin oxide fine particles containing no tin oxide fine particles.

<Manufacture of Toner Particles> (Manufacture of Toner Particles 1) 0.1 to 709 g of ion-exchanged water
After adding 451 g of M-Na ₃ PO ₄ aqueous solution and heating to 60 ° C., 67.7 g of 1.0 M-CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . -Styrene 80 parts by mass-n-butyl acrylate 20 parts by mass-Unsaturated polyester resin 2 parts by mass-Saturated polyester resin 3 parts by mass-Negatively charge controlling agent (monoazo dye-based Fe compound) 1.2 parts by mass-Surface treatment Hydrophobized magnetic material 95 parts by mass The above formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Kakoki Co., Ltd.). This monomer composition was heated to 60 ° C., and an ester wax containing behenyl behenate as a main component (maximum value of endothermic peak in DSC 72
C) 6 parts by mass are added, mixed and dissolved, and the polymerization initiator 2,
2'-azobis (2,4-dimethylvaleronitrile)
[T1 / 2 = 140 minutes, at 60 ° C.] 5 g was dissolved.

[0290] The above polymerizable monomer system was put into the above aqueous medium, and the mixture was 10,000 rpm at 60 ° C under N ₂ atmosphere using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.).
Stir for 15 minutes and granulate. Then, the mixture was reacted at 60 ° C. for 6 hours while stirring with a paddle stirring blade. Then increase the liquid temperature to 8
The temperature was raised to 0 ° C. and stirring was continued for another 4 hours. After the reaction is completed, 80 ℃
Then, the suspension is cooled, hydrochloric acid is added to dissolve Ca ₃ (PO ₄ ) ₂ , and the mixture is filtered, washed with water and dried to obtain toner particles 1 having a weight average particle diameter of 7.0 μm. Got

(Production of Toner Particles 2) The toner particles 1 obtained in the production of the toner particles 1 were melt-kneaded at 130 ° C. using a twin-screw extruder. The melt-kneaded product was crushed using a hammer mill to obtain a 1-mm mesh-pass toner crushed product. Further, this coarsely pulverized product was finely pulverized by a collision type pulverizer using a jet stream and then classified by wind force to obtain toner particles 2 having a weight average particle diameter of 7.3 μm.

(Production of Toner Particles 3) Polyester resin (Tg 60 ° C., molecular weight: Mp6900, Mn3050,
Mw54500) 100 parts by mass, monoazo metal complex (negative charge control agent) 3.0 parts by mass, low molecular weight ethylene-propylene copolymer (endothermic main peak temperature: 86 ° C, exothermic main peak temperature: 86.5 ° C) 3. After mixing 5 parts by mass with a Henschel mixer, the mixture was kneaded with a biaxial kneader set to a temperature of 130 ° C. to obtain a kneaded product. The kneaded product was cooled, roughly crushed using a hammer mill, and then crushed by a mechanical crusher (turbo mill). Further, classification was carried out by an airflow classifier to obtain non-magnetic toner particles 3 having a weight average particle diameter of 7.5 μm.

(Production of Toner Particles 4) 10 parts by mass of tin oxide fine particles are added to the toner particles 1 obtained in the production of Toner Particles 1 and melt-kneaded at 130 ° C. using a twin-screw extruder to obtain a melt-kneaded product. Got The melt-kneaded product was crushed using a hammer mill to obtain a 1-mm mesh-pass toner crushed product. Further, this coarsely pulverized product was finely pulverized by a collision type pulverizer using a jet stream and then classified by wind force to obtain toner particles 4 having a weight average particle diameter of 7.5 μm.

Further, since the value of the volume average particle diameter of the toner particles was almost the same as the value of the weight average particle diameter, it is considered that the value of the volume average particle diameter is the same as the value of the weight average particle diameter. I don't care.

<Manufacture of Toner> (Manufacture of Toner 1) To 100 parts by mass of Toner Particle 1, 1.5 parts by mass of tin oxide fine particles 1 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added. Externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) to obtain Toner 1. (Production of Toner 2) To 100 parts by mass of Toner Particle 1, 1.8 parts by mass of tin oxide fine particles 2 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added, and a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) was added. Externally added to obtain Toner 2.

(Production of Toner 3) Toner Particle 1 100
1.2 parts by mass of tin oxide fine particles 3 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added to parts by mass, and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Toner 3 was obtained. (Production of Toner 4) To 100 parts by mass of Toner Particle 1, 0.8 parts by mass of tin oxide fine particles 4 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added, and a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) was added. Externally added to obtain Toner 4.

(Production of Toner 5) Toner Particle 1 100
To 1.0 part by mass of tin oxide fine particles, 5 parts by mass of tin oxide and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Toner 5 was obtained. (Production of Toner 6) To 100 parts by mass of Toner Particle 1, 2.0 parts by mass of tin oxide fine particles 6 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added, and a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) was added. Externally added to obtain Toner 6.

(Production of Toner 7) Toner Particle 1 100
2.4 parts by mass of tin oxide fine particles 7 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added to parts by mass, and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Toner 7 was obtained. (Production of Toner 8) To 100 parts by mass of Toner Particle 1, 0.8 parts by mass of tin oxide fine particles 8 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added, and a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) was used. Externally added to obtain Toner 8.

(Production of Toner 9) Toner Particle 1 100
0.5 parts by mass of tin oxide fine particles 9 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added to parts by mass, and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Toner 9 was obtained. (Production of Toner 10) To 100 parts by mass of Toner Particle 1,
3.5 parts by mass of tin oxide fine particles 10 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) to prepare toner 10. Obtained.

(Production of Toner 11) Toner Particle 1 10
4.5 parts by weight of tin oxide fine particles 11 and 1 part by weight of hydrophobic silica fine powder treated with dimethyl silicone oil were added to 0 parts by weight, and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Then, Toner 11 is obtained. (Production of Toner 12) To 100 parts by mass of Toner Particle 1,
1.5 parts by mass of tin oxide fine particles 12 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added and externally added using a Henschel mixer (Mitsui Miike Kako Co., Ltd.) to prepare toner 12. Obtained

(Production of Toner 13) Toner Particle 1 10
1.5 parts by weight of tin oxide fine particles 13 and 1 part by weight of hydrophobic silica fine powder treated with dimethyl silicone oil were added to 0 parts by weight and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Then, Toner 13 is obtained (Production of Toner 14)
1.5 parts by mass of tin oxide fine particles 14 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) to prepare toner 14. Obtained

(Production of Toner 15) Toner Particle 1 10
2.1 parts by mass of tin oxide fine particles 15 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added to 0 parts by mass, and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Then, the toner 15 is obtained (manufacture of Toner 16), the amount of the tin oxide fine particles 1 added is 4.0 parts by mass in the manufacture of the toner 1, and the external addition time of the Henschel mixer is 1 / time of the time of manufacturing the toner 1. 25
Toner 16 was obtained in the same manner as Toner 1 except that the toner was doubled.

(Production of Toner 17) Toner Particles 4 10
To 0 parts by mass, 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil was added and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) to prepare toner 17
Got (Production of Toner 18) To 100 parts by mass of Toner Particle 1,
Toner 18 was obtained by adding 12 parts by mass of tin oxide fine particles 1 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil and using a Henschel mixer (Mitsui Miike Kako Co., Ltd.). .

(Production of Toner 19) Toner Particle 1 10
0.13 parts by mass of tin oxide fine particles 1 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added to 0 parts by mass and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.). Then, Toner 19 is obtained. (Production of Toner 20) To 100 parts by mass of Toner Particles 2,
2.4 parts by mass of tin oxide fine particles 1 and 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil were added and externally added using a Henschel mixer (Mitsui Miike Kako Co., Ltd.) to prepare toner 20. Obtained.

(Production of Toner 21) Toner Particles 3 10
1.0 part by weight of tin oxide fine particles 1 and 0 parts by weight of hydrophobic silica fine powder 1 treated with dimethyl silicone oil
Parts by weight and externally added using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.) to obtain a toner 21. (Production of Toner 22) To 100 parts by mass of Toner Particle 1,
Toner 22 was obtained by adding 1 part by mass of hydrophobic silica fine powder treated with dimethyl silicone oil and externally adding it using a Henschel mixer (Mitsui Miike Kakoki Co., Ltd.).

Table 4 shows the volume average particle size of the tin oxide fine particles in the toner state, the liberation rate, the amount present per toner, the weight average particle size of the toner, the circularity, and the magnetization intensity.

The volume average particle diameter of the toner is
Since it was almost the same as the value of the weight average particle diameter, it may be considered that the value of the volume average particle diameter is the same as the value of the weight average particle diameter.

[0308]

[Table 4]

[0309]

Examples 1 to 8 and Comparative Examples 1 to 5 An organic photoconductor digital copying machine (GP405, manufactured by Canon Inc.) using a laser beam was prepared as an electrophotographic apparatus. The apparatus is provided with a charging roller as a charging means for a photoconductor, and as a developing means, a one-component developing device adopting a one-component jumping developing method in which the toner on the toner carrier and the photoconductor are not in contact with each other. And a blade cleaning means and a pre-charging exposure means. Further, the charging roller, the blade cleaning means and the photoconductor are a one-piece unit. Process speed is 210mm /
s. The device was modified as follows.

First, the charging roller is changed to the charging member 5 manufactured as described above, and the central wavelength of laser and pre-exposure is 660 nm.
The organic photoconductor was changed to the a-Si-based photoconductor prepared above.

The charging voltage applied to the charging member is -500.
The DC voltage of V is superposed with the sine wave of 1.85 kHz and 2.1 kVpp, and it is applied from the external power source so as to be applied in synchronization with the timing of rotation of the photoconductor, and the transfer voltage is controlled from the photoconductor. When the image is formed, the voltage is controlled so as to be +15 μA during the image formation, and the developing voltage is a voltage in which a rectangular wave of 800 Vpp / 1.8 kHz is superposed on a DC component of −260 V during the image formation. In the non-image formation, the one controlled so that only the direct current voltage of -260 V is applied was used.

Evaluation environment 23 using the above image forming apparatus
An image ratio of 5% was applied to 100,000 sheets of A4 horizontal paper at a temperature of / 5%, and evaluation was performed according to the following evaluation method. Evaluation 1) Evaluation of fog image and image density After passing 1000 sheets, a solid white image is printed on A3 size paper, and the fog in the solid white area is reflected by a reflection densitometer (TOKYO DE
NSHOKU's REFLECTOMETER MODEL TC-6DS) was used to measure the average reflection density of the white background after image formation.
Evaluation was performed according to the following evaluation criteria with w and (Dw-Dr) when the average reflection density of the paper before image formation was Dr. ◎: Fogging is less than 1.5% ○: Fogging is 1.5% or more and less than 3% △: Fogging is 3% or more and less than 5% ×: Fogging is 5% or more

Evaluation 2) Evaluation of primary charging property (charging potential, charging uniformity) due to contaminants that have slipped through cleaning due to endurance At the beginning of endurance and after passing 100,000 sheets, the developing unit at the beginning of endurance is replaced with an A3 size sheet. On paper, a solid black image is printed 20 cm from the front edge of the image, and a solid white image is displayed after that, and the fogging of the solid white portion immediately after the solid black is reflected by a reflection densitometer (TOKYO DENSHOKU
Measured using REFLECTOMETER MODEL TC-6DS manufactured by Co., Ltd., the average value of the reflection density of the white background after printing 300,000 sheets is Dw,
Ds is the initial durability and D is the average reflection density of the paper before printing.
(Ds-Dr) and (Dw-Dr) are defined as r, and the difference between the fog amounts ((Dw-Dr)-(Ds
-Dr)) was evaluated according to the following evaluation criteria to evaluate the primary charging property.

Since the solid black-solid white image is a process of causing the charging member to rapidly rise from the light potential of the photoconductor, the primary charging ability appears as a significant difference, and the charging ability is uniform. If the charging property is lowered, the primary potential is lowered and the background fog is apt to occur. Therefore, the charging property is evaluated by the above evaluation. A: Difference in fog is less than 1.5%. O: Difference in fog is 1.5% or more and less than 3%. B: Difference in fog is 3% or more and less than 5%. X: Difference in fog is 5% or more. The photoreceptors, toners, charging members and evaluation results used in Examples 1 to 8 and Comparative Examples 1 to 5 are shown.

[0315]

[Table 5]

[0316]

Examples 9 to 36, Comparative Examples 6 to 11 Next, examples of an image forming method using a cleanerless system will be described.

An organic photoconductor digital copying machine (GP405, manufactured by Canon Inc.) using a laser beam was prepared and modified as follows to obtain the image forming apparatus shown in FIG.

First, in the charging portion, the tin oxide fine particles contained in the toner used were applied to the charging member manufactured as described above in place of the charging roller so as to be evenly distributed at 10 ⁴ / mm ² on the surface of the charging member. The charging member 306 was attached. In addition,
When the toner contained no tin oxide particles, tin oxide particles 1 were used. In order to rotate the charging member, the rotation motor is modified from the outside so that it can be attached to the core metal part of the charging member, and the rotation of the charging member is controlled to be synchronized with the rotation of the photosensitive member of the machine. Is rotated so as to move in a direction opposite to the moving direction of the surface of the photosensitive member at the portion in contact with the photosensitive member (the photosensitive member rotates in the direction of arrow A and the charging member rotates in the direction of arrow B in FIG. 5), and the peripheral speed ratio is 120. % Controlled.

Further, the central wavelength of the laser and the pre-exposure L is set to 66.
The thickness was changed to 0 nm, and a prepared above was used instead of the organic photoreceptor.
An image forming apparatus of a cleanerless system was prepared in which the Si-based photoreceptor 1 was mounted and the cleaning blade was removed.

The charging voltage applied to the charging member is -500V.
The DC voltage is set to a constant current control in which the voltage is controlled to +13 μA during image formation in which an image is transferred from the photoconductor, and the developing voltage is set to −2 during image formation.
A direct current component of 60 V and a rectangular wave of 800 Vpp / 1.8 kHz are superposed, and it is -260 V at the time of non-image formation.
The one controlled so as to apply only the DC voltage was used.

Durability evaluation was carried out using the above-mentioned image forming apparatus, and evaluation was carried out according to the following evaluation methods. Evaluation 1) Charge potential evaluation of the photoconductor In an environment of 23 ° C / 5%, the durability of 100,000 sheets of A4 landscape paper with an image ratio of 5% was evaluated, and the dark potential of the photoconductor before and after passing the paper was taken as the center in the longitudinal direction of the photoconductor. The measurement was carried out at the developing portion at the position (Model 344 surface potential meter Trek Co., Ltd.), and the evaluation was performed according to the following evaluation criteria. ⊚: Charging potential −350 or more ○: Charging potential −300 or more and less than −350 Δ: Charging potential −250 or more and less than −300 Δx: Charging potential −200 or more and less than −250 ×: Charging potential less than −200

Evaluation 2) Evaluation of transferability Under an environment of 23 ° C./5%, A4 image ratio 5%, A4 horizontal paper 10
Transfer process part during solid black image formation after passing 10,000 sheets
While the paper is passing, stop the photoconductor and charging member, tap the areas between the transfer-charging and development-transfer of the photoconductor with Mylar tape and attach it to the stripping evaluation paper. , And the average reflection density of the transfer residue, Dtr, the reflection density between development and transfer, Ddev, and the reflection density of the tape only, Dtp. Measure efficiency,
The evaluation was performed according to the following evaluation criteria.

Transfer efficiency (%) = ((Ddev-Dtp)-(Dtr-Dt
p)) / (Ddev-Dtp) × 100 ◎: Transfer efficiency is 90% or more ○: Transfer efficiency is 85% or more and less than 90% △ ×: Transfer efficiency is 80% or more and less than 85%

Evaluation 3) Evaluation of fogging image and image density Under a 23 ° C./5% environment, after passing 1000 sheets of A4 image ratio 5%, a solid white image is printed on A3 size paper,
Reflective densitometer (TOKYO DENSHOKU Co., Ltd.)
(Manufactured by REFLECTOMETER MODEL TC-6DS), and the average reflection density value of the white background after image formation is solid white Dw, and the average reflection density value of the paper before image formation is Dr (Dw- D
The evaluation was performed according to the following evaluation criteria with r) as the fog amount. ◎: Fogging is less than 1.5% ○: Fogging is 1.5% or more and less than 3% △: Fogging is 3% or more and less than 5% ×: Fogging is 5% or more

Evaluation 4) Evaluation of Abrasion of Photoreceptor The above 200,000 sheets of paper were passed through an A4 image ratio of 5% at 23 ° C./5%.
Performed in an environment, measure the film thickness of the surface layer before and after passing the paper with a reflection spectroscopic interferometer (MCPD2000 manufactured by Otsuka Electronics Co., Ltd.), and calculate the film thickness from this value and the known refractive index. The evaluation was performed according to the following evaluation criteria. ◎: The wear amount was not detected within the measurement error and was very good. ○: It was worn, but it was slight and no image defect due to abrasion was observed. △: It was slightly worn and the primary potential decreased. The image was slightly fogged. Δ ×: A large amount of wear, a decrease in primary potential was observed, and slight fogging occurred in the image.

Evaluation 5) Evaluation of Toner Scattering Due to Durability The above 10,000 sheets of paper were passed at 32 ° C./80 at an A4 image ratio of 15%.
% Under the environment, the developing device was observed after passing the paper, and the evaluation was performed according to the following evaluation criteria. ◯: Good without being scattered on the developing blade Δ: Slightly scattered on the developing blade.

Table 6 shows Examples 9 to 36 and Comparative Examples 6 to 11.
The photoconductors, toners, charging members, and evaluation results used in the above are shown.

[0328]

[Table 6]

[0329]

According to the present invention, a uniform charging potential can be obtained without lowering the primary charging property even after long-term durability. Further, even when a cleanerless system in which a cleaning and image forming method for simultaneous development is combined is adopted, uniform charging can be obtained, and a clear image can be obtained for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an a-Si based photoreceptor used in an image forming method and an image forming apparatus of the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a deposition apparatus used for manufacturing an a-Si based photoreceptor by an RF plasma CVD method.

FIG. 3 is a schematic configuration diagram showing an example of a deposition apparatus used for manufacturing an a-Si based photosensitive member by a VHF plasma CVD method.

FIG. 4 is a schematic view of an apparatus for measuring the volume resistance value of tin oxide fine particles according to the present invention.

FIG. 5 is a schematic view of one embodiment of an image forming apparatus of the present invention.

[Explanation of symbols]

101: conductive support 102: Charge injection blocking layer 103: Photoconductive layer 104: surface layer 105: charge generation layer 106: charge transport layer 2100, 3100: Deposition device 2110, 3111: Reaction vessel B: cell 21, 22: electrodes 23: Guide ring 24: Ammeter 25: Voltmeter 26: Constant voltage device 27: Measurement sample 28: Insulator 1: photoconductor 306: Charging member 307: Developing device 11a: Development blade 12: toner carrier 13: Toner 14: Magnet 301: Transfer material 302: Transfer roller 313: fixing device P: Pre-exposure L: Image exposure

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/02 102 G03G 15/08 507B 15/08 507 9/08 101 (72) Inventor Tsuyoshi Takiguchi Tokyo 3-30-2 Shimomaruko, Ota-ku Canon Inc. (72) Inventor Masanori Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H005 AA02 AA08 AA15 CB07 EA01 EA02 EA05 EA10 FA06 2H068 DA12 DA23 2H077 AA37 AC11 AC16 AD02 AD06 EA16 GA03 2H200 FA02 GA18 GA23 GA44 GB37 HA02 HA21 HA28 HB07 HB12 HB17 HB45 HB46 HB47 HB48 JA01 JB10 MA02 MB06 MC02 MC13 MC15 NA02

Claims (44)

[Claims] 1. A charging step of applying a voltage to a charging member to charge an image carrier, an electrostatic latent image forming step of forming an electrostatic latent image on the charged image carrier, and a toner carrier. A developing step of transferring the toner carried on the electrostatic latent image held on the surface of the image carrier to form a toner image, and the toner image formed on the image carrier as a transfer material. In the image forming method including at least a transfer step of electrostatically transferring, the image carrier is composed of a conductive support and an amorphous material having a silicon atom as a main component and provided on the conductive support. An amorphous silicon-based photoconductor having a photoconductive layer, wherein the toner contains at least a binder resin, a colorant, and tin oxide fine particles, and the tin oxide fine particles are 0.1 to 30 mol with respect to tin element. % Tungsten element / Or the image forming method characterized by comprising the phosphorus element. 2. The image forming method according to claim 1, wherein the tin oxide fine particles contain a tungsten element. 3. The image forming method according to claim 1, wherein the tin oxide fine particles are present on the surface of toner particles containing at least a binder resin and a colorant. 4. The tin oxide fine particles have a resistance of 1 × 10 5.
The image forming method according to claim 1, wherein the image forming method is ² Ωcm or more and less than 1 × 10 ⁹ Ωcm. 5. The tin oxide fine particles have a volume average particle size smaller than the volume average particle size of the toner particles and have a volume average particle size of 0.
The image forming method according to claim 1, wherein the image forming method has a thickness of at least 05 μm. 6. The tin oxide fine particles liberated from the toner particles among the tin oxide fine particles contained in the toner have a liberation rate of 5 to 90%. The image forming method described. 7. The tin oxide fine particles present on the surface of the toner particles are present in a proportion of 0.3 or more per toner particle, according to any one of claims 3 to 6. Image forming method. 8. The image forming method according to claim 1, wherein the tin oxide fine particles are contained in an amount of 0.2 to 10 mass% with respect to the entire toner. 9. The image forming method according to claim 1, wherein the toner contains magnetic iron oxide. 10. The toner has a magnetic field of 79.6 kA / m.
The magnetization intensity at (1000 Oersted) is 10 to
The image forming method according to claim 9, wherein the image forming method is 50 Am ² / kg (emu / g). 11. The toner has an average circularity of 0.97.
It is 0 or more, The image forming method in any one of Claims 1-10 characterized by the above-mentioned. 12. The toner has a weight average particle diameter of 3 to 1.
It is 0 micrometer, The image forming method in any one of Claims 1-11 characterized by the above-mentioned. 13. The image according to claim 1, wherein the photoconductor is an amorphous silicon photoconductor further having a surface layer formed of an amorphous hydrogenated carbon film. Forming method. 14. The image forming method according to claim 13, wherein the amorphous hydrogenated carbon film has a hydrogen content of 41 to 60%. 15. The image forming method according to claim 1, wherein the charging step is a contact charging step of charging the charging member by bringing the charging member into contact with the photosensitive member. 16. The image forming method according to claim 1, wherein, in the charging step, the charging member and the photoconductor are in contact with each other through the tin oxide fine particles. 17. The image forming apparatus according to claim 1, wherein in the developing step, the transfer residual toner remaining on the image bearing member after the transferring step is collected by the toner bearing member. Method. 18. In the charging step, 10 ^{2 to} 5 × 10 ⁵ pieces / mm are provided at a contact portion between the charging member and the image carrier.
18. The image forming method according to claim 1, wherein the image bearing member is charged with the tin oxide fine particles of ² interposed. 19. The image forming method according to claim 1, wherein the developing step is a non-contact developing step in which the image carrier and the toner carrier are in non-contact with each other. . 20. The charging member has an Asker C hardness of 25.
The image forming method according to any one of claims 1 to 19, wherein the image forming method is a roller member of -50 degrees or less. 21. The charging member is a roller member, and the surface of the roller member has an average cell diameter of 5 to 30 in terms of sphere.
The image forming method according to any one of claims 1 to 20, wherein the image forming method has a dent having a size of 0 µm, and a porosity of a roller member surface having the dent as a void is 15 to 90%. 22. The image forming method according to claim 1, wherein the charging member is a brush member having conductivity. 23. An image carrier, charging means for applying a voltage to a charging member to charge the image carrier, and electrostatic latent image forming means for forming an electrostatic latent image on the charged image carrier. Developing means for forming a toner image by transferring the toner carried on the toner carrying body to the electrostatic latent image held on the surface of the image carrying body; and the toner formed on the image carrying body. In an image forming apparatus including at least a transfer unit for electrostatically transferring an image onto a transfer material, the image carrier has a conductive support and a silicon atom provided on the conductive support as a main component. An amorphous silicon-based photoreceptor having a photoconductive layer composed of an amorphous material, wherein the toner has at least a binder resin, a colorant and tin oxide fine particles, and the tin oxide fine particles are based on tin element. 0.1 to 30 mol% An image forming apparatus characterized by containing tungsten element and / or phosphorus. 24. The image forming apparatus according to claim 23, wherein the tin oxide fine particles contain a tungsten element. 25. The image forming apparatus according to claim 23, wherein the tin oxide fine particles are present on the surface of toner particles containing at least a binder resin and a colorant. 26. The tin oxide fine particles have a resistance of 1 × 1.
The image forming apparatus according to any one of claims 23 to 25, which has a value of 0 ² Ωcm or more and less than 1 × 10 ⁹ Ωcm. 27. The tin oxide fine particles have a volume average particle diameter smaller than the volume average particle diameter of the toner particles and are 0.05 μm or more.
27. The image forming apparatus according to any one of 26. 28. Among the tin oxide fine particles contained in the toner, the liberation rate of the tin oxide fine particles released from the toner particles is 5 to 90%.
27. The image forming apparatus according to any one of 27. 29. The tin oxide fine particles present on the surface of the toner particles are present in a proportion of 0.3 or more per toner particle, according to any one of claims 25 to 28. Image forming apparatus. 30. The image forming apparatus according to claim 23, wherein the tin oxide fine particles are contained in an amount of 0.2 to 10 mass% with respect to the entire toner. 31. The image forming apparatus according to claim 23, wherein the toner contains magnetic iron oxide. 32. The toner has a magnetic field of 79.6 kA / m.
The magnetization intensity at (1000 Oersted) is 10 to
The image forming apparatus according to claim 31, wherein the image forming apparatus is 50 Am ² / kg (emu / g). 33. The toner has an average circularity of 0.97.
33. The image forming apparatus according to claim 23, which is 0 or more. 34. The toner has a weight average particle diameter of 3 to 1.
The image forming apparatus according to claim 23, wherein the image forming apparatus has a thickness of 0 μm. 35. The image according to claim 23, wherein the photoconductor is an amorphous silicon photoconductor further having a surface layer formed of an amorphous hydrogenated carbon film. Forming equipment. 36. The image forming apparatus according to claim 35, wherein the amorphous hydrogenated carbon film has a hydrogen content of 41 to 60%. 37. The image forming apparatus according to claim 23, wherein the charging unit is a contact charging unit that charges the photosensitive member by bringing the charging member into contact with the photosensitive member. 38. The image forming apparatus according to claim 23, wherein the charging member of the charging unit and the photoconductor are in contact with each other through the tin oxide fine particles. 39. The developing device is a device for collecting the transfer residual toner remaining on the image carrier after the transfer by the toner carrier, according to any one of claims 23 to 38. Image forming apparatus. 40. The charging means is a means for charging the image carrier in a state where 10 ^{2 to} 5 × 10 ⁵ tin oxide fine particles are present in a contact portion between the charging member and the image carrier. The image forming apparatus according to any one of claims 23 to 39, wherein: 41. The image forming apparatus according to claim 23, wherein the developing unit is a non-contact developing unit in which the image carrier and the toner carrier are in non-contact with each other. . 42. The charging member has an Asker C hardness of 2
The image forming apparatus according to any one of claims 23 to 41, which is a roller member of 5 to 50 degrees or less. 43. The charging member is a roller member, and the surface of the roller member has an average cell diameter of 5 to 30 in terms of sphere.
The image forming apparatus according to any one of claims 23 to 42, wherein the image forming apparatus has a dent having a size of 0 µm, and a porosity of a roller member surface having the dent as a void is 15 to 90%. 44. The image forming apparatus according to claim 23, wherein the charging member is a brush member having conductivity.