JP2005099775A - Color image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color image forming method which is good in cleanability even if spherical toners and a blade cleaning system are used. <P>SOLUTION: The image forming method comprises a step of fixing the toner images superposed and transferred onto a transfer member by heat and pressure by performing a series of steps consisting of a step of electrostatically charging an electrostatic latent image carrier, a step of forming the electrostatic latent images separated in colors to the electrostatic latent image carrier, a step of developing the electrostatic latent image in a developing section for developing the first electrostatic latent image housing the color toners, a step of transferring the developed first toner image to the transfer member, and a step of cleaning the electrostatic latent image carrier after the transfer of the first toner image, successively relating with four colors. The spherical toner of 0.94 to 0.99 in circularity is used for the toner of one or more colors among the toners of the respective colors and the unshaped toner of 0.85 to 0.93 in circularity is used for the toner of the other one or more colors. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color image forming method for forming a color image by electrophotography using color toner.

In general, spherical toners used for electrophotography have good resolution and good toner transfer properties, and in recent years, color polymerization toners have been actively commercialized. Such a spherical toner has a poor cleaning property because the residual toner slips through the edge portion in the blade cleaning method in which the elastic body is brought into contact with the latent image carrier in the cleaning process and the residual toner is scraped off at the edge portion of the elastic body. (Non-Patent Documents 1 and 2).
Proposals for improving the above-described cleaning properties have been made, and examples thereof will be introduced below.

(Patent Document 1)
An image carrier on which a latent image is formed, a developing device that develops the latent image with spherical toner to form a toner image, an intermediate transfer member on which the toner image on the image carrier is once transferred, and a post-transfer In an image forming apparatus provided with a cleaning blade for removing residual transfer toner, an irregular shape particle is supplied to the intermediate transfer member, and the irregular shape particle is supplied to the cleaning blade via the intermediate transfer member. It is described that by providing the regular particle supply means, the cleaning property of the spherical toner in the blade cleaning is improved.

(Patent Document 2)
In an image forming method using a color developer comprising a combination of a yellow toner, a magenta toner and a cyan toner containing a colorant-containing resin particle and an external additive, and a black toner containing a magnetic resin particle and the external additive. It describes that a stable cleaning characteristic can be obtained by using a flow improver and organic resin particles having a particle size of at least 20 to 200 mμ and 300 to 800 mμ as external additives.

(Patent Document 3)
It describes that the cleaning property by the cleaning blade is improved by mixing spherical particles and irregular particles in the toner particles.

(Patent Document 4)
Use specific toner external additives and improve the cleaning performance of the cleaning blade by ensuring that the volume average diameter, number%, and volume average particle diameter of the toner particles satisfy a specific formula. Is described.

(Patent Document 5)
As the latent image carrier, an organic photoreceptor containing a fluororesin powder on the surface layer thereof, a toner having substantially spherical toner particles as a developer and an external additive containing a fluidity-imparting agent It is described that the toner particles have a specific uneven structure to improve the cleaning property by blade cleaning.

JP 2001-166659 A Japanese Patent Laid-Open No. 05-249741 Japanese Patent Laid-Open No. 11-0665163 Japanese Patent No. 2704766 Japanese Patent No. 3230006 Annual Meeting of the Electrophotographic Society (68 times in total) “Japan Hardcopy '92” Proceedings, Sponsored by the Electrophotographic Society, p. 101, “Powder characteristics of pulverized and suspension polymerized toner” (Ochiai et al.) Annual Meeting of the Electrophotographic Society (67 times in total), “Japan Hardcopy '91” Proceedings, Sponsored by the Electrophotographic Society, p. 21, “Adaptive technology of polymerized toner to non-magnetic one-component process” (Takezawa et al.)

SUMMARY OF THE INVENTION An object of the present invention is to provide a color image forming method using a spherical color toner, which can achieve good cleaning performance even when the cleaning step is a blade cleaning method.
Another object of the present invention is to provide a process cartridge used in an image forming apparatus that performs the image forming method.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained the following knowledge.
There are four independent image forming units, and there are charging, exposure, development, intermediate transfer, and cleaning processes around each electrostatic latent image carrier. In the developing portions of the four image forming portions, at least one or more toners having an irregular shape with a circularity of 0.85 to 0.94 are stored.

  When the four independent image forming portions are observed closely, for example, a two-component developer made of an irregular toner is set in the first image forming portion, and the latent image is developed with the agent. The toner developed by the first image forming unit is temporarily transferred to the intermediate transfer member. The intermediate transfer member to which the toner image has been transferred proceeds to the next second image forming unit. At that time, the toner image is not developed in the second, third, and fourth image forming portions (the toner is not attached to the latent image carrier), and only the intermediate transfer member on which the toner transferred on the first image forming portion is placed passes. Let

  The toner developed in the first image forming unit forms a first image on the surface of each of the second, third and fourth latent image carriers immediately after passing through the latent image carrier of the second, third and fourth image forming units. It was confirmed that the toner developed in the area was reversely transferred. This toner enters the cleaning section of each of the second, third, and fourth image forming sections, and becomes in a form in which irregular toner is accumulated at the tip of the cleaning blade. Since such irregular toner is subjected to blade cleaning in the cleaning process, irregular toner is collected at the blade edge portion. As a result, indefinite toner is collected at the blade edge portion of the cleaning portion of each image forming portion. For this reason, the toner cannot pass through the blade edge portion, so that no cleaning failure occurs. In such a state, even if spherical toner that has not been transferred enters the cleaning portion, cleaning is performed satisfactorily, so that no cleaning failure occurs.

  As a toner color for making the toner particles indefinite, a yellow toner whose resolution is not conspicuous with a single color or a black toner having a high degree of copying a black document even in a color image forming apparatus is preferable. Keeping the shape indefinite gives good results. As described above, when there is at least one amorphous toner among the four color toners, the contact area of the toner layer on the intermediate transfer member, for example, in the first image forming portion, compared with the spherical transfer toner, on the intermediate transfer member. Therefore, the toner layer to be transferred next (second layer, third layer, or fourth layer) can be stably overlaid and transferred. (The second layer, the third layer, and the fourth layer are less likely to generate avalanches.) Also, even if the amorphous toner is the second layer, the third layer, or the fourth layer, the contact between the toners is a spherical toner. It becomes larger than that, and it becomes difficult to cause avalanche of the toner layer. As a result, it is possible to maintain good image quality such as image flow, image dust, sharpness, and background stains.

  In an apparatus using an intermediate transfer member, it is necessary to transfer toner at least twice when transferring to the final transfer member. To prevent image deterioration as much as possible during transfer, irregular toner is mixed to prevent deterioration during transfer. To do. On the other hand, if all toners are irregular, the blade cleaning is good, but the sharpness and halftone reproduction are not good. Also, if all four colors are spherical toners, the toners will be rolled easily, and the avalanche phenomenon will easily occur. Therefore, the image quality will not be good, and cleaning defects will also occur. If the irregular toner particle size is made larger than that of the other toners, the toner can be prevented from slipping by the toner at the tip of the blade, and as a result, the cleaning property is further improved.

The inventors have completed the present invention based on the above findings.
That is, the present invention is as follows.

(1) charging the first electrostatic latent image carrier, forming a color-separated electrostatic latent image on the first electrostatic latent image carrier, and storing the color toner A A step of developing the electrostatic latent image in a developing unit that develops the electrostatic latent image, a step of transferring the developed first toner image to a transfer member, and the electrostatic latent image carrier after transferring the first toner image A step of cleaning the second electrostatic latent image carrier, a step of forming a color-separated electrostatic latent image on the second electrostatic latent image carrier, and storing the color toner B A step of developing the electrostatic latent image in a developing unit that develops the second electrostatic latent image, a step of transferring the developed second toner image onto the transfer member onto which the first toner image is transferred, A step of cleaning the electrostatic latent image carrier after transferring the toner image, a step of charging the third electrostatic latent image carrier, and a third static image Forming a color-separated electrostatic latent image on the latent image bearing member; developing a third electrostatic latent image containing color toner C; developing the electrostatic latent image; A step of superimposing and transferring the third toner image onto the transfer member to which the second toner image is transferred, a step of cleaning the electrostatic latent image carrier after transferring the third toner image, and a fourth electrostatic latent image. Charging the carrier, forming a color-separated electrostatic latent image on the fourth electrostatic latent image carrier,
Developing the electrostatic latent image in a developing unit for developing the fourth electrostatic latent image containing the color toner D, and transferring the developed fourth toner image onto the transfer member to which the third toner image is transferred. An image forming method comprising: a step of cleaning the latent electrostatic image bearing member after transferring a fourth toner image; and a step of fixing the toner images successively transferred onto the transfer member by heat and pressure. One or more of the toners of each color of A, B, C, and D is a spherical toner having a circularity of 0.94 to 0.99, and the other one or more of the toners has a circularity of 0.85 to 0.00. 93. A color image forming method, wherein the toner is 93 irregular toner.

(2) A step of charging the first electrostatic latent image carrier, a step of forming a color-separated electrostatic latent image on the first electrostatic latent image carrier, and developing the first electrostatic latent image The step of developing the electrostatic latent image by storing the color toner A in the developing unit, the step of temporarily transferring the developed first toner image to the intermediate transfer member, and the electrostatic image after transferring the first toner image Cleaning the latent image carrier, then charging the second electrostatic latent image carrier, forming a color-separated electrostatic latent image on the second electrostatic latent image carrier, The step of developing the electrostatic latent image by storing the color toner B in the developing unit that develops the electrostatic latent image 2, the developed second toner image is temporarily transferred to the intermediate transfer member to which the first toner image is transferred. A step of superimposing, a step of cleaning the latent electrostatic image bearing member after the second toner image is transferred, and then applying a belt to the third latent electrostatic image bearing member. A step of forming a color-separated electrostatic latent image on a third electrostatic latent image carrier, and a color toner C is stored in a developing unit for developing the third electrostatic latent image. A step of developing the image, a step of temporarily transferring the developed third toner image onto the intermediate transfer member to which the second toner image has been transferred, and a step of transferring the third latent toner image after transferring the third toner image. Cleaning, then charging the fourth electrostatic latent image carrier, forming a color-separated electrostatic latent image on the fourth electrostatic latent image carrier, fourth electrostatic latent image The step of developing the electrostatic latent image by storing the color toner D in the developing unit for developing the image, and the step of temporarily transferring the developed fourth toner image to the intermediate transfer member to which the third toner image is transferred. And a step of cleaning the latent electrostatic image bearing member after transferring the fourth toner image, and sequentially superimposing it on the intermediate transfer member. The copied toner image is formed by an image forming method including a step of transferring the toner image to transfer paper and fixing it by heat and pressure. One or more of the toners of A, B, C, and D colors has a circularity of 0.94. A color image forming method, wherein the toner is a spherical toner having ˜0.99 and the other one is an irregular toner having a circularity of 0.85˜0.93.
(3) The color image forming method as described in (1) or (2) above, wherein the step of cleaning the electrostatic latent image carrier after the transfer step is performed by a blade cleaning method.
(4) The color image forming method as described in (1) to (3) above, wherein the toner particle binder resin is polyester.
(5) The color image forming method as described in (1) to (4) above, wherein the toner particle binder resin is a polyol.
(6) The color image forming method as described in (1) to (5) above, wherein the toner particles contain a release agent.
(7) The color image forming method as described in (1) to (6) above, wherein the irregularly shaped toner particles are black toner.
(8) The color image forming method as described in (1) to (7) above, wherein the step of charging the electrostatic latent image carrier is performed by a roller charging member.
(9) The color image forming method as described in (1) to (8) above, wherein the toner is fixed in the fixing step by a pair of rollers with a fixing belt interposed.

(10) The color image forming method as described in (1) to (9) above, wherein an alternating electric field is applied when developing the latent image on the electrostatic latent image carrier.
(11) The color image forming method as described in (1) to (10) above, wherein the electrostatic latent image carrier is an amorphous silicon photoconductor.
(12) A fixing device used in the fixing step includes a heating body provided with a heating element, and a pressure member that presses the heating body through a film that contacts the heating body, and the film and the The fixing device according to (1) to (8), (10), or (11) above, wherein the fixing device heats a recording material on which an unfixed image is formed between pressure members. Color image forming method.
(13) A fixing device used in the fixing step is composed of a magnetic metal and heated by electromagnetic induction, a fixing roller arranged in parallel with the heating roller, the heating roller, and the fixing roller. And an endless belt-like toner heating medium that is heated by the heating roller and rotated by these rollers, and is pressed against the fixing roller via the toner heating medium, and also against the toner heating medium The color image forming apparatus according to any one of (1) to (8), (10), and (11), wherein the fixing device includes a pressure roller that rotates in a forward direction to form a fixing nip portion. Method.
(14) A process cartridge used in an image forming apparatus main body for performing the color image forming method according to any one of (1) to (7) above, comprising an electrostatic latent image carrier, a charging unit, a developing unit, A process cartridge which integrally supports at least one means selected from cleaning means and is detachable from an image forming apparatus main body.

  When the color image forming method of the present invention is used, a good cleaning property can be obtained by using an irregular toner and a spherical toner at the same time for forming a color image, particularly when a blade cleaning method is used. Spherical and amorphous toners can be easily obtained by simple surface treatment in the toner production stage, and the method of the present invention is useful.

  An image forming apparatus for carrying out the image forming method of the present invention will be described with reference to the drawings.

<Image Forming Apparatus (Part 1)>
FIG. 1 shows an example of an image forming apparatus for carrying out the image forming method of the present invention, and this apparatus has four independent image forming units.
First, in the first image forming unit, the latent image carrier 1A rotates clockwise. The latent image carrier 1A is uniformly charged by the charging member 2A. Subsequently, an electrostatic latent image color-separated by exposure 3A is formed on the latent image carrier 1A. The formed electrostatic latent image is developed in the developing area of the developing unit 4A. A two-component developer is stored in the developing unit 4A.

  A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, the latent image carrier 1 </ b> A rotates and transfers the toner image on the latent image carrier 1 </ b> A onto the transfer paper 8 by the transfer unit 5 </ b> A via the transfer paper 8 conveyed by the conveyance belt 7. The latent image carrier 1A rotates and proceeds to the cleaning unit 6A to clean the toner that has not been transferred and proceeds to the next charging member 2A.

  The transfer paper 8 onto which the toner image has been transferred is conveyed to the next second image forming unit. Next to the first image forming unit, the latent image carrier 1B rotates clockwise in the second image forming unit. The latent image carrier 1B is uniformly charged by the charging member 2B. Subsequently, an electrostatic latent image color-separated by exposure 3B is formed on the latent image carrier 1B.

  The formed electrostatic latent image is developed in the development area of the development unit 4B. The developing unit 4B contains a two-component developer. A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, the latent image carrier 1B is rotated and transferred onto the latent image carrier 1B by the transfer unit 5B via the transfer paper 8 having the toner image transferred by the first image forming unit conveyed by the conveyance belt 7. The toner image is transferred onto the transfer paper 8. The latent image carrier 1B rotates and proceeds to the cleaning unit 6B to clean the toner that has not been transferred, and proceeds to the next charging member 2B.

  The transfer paper 8 onto which the toner image has been transferred is conveyed to the next third image forming unit. Next to the second image forming unit, the latent image carrier 1C is rotated clockwise in the third image forming unit. The latent image carrier 1C is uniformly charged by the charging member 2C. Subsequently, an electrostatic latent image color-separated by exposure 3C is formed on the latent image carrier 1C. The formed electrostatic latent image is developed in the developing area of the developing unit 4C.

  A two-component developer is stored in the developing unit. A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, the latent image carrier 1C is rotated and transferred onto the latent image carrier 1C by the transfer unit 5C via the transfer paper 8 having the toner image transferred by the second image forming unit conveyed by the conveyance belt 7. The toner image is transferred onto the transfer paper 8. The latent image carrier 1C rotates and proceeds to the cleaning unit 6C to clean the toner that has not been transferred, and proceeds to the next charging step 2C.

  The transfer paper 8 onto which the toner image has been transferred is conveyed to the next fourth image forming unit. Next to the third image forming section, in the fourth image forming section, the 1D latent image carrier 1D is rotated clockwise. The latent image carrier 1D is uniformly charged by the charging member 2D. Subsequently, an electrostatic latent image color-separated by exposure 3D is formed on the latent image carrier 1D. The formed electrostatic latent image is developed in the developing area of the developing unit 4D.

  The developing unit 4D stores a two-component developer. A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, the latent image carrier 1D is rotated and transferred onto the latent image carrier 1D by the transfer unit 5D via the transfer paper 8 having the toner image transferred by the third image forming unit conveyed by the conveyance belt 7. The toner image is transferred onto the transfer paper 8.

  The latent image carrier 1D rotates and proceeds to the cleaning unit 6D to clean the toner that has not been transferred, and proceeds to the next charging member 2D. The transfer paper 8 onto which the toner image has been transferred is conveyed to a fixing unit (not shown) to fix the toner image. The conveyor belt 7 with the transfer paper 8 released is cleaned by the conveyor belt cleaning unit 9 to prepare for the next transfer paper 8 conveyance.

<Image forming apparatus (part 2)>
FIG. 2 shows an example of an image forming apparatus for carrying out the image forming method of the present invention, and this apparatus has four independent image forming units.
First, in the first image forming unit, the 1A latent image carrier is rotated clockwise. This 1A is uniformly charged by a 2A charging member. Subsequently, an electrostatic latent image subjected to color separation by 3A exposure is formed on the 1A latent image carrier. The formed electrostatic latent image is developed in the development area of the 4A development section. A two-component developer is stored in the developing unit. A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, 1A is rotated and the toner image on 1A is transferred to 7 by the transfer portion 5A on the intermediate transfer member 7 that is rotating leftward. 1A rotates and proceeds to the cleaning unit 6A to clean the toner that has not been transferred, and proceeds to the next charging step 2A. 7 to which the toner image has been transferred is conveyed to the next second image forming unit.

  After the first image forming unit, the latent image carrier 1B is rotated clockwise in the second image forming unit. This 1B is uniformly charged by a 2B charging member. Subsequently, an electrostatic latent image subjected to color separation by 3B exposure is formed on the 1B latent image carrier. The formed electrostatic latent image is developed in the development area of the development section 4B. A two-component developer is stored in the developing unit. A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, 1B is rotated and the toner image on 1B is transferred to 7 at the transfer portion 5B of the intermediate transfer member 7 where the toner image transferred at the first image forming portion is present. 1B rotates and proceeds to the cleaning unit 6B to clean the toner that has not been transferred, and proceeds to the next charging step 2B. 7 to which the toner image has been transferred is conveyed to the next third image forming unit.

  Next to the second image forming unit, the 1C latent image carrier is rotated clockwise in the third image forming unit. This 1C is uniformly charged by a 2C charging member. Subsequently, an electrostatic latent image subjected to color separation by 3C exposure is formed on the 1C latent image carrier. The formed electrostatic latent image is developed in the development area of the 4C development section. A two-component developer is stored in the developing unit. A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, 1C is rotated and the toner image on 1C is transferred to 7 via intermediate transfer member 7 having the toner image transferred at the second image forming unit via transfer unit 5C. 1C rotates and proceeds to the cleaning unit 6C to clean the toner that has not been transferred, and proceeds to the next charging step 2C. The toner image 7 is transferred to the next fourth image forming unit.

  Next to the third image forming unit, the 1D latent image carrier is rotated clockwise in the fourth image forming unit. This 1D is uniformly charged by a 2D charging member. Subsequently, an electrostatic latent image subjected to color separation by 3D exposure is formed on the 1D latent image carrier. The formed electrostatic latent image is developed in the developing area of the 4D developing unit. A two-component developer is stored in the developing unit. A developer is supplied from a supply roller (not shown) to the developing sleeve to develop the electrostatic latent image. Thereafter, 1D is rotated, and the toner image on 1D is transferred to 7 through intermediate transfer member 7 having the toner image transferred by the third image forming unit via transfer unit 5D. 1D rotates and proceeds to cleaning unit 6D to clean the toner that has not been transferred, and proceeds to the next charging step 2D. The toner image 7 transferred and transferred is further rotated and transferred to the transfer paper 8 through the transfer unit 10 at once. Thereafter, 8 is conveyed to a fixing unit (not shown) to fix the toner image. After the toner is transferred to the transfer paper 8, the intermediate transfer member 7 cleans the surface of the intermediate transfer member by the intermediate transfer member cleaning unit 9 to prepare for the next intermediate transfer.

Next, the charging method used in the image forming apparatus of the present invention will be described.
The shape of the charging member used in the present invention may take any form such as a roller, a fur brush, and a magnetic brush, and can be selected according to the specifications and form of the electrophotographic apparatus.
Hereinafter, roller charging, fur brush charging, and magnetic brush charging will be described.

<Roller electrification>
A configuration example of roller charging will be described with reference to FIG.
FIG. 3 shows a schematic configuration of an example of an image forming apparatus using a contact-type charging device.
The electrostatic latent image carrier 1 to be charged is rotated at a predetermined speed (process speed) in the direction of the arrow. The roller charger 2 which is a charging member brought into contact with the electrostatic latent image carrier 1 has a core metal 3 and an elastic layer 4 formed concentrically and integrally on the outer periphery of the core metal 3 as a basic structure. A protective layer 5 is provided on the layer 4, and both ends of the cored bar 3 are rotatably held by a bearing member (not shown) or the like, and are pressed against the photosensitive drum with a predetermined pressure by a pressing means (not shown). In the case of this figure, the roller charger 2 rotates following the rotation of the electrostatic latent image carrier 1. The roller charger 2 is formed to have a diameter of 16 mm by covering a core metal 3 having a diameter of 9 mm with a medium resistance rubber layer of about 100,000 Ω · cm.

  The metal core 3 of the roller charger 2 and the illustrated high voltage power source 10 are electrically connected, and a predetermined bias is applied to the charging roller by the high voltage power source 10. As a result, the peripheral surface of the electrostatic latent image carrier 1 is uniformly charged to a predetermined polarity and potential. Further, in this figure, a DC voltage is applied to the roller charger 2 by the high-voltage power supply 10, but an AC voltage superimposed on the DC voltage may be used.

The roller charger 2 rotates in a state of being lifted from the electrostatic latent image carrier 1 or in pressure contact with the roller charger 2 to form an appropriate nip, thereby stabilizing the discharge. As the material of the elastic layer 4, a modified type ethylene propylene rubber (EPDM), urethane rubber, epichlorohydrin rubber, or nitrile rubber whose resistance is easily controlled is used for the elastic layer 4. This layer controls the resistance value (10 ⁶ to 10 ¹⁰ Ωcm) by adding a low resistance material such as carbon.

  The protective layer 5 has abrasion resistance, protects the elastic layer, is chemically stable and does not react with the electrostatic latent image carrier 1 and the toner, and does not adhere dirt such as toner or paper dust. Desired. As the material, high resistance products of various films are used. On the protective layer 5, there is a cleaning member 6, which is made of a material that is less releasable than the surface of the protective layer 5, so that the dirt on the surface of the protective layer 5 is transferred to the cleaning member 6.

<Fur brush charging>
FIG. 4 shows a schematic configuration of an example of an image forming apparatus using a contact-type charging device. The electrostatic latent image carrier 1 is rotationally driven in the direction of the arrow at a predetermined speed (process speed). A brush roller 12 composed of a fur brush 11 is brought into contact with the electrostatic latent image carrier 1 with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion.

  The fur brush roller 12 as a contact charging member in this example spirals a tape made of a conductive core rayon fiber REC-B manufactured by Unitika Co., Ltd. as a brush portion on a metal core 13 having a diameter of 6 mm which also serves as an electrode. The roll brush has an outer diameter of 14 mm and a longitudinal length. The brush of the brush part has a density of 300 denier / 50 filaments and 155 per square millimeter. This roll brush was inserted into a pipe having an inner diameter of 12 mm while rotating in one direction, and the brush and the pipe were set to be concentric, and left in a high-temperature and high-humidity atmosphere to bend and bevel.

The resistance value of the fur brush roller is 1 × 10 ⁵ Ω at an applied voltage of 100V. This resistance value was converted from the current that flows when a fur brush roller is brought into contact with a metal drum having a diameter of 30 mm with a nip width of 3 mm and a voltage of 100 V is applied. The resistance value of the fur brush charger is such that, even when a low-voltage defective part such as a pinhole occurs on the photosensitive member that is the object to be charged, an excessive leakage current flows into this part and the charging nip part becomes poorly charged. In order to prevent image defects, it is necessary to be 10 ⁴ Ω or more, and in order to sufficiently inject charges onto the surface of the photoreceptor, it is necessary to be 10 ⁷ Ω or less.

  In addition to REC-B manufactured by Unitika Ltd., the material of the brush is REC-C, REC-M1, REC-M10, SA-7 manufactured by Toray Industries, Inc., Sanderlon, Kanebo It is possible to use a beltron manufactured by Kuraray Co., Ltd., a Kuraray Krakabo, a carbon dispersion in rayon, or a global manufactured by Mitsubishi Rayon Co., Ltd. One brush is 3 to 10 denier, and preferably has a density of 10 to 100 filaments / bundle and 80 to 600 brushes / mm. The hair foot is preferably 1 to 10 mm.

  The fur brush roller 12 is rotationally driven at a predetermined peripheral speed (surface speed) in a direction opposite to the rotation direction (counter) of the electrostatic latent image carrier 1 and has a speed difference with respect to the surface of the electrostatic latent image carrier. Touch. By applying a predetermined charging voltage from the power source 14 to the fur brush roller 12, the surface of the rotating electrostatic latent image carrier is uniformly contact-charged to a predetermined polarity and potential. In this example, the electrostatic charging of the electrostatic latent image carrier 1 by the fur brush roller 12 is performed by direct injection charging, and the surface of the rotating electrostatic latent image carrier is applied with the charging voltage applied to the fur brush roller 12. Charged to approximately the same potential.

<Magnetic brush charging>
In the case of magnetic brush charging, the basic charging device configuration is the same as that shown in FIG. The electrostatic latent image carrier is rotationally driven in the direction of the arrow at a predetermined speed (process speed). A brush roller constituted by a magnetic brush is brought into contact with the electrostatic latent image carrier with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion.

  As a magnetic brush as a contact charging member in this example, Zn—Cu ferrite particles having an average particle diameter of 25 μm and Zn—Cu ferrite particles having an average particle diameter of 10 μm are mixed at a weight ratio of 1: 0.05, Magnetic particles were used in which ferrite particles having an average particle diameter of 25 μm and having a peak at the position of each average particle diameter were coated with a medium resistance resin layer. The contact charging member is composed of the coated magnetic particles prepared above, a non-magnetic conductive sleeve for supporting the coated magnetic particles, and a magnet roll included therein, and the coated magnetic particles are formed on the sleeve with a thickness. Coating was performed at 1 mm to form a charging nip having a width of about 5 mm between the photosensitive member and the photosensitive member. The gap between the magnetic particle holding sleeve and the photosensitive member was about 500 μm. Further, the magnet roll is rotated so that the sleeve surface rubs in the opposite direction at twice as fast as the circumferential speed of the surface of the photoconductor, and the photoconductor and the magnetic brush are in uniform contact with each other. I did it.

Next, a specific example of the fixing process used in the method of the present invention will be described.
For fixing, roller fixing, belt fixing, surf fixing, IH fixing, or the like can be applied. Hereinafter, examples of roller fixing, belt fixing, surf fixing, and IH fixing will be described.
<Example of roller fixing>
An example of roller fixing will be described with reference to FIG.
The fixing unit includes a roller pair of a fixing roller 21 and a pressure roller 22. A heat-resistant release layer 24 is provided on each surface.

  Examples of the heat-resistant release layer 24 include silicon rubber (low temperature vulcanized silicon rubber, room temperature vulcanized silicon rubber, high temperature vulcanized silicon rubber, etc.), fluoro rubber, tetrafluoroethylene resin, tetrafluoroethylene, and hexafluoropropylene. Any one selected from a polymer resin, a tetrafluoroethylene / ethylene copolymer resin, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin, etc. is provided in a single-layer or multi-layer structure.

  The hardness of the rubber layer is 20 to 80 degrees (JIS K6301), more preferably 25 to 75 degrees, and the thickness of the rubber elastic body layer is 0.25 to 20 mm, more preferably 0.85 to 17 mm. These layers are provided on the outer peripheral surface of a metallic hollow roller core such as aluminum, stainless steel, iron or copper.

  The cleaning member 23 cleans minute toner deposits (minor offset), paper powder, foreign matter, and the like on the fixing roller 1. As the material, it is important to select a material whose release property is not better than that of the heat-resistant release layer 24. An example of such a material is felt.

The lamp 27 is for heating the fixing roller 21 or the pressure roller 22, and a roller surface temperature of the fixing roller 21 and the pressure roller 22 is controlled at a constant temperature by a thermistor (not shown). The separation claw 25 prevents the transfer paper 28 from being wound around the fixing roller 21, and is used to smoothly discharge the sheet.
The silicon oil application felt 26 impregnates the felt 26 with silicon oil 30. This oil application improves the releasability of the fixing roller 1. This oil application actively prevents toner from adhering to the roller.

  The toner 29 on the transfer paper 28 is satisfactorily fixed on the transfer paper 28 without causing an offset when passing through the roller pair of the fixing roller 21 and the pressure roller 22. If the toner component contains a release agent, it is not necessary to attach the coating felt 26 and the silicone oil 30, but if necessary, a felt impregnated with silicone oil may be added.

<Example of belt fixing>
An example of belt fixing is shown in FIG.
The belt 31 is sandwiched between the fixing roller 21 and the support roller 32. The fixing roller 21 forms a roller pair with the pressure roller 22. The pressure here is about 0.02 to 6 kg / cm ² , more preferably about 0.1 to 4 kg / cm ² . The surface of the support roller 32 is heated by the lamp 27 to supply heat to the belt 31. If necessary, a lamp 27 may be provided on the fixing roller 21 or the pressure 22.

The fixing roller 21 and the pressure roller 22 are provided with a heat-resistant release layer 24 on the outer peripheral surface of a metallic hollow roller core made of aluminum, stainless steel, iron, copper or the like.
The heat-resistant release layer 24 is made of silicon rubber (low temperature vulcanized silicon rubber, room temperature vulcanized silicon rubber, high temperature vulcanized silicon rubber, etc.), fluoro rubber, tetrafluoroethylene resin, tetrafluoroethylene / hexafluoropropylene copolymer resin. Arbitrarily selected from a tetrafluoroethylene / ethylene copolymer resin, a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin, and the like, a single-layer or multi-layer structure is provided. The hardness of the rubber layer is 20 to 80 degrees (JISK6301), more preferably 25 to 75 degrees. The layer thickness of the rubber elastic layer is 0.25 to 20 mm, more preferably 0.70 to 17 mm.

  The cleaning member 23 cleans fine offsets (toner deposits) on the surface of the fixing roller 21, paper dust, and other foreign matters. As the material, a material that is not as good as the heat release layer 24 is selected. A lamp 27 controls the temperature by a thermistor (not shown).

  The separation claw 25 prevents the transfer paper 28 from being wound around the fixing roller 21. The oil application member 26 is provided with a silicone oil impregnated felt, an oil supply roller, and applies oil to the object, supplies oil to the felt, and thereby provides the release property or assists by applying oil. is there.

  In the example of the film material, the belt 31 is preferably a heat resistant film having a thickness of 10 to 35 μm. For example, if necessary, a release layer to which a conductive material is added is coated to about 5 to 15 μm on polyester, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), polyimide, polyetherimide, or the like. Alternatively, it is made of a nickel belt having a heat-resistant delamination used for the fixing roller 21 described above or a release layer provided on a film material provided with a thickness of about 0.05 to 1 mm. The toner 29 on the transfer paper 28 is preheated and fixed by the roller pair of the fixing roller 21 and the pressure roller 22 in a melted state.

<Surf fixing>
As the fixing device, as shown in FIG. 7, a so-called surf fixing device that rotates and fixes a fixing film is also preferably used. More specifically, the fixing film 41 is an endless belt-like heat-resistant film, and is held by a driving roller 42, a driven roller 43, which is a supporting rotating body of the film, and a heater support provided below the rollers. It is stretched around a heating body 44 that is fixedly supported.

  The driven roller 43 also serves as a tension roller for the fixing film 41, and the fixing film 41 is rotated in the clockwise direction by the rotation of the driving roller 43 in the clockwise direction in the drawing. This rotational driving speed is adjusted to a speed at which the speeds of the transfer material 46 and the fixing film 41 become equal in the fixing nip region L where the pressure roller 45 and the fixing film 41 are in contact. Here, the pressure roller 45 is a roller having a rubber elastic layer having good releasability such as silicon rubber, and is in contact with the fixing nip region L with a total pressure of 4 to 10 kg while rotating counterclockwise. It is pressed with pressure.

  The fixing film 41 preferably has excellent heat resistance, releasability, and durability. A thin film having a total thickness of 100 μm or less, preferably 40 μm or less is used. For example, at least an image of a single layer film of a heat-resistant resin such as polyimide, polyetherimide, PES (polyether sulfide), PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin), or a composite layer film, for example, a 20 μm thick film The contact surface is coated with a release coating layer of PTFE (tetrafluoroethylene resin), PFA or other fluororesin added with a conductive material to a thickness of 10 μm, or an elastic layer such as fluororubber or silicon rubber. It is what.

In FIG. 7, the heating body 41 includes a flat substrate 47 and a fixing heater 48, and the flat substrate 47 is made of a material having high thermal conductivity and high electrical resistivity such as alumina and is in contact with the fixing film 41. A fixing heater 48 made of a resistance heating element is provided on the surface in the longitudinal direction. The fixing heater 48 is formed by applying an electric resistance material such as Ag / Pd or Ta ₂ N in a linear or belt shape by screen printing or the like. In addition, electrodes (not shown) are formed at both ends of the fixing heater 48, and the resistance heating element generates heat when energized between the electrodes. Further, a fixing temperature sensor 49 composed of a thermistor is provided on the surface of the substrate opposite to the surface provided with the fixing heater. The substrate temperature information detected by the fixing temperature sensor 49 is sent to a control unit (not shown), and the amount of electric power supplied to the fixing heater is controlled by the control unit, and the heating body 44 is controlled to a predetermined temperature.

<IH fixing>
FIG. 8 shows an example of another fixing device called an IH fixing device. In FIG. 8, the heating roller 61 heated by electromagnetic induction of the induction heating means 66, the fixing roller 62 arranged in parallel with the heating roller 61, and the heating roller 61 and the fixing roller 62 are stretched over and are heated. And an endless belt-like heat-resistant belt (toner heating medium) 63 that is heated by at least one of these rollers and rotates in the direction of arrow A, and is pressed against the fixing roller 62 via the belt 63 and also the belt 63 And a pressure roller 64 rotating in the forward direction.

  The heating roller 61 is made of, for example, a hollow cylindrical magnetic metal member such as iron, cobalt, nickel, or an alloy of these metals. The outer diameter is, for example, 30 mm, the thickness is, for example, 1 mm, and the temperature rises quickly with a low heat capacity. ing. The fixing roller 62 includes a metal core 62a made of, for example, stainless steel, and an elastic member 62b covered with a core metal 62a made of a heat-resistant silicone rubber in a solid or foamed form. In order to form a contact portion having a predetermined width between the pressure roller 64 and the fixing roller 62 by the pressing force from the pressure roller 64, the outer diameter is set to about 40 mm and larger than the heating roller 61. The elastic member 62b has a thickness of about 0.5 to 30 mm and a hardness of about 20 to 80 ° (JIS6301 hardness). With this configuration, the heat capacity of the heating roller 61 is smaller than the heat capacity of the fixing roller 62, so that the heating roller 61 is rapidly heated and the warm-up time is shortened.

  The belt 63 stretched between the heating roller 61 and the fixing roller 62 is heated at the contact portion W1 with the heating roller 61 heated by the induction heating means 66. The inner surface of the belt 63 is continuously heated by the rotation of the rollers 61 and 62, and as a result, the entire belt is heated.

  The thickness of the release layer attached to the belt surface is preferably about 5 μm to 50 μm, particularly about 20 μm. By doing so, the toner image T formed on the recording material 71 is sufficiently wrapped by the surface layer portion of the belt 63, so that the toner image T can be uniformly heated and melted. When the thickness of the release layer is smaller than 5 μm, the heat capacity of the belt 63 becomes small and the belt surface temperature rapidly decreases in the toner fixing process, so that the fixing performance cannot be sufficiently ensured. Further, when the thickness of the release layer is larger than 50 μm, the heat capacity of the belt 63 is increased and the time required for warm-up is increased. In addition, in the toner fixing process, the belt surface temperature is difficult to decrease, the agglomeration effect of the melted toner at the fixing portion outlet cannot be obtained, the belt releasability is reduced, and the toner adheres to the belt. Hot offset occurs.

In addition, as a base material of the belt 63, a heat-resistant resin layer such as a fluorine resin, a polyimide resin, a polyamide resin, a polyamideimide resin, a PEEK resin, a PES resin, or a PPS resin is used instead of the heat generating layer made of metal. May be.

  The pressure roller 64 includes, for example, a metal core 64b made of a metal member having high thermal conductivity such as copper or aluminum, and an elastic member having high heat resistance and toner releasability provided on the surface of the metal core 64b. 64a. In addition to the above metal, SUS may be used for the core metal 64b. The pressure roller 64 presses the fixing roller 62 via the belt 63 to form the fixing nip portion N. Here, the pressure roller 64 is hardened by making the pressure roller 64 harder than the fixing roller 62. The pressure roller 64 bites into the fixing roller 62 (and the belt 63), and this biting causes the recording material 71 to follow the circumferential shape of the surface of the pressure roller 64, so that the recording material 71 can be easily separated from the surface of the belt 63. Is given. The outer diameter of the pressure roller 64 is about 40 mm, the same as that of the fixing roller 62, but the wall thickness is about 0.3 to 20 mm, which is thinner than the fixing roller 62, and the hardness is about 10 to 70 ° (JIS6301 hardness). As described above, the fixing roller 62 is harder.

  As shown in FIGS. 8 and 9A and 9B, the induction heating unit 66 that heats the heating roller 61 by electromagnetic induction includes an excitation coil 67 that is a magnetic field generation unit, and the excitation coil 67 is wound. And a coil guide plate 68. The coil guide plate 68 has a semi-cylindrical shape arranged close to the outer peripheral surface of the heating roller 61. As shown in FIG. 9B, the excitation coil 67 is composed of a single long excitation coil wire. 68 is alternately wound in the axial direction of the heating roller 61. The excitation coil 67 is connected to a drive power supply (not shown) whose oscillation circuit has a variable frequency. Outside the excitation coil 67, a semi-cylindrical excitation coil core 69 made of a ferromagnetic material such as ferrite is fixed to the excitation coil core support member 70 and is disposed close to the excitation coil 67. Note that the normal excitation coil core 69 has a relative permeability of 2500.

  A high frequency alternating current of 10 kHz to 1 MHz, preferably a high frequency alternating current of 20 kHz to 800 kHz, is supplied to the exciting coil 67 from a driving power source, thereby generating an alternating magnetic field. The alternating magnetic field acts on the heating roller 61 and the heat generating layer 3a of the belt 63 in the contact area W1 between the heating roller 61 and the heat-resistant belt 63 and in the vicinity thereof, and the direction B prevents the change of the alternating magnetic field inside these. Eddy current I flows through This eddy current I generates Joule heat corresponding to the resistance of the heating roller 61 and the heat generating layer, and the belt 63 having the heating roller 61 and the heat generating layer mainly in the contact area between the heating roller 61 and the belt 63 and its vicinity. Induction heating. The belt 63 heated in this way is detected by a temperature detection means 65 comprising a thermosensitive element such as a thermistor disposed in contact with the inner surface side of the belt 63 in the vicinity of the entrance side of the fixing nip N. The belt inner surface temperature is detected.

<Alternate electric field development>
A developing device for applying an alternating electric field used in the method of the present invention will be described. In the developing device 80 shown in FIG. 10, during development, a vibration bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve 81 as a developing bias by the power source 82. The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing portion. In this alternating electric field, the developer toner and the carrier vibrate vigorously, and the toner flies off the electrostatic binding force on the developing sleeve 81 and the carrier and flies to the latent image carrier drum 84, so that the latent image carrier drum has a latent image. It adheres corresponding to the image.

  The difference (maximum peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 KV, and the frequency is preferably 1 to 10 KHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. This is preferable for preventing toner adhesion.

  When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the latent image carrier in one cycle of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the latent image carrier and the time average value of the bias can be increased, so that the movement of the toner is further activated and the toner is moved to the latent image surface. It is possible to improve the rough feeling and the resolution by adhering faithfully to the potential distribution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the latent image carrier can be reduced, the movement of the carrier is calmed down, The probability that the carrier adheres to the background portion can be greatly reduced.

Next, the structure of a preferable electrostatic latent image carrier (photoconductor) used in the image forming method of the present invention will be described.
<Configuration of photoconductor>
(About amorphous silicon photoconductor)
The electrostatic latent image carrier used in the present invention is preferably the following amorphous silicon photoreceptor. That is, the conductive support is heated to 50 ° C. to 400 ° C., and is deposited on the support by a film forming method such as a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, a photo CVD method, or a plasma CVD method. An amorphous silicon photoreceptor having a photoconductive layer made of a-Si (hereinafter referred to as “a-Si-based photoreceptor”). Among them, a plasma CVD method, that is, a method in which a source gas is decomposed by direct current, high frequency or microwave glow discharge to form an a-Si deposited film on a support is preferably used.

(About layer structure)
The layer structure of the amorphous silicon photoconductor is, for example, as follows. FIG. 11 is a schematic configuration diagram for explaining a layer configuration. In the electrophotographic photoreceptor 500 shown in FIG. 11A, a photoconductive layer 502 made of a-Si: H, X and having photoconductivity is provided on a support 501. An electrophotographic photoreceptor 500 shown in FIG. 11B includes a photoconductive layer 502 made of a-Si: H, X and having photoconductivity on a support 501, and an amorphous silicon-based surface layer 503. It is configured. An electrophotographic photoreceptor 500 shown in FIG. 11C has a photoconductive layer 502 made of a-Si: H, X and having photoconductivity on a support 501; an amorphous silicon surface layer 503; And an amorphous silicon based charge injection blocking layer 504. In the electrophotographic photoreceptor 500 shown in FIG. 11D, a photoconductive layer 502 is provided on a support 501. The photoconductive layer 502 includes a charge generation layer 505 made of a-Si: H, X and a charge transport layer 506, and an amorphous silicon-based surface layer 503 is provided thereon.

(About support)
The support for the photoreceptor may be conductive or electrically insulating. Examples of the conductive support include metals such as Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, and Fe, and alloys thereof such as stainless steel. Also, at least the surface on the side where the photosensitive layer is to be formed of an electrically insulating support such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene, polyamide or other synthetic resin film or sheet, glass or ceramic. A conductively treated support can also be used. The shape of the support can be a cylindrical or plate-like or endless belt with a smooth or uneven surface, and the thickness thereof is appropriately determined so that a desired photoreceptor for an image forming apparatus can be formed. When flexibility as a photoreceptor for an image forming apparatus is required, it can be made as thin as possible within a range where the function as a support can be sufficiently exhibited. However, the support is usually 10 μm or more from the viewpoint of production and handling, such as mechanical strength.

(About injection prevention layer)
In the amorphous silicon photoconductor that can be used in the present invention, a charge injection blocking layer that functions to block charge injection from the conductive support side is provided between the conductive support and the photoconductive layer as necessary. It is more effective to provide (FIG. 11C). That is, the charge injection blocking layer has a function of blocking charge injection from the support side to the photoconductive layer side when the photosensitive layer is subjected to a charging process with a certain polarity on its free surface. When charged, it has a so-called polarity dependency that does not exhibit such a function. In order to provide such a function, the charge injection blocking layer contains a relatively large number of atoms for controlling conductivity as compared with the photoconductive layer.
The layer thickness of the charge injection blocking layer is preferably from 0.1 to 5 μm, more preferably from 0.3 to 4 μm, and most preferably from 0.5 to 0.5 in view of obtaining desired electrophotographic characteristics and economic effects. It is desirable to be 3 μm.

(About photoconductive layer)
The photoconductive layer is formed on the undercoat layer as necessary, and the layer thickness of the photoconductive layer 502 is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects, preferably It is desirable that the thickness is 1 to 100 μm, more preferably 20 to 50 μm, and most preferably 23 to 45 μm.

(About charge transport layer)
The charge transport layer is a layer mainly having a function of transporting charges when the photoconductive layer is functionally separated. The charge transport layer includes at least silicon atoms, carbon atoms, and fluorine atoms as constituent elements, and is formed of a-SiC (H, F, O) including hydrogen atoms and oxygen atoms as required. Conductive properties, especially charge retention properties, charge generation properties, and charge transport properties. In the present invention, it is particularly preferable to contain an oxygen atom. The layer thickness of the charge transport layer is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects. The charge transport layer is preferably 5 to 50 μm, more preferably 10 to 40 μm, Optimally, the thickness is desirably 20 to 30 μm.

(About the charge generation layer)
The charge generation layer is a layer mainly having a function of generating charges when the photoconductive layer is functionally separated. This charge generation layer is composed of a-Si: H containing at least silicon atoms as components and substantially no carbon atoms and, if necessary, hydrogen atoms, and has desired photoconductive properties, particularly charge generation properties. , Has charge transport properties. The layer thickness of the charge generation layer is appropriately determined as desired from the viewpoints of obtaining desired electrophotographic characteristics and economic effects, etc., preferably 0.5 to 15 μm, more preferably 1 to 10 μm, optimally 1 ˜5 μm.

(About surface layer)
If necessary, the amorphous silicon photoconductor that can be used in the present invention can be provided with a surface layer on the photoconductive layer formed on the support as described above. It is preferable to form a surface layer. This surface layer has a free surface, and is provided to achieve the object of the present invention mainly in moisture resistance, continuous repeated use characteristics, electrical pressure resistance, use environment characteristics, and durability. The layer thickness of the surface layer in the present invention is usually 0.01 to 3 μm, preferably 0.05 to 2 μm, and most preferably 0.1 to 1 μm. If the layer thickness is less than 0.01 μm, the surface layer is lost due to wear or the like during use of the photoreceptor, and if it exceeds 3 μm, electrophotographic characteristics such as an increase in residual potential are observed.

Next, materials constituting the toner will be described.
<Colorant>
The colorant that can be used in the color image forming method of the present invention will be described.

(Black colorant)
Carbon black, spirit black, aniline black (CI PIGMENT BLACK 1)

(Colorant for yellow)
C. I. PIGMENT YELLOW 1
Symbol Fast Yellow GH-B (Dainippon Ink)
C. I. PIGMENT YELLOW 3
Symbol Fast Yellow 10GH (Dainippon Ink)
C. I. PIGMENT YELLOW 12
Lionol Yellow GRO (Toyo Ink)
Symbol Fast Yellow GF (Dainippon Ink)
C. I. PIGMENT YELLOW 13
Symbol Fast Yellow GRF (Dainippon Ink)
C. I. PIGMENT YELLOW 14
Symbol Fast Yellow 5GF (Dainippon Ink)
C. I. PIGMENT YELLOW 17
Symbol Fast Yellow 8GF (Dainippon Ink)
Lionol Yellow FGNT (Toyo Ink)
C. I. PIGMENT YELLOW 154
Chromofine Yellow 2080 (Daiichi Seika)
C. I. PIGMENT YELLOW 180
PV Fast Yellow HG (Clariant)

(Coloring agent for magenta)
C. I. PIGMENT RED 5
Symbol Fast Red 4188N (Dainippon Ink)
C. I. PIGMENT RED 22
Seikafast Scarlet G (Daiichi Seika)
Symbol Fast Scallet BG (Dainippon Ink)
C. I. PIGMENT RED 48: 1
Linol Red 2B FG-3303-G (Toyo Ink)
Simulator Red 3109 (Dainippon Ink)
C. I. PIGMENT RED 57: 1
Lionol Red 6B FG-4215 (Toyo Ink)
Symbler Brilliant Carmine 6B273 (Dainippon Ink)
PV Rubine L6B (Clariant)
C. I. PIGMENT RED 112
Oriental Fast Red GR (Toyo Ink)
C. I. PIGMENT RED 114
Pollux Pink PM-2B (Sumika Color)
C. I. PIGMENT RED 122
Hostaperm Pink E 02 (Clariant)
Fastogen Super Magenta R (Dainippon Ink)
C. I. PIGMENT RED 166
Fastogen Super Red R (Dainippon Ink)
C. I. PIGMENT RED 184
Permanent Rubin F6B (Clariant)

(Colorant for cyan)
C. I. PIGMENT BLUE 15: 3
Chroma fine Blue 4920 (Daiichi Seika)
Fastogen Blue FGF (Dainippon Ink)
Lionol Blue FG-7351 (Toyo Ink)
C. I. PIGMENT BLUE 16
Heliogen Blue 16 (BASF)
C. I. PIGMENT GREEN 7
Phthalocyanine Green (Toyo Ink)
C. I. PIGMENT GREEN 36
Cyanine Green 2 YL (Toyo Ink)
The amount of the colorant is suitably 0.1 to 50 parts by weight, more preferably 0.5 to 25 parts by weight with respect to 100 parts by weight of the binder resin.

<Charge control agent>
In the toner of the present invention, examples of charge control agents include nigrosine dyes, chromium-containing complexes, quaternary ammonium salts, and the like, which are properly used depending on the polarity of the toner particles. In the case of a color toner, a colorless or light-colored toner that does not affect the color tone of the toner is preferable. For example, a metal salt of a salicylic acid metal salt or a salicylic acid derivative and the metal is Cr, Al, Ni, Co, Fe, Ti, Mn, Si , Sn and Zn (for example, Bontron E84, manufactured by Orient). The amount of the charge control agent is 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the binder resin.

<Binder resin>
Examples of the binder resin are as follows.
(1) Example of polyester resin General formula (2) or (3) selected from the group consisting of a diol component represented by the following general formula (1), a divalent or higher polyvalent carboxylic acid, an anhydride thereof, and a lower alkyl ester thereof The polyester resin obtained by condensation polymerization with an acid component containing a divalent carboxylic acid or its anhydride, or an acid component containing trimellitic acid or its anhydride. Moreover, compounds such as phthalic acid, isophthalic acid, terephthalic acid maleic acid, fumaric acid and anhydrides thereof, and lower alkyl esters thereof can be used.

(In the formula, R ¹ is an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the average value of the sum is 2 to 16).

(In the formula, R ² and R ³ are saturated or unsaturated hydrocarbon groups having 4 to 20 carbon atoms.)
Examples of the compound represented by the general formula (2) or (3) include succinic acid derivatives such as n-dodecenyl succinic acid, n-dodecyl succinic acid, n-butyl succinic acid, iso-dodecenyl succinic acid, and iso-octyl succinic acid. can give. In particular, as a toner, the image fixing property at a low temperature is sufficient, and the color developability and gloss are also good.

  Examples of the diol represented by the general formula (1) include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyester (2) -2,2-bis. (4-hydroxylphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (16) -2,2-bis (4-hydroxyphenyl) propane, etc. It is done.

(2) Examples of polyol resins Various types of polyol resins can be used, and the following are particularly preferable as those used in the present invention.

  As a polyol resin, (1) an epoxy group, (2) an alkylene oxide adduct of dihydric phenol or glycidyl ether thereof, and (3) a compound having one active hydrogen that reacts with the epoxy group in the molecule, 4) It is preferable to use a polyol obtained by reacting a compound having two or more active hydrogens in the molecule that react with an epoxy group. Furthermore, (1) the epoxy group is particularly preferably at least two bisphenol A type epoxy resins having different number average molecular weights. This polyol resin imparts good image gloss and transparency, and has an anti-offset effect if it is roller-fixed.

  The epoxy resin used in the present invention is preferably obtained by binding bisphenol such as bisphenol A or bisphenol F and epichlorohydrin. Epoxy resins are at least two types of bisphenol A type epoxy resins having different number average molecular weights in order to obtain stable fixing characteristics, the number average molecular weight of the low molecular weight component is 360 to 2000, and the number average molecular weight of the high molecular weight component is It is preferable that it is 3000-10000. Furthermore, it is preferable that the low molecular weight component is 20 to 50 wt% and the high molecular weight component is 5 to 40 wt%.

  When there are too many low molecular weight components, or when the molecular weight is lower than 360, the gloss is too high or the storage stability is not good. In addition, when there are too many high molecular weight components, or when the molecular weight is higher than 10,000, there is a possibility that the image gloss is insufficient or the fixing property is deteriorated.

  Examples of the compound used in the present invention include the following as the alkylene oxide adduct of divalent phenol. Examples include reaction products of ethylene oxide, propylene oxide, butylene oxide, and mixtures thereof with bisphenols such as bisphenol A and bisphenol F. The obtained adduct may be used after glycidylation with epichlorohydrin or β-methylepichlorohydrin. In particular, glycidyl ether of an alkylene oxide adduct of bisphenol A represented by the following general formula (4) is preferable.

In the general formula (4), R is _{- (CH 2) 2 -,} - CH 2 CH (CH 3) -, and - _{(CH 2) 3} - is one of. N and m are the number of repeating units, each of which is 1 or more, and n + m = 2 to 6.
Moreover, it is preferable that 10-40 wt% of alkylene oxide adduct of dihydric phenol or its glycidyl ether is contained with respect to polyol resin. If the amount is small, problems such as an increase in curl occur, and if n + m is 7 or more, or if the amount is too large, there is a possibility of excessive glossiness and deterioration of storage stability.

  Examples of the compound having one active hydrogen in the molecule that reacts with the epoxy group used in the present invention include monohydric phenols, secondary amines, and carboxylic acids. That is, phenol, cresol, isopropylphenol, aminophenol, nonylphenol, dodecylphenol, xylene, p-cumylphenol, and the like. Secondary amines include diethylamine, dipropylamine, dibutylamine, N-methyl (ethyl) piperazine and the like. Moreover, propionic acid etc. are mention | raise | lifted as carboxylic acid.

  In order to obtain a polyol resin having an epoxy resin part and an alkylene oxide part in the main chain of the present invention, various raw materials can be combined. For example, it can be obtained by reacting an epoxy resin having a glycidyl group at both ends and an alkylene oxide adduct of a dihydric phenol having both glycidyl groups with a dihalide, diisocyanate, diamine, dithiol, polyhydric phenol, or dicarboxylic acid. Of these, the reaction with dihydric phenol is most preferable from the viewpoint of reaction stability. Moreover, it is also preferable to use polyhydric phenols and polyhydric carboxylic acids in combination with dihydric phenols as long as they do not gel.

  Here, the amount of polyphenols and polycarboxylic acids is 15% or less, preferably 10% or less, based on the total amount, tris (4-hydroxyphenyl) methane, 1- [α-methyl-α (4 -Hydroxyphenyl) ethyl] benzene. Examples of the polyvalent carboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, terephthalic acid, trimellitic acid, and trimellitic anhydride. Further, when these polyester resins and polyol resins have a high cross-linking density, it becomes difficult to obtain transparency and glossiness, and it is preferable to make them non-cross-linked or weakly cross-linked (THF insoluble content of 5% or less).

In the toner of the present invention, other resins may be used in combination for improving fluidity, filming on the latent image carrier, pulverization property, storage stability, charging property and the like.
For example, for example, polystyrene, poly-p-chlorostyrene, polyvinyltoluene and other styrene and its substituted homopolymers; styrene / p-chlorostyrene copolymer, styrene / propylene copolymer, styrene / vinyltoluene copolymer Polymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer, styrene / methacrylic Methyl acid copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / acrylonitrile copolymer, styrene / vinyl methyl ketone copolymer Coalescence, styrene / butadiene copolymer, Styrene copolymers such as tylene / isoprene copolymer and styrene / maleic acid copolymer; acrylic ester monopolymers such as polymethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polybutyl methacrylate And their copolymers; polyvinyl derivatives such as polyvinyl chloride and polyvinyl acetate; polyurethane polymers, polyamide polymers, polyimide polymers, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, etc. These may be used alone or in combination, but are not particularly limited thereto.

  As an example of the mold release agent, a solid or semi-solid organic material (ring and ball method softening point of about 50 to 160 ° C.) having a weight average molecular weight of 50000 or less is preferable. For example, animal waxes (beeswax, whale wax, wool wax) plant waxes (carnauba wax, candelilla wax, wood wax, rice wax, sugar cane wax) mineral waxes (montane wax, lignite wax) petroleum Wax (paraffin wax, microcrystalline wax, petrotam) Synthetic hydrocarbons (Fischer-Tropsch wax and derivatives, olefinic hydrocarbons and derivatives) Modified wax (Montan wax derivatives, paraffin wax derivatives, microcrystal wax derivatives) Hydrogenated wax (curing) Castor oil, hydrogenated rapeseed oil) Fatty acid amide (stearic acid amide, oleic acid amide) ketone, amine, imine, ester (monohydric alcohol fatty acid ester, polyhydric alcohol fatty acid ester) chlorination And the like hydrocarbons, alpha olefinic synthetic animal waxes.

  Examples of external additives as other additives include colloidal silica, hydrophobic silica, metal oxides (titanium oxide, tin oxide, antimony oxide, aluminum oxide, iron oxide, strontium titanate, barium titanate, etc.), Nitride (silicon nitride, titanium nitride, zirconium nitride) and carbide (silicon carbide, boron carbide, zirconium carbide) are also preferable. These particles having a hydrophobic group on the surface are particularly preferred, so that they were treated with a hydrophobizing treatment, a silane coupling agent, silicon oil, a titanium coupling agent, etc. as necessary from the viewpoint of improving fluidity and frictional charging stability. It may be a thing.

  As a method for treating the surface, for example, the material to be treated is dissolved in a solvent, and the external additive is dispersed in the solution. Thereafter, the solvent is removed by filtration or spray-drying, and after curing by heating, or the material to be processed is dissolved in the solvent by a fluidized bed apparatus, and sprayed onto the external additive to be processed and then heated. Drying is performed to remove the solvent, and the film is cured and then crushed. The particle diameter (primary particle diameter) of the external additive (additive) is preferably 0.005 to 4 μm, more preferably 0.01 to 2 μm. These particles may be treated with a hydrophobizing treatment, a silane coupling agent, silicon oil or the like as necessary from the viewpoint of improving fluidity and frictional charging stability.

  Further, a plurality of types of external additives may be added. For example, when a toner having a different particle size is added and a toner image is transferred to the final transfer member (paper), the toner is not excessively pressed by the transfer roller or the like due to the spacer effect by the external additive having a large particle size. Therefore, the character image does not become a hollow image. Further, polymer fine particles such as polystyrene, polymethyl methacrylate, and polyvinylidene fluoride, and those obtained by subjecting these fine particles to a hydrophobic treatment and a charge adjustment treatment may be added.

  The external additive is mixed with the toner in a manner that does not cause pulverization. For example, a horizontal cylindrical mixer, a V-type mixer, a double cone mixer, a high-speed fluid mixer, a conical screw mixer, a rotating disk mixer, or the like is used. By adding an additive to the toner, for example, the fluidity of the toner is improved. Also, the toner charge amount can be arbitrarily controlled by adjusting the type and amount of the additive. For this reason, the flowability of the developer is also improved.

  In the present invention, it is preferable that the toner for making particles irregular in shape is a yellow toner that is monochromatic and has a low resolution, or a black toner that has a high degree of copying a black document even in a color image forming apparatus. Bring. In addition, when all of the toners are irregular, the blade cleaning is good, but the sharpness and halftone reproduction are not good. Further, if the irregular toner particle size is made larger than that of the other toners, the toner can be prevented from slipping by the toner at the tip of the blade, so that the cleaning property is further improved.

  The toner used in the present invention can be produced by various known methods or a combination thereof. For example, in the kneading and pulverization method, a binder resin and a coloring agent, which are required, are dry-mixed, heated and melt-kneaded with an extruder, two rolls, three rolls, etc., and cooled to solidify.

  The cooled and solidified particles are crushed by colliding and crushing particles with each other by airflow disturbance in a supersonic nozzle that generates airflow, and colliding a solid / gas mixture with a collision plate (ceramic) installed in front of the nozzle. I do. As a result, the raw material powder (toner particles) directly collides with the collision plate and gives a large collision force to the particles, so that the particle shape becomes indefinite. Specifically, it is pulverized by a supersonic jet mill pulverizer (I type, I2 type mill, etc.). If necessary, the toner is classified by a classifier.

  It has been described above that the shape of such a toner is an irregular shape with corners. Therefore, by applying hot air or mechanical energy to the pulverized / classified toner, the toner surface is rounded and approaches the spherical toner as much as possible from the irregular shape. In such a shape, the fluidity of the toner particles is improved.

  In addition, toner particles that are almost as spherical as the toner obtained by the polymerization method can be obtained. For example, a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization, or the like can be used. In particular, since the polymerized toner has a spherical shape, the fluidity of the toner particles and the transferability of the toner particles are good. In addition, a sharp particle size distribution is obtained, and the resolution of the image is particularly good.

The shape of the toner particles was evaluated as follows.
The equivalent circle diameter and the number distribution can be measured using a flow type particle image analyzer FPIA-1000 manufactured by Sysmex Corporation. An outline of the apparatus and measurement is described in JP-A-8-136439. The measurement was adjusted to a 1% NaCl aqueous solution using primary sodium chloride and then passed through a 0.45 μm filter to 50 to 100 ml of a surfactant, preferably 0.1 to 5 ml of an alkylbenzene sulfonate as a dispersant. In addition, add 1-10 mg of sample. This was subjected to dispersion treatment for 1 minute with an ultrasonic disperser (output 35 W, frequency 50 kHz), and measurement was performed using a dispersion liquid in which the particle concentration was adjusted to 5000 to 15000 particles / μl.

  For the measurement of the number of particles, a two-dimensional image area captured by a CCD camera and a diameter of a circle having the same area are calculated as an equivalent circle diameter. From the accuracy of CCD pixels, an effective circle diameter of 0.6 μm or more was determined to obtain the number of particles.

  The circularity indicates the degree of sphericalness (roundness) of the toner particles. The closer the value is to 1, the more spherical the particle becomes, and the more the value becomes 1, the more gradually becomes indefinite. When this value is 0.94 or more, the shape of the toner is almost spherical. On the other hand, when it becomes less than 0.94, it slightly deviates from the spherical shape and changes into the shape of irregularly shaped toner particles. A toner having a roundness of about 0.85 is a toner having an uneven shape by being pulverized by a collision pulverizer using jet air.

  Further, toner having a roundness of 0.89 to 0.99 is obtained by crushing with a collision pulverizer using jet air and having a concavo-convex shape. The toner is processed with heat to change the temperature to produce a toner having a circularity of 0.89 to 0.99. Specifically, the toner is put into a hot air spheronizer, and the hot air temperature is adjusted in the range of 120 to 480 ° C.

  The particle size of the toner of the present invention is preferably 3 to 10 μm, and if it exceeds 10 μm, it is difficult to obtain a smooth gradation, and the resolution is also lowered. In addition, the triboelectric charge (Q / M) of the toner particles by stirring in the developing unit is unlikely to rise quickly. On the other hand, if it is less than 3 μm, the rise of Q / M is good, but the tendency of toner scattering and contamination of the carrier surface becomes remarkable.

  The toner particle size is measured by using a 100 μm aperture (pore) by connecting an interface for outputting the number distribution and volume distribution by COULTER COUNTER MODEL TAII type (manufactured by Coulter). First, a toner measurement sample is dispersed in a surfactant added to an electrolytic aqueous solution. The sample is injected into another 1% NaCl electrolyte, and an electric current is passed between the electrodes through the electrolyte having electrodes on both sides of the aperture tube. From this resistance change, the particle size of 2 to 40 μm is obtained. The distribution is measured, and the volume average particle diameter is obtained from the volume average distribution.

  In the present invention, the toner particle size distribution is important as well as the toner particle size. The number of toner particles having a particle diameter of 5 μm or less is desirably 60% by number or less. If it is more than this, the toner tends to adhere to the surface of the toner conveying member or toner layer regulating member of the carrier particles of the two-component developer, and the toner to be replenished is not efficiently charged, so that the toner scatters into the machine. , Dirt on the image area is likely to occur.

  In addition, toner particles are likely to aggregate, and it is difficult to obtain a smooth image, and voids occur in the character portion. In addition, the toner tends to harden during storage. Further, it is desirable that the toner particles having a particle diameter of 16 μm or more is 2% by volume or less. If it is more than this, the reduction in resolution and the roughness of the image become remarkable. Further, the developed toner is not easily transferred onto the transfer paper, and voids are likely to occur in the character portion.

  The toner of the present invention is used by mixing with carrier particles used as a two-component developer. The carrier particle size is 25 to 65 μm, more preferably 35 to 60 μm. If it exceeds 65 μm, the solid uniformity is poor, and a carrier scratch occurs in the solid portion. Also, when a picture document is copied, an edge effect occurs at the leading edge of the image (relative to the paper discharge direction). Degradation of image quality such as poor dot reproducibility and poor roughness is observed. On the other hand, if it is less than 25 μm, it is easy to granulate at the time of forming the coating layer, and a large amount of clump-like carriers are formed, causing troubles during production. In addition, carrier scattering from the developing sleeve and carrier adhesion to the image area become significant.

  Carriers used in the present invention include iron oxide powder, Ni—Zn ferrite, Cu—Zn ferrite, Ba ferrite, Sr ferrite, Zn—Fe ferrite, Mn—Zn—Fe ferrite, Mn—Mg—Fe ferrite, Ca -Mn-Fe ferrite, Ca-Mg-Fe ferrite, Li-Fe ferrite, magnetite, glass beads, iron powder, Ni powder, Co powder, resin beads and the like having a particle diameter of 30 to 60 μm are used.

  In the carrier particle size distribution, when the amount of coarse powder of 250 mesh or more is 20% or more, the feeling of roughness of the image becomes remarkable. Also, the resolution of the image is not good. Further, since the replenished toner is not easily charged with the carrier promptly, background stains occur. When the amount of fine powder of 350 mesh is 25% or more, the occurrence of carrier adhesion increases. In addition, the flowability of the developer is deteriorated, and development cannot be performed smoothly.

  The carrier used in the present invention may be a coated carrier. The release resin for carrier coating in this case includes polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, and chlorosulfonated polyethylene; polyvinyl and polyvinylidene resins such as polystyrene and acrylic resins (such as polymethyl methacrylate). ), Polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight comprising an organosiloxane bond Silicone resins such as silicone resins or modified products thereof (for example, modified products using alkyd resin, polyester, epoxy resin, polyurethane, etc.) Fluoropolymers such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc .; polyamides; polyesters such as polyethylene terephthalate; polyurethanes; polycarbonates; amino resins such as Urea-formaldehyde resin; epoxy resin and the like.

  Among these, acrylic resin, silicone resin or a modified product thereof, and fluorine resin, particularly silicone resin or a modified product thereof are preferable from the viewpoint of preventing adhesion of spent toner to the carrier. The silicone resin here may be any conventionally known silicone resin, straight silicone consisting only of an organosiloxane bond represented by the following formula, and a silicone resin modified with alkoxide, polyester, epoxy, urethane or the like. Etc.

(In the above formula, R1 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or a phenyl group, R2 and R3 are hydrogen groups, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, a phenoxy group, and 2 to 4 carbon atoms. Alkenyl group, alkenyloxy group having 2 to 4 carbon atoms, hydroxy group, carboxyl group, ethylene oxide group, glycidyl group or the following formula

R4 and R5 are a hydroxyl group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, and the number of carbon atoms. 2 to 4 alkenyloxy groups, phenyl groups, phenoxy groups, k, l, m, n, o and p each represent an integer of 1 or more. )

Each of the above substituents may have a substituent such as an amino group, a hydroxyl group, a carboxyl group, a mercapto group, an alkyl group, a phenyl group, an ethylene oxide group, a glycidyl group, or a halogen atom in addition to an unsubstituted one. .
The amount of the releasable resin as described above is suitably about 0.5 to 50 parts by weight per 100 parts by weight of the carrier core material.

  As a method for forming the resin layer, the resin may be applied to the surface of the carrier core particle by means of a spraying method, a dipping method, or the like, as in the past. Examples include tilting pan by rolling, drum, fluidized bed, movable spray, fluidized bed by aeration (spray drying, vibration, draft pipe, movable draft pipe), spouted bed (jet fluidized bed), rolling fluidized bed (with slits) The carrier core material is coated with resin by a rotating disk) or by stirring and mixing (stirring blade, high-speed shearing, vertical stirring blade, eccentric stirring blade).

  Furthermore, the coated carrier used in the present invention may be one in which a conductive material is dispersed in the coating layer in order to adjust carrier resistance. Specific examples of the conductive material in this case include the following.

(A) White conductive material ETC-52 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd. KV400 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd. ECR-72 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd. ECTR-82 (TiO ₂ system) titanium Industrial 500W (TiO ₂ series) Ishihara Sangyo 300W (TiO ₂ series) Ishihara Sangyo S-1 (TiO ₂ series) Ishihara Sangyo W-1 (SnO ₂ series) Mitsubishi Metal 23K (ZnO) ) Conductive zinc white no. 1 (ZnO) Honjo Chemical Co., Ltd., conductive zinc white 2 (ZnO) Honjo Chemical Co., Ltd. W-10 (TiO ₂ series) Mitsubishi Metals Corporation Dentor WK-100 (conductive fiber) Otsuka Chemical Co., Ltd. Dentor WK-200 (conductive fiber) Otsuka Chemical Co., Ltd. Dentor WK-300 (conductive fiber) manufactured by Otsuka Chemical Co. MEC300 (SnO ₂ system) Teikoku Kako Co. MEC500 (SnO ₂ system) Teikoku Kako Co.

(B) Carbon Black Pearls 2000, VULCANXC-72 (manufactured by Cabot) Ketjen black EC / DJ500, Ketjen black EC / DJ600 (manufactured by Lion Akzo) Denka black powder, Denka black powder (manufactured by Denki Kagaku Kogyo) CONDUCTEX SC (manufactured by Columbia Carbon Co.)

  A coupling agent may be added. The addition of a coupling agent improves the adhesion between the carrier core material and the coating layer, and the layer does not peel off even when the developing part is stirred. In addition, the charge amount can be adjusted. For example, the charge amount is hardly generated under the influence of moisture under high temperature and high humidity conditions, but a good charge amount can be secured by adding a coupling agent.

  Examples of silane coupling agents include trade names: SH6020 (γ- (2-aminoethyl) aminopropyltrimethoxysilane), SZ6023 (γ- (2-aminoethyl) aminopropylmethyldimethoxysilane), SH6026 (aminosilane), SZ6030 (γ-methacryloxypropyltrimethoxysilane), SZ6032 (N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, hydrochloride), SZ6050 (aminosilane), SZ6040 (γ-glycid) Xipropyltrimethoxysilane), SH6062 (γ-mercaptopropyltrimethoxysilane), SZ6070 (methyltrimethoxysilane), SZ6072 (methyltriethoxysilane), SZ6075 (vinyltriacetoxysilane), SZ 076 (γ-chloropropyltrimethoxysilane), SZ6079 (hexamethyldisilazane), SZ6083 (γ-anilinopro X24 (trimethylchlorosilane) and the like are manufactured by Toray Dow Corning Silicone Co., Ltd., KA1003 (vinylchlorosilane), KBC1003 ( Vinyltris (β-methoxyethoxy) silane), KBM1003 (vinyltrimethoxysilane), KBE1003 (vinyltriethoxysilane), KBM503 (γ-methacryloxypropyltrimethoxysilane), KBM303 (β- (3,4 epoxy cyclohexyl) ethyltri Methoxysilane), KBM403 (γ-glycidoxypropyltrimethoxysilane), KBM402 (γ-glycidoxypropylmethylethoxysilane), KBM603 (N-β (amino) Til) γ-aminopropyltrimethoxysilane), KBM602 (N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane), KBM903 (γ-aminopropyltriethoxysilane), KBM803 (γ-mercaptopropyltrimethoxysilane) , KBM573 (N-phenyl-γ-aminopropyltrimethoxysilane), KBM703 (γ-chloropropyltrimethoxysilane), etc. manufactured by Shin-Etsu Chemical Co., Ltd., and also using an aluminum coupling agent and a titanium coupling agent Also good.

Furthermore, an example as a fluorine resin is added.
Fluorine-containing monomers used for carrier coating layer formation include vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinyl ether substituted with fluorine atoms, and vinyl ketone substituted with fluorine atoms. As the polymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, perfluoroalkyl vinyl ether-vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride Polymers, tetrafluoroethylene copolymers, polymers containing vinyl ethers substituted with fluorine atoms, polymers containing vinyl ketones substituted with fluorine atoms, fluorinated polymers There is Kill acrylate polymer or fluorinated alkyl methacrylate polymer.

  Components copolymerized with the fluorine-containing monomer include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, and benzyl acrylate. Benzyl methacrylate, acrylic acid amide, methacrylic acid amide, cyclohexyl acrylate, cyclohexyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, ethylene, propylene, and the like.

  The polymer and copolymer can be used alone as a coating material, but may contain other resin components. Other resin components include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, benzyl acrylate, benzyl methacrylate, acrylic acid Polymerized from amide, methacrylic amide, cyclohexyl acrylate, cyclohexyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, or any kind or more of monomers There are copolymers.

  The amount of the conductive substance and the coupling agent is 0.05 to 70 parts by weight, more preferably 0.1 to 50 parts by weight with respect to 100 parts by weight of the silicone resin.

  In addition, the present invention comprises a carrier particle having a spherical particle and an uneven portion formed by a discontinuous phase in which the surface state is melted. A resin coating layer is provided on the surface, and the uneven portion on the surface of the spherical particle after coating is discriminated. The thing which consists of what has the coating layer which can do may be used. Therefore, even if the surface of the core material is a convex portion, a coating layer is present, carrier resistance is appropriately maintained, and a carrier having a long life (high durability) can be provided by suppressing spent. In other words, a uniform coating layer is provided along the circumferential shape of the core material, and the convex portion is thinner than the concave portion. On the other hand, the concave portion has a thick coating layer.

  With such a configuration, the presence of uneven portions moderately suppresses an increase in carrier resistance, and the presence of concave portions and convex portions maintains a good charge rising property with the toner, and the spent. -Does not cause toner adhesion.

  If even a part of the convex part is exposed, toner adheres to the carrier in that part, leading to a decrease in charge amount and toner scattering. In addition, if a coating layer is provided like a shell without aligning with the circumferential shape of the surface of the core material (the yolk is the core material in the image of an egg), there is no adhesion of spent or toner, and the coating layer becomes thicker, so There is no problem even if the coating layer is somewhat scraped during use.

  However, there is no problem with line copy due to edge effects such as increased carrier resistance, increased charge amount, decreased image density, or edge effect. Prominent in copying.

  The present invention provides a carrier that moderately suppresses an increase in carrier resistance particularly due to the presence of convex portions, maintains good chargeability with toner due to the presence balance of concave portions, and has a long life (high durability). In particular, a two-component developer combining a toner and a carrier in such a carrier has a uniform charge amount distribution and poor charging, background staining, toner scattering, insufficient image density, unevenness of solid portions in an image, poor cleaning, etc. Eliminate.

Next, the resistance of carrier particles will be described.
The volume resistivity of the carrier particles is preferably 10 ⁸ to 10 ¹⁴ Ω · cm. If it exceeds 10 ¹⁴ Ω · cm, the edge effect is large and the roughness is large. There is no particular problem with character copying. However, with color copying, the above problem occurs when a picture is copied. In addition, the edges of the carrier become hard during development, and stripes and unevenness are likely to occur. If it is less than 10 ⁸ Ω · cm, carrier adhesion tends to occur, and if a small scratch occurs on the latent image carrier, the latent image is disturbed and the image quality is lowered.

The specific resistance is measured as follows. A sample was allowed to flow into a cell formed by two electrode plates having an area of 10 cm ² (length 4 cm, width 2.5 cm) facing each other at intervals of 2 mm, and in this state, a height of 15 mm The tapping operation of dropping from the position onto the flat plate is repeated 30 times to fill the cell with the sample. Next, after removing an excessive sample on the cell, a specific resistance is obtained by applying a voltage corresponding to a DC electric field of 500 V / cm to the electrode plate in an environment of 20 ° C. and 60% RH. The particle size distribution of the carrier is measured by a known apparatus utilizing the fact that the angular distribution of the forward diffracted light intensity of the laser beam by the particles is a function of the particle size.

In this two-component developing device, the development layer thickness is preferably limited to about 105 to 975 μm, and development is preferably performed by applying a direct current and / or alternating current bias voltage between the latent image carrier and the development sleeve. In particular, a high-density image can be obtained by reciprocating the toner according to the bias due to the AC bias. In the non-image area, the toner reciprocates according to the bias, so that a high-quality image free from background stain can be obtained.
(Process cartridge)
FIG. 12 shows a schematic configuration of a process cartridge used in an image forming apparatus for carrying out the color image forming method of the present invention.
In FIG. 12, 91 denotes the entire process cartridge, 92 denotes a photosensitive member, 93 denotes charging means, 94 denotes developing means, and 95 denotes cleaning means.
In the present invention, a plurality of components such as the photosensitive member 92, the charging unit 93, the developing unit 94, and the cleaning unit 95 are integrally combined as a process cartridge, and this process is performed. The cartridge is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.
(Description of image forming apparatus)
In the image forming apparatus having the process cartridge of the present invention, the photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the charging unit, and then image exposure light from an image exposing unit such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image is sequentially formed on the circumferential surface of the photosensitive member, and the formed electrostatic latent image is then toner developed by the developing means, and the developed toner image is exposed from the paper feeding unit. The transfer unit sequentially transfers the image to the transfer material fed in synchronization with the rotation of the photosensitive member between the transfer unit and the transfer unit. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor after the image transfer is cleaned by removing the transfer residual toner by a cleaning means, and after being further neutralized, it is repeatedly used for image formation.

Examples of the present invention and comparative examples are shown below. “Parts” in the following description is “parts by weight”.
A color toner was obtained by the following toner formulation.
[Binder resin] Polyester resin (Propylene oxide adduct of bisphenol A, polyester synthesized from terephthalic acid and succinic acid derivative): 100 parts [Charge control agent] Zinc salicylate (Bontron E84, Orient Chemical) 2 parts [Colorant ]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant)):
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink)):
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

  The toners of the respective colors were preliminarily kneaded with a mixer and then melt kneaded with a three roll mill at each prescribed amount. Next, the kneaded product was cooled, coarsely pulverized to about 0.5 to 3 mm, and then pulverized with an IDS2 type jet pulverizer. Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07.

  Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner.

On the other hand, as a carrier, a copolymer having a weight ratio of 75/25 to a copolymer of 2hydroxyethyl metal acrylate / methyl methacrylate / styrene and a copolymer of vinylidene fluoride / tetrafluoroethylene is used. A coated carrier obtained by coating 0.75% by weight (based on the core material) on a 50 μ ferrite core material was used.
A developer was prepared by weighing so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g.

  A black developer is set in the developing section A of the apparatus shown in FIG. 1, a yellow developer is set in the developing section B, a magenta developer is set in the developing section C, and a cyan developer is set in the developing section D. A scorotron charger was disposed in the charging process, a urethane blade cleaning section was disposed in the cleaning process, and the roller fixing section in FIG. 4 was disposed in the fixing process.

  Then, after the power is turned on, only the first image forming unit develops the solid image until the roller temperature of the fixing unit reaches a constant temperature. At that time, the toner is transferred without transferring the transfer paper (without passing the paper), and the solid image is transferred onto the conveyance belt. The toner image on the belt is passed through the second, third, and fourth image forming portions. Thereafter, the transport belt is added with an operation for performing a process of cleaning in the cleaning unit. A continuous test was performed at a speed of copying 28 sheets per minute after the temperature of the fixing portion reached a constant temperature, and the cleaning performance after 100,000 sheets was good.

[Comparative Example 1]
In Example 1, the black toner also modified the toner particle surface by passing the toner particles through hot air. When observed with an electron microscope, the toner particles were clearly rounded and rounded. The circularity of the toner particles was 0.96. A developer was prepared with this black toner in the same manner as in Example 1, and set in the developing section A. In addition, yellow, magenta, and cyan toner developers were used in Example 1, and each color developer was set in the same position as in Example 1 and tested in the same manner as in Example 1. There was a poor cleaning and the cleaning performance was not very good.

[Comparative Example 2]
In Example 1, the yellow, magenta, and cyan toner particles are not treated with hot air. The circularity of each toner particle was 0.79. Using each color toner and the black toner of Example 1, a developer was prepared in the same manner as in Example 1. The developing portions for each color were set in the same manner as in Example 1. When tested in the same manner as in Example 1, no defective cleaning occurred in the initial copy paper. However, since the character portion was slightly unclear, the toner filling was not sharp and the resolution was not good when observed with a magnifying glass. Also, the gradation of the halftone was not good, and the image was noticeably rough.

A color toner was obtained by the following toner formulation.
[Binder resin] Polyester resin (Propylene oxide adduct of bisphenol A, polyester synthesized from terephthalic acid and succinic acid derivative): 100 parts [Charge control agent] Zinc salicylate (Bontron E84, Orient Chemical) 2 parts [Colorant ]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant)):
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink)):
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

  Each color toner was preliminarily kneaded with a mixer and then melt kneaded with a three-roll mill at each prescribed amount. Next, the kneaded product was cooled, coarsely pulverized to 0.5 to 3 mm, and then pulverized by an IDS2 type jet pulverizer. Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07. Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner.

On the other hand, the carrier was produced as follows.
First, a coating solution was prepared according to the following formulation.

Silicone resin SR2411 (Toray Dow Corning) 300 parts Toluene 1200 parts

Next, the coating liquid was put in a rotating disk type fluidized bed coating apparatus together with 5 kg of ferrite carrier having an average particle diameter of 50 μm to coat the carrier. Thereafter, the coating was taken out from the apparatus and heated at 250 ° C. for 2 hours to age the film. In order to test by setting in a copying machine, a developer was prepared by weighing so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g. Each color developer was set at the same position as in Example 1 and tested in the same manner as in Example 1. As a result, the same result as in Example 1 was obtained.

  In Example 2, except that the charging step was changed from the scorotron charger to the roller charger shown in FIG. 2, the same configuration as in Example 2 was tested in the same manner as in Example 2, and the same result as in Example 2 was obtained.

  In Example 2, the charging process was changed from the scorotron charger to the roller charger of FIG. Further, the same results as in Example 2 were obtained when tested in the same manner as in Example 2 except that the fixing unit was replaced with the belt fixing in FIGS.

  In Example 4, a polyol resin synthesized from polyester with a low molecular weight bisphenol A type epoxy, a high molecular weight bisphenol A type epoxy, a glycidylated product of a bisphenol A type ethylene oxide adduct, bisphenol F, and P-cumylphenol. The same results as in Example 4 were obtained when tested in the same manner as in Example 4 with the same configuration as in Example 4 except for the above.

A color toner was obtained by the following toner formulation.
[Binder Resin] Polyol resin synthesized from low molecular weight bisphenol A type epoxy, high molecular weight bisphenol A type epoxy, glycidylated product of bisphenol A type ethylene oxide adduct, bisphenol F, P-cumylphenol 100 parts [charge control agent ] Zinc salicylate (Bontron E84, Orient Chemical) 2 parts [Release agent] Carnauba wax 3.5 parts [Colorant]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant))
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink))
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

Each color toner was preliminarily kneaded with a mixer and then melt kneaded with a three-roll mill at each prescribed amount. This grinding is performed in the same manner as in Example 1.
Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07. Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner. And when it tested similarly to Example 5, the same result as Example 5 was obtained.

A color toner was obtained by the following toner formulation.
[Binder Resin] Polyester resin (Propylene oxide adduct of bisphenol A, polyester synthesized from terephthalic acid and succinic acid derivative): 100 parts [Release agent] Carnauba wax: 3.5 parts [Charge control agent] Zinc salicylate Salt (Bontron E84, Orient Chemical) 2 parts [Colorant]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant))
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink))
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

The toners of the respective colors were preliminarily kneaded with a mixer and then melt kneaded with a three roll mill at each prescribed amount. This pulverization was performed in the same manner as in Example 1.
Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07. Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner. And when it tested similarly to Example 5, the same result as Example 5 was obtained.

  In Example 3, the constitution of the toner was as shown in Table 1 below.

Among the toner particles, black, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the black, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated yellow toner particles. The circularity of the yellow toner particles was 0.88, and the circularity of the magenta, cyan and black toner particles was 0.97.
This developer was set with a yellow developer in the developing section A of the apparatus shown in FIG. 4, a magenta developer in the developing section B, a cyan developer in the developing section C, and a black developer in the developing section D. And when it tested similarly to Example 5, the same result as Example 5 was obtained.

A polymerized toner was prepared as follows.
<Production example of black toner>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Colorant: 7.5 parts of carbon black
(Carbon black # 44, manufactured by Mitsubishi Chemical Corporation)

The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner.
On the other hand, a carrier was prepared by using the carrier of Example 2 so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g.

<Example of yellow toner>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))

  The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner. On the other hand, the carrier of Example 2 was used as a carrier, and a developer was prepared by weighing the total amount of the toner and the carrier to 1000 g so that the toner concentration was 5%.

<Magenta toner production example>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant))

  The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner. On the other hand, a carrier was prepared by using the carrier of Example 2 so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g.

<Example of cyan toner production>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Cyan colorant: C.I. I. Pigment Blue 15: 3 2.5 parts
(Lionol Blue FG-7351 (Toyo Ink))

The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner. On the other hand, the carrier of Example 2 was used as a carrier, and a developer was prepared by weighing the total amount of the toner and the carrier to 1000 g so that the toner concentration was 5%.
The configuration of the toner set in FIG. 1 is as shown in Table 2 below.

  And when it tested like Example 4, the same result as Example 4 was obtained.

  In Example 9, the configuration of the toner set in FIG. 1 is as shown in Table 3 below.

  And when it tested like Example 4, the same result as Example 4 was obtained.

  In Example 1, the developer in the developing unit A was set in the developing unit D. In addition, the developer in the developing section D was set in the developing section A, and the two developers were replaced and set. Then, after the power is turned on, only the fourth image forming unit develops the solid image until the roller temperature of the fixing unit reaches a constant temperature. At that time, transfer of toner does not supply transfer paper (does not pass paper), transfers a solid image onto the conveyance belt, and does not perform conveyance belt cleaning after solid development in the fourth image forming unit. Do not clean the belt. The toner image on the belt is passed through the first, second, third and fourth image forming portions. Thereafter, the transport belt is cleaned by a cleaning unit. When a continuous test was performed at a speed of copying 28 sheets per minute after the roller temperature of the fixing unit reached a constant temperature, the cleaning performance after 100,000 sheets was good.

A color toner was obtained by the following toner formulation.
[Binder resin] Polyester resin (Propylene oxide adduct of bisphenol A, polyester synthesized from terephthalic acid and succinic acid derivative): 100 parts [Charge control agent] Zinc salicylate (Bontron E84, Orient Chemical) 2 parts [Colorant ]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant)):
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink)):
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

  The toners of the respective colors were preliminarily kneaded with a mixer and then melt kneaded with a three roll mill at each prescribed amount. Next, the kneaded product was cooled, coarsely pulverized to about 0.5 to 3 mm, and then pulverized with an IDS2 type jet pulverizer. Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07.

  Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner.

On the other hand, as a carrier, a copolymer having a weight ratio of 75/25 to a copolymer of 2hydroxyethyl metal acrylate / methyl methacrylate / styrene and a copolymer of vinylidene fluoride / tetrafluoroethylene is used. A coated carrier obtained by coating 0.75% by weight (based on the core material) on a 50 μ ferrite core material was used.
A developer was prepared by weighing so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g.

A black developer is set in the developing section A of the apparatus shown in FIG. 2, a yellow developer is set in the developing section B, a magenta developer is set in the developing section C, and a cyan developer is set in the developing section D. A scorotron charger was disposed in the charging process, a urethane blade cleaning section was disposed in the cleaning process, and the roller fixing section in FIG. 5 was disposed in the fixing process.
Then, after the power is turned on to the machine, the solid image is developed only by the first image forming unit until the roller temperature of the fixing unit reaches a constant temperature. This solid image is transferred onto the intermediate transfer member. The toner image on the intermediate transfer member passes through the second, third, and fourth image forming portions. Thereafter, the operation of cleaning the toner on the intermediate transfer member by the cleaning unit is performed 10 times. A continuous test was performed at a speed of copying 28 sheets per minute after the temperature of the fixing portion reached a constant temperature, and the cleaning performance after 100,000 sheets was good.

[Modified Example of Example 12]
In Example 12, the same process as Example 12 is performed until the developer is set. In the evaluation, after the power is turned on, the solid image is developed only by the first image forming unit until the roller temperature of the fixing unit reaches a constant temperature. This solid image is transferred onto the intermediate transfer member. The toner image on the intermediate transfer member passes through the second, third, and fourth image forming portions. Thereafter, the solid image on the intermediate transfer member is not cleaned by the cleaning unit. The solid on the intermediate transfer member performs the operation of passing the first image forming unit and the second, third, and fourth image forming units ten times. A continuous test was performed at a speed of copying 28 sheets per minute after the temperature of the fixing portion reached a constant temperature, and the cleaning performance after 100,000 sheets was good.

[Comparative Example 3]
In Example 12, the toner particles were also modified by passing the toner particles in hot air. When observed with an electron microscope, the toner particles were clearly rounded and rounded. The circularity of the toner particles was 0.96. A developer was prepared with this black toner in the same manner as in Example 12 and set in the developing section A. Further, yellow, magenta, and cyan toner developers were used in Example 12, and each color developer was set at the same position as in Example 12 and tested in the same manner as in Example 12. There was a poor cleaning and the cleaning performance was not very good.

[Comparative Example 4]
In Example 12, the yellow, magenta, and cyan toner particles are not treated with hot air. The circularity of each toner particle was 0.79. Using each color toner and the black toner of Example 12, a developer was prepared in the same manner as in Example 12. The developing portions for the respective colors were set in the same manner as in Example 12. When tested in the same manner as in Example 12, no defective cleaning occurred on the initial copy paper. However, since the character portion was slightly unclear, the toner filling was not sharp and the resolution was not good when observed with a magnifying glass. Also, the gradation of the halftone was not good, and the image was noticeably rough.

A color toner was obtained by the following toner formulation.
[Binder resin] Polyester resin (Propylene oxide adduct of bisphenol A, polyester synthesized from terephthalic acid and succinic acid derivative): 100 parts [Charge control agent] Zinc salicylate (Bontron E84, Orient Chemical) 2 parts [Colorant ]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant)):
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink)):
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

  Each color toner was preliminarily kneaded with a mixer and then melt kneaded with a three-roll mill at each prescribed amount. Next, the kneaded product was cooled, coarsely pulverized to 0.5 to 3 mm, and then pulverized by an IDS2 type jet pulverizer. Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07. Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner.

On the other hand, the carrier was produced as follows.
First, a coating solution was prepared according to the following formulation.

Silicone resin SR2411 (Toray Dow Corning) 300 parts Toluene 1200 parts

Next, the coating liquid was put in a rotating disk type fluidized bed coating apparatus together with 5 kg of ferrite carrier having an average particle diameter of 50 μm to coat the carrier. Thereafter, the coating was taken out from the apparatus and heated at 250 ° C. for 2 hours to age the film. In order to test by setting in a copying machine, a developer was prepared by weighing so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g. Each color developer was set at the same position as in Example 12 and tested in the same manner as in Example 12. As a result, the same result as in Example 12 was obtained.

  In Example 13, except that the charging step was changed from the scorotron charger to the roller charger of FIG. 3, the same configuration as in Example 13 was tested in the same manner as in Example 13, and the same result as in Example 13 was obtained.

  In Example 13, the charging process was changed from the scorotron charger to the roller charger of FIG. Further, the same results as in Example 13 were obtained when tested in the same manner as in Example 13 with the same configuration as in Example 13 except that the fixing unit was replaced with the belt fixing in FIGS.

  In Example 15, a polyol resin synthesized from polyester by using low molecular weight bisphenol A type epoxy, high molecular weight bisphenol A type epoxy, glycidylated product of bisphenol A type ethylene oxide adduct, bisphenol F, and P-cumylphenol. The same results as in Example 15 were obtained when tested in the same manner as in Example 15 with the same configuration as in Example 15 except that it was replaced.

A color toner was obtained by the following toner formulation.
[Binder Resin] 100 parts of polyol resin synthesized from low molecular weight bisphenol A type epoxy, high molecular weight bisphenol A type epoxy, glycidylated product of bisphenol A type ethylene oxide adduct, bisphenol F and P-cumylphenol ] Zinc salicylate (Bontron E84, Orient Chemical) 2 parts [Release agent] Carnauba wax 3.5 parts [Colorant]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant))
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink))
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

Each color toner was preliminarily kneaded with a mixer and then melt kneaded with a three-roll mill at each prescribed amount. This grinding is performed in the same manner as in Example 12.
Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07. Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner. And when it tested similarly to Example 16, the same result as Example 16 was obtained.

A color toner was obtained by the following toner formulation.
[Binder Resin] Polyester resin (Propylene oxide adduct of bisphenol A, polyester synthesized from terephthalic acid and succinic acid derivative): 100 parts [Release agent] Carnauba wax: 3.5 parts [Charge control agent] Zinc salicylate Salt (Bontron E84, Orient Chemical) 2 parts [Colorant]
Yellow colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))
Magenta colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant))
Cyan colorant: C.I. I. Pigment Blue 15: 3 2 parts
(Lionol Blue FG-7351 (Toyo Ink))
Black colorant: Carbon black (# 44 Mitsubishi Chemical): 7.5 parts

The toners of the respective colors were preliminarily kneaded with a mixer and then melt kneaded with a three roll mill at each prescribed amount. This pulverization was performed in the same manner as in Example 12.
Then, classification was performed to obtain a toner having an average particle diameter of 7.75 μ, a number% of 5 μm or less of 12.85, and a volume% of 16 μ or more of 0.07. Among the toner particles, yellow, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the yellow, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated black toner particles. Further, the circularity of the black toner particles was 0.88, and the circularity of the yellow, magenta and cyan toner particles was 0.96. To 100 parts by weight of the toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.6 part to prepare a negatively charged developing toner. And when it tested similarly to Example 16, the same result as Example 16 was obtained.

  In Example 14, the constitution of the toner was as shown in Table 4 below.

Among the toner particles, black, magenta and cyan toners were passed through hot air to modify the toner particle surface. When the toner particles were observed with an electron microscope, the black, magenta and cyan toner particles were clearly rounded and rounded compared to the untreated yellow toner particles. The circularity of the yellow toner particles was 0.88, and the circularity of the magenta, cyan and black toner particles was 0.97.
This developer was set with a yellow developer in the developing section A of the apparatus shown in FIG. 2, a magenta developer in the developing section B, a cyan developer in the developing section C, and a black developer in the developing section D. And when it tested similarly to Example 16, the same result as Example 16 was obtained.

A polymerized toner was prepared as follows.
<Production example of black toner>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Colorant: 7.5 parts of carbon black
(Carbon black # 44, manufactured by Mitsubishi Chemical Corporation)

The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner.
On the other hand, the carrier of Example 13 was used as a carrier so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g to prepare a developer.

<Example of yellow toner>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Colorant: C.I. I. 5 parts of Pigment Yellow 180
(PV Fast Yellow HG (Clariant))

  The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner. On the other hand, the carrier of Example 13 was used as a carrier, and a developer was prepared by weighing the total amount of the toner and the carrier to 1000 g so that the toner concentration was 5%.

<Magenta toner production example>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Colorant: C.I. I. Pigment Red 122 4 parts
(Hostaperm Pink E (Clariant))

  The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner. On the other hand, the carrier of Example 13 was used as a carrier so that the toner concentration was 5% and the total amount of the toner and the carrier was 1000 g to prepare a developer.

<Example of cyan toner production>
Styrene monomer 90 parts n-butyl methacrylate 55 parts Charge control agent: zinc salicylate 3.5 parts
(Bontron E84, manufactured by Orient Chemical Co., Ltd.)
Cyan colorant: C.I. I. Pigment Blue 15: 3 2.5 parts
(Lionol Blue FG-7351 (Toyo Ink))

The above was blended, put into a reaction vessel together with a polymerization initiator (2,2-azobisisobutyronitrile), polymerization was conducted, the polymerization was stopped at a particle size of 6.8 μm, and the granulated particles were washed with water. And dried to obtain polymerized toner particles. The toner particles were spherical when observed with an electron microscope. The circularity of this toner was 0.98. To 100 parts by weight of this toner, silica fine powder R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed at a ratio of 0.5 to prepare a negatively chargeable developing toner. On the other hand, the carrier of Example 13 was used as a carrier, and a developer was prepared by weighing the total amount of the toner and the carrier to 1000 g so that the toner concentration was 5%.
The configuration of the toner set in FIG. 2 is as shown in Table 5 below.

  And when it tested like Example 15, the result same as Example 15 was obtained.

  The structure of the toner set in FIG. 2 in Example 20 is as shown in Table 6 below.

  And when it tested like Example 15, the result same as Example 15 was obtained.

  In Example 12, the developer in the developing section A was set in the developing section D. In addition, the developer of the developing unit D was set in the developing unit A, and the two developers were replaced and set. Then, after the power is turned on, only the fourth image forming unit develops the solid image until the roller temperature of the fixing unit reaches a constant temperature. At that time, the solid image is transferred onto the intermediate transfer member without supplying the transfer paper (not passing the toner). The toner image on the intermediate transfer member is passed through the second, third, and fourth image forming portions. Thereafter, the transport belt is added with an operation for performing a process of cleaning in the cleaning unit. A continuous test was performed at a speed of copying 28 sheets per minute after the temperature of the fixing portion reached a constant temperature, and the cleaning performance after 100,000 sheets was good.

  According to the color image forming method of the present invention, good cleaning properties can be obtained even when the blade cleaning method is used, and a high-quality image can be stably obtained. High usability.

It is the schematic of an example of the image forming apparatus using the method of this invention. It is the schematic of an example of the image forming apparatus using the method of this invention. It is the schematic which shows an example of roller charging. It is the schematic which shows an example of fur brush charging. It is the schematic which shows an example of roller fixing. It is the schematic which shows an example of belt fixing. It is the schematic which shows an example of surf fixing. It is sectional drawing which shows arrangement | positioning of the exciting coil of the induction heating means in an IH fixing device. It is a side view of FIG. 12 which shows arrangement | positioning of an exciting coil. It is sectional drawing which shows schematic structure of the developing device which applies an alternating electric field. It is a figure for demonstrating the layer structure of an amorphous silicon photoconductor. It is a figure which shows schematic structure of a process cartridge.

Explanation of symbols

1A, 1B, 1C, 1D latent image carrier 2A, 2B, 2C, 2D charging member 3A, 3B, 3C, 3D exposure 4A, 4B, 4C, 4D developing unit 5A, 5B, 5C, 5D transfer unit 6A, 6B, 6C, 6D, cleaning unit 1 electrostatic latent image carrier 2 roller charger 3 cored bar 4 elastic layer 5 protective layer 6 cleaning member 7 intermediate transfer member 8 transfer paper 9 intermediate transfer member cleaning means 10 transfer unit (FIG. 2), High voltage power supply (Figure 3)
DESCRIPTION OF SYMBOLS 11 Fur brush 12 Brush roller 13 Core metal 14 Power supply 21, 31 Fixing roller 22, 32 Pressure roller 23, 33 Cleaning member 24, 34 Heat-resistant release layer 25, 35 Separation claw 26, 36 Felt, Oil application material 27, 37 Lamp 28, 38 Transfer paper 29, 39 Toner 30 Silicon oil 31 Belt 32 Support roller 41 Fixing film 42 Drive roller 43 Followed roller 44 Heating body 45 Pressure roller 46 Transfer material 47 Planar substrate 48 Fixing heater 49 Fixing temperature sensor 61 Heating roller 62a, 62b, 62 Fixing roller 63 Belt 64 Pressure member 64a Core metal 64b Elastic member 65
66 Induction heating means 67 Excitation coil 68 Coil guide plate 69 Excitation coil core 70 Excitation coil core support member 71 Recording material 80 Developer 81 Development sleeve 82 Power supply 83 Development section 84 Photosensitive drum 91 Process cartridge 92 Latent image carrier 93 Charging means 94 developing means 95 cleaning means 501 support 502 photoconductive layer 503 surface layer 504 charge injection blocking layer 505 charge generation layer 506 charge transport layer

Claims (14)

A step of charging the first electrostatic latent image carrier, a step of forming a color-separated electrostatic latent image on the first electrostatic latent image carrier, and a first electrostatic latent image containing color toner A A step of developing the electrostatic latent image in a developing unit for developing the image, a step of transferring the developed first toner image to the transfer member, and cleaning the electrostatic latent image carrier after transferring the first toner image. A step, a step of charging the second electrostatic latent image carrier, a step of forming a color-separated electrostatic latent image on the second electrostatic latent image carrier, and a second storing the color toner B A step of developing the electrostatic latent image in a developing unit for developing the electrostatic latent image of the toner, a step of transferring the developed second toner image onto the transfer member to which the first toner image is transferred, and a second toner image. A step of cleaning the latent electrostatic image bearing member after transfer, a step of charging the third latent electrostatic image bearing member, a third latent electrostatic latent image Forming a color-separated electrostatic latent image on the carrier, developing a third electrostatic latent image containing color toner C in a developing unit for developing the electrostatic latent image, and developing the developed third A step of superimposing and transferring the toner image onto the transfer member to which the second toner image is transferred, a step of cleaning the electrostatic latent image carrier after transferring the third toner image, and a fourth electrostatic latent image carrier. A step of charging, a step of forming a color-separated electrostatic latent image on a fourth electrostatic latent image carrier,
The step of developing the electrostatic latent image in the developing unit that develops the fourth electrostatic latent image containing the color toner D, and the transferred fourth toner image overlaid on the transfer member to which the third toner image is transferred An image forming method comprising: a step of cleaning the latent electrostatic image bearing member after transferring a fourth toner image; and a step of fixing the toner images successively transferred onto the transfer member by heat and pressure. One or more of the A, B, C, and D toners is a spherical toner having a circularity of 0.94 to 0.99, and the other one or more toners have a circularity of 0.85 to 0.00. 93. A color image forming method, wherein the toner is 93 irregular toner.   A step of charging the first electrostatic latent image carrier, a step of forming a color-separated electrostatic latent image on the first electrostatic latent image carrier, and a developing unit for developing the first electrostatic latent image The step of developing the electrostatic latent image with the color toner A stored therein, the step of once transferring the developed first toner image to the intermediate transfer member, and carrying the electrostatic latent image after transferring the first toner image Cleaning the body, charging the second electrostatic latent image carrier, forming a color-separated electrostatic latent image on the second electrostatic latent image carrier, second static The process of developing the electrostatic latent image by storing the color toner B in the developing unit that develops the electrostatic latent image, and the developed second toner image is temporarily transferred onto the intermediate transfer member to which the first toner image is transferred. A step of cleaning the latent electrostatic image bearing member after transferring the second toner image, and then charging the third latent electrostatic image bearing member. A step of forming a color-separated electrostatic latent image on a third electrostatic latent image carrier, and a color toner C is stored in a developing unit for developing the third electrostatic latent image to form an electrostatic latent image. The step of developing, the step of transferring the developed third toner image once onto the intermediate transfer member to which the second toner image is transferred, and cleaning the electrostatic latent image carrier after transferring the third toner image A step of charging the fourth electrostatic latent image carrier, a step of forming a color-separated electrostatic latent image on the fourth electrostatic latent image carrier, and a fourth electrostatic latent image A step of developing the electrostatic latent image by storing the color toner D in the developing portion to be developed, a step of temporarily transferring the developed fourth toner image onto the intermediate transfer member to which the third toner image is transferred, 4, after the toner image is transferred, the electrostatic latent image carrier is cleaned and sequentially transferred to the intermediate transfer member. The toner image is formed by an image forming method comprising a step of batch-transferring to a transfer paper and then fixing by heat and pressure. One or more of the toners of each of A, B, C, and D colors has a circularity of 0.94 to 0. 99. A color image forming method, wherein the toner is a non-spherical toner having a circularity of 0.85 to 0.93.   3. The color image forming method according to claim 1, wherein the step of cleaning the electrostatic latent image carrier after the transfer step is performed by a blade cleaning method.   4. The color image forming method according to claim 1, wherein the binder resin of the toner particles is polyester.   The color image forming method according to claim 1, wherein the binder resin of the toner particles is a polyol.   6. The color image forming method according to claim 1, wherein the toner particles contain a release agent.   The color image forming method according to claim 1, wherein the irregularly shaped toner particles are black toner.   8. The color image forming method according to claim 1, wherein the step of charging the electrostatic latent image carrier is performed by a roller charging member.   The color image forming method according to claim 1, wherein the fixing of the toner in the fixing step is performed by a pair of rollers with a fixing belt interposed therebetween.   The color image forming method according to claim 1, wherein an alternating electric field is applied when the latent image on the electrostatic latent image carrier is developed.   11. The color image forming method according to claim 1, wherein the electrostatic latent image carrier is an amorphous silicon photoconductor.   A fixing device used in the fixing step includes a heating body including a heating element, and a pressure member that presses the heating body through a film that contacts the heating body, and the film and the pressure member The color image forming method according to claim 1, wherein the fixing device heats the recording material on which an unfixed image is formed by passing through the recording material.   A fixing device used in the fixing process includes a heating roller made of a magnetic metal and heated by electromagnetic induction, a fixing roller arranged in parallel with the heating roller, and a stretcher between the heating roller and the fixing roller. An endless belt-shaped toner heating medium heated by the heating roller and rotated by the rollers, and pressed against the fixing roller via the toner heating medium, and forwardly directed to the toner heating medium. The color image forming method according to claim 1, wherein the fixing device includes a pressure roller that rotates to form a fixing nip portion.   A process cartridge for use in an image forming apparatus main body for carrying out the color image forming method according to claim 1, wherein the process cartridge is selected from an electrostatic latent image carrier, a charging unit, a developing unit, and a cleaning unit. A process cartridge which integrally supports at least one means and is detachable from the main body of the image forming apparatus.

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