JP2001042625A - Method for image forming and developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming an image superior in replenishment property of the developer, by which the total number of copyied sheets at one replenishment of the developer is increased and a highly precise image is outputted, even before and after replenishment of the developer. SOLUTION: By this method for forming images, image formation is performed by adopting a developing device provided with developer carrier, a first containing chamber (sectional area S1) containing the developer, and transporting the developer on the developer carrier, a second containing chamber (sectional area S2) containing the developer and transporting the developer to the first contacting chamber, in which S1 is 6 to 18 cm2 and the ratio of S2 to S1 (S2/S1) is 4.2 to 8.2, and the developer incorporating at least a binding resin, magnetic bodies and the charge controlling agent, and moreover incorporating a toner provided with 5 to 35 deg. for the angle of repose under an environment where the temp is 23 deg.C and the relative humidity is 60%, with 3 to 35% flow index (flocculation degree).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method used in electrophotography, electrostatic recording, and the like.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been 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. And then developing the latent image with toner, transferring a toner image to a transfer material such as paper as necessary, and fixing by heating, pressure, heating and pressurizing, or solvent vapor to obtain a copy. What you get. Then, the toner (developer) remaining on the photoconductor without being transferred is cleaned by various methods, and the above-described steps are repeated.

In recent years, such copying apparatuses have begun to be used not only as office work copying machines for simply copying original documents, but also in the field of personal copies for individuals. For this reason, smaller, more personal, more ecological, and more reliable devices have been strictly pursued, and copiers have come to be composed of elements having a high degree of customer satisfaction in various respects. As a result, in the development of a copying apparatus, a more user-friendly mechanical design is required, and in that, the toner design must be performed from the user's point of view. If the performance of the toner cannot be improved, it will be better. The equipment is no longer feasible. For example, in a copying machine for personal use, there is a demand for ease of toner replenishment, an increase in the number of copies per replenishment, and the like.

Hitherto, the improvement of toner replenishment has been mainly performed by improving a toner container containing toner to be replenished. That is, the toner replenishing property has been improved by improving the mountability between the toner container and the developing machine or the toner hopper, the sealing property after the mounting, the detachability after the replenishment, and the like. On the other hand, the improvement of the toner is mainly performed to improve the developing property and the fixing property. At present, the improvement of the toner replenishment is less than that of the toner container.

Further, in order to reduce the size of the copying apparatus, there is a need for a developer that can contribute to simplifying and reducing the size of the apparatus involved in each process step. For example, when a two-component developer is used in the development process, it is difficult to reduce the size of the machine in view of the necessity of an ATR mechanism for controlling the mixing ratio of the toner and the carrier. On the contrary,
The use of a one-component developer is advantageous in miniaturizing the apparatus. Further, in the case of a magnetic one-component type developer, the toner specific gravity is larger than that of the non-magnetic toner, so that toner scattering at the time of replenishment of the developer is slight and a member for preventing toner scattering can be simplified, so that personal Preferred for youth copiers.

Various methods have been studied as a developing method using a magnetic one-component developer. For example, JP
JP-A-5-18656 proposes a jumping development method. This involves applying a very thin magnetic toner on a sleeve, triboelectrically charging it, and then developing it in close proximity to the electrostatic image. This method increases the chances of contact between the sleeve and the toner by applying the magnetic toner on the sleeve very thinly, enables sufficient frictional charging, supports the magnetic toner by magnetic force, and fixes the magnet and the toner with each other. Are relatively moved, thereby dissolving the toner particles from each other and dissolving the toner sufficiently with the sleeve to obtain an excellent image.

In order to further reduce the size of the copying machine using this developing method, a toner container such as a cartridge is used without using a member for increasing the size of the copying machine, such as a hopper for supplying toner. In recent years, a system for directly supplying toner to a developing device has been widely used.

[0008] In such a developing device, a first accommodating chamber (developing chamber) accommodating the developer and the developer carrying member communicates with the first accommodating chamber and is consumed in the first accommodating chamber. It comprises a second storage chamber (developer supply chamber) for storing a developer for replenishing the developer.

This type of toner replenishment system has the above-mentioned advantages in terms of space, and a large amount of toner is replenished at one time in the developing device. Since the number of copies per replenishment depends on the amount of toner to be replenished, if the space of the developer supply chamber for storing the developer is increased,
The number of copies per refill increases, and the number of refills by the user decreases. As a result, a user-friendly copying machine can be provided.

However, as the size of the developer supply chamber is increased, the circulation of toner in the developer supply chamber becomes more difficult. In order to smoothly transport and supply the developer to the developer chamber, appropriate stirring means must be provided in the developer chamber. The developing device is required to be provided in the developer supply chamber. The toner circulation in the developing device is controlled by the shape of the stirring member, the stirring motion, the shape of the developing device, and the like. From this viewpoint, many studies have been made in terms of process and mechanism, and the results have been successful. As a result, the cost of the developing apparatus and the cost of the copying machine itself associated with stirring have risen, and the personal copying machine tends to be expensive. There is. Attempts to avoid this with toner have rarely been made.

On the other hand, in the above-described collective replenishment type developing device, the toner remaining in the developing device at the time of replenishment is a toner that has undergone frictional charging to some extent and has maintained the charge amount.
The amount is decreasing. On the other hand, the replenished toner has a lower charge amount and a larger charge amount than the residual toner, and therefore, variations in both charge amounts cause problems such as a decrease in image density before and after toner replenishment and generation of fog.

Further, as the process speed becomes higher, it becomes more difficult to achieve both the toner transportability and the packing performance in the developing device, and it becomes more difficult to always maintain stable development performance. In other words, in a system with a configuration that emphasizes transportability, the amount of toner transported from the developer supply chamber exceeds the amount of toner to be replenished to the development chamber because it is consumed in development, and the developer carrier and the blade Is compressed in the vicinity of, forming a packing state. As a result, the toner circulation in the developing chamber and the toner coating on the developer carrying member become insufficient, so that the developability is reduced. On the other hand, if the system is configured with emphasis on packing properties, when a large number of originals with a high image ratio are copied, the toner transport cannot catch up, the amount of toner supplied to the developing chamber decreases, and problems such as white spots occur. Occurs. In particular, the present inventors have found that these problems tend to become more pronounced when the space in the developer supply chamber is increased.

Various studies have been made to improve toner circulation, toner transportability, and packing in the developing unit in such a collective replenishment system, but these methods are still insufficient, and images containing toner are still insufficient. The forming method has many points to be improved.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned point, and significantly improves the problems of the prior art as described above. It is an object to provide an image forming method capable of outputting an image.

Another object of the present invention is to provide an image forming method capable of increasing the total number of copies per toner supply. Another object of the present invention is to provide an image forming method which exhibits high performance in toner replenishment.

A further object of the present invention is to provide an image forming method which does not cause a reduction in image density or fog even before and after toner replenishment.

[0017]

The present inventor has made the following inventions in the course of intensive studies to solve the above-mentioned various problems and to develop an image forming apparatus meeting the object of the present invention.

That is, according to the image forming method of the present invention, the electrostatic latent image carried on the latent image carrier is visualized by the toner contained in the developer filled in the developing device, thereby forming the toner image. An image forming method for forming on the latent image carrier, transferring the toner image to a transfer material, and fixing the toner image transferred to the transfer material to the transfer material, wherein the developing device comprises: (a) A) a first for containing said developer;
An accommodating chamber, and (b) accommodating the developer, and
A second storage chamber communicated with the storage chamber, and (c) a cylindrical shape which is disposed to face the latent image support and has a side surface facing a support surface for supporting the developer, and a central axis of the cylinder. A developer carrier for transporting the developer to a developing area that is the closest part between the carrier surface and the image carrier by rotating about the rotation axis, (d) in the first storage chamber. A first stirring and conveying means for stirring the developer accommodated in the first accommodation chamber along the direction of the rotation axis of the developer carrier and conveying the developer to the developer carrier; And (e) second stirring / transporting means disposed in the second storage chamber for stirring the developer stored in the second storage chamber and transporting the developer to the first storage chamber. When the sectional area of the first storage chamber is S1 and the sectional area of the second storage chamber is S2 in a vertical section near the center of the central axis of the developer carrying member of the developing device, S1 is 6 ~
18 cm ² and the ratio of S2 to S1 (S2
/ S1) is 4.2 to 8.2, and the toner contained in the developer contains at least a binder resin, a magnetic substance, and a charge control agent. Humidity 6
The angle of repose in an environment of 0% is 5 to 35 °, and
The fluidity index (cohesion degree) in the above environment is 3 to 35%.

That is, according to the image forming method of the present invention, in the developing method using the developing device having the first storage chamber and the second storage chamber, the angle of repose and the degree of agglomeration of the toner contained in the developer are determined. By setting the value to, it is possible to provide a developing method having excellent developer replenishment.

In the above image forming method, the peripheral speed of the developer carrying member is preferably 80 mm / s or more.

The weight average diameter of the toner used in the image forming method is preferably 3.5 to 12.0 μm. Further, the binder resin of the toner preferably contains at least a polyester resin.

The developer of the present invention is a developer for visualizing an electrostatic latent image carried on a latent image carrier, and comprises a binder resin, a magnetic material, and a charge control agent. Containing at least a toner having a temperature of 23.
The angle of repose is 5 to 35 in an environment where the temperature is 60 ° C and the relative humidity is 60%.
° and a fluidity index (cohesion degree) in the above environment of 3 to 35%.

Further, the developing device of the present invention is a developing device for visualizing an electrostatic latent image carried on a latent image carrier, and (A) a device for containing the developer of the present invention. A first accommodating chamber, (B) a second accommodating chamber accommodating the developer and communicating with the first accommodating chamber, and (C) an opposing latent image carrier, and Has a cylindrical surface having a side surface on which the developer is carried, and is rotated about a central axis of the cylinder as a rotation axis, so that the developing region is formed in a developing region which is a closest portion between the supporting surface and the image carrier. A developer carrier for transporting the developer; and (D) agitating the developer housed in the first chamber and accommodated in the first chamber along the rotation axis direction of the developer carrier. (A) first stirring and conveying means for conveying the developer to the developer carrier; It is disposed in the second accommodating chamber, the second
A second stirring and conveying means for stirring the developer stored in the storage chamber and transferring the developer to the first storage chamber. And
In a vertical section near the center of the central axis of the developer carrying member, when the sectional area of the first storage chamber is S1 and the sectional area of the second storage chamber is S2, S1 is 6 to 18 cm ^2.
And the ratio of S2 to S1 (S2 / S1) is 4.2 to 8.2.

[0024]

Embodiments of the present invention will be described below.

In the image forming method of the present invention, the toner image is formed on the latent image carrier by visualizing the electrostatic latent image carried on the latent image carrier by toner filled in the developing device. The present invention relates to an image forming method for forming, transferring the toner image to a transfer material, and fixing the toner image transferred to the transfer material to the transfer material. The developing device used in the present invention includes: (a) a first storage chamber for storing a developer;
(B) a second storage chamber that stores the developer and is communicated with the first storage chamber; and (c) is disposed to face the latent image carrier,
It has a cylindrical shape with the supporting surface for supporting the developer as a side surface,
By rotating around the center axis of this cylinder as a rotation axis,
A developer carrier for transporting the developer to a developing area which is the closest part between the carrier surface and the image carrier; and (d) a developer arranged in the first chamber and housed in the first chamber. A first agitating / conveying means for agitating the developer along the direction of the rotation axis of the developer carrying member and carrying the developer to the developer carrying member; A second stirring and conveying means for stirring the developer stored in the storage chamber and transferring the developer to the first storage chamber; In the vertical section near the center of the central axis of the toner carrier of the developing device, the first
The sectional area of the accommodation room is S1, and the sectional area of the second accommodation room is S2.
, S1 is 6 to 18 cm ² and S
The ratio of S2 to 1 (S2 / S1) is 4.2 to 8.2. The toner contains at least a binder resin, a magnetic substance, and a charge control agent, has a repose angle of 5 to 35 ° in an environment with a temperature of 23 ° C and a relative humidity of 60%, and The fluidity index (cohesion degree) in the above environment is 3 to 35%.

The present inventor considers the reason why the above-described image forming method of the present invention exerts its original effect as follows.

In a configuration of a collective replenishment developing device for directly replenishing a developer from a developer container such as a cartridge to the developing device without using a member for increasing the size of the copying machine such as a hopper for replenishing the developer. By defining S1 and S2 / S1, the space for the hopper device and related members other than the developing container can be reduced, so that the size of the device can be reduced.

Further, in the configuration of the collective supply developing device,
By defining S1 and S2 / S1, and the fluidity index (Ψ), the developer in the developing device (the developing chamber (corresponding to the first storage chamber) and the developer supply chamber (corresponding to the second storage chamber)) Of the developer, the transportability of the developer from the developer supply chamber to the developer chamber and the packing property of the developer in the developer chamber can be improved, and a high-definition image can be output for a long period of time.

Further, by defining S1 and S2 / S1, it becomes possible to increase the total amount of the developer that can be supplied to the developing device as compared with the related art, thereby reducing the number of replenishments for the same number of copies, and The time and labor spent on supplying the developer can be reduced.

Further, in the construction of the collective replenishment developing device, S1 and S2 / S1 and the angle of repose (Φ) of the toner contained in the developer are defined. Thereby, the capacity of the developer supply chamber (that is, the sectional area (S
Even if 2)) is large, the angle of repose (Φ) is relatively small, so that only the operation of replenishing a large amount of developer from the developer container into the developer supply chamber is likely to make the surface of the developer layer smooth. . As a result, the developer can flow into the developer supply chamber without excess or shortage, and the work of shaking the developing device to smooth the surface of the developer layer is reduced or eliminated, and the developer replenishing property for the customer is reduced. Will be improved.

In the structure of the collective replenishment developing device, S1,
S2 / S1, toner fluidity index (Ψ), and angle of repose
By defining (Φ), it was possible to suppress a decrease in image density and generation of fogging before and after the replenishment of the developer. That is, in the configuration of the collective replenishment developing device, S1, S2
/ S1, when the fluidity index (Ψ) is defined, when the stirring means is constant, the circulating property of the developer in the developing device can be controlled. For this reason, the replenished developer is likely to be mixed with the developer in the developer supply chamber or the developer chamber immediately before replenishment, thereby suppressing non-uniform charging between toner particles. Also, if Φ and Ψ of the toner are the desired values, the flow of the toner particles conveyed from the developer supply chamber to the developing chamber, and the toner particles staying before the development in the developing chamber and the developer carrier charge the toner particles. The flow of toner particles, such as the flow of toner particles, can be suppressed. As a result, before and after replenishment, there is little change in the charging ability of the toner particles, and there is no shortage of toner conveyance, so that a decrease in image density and generation of fog can be suppressed.

Hereinafter, the present invention will be described in more detail. The developing step used in the image forming method of the present invention includes:
A magnetic one-component developing method or a magnetic two-component developing method can be used. The former is preferable in view of downsizing and cost reduction of the machine, so the case where the magnetic one-component developing method is used will be described.

<Image Forming Method> First, the developing device will be described. FIG. 1 is a diagram showing a preferred example of a developing device that can be used in the image forming method of the present invention.

FIG. 1 is a sectional view of the developing device 111,
The inside of the developing device 111 is divided into a developing chamber 112 as a first storage chamber and a developer supply chamber 113 as a second storage chamber, and the development chamber 112 and the developer supply chamber 113 can communicate with each other. Are partitioned by a partition member 114. The developing chamber 112 and the developer supply chamber 113 accommodate a developer 120 which is a one-component developer.

In the developing chamber 112 of the developing device 111, a developer carrier (developing sleeve) which carries the developer 120 and conveys it toward the photosensitive drum 110 as a latent image carrier.
115 are accommodated. Here, the photosensitive drum 110
Is preferably 20 to 40 mm in diameter, and the developing sleeve 115 is 10 to 40 m in diameter.
It is better to use the one that is m.

In the present invention, as the developer carrying member 115, a material such as metal and ceramics is used, but aluminum, SUS and the like are preferable from the viewpoint of charging property to the developer. The developer carrier can be used as it is drawn or cut, but in order to control the transportability of the developer and the triboelectrification, it can be polished, roughened in the circumferential or longitudinal direction, or blasted. It is preferable to perform coating or coating. In particular, the developer carrier is preferably a developing sleeve having a resin layer in which conductive fine powder is dispersed on a metal substrate.

The developing sleeve 115 is disposed in the developing chamber 112 such that a part of the outer peripheral surface thereof projects outside, and is supported by the developing sleeve 115 between the developing sleeve 115 and the photosensitive drum 110. Photosensitive drum 1
A developing area, which is the closest part between the photosensitive drum 110 and the developing sleeve 115 and is indicated by A in FIG. In the developing sleeve 115, a magnet 116 as a magnetic field generating means is fixed. Magnet 1
Reference numeral 16 includes a developing pole S ₁ , a transport pole S ₂ for transporting the developer, a cut pole N _1, and a take-in pole N ₂ .

Above the developing sleeve 115, a doctor blade 117 for regulating the layer thickness of the developer carried on the developing sleeve 115 is arranged.

Here, in the present invention, as the doctor blade 117, a metal blade, a magnetic blade or a resilient blade which is brought into contact with the surface of the developing sleeve 115 by an elastic force is disposed at a certain distance from the developing sleeve 115. Can be used. When a metal blade or a magnetic blade is used, the gap with the developing sleeve 115 is preferably 50 to 500 μm, and more preferably 100 to 400 μm.

As the elastic blade, silicone rubber,
Rubber elastic materials such as urethane rubber and NBR; synthetic resin elastic materials such as polyethylene and terephthalate; metal elastic materials such as stainless steel and steel can be used. Also, a composite of these materials can be used. Preferably, it is a rubber elastic body.

Further, the material of the elastic blade greatly affects the chargeability of the developer on the developing sleeve 115. Therefore, an organic substance or an inorganic substance may be added to the elastic body. Such an additive may be melt-mixed or dispersed in the elastic body. Examples of such additives include metal oxides, metal powders, ceramics, carbon allotropes, whiskers, inorganic fibers, dyes, pigments, surfactants, and the like. Further, for the purpose of controlling the charging of the developer, a developing sleeve is further brought into contact with the rubber elastic body, synthetic resin elastic body, or metal elastic body by using a substance such as resin, rubber, metal oxide, or metal. The one attached so as to hit the portion may be used. When durability is required for each of the elastic body and the developing sleeve, it is preferable that a resin or rubber is bonded so as to contact the developing sleeve contact portion of the metal elastic body. As the material of resin and rubber,
Urethane rubber, urethane resin, silicone rubber, silicone resin, polyester resin, fluororesin (for example, Teflon (registered trademark) resin), polyimide resin, and those easily charged to negative polarity are preferable. In particular, silicone rubber can be preferably used. When the developing sleeve contact portion is a molded body such as a resin or rubber, metal oxides such as silica, alumina, titania, tin oxide, zirconia, and zinc oxide are included therein to adjust the chargeability of the developer. , Carbon black, and a charge control agent generally used for a developer.

When an elastic blade is used, the base on the upper side is fixed / held to the developing device side, and the lower side is bent in the forward or reverse direction of the developing sleeve 115 against the elasticity of the blade. With the blade bent, the inner surface of the blade (the outer surface in the case of the opposite direction) is brought into contact with the sleeve surface with an appropriate elastic pressure.

It is preferable that the thickness of the developer layer on the developing sleeve 115 is smaller than the gap between the developing sleeve 115 and the latent image carrier 110. The thickness of the developer layer may be regulated so that a part of the ears is in contact with the latent image carrier.

On the other hand, in the developing chamber 112 of the developing device 111, a rotatable first stirring / conveying means 118 is installed so that its rotation axis is substantially parallel to the rotation axis of the developing sleeve 115. Further, a rotatable second stirring / conveying means 119 is provided in the developer supply chamber 113 and a first stirring / conveying means 118 is provided.
And are installed in parallel or almost parallel. That is, the second stirring and conveying means 118 has a rotation axis of the first
It is installed so as to be substantially parallel to the rotation axis of the stirring and conveying means. As these first and second stirring and conveying means, known means such as a screw can be used. Note that the developing sleeve 115, the first stirring and conveying means 11
8 and the second stirring and conveying means 119 are rotating in the same direction, and the driving of rotation is all synchronized.

With such a configuration, the first stirring / conveying means 118 stirs the developer 120 accommodated in the developing chamber 112 along the rotation axis direction of the developer carrying member 115, and transfers the developer 120 to the developer. The developer can be transported to the carrier 115, and the second stirring and transporting means 119 can agitate and transport the developer 120 contained in the developer supply chamber 113 to the developing chamber 112.

When the developing device 111 is used, the developer supply chamber 1
At 13, the supplied developer and the developer in the developing device are transported to the developing chamber 112 little by little from the gap between the partition member 114 and the developer supply chamber 113 while being agitated by the second agitating and transporting means 119. Is done. In the developing chamber 112, the transported developer is sent in the axial direction of the developing sleeve 115 by the first stirring and transporting means 118, and the developer 120 is transported by the S ₂ pole of the developing sleeve 115 during the transport.
It is carried on a carrying surface which is the surface of the developing sleeve 115.
The developer 120 carried on the developing sleeve 115 is
After being regulated to a predetermined layer thickness by the doctor blade 117, it is sent to the developing area A. In the developing area A, the developer is transferred to a portion of the photosensitive drum 110 where a latent electrostatic image is formed.

The developer that has passed through the developing region A falls from the developing sleeve 115 to the developing chamber 112 near the point where the magnetic force between the N ₂ pole and the S ₂ pole on the developing sleeve 115 becomes zero. The developer dropped from the developing sleeve 115 is taken into the first stirring and conveying device 118. This developer is returned to the developer supply chamber 113 again by the first stirring and conveying means 118. Then, being stirred and mixed with the developer remaining in the developing device by the first stirring and conveying means 118, a developer having a sufficient triboelectric charge in the magnetic pole S ₂ is developing sleeve 11
5 is supplied. Further, the developer is removed from the developing sleeve 115 near the position where the magnetic force between the magnetic poles N ₂ and S ₂ becomes zero, so that the recovery of the developer from the developing sleeve 115 in the developing chamber 112 is ensured. It can be carried out.

In the developing chamber 112, the developer 120 is agitated and transported by the rotation of the first agitating and transporting means 118, so that the developer can be transported smoothly and uniformly in the axial direction of the developing sleeve. Therefore, when continuously forming images with a large consumption of the developer, there is no difference between the image density on the upstream side and the image density on the downstream side. Further, in order to increase the transport speed while maintaining high stirring efficiency, it is not necessary to increase the outer diameter of the first stirring and transporting means 118 or to increase the rotation speed, thereby preventing an increase in the size of the apparatus. Will be possible.

Note that a developer remaining amount detecting means 121 is provided to detect the remaining amount of the developer 120 contained in the developing device 111. This developer remaining amount detecting means 1
As 21, a piezoelectric sensor, a piezo element, an antenna residual detection, or the like can be used.

FIG. 2 shows a developing sleeve 1 of the developing device shown in FIG.
In the vertical section near the center of the axis of No. 15, the sectional area of the developing chamber 112 as the first developer accommodating chamber is S1, and the sectional area of the developer supply chamber 113 as the second developer accommodating chamber is S2.
FIG. 9 is a schematic explanatory diagram for obtaining S1 and S2 / S1 when “1” is set. When obtaining S1 and S2, first,
From the three-dimensional measurement of the developing chamber 112 and the developer supply chamber 113, a vertical sectional view near the axial center of the developing container is created. If necessary, the developing chamber 112 and the developer supply chamber 113 may be vertically cut with a cutting tool, and the cut may be measured three-dimensionally to create a vertical sectional view.
In the sectional view, after calculating S1 and S2, S2
/ S1.

In the present invention, S1 is 6 to 18 cm ²
It is characterized by being. If the value of S1 is smaller than the above range, when images having a large print ratio are continuously output, white spots occur because the total amount of developer in the developing chamber is small.
Etc. may occur. On the other hand, if S1 is too large, the developer circulation in the developing chamber 112 may be insufficient, and a high-definition image may not be obtained. S1 is preferably 6 to 15 cm ² , and 8
More preferably, it is about 15 cm ² .

The present invention is characterized in that S2 / S1 is 4.2 to 8.2. If S2 / S1 is smaller than the above range, the total number of copies per replenishment decreases, and the effect of the present invention may not be obtained. On the other hand, if S2 / S1 is larger than the above range, the developer circulation in the developer supply chamber occurs, and the developer transportability is reduced, which is not preferable.

FIGS. 3A and 3B are schematic sectional views showing the state of the developing device before and after the supply of the developer. FIG. 3A shows the state before the supply of the developer, and FIG. ing. The developer 120 in the developing device 111 is
Is consumed, and when it becomes necessary to supply it, the developing device 111 is once taken out of the main body of the image forming apparatus (described later), and the supply port 122 is opened above the developer supply chamber 113 of the developing device 111. Then, the developer 120 which is a one-component developer contained in the developer cartridge 123 which is a developer container is supplied. At this time, if the angle of repose (Φ) of the toner contained in the developer 120 is small, FIG.
In (b), the surface of the developer layer formed by the developer replenished in the developer supply chamber 113 is easily smoothed, and the replenishment (non-shake properties) of the developer is improved. After the developer is supplied, the developer cartridge 123 is moved to the developing device 111.
It is sufficient to remove the developing device 111 and attach the developing device 111 to a predetermined position of the image forming apparatus main body.

In this way, the replenished developer 120
And the developer 120 returned from the developing chamber 112 to the developer supply chamber 113 are sufficiently agitated by the second agitating / conveying means 119, so that a sufficient amount of tribo can be given to the replenishment developer. Ground fog, reversal fog and a decrease in density due to shortage can be prevented.

Further, the developer 120 is again sent from the developer supply chamber 113 to the development chamber 112 by the second stirring / conveying means 119, and passes through the development chamber 112 to the developer supply chamber 1.
The circulation of the developer, which is returned to 13, is performed.

FIG. 4 is a schematic sectional view showing an example of an image forming apparatus to which the image forming method and the developing device of the present invention are applied. In FIG. 4, the image forming apparatus includes a photosensitive drum 1
10, primary charger 131, exposure system 132, developing device 11
1, a transfer device 140, a heat and pressure fixing device 136, a cleaner 138, and an erase exposure device 139. In this figure, the transfer device 140 has a transfer charger 134 and a transport belt 135.

Hereinafter, a preferred specific example of the image forming method of the present invention will be described with reference to FIG. When an OPC photosensitive drum is used as the photosensitive drum 110 serving as a latent image carrier, first, the surface of the photosensitive drum 110 is negatively charged using a primary charger 131. Next, image exposure is performed on the photosensitive drum 110 by the exposure system 132 to form an electrostatic latent image. A developing device 1 having a developing sleeve 115 containing a magnet 116 and a doctor blade 117 for regulating the layer thickness of the developing sleeve 115
Regular development is performed by using the developer 120 in FIG. At this time, a positively chargeable one-component magnetic toner is used as the developer 120.

The photosensitive drum 110 serving as a latent image carrier
When an amorphous silicon drum is used, the surface of the photosensitive drum 110 is positively charged to form a latent image,
Reversal development is performed using a positively chargeable one-component magnetic toner (hereinafter, sometimes referred to as “one-component magnetic toner”) 120.

Here, an AC bias, a pulse bias, and / or a DC bias are applied to the developing sleeve 115 by the bias applying means 133. Transfer paper P
Is transferred to the transfer device 140, the transfer charger 13
The toner image on the surface of the photosensitive drum is electrostatically transferred onto the transfer paper by being charged from the back side of the transfer paper (opposite side of the photosensitive drum 110) by 4. The transfer paper P separated from the photosensitive drum 110 is transported by the transport belt 135, and the toner image on the transfer paper P is fixed by the heating and pressing fixing device 136.

The one-component magnetic toner remaining on the photosensitive drum 110 after the transfer process is removed by a cleaner 138 having a cleaning blade 137. After the cleaning, the photosensitive drum 110 is neutralized by the erase exposure 139, and the process starting from the charging process by the primary charger 131 is repeated again.

As described above, an AC bias or a pulse bias may be applied to the developing sleeve 115 of the developing device 111 by the bias applying unit 133. This AC bias has a frequency of 200-4000H.
It is preferable that z and the amplitude Vpp be 500 to 3000 V.

When the one-component magnetic toner is transferred from the developing sleeve 115 to the photosensitive drum 110 at the developing site,
The toner is transferred to the electrostatic image side by an electrostatic force and a bias or a pulse bias on the surface of the photosensitive drum 110 holding the electrostatic latent image.

The developing sleeve 11 which is a developer carrying member
5 is rotated at a peripheral speed of 100 to 200% with respect to the photosensitive drum 110. In the present invention, the peripheral speed of the developer carrying member is preferably 80 mm / s or more. If the peripheral speed of the developer carrier is lower than the above range, the developer on the developer carrier may not be sufficiently charged in the developing chamber 112, and a high-definition image may not be obtained.

The charging and transferring steps which can be used in the present invention include: (1) a method of non-contact with a latent image carrier such as a method using a corona discharger; and (2) a roller type, belt type, belt and electrode blade. Any type of contact type, such as a combination of the above, can be used, and any type can be used.

The latent image bearing member of the present invention includes an amorphous silicon photosensitive member and an organic photosensitive member. The organic photoreceptor may be a so-called single-layer type in which the photosensitive layer contains a charge generating substance and a substance having charge transport performance in the same layer. It may be. A charge generation layer on a conductive substrate,
Next, a laminated photoreceptor having a structure in which the charge transport layers are laminated in this order is one of preferred examples.

When the organic compound forms the surface layer of the photoreceptor, the wax contained in the one-component magnetic toner exerts releasability at the contact point on the surface of the photoreceptor. And the occurrence of fusion and filming is suppressed.

Further, in the present invention, it is necessary to include a step of cleaning the one-component magnetic toner remaining on the surface of the latent image carrier after the transfer step, and transporting the cleaned waste toner to a waste toner container with a screw. . By combining this cleaning step with the developing method and the developer of the present invention, handleability of waste toner is improved,
The user can perform waste toner processing. For this reason, a serviceman cost for waste toner processing can be saved, a total running cost can be reduced, and customer satisfaction is improved.

As the cleaning method, blade cleaning, mag brush cleaning, fur brush cleaning, roller cleaning, and combinations thereof can be used. Among the above-described cleaning methods, blade cleaning is preferable.

In blade cleaning, urethane rubber, silicone rubber, or elastic resin is used as a blade, or a blade made of metal or the like holding a tip-shaped resin is used in a forward direction with respect to the moving direction of the photoreceptor. It is known as abutting or pressing in the opposite direction. Preferably, the blade is pressed against the photosensitive member in a direction opposite to the moving direction. At this time, the contact pressure of the blade against the photoreceptor is preferably 20 g / cm or more as a linear pressure, more preferably 30 to 80 g / cm.

In the fixing step of the present invention, a pressure fixing device, a heat-pressure fixing device, or the like can be used. Alternatively, a fixing unit that heats and fixes the one-component magnetic toner by a fixedly supported heating element and a pressing member that is in pressure contact with the heating element and that makes the transfer material adhere to the heating element via a film. Can be used.

<Developer> As described in the above-described image forming method, the developer in the present invention may be a magnetic one-component developer composed of only a toner described below (which does not require a carrier), or a toner and a carrier. A magnetic two-component developer is suitably used. In particular, a magnetic one-component developer is preferable.

The developer of the present invention contains at least a toner containing a binder resin, a magnetic substance, and a charge control agent. The toner has an angle of repose in an environment of 23 ° C. and 60% relative humidity. Φ) is 5 to 35 °, and the fluidity index (cohesion degree) に お け る in the environment is 3 to 35%. The angle of repose (Φ) in the above environment is
The angle is preferably 10 to 35 °, more preferably 20 to 35 °. Further, the fluidity index Ψ is preferably from 6 to 35%, more preferably from 10 to 35%.

If the angle of repose Φ is smaller than the above range,
Packing of the developer may occur in the developing chamber 112, and development streaks may occur. If the angle of repose Φ is larger than the above range, the developer supply chamber 11 is
Even if vibration is applied to 3, the surface of the developer layer may not be smooth, and a desired amount of developer may not be replenished.

If the fluidity index (aggregation degree) 小 さ is smaller than the above range, not only the transportability of the developer is lowered but also the chargeability of the developer during stirring becomes insufficient. If the fluidity index is larger than the above range, poor circulation of the developer may occur.

Although the details will be described later, the electrostatic interaction between the toner particles and the specific gravity of the toner itself can be controlled by specifying the particle size of the toner and the toner constituent material. The index Ψ is obtained.

FIG. 5 is a schematic diagram for explaining an example of a method of measuring the angle of repose. The repose angle Φ of the toner in the present invention can be obtained, for example, by the following method.

Measuring device: Powder tester PT-N type (Hosokawa Micron Corporation) Measuring method: It conforms to the measuring method of the angle of repose in the instruction manual attached to the powder tester PT-N type (opening of sieve 710 μm, vibration time 180 s, amplitude 2 mm or less). The toner is dropped from the funnel 2 onto the disk 3, and the angle between the generatrix of the toner accumulated on the disk 3 and the surface of the disk 3 is determined as the angle of repose.

However, after the sample was left overnight at 23 ° C. and a relative humidity of 60% (hereinafter referred to as “60% RH”), the sample was rested with a measuring device in an environment of 23 ° C. and 60% RH. The angle is measured, and the value obtained by repeating the measurement five times and taking the arithmetic average is defined as Φ.

FIG. 6 is a schematic explanatory diagram for explaining an example of a method of measuring the fluidity index (cohesion degree) Ψ. In FIG. 6, a sieve 4 having a mesh size of 250 μm, a sieve 5 having a mesh size of 150 μm, and a sieve 6 having a mesh size of 75 μm are stacked in this order from the top. The fluidity index (degree of aggregation) Ψ of the toner in the present invention can be determined, for example, by the following method.

Measuring device: Powder tester PT-N type (Hosokawa Micron Corporation) Measuring method: It conforms to the measuring method of agglomeration degree in the instruction manual attached to the powder tester PT-N type.

Node opening 250 μm, 150 μm, 75 μm Amplitude (vibration displacement) 2.58 V Vibration time 15 s Sample amount 5.0 g Sample was left overnight at 23 ° C. and 60% RH, and then left at 23 ° C.
The measurement is performed using a measuring device in an environment of 60% RH. A sample was introduced from the uppermost sieve 4, and the vibrations under the above conditions were given to the respective sieves 4, 5, and 6, and the weights G1, G2, and G3 of the samples remaining on the respective sieves were measured, and the following calculation formula was used. To obtain the liquidity index 求 め る. The value obtained by repeating the measurement five times and taking the arithmetic average is defined as the fluidity index Ψ.

[0082]

Ψ = G1 + G2 + G3 G1 = (weight of toner on sieve with openings of 250 μm / 5.
0) × 100 G1 = (weight of toner on sieve with mesh size of 150 μm / 5.
0) × 0.6 × 100 G1 = (weight of toner on sieve with mesh size of 75 μm / 5.0)
× 0.2 × 100 In the present invention, the weight average diameter of the toner (D ₄ ) X (μ
m) is preferably from 3.5 to 12.0. D ₄
Is smaller than the above range, the adhesion between the toners is increased, the angle of repose and the fluidity index are too large, and the desired value may not be obtained. If the value of D ₄ is excessively larger than the above range, there are cases where toner for small electrostatic latent image on the latent image bearing member is too large, it becomes pleasure not achieve high image quality.

The particle size distribution of the toner of the present invention can be measured using, for example, Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Inc.). As the electrolytic solution, a 1% NaCl aqueous solution prepared using primary sodium chloride can be used. Further, as this electrolytic solution, for example, ISOTON-II (manufactured by Coulter Scientific Japan) can be used. At the time of measurement, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution.
Add ~ 20 mg. The electrolyte in which the measurement sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the volume and the number of toner particles having a particle diameter of 2 μm or more are measured by the measuring device using an aperture of 100 μm as an aperture. I do.
From this, the volume distribution and the number distribution are calculated, and the weight-based weight average diameter (D ₄ : the median value of each channel is a representative value for each channel) calculated from the volume distribution according to the present invention is calculated. .

The toner contained in the developer of the present invention contains at least a binder resin, a magnetic substance, and a charge control agent. These constituent materials will be described in detail below.

As the binder resin for forming the toner that can be used in the present invention, conventionally known binder resins can be used. For example, polyester resins, vinyl resins, or epoxy resins can be used. preferable. Among these, it is particularly preferable to use a polyester resin, a vinyl-based resin, or a mixed resin of both, from the viewpoint of obtaining the effects of the present invention.

The polyester resin which can be used as the binder resin of the toner is usually obtained by polycondensation of polycarboxylic acid (generally dicarboxylic acid) as an acid component and polyhydric alcohol as an alcohol component. When used in the toner of the present invention, divalent carboxylic acids represented by the following general formulas (1) to (4) and monovalent carboxylic acids represented by the following formula (5) It is preferable to use, as the binder resin, one containing at least one of a carboxylic acid and a monohydric alcohol represented by the formula (6).

[0087]

Embedded image [In the formula, R ₁ represents a linear, branched or cyclic alkyl group or alkenyl group having 14 or more carbon atoms. R ₃ and R ₄ represent a hydrogen atom, a linear, branched or cyclic alkyl group or alkenyl group having 3 or more carbon atoms, and may be the same substituent, but are not hydrogen atoms at the same time. R ₅ and R ₆ represent a hydrogen atom, a linear, branched or cyclic alkyl group or alkenyl group having 3 or more carbon atoms, and may be the same substituent, but are not hydrogen atoms at the same time. R ₇ , R ₈
Represents a linear, branched or cyclic alkyl or alkenyl group having 12 or more carbon atoms. n represents an integer of 12 to 40. Examples of the compound represented by the formula (1) include compounds represented by the following formulas (1-1) to (1-6).

[0088]

Embedded image [(N) in the above formula indicates that the structure is linear. Examples of the compound represented by the formula (2) include compounds represented by the following formulas (2-1) to (2-4).

[0089]

Embedded image (2-1) HOOC- (CH ₂ ) ₁₄ -COOH (2-2) HOOC- (CH ₂ ) ₁₈ -COOH (2-3) HOOC- (CH ₂ ) ₂₄ -COOH (2-4) ) the HOOC- (CH ₂₎ a compound represented by ₃₄ -COOH formula (3), for example, those represented by the following formulas (3-1) to (3-3).

[0090]

Embedded image [(N) in the above formula indicates that the structure is linear. Examples of the compound represented by the formula (4) include compounds represented by the following formula (4-1) or (4-2).

[0091]

Embedded image Examples of the compound represented by the formula (5) include those represented by the following formulas (5-1) to (5-5).

[0092]

Embedded image _{(5-1) n-C 12 H} 25 -COOH (5-2) iso-C 12 H 25 -COOH (5-3) n-C 14 H 29 -COOH (5-4) n- the C ₂₀ H ₄₁ -COOH (5-5) compounds represented by n-C ₃₀ H ₆₁ -COOH (6), for example, those represented by the following formulas (6-1) to (6-5) No.

[0093]

Embedded image _{(6-1) n-C 12 H} 25 -OH (6-2) iso-C 12 H 25 -OH (6-3) n-C 14 H 29 -OH (6-4) n- _{C 20 H 41 -OH (6-5)} n-C 30 H 61 -OH Furthermore, as the component of the polyester resin used in the present invention, in addition to those mentioned above include the following.

As the alcohol component, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol,
1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, a bisphenol derivative represented by the following formula (A), and the following (B And diols represented by the formula:

[0095]

Embedded image Examples of the acidic component include benzenedicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid and anhydrides thereof; succinic acid, adipic acid, sebacic acid, and alkyldicarboxylic acids such as azelaic acid and anhydrides thereof;
Further, succinic acid or its anhydride substituted with an alkyl group having 6 to 18 carbon atoms; dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid;

In the present invention, the polyester resin used as the binder resin constituting the toner particles is 3
It is preferably cross-linked by a polyvalent carboxylic acid or polyhydric alcohol having a valency of at least 3, and trimellitic anhydride, benzophenonetetracarboxylic acid,
Pentaeristol and oxyalkylene ether of a novolak type phenol resin are preferred.

Further, in the toner of the present invention, the polyester resin used as a binder resin composed of the above components preferably has a glass transition temperature of 40 to 9 or less.
It is 0 degreeC, More preferably, it is 45-85 degreeC. Further, the number average molecular weight Mn of the polyester resin is preferably from 1,000 to 50,000, more preferably from 1,500 to 20,000. The weight average molecular weight Mw of the polyester resin is preferably 3,0.
00 to 100,000, more preferably 40,0.
00 to 90,000.

In the present invention, a homopolymer or copolymer of a vinyl monomer, polyester, polyurethane,
Epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, etc. can be used by mixing with the above-mentioned vinyl resin or polyester resin. .

As a more preferable form when two or more resins are mixed and used as a binder resin, it is preferable to mix resins having different molecular weights at an appropriate ratio.

The binder resin comprising the above components and the like used in the present invention further has an acid value of 3 to 30 mgKOH /
g and a hydroxyl value of 5 to 25 mgKOH / g. If the acid value is smaller than the above range, the chargeability of the toner may be low, and high image quality may not be obtained. On the other hand, if the acid value is larger than the above range, the chargeability of the binder resin becomes unstable, and fog may worsen. In this case, the acid value of the binder resin is J
It is a value measured by a method according to IS K-0070.

As a method of obtaining a vinyl resin as a binder resin constituting the toner of the present invention, a method of polymerizing a monomer constituting the vinyl resin may be mentioned.
The following are examples of monomers used in producing the vinyl resin.

For example, styrene; o-methylstyrene,
m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
styrene and its derivatives such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene; ethylene; Ethylenically unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated polyenes such as butadiene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate, vinyl propionate, and benzoate Vinyl esters such as vinyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, Α-methylene aliphatic monocarboxylic esters such as phenyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic N-octyl acid, dodecyl acrylate,
Acrylates such as 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether;
Vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone N-vinyl compounds; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide;
Examples thereof include esters of unsaturated acids and diesters of dibasic acids.

Also, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid and mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride Unsaturated dibasic acid anhydrides such as those; methyl maleate half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, methyl itaconate Half esters of unsaturated dibasic acids such as half ester, methyl alkenyl succinate half ester, methyl fumarate half ester and methyl half mesaconic acid; unsaturated dibasic acid esters such as dimethyl maleic acid and dimethyl fumaric acid; Acid, methacrylic acid, crotonic acid, such as cinnamic acid alpha, beta-unsaturated acid; crotonic acid anhydride, such as alpha of cinnamic acid anhydride, beta-unsaturated acid anhydride, the alpha, beta
-Anhydrides of unsaturated acids and lower fatty acids; and monomers having a carboxyl group such as alkenyl malonic acid, alkenyl glutaric acid, alkenyl adipic acid, acid anhydrides and monoesters thereof.

Further, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene 4- (1-hydroxy Monomers having a hydroxy group such as -1-methylhexyl) styrene are exemplified.

Examples of the polymerization initiator used for producing a vinyl resin include, for example, 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-
2,4-dimethylvaleronitrile), 2,2-azobis (-2,4-dimethylvaleronitrile), 2,2′-azobis (-2methylbutyronitrile), dimethyl-2,
2'-azobisisobutyrate, 1,1-azobis (1
-Cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile,
Ketone peroxides such as 2,2′-azobis (2-methyl-propane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclohexanone peroxide, 2,2-bis (t-butylperoxy) butane, t-butylhydro Peroxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, di-cumyl peroxide, α, α'-bis (T-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5
-Trimethylhexanoyl peroxide, benzoyl peroxide, m-trioil peroxide, di-
Isopropyl peroxydicarbonate, di-2-ethylhexylperoxydicarbonate, di-n-propylperoxydicarbonate, di-2-ethoxyethylperoxycarbonate, di-methoxyisopropylperoxydicarbonate, di- (3- Methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxyneodecanoate, t-butylperoxy2- Ethyl hexanoate, t-butyl peroxy laurate, t-butyl peroxy benzoate, t-butyl peroxy isopropyl carbonate,
Di-t-butylperoxyisophthalate, t-butylperoxyallyl carbonate, t-amylperoxy-2-ethylhexanoate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate Is mentioned.

The glass transition temperature of the vinyl binder resin is preferably from 45 to 80 ° C., more preferably from 55 to 70 ° C. The number average molecular weight Mn of the vinyl binder resin is preferably 2,500 to 50,000, and the weight average molecular weight Mw is 10,000 to 1,0.
More preferably, it is 00,000.

In the present invention, a homopolymer or copolymer of a vinyl monomer, polyester, polyurethane,
Epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, etc. are mixed with the above-mentioned vinyl resin as the binder resin as required. Can be used.

The toner of the present invention preferably contains a wax. Examples of the wax used in the toner of the present invention include the following, and these may be used alone or in combination. That is, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax; aliphatic hydrocarbon wax oxides such as oxidized polyethylene wax; block copolymers thereof; carnauba wax; Waxes containing fatty acid esters as main components such as sasol wax and montanic acid ester wax; and those obtained by partially or entirely deoxidizing fatty acid 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 brandic acid, eleostearic acid, and barinaric acid; stearin Saturated alcohols such as alcohols, aralkyl alcohols, behenyl alcohols, carnaubyl alcohols, seryl alcohols, melisyl alcohols, or long-chain alkyl alcohols having a longer-chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amide; Fatty acid amides such as oleic acid amide and lauric acid amide; methylene bisstearic acid amide;
Saturated fatty acid bisamides such as ethylene biscapric acid amide, ethylene bislauric acid amide, hexamethylene bis stearic acid amide, ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N '
Unsaturated fatty acid amides such as dioleyl adipic amide and N, N'-dioleyl sebacic amide; aromatic bisamides such as m-xylene bisstearic amide and N, N'-distearyl isophthalic amide Fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate (commonly referred to as metal soaps); grafting of vinyl monomers such as styrene and acrylic acid onto aliphatic hydrocarbon waxes Grafted waxes; partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols; and methyl ester compounds having a hydroxyl group obtained by hydrogenating vegetable oils and fats.

The amount of the wax used in the present invention is preferably from 0.1 to 20 parts by mass, more preferably from 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin. If the amount of wax is outside the above range, it will splatter, fog,
In some cases, the offset resistance and the like deteriorate, and a high-definition image cannot be obtained.

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

As a magnetic material, conventionally, triiron tetroxide (F
e_ThreeO_Four), Iron sesquioxide (γ-Fe_TwoO_Three), Zinc iron oxide
(ZnFeO_Four), Yttrium iron oxide (Y_ThreeFe
_FiveO₁₂), Cadmium iron oxide (CdFe_TwoO_Four),iron oxide
Gadolinium (GdFe_Five-O₁₂), Iron oxide copper (CuF
e_TwoO_Four), Lead iron oxide (PbFe₁₂-O₁₉), Iron oxide
Kel (NiFe_TwoO_Four), Iron neodymium oxide (NdFe
_TwoO_Three), Barium iron oxide (BaFe) ₁₂O₁₉), Iron oxide
Gnesium (MgFe_TwoO_Four), Iron manganese oxide (MnF)
e_TwoO_Four), Iron oxide lanthanum (LaFeO)_Three), Iron powder (F
e), cobalt powder (Co), nickel powder (Ni), etc.
However, in the present invention, the above-described magnetic material is used alone.
Alternatively, it can be selected and used in combination of two or more
You. Particularly preferred magnetic materials as the magnetic material of the present invention are 43
It is a fine powder of iron oxide or γ-iron sesquioxide.

The amount of the magnetic substance contained in the toner of the present invention is preferably from 10 to 200 parts by mass, more preferably from 50 to 180 parts by mass, per 100 parts by mass of the binder resin. If the content of the magnetic material is too large or too small, the high image quality may be difficult to achieve.

The toner used in the present invention is characterized by containing a charge control agent. By containing the charge control agent, the angle of repose of the toner and the waste toner can be set to a desired value, and the charge amount of the toner can be controlled according to other systems including the developing device, High image quality is achieved.

The charge control agent may be blended in the toner particles, that is, added internally. Further, it may be mixed with toner particles composed of a binder resin, a magnetic material, other additives, and the like, that is, may be externally added to the toner particles.

When the toner of the present invention has a negative triboelectric property,
As charge control agents, organometallic complex salts such as metal salicylate, metal alkylsalicylate, metal dialkylsalicylate and metal naphthoate; dyes such as monoazo dyes;
It preferably contains a monoazo dye derivative such as a metal complex salt of a monoazo dye.

In particular, examples of the negative charge control agent for the dye compound which can be used in the present invention include a monoazo iron complex salt represented by the following formula.

[0117]

Embedded image [Wherein X ₁ and X ₂ represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a nitro group or a halogen atom,
X ₁ and X ₂ may be the same or different, m and m ′ represent an integer of 1 to 3, Y ₁ and Y ₃ represent a hydrogen atom, C 1-18 alkyl, alkenyl, sulfonamide, Mesyl, sulfonic acid, carboxy ester, hydroxy, C 1-18 alkoxy, acetylamino, benzoylamino group or a halogen atom, Y ₁ and Y ₃ may be different, and n and n ′ are integers of 1 to 3 Represent
Y ₂ and Y ₄ represent a hydrogen atom or a nitro group, and A +
Represents a cation ion, having 75 to 98 mol% of ammonium ion, and additionally has hydrogen ion, sodium ion, potassium ion or a mixed ion thereof. Examples of the negative charge control agent for the complex salt compound that can be used in the present invention include an iron naphthoate complex represented by the following formula.

[0118]

Embedded image [In the formula, A + comprises an ammonium ion, an alkali metal ion or a hydrogen ion. B ₁ and B ₂ represent an alkyl group. In the case where the toner of the present invention has a positive triboelectrification property, as a charge control agent, a modified product such as nigrosine and a fatty acid metal salt; tributylbenzylammonium 1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, etc. Onium salts such as phosphonium salts and the like, and their lake pigments, triphenylmethane dyes and these lake pigments (the lake agents include phosphotungsten molybdic acid, tannic acid, lauric acid) , Gallic acid, ferricyanic acid, ferrocyanide, etc.), metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate; Guanidine compounds, imidazole compounds, aminoacrylic resins, and these can be used alone or in combination of two or more.

The content of the charge control agent is preferably from 0.1 to 5 parts by mass, more preferably from 0.2 to 3 parts by mass, based on 100 parts by mass of the binder resin in the toner. If the proportion of the charge control agent is too large, the fluidity of the toner deteriorates, so that the angle of repose of the toner and the waste toner becomes large, not to a desired value, and fog is liable to occur. On the other hand, if the charge control agent is too small, it is difficult to obtain a sufficient charge amount, and the angle of repose of the toner and the waste toner becomes small, and the image density becomes low.

The toner of the present invention may contain a colorant. As the coloring agent, carbon black, titanium white, and any other pigments and / or dyes can be used regardless of one component or two components.

The amount of the colorant used is 100
0.1 to 60 parts by mass, preferably 0.5 part by mass
５０50 parts by mass.

The toner of the present invention has environmental stability,
To improve charging stability, development stability, fluidity, and storage stability,
External additives may be mixed. It is preferable that inorganic fine powder or hydrophobic inorganic fine powder is mixed as such an external additive. For example, fine silica powder, fine titanium oxide powder, or a hydrophobized product thereof may be used. They are preferably used alone or in combination.

When a negatively chargeable silica fine powder is used, for example, the silica fine powder is surface-treated with dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, fluorine-modified silicone oil, or the like. May be.

When a finely-charged silica fine powder is used, it is preferable to treat with a silicone oil having an organo group having at least one nitrogen atom in a side chain, or a nitrogen-containing silane coupling agent.

As a method of treating with silicone oil, for example, silica fine powder treated with a silane coupling agent and silicone oil may be directly mixed using a mixer such as a Henschel mixer. Alternatively, after dissolving or dispersing the silicone oil in an appropriate solvent, the solvent may be removed by mixing with a base silica fine powder.

Among the above-mentioned fine silica powders, those having a specific surface area of 30 m ² / g or more (particularly 50 to 400 m ² / g) by nitrogen adsorption measured by the BET method are preferably used.

An external additive other than the silica fine powder or the titanium oxide fine powder may be added to the toner of the present invention, if necessary. For example, lubricants such as Teflon, zinc stearate, and polyvinylidene fluoride are preferable, and polyvinylidene fluoride is particularly preferable. Alternatively, cerium oxide, silicon carbide,
An abrasive such as strontium titanate, among which strontium titanate is preferred. Or, for example, titanium oxide,
Fluidity-imparting agents such as aluminum oxide, particularly hydrophobic ones are preferred. A small amount of an anti-caking agent, or a conductivity-imparting agent such as carbon black, zinc oxide, antimony oxide, or tin oxide, or white and black fine particles of opposite polarity can also be used as a developability improver.

The external additive mixed with the toner is used in an amount of 0.1 to 5 parts by mass (preferably 100 parts by mass of the toner).
0.1 to 3 parts by mass).

When the developer of the present invention is a magnetic two-component developer comprising a toner and a carrier, examples of the carrier usable in combination with the toner include iron powder, ferrite powder, magnetite powder, glass beads and the like. A non-coated carrier, a carrier coated with a styrene-acryl resin, a silicone resin, a fluorine-modified acrylic resin, or the like, a granulated carrier, or the like can be used.

In this case, 10 to 1000 parts by mass of the carrier (preferably 30 to 500 parts by mass) is added to 10 parts by mass of the toner.
(Parts by mass). The particle size of the carrier is 4 to 100 μm (preferably 10 to 80 μm,
(More preferably, 20 to 60 μm) is preferably used in matching with the toner of the present invention.

As a method for producing the toner constituting the developer of the present invention, a binder resin, a wax, a magnetic substance, or a charge control agent or other additives to be added as necessary are added to a Henschel mixer or a ball mill. The mixture is melted, kneaded and kneaded using a hot kneader such as a kneader or extruder to make the resins compatible with each other, and the resulting melt-kneaded product is cooled and solidified, and then solidified. Is ground, and if necessary, the ground matter is classified to obtain the toner of the present invention. As another method, a method of dispersing the above-described constituent materials in a binder resin solution and then spray-drying to obtain toner particles, or a method in which a monomer to constitute the binder resin has a predetermined material Are mixed to form an emulsified suspension and then polymerized to obtain a toner. Further, the toner of the present invention may be a microcapsule toner composed of a core material and a shell material.

Further, in the toner of the present invention, inorganic fine powder and other external additives such as a fluidizing agent are added to the toner particles obtained above, and the mixture is sufficiently mixed with a mixer such as a Henschel mixer. By mixing, the toner of the present invention in which an inorganic fine powder or the like is externally added to the surface of the toner particles can be obtained.

[0133]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. The number of parts in the examples is parts by weight.

Example 1 Production Example 1 of Developer 20 mol% of bisphenol A ethylene oxide adduct 20 mol% of bisphenol A propylene oxide adduct 25 mol% of terephthalic acid 25 mol% of fumaric acid 10 mol% of trimellitic acid Thermometer, so that each material has the above concentration
The flask was placed in a four-necked round bottom flask equipped with a stainless steel stirrer, a glass nitrogen inlet tube, and a falling condenser. Next, the flask was placed in a mantle heater, nitrogen gas was introduced from a glass inlet tube to keep the inside of the reaction vessel in an inert atmosphere, the temperature was raised, and a dehydration condensation reaction was performed at 220 to 250 ° C. After completion of the reaction, the mixture was cooled and solidified to obtain a polyester resin. The resulting polyester resin has an acid value of 2
7 mgKOH / g, glass transition point (Tg) was 57 ° C., number average molecular weight Mn was 10,500, and weight average molecular weight Mw was 42,000. This is referred to as resin 1.

Resin 1 100 parts Magnetic iron oxide 90 parts Monoazo iron complex salt 2 parts Polypropylene-polyethylene mixture (2: 8) 7 parts The above mixture was melt-kneaded with a biaxial extruder heated to 150 ° C., and cooled. The kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was further finely pulverized by a jet mill, and the obtained finely pulverized product was classified by a fixed wall type air classifier to produce a classified powder. Further, using a multi-segment classification device utilizing the Coanda effect (Elbow Jet Classifier manufactured by Nippon Steel Mining Co., Ltd.), ultrafine powder and coarse powder were simultaneously strictly classified and removed from the obtained classified powder to obtain a weight average diameter of 7 mm. 0.7 μm of magnetic toner particles were obtained. To 100 parts of the magnetic toner particles, 1.0 part of negatively charged hydrophobized silica fine particles and 3.0 parts of strontium titanate were externally added using a Henschel mixer.
A negatively chargeable magnetic toner (toner 1) as a magnetic one-component developer was obtained. Table 1 shows the material and physical properties of the toner 1. The repose angle Φ of this toner 1 at 23 ° C. and 60% RH is 25.0 °, and the fluidity index (Ψ) is 25.0%.
Met.

Examples 2 and 3 Developer Production Examples 2 and 3 Toner 2 was prepared in the same manner as in Example 1 except that the mixing ratio of the raw materials of the toner and the weight average diameter were changed as shown in Table 1. And Toner 3 were obtained. Table 1 shows the physical properties and the like of each toner.

Example 4 Production Example 4 of Developer 70 parts of styrene 15 parts of n-butyl acrylate 10 parts of monobutyl acrylate 5 parts of di-tert-butyl peroxide 5 parts In 200 parts of xylene heated to reflux temperature, The material was added dropwise over 4 hours. Furthermore, under xylene reflux (13
(8-144 ° C) to complete the polymerization and then under reduced pressure at 200 ° C
The xylene was removed while raising the temperature to obtain a styrene acrylic resin. This is called resin 2.

Resin 2 100 parts Magnetic iron oxide particles 90 parts Alcohol-modified polyethylene 5 parts Salicylic acid aluminum complex 2 parts The above mixture was melt-kneaded with a biaxial extruder heated to 130 ° C., and cooled. The kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was further finely pulverized by a jet mill, and the obtained finely pulverized product was classified by a fixed wall type air classifier to produce a classified powder. Further, using a multi-segmentation classifier utilizing the Coanda effect (Nippon Mining Co., Ltd. Elbow Jet Classifier), ultrafine powder and coarse powder were simultaneously strictly classified and removed from the obtained classified powder to obtain a weight average diameter of 6 mm. As a result, 0.5 μm magnetic toner particles were obtained. To 100 parts of the magnetic toner particles, 1.2 parts of negatively charged hydrophobized silica fine particles and 3.0 parts of strontium titanate were externally added using a Henschel mixer.
A negatively chargeable magnetic toner (toner 4) as a magnetic one-component developer shown in Table 1 was obtained. Table 1 shows the physical properties and the like of this toner.

<Examples 5 and 6> Examples 5 and 6 of Preparation of Developer Example 4 except that the mixing ratio of the wax, the charge control agent and the raw materials, and the weight average diameter of the toner were changed as shown in Table 1. Toner 5 and Toner 6 were obtained in the same manner as in.
Table 1 shows the physical properties and the like of each toner.

<Comparative Production Examples 1 and 2 of Toner> Wax,
Toners 7 and 8 were obtained in the same manner as in Example 4, except that the charge control agent, the mixing ratio of the raw materials, and the weight average diameter of the toner were changed as shown in Table 1. Table 1 shows the physical properties and the like of each toner.

<Comparative Production Example 3 of Toner> A method similar to that of Example 1 except that the mixing ratio of the wax, the charge control agent, the silica fine particles, and the raw materials, and the weight average diameter of the toner were changed as shown in Table 1. As a result, a toner 9 was obtained. Table 1 shows the physical properties and the like of this toner.

[0142]

[Table 1] Next, the produced toners 1 to 9 were evaluated by the following methods.

<Embodiment 7> Evaluation 1 As an electrophotographic apparatus (image forming apparatus), the developing device portion of a Canon digital copying machine GP40 was changed to GP4.
A copier modified so that a developing container having a volume larger than 0 can be used and the peripheral speed of the sleeve can be arbitrarily changed was used.

First, while replenishing the toner 1 to the developing device for examination (S1 = 10 cm ² , S2 / S1 = 6) as shown in FIG. A printout test was performed on 10,000 copies. At this time, the peripheral speed of the developer carrying member of the developing device was 252 mm / s. The obtained images were evaluated according to the following evaluation criteria. Table 2 shows the evaluation results. The same evaluation was performed in other examples and comparative examples described later, and the evaluation results are shown in Table 2.

In each of the examples, image evaluation was performed without separately adding a component (a hopper or the like) other than the collective replenishment developing device to the remodeled copying machine.

(1) Image Density Evaluation was performed by maintaining the image density at the end of printing out 300,000 sheets on ordinary plain paper for copying (75 g / m ² ). In addition,
The image density was determined by using a "Macbeth reflection densitometer" (manufactured by Macbeth) to measure the relative density of a 0.00% white background portion relative to the printout image.

(2) Fog Fog was calculated from a comparison between the whiteness of the transfer paper measured using a reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and the whiteness of the transfer paper after printing a solid white. .

(3) Image Quality Of the copied image, an approximately 2 mm square “den” character is observed with an optical microscope, and the level of sharpness of the character such as toner scattering around the “den” character is evaluated. did. In addition,
The symbols in Table 2 mean the following evaluations, respectively.

Δ: Sharp with little toner scattering around characters Δ: Slightly toner scattering X: Lots of toner scattering (4) Toner replenishment (non-shake properties) Toner is stored from toner container in second toner When the developer was supplied to the chamber, the non-shake property was judged and evaluated by the number of times the developing device was vibrated to correct the bias of the toner surface layer. Table 2
Each symbol in the table means the following evaluation.

〇: 0 times to 1 time △: 2 times to 5 times ×: 6 times or more (5) Total copy number elongation rate per replenishment Continuous using a document with a printing ratio of 6% at normal temperature and normal humidity When a print durability test was performed, S1 was 6 cm ² , S2 / S1
Is less than the total number of copies when the developing device configuration of 4.0 is used, and the number of copies after the lamp for notifying that the developer in the developing device is low is turned on by the developer remaining amount detecting means. The total copy number elongation rate was evaluated based on the ratio of whether or not. The symbols in Table 2 mean the following evaluations, respectively.

Δ: 150% or more Δ: 101% to 150% ×: Less than 101% (6) Image characteristics before and after toner replenishment Image density before and after toner replenishment (ΔD = image density before replenishment−after replenishment) 20 after replenishment of image density) and white spots
A total of 0 image samples were comprehensively evaluated and evaluated.

〇: ΔD <0.05 No white spot Δ: ΔD = 0.05 to 0.10 Minor white spot ×: ΔD> 0.10 High white spots The evaluation results of the above (1) to (6) are shown in the table. 2 is shown.

<Examples 8 to 12> Evaluations 2 to 12 Same as Example 7 except that S1 and S2 / S1 of the developing device, the peripheral speed of the developer carrying member, and the toner were changed as shown in Table 2. The evaluation was performed according to the following method.

<Comparative Examples 1-4> S1 and S of the developing device
The evaluation was performed in the same manner as in Example 7, except that 2 / S1, the peripheral speed of the developer carrying member, and the toner were changed as shown in Table 2.

[0155]

[Table 2]

[0156]

As described above, by using the image forming method and the toner of the present invention, the toner replenishing property is excellent and the total number of copies per toner replenishment can be increased.
Further, it is possible to provide an image forming method which enables output of a high-definition image even before and after toner replenishment.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a specific example of a developing device used in the present invention.

FIG. 2 is a cross-sectional area of a first toner storage chamber in a vertical section near the center of the axis of a developing sleeve of the developing device of FIG. 1, and a developer supply chamber of a second toner storage chamber;
Schematic explanatory diagram for obtaining S1 and S2 / S1 when the sectional area of S2 is S2

FIG. 3 is a schematic explanatory view showing a state of a developing device before and after replenishment of a developer (toner).

FIG. 4 is a schematic diagram for explaining the image forming method of the present invention.

FIG. 5 is a schematic explanatory view of an apparatus for measuring a repose angle of a developer (toner).

FIG. 6 is a schematic explanatory view of an apparatus for measuring a fluidity index of a developer (toner).

[Explanation of symbols]

 Reference Signs List 1 sieve with opening 710 μm 2 funnel 3 disk 4 sieve with opening 250 μm 5 sieve with opening 150 μm 6 sieve with opening 75 μm 7 shaking table 110 latent image carrier (photosensitive drum) 111 developing device 112 first storage chamber (developing) Chamber) 113 second storage chamber (developer supply chamber) 114 partition member 115 developer carrier (developing sleeve) 116 magnet 117 doctor blade 118 first stirring and conveying means 119 second stirring and conveying means 120 one-component developer (toner) 121) Developer residual amount detecting means 122 Toner supply port 123 Toner cartridge 131 Primary charger 132 Exposure system 133 Bias applying means 134 Transfer charger 135 Conveyor belt 136 Heat and pressure fixing device 137 Cleaning blade 138 Cleaner 139 Erase exposure 140 Transfer Equipment P Transfer paper

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03G 9/083 G03G 9/08 331 9/087 344 9/097 15/08 507E 507L

Claims (6)

[Claims] 1. A toner image is formed on a latent image carrier by visualizing an electrostatic latent image carried on the latent image carrier with toner contained in a developer filled in a developing device. An image forming method for transferring the toner image to a transfer material and fixing the toner image transferred to the transfer material to the transfer material, wherein the developing device comprises: a first device for storing the developer; An accommodating chamber, a second accommodating chamber accommodating the developer and communicating with the first accommodating chamber, and a side surface facing the latent image carrier and supporting the developer. A developer for transporting the developer to a developing area, which is the closest part between the support surface and the image carrier, by rotating the cylinder around a central axis of the cylinder as a rotation axis. A carrier, disposed in the first storage chamber, and in the first storage chamber A first agitating / conveying means for agitating the contained developer along a rotation axis direction of the developer carrier, and transporting the developer to the developer carrier; And a second stirring / transporting unit for stirring and transporting the developer contained in the second storage chamber to the first storage chamber. The sectional area of the first storage chamber in the vertical section near the center is S1,
When the sectional area of the second storage chamber is S2, S1 is 6
１８18 cm ² and the ratio of S2 to S1 (S
2 / S1) is 4.2 to 8.2, and the toner contained in the developer contains at least a binder resin, a magnetic material, and a charge control agent, and has a temperature of 2
The angle of repose in an environment of 3 ° C. and a relative humidity of 60% is 5 to 3
An image forming method, wherein the angle is 5 ° and the fluidity index (cohesion degree) in the above environment is 3 to 35%. 2. A peripheral speed of the developer carrier is 80 mm / s.
2. The image forming method according to claim 1, wherein: 3. The toner according to claim 1, wherein the toner has a weight average diameter of 3.5 to 1.
The image forming method according to claim 1, wherein the thickness is 2.0 μm. 4. The toner according to claim 1, wherein the binder resin of the toner contains at least a polyester resin.
The image forming method according to any one of the above. 5. A developer for visualizing an electrostatic latent image carried on a latent image carrier, comprising at least a toner containing a binder resin, a magnetic material, and a charge control agent. The toner has an angle of repose of 5 to 35 ° in an environment at a temperature of 23 ° C. and a relative humidity of 60%, and a fluidity index (cohesion degree) in the environment of 3 to 35%. Developer. 6. A developing device for visualizing an electrostatic latent image carried on a latent image carrier, a first accommodating chamber for accommodating the developer according to claim 5, and the developer. And a second storage chamber that communicates with the first storage chamber, and has a cylindrical shape that is arranged to face the latent image carrier and has a side surface that is a support surface that supports the developer. A developer carrier for transporting the developer to a development area which is a closest portion between the carrier surface and the image carrier by rotating the central axis of the cylinder as a rotation axis; A first container disposed in the storage chamber and configured to stir the developer stored in the first storage chamber along a rotation axis direction of the developer carrier and to convey the developer to the developer carrier; Stirring and conveying means, disposed in the second storage chamber, and stored in the second storage chamber. A second stirring / transporting unit for stirring and transporting the developer to the first storage chamber; and a cross-sectional area of the first storage chamber in a vertical cross section near the center of the central axis of the developer carrier. Is S1, and when the cross-sectional area of the second storage chamber is S2, S1 is 6 to 18 cm ²
And a ratio of S2 to S1 (S2 / S1) is 4.2 to 8.2.