JP2002278128A - Toner and method for image formation, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for image formation which begins to electrostatically be charged and suppresses a decrease in image density and a ghost even when used by a very small-sized printer or copying machine. SOLUTION: The magnetic toner used for an image forming method which carries the magnetic toner to a development part facing a latent image carrier by a toner carrier while forming a thin layer of the magnetic toner on the toner carrier, develops a latent image formed on the latent image carrier with the magnetic toner, and satisfies D1/D2<=0.5, D2<=30, and 55<=V, where D2 is the diameter (mm) of the toner carrier and V is the peripheral speed V (mm/ second) of the latent image carrier, is obtained by mixing inorganic particulates after organic processing externally with magnetic toner particles having at least binding resin and magnetic bodies and has particles of >=0.900 in the circularity (a) obtained from circularity a=L0 /L (where L0 is the circumferential length of a circle having the same projection area with a particle image and L is the circumferential length of the particle image) by >=80% in terms of a number based cumulative value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic technique, and is applied to a printer, a copying machine, a facsimile, and the like using an electrostatic toner (hereinafter, referred to as a toner) for visualizing an electrostatic latent image. And a process cartridge.

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
Many methods are known as described in Japanese Patent Application Laid-Open Publication No. Sho 43-24748 and the like. Generally, a photoconductive substance is used, and an electric latent image is formed on a photoreceptor by various means. The latent image is developed with toner, and a toner image is transferred to a transfer material such as paper as necessary, and then fixed by heating, pressure, heating and pressurizing, or solvent vapor to obtain a copy. The toner remaining on the photosensitive member without being transferred is cleaned by various methods, and the above steps are repeated. In recent years, such copying methods have begun to be used not only for copying office work for simply copying original documents, but also for copying high-definition images such as printers or graphic designs as computer outputs. .

As the printer method, LED and LBP printers have become the mainstream in the recent market, and higher resolution is required, and further reduction in size, weight, and speed of the apparatus itself is required. . For this reason, in a small device called a so-called personal printer or the like, there is a demand for further miniaturization of an internal photoconductor and a developing device.

In addition, there has been a demand for improvement in printing speed and image quality while using smaller photoconductors and toner carriers.

The one-component developing system does not require carrier particles such as glass beads or iron powder as in the two-component developing system, so that the developing method itself can be reduced in size and weight. Further, in order to obtain high image quality, the particle size of toner has been reduced.
253, JP-A-1-191156, JP-A-2-214156, JP-A-2-284158, JP-A-3-181952, JP-A-4-162
048 and JP-A-8-184990 propose a toner having a specific particle size distribution and a small particle size.

In order to provide an image forming method and a process cartridge corresponding to a smaller and faster printing apparatus, a high tribo is uniformly held on a toner carrier (developing sleeve) and the toner is used as a photosensitive member. It needs to be developed on top. However, when a conventional toner is used in an ultra-small developing system, the charge amount of the toner cannot be set to a sufficient value due to the small surface area of the toner carrier, and furthermore, the diameter of the toner carrier is reduced. In addition, since the diameter of the latent image carrier is reduced, the developing area of the toner becomes extremely narrow, and a sufficient amount of toner is not developed. For this reason, there has been a demand for an improvement in the image density and the reproducibility of an image composed of fine lines or minute dots, which is likely to decrease.

In particular, such a phenomenon tends to cause poor development in a high-temperature and high-humidity environment, and further causes problems such as a decrease in image density and ghosts after being left for a long period of time, and further improvement is desired. I was

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic toner, an image forming method and a process cartridge which solve the above-mentioned problems.

That is, an object of the present invention is to provide a quick charging start even in a micro printer or copier.
An object of the present invention is to provide an image forming toner, an image forming method, and a process cartridge in which image density reduction and ghost are suppressed.

An object of the present invention is to provide an image forming toner, an image forming method, and a process cartridge which have a high developing efficiency even under a high-temperature and high-humidity environment, provide a sufficient image density, and have high reproducibility of fine lines and fine dots. It is in.

[0011]

According to the present invention, there is provided a toner container, wherein a magnetic toner contained in a developing container is regulated by a toner layer regulating member to form a thin layer of the magnetic toner on the toner carrier. Transports the magnetic toner to a developing section facing the latent image carrier, develops the latent image formed on the latent image carrier with the magnetic toner, and sets the diameter of the toner carrier to D1 (mm), The diameter of the latent image carrier is D2 (m
m), the toner used in the image forming method satisfying D1 / D2 ≦ 0.5, D2 ≦ 30, and 55 ≦ V when the peripheral speed of the latent image carrier is V (mm / sec). The magnetic toner is a magnetic toner in which an organically treated inorganic fine powder is externally added to and mixed with magnetic toner particles having at least a binder resin and a magnetic substance, and has the following formula (1): circularity a = L ₀ / L (1) (where L ₀ represents the circumference of a circle having the same projected area as the particle image, and L represents the circumference of the particle image). The present invention relates to an image forming toner characterized in that the toner has an accumulated value of 80% or more based on the number.

Further, according to the present invention, the magnetic toner accommodated in a developing container is regulated by a toner layer regulating member, and a thin layer of the magnetic toner is formed on the toner carrier while the magnetic toner is controlled by the toner carrier. To a developing section facing the latent image carrier, and developing the latent image formed on the latent image carrier with the magnetic toner, wherein the diameter of the toner carrier is D1 (mm); The diameter of the latent image carrier is D
2 (mm) and the peripheral speed V of the latent image carrier (mm / sec), D1 / D2 ≦ 0.5, D2 ≦ 30, 55 ≦ V, and the magnetic toner is A magnetic toner in which an inorganic fine powder that has been subjected to an organic treatment is externally added to and mixed with magnetic toner particles having a resin and a magnetic material, and a particle having a circularity a of 0.900 or more determined by the above formula (1). The present invention relates to an image forming method characterized by having a number-based cumulative value of 80% or more.

Further, the present invention is a process cartridge having at least an integrated latent image carrier for carrying a latent image, and a developing container having at least a toner carrier and a toner layer regulating member. The magnetic toner contained in the toner carrier is regulated by a toner layer regulating member, and a thin layer of the magnetic toner is formed on the toner carrier, while the toner carrier carries the magnetic toner to a developing unit facing the latent image carrier. And a process cartridge detachably mountable to the image forming apparatus main body for performing an image forming method for developing the latent image formed on the latent image carrier with the magnetic toner. At the time of image formation, when the diameter of the toner carrier is D1 (mm), the diameter of the latent image carrier is D2 (mm), and the peripheral speed of the latent image carrier is V (mm / sec), D1 / D1 2 ≦ 0.5, D2 ≦ 30,55 ≦ V
Wherein the magnetic toner is a magnetic toner in which an organically treated inorganic fine powder is externally added to magnetic toner particles having at least a binder resin and a magnetic substance, and is obtained from the above formula (1). The present invention relates to a process cartridge characterized in that particles having a circularity a of 0.900 or more have a cumulative value on a number basis of 80% or more.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming method for forming an image by driving a smaller latent image carrier and a toner carrier at a certain speed or higher, and combining a magnetic toner having a specific circularity. Thereby, excellent developability which cannot be achieved conventionally can be obtained.

The circularity in the present invention is used as a simple method for quantitatively expressing the shape of particles. In the present invention, the flow particle image analyzer FPI manufactured by Toa Medical Electronics Co., Ltd.
The measurement was performed using A-1000, and the circularity of the measured particles was determined by the following equation (1).

Circularity a = L ₀ / L (1) (where L ₀ represents the circumference of a circle having the same projected area as the particle image, and L represents the circumference of the particle image.)

The circularity a used in the present invention is an index of the degree of unevenness of the toner particles. When the toner has a perfect spherical shape, the circularity a indicates 1.00, and the circularity decreases as the surface shape becomes more complicated. .

A specific measuring method using the measuring apparatus "FPIA-1000" used in the present invention is as follows.
A surfactant, preferably an alkylbenzene sulfonate, is added in an amount of 0.2 to 0.5 ml as a dispersant, and a measurement sample is added in an amount of about 0.2 to 0.5 g. The suspension in which the sample was dispersed was subjected to ultrasonic waves (50 kHz, 120 W) for 1-3 times.
Irradiation for 1 minute, the concentration of the dispersion liquid was adjusted to 1.2 to 20 thousand particles / μl, and 0.60 μm
The circularity distribution of particles having an equivalent circle diameter of at least m and less than 159.21 μm is measured. In addition, the concentration of the dispersion liquid is set to 1.2 to 2.
By setting the number to 100,000 / μl, it is possible to maintain a particle concentration that can maintain the accuracy of the apparatus.

The outline of the measurement is described in the catalog of FPIA-1000 (June 1995 edition) issued by Toa Medical Electronics Co., Ltd., the operation manual of the measuring apparatus and Japanese Patent Application Laid-Open No. 8-136.
No. 439, which is as follows.

The sample dispersion liquid is passed through a flow path (spread along the flow direction) of a flat and flat flow cell (about 200 μm thick). The strobe and the CC are connected so as to form an optical path that intersects with the thickness of the flow cell.
The D cameras are mounted so as to be located on opposite sides of the flow cell. While the sample dispersion is flowing,
Strobe light is applied at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle is captured as a two-dimensional image having a range parallel to the flow cell. From the two-dimensional image area of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. The circularity of each particle is calculated from the two-dimensional image projection area of each particle and the perimeter of the projected image using the above-described circularity calculation formula.

In the present invention, a magnetic toner having a circularity a of at least 80% in terms of the number-based cumulative value of particles having a circularity a of 0.900 or more has a toner carrier diameter of D1 (mm) and a diameter of the latent image carrier. Is D2 (mm), and the peripheral speed V (mm /
Second), D1 / D2 ≦ 0.5 (preferably 0.2 ≦ D1 / D2 ≦ 0.5), D2 ≦ 30, 55 ≦ V
(Preferably 55 ≦ V ≦ 200), the number of times of contact between the magnetic toner particles and a frictional charging member such as a developing sleeve is increased, and the rise of the charging of the magnetic toner is reduced. Because of the high speed, high developing ability can be obtained even in a high-temperature and high-humidity environment. be able to.

Further, the particles having a circularity a of 0.900 or more of the magnetic toner having a cumulative number of 90% or more and the circularity a of 0.950 or more of the particles having a circularity a of 0.950 or more are 6% or less.
Particles having 7% or more and a circularity a of 0.995 or more have a number-based cumulative value of 8% or more and a circularity a of 0.
When the magnetic toner whose abundance of particles of 995 or more occupies 12% or more of the cumulative value based on the number of particles whose circularity a is 0.950 or more is used, the above-described effects are highly exhibited.

When the number of particles having a circularity a of 0.900 or more of the magnetic toner is less than 80% in terms of the number-based cumulative value, the rise of the charging of the magnetic toner is delayed, and the developing ability is reduced. However, sufficient image density cannot be obtained, and reproducibility of fine lines and minute dots and ghost phenomenon are deteriorated.

When the magnetic toner particles exhibiting methanol wettability of the present invention are used, they can have a higher charge amount and can be maintained for a long period without changing the charge amount. . In the present invention, it has been found that by controlling the degree of exposure of the magnetic iron oxide on the surface of the magnetic toner, it is possible to produce a magnetic toner exhibiting excellent developability in a smaller and higher-speed machine.

That is, if the magnetic toner has a certain degree of wettability (hydrophobicity) with respect to the aqueous solution of the polar organic solvent, the material composition on the surface is in an appropriate state and good image characteristics can be obtained.

In the present invention, with respect to the transition of the concentration of methanol in the aqueous methanol solution under specific conditions, the wetting (degree of sedimentation) of the magnetic toner with respect to methanol was measured by transmittance. Examples of toner raw materials that affect the wettability to methanol (hydrophobicity to water) include resins, waxes, magnetic iron oxides, and charge control agents. Among them, as the one that particularly affects the hydrophobic property, the amount of the resin on the surface and the magnetic iron oxide greatly affects the hydrophobic property. For example, when a large amount of magnetic iron oxide is present on the surface of the magnetic toner, the magnetic iron oxide is hydrophilic, and thus the degree of hydrophobicity (methanol wettability) of the entire magnetic toner is low. That is, the magnetic toner is easily wetted at a low methanol concentration.

On the other hand, when a large amount of resin is present on the surface of the magnetic toner, since the resin is highly hydrophobic, the degree of hydrophobicity (methanol wettability) of the entire magnetic toner is high, and when the methanol concentration is high. The magnetic toner becomes easily wet.

Therefore, magnetic toner particles whose methanol dropping curve under certain conditions satisfies specific requirements exhibit excellent charging characteristics even in a high temperature and high humidity environment.

The transmittance curve is obtained by adding a specific amount of magnetic toner particles to a specific concentration of aqueous methanol solution to prepare a sample solution for measuring the hydrophobic property of the magnetic toner particles. The change is measured by using an apparatus configured to continuously measure the change in the transmittance of the sample solution when methanol is added at a dropping rate. The magnetic toner having the wettability of the magnetic toner particles to the aqueous methanol solution whose transmittance curve satisfies the specific requirements is the magnetic toner of the present invention, and the surface of the raw material constituting the magnetic toner particles. Varies depending on the state of exposure. Therefore, when producing a magnetic toner, the magnetic toner of the present invention can be obtained by knowing these types and properties and selecting a production method corresponding to them.

In the magnetic toner of the present invention, the hydrophobic property of the magnetic toner particles was measured by a methanol drop transmittance curve obtained by the wettability to methanol, and the methanol concentration of the methanol aqueous solution when the transmittance was 80% was 6%.
0 to 75%, and the lowest point of the transmittance of the transmittance curve with the methanol concentration of the aqueous methanol solution on the X axis and the transmittance on the Y axis is in the range of 65 to 80%. In this case, since the magnetic toner is a magnetic toner composed of magnetic toner particles having a proper state of magnetic iron oxide on the surface of the magnetic toner, the absolute value of the charge amount is high, and a constant charge amount can be maintained over a long period of time. Excellent developability can be exhibited in a high temperature and high humidity environment.

As an apparatus for measuring a methanol drop transmittance curve of the present invention, for example, a methanol drop transmittance curve measured under the following conditions and procedures using a powder wettability tester WET-100P manufactured by Resca Co., Ltd. Use First, a 70 ml hydrated methanol solution containing 60% by volume of methanol and 40% by volume of water is placed in a 70 ml container, and the magnetic toner as a sample is sieved through a 150-μm mesh into the container. 2 g is precisely weighed and added to prepare a sample liquid for measuring the hydrophobic property of the magnetic toner. Next, the transmittance was measured with light having a wavelength of 780 nm while continuously adding methanol to the sample liquid for measurement at a dropping rate of 1.3 ml / min, and the methanol drop transmittance curve as shown in FIG. 1 was obtained. Create At this time,
The reason why methanol was used as the titration solvent is that the influence of the elution of dyes, pigments, charge control agents and the like contained in the magnetic toner particles is small, and the surface state of the magnetic toner is more accurately observed.

When measured under the above conditions, the transmittance curve is 8
The methanol concentration shown at 0% and at the lowest point was defined. The methanol concentration indicated when the transmittance is 80% corresponds to the degree of hydrophobicity of the magnetic toner particles having the lower degree of hydrophobicity in the entire magnetic toner. The lowest point of the transmittance curve represents the degree of hydrophobicity in which all the magnetic toners are wetted by the methanol concentration, and corresponds to the degree of hydrophobicity indicated by the magnetic toner particles having the highest degree of hydrophobicity. Also,
The behavior from the starting point of the transmittance curve where the transmittance starts to decrease (the point where the magnetic toner particles that start to wet) to the lowest point (the point where all the magnetic toner particles wet) knows the distribution of the hydrophobicity of the magnetic toner. Can be.

In the magnetic toner of the present invention, the methanol drop transmittance curve obtained by the method for measuring the hydrophobic property of specific magnetic toner particles shows that the methanol concentration is within the range of 60 to 75% when the transmittance is 80%. In this case, the magnetic iron oxide on the surface of the magnetic toner particles is appropriately covered, the amount of the magnetic iron oxide is appropriate, and the absolute value of the tribo becomes high. More preferably, the methanol wettability at 80% is 62 to 7%.
When it is 2%, and more preferably when it is 65 to 70%, the state of the magnetic iron oxide present on the surface is appropriate. As a result, the saturation value of the charge amount is high, the charge amount once held can be held for a long time, and a high image density can be obtained.

The lowest point of the transmittance of the curve which can be drawn with the methanol concentration on the X axis and the transmittance on the Y axis is 65 to 80%.
Within this range, a certain amount of magnetic iron oxide is present on the surface of all magnetic toner particles. That is, the amount of magnetic iron oxide on the surface of the magnetic toner particles is most appropriate when the lowermost point of the transmittance curve is preferably 67 to 77%, and more preferably when the lowest point of the transmittance curve is 69 to 75%. It can be said that the average amount of magnetic iron oxide is the same.
Thus, by measuring the methanol concentration near where the magnetic toner particles start to wet the methanol and the methanol concentration at the end of the wetting, the index of the hydrophobicity of the magnetic toner particle surface and the overall magnetic toner particle The hydrophobicity distribution can be grasped, and thus the quality of the magnetic toner can be monitored.

A mechanical pulverizer preferably used as a pulverizing means used in the method for producing a magnetic toner of the present invention will be described. Examples of the mechanical pulverizer include a pulverizer KTM and Kryptron manufactured by Kawasaki Heavy Industries, Ltd., and a turbo mill manufactured by Turbo Kogyo Co., Ltd. These apparatuses can be used as they are or after being appropriately improved. preferable.

An embodiment of a method for producing a toner having a more specific circularity according to the present invention will be described. In the method for producing a toner of the present invention, a mixture of toner constituent materials is melt-kneaded, and after the obtained kneaded product is cooled, a coarsely pulverized product obtained by pulverizing the cooled product by a pulverizing means is used as a powder material. used. Then, first, a rotor which is a rotating body having a predetermined amount of the pulverized raw material attached to at least the center rotating shaft, and a stator which is arranged around the rotor while keeping a constant interval from the rotor surface. By introducing into a mechanical crusher that is configured so that an annular space formed by maintaining the distance and having an airtight state, and rotating the rotor of the mechanical crusher at a high speed. Finely pulverize the object. Next, the finely pulverized raw material is introduced into a classification step and classified to obtain a classified product as a toner raw material composed of a group of particles having a specified particle size. At this time, in the classification step, a multi-divided airflow classifier having at least a coarse powder region, a medium powder region, and a fine powder region is preferably used as a classification means. For example, when a three-split airflow classifier is used, the powder raw material is classified into at least three types of fine powder, medium powder, and coarse powder. In the classification process using such a classifier, a coarse powder composed of a group of particles having a larger particle size than the preferred particle size and a fine powder composed of a group of particles having a particle size smaller than the preferred particle size are removed, and the medium powder is used as it is as a toner product. Or after being mixed with an external additive such as hydrophobic colloidal silica, it is used as a toner. Fine powder composed of particles having a particle size smaller than the preferred particle size classified in the classification step is generally supplied to a melt-kneading step for producing a powder raw material composed of a toner material to be introduced into a pulverizing step. To be reused or discarded. Also,
Ultrafine powder having a smaller particle diameter than the above fine powder and slightly generated in the pulverizing step and the classifying step is similarly supplied to the melt-kneading step and reused or discarded.

An example of a mechanical pulverizer preferably used in the preferred embodiment of the method for producing a toner having a specific circularity according to the present invention will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view of an example of a mechanical pulverizer used in the present invention. FIG. 3 is a schematic cross-sectional view taken along the line DD ′ in FIG.
Shows a perspective view of the rotor 314 shown in FIG. As shown in FIG. 2, the device has a large number of grooves on a high-speed rotating surface including a casing 313, a jacket 316, a distributor 220, and a rotating body mounted on a central rotating shaft 312 in the casing 313. The rotor 314 provided, the stator 310 provided with a large number of grooves on the surface arranged at regular intervals on the outer periphery of the rotor 314, and a raw material input for introducing a raw material to be processed An outlet 311 and a raw material discharge port 302 for discharging the powder after the processing are provided. The crushing operation of the cane-type crusher configured as described above is performed, for example, as follows.

That is, when a predetermined amount of powder material is introduced from the powder inlet 311 of the mechanical pulverizer shown in FIG. 2, the particles are introduced into the pulverization processing chamber, where the particles are rotated at a high speed. Rotor 314 having a large number of grooves on the surface
And the stator 310 having a large number of grooves formed on the surface thereof, and the instantaneous pulverization caused by a number of super-high-speed vortices generated behind the high-frequency vortex and the high-frequency pressure vibration generated thereby. . After that, it is discharged through the raw material discharge port 302. The air (air) carrying the toner particles passes through the pulverization processing chamber, and is supplied to the raw material discharge port 302, the pipe 219, the collection cyclone 229, and the bag filter 2.
22 and is discharged out of the system of the apparatus system through the suction blower 224. In the present invention, the pulverization of the powdery raw material is performed in this manner, so that a desired pulverization treatment can be easily performed without increasing fine powder and coarse powder.

Further, the peripheral speed of the tip of the rotor 314 to be dried is minimized in the short path, and the load on the apparatus and the excessive surface modification due to the heat of the excessively pulverized toner during the pulverization and the fusing in the machine are avoided. However, in consideration of improving productivity, it is preferably 80 to 180 m / sec, more preferably 90 to 170 m / sec, and still more preferably 100 to 160 m / sec.

The minimum distance between the rotor 314 and the stator 310 is preferably 0.5 to 10.0 mm, more preferably 1.0 to 5.0 mm, and still more preferably 1.0 to 5.0 mm. It is preferable that the thickness is 3.0 mm, whereby insufficient pulverization of the toner and excessive pulverization can be suppressed, and the pulverized raw material can be efficiently pulverized.

Normally, when the pulverized raw material is pulverized with a mechanical pulverizer, the temperature T1 of the spiral chamber 212 and the temperature T2 of the rear chamber 320 of the mechanical pulverizer are controlled, and the pulverization is performed at a temperature equal to or lower than the resin Tg. And a method in which surface modification is not performed at all is selected. However, in order to obtain a magnetic toner having the above-described properties, the temperature of the outlet 302 is set to -10 ° C. to +
Set at 5 ° C, and in the actual pulverized state, Tg of -5 to +10
Preferably, the temperature is in ° C.

Specifically, the room temperature T1 of the spiral chamber in the crusher
Is set to 0 ° C. or lower, more preferably −5 to −20 ° C., generation of excessive heat can be suppressed, and the pulverized raw material can be efficiently pulverized. The temperature difference ΔT (T2−T1) between the room temperature T1 of the spiral chamber 212 and the room temperature T2 of the rear chamber 320 of the mechanical pulverizer is preferably 30 to 80 ° C., more preferably 35 to 75 ° C., and still more preferably. 3
By setting the temperature to 7 to 72 ° C., the resin covers a part of the magnetic iron oxide existing on the surface of the magnetic toner after the pulverization. By creating this surface state, it is possible to obtain a magnetic toner having a high absolute value of tribo and high charging performance. Since it is difficult to determine the surface state of the magnetic toner manufactured in this way only by local surface observation, there is a method of monitoring the hydrophobic property of the magnetic toner by wettability of a certain amount of the magnetic toner with methanol. Since the holding and discharging of the static electricity is performed at the interface between the moisture in the air and the surface of the magnetic toner, it is most suitable for capturing the state of charging and discharging given by the surface state of the magnetic toner.

The magnetic toner particles used in the present invention have a weight average diameter of 5.0 to 10.0 μm. Furthermore, 5.5 to 9.0 μm, particularly 6.0 to 8.0.
It is desirable that the weight average particle diameter is μm.

The resin composition according to the present invention has a glass transition temperature (Tg) of 45 to 80 ° C., preferably 50 to 70 ° C., from the viewpoint of storage stability.

As a method for measuring the glass transition temperature of the resin of the present invention, a differential thermal analysis measuring device (DSC measuring device),
It can be measured using DSC-7 (manufactured by PerkinElmer) under the following conditions.

<Method of measuring glass transition temperature of resin> Sample: 0.5 to 2 mg, preferably 1 mg Temperature curve: Heating I (20 ° C to 180 ° C, heating rate 10 ° C)
/ Min) Temperature drop I (180 ° C to 10 ° C, temperature drop rate 10 ° C / min) Temperature rise II (10 ° C to 180 ° C, temperature rise rate 10 ° C / mi)
n) Measurement method: Put the sample in an aluminum pan and use an empty aluminum pan as a reference. The intersection of the line at the midpoint of the base line before and after the endothermic peak appeared and the differential heat curve was defined as the glass transition point Tg.

Further, the binder resin component used in the present invention is T
In the molecular weight distribution of the HF-soluble component measured by GPC, a low molecular weight polymer having at least one peak in a molecular weight range of 3,000 to 50,000;
It is preferable to be composed of a high molecular weight polymer having at least one peak or shoulder in the range of 0000 to 10,000,000.

These binder resin components can be mixed and dispersed in advance with a wax component before producing a magnetic toner. In particular, a method in which the wax component and the high molecular weight polymer are preliminarily dissolved in a solvent during the production of the binder, and then mixed with the low molecular weight polymer solution is preferable. By mixing the wax component and the high molecular weight component in advance, the phase separation in the micro region is reduced, the high molecular weight component is not re-aggregated, and a good dispersion state with the low molecular weight component can be obtained.

In the present invention, the toner or the binder resin
The molecular weight distribution by GPC using THF (tetrahydrofuran) as a solvent is measured under the following conditions.

The column was stabilized in a heat chamber at 40 ° C., and THF was used as a solvent at this temperature.
At a flow rate of 1 ml / min.
Measure by injecting 0 μl. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the count number. As a standard polystyrene sample for preparing a calibration curve, for example, Tosoh Corporation or Showa Denko KK having a molecular weight of about 10 ² to 10 ⁷ is used, and it is appropriate to use a standard polystyrene sample of at least about 10 points. . An RI (refractive index) detector is used as the detector. As the column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, Shodex GPCKF-801, 802, 803, 8 manufactured by Showa Denko KK
04,805,806,807,800P, TSKgelG1000H (H _XL ) manufactured by Tosoh Corporation,
_{G2000H (H XL), G3000H (} H XL), G40
_{00H (H XL), G5000H (} H XL), G6000H
(H _XL ), G7000H (H _XL ), TSKguardc
column can be mentioned.

The sample is prepared as follows.

After placing the sample in THF and leaving it for several hours,
Shake well and mix well with THF (until the sample is no longer united) and let sit for at least 12 hours. At this time, THF
The time for which the sample is left inside is set to 24 hours or more. Thereafter, the sample processing filter (pore size 0.
45 to 0.5 μm, for example, Mysholidisk H-25
-5 (manufactured by Tosoh Corporation, Exiclodisc 25CR manufactured by Germanic Science Japan) can be used as a GPC measurement sample. The sample concentration is adjusted so that the resin component is 0.5 to 5 mg / ml.

As the binder resin of the toner according to the present invention,
Styrene such as polystyrene and polyvinyltoluene and its substituted homopolymer; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene- Ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate Copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer , Styrene-pig Styrene-based copolymers such as ene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, Polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, paraffin Wax, carnauba wax and the like can be used alone or in combination. Among them, styrene-based copolymers, particularly styrene-acrylic-based copolymers, polyester resins, and mixtures thereof are preferable in view of development characteristics and fixing properties. The binder resin in the present invention is 1 to
It preferably has an acid value in the range of 100 mgKOH / g. Particularly preferred is a resin having an acid value of 1 to 70 mgKOH / g.

Further, as a fixing aid in the toner of the present invention, a hydrocarbon wax, an ethylene-based olefin polymer, or the like may be used together with a binder resin.

The following are examples of the wax used in the present invention. For example, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax Or a block copolymer thereof; a plant wax such as candelilla wax, carnauba wax, wood wax, jojoba wax; an animal wax such as beeswax, lanolin, and whale wax; a mineral wax such as ozokerite, ceresin, and petrolactam. Waxes; waxes mainly containing aliphatic esters such as montanic acid ester wax and caster wax; and those obtained by partially or entirely deoxidizing aliphatic esters such as deoxidized carnauba wax. . Further, saturated straight-chain fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a longer-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and barinaric acid; stearyl alcohol Saturated alcohols such as eicosyl alcohol, behenyl alcohol, kaunavir alcohol, seryl alcohol, melisyl alcohol, or alkyl alcohols having a longer chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amide, oleic acid amide;
Aliphatic amides such as lauric acid amide; saturated aliphatic bisamides such as methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide; ethylenebisoleic acid amide, hexamethylenebisolein Acid amide, N, N′-dioleyladipamide, N, N
Unsaturated fatty acid amides such as N'-dioleyl sebacamide; m-xylene bisstearic acid amide;
Aromatic bisamides such as N'-distearyl isophthalamide; aliphatic metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as metallic soaps); aliphatic hydrocarbons Wax grafted with a vinyl monomer such as styrene or acrylic acid on wax; partially esterified product of fatty acid and polyhydric alcohol such as behenic acid monoglyceride; having hydroxyl group obtained by hydrogenating vegetable oil or fat Methyl ester compounds are mentioned.

These waxes may be obtained by sharpening the molecular weight distribution using a press sweating method, a solvent method, a recrystallization method, a vacuum distillation method, a supercritical gas extraction method or a liquid crystal deposition method, or a low molecular weight solid fatty acid. Also, those from which low-molecular-weight solid alcohols, low-molecular-weight solid compounds, and other impurities have been removed are preferably used.

As the magnetic material used in the present invention, magnetic iron oxide is used. As the magnetic iron oxide, iron oxide such as magnetite, maghemite, and ferrite is used.
Those containing a non-ferrous element on the surface or inside of the magnetic iron oxide are preferred.

The magnetic iron oxide according to the present invention comprises a binder resin 1
It is preferably contained in an amount of 20 to 200 parts by mass with respect to 00 parts by mass. More preferably, the content is preferably 50 to 120 parts by mass.

The magnetic iron oxide used in the present invention preferably contains 0.05 to 10% by mass of a different element based on the iron element. Particularly preferably, the content is 0.2 to 5% by mass.

The different element is preferably an element selected from magnesium, aluminum, silicon, phosphorus and sulfur. Also, lithium, beryllium, boron, germanium, titanium, zirconium,
Tin, lead, zinc, calcium, barium, scandium,
Vanadium, chromium, manganese, cobalt, copper, nickel, gallium, cadmium, indium, silver element, palladium, gold, mercury, platinum, tungsten, molybdenum,
Niobium, osmium, strontium, yttrium,
Metals such as technetium are exemplified.

[0061] These magnetic iron oxides have a number average particle size of 0.1.
Preferably from 0.5 to 1.0 μm, more preferably from 0.2 to 0.5 μm
m is preferred. Magnetic iron oxide has a BET specific surface area of 2
の も の 40 m ² / g (more preferably 4 to ²⁰ m ² / g) are preferably used. There is no particular limitation on the shape,
Any shape is used. As the magnetic characteristics, the saturation magnetization is 10 to 200 Am under a magnetic field of 795.8 kA / m.
² / kg (more preferably, 70-100 Am ² / k
g), the residual magnetization is 1 to 100 Am ² / kg (more preferably, ^{2 to 20} Am ² / kg), and the coercive force is 1 to 30 kA.
/ M (more preferably, 2 to 15 kA / m) is preferably used. The amount of the element in the magnetic iron oxide can be measured by performing a fluorescent X-ray analysis using a fluorescent X-ray analyzer SYSTEM3080 (manufactured by Rigaku Denki Kogyo Co., Ltd.) in accordance with JIS K0119 general rules for fluorescent X-ray analysis. .

The number average diameter of the magnetic substance can be determined by measuring a photograph enlarged by a transmission electron microscope with a digitizer or the like. The magnetic properties of the magnetic material
This is a value measured using an "oscillating sample magnetometer VSM-3S-15" (manufactured by Toei Kogyo Co., Ltd.) under an external magnetic field of 795.8 kA / m. The specific surface area is obtained by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device Autosoap 1 (manufactured by Yuasa Ionics) according to the BET method, and calculating the specific surface area using the BET multipoint method.

In some cases, the magnetic iron oxide used in the magnetic toner of the present invention may be treated with a silane coupling agent, a titanium coupling agent, titanate, aminosilane, or the like.

As the inorganic fine powder used in the toner of the present invention, known inorganic fine powders are used, and silica, alumina, and silica are used to improve the charge stability, developability, fluidity, and storage stability.
It is preferable to be selected from titania or a composite oxide thereof. Furthermore, silica is more preferable. For example, as the silica, both a so-called dry method produced by vapor phase oxidation of a silicon halide and an alkoxide, and a so-called wet silica produced from an alkoxide, a water glass and the like, and a dry silica called a fumed silica can be used. However, dry silica having less silanol groups on the surface and in the interior of the silica fine powder and having less production residues such as Na ₂ O and SO ₃ ^2- is preferred. In the case of fumed silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the manufacturing process. Is also included.

[0065] Inorganic fine powder used in the present invention is the specific surface area by nitrogen adsorption measured by BET method is 30 m ² / g or more, particularly given good results in the range of 50 to 400 m ² / g, the toner 100 mass It is particularly preferable to use 0.2 to 8 parts by mass, preferably 0.5 to 5 parts by mass, and more preferably more than 1.0 to 3.0 parts by mass of silica fine powder with respect to parts. The inorganic fine powder used in the present invention preferably has a primary particle size of 30 nm or less.

Further, the inorganic fine powder used in the present invention is:
Silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, silane coupling agents, silane coupling agents having functional groups, other organosilicon compounds, organotitanium compounds, etc. It is treated with a treating agent or in combination with various treating agents.

For example, as a silane coupling agent,
For example, typically, dimethyldichlorosilane, trimethylchlorosilane, allyldimethylchlorosilane, hexamethyldisilazane, allylphenyldichlorosilane, benzyldimethylchlorosilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyl Examples include triacetoxysilane, divinylchlorosilane, dimethylvinylchlorosilane and the like. The silane coupling agent treatment of the inorganic fine powder is performed by a dry process in which a vaporized silane coupling agent is reacted with a cloud of the inorganic fine powder by stirring or the like, or a silane cup in which the inorganic fine powder is dispersed in a solvent. The treatment can be performed by a generally known apparatus such as a wet method in which a ring agent is dropped and reacted.

It is particularly preferable that the inorganic fine powder used in the present invention is further treated with at least silicone oil.

The oil treatment amount of the silicone oil-treated inorganic fine powder is preferably from 1 to 30% by mass, and particularly preferably from 1 to 20% by mass, based on the treated inorganic fine powder. A preferred range of the amount of the silicone oil-treated inorganic fine powder added to the toner is 0.3 to 3.0% by mass,
Particularly, 0.5 to 2% by mass is preferable. Furthermore, the oil viscosity of the silicone oil is preferably 1 to 10000 mm
² / s, and 50 to 1000 mm ² / s,
More preferred.

Examples of the silicone oil include dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil. A known technique is used for the apparatus for treating the silicone oil. For example, the silica fine powder and the silicone oil may be directly mixed by using a mixer such as a Henschel mixer, or a device for spraying the silicone oil onto the base silica may be used. good. Alternatively, it may be prepared by dissolving or dispersing silicone oil in an appropriate solvent, mixing with a base silica fine powder, and removing the solvent.

In the toner of the present invention, other additives such as lubricant powders such as Teflon (registered trademark) powder, zinc stearate powder, and polyvinylidene fluoride powder; Abrasives such as powder, silicon carbide powder and strontium titanate powder; fluidity-imparting agents such as titanium oxide powder and aluminum oxide powder; anti-caking agents; or conductive materials such as carbon black powder, zinc oxide powder and tin oxide powder. A small amount of a property imparting agent or organic and inorganic fine particles of opposite polarity can also be used as a developing property improver.

The toner of the present invention preferably contains a charge control agent. The following compounds can be used to control the toner to be negatively charged. An organic metal complex and a chelate compound are effective, and examples thereof include a metal complex of a monoazo metal complex, an acetylacetone metal complex, an aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives of bisphenol.

Among them, azo metal complexes represented by the following formula (I) are preferred.

[0074]

Embedded image [Wherein, M represents a coordination center metal, and Sc, Ti, V, C
r, Co, Ni, Mn or Fe. Ar is an aryl group, is an aryl group such as a phenyl group and a naphthyl group, and may have a substituent. In this case, the substituent includes a nitro group, a halogen group, a carboxyl group,
Anilide group and alkyl group having 1 to 18 carbon atoms, 1 carbon atom
There are ~ 18 alkoxy groups. X, X ', Y and Y' are -O-, -CO-, -NH-, -NR- (R is
To 4 alkyl groups). C ⁺ represents a counter ion, and represents hydrogen, sodium, potassium, ammonium, aliphatic ammonium or a mixed ion thereof. ]

In particular, the central metal is preferably Fe or Cr, the substituent is preferably a halogen, an alkyl group or an anilide group, and the counter ion is preferably hydrogen, alkali metal, ammonium or aliphatic ammonium. A mixture of complex salts having different counter ions is also preferably used.

The following compounds control the toner to be positively charged. Nigrosine modified products such as nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and phosphonium salts which are analogs thereof Onium salts and their lake pigments; triphenylmethane dyes and these lake pigments, (phosphor tungstic acid, phosphomolybdic acid,
Phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.); metal salts of higher fatty acids; dibutyltin oxide;
Diorganotin oxides such as dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; guanidine compounds; and imidazole compounds. These can be used alone or in combination of two or more. Among these, a triphenylmethane compound and a quaternary ammonium salt whose counter ion is not halogen are preferably used. The following formula (II)

[0077]

Embedded image [In the formula, R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably, C1 to C4). And a copolymer with a polymerizable monomer such as styrene, acrylate or methacrylate described above can be used as the positive charge control agent. In this case, the homopolymer and the copolymer have a function as a charge control agent and a function as (all or part of) a binder resin.

As a method for incorporating the charge control agent into the toner, there are a method of adding the charge control agent inside the toner particles and a method of adding the charge control agent externally. The use amount of these charge control agents is determined by the type of the binder resin, the presence or absence of other additives, the toner manufacturing method including the dispersion method, and is not limited to a specific one. Preferably it is used in the range of 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, based on 100 parts by mass of the binder resin.

To prepare the toner according to the present invention, a binder resin, a pigment, a dye or a magnetic substance as a colorant, a charge controlling agent, and other additives are sufficiently mixed by a mixer such as a ball mill. Using a hot kneader such as a heating roll, kneader or extruder, melt or knead and knead the meat to make the resins compatible with each other and disperse or dissolve the pigment or dye. The toner according to the present invention can be obtained by performing an appropriate classification.

One preferred embodiment of the image carrier used in the present invention will be described below (see FIG. 9).

Examples of the conductive substrate include metals such as aluminum and stainless steel, aluminum alloys and indium oxide.
Cylindrical cylinders and films of plastic having a coating layer of a tin oxide alloy or the like, paper impregnated with conductive particles, plastic, plastic having a conductive polymer, and the like are used.

On these conductive substrates, improvement of the adhesion of the photosensitive layer, improvement of coating properties, protection of the substrate, coating of defects on the substrate,
An undercoat layer may be provided for the purpose of improving the charge injection property from the substrate, protecting the photosensitive layer against electrical destruction, and the like. The undercoat layer is made of polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymerized nylon, glue,
It is formed of a material such as gelatin, polyurethane, and aluminum oxide. The film thickness is usually 0.1 to 10 μm,
Preferably it is about 0.1 to 3 μm.

The charge generation layer is made of an azo pigment, a phthalocyanine pigment, an indigo pigment, a perylene pigment, a polycyclic quinone pigment, a squarylium dye, a pyrylium salt, a thiopyrylium salt, a triphenylmethane dye, selenium,
A charge generating substance such as an inorganic substance such as amorphous silicon is dispersed in an appropriate binder and formed by coating or vapor deposition. The binder can be selected from a wide range of binder resins, for example, polycarbonate resin, polyester resin, polyvinyl butyral resin, polystyrene resin, acrylic resin, methacryl resin, phenol resin, silicone resin, epoxy resin, vinyl acetate resin, etc. Is mentioned. The amount of the binder contained in the charge generation layer is 80% by mass.
Hereinafter, it is preferably selected from 0 to 40% by mass. Further, the thickness of the charge generation layer is preferably 5 μm or less, particularly preferably 0.05 to 2 μm.

The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transporting layer is formed by dissolving a charge transporting substance in a solvent together with a binder resin if necessary, and applying the solution. The film thickness is generally 5 to 40 μm. As the charge transport substance, biphenylene,
Polycyclic aromatic compounds having a structure such as anthracene, pyrene, and phenanthrene; nitrogen-containing cyclic compounds such as indole, carbazole, oxadiazole, and pyrazoline;
Hydrazone compounds, styryl compounds, selenium, selenium
Tellurium, amorphous silicon, cadmium sulfide and the like. Examples of the binder resin for dispersing these charge transporting substances include resins such as polycarbonate resin, polyester resin, polymethacrylate, polystyrene resin, acrylic resin, polyamide resin, and organic resins such as poly-N-vinylcarbazole and polyvinylanthracene. Photoconductive polymers and the like can be mentioned.

Further, a protective layer may be provided as a surface layer. As the resin for the protective layer, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent of these resins alone or
It is used in combination of more than one species.

Further, conductive fine particles may be dispersed in the resin of the protective layer. Examples of the conductive fine particles include metals, metal oxides, etc., preferably, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide-coated titanium oxide, tin-coated indium oxide, There are ultrafine particles such as antimony-coated tin oxide and zirconium oxide. These may be used alone or as a mixture of two or more. Generally, when particles are dispersed in the protective layer, it is necessary that the particle diameter of the particles is smaller than the wavelength of the incident light in order to prevent scattering of the incident light by the dispersed particles, and the particles are dispersed in the protective layer in the present invention. The particle size of the conductive and insulating particles is preferably 0.5 μm or less. The content in the protective layer is preferably from 2 to 90% by mass, more preferably from 5 to 80% by mass, based on the total mass of the protective layer. The thickness of the protective layer is preferably from 0.1 to 10 μm, more preferably from 1 to 7 μm. The coating of the surface layer can be performed by spray coating, beam coating or permeation coating of the resin dispersion.

An example of the image forming apparatus of the present invention is schematically shown in FIG. 5, and an image forming method will be described based on the schematic.

Reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member, around which a charging roller 2 having primary charging means, an exposure optical system 3, a developing means 4 having a toner carrier 5, a transferring means 9, and a cleaning blade 11 are provided. Is arranged. In this image forming apparatus, the surface of the photoconductor 1, which is a photoconductor, is uniformly charged by the charging roller 2, and is then exposed by the exposure optical system 3 to form an electrostatic latent image on the surface of the photoconductor 1.

As for the voltage applied to the charging roller, the DC voltage is preferably 200 to 2000 V in absolute value, and the AC voltage has a peak-to-peak voltage of 400 to 4000 V.
Preferably, the frequency is between 200 and 3000 Hz.

Next, a toner coat layer is formed by a toner layer thickness regulating member 6 on the surface of the toner carrier 5 containing a magnet, and the conductive member of the photosensitive member 1 and the toner carrier 5 are formed in the developing section. The electrostatic latent image formed on the photoreceptor 1 is developed while applying an alternating bias, a pulse bias, and / or a DC bias by the bias applying unit 8 therebetween.
In the figure, 7 is a stirring means, and 13 is a magnetic toner.

The developed toner image is conveyed to the transfer paper P, and a transfer roller 9 as a transfer means and a voltage application means 10 are applied with a charge having a polarity opposite to that of the toner from the back surface of the transfer paper P. Is electrostatically transferred to

The transfer paper P on which the toner image has been transferred passes through the heating and pressing roller fixing device 12, and the toner image becomes a fixed image.

The transfer residual toner remaining on the photoreceptor after the transfer step is removed by the cleaning blade 11 as a cleaning means and collected by the cleaner 14, and the steps below the primary charging are repeated again.

In the process cartridge of the present invention, a plurality of components such as the above-described drum-shaped photosensitive member, developing device, and cleaning means are integrally connected as an apparatus unit to constitute a process cartridge. The cartridge is configured to be detachable from the apparatus main body. For example, a process device is formed by integrally supporting a charging roller, a developing device, and a cleaning device on which a cleaning blade is mounted together with a photoreceptor, as a single unit detachable from the apparatus main body, and a guide means such as a rail of the apparatus main body. It may be configured to be detachable by using.

FIG. 6 shows an embodiment of the process cartridge of the present invention. In the present embodiment, a process cartridge 16 in which the developing means 4, the drum-shaped photosensitive member 1, the cleaner 14 having the cleaning blade 11, and the charging roller 2 are integrated is exemplified. In this process cartridge, when the magnetic toner 13 of the developing means 4 runs out, it is replaced with a new cartridge.

In this embodiment, the developing means 4 is the magnetic toner 1
3, a predetermined electric field is formed between the photosensitive member 1 and the developing sleeve 5 as a toner carrier during development. The distance between the photoconductor and the developing sleeve 5 is very important for the development step to be performed appropriately.

In the process cartridge shown in FIG. 6, the developing means 4 includes a toner container 15 for storing the magnetic toner 13 and the magnetic toner 13 in the toner container 15 from the toner container 15 to the developing area facing the photoreceptor 1. And a resilient blade 6 as a toner layer thickness regulating member for regulating the magnetic toner conveyed to the developing area to a predetermined thickness and forming a thin toner layer on the developing sleeve. Having. As the toner layer thickness regulating member, a magnetic blade may be provided with a gap of about 50 to 500 μm with respect to the developing sleeve instead of the elastic blade.

The developing sleeve 5 can have any structure. Usually, it comprises a non-magnetic developing sleeve 5 containing a magnet (not shown). The developing sleeve 5 may be a cylindrical rotating body as shown. Usually, aluminum or SUS is preferably used as the material. The elastic blade 6 is formed of a rubber elastic material such as urethane rubber, silicone rubber, or NBR; a metal elastic material such as phosphor bronze or a stainless steel plate; and an elastic plate formed of a resin elastic material such as polyethylene terephthalate or high-density polyethylene. Is done. The elastic blade 6 is in contact with the developing sleeve 5 by the elasticity of the member itself, and is fixed to the toner container 15 by a blade supporting member made of a rigid body such as iron. The elastic blade 6 has a linear pressure of 4.9 to 78.4.
It is preferable that the developing sleeve 5 abuts in the counter direction with respect to the rotation direction of the developing sleeve 5 at N / m (5 to 80 g / cm).

As the primary charging means, the charging roller 2 is used to make contact with the photoreceptor. However, it is preferable in that the generation of ozone due to charging is small. The transfer means has been described using the transfer roller 9, but may be a contact charging means such as a transfer blade, or a non-contact corona transfer means.
A contact charging unit is preferable because ozone is less generated by transfer.

[0100]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples. “Parts” means parts by mass.

Photoconductor Production Example 1 As a photoconductor, an Al cylinder having an outer diameter of about 30 mm was used as a base. Then, layers having the structure shown in FIG. 9 were sequentially laminated by dip coating to produce a photoreceptor 1. (1) Conductive coating layer: Mainly composed of tin oxide and titanium oxide powder dispersed in a phenol resin. 15μ thickness
m. (2) Undercoat layer: mainly composed of modified nylon and copolymerized nylon. The film thickness is 0.6 μm. (3) Charge generation layer: mainly composed of oxytitanium phthalocyanine dispersed in butyral resin. Thickness 0.6
μm. (4) Charge transport layer: mainly composed of a hole-transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight 20,000 according to the Oswald viscosity method) at a mass ratio of 8:10, and a polytetrafluoroethylene powder ( Particle size 0.2μ
m) was added in an amount of 10% by mass based on the total solid content, and the mixture was uniformly dispersed. 24 μm thick.

Photoreceptor Production Example 2 Photoreceptor 2 was produced in the same manner as in Photoreceptor Production Example 1 using an Al cylinder having an outer diameter of about 24 mm as a base.

Photoreceptor Production Example 3 Photoreceptor 3 was produced in the same manner as in Photoreceptor Production Example 1 using an Al cylinder having an outer diameter of about 20 mm as a base.

Developing sleeve production example 1 200 parts of resole type phenol resin solution (containing 50% methanol) 45 parts of graphite having a number average particle diameter of 6.1 μm 5 parts of conductive carbon black 130 parts of isopropyl alcohol 1 mm zirconia beads were added as media particles, dispersed in a sand mill for 2 hours, and the zirconia beads were separated using a sieve to obtain a stock solution.

To 380 parts of the stock solution obtained above, 10 parts of conductive spherical particles (number average particle size: 10 μm) were added, and isopropyl alcohol was added so that the solid content concentration became 30%. The dispersion was performed for 1 hour using glass beads, and the glass beads were separated using a screen to obtain a coating liquid. Using this coating solution, the outer diameter is about 15 by the spray method.
A conductive coating layer was formed on an aluminum cylindrical tube having a thickness of 1 mm, and then heated at 150 ° C. for 30 minutes in a hot-air drying oven to cure the conductive coating layer, thereby producing a developing sleeve 1.

Developing Sleeve Production Example 2 A developing sleeve 2 was produced in the same manner as in Developing Sleeve Production Example 1 using an aluminum cylindrical tube having an outer diameter of about 12 mm.

Developing Sleeve Manufacturing Example 3 A developing sleeve 3 was manufactured in the same manner as in the developing sleeve manufacturing example 1 using an aluminum cylindrical tube having an outer diameter of about 8 mm.

(Toner Production Example 1) Binder resin 100 parts Magnetic iron oxide 95 parts Polypropylene wax 3 parts Charge control agent 2 parts

The binder resin is styrene-acrylic resin (DS
Glass transition temperature Tg by C measurement is 61 ° C., acid value
0 mgKOH / g, peak top P11 by GPC
7000, P2 77000, monomer ratio: styrene 7
2.5 parts, n-butyl acrylate 20 parts, mono-n-
Butyl maleate 7 parts, divinylbenzene 0.5 part); magnetic iron oxide (average particle size: 0.20 μm, BET specific surface area:
8.0 m ² / g, coercive force: 3.7 kA / m, saturation magnetization:
82.3 Am ² / kg, remanent magnetization: 4.0 Am ² / k
g), polypropylene wax (melting point: 143 ° C, 25 ° C)
The iron complex of the monoazo compound shown below was used as the charge control agent.

[0110]

Embedded image

The above compound was melt-kneaded with a twin-screw extruder heated to 130 ° C., and the cooled kneaded product was ground with a hammer mill.

The pulverization was performed using a turbo mill (manufactured by Turbo Kogyo Co., Ltd.), and the air temperature was adjusted based on the conditions shown in Table 1 to perform mechanical pulverization using a turbo mill (manufactured by Turbo Kogyo Co., Ltd.). Ultrafine powder and coarse powder were strictly classified and removed by a multi-division classifier utilizing the Coanda effect (Elbow jet classifier manufactured by Nippon Steel Mining Co., Ltd.) to obtain toner particles 1. The methanol wettability of the toner particles 1 was measured using the measurement method described in the specification. The methanol concentration at a transmittance of 80% was 68%, and the lowest point of the wettability transmittance curve was 72.0%. Table 1 shows toner production conditions and results of wettability, and FIG. 1 shows a transmittance curve of methanol wettability.

Next, 1.2 parts by mass of hydrophobic silica hydrophobicized with hexamethyldisilazane and dimethyl silicone oil was mixed with 100 parts by mass of the toner particles 1 using a Henschel mixer. Toner 1 was obtained. The circularity of the obtained magnetic toner 1 was measured by the method described in the specification. Table 1 shows the physical property values of the magnetic toner 1 thus obtained.

(Toner Production Example 2) Toner particles 2 were obtained by changing the pulverization conditions as shown in Table 1. Table 1 shows the physical property values of the obtained toner particles 2. 1 of the toner particles 2
With respect to 00 parts by mass, 1.2 parts by mass of hydrophobic silica hydrophobized with hexamethyldisilazane and dimethyl silicone oil and 0.6 part by mass of strontium titanate fine powder were mixed with a Henschel mixer, Magnetic toner 2
I got Table 1 shows the physical property values of the magnetic toner 2 thus obtained.

(Toner Production Examples 3 to 6) Pulverization conditions are shown in Table 1.
The toner particles 3, 4, 5, and 6 were obtained in the same manner as in Toner Production Example 2 except that the toner particles were changed as shown in (1). Table 1 shows the physical property values of the obtained toner particles 3, 4, 5, and 6.

(Comparative Production Example 1 of Toner)
The toner particles 7 were obtained in the same manner as in the toner production example 1 except that the toner particles 7 were changed as shown in FIG. Table 1 shows the physical property values of the obtained toner particles 7. Next, 10 of the toner particles 7
Magnetic toner 7 was obtained by mixing 1.2 parts by weight of untreated silica with 0 parts by weight using a Henschel mixer. Table 1 shows the physical property values of the magnetic toner 7 thus obtained.

(Toner Comparative Production Example 2) Pulverization conditions are shown in Table 1.
The toner particles 8 were obtained in the same manner as in the toner production example 1 except for the changes shown in FIG. Table 1 shows the physical property values of the obtained toner particles 8. Next, 10 of the toner particles 8
With respect to 0 parts by mass, 1.2 parts by mass of hydrophobic silica hydrophobized with hexamethyldisilazane and dimethyl silicone oil and 0.6 part by mass of strontium titanate fine powder were mixed with a Henschel mixer, Magnetic toner 8
I got Table 1 shows the physical property values of the magnetic toner 8 thus obtained.

(Comparative Toner Production Example 3) The same raw materials as in Toner Production Example 1 were used at the same mixing ratio, and the raw materials were heated and kneaded, and the kneaded product was roughly pulverized with a hammer mill. Next, after pulverizing with a collision type pulverizer using a jet stream, the obtained finely pulverized material is divided into ultra fine powder and coarse powder by a multi-division classifier using a Coanda effect (Nippon Mining Co., Ltd. elbow jet classifier). Was strictly classified and removed to obtain toner particles 9. Next, 1.2 parts by mass of untreated silica was mixed with 100 parts by mass of the toner particles 9 using a Henschel mixer to obtain a magnetic toner 9. Table 1 shows the physical property values of the magnetic toner 9 thus obtained.

[0119]

[Table 1]

<Embodiment 1> The image forming apparatus shown in FIG. 5 in which the process cartridge shown in FIG.
A 470 (Canon) modified machine was used. Similarly, an EP32 process cartridge (manufactured by Canon) was remodeled as a process cartridge, and the photosensitive member 1 and the developing sleeve 1 were used. As 110%,
Using Toner 1 produced in Toner Production Example 1, evaluation was performed according to the following image evaluation method. Table 3 shows the obtained results. The developing sleeve used a DC bias component Vdc = -500 V, a superimposed AC bias component Vp-p = 1600 V, and f = 2000 Hz as a developing bias. The gap between the photoconductor and the developing sleeve is 300 μm.

<Embodiment 2> The toner 2 produced in the toner production example 2 was used, except that the developing sleeve 3 was used in the embodiment 1 and the peripheral speed of the photosensitive member was 55 mm / sec and the peripheral speed of the sleeve was 120% of the peripheral speed of the photosensitive member. Evaluation was performed in the same manner as in Example 1. Table 3 shows the obtained results.

<Example 3> In Example 1, the toner 3 produced in Toner Production Example 3 was used except that the peripheral speed of the photosensitive member was set to 200 mm / sec and the peripheral speed of the sleeve to the peripheral speed of the photosensitive member was set to 140%. Evaluation was performed similarly. Table 3 shows the obtained results.

<Example 4> Evaluation was performed in the same manner as in Example 1 except that the toner 4 prepared in Toner Production Example 4 was used. Table 3 shows the obtained results.

<Embodiment 5> An LBP is used as an image forming apparatus.
A 350 (manufactured by Canon) remodeling machine was used. Similarly, the EP22 process cartridge (manufactured by Canon) was modified as the process cartridge, and the photosensitive member 2 and the developing sleeve 2 were used. The peripheral speed of the photosensitive member was 55 mm / sec. As 120%,
The same evaluation was performed using Toner 5 produced in Toner Production Example 5. Table 3 shows the obtained results. Note that a DC bias component Vdc =
-430 V, superimposed AC bias component Vp-p = 15
00V, f = 1800 Hz was used. The gap between the photosensitive member and the developing sleeve is 280 μm.

<Embodiment 6> In Embodiment 5, the photosensitive member 3
The same evaluation was performed using the toner 6 produced in the toner production example 6 using the toner 6 and the developing sleeve 3. Table 3 shows the obtained results.

<Example 7> In Example 5, the same evaluation was performed using the toner 1 produced in Toner Production Example 1. Table 3 shows the obtained results.

<Comparative Example 1> Evaluation was performed in the same manner as in Example 1 except that the toner was changed to Toner 7 of Comparative Production Example 1. Table 3 shows the obtained results.

Comparative Example 2 Evaluation was performed in the same manner as in Example 2 except that the toner was changed to Toner 8 in Comparative Production Example 2. Table 3 shows the obtained results.

Comparative Example 3 Evaluation was performed in the same manner as in Example 3 except that the toner was changed to Toner 9 in Comparative Production Example 3. Table 3 shows the obtained results.

Table 2 shows a list of combinations of the toner, the developing sleeve, and the photosensitive member used in the above Examples and Comparative Examples.
It was shown to.

[0131]

[Table 2]

[0132]

[Table 3]

The evaluation results were determined as follows.

Image density After leaving the apparatus for 72 hours in a high-temperature and high-humidity environment (32.5 ° C., relative humidity 80%), 2,000 sheets were printed on A4 paper using a print pattern with a print ratio of 4%. . At this time, the solid black image densities of the 1, 10, 50, 100, 500 and 2000 sheets were measured. The image density was measured using a Macbeth reflection densitometer (manufactured by Macbeth). ：: very good (reflection density 1.3 or more) △: good (reflection density 1.2 to 1.3) ：: normal (reflection density 1.1 to 1.2) ×: bad (reflection density 1.3 to 1.3) Less than 1)

Dot Reproducibility The checker pattern shown in FIG. 8 was printed in a high-temperature and high-humidity environment (32.5 ° C., relative humidity 80%) under the above-described conditions, and the 1, 10, 50, 100, 500, and 2000th sheets Was evaluated based on the following evaluation criteria. ：: Very good (2 or less defects / 100) ○ △: Good (3 to 5/100 defects) △: Normal (6 to 10/100 defects) ×: Bad (10 or more defects / 100)

Ghost In a high temperature and high humidity environment (32.5 ° C., relative humidity 80%), 2,000 prints were made. At this time 1, 10,
The 50th, 100th, 500th, and 2000th negative ghosts were evaluated. To evaluate the image related to the ghost, a solid black band was output for one rotation of the sleeve, and then a halftone image was output. FIG. 7 shows a schematic diagram of the pattern. The evaluation method is the second round of the sleeve in one print image,
The difference between the reflection density measured by the Macbeth densitometer at the place where the black image was formed in the first cycle (black print area) and the place where the black image was not formed (non-image area) was calculated as follows. Negative ghost is a ghost phenomenon in which the density of the image that appears in the second round of the sleeve is generally lower than that of the non-image part in the first round, and the shape of the pattern that appears in the first round appears as it is. Evaluation was performed by using the difference in reflection density and the difference in reflection density. Reflection density difference = reflection density (where no image is formed)-reflection density
(Place where the image was formed)

Table 3 shows the average value. The smaller the difference between the reflection densities, the better the level and the better the ghost does not occur. The ghost was evaluated in five stages of ５, △, △, △ ×, and ×. Reflection density difference: 0.00 to 0.02 △: 0.02 to 0.04: 0.04 to 0.06 ×: 0.06 to 0.08 × : 0.08 or more

[0138]

As described above, by using the image forming method and the process cartridge using the toner having the circularity of the present invention, a good image can be obtained even in a high-temperature and high-humidity environment.

[Brief description of the drawings]

FIG. 1 shows an explanatory diagram of a methanol wettability transmittance curve.

FIG. 2 is a schematic sectional view of an example of a mechanical pulverizer used in a pulverizing step of a toner having a circularity in the present invention.

FIG. 3 is a schematic diagram on the D-D 'plane in FIG.

FIG. 4 is a perspective view of the rotor shown in FIG. 2;

FIG. 5 is a diagram schematically illustrating an example of an image forming apparatus used in the image forming method of the present invention.

FIG. 6 is an explanatory view showing an embodiment of the process cartridge of the present invention.

FIG. 7 is an explanatory diagram of a ghost.

FIG. 8 shows a pattern diagram of dot reproducibility evaluation.

FIG. 9 is a schematic view illustrating an example of a configuration of a photoconductor used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging roller 3 Exposure optical system 4 Developing device 5 Toner carrier 6 Toner layer thickness regulating member 7 Toner stirring means 8 Developing bias power supply 9 Transfer device 10 Transfer current generator 11 Cleaning blade 12 Fixing device 13 Toner P Transfer material (Recording material)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shunji Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazunori Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon F term in the company (reference) 2H005 AA08 CA26 CB13 EA05 EA10 2H035 CA07 CB01 CG01 2H077 AD06 AD13 AD36 EA12 EA18

Claims (18)

[Claims] 1. A magnetic toner contained in a developing container is regulated by a toner layer regulating member, and while forming a thin layer of the magnetic toner on the toner carrier, the toner image is carried by the toner carrier. The latent image formed on the latent image carrier is developed with the magnetic toner. The diameter of the toner carrier is D1 (mm), and the diameter of the latent image carrier is D2 (mm), peripheral speed V of the latent image carrier
(Mm / sec), D1 / D2 ≦ 0.5, D2
≦ 30, 55 ≦ V, wherein the magnetic toner is obtained by externally adding and mixing an organically treated inorganic fine powder to magnetic toner particles having at least a binder resin and a magnetic substance. The following formula (1) indicates a circularity a = L ₀ / L (1) (where L ₀ indicates the circumference of a circle having the same projected area as the particle image, and L indicates the circumference of the particle image) The toner for forming an image is characterized in that particles having a circularity a of 0.900 or more, which is determined by the following formula, have a cumulative value based on the number of 80% or more. 2. The image forming apparatus according to claim 1, wherein a constant gap is maintained between the latent image carrier and the toner carrier, and the toner carrier is developed by applying an AC voltage to the toner carrier. toner. 3. The toner carrier according to claim 1, wherein said toner carrier has a conductive coating layer, and said toner layer regulating member is elastically pressed against said toner carrier via a magnetic toner layer. 3. The image forming toner according to 1 or 2. 4. The toner carrier has a diameter of D1 (mm),
When the diameter of the latent image carrier is D2 (mm) and the peripheral speed of the latent image carrier is V (mm / sec), 0.2 ≦ D1 / D2 ≦
The image forming toner according to claim 1, wherein 0.5 and 55 ≦ V ≦ 200. 5. Particles having a circularity a of 0.900 or more in a number-based cumulative value of 90% or more, and particles having a circularity a of 0.950 or more in a number-based cumulative value of 67% or more. Particles having a circularity a of 0.995 or more as a cumulative value on a number basis of 8% or more, and a circularity a of 0.995 or more having a circularity a of 0.950 or more. The toner according to any one of claims 1 to 4, wherein the toner is present in a proportion occupying 12% or more of the cumulative value based on the number of particles. 6. The wettability of the magnetic magnetic toner particles to a mixed solvent of methanol / water of the magnetic toner particles is 780.
When measured by the transmittance of light having a wavelength of nm, the transmittance is 80%.
The methanol concentration in the range of 60 to 75%,
6. The method according to claim 1, wherein the lowest point of the transmittance of the curve with the methanol concentration on the X axis and the transmittance on the Y axis is within the range of 65 to 80% of the methanol concentration. The toner for image formation according to the above. 7. A method for regulating a magnetic toner contained in a developing container by a toner layer regulating member to form a thin layer of the magnetic toner on the toner carrier while carrying the latent image by the toner carrier. An image forming method of transporting the latent image formed on the latent image carrier with the magnetic toner to a developing unit facing the body, wherein the diameter of the toner carrier is D1 (mm); The diameter of the body is D2 (mm), and the peripheral speed V (mm /
Second), D1 / D2 ≦ 0.5, D2 ≦ 30,
55 ≦ V, wherein the magnetic toner is a magnetic toner obtained by externally adding and mixing an organically treated inorganic fine powder to magnetic toner particles having at least a binder resin and a magnetic substance, Circularity a = L ₀ / L (1) (where L ₀ represents the circumference of a circle having the same projected area as the particle image, and L represents the circumference of the particle image). Has a particle size of 0.900 or more in terms of the number-based cumulative value of 80% or more. 8. The image forming method according to claim 7, wherein a constant gap is maintained between the latent image carrier and the toner carrier, and an AC voltage is applied to the toner carrier for development. . 9. The toner carrier according to claim 1, wherein said toner carrier has a conductive coating layer, and said toner layer regulating member is elastically pressed against said toner carrier via a magnetic toner layer. 9. The image forming method according to 7 or 8. 10. The toner carrier having a diameter of D1 (m
m), when the diameter of the latent image carrier is D2 (mm) and the peripheral speed of the latent image carrier is V (mm / sec), 0.2 ≦ D1 /
The image forming method according to claim 7, wherein D2 ≦ 0.5 and 55 ≦ V ≦ 200. 11. Particles having a circularity a of 0.900 or more have a cumulative number-based value of 90% or more, and particles having a circularity a of 0.950 or more have a cumulative number-based value of 67% or more. Particles having a circularity a of 0.995 or more as a cumulative value on a number basis of 8% or more, and a circularity a of 0.995 or more having a circularity a of 0.950 or more. The image forming method according to any one of claims 7 to 10, wherein the particles are present in a proportion occupying 12% or more of the cumulative value based on the number of particles. 12. The wettability of the magnetic toner particles with respect to a mixed solvent of methanol / water of the magnetic toner particles is 78.
When measured at a transmittance of light having a wavelength of 0 nm, the transmittance is 80%.
%, The methanol concentration is in the range of 60 to 75%, and the lowest point of the transmittance of the curve with the methanol concentration on the X axis and the transmittance on the Y axis is the methanol concentration of 65 to 80%.
The image forming method according to any one of claims 7 to 11, wherein: 13. A latent image carrier for carrying a latent image,
What is claimed is: 1. A process cartridge having at least an integral developing container having at least a toner carrier and a toner layer regulating member, wherein a magnetic toner accommodated in the developing container is regulated by the toner layer regulating member, and a magnetic layer is formed on the toner carrier. While forming a thin layer of toner, the magnetic toner is transported by the toner carrier to a developing section facing the latent image carrier, and the latent image formed on the latent image carrier is developed with the magnetic toner. A process cartridge detachably mountable to an image forming apparatus main body for performing an image forming method, wherein the toner cartridge has a diameter of D1 (mm) when mounted on the image forming apparatus main body and forms an image; Diameter is D2 (m
m), when the peripheral speed of the latent image carrier is V (mm / sec), D1 / D2 ≦ 0.5, D2 ≦ 30, 55 ≦ V is satisfied; And magnetic toner particles having a magnetic substance, and an inorganic fine powder that has been subjected to an organic treatment is externally added to and mixed with the toner. The following formula (1): circularity a = L ₀ / L (1) ₀ indicates the perimeter of a circle having the same projection area as the particle image, and L indicates the perimeter of the particle image. A process cartridge having the above. 14. The process cartridge according to claim 13, wherein a constant gap is maintained between the latent image carrier and the toner carrier, and an AC voltage is applied to the toner carrier for development. 15. The toner carrier having a conductive coating layer, wherein the toner layer regulating member is elastically pressed against the toner carrier via a magnetic toner layer. 15. The process cartridge according to 13 or 14. 16. The toner carrier having a diameter of D1 (m
m), when the diameter of the latent image carrier is D2 (mm) and the peripheral speed of the latent image carrier is V (mm / sec), 0.2 ≦ D1 /
The process cartridge according to claim 13, wherein D2 ≦ 0.5 and 55 ≦ V ≦ 200. 17. Particles having a circularity a of 0.900 or more have a cumulative number-based value of 90% or more, and particles having a circularity a of 0.950 or more have a cumulative number-based value of 67% or more. Particles having a circularity a of 0.995 or more as a cumulative value on a number basis of 8% or more, and a circularity a of 0.995 or more having a circularity a of 0.950 or more. 17. The process cartridge according to claim 13, wherein the particles are present in a proportion occupying 12% or more of the cumulative value based on the number of particles. 18. The wettability of the magnetic toner particles with respect to a mixed solvent of methanol / water of the magnetic toner particles is 78.
When measured at a transmittance of light having a wavelength of 0 nm, the transmittance is 80%.
%, The methanol concentration is in the range of 60 to 75%, and the lowest point of the transmittance of the curve with the methanol concentration on the X axis and the transmittance on the Y axis is the methanol concentration of 65 to 80%.
The process cartridge according to any one of claims 13 to 17, wherein