JP2003076218A - Apparatus and method for forming electrophotographic image, process cartridge and electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for forming an electrophotographic image which has no jitter caused by vibration of a photoreceptor drum, etc., and the ruled line of which has not the width and density unevenly fluctuated and to provide a process cartridge and an electrophotographic photoreceptor. SOLUTION: The organic electrophotographic photoreceptor of this apparatus has a photosensitive layer formed on a cylindrical electrically conductive support, a mass accretion disposed on the inside and a siloxane-based resin layer as the surface layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, an image forming method, a process cartridge and a photoconductor used in a copying machine, a printer and the like.

[0002]

2. Description of the Related Art In recent years, as an electrophotographic photosensitive member (hereinafter also referred to as a photosensitive member), an organic electrophotographic photosensitive member containing an organic photoconductive substance (hereinafter also referred to as an organic photosensitive member) has been most widely used. Organic photoconductors are advantageous over other photoconductors because it is easy to develop materials for various exposure light sources from visible light to infrared light, materials that do not cause environmental pollution can be selected, and manufacturing costs are low. However, there is a problem that the mechanical strength is weak, the surface of the photoconductor is easily deteriorated or scratched when a large number of sheets are copied or printed, and the durability is insufficient. As a problem for improving the durability, it has been strongly demanded to suppress abrasion due to rubbing of a cleaning blade or the like. As an approach for that purpose, techniques such as providing a high-strength protective layer on the surface of the photoconductor have been studied. For example, JP-A-6-118681 reports that a curable siloxane-based resin containing colloidal silica is used as the surface layer of a photoreceptor. However, in the protective layer made of only silica in which siloxane bonds (Si-O-Si bonds) are three-dimensionally repeated, cracks are generated on the surface, adhesion to the photosensitive layer is deteriorated, This is a problem because the electrostatic properties of the photosensitive layer are deteriorated.

Further, as an attempt to improve the abrasion resistance and the adhesion to the photosensitive layer, an organic-inorganic hybrid polymer having both properties of an organic polymer and a crosslinked siloxane component has been proposed. For example, Japanese Patent Laid-Open No. 2000-22
In 1723, a protective layer containing a polymer in which polysiloxane and a silyl group-containing vinyl resin are chemically bonded is reported as a protective layer for an electrophotographic photoreceptor. However, a photoreceptor having such a protective layer has improved mechanical abrasion resistance, but has insufficient electrophotographic characteristics during repeated use and is apt to cause fog and image blur. The photoreceptor having a layer was unsuitable as the most widely used electrophotographic photoreceptor such as the Carlson process.

Therefore, the present inventors have a charge transporting property-imparting group as a protective layer for an electrophotographic photosensitive member which simultaneously satisfies mechanical abrasion resistance and electrophotographic characteristics during repeated use.
In addition, a siloxane resin layer having a crosslinked structure has been proposed as a protective layer for a photoreceptor (Japanese Patent Application No. 11-70308).
issue). However, these siloxane-based resins have improved electrophotographic characteristics (charge, sensitivity, residual potential characteristics, etc.) during use,
Although it has sufficient practicality as a highly durable organic electrophotographic photoreceptor, it seems to be a characteristic of siloxane-based resin, but after repeated use, it becomes a protective layer with strong elastic behavior, and a cleaning device using a cleaning blade. With,
The torque between the photoconductor and the cleaning blade was increased, and the cleaning performance of the toner and the stability of the blade against curling often deteriorated. In particular, due to variations in hardness, friction coefficient, contact angle, pressure bonding force of the cleaning blade, and roundness and eccentricity of the photosensitive drum, the cleaning blade does not slide smoothly on the surface of the photosensitive drum and jumps and chatters. It is apt to occur, and the occurrence of this chattering often causes a problem that the photoconductor drum resonates and produces an unpleasant sound, and a so-called cleaning blade squeal occurs. As measures against this, Japanese Utility Model Laid-Open No. 62-127567 and Japanese Patent Laid-Open No. 63-271
388, JP-A-2-118684, and JP-A-3-0446.
89, 3-45981, 5-188671.
No. 8, 146686, WO-00 / 49466, etc., a filler, a vibration suppressor, an absorbing member, etc. are applied inside the photosensitive drum.

On the other hand, as for the electrophotographic image forming method, the digital image forming has become the mainstream due to the recent development of digital technology. The digital image forming method is basically based on visualizing a small dot image of one pixel such as 400 dpi (the number of dots per 2.54 cm), and an image quality improving technique that faithfully reproduces these small dot images. Is required. As one of the techniques for improving the image quality, there has been proposed an electrophotographic developer or an image forming method in which a toner having a small particle diameter or a toner particle has a uniform particle size distribution and shape, and a polymerized toner is used. The polymerized toner is produced by uniformly dispersing the raw material monomer in an aqueous system and then polymerizing the toner to obtain a toner having a uniform particle size distribution and shape. However, although these powder systems have complicated physical properties and have good sharpness and image quality, they have strong cohesive force and cause halftone unevenness, black spots, etc. due to cohesion and adhesion of the photoconductor and the toner itself. It was difficult to apply because cleaning defects such as filming and blade turning were likely to occur. That is, when a toner having a large adhesive force between the toner and the photoconductor, for example, a spherical toner, is used, a part of the toner on the photoconductor surface repeatedly passes through the cleaning section without being cleaned, and as a result, the cleaning blade Filming occurs on the surface of the photoconductor under the influence of the pressing force and the like. In the portion where the filming occurs, image defects such as image deletion and black spots are likely to occur. It has been found that these image defects are likely to occur in the photoconductor having the siloxane-based resin even if filming slightly occurs.

On the other hand, as a charging device for charging an object to be charged such as a photoconductor used in an image forming apparatus such as an electrophotographic apparatus, a corona discharge device has been generally used conventionally. However, in recent years, a contact charging device for bringing a roller-type or blade-type member into contact with a member to be charged has been adopted because it has advantages such as a low power supply voltage and an extremely small amount of ozone generated. Is being done. However, in the contact charging device, as the peripheral speed of the photosensitive drum increases, the frequency of the AC voltage applied to the charging roller must be increased in order to ensure uniform charging of the surface of the photosensitive drum. There is a problem in that the drum and the charging roller vibrate and an abnormal sound is generated, and therefore, there are problems in JP-A-5-035048, 6-019377,
As in No. 333615, various inserts have been tried to be used inside the photosensitive drum. In addition to such an abnormal sound being emitted as a direct sound from the contact portion between the photosensitive drum and the charging roller, the vibration of the photosensitive drum may be, for example,
It may be transmitted to the process cartridge or the image forming apparatus and converted into sound there, which complicates the situation.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus, an image forming method, which has no jitter due to vibrations in the photoconductor drum or the image forming apparatus, and has no unevenness such as ruled line width variation or density variation. A process cartridge and a photoreceptor are provided.

[0008]

The above object of the present invention can be achieved by the following means.

1. An electrophotographic photoreceptor having a photosensitive layer on a cylindrical conductive support, a charging means for charging the surface of the photoreceptor, and an electrostatic latent image by exposing the surface of the photoreceptor charged by the charging means. Exposing means for forming a toner image, developing means for forming a toner image by visualizing the electrostatic latent image formed by the exposing means, and transfer means for transferring the toner image formed by the developing means to a transfer target. And an electrophotographic image forming apparatus having a cleaning unit that removes foreign matter such as toner remaining on the surface of the photoconductor after the transfer by the transfer unit, while providing a mass addition member inside the photoconductor, An electrophotographic image forming apparatus, wherein the photoconductor is an organic photoconductor containing a siloxane resin as a surface layer.

2. 2. The electrophotographic image forming apparatus according to claim 1, wherein at least a part of the mass addition body or a part of a member including the mass addition body is in contact with the inner surface of the photoconductor.

3. 2. The electrophotographic image forming apparatus described in 1 above, wherein the mass addition body is a vibration suppressing material.

4. 2. The electrophotographic image forming apparatus described in 1, wherein the mass addition body is a sound absorbing material.

5. 2. The electrophotographic image forming apparatus as described in 1 above, wherein the siloxane-based resin has a structural unit having a charge transporting property and also has a crosslinked structure.

6. 2. The electrophotographic image forming apparatus as described in 1 above, wherein the siloxane resin has a thermoplastic organic polymer component.

7. 2. The electrophotographic image forming apparatus as described in 1 above, wherein a toner having a variation coefficient of shape factor of 16% or less and a variation coefficient of number in number particle size distribution of 27% or less is used as the toner.

8. The toner has a shape factor of 1.0 to 1.
8. The electrophotographic image forming apparatus described in any one of 1 to 7 above, which contains 65% by number or more of toner particles in the range of 6.

9. The toner has a shape factor of 1.2 to 1.
8. The electrophotographic image forming apparatus described in any one of 1 to 7 above, which contains 65% by number or more of toner particles in the range of 6.

10. 1 to 9 above, wherein the toner contains 50% by number or more of toner particles having no corners
The electrophotographic image forming apparatus according to claim 1.

11. The number average particle diameter of the toner is 3 to 8
1 μm, any one of claims 1 to 10 characterized in that
An electrophotographic image forming apparatus according to the item 1.

12. The particle size of the toner particles is D (μm)
Where the natural logarithm lnD is taken as the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23, and the relative frequency (m1) of toner particles included in the most frequent class in the histogram showing the number-based particle size distribution. And the relative frequency (m2) of the toner particles included in the most frequent class next to the most frequent class, the sum (M) is 70% or more.
11. The electrophotographic image forming apparatus according to any one of 11.

13. 13. The electrophotographic image forming apparatus according to any one of 1 to 12 above, wherein the toner is obtained by polymerizing at least a polymerizable monomer in an aqueous medium.

14. 14. The electrophotographic image forming apparatus as described in any one of 1 to 13 above, wherein the toner is obtained by salting out / fusing at least resin particles in an aqueous medium.

15. 1 to 14, wherein the toner is a styrene- (meth) acrylate resin
The electrophotographic image forming apparatus according to claim 1.

16. 16. The electrophotographic image forming apparatus according to any one of 1 to 15 above, wherein the cleaning unit is a polyurethane cleaning blade.

17. 17. The electrophotographic image forming apparatus described in any one of 1 to 16 above, wherein the charging unit is contact charging.

18. 18. An electrophotographic image forming method using the electrophotographic image forming apparatus according to any one of 1 to 17 above.

19. The electrophotographic image forming apparatus according to any one of 1 to 17 above is used, and at least one of a charging unit, an exposing unit, a developing unit, a transferring unit, and a cleaning unit is combined with an electrophotographic photosensitive member to form an image forming apparatus. A process cartridge characterized by being formed so as to be able to be integrally taken in and out of a main body.

20. In an electrophotographic photoreceptor having a photosensitive layer on a cylindrical conductive support, a mass addition body is provided inside the photoreceptor, and the photoreceptor is an organic photoreceptor having a siloxane resin layer as a surface layer. An electrophotographic photoreceptor characterized by the above.

The present invention will be described in detail below. In order to obtain a high-quality image with high durability and an excellent image with high sharpness, the present inventors have added a siloxane resin to the surface layer of the photoconductor to improve the durability and the friction property. , Another problem, halftone unevenness, occurs especially under high temperature and high humidity,
I can no longer expect high durability. It has been found that the cause of this is that vibration of the photoconductor or the device increases the number of poor elastic properties after repeated use, which is a drawback of the siloxane resin. Vibration of the device is especially cleaning and contact charging (other than contact charging, there is corona charging that does not directly contact the photoconductor as charging means, but contact charging has advantages such as low power supply voltage and small ozone generation amount. A point of contact with the photosensitive drum, such as (preferably used), is a generation source. This problem can be solved by inserting a mass addition product into the photoreceptor, and the advantages of the siloxane-based resin can be utilized. The difficulty in solving the technical problem of this case is that halftone unevenness occurs even if the noise is not large enough to be heard.

The present inventors insert a mass adder into the photoconductor having a siloxane-based resin in the surface layer and the photoconductor drum, so that jitter does not occur due to abnormal noise such as chattering or abnormal vibration. It has high durability and high image quality without halftone density unevenness, black spots, etc., and does not cause toner filming, blade flipping or toner scattering.
Moreover, they have found that uneven wear of the photoconductor does not occur.

That is, if a photoreceptor containing a siloxane resin in the surface layer is used as in the present invention, the durability is extended, but half-tone unevenness occurs at a point where it is not so expected. It was As a result of diligent pursuit by the present inventors, it was found that this was due to vibration and jitter coming from the photoconductor or the device, and because the dot reproducibility was good, it was sensitive to jitter due to vibration in the photoconductor drum or the device, It is judged that variations in diameter and variations in density are easily detected as unevenness.

By inserting a mass addition member inside the photosensitive drum, abnormal noise and abnormal vibration are reduced, and a jitter component is suppressed, so that there is no blade curling or uneven wear, and the stability of repeating characteristics is good. It became possible to eliminate halftone unevenness and adopt high quality toner.

This abnormal sound has a strong viscoelasticity of the surface layer of the photoconductor and a strong cohesive force between the photoconductor and the particles of the toner, which makes cleaning difficult and causes blade chattering, curling, and uneven wear. Had been one cause. That is, the cleaning blade does not slide smoothly on the surface of the photosensitive drum and jumps to cause chattering, and the occurrence of chattering causes the photosensitive drum to resonate and vibrate to produce an unpleasant sound, a so-called cleaning blade squeal, abnormal noise. It is presumed that, even when the charging roller is used, the noise is generated from the charging roller and the photoconductor, vibrates the photoconductor, and causes abnormal noise.

[0034]

DETAILED DESCRIPTION OF THE INVENTION [Image Forming Process] An example of an image forming process will be described below with reference to the drawings.

FIG. 1 is a block diagram of an electrophotographic printer as an example of the image forming apparatus of the present invention.

Reference numeral 1 is a photosensitive drum, and a photosensitive material such as OPC is formed on a cylinder-shaped or belt-shaped base made of aluminum or nickel. In this embodiment, it has a cylindrical shape. The photosensitive drum 1 is uniformly charged by the charging roller 2. Next, the laser scanner 3 performs a raster scanner exposure based on the image signal. The laser scanner 3 scans the blinking of the semiconductor laser with a polygon scanner, and irradiates the photosensitive drum 1 with the optical system. As a result, an electrostatic latent image is formed on the photosensitive drum 1. The formed electrostatic latent image is developed by the developing device 4. Development is jumping development, two-component development, FEE
D development or the like is used, and the image area is used in combination with reversal development in which a laser is irradiated to reduce the potential and toner is attached.

The developed toner image is transferred to a transfer material. The transfer material is contained in the cassette 5 and is fed one by one by the paper feed roller 6. When the print signal is sent from the host computer, the paper is fed by the paper feed roller 6, and the toner image is transferred onto the transfer material by the transfer roller 8 by the transfer roller 7 in synchronization with the image signal. The transfer roller 8 is an electrically conductive elastic body having a low hardness, and is electrostatically transferred by a bias electric field in a nip portion formed by the photosensitive drum 1 and the transfer roller 8.

The transfer material on which the toner image has been transferred is fixed by the fixing device 9, sent out of the device by the paper discharge roller 10, and discharged to the paper discharge tray 11. On the other hand, the toner remaining after transfer is
The cleaning device 12 cleans the blade.

FIG. 2 is a sectional view of a process cartridge which can be attached to and detached from the image forming apparatus shown in FIG. 1. The process cartridge C supports the photosensitive drum 1, the charging roller 2 as a charging member, the developing device 4, and the cleaning device 12. is doing. Further, this process cartridge C is a photosensitive drum 1.
A shutter 14 is provided to protect the. Here, the process cartridge C may include at least the photosensitive drum 1 which is an image carrier and the charging roller 2 which is a charging member.

FIG. 3 is a block diagram showing an example of a photosensitive drum as a member to be charged and a charging roller as a contact charging device according to the present invention.

In FIG. 3, 1 is a photosensitive drum,
It is composed of a conductive support 1a made of aluminum and having a thickness of about 1 mm, which is connected to the ground, and a photosensitive layer 1b formed on the outer peripheral surface of the support 1a, and has an outer diameter of 30 mm and a predetermined diameter in the direction of arrow A. It is driven to rotate at a peripheral speed of.

Numeral 2 is a charging roller, and an example of the structure is composed of a conductive core metal 2a made of SUS and a conductive elastic layer 2b made of urethane rubber containing carbon formed on the outer peripheral surface thereof. The outer diameter thereof is 12 mm, and the photosensitive drum 1 is provided with spring members (not shown) at both ends in the longitudinal direction (direction perpendicular to the paper surface of FIG. 3) of the conductive cored bar 2a.
It is pressed against the surface and is driven to rotate.

The charging roller 2 is connected to the high voltage power source 1
By applying a predetermined voltage by 3, the surface of the photosensitive drum 1 is charged to a predetermined potential. The voltage applied to the charging roller 2 is preferably an oscillating voltage obtained by superimposing an AC voltage on a DC voltage. The oscillating voltage mentioned here is a voltage whose voltage value periodically changes with time, and the oscillating voltage is a peak-to-peak voltage that is at least twice the charging start voltage of the surface of the photosensitive drum 1 when only a DC voltage is applied. It is preferable to have uniform charging, and the waveform is not limited to a sine wave, and may be a rectangular wave, a triangular wave, or a pulse wave, but from the viewpoint of charging sound, a sine wave that does not include harmonic components is preferable. . Further, the oscillating voltage may be a pulse waveform formed by turning on and off a DC voltage.

Further, inside the photosensitive drum 1, the above-mentioned mass adding member is inserted. For example, a polyurethane thin plate 15 having an outer diameter substantially equal to the inner diameter of the photosensitive drum 1 and contacting the inner surface of the photosensitive drum 1 with self-elasticity.
However, it is included over the entire effective charging width of the charging roller 2 that contacts the photosensitive drum 1 (see FIG. 4).

The photosensitive drum of the process cartridge is freely driven to rotate, and a desired voltage can be applied to the charging roller by an external high voltage power source.

Next, the constituent materials, devices and the like according to the present invention will be specifically described. [Photoreceptor] << Mass Adder >> According to the present invention, as will be described later, a mass adder such as a vibration suppressing material or a sound absorber is provided inside the photosensitive layer containing a siloxane resin in the surface layer and the photosensitive drum. By inserting or filling the material, a photoreceptor having high resolution, high image quality and high durability can be obtained.

The vibration suppressing material that should absorb the resonance has elasticity over a wide range as a condition for preventing the propagation of vibration, and has a mass for shifting the resonance frequency, like the vibration damping material used in general equipment. Required to have. Therefore, the vibration suppressing material or the sound absorbing material provided inside or on the inner surface of the photosensitive drum is preferably an elastic material that is pressed against or filled with a mass object such as a small piece or the inner surface of the drum with a surface as wide as possible. . Further, the means for fixing the vibration suppressing material to the inner surface of the drum is preferably of a type in which the vibration suppressing material is securely adhered by an adhesive or the vibration suppressing material itself is securely held.

Regarding the disposition position inside the photosensitive drum, it may be disposed at the end portion in the longitudinal direction of the photosensitive drum or may be disposed at the central portion. Further, it is preferable that it is in contact with the inner surface of the photosensitive drum, so that the vibration can be effectively suppressed, and the generation of charging noise due to this can be suppressed.

As the mass addition body, a vibration suppressing material, for example,
Resins such as metal pieces, wood, polyacetal resin, polymethylmethacrylate, fluorine, silicone, polycarbonate, polyphenylene sulfide, and mass materials such as SUS and brass metals are preferable. Further, sound absorbing materials such as glass wool, rock wool, polyurethane, polybutadiene rubber, polystyrene, styrene butadiene rubber, nitrile butadiene rubber, synthetic resins such as polyamide elastomers, porous materials such as synthetic rubber and natural rubber, viscoelastic materials, etc. Good.

The mass of the mass addition product is preferably 3 g or more, and more preferably 5 g or more. Further, 3% or more, preferably 5% or more, of the mass of the photoreceptor including the flange is preferable.

The siloxane-based resin used in the present invention means an organic polymer containing a siloxane bond, preferably Japanese Patent Application Nos. 2000-220536 and 2000-32.
6794, 2001-36883. That is, it is a resin having at least a siloxane condensate component and a charge transporting structural component, and optionally a thermoplastic organic polymer component, and preferably a crosslinked structure.

<Support> The support used in the photoreceptor of the present invention is 1) a metal plate such as aluminum or stainless steel or a cylindrical tube 2) a support such as paper or a plastic film, and aluminum, palladium, gold, etc. 3) A thin metal layer formed by laminating or vapor deposition 3) A substrate such as a paper or plastic film on which a layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide is formed by coating or vapor deposition 4) ) Alumite or an alumite base material which has been subjected to a pore-sealing treatment. A cylindrical tube of aluminum is preferable.

Recently, with the downsizing of electrophotographic apparatus, the electrophotographic photosensitive member tends to be smaller and lighter, and the diameter of the aluminum cylinder as the conductive support is φ3.
0 is the mainstream.

Conventionally, such a small-diameter photosensitive drum has been used in a low-speed machine. However, in order to meet the demands for downsizing, space saving, cost reduction of a copying machine or printer body, the present invention is also applicable to the above. It may be applied to a small diameter drum.

The photosensitive layer used in the present invention may have various constitutions, but in the present invention, the photosensitive layer is preferably a laminated type function-separated type photosensitive layer. In this case, the charge transport layer, the charge generation layer, and the protective layer are sequentially laminated on the conductive support through the intermediate layer, and the adhesive layer is interposed between the charge generation layer and the protective layer. A charge transport layer, a charge generation layer, and a protective layer are sequentially laminated on a conductive support, and an intermediate layer, a charge transport layer, a charge generation layer, and a protective layer are sequentially laminated on a conductive support. There are also things. Further, a charge transport material may be contained in the charge generation layer.

<Intermediate Layer> The intermediate layer (UCL) used in the photoreceptor of the present invention is a support in order to improve the adhesion between the conductive support and the photosensitive layer or to prevent charge injection from the support. The material for the intermediate layer, which is provided between the photosensitive layers, includes a polyamide resin, a vinyl chloride resin, a vinyl acetate resin, and a copolymer resin containing two or more of the repeating units of these resins. Among these resins, a polyamide resin is preferable as a resin that can reduce the increase in residual potential due to repeated use. The thickness of the intermediate layer using these resins is preferably 0.01 to 0.5 μm.

The intermediate layer most preferably used in the present invention is an intermediate layer using a curable metal resin obtained by thermosetting an organic metal compound such as a silane coupling agent and a titanium coupling agent. The film thickness of the intermediate layer using the curable metal resin is preferably 0.1 to 2 μm.

Another preferred intermediate layer is a layer containing titanium oxide and a binder resin, in which titanium oxide is dispersed and applied in a binder resin solution.

Titanium oxide can be used in various crystal forms, particle sizes and surface-treated substances. A substance having an anatase crystal form and a particle diameter of 0.02 to 0.5 μm is preferable, and a substance in a state where no surface treatment is performed or a substance which is surface-treated with an organic silane is preferable.

As the binder resin for the intermediate layer, a polyamide resin which disperses titanium oxide well and has good adhesiveness to the support and the layer provided on the intermediate layer is preferable, but the binder resin is not limited thereto. Not a thing.

<Charge Generating Layer> The charge generating layer used in the photoreceptor of the present invention contains a charge generating substance and a binder resin, and is formed by dispersing and coating the charge generating substance in a binder resin solution.

The charge generating substance is a known phthalocyanine compound, preferably a titanyl phthalocyanine compound and a hydroxygallium phthalocyanine compound.
Furthermore, Y type and A type (β type) of titanyl phthalocyanine
A titanyl phthalocyanine compound characterized by a main peak of Bragg angle 2θ with respect to Cu-Kα characteristic X-ray (wavelength 1.54Å) is preferable. These oxytitanyl phthalocyanines are described in JP-A-10-069107. Further, these charge generating substances may be used alone or in combination of two or more, for example, Y type and A type may be used, and they may be used by mixing with a polycyclic quinone, for example, a perylene pigment. Good.

As the binder resin of the charge generation layer, known resins can be used, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, Epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin,
Melamine resin, copolymer resin containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin), and poly-vinylcarbazole Examples of the resin include, but are not limited to, resins.

The charge generation layer is formed by dispersing a charge generation substance in a solution in which a binder resin is dissolved with a solvent to prepare a coating solution, and coating the coating solution with a coating machine to a constant film thickness. Then, the coating film is preferably dried to be manufactured.

As a solvent for dissolving and coating the binder resin used in the charge generation layer, for example, toluene,
Xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and diethylamine However, the present invention is not limited to these.

An ultrasonic disperser, a ball mill, a sand grinder, a homomixer or the like can be used as the means for dispersing the charge generating substance, but the means is not limited thereto.

Examples of the coating machine for forming the charge generation layer include, but are not limited to, a dip coating machine and a ring coater.

The mixing ratio of the charge-generating substance to the binder resin is preferably 1 to 600 parts, more preferably 50 to 5 parts, relative to 100 parts of the binder resin.
It is 00 copies. The thickness of the charge generation layer varies depending on the characteristics of the charge generation substance, the characteristics of the binder resin, the mixing ratio, etc., but is preferably 0.01 to 5 μm.

<Charge Transport Layer> The charge transport layer used in the photoreceptor of the present invention contains a charge transport substance and a binder resin, and is formed by dissolving and coating the charge transport substance in a binder resin solution.

The charge transporting material is described in Japanese Patent Application No. 2000-3609.
In addition to the charge-transporting substance represented by the general formula of 98, for example,
Carbazole derivative, oxazole derivative, oxadiazole derivative, thiazole derivative, thiadiazole derivative, triazole derivative, imidazole derivative, imidazolone derivative, imidazolidine derivative, bisimidazolidine derivative, styryl compound, hydrazone compound, pyrazoline compound, oxazolone derivative, benzimidazole derivative , Quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, triarylamine derivative, phenylenediamine derivative, stilbene derivative, benzidine derivative, poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9-vinyl Two or more kinds of anthracene and the like may be mixed and used.

As the binder resin for the charge transport layer, known resins can be used, such as polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic acid ester resin and styrene. -Methacrylic acid ester copolymer resin and the like can be mentioned, but polycarbonate is preferable. Furthermore, BPA, BPZ, dimethyl BP
A, BPA-dimethyl BPA copolymer and the like are preferable in terms of cracking and abrasion resistance charging characteristics.

The charge transport layer can be formed by dissolving a binder resin and a charge transport substance to prepare a coating solution, coating the coating solution with a coating machine to a constant thickness, and drying the coating film. preferable.

Examples of the solvent for dissolving the binder resin and the charge transport substance include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, and the like. Butanol, tetrahydrofuran, 1,4-dioxane,
Examples thereof include 1,3-dioxolane, pyridine and diethylamine, but are not limited thereto.

The mixing ratio of the charge transport material to the binder resin is preferably 10 to 500 parts, more preferably 20 to 500 parts, per 100 parts of the binder resin.
It is 100 copies.

The thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin, the mixing ratio, etc., but is preferably 10 to 100 μm, more preferably 1
It is 5 to 40 μm.

An AO agent, an EA agent, a stabilizer and the like may be added to the charge transport layer. Regarding AO agent, Japanese Patent Application No. 11-2
No. 00135, EA agent is JP-A-50-137543,
Those described in JP-A No. 58-76483 and the like are preferable.

<< Protective Layer >> In the present invention, in order to improve the durability of the photoreceptor, a protective layer is provided as the outermost layer, and a siloxane resin is contained therein. The siloxane-based resin may be contained in the charge transport layer. Known resins may be added as long as the siloxane-based resin is mixed in the protective layer. Examples thereof include a polycarbonate resin, a polyacrylate resin, a polyester resin, a polystyrene resin, a styrene-acrylonitrile copolymer resin, a polymethacrylic acid ester resin, and a styrene-methacrylic acid ester copolymer resin.

As an example of the siloxane resin, Japanese Patent Application No. 20
00-220536, 2000-326794, 2
001-36883, 2000-392497, 2
The compound etc. which are described in 001-19640 are mentioned.

The present invention will be described in more detail. [Charging] In addition to corona charging, contact charging that directly contacts the photoreceptor is effective as charging means. Direct charging has the advantage that the amount of ozone generated is small.

As the contact charging member of the present invention, various charging members such as a magnetic brush system, a charging roller system, a blade system, and a brush charging system can be used. Among them, the charging roller system or the magnetic brush system is used as the charging member. It is preferable because the uniformity of charging is easily obtained. The charging roller type charging means and the magnetic brush type charging means will be described below.

<< Charging Roller >> In the present invention, a charging roller composed of a conductive elastic member is brought into contact with a photosensitive member (image carrier), and a voltage is applied to the charging roller to move the photosensitive member (image carrier). Can be charged.

Such a charging roller system may be either a DC charging system for applying a DC voltage to the roller or an induction charging system for applying an AC voltage to the roller.

The frequency f of the voltage applied by the induction charging method is arbitrary, but in order to prevent strobing, that is, stripes, it is adjusted according to the relative speed of the conductive elastic roller and the image carrier member. Appropriate frequency can be selected. The relative speed can be determined by the size of the contact area between the conductive elastic roller and the image carrier.

The conductive elastic roller is a cored bar covered with a layer made of a conductive elastic member (also simply referred to as a conductive elastic layer or a conductive rubber layer).

Examples of the rubber composition that can be used for the conductive rubber layer include polynorbornene rubber, ethylene-propylene rubber, chloroprene rubber, acrylonitrile rubber, silicone rubber and the like. These rubbers are
It can be used alone or as a mixed rubber of two or more kinds.

In order to impart conductivity, these rubber compositions are mixed with a conductivity-imparting agent and used. Examples of suitable conductivity-imparting agents include known carbon black (furnace-based carbon black or Ketjen black) and metal powder such as tin oxide. The amount of the conductivity imparting agent used is about 5 to 50 parts by mass with respect to 100 parts by mass of the rubber composition.

The rubber composition includes a rubber base material, a foaming agent, and a conductive material.
Chemicals for rubber, rubber additives other than the property-imparting agent
It is also possible to blend to prepare a conductive foam rubber composition.
Rubber chemicals and rubber additives include sulfur and peroxide
Vulcanizing agents such as dough, vulcanization promoting agents such as zinc white, stearic acid, etc.
Agents, sulfenamides, thiurams, thiazoles,
Guanidine-based vulcanization accelerator, amine-based, phenol
-Based, sulfur-based, phosphorus-based anti-aging agents, or antioxidants
Agents, UV absorbers, ozone deterioration inhibitors, tackifiers, etc.
Can be used with various reinforcing agents and friction coefficient adjustment
Agent, silica, talc, inorganic filler such as clay can be selected arbitrarily
Can be selected and used. These conductive rubber layers are 10 ³-10⁷
It is preferable to have a DC volume resistivity in the range of Ω · cm.
Yes.

Further, a releasable coating layer may be provided on the outside of these conductive elastic layers for the purpose of preventing the toner remaining on the surface of the photoreceptor from adhering to the charging member. The coating layer prevents the oil from seeping out from the elastic layer, cancels the resistance unevenness of the elastic layer, and makes the resistance uniform.
It fulfills functions such as protecting the surface of the charging roller and adjusting the hardness of the charging roller. The coating layer may be any layer as long as it satisfies the above physical properties, and may be one layer or a plurality of layers. Examples of the material include resins such as hydrin rubber, urethane rubber, nylon, polyvinylidene fluoride, and polyvinylidene chloride. The thickness of the coating layer is preferably 100 to 1000 μm, and the resistance value is preferably 10 ⁵ to 10 ⁹ Ω · cm. Also,
It is preferable that the resistance value increases as it approaches the surface layer. As a method of adjusting the resistance, it is possible to include a conductive material such as carbon black, metal and metal oxide in the coating layer.

In order to adjust the surface roughness Rz of the charging roller, the surface layer (conductive elastic layer or coating layer) of the charging roller is used.
It is preferable that the powder contains powder. The powder used in the present invention may be either an inorganic substance or an organic substance, but in the case of the inorganic substance, silica powder is particularly preferable. Examples of organic substances include urethane resin particles, nylon particles, silicone rubber particles, and epoxy resin particles. These powders may be used alone or in admixture of two or more. A suitable powder has a surface roughness Rz of the surface layer of 0.05 to 10.0 μm.
It is sufficient to select a substance that can be adjusted to the above range, but if the particle size of the powder is in the range of 1 to 20 μm, the desired surface roughness range can be easily achieved. When the particle size exceeds 20 μm, the surface roughness Rz
Also exceeds 10.0 μm and does not serve the intended purpose. vice versa,
When the particle size is less than 1 μm, the surface roughness Rz is 0.05.
It tends to be less than μm, and this also fails the intended purpose.

The reason why the surface roughness Rz is preferably in the range of 0.05 to 10.0 μm is that when it exceeds 10.0 μm, the toner filming on the roller surface becomes remarkable, and when it is less than 0.05 μm. This is because the adhesion between the charging roller and the photosensitive drum is increased, that is, the contact area is increased, so that the charging noise cannot be suppressed.

The blending ratio of the powder in the surface layer was 100% of resin.
It is preferable to mix and disperse it in a ratio of about 5 to 20 parts by mass with respect to parts by mass.

The charging roller used in the present invention can be manufactured, for example, as follows. That is, first, a metal rotary shaft (core metal) is placed in a mold having a cylindrical molding space, the conductive elastic layer-forming material is filled in the mold, and vulcanization is performed to form the outer circumference of the rotary shaft. A conductive elastic layer is formed on the surface. Then, the rotary shaft on which the conductive elastic layer is formed is taken out from the mold. On the other hand, a material such as urethane resin is mixed with powder, a conductivity-imparting agent and other additives, and the mixture is mixed and stirred using a ball mill or the like to prepare a surface layer forming material mixture. Then, this mixture is applied by a dip method, a roll coating method, a spray coating method or the like on the surface of the rotating shaft on which the conductive elastic layer is formed, dried, and cured by heating to form a two-layer structure. A charging roller can be manufactured.

The surface roughness Rz of the outermost surface layer of the charging roller thus obtained is 0.05 to 1
It is preferably formed to 0.0 μm.

[Development] Next, the developer (toner, carrier) and the developing method used in the present invention will be described.

<< Developer >> The toner used in the present invention is
Although it may be used as a one-component developer or a two-component developer,
A two-component developer is preferred.

In the case of using as a one-component developer, there is a method of using the toner as it is as a non-magnetic one-component developer, but normally, magnetic particles (carriers) of about 0.1 to 5 μm are contained in the toner particles to make it magnetic. Used as a one-component developer. As a method of containing it, it is common to incorporate it in the non-spherical particles in the same manner as the colorant.

Further, it can be used as a two-component developer by mixing with a carrier. In this case, as the carrier magnetic particles, metals such as iron, ferrite and magnetite,
Conventionally known materials such as alloys of these metals with metals such as aluminum and lead are used. Ferrite particles are particularly preferable. The volume average particle diameter of the magnetic particles is 1
The thickness is preferably 5 to 100 μm, more preferably 25 to 60 μm.

The volume average particle diameter of the carrier is typically measured by a laser diffraction type particle size distribution measuring apparatus "HELOS" equipped with a wet disperser (SYMPATIC (SYMP).
(Made by ATEC)).

The carrier is preferably a magnetic particle further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, but for example, an olefin resin, a styrene resin, a styrene-acrylic resin, a silicone resin, an ester resin, a fluorine-containing polymer resin, or the like is used. The resin for forming the resin-dispersed carrier is not particularly limited, and known ones can be used, and for example, styrene acrylic resin, polyester resin, fluorine resin, phenol resin, etc. can be used. it can.

The present inventors can solve the above problem by using a toner in which the variation coefficient of the shape factor of the toner is 16% or less and the number variation coefficient of the number particle size distribution is 27% or less. Found. That is, by making the distribution of the shape of the toner itself uniform, the distribution of the charge amount at the time of transfer can be narrowed, the occurrence of image defects can be prevented, and the image quality can be improved.

Further, as a result of further study by the inventors of the present invention, since toner particles having no corners do not accumulate excessive charging property due to the smoothness of the surface, even if there is a large variation in shape, the same result is obtained. It has been found to be effective. That is, it was found that the problem of the present invention can be solved by using a toner in which the toner particles having no corners are 50 number% or more and the number variation coefficient in the number particle size distribution is 27% or less.

Further, as a result of the study by the present inventors, it was found that even when the shapes of the specific shapes are made uniform, the chargeability of the toner can be made uniform, and the same effect is exhibited. That is, the problem of the present invention is solved by using a toner in which the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more and the variation coefficient of the shape factor is 16% or less. I found that I can.

As a result of studying the distribution of the charge amount of the toner, in order to make the distribution of the charge amount of the toner extremely sharp, the variation in the particle size of the toner particles is controlled to be small and the variation in the shape is also controlled to be small. It turned out to be necessary. By making the toner charge amount distribution extremely sharp, stable chargeability can be obtained for a long period of time even when the toner charge amount is set low, and high image quality can be maintained.

As a result of the examination from the above viewpoints, by using a toner in which the variation coefficient of the shape factor is 16% or less and the number variation coefficient in the number particle size distribution is 27% or less, character dust and color misregistration are obtained. The present inventors have completed the present invention by finding that it is possible to form a high-quality image for a long period of time with no occurrence of the phenomenon.

Further, the inventors of the present invention conducted a study by paying attention to the minute shape of each toner particle, and as a result, inside the developing device, the shape of the corner portion of the toner particle was changed to be round and Was found to cause pollution.
Although the reason for this is not clear, it is presumed that stress is likely to be applied to the corners and the chargeability of the toner is changed. Further, when the electric charge is applied to the toner particles by frictional charging, it is presumed that the electric charge is likely to be concentrated particularly in the corner portions and the electric charge of the toner particles is likely to be non-uniform.

That is, even if the toner particles having no corners are set to 50 number% or more and the number variation coefficient in the number particle size distribution is controlled to 27% or less, a high-quality image free from character dust and color misregistration can be obtained. The inventors have found that they can be formed over a long period of time and have completed the present invention.

Further, it has been found that the charge amount distribution becomes sharp when the toner has a specific shape and the shapes are made uniform. That is, even when toner particles having a shape factor in the range of 1.2 to 1.6 are 65 number% or more and a variation coefficient of the shape factor is 16% or less, character dust and color misregistration are caused. The inventors have found that a high-quality image that does not occur can be formed for a long period of time, and completed the present invention.

The shape factor of the toner of the present invention is represented by the following formula and represents the degree of roundness of toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projected area Here, the maximum diameter means that when a projected image of toner particles on a plane is sandwiched by two parallel lines, It is the width of the particles that maximizes the line spacing. The projected area means the area of the projected image of the toner particles on the plane.

In the present invention, this shape factor is determined by taking a photograph of a toner particle magnified 2000 times with a scanning electron microscope, and then using this photograph, "SCANNING" is taken.
It was measured by analyzing a photographic image using "IMAGE ANALYZER" (manufactured by JEOL Ltd.). At this time, the shape factor of the present invention was measured by the above calculation formula using 100 toner particles.

It is preferable that the number of toner particles having the shape factor in the range of 1.0 to 1.6 is 65% by number or more,
It is more preferably 70% by number or more. More preferably, the number of toner particles having the shape factor in the range of 1.2 to 1.6 is 65% by number or more, and more preferably 70% by number or more.

When the number of toner particles having the shape factor in the range of 1.0 to 1.6 is 65% by number or more, excessively charged toner is not accumulated and problems such as development ghost are less likely to occur. . Further, the toner particles are less likely to be crushed and the chargeability of the toner is stabilized.

The method of controlling the shape factor is not particularly limited. For example, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy due to impact force in a gas phase, or a method of adding a toner to a solvent that does not dissolve toner to give a swirling flow. And the like to prepare a toner having a shape factor of 1.0 to 1.6, or 1.2 to 1.6, and the toner is added to a normal toner so as to fall within the range of the present invention and adjusted. There is a way. Further, the overall shape is controlled at the stage of preparing a so-called polymerization toner, and the shape factor is 1.0 to 1.6,
Alternatively, there is a method of preparing a toner adjusted to 1.2 to 1.6.

Of the above methods, the polymerization toner is preferable because it is simple as a production method, and the surface uniformity is excellent as compared with the pulverized toner.

The variation coefficient of the shape factor of the toner of the present invention is calculated from the following formula. Coefficient of variation = [S / K] × 100 (%) In the formula, S represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor.

The variation coefficient of the shape factor is 16% or less, preferably 14% or less. When the variation coefficient of the shape factor is 16% or less, the voids of the transferred toner layer are reduced, the fixability is improved, and the offset is less likely to occur. In addition, the charge amount distribution becomes sharp and the image quality is improved.

The shape coefficient and the coefficient of variation of the shape coefficient are
In order to control the toner particles (polymer particles) in an extremely uniform and uniform manner, the process of polymerizing, fusing, and controlling the shape of the resin particles is an appropriate process while monitoring the characteristics of the toner particles (coloring particles) that are being formed. You may decide the end time.

Monitoring means that a measuring device is installed in-line and the process conditions are controlled based on the measurement result. That is, by incorporating the measurement of the shape and the like in-line, for example, in the case of a polymerization toner formed by associating or fusing resin particles in an aqueous medium, the shape and the particle shape are measured while performing sequential sampling in the steps such as fusing. The diameter is measured, and the reaction is stopped when the desired shape is obtained.

The monitoring method is not particularly limited, but a flow type particle image analyzer FPIA-
2000 (manufactured by Toa Medical Electronics Co., Ltd.) can be used. This device is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is constantly monitored from the reaction field to measure the shape and the like, and the reaction is stopped when the desired shape or the like is obtained.

The number particle size distribution and the number variation coefficient of the toner are measured with a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Co.). In the present invention, a Coulter Multisizer was used, and an interface (manufactured by Nikkaki Co., Ltd.) for outputting a particle size distribution and a personal computer were connected and used.
The aperture used in the Coulter Multisizer used was 100 μm, and the volume and number of 2 μm or larger toners were measured to calculate the particle size distribution and average particle size. The number particle size distribution represents the relative frequency of toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution.

The number variation coefficient in the number particle size distribution of toner is calculated from the following formula. Number variation coefficient = (S / Dn) × 100 (%) In the formula, S represents the standard deviation in the number particle size distribution, and Dn
Indicates the number average particle diameter (μm).

The number variation coefficient of the toner of the present invention is 27% or less, preferably 25% or less. When the number variation coefficient is 27% or less, the voids of the transferred toner layer are reduced, the fixing property is improved, and the offset hardly occurs. Further, the charge amount distribution becomes sharp, the transfer efficiency is improved, and the image quality is improved.

The method of controlling the number variation coefficient is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for reducing the number variation coefficient. As a method of classifying in this liquid, there is a method of controlling the number of revolutions and separately collecting and preparing toner particles according to the difference in sedimentation speed caused by the difference in toner particle diameter.

Particularly when a toner is produced by the suspension polymerization method, a classification operation is indispensable in order to keep the number variation coefficient in the number particle size distribution at 27% or less. In the suspension polymerization method,
Before the polymerization, it is necessary to disperse the polymerizable monomer into an oil droplet having a desired size as a toner in an aqueous medium. That is, for large oil droplets of the polymerizable monomer, mechanical shearing with a homomixer or a homogenizer is repeated,
Although the oil droplets are reduced to the size of toner particles, the number particle size distribution of the oil droplets obtained by such a mechanical shearing method is wide, and therefore the toner particles formed by polymerizing the oil droplets have a wide particle size distribution. The particle size distribution will also be broad. For this reason, classification operation is essential.

The toner particles having no corners used in the present invention are toner particles having substantially no protrusions on which electric charges are concentrated or protrusions that are easily worn by stress, and specifically, The toner particles are referred to as cornerless toner particles. That is, as shown in FIGS. 5A, 5B, and 5C, a circle having a major axis L of the toner particle and a radius R of L / 10 is in contact with the inner circumference of the toner particle at one point. While rolling inside, when the circle does not substantially protrude outside the toner, the toner particles have no corners. When there is no protrusion, the protrusion with a protruding circle is 1
The following points. The major axis of the toner particles means that when a projected image of the toner particles on a plane is sandwiched by two parallel lines,
It is the width of the particles at which the distance between the parallel lines is maximum.

The toner having no corners was measured as follows. First, an enlarged photograph of toner particles is taken with a scanning electron microscope and further enlarged to obtain a photographic image at 15,000 times. Then, the presence or absence of the above-mentioned corner is measured for this photographic image. This measurement was performed on 100 toner particles.

In the toner of the present invention, the proportion of toner particles having no corners is 50% by number or more, preferably 70% by number or more. When the proportion of the toner particles having no corners is 50% by number or more, the generation of fine particles is less likely to occur due to the stress with the developer conveying member and the like, and the toner has excessive adhesion to the surface of the developer conveying member. Can be prevented, contamination of the developer carrying member can be suppressed, and the charge amount can be sharpened. Further, the toner particles that are easily worn or broken and the toner particles having a portion where electric charge is concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed for a long time.

The method for obtaining the toner without corners is not particularly limited. For example, as described above as a method of controlling the shape factor, a method of spraying toner particles in a hot air flow, a method of repeatedly applying mechanical energy due to impact force in a gas phase, or a method of dissolving toner It can be obtained by adding it to a solvent that does not contain it and imparting a swirling flow.

Further, in the polymerization toner formed by associating or fusing the resin particles, the surface of the fused particles has many irregularities at the step of stopping the fusion, and the surface is not smooth. By adjusting the conditions such as the temperature, the number of revolutions of the stirring blade, and the stirring time, toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles, but, for example, at a glass transition temperature of the resin particles or higher, by setting a higher rotation speed,
The surface is smooth, and toner without corners can be formed.

The toner used in the present invention preferably has a number average particle diameter of 3 to 8 μm. This particle size is
When the toner particles are formed by the polymerization method, it can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and the composition of the polymer itself.

By having the number average particle diameter of 3 to 8 μm, it is possible to reduce the presence of excessively adherent toner or toner having low adherence to the developer conveying member in the fixing step, and to improve the developability. It is possible to stabilize for a long period of time, the transfer efficiency is improved, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

The toner used in the present invention has a natural logarithm lnD when the particle diameter of the toner particles is D (μm).
In the histogram showing the number-based particle size distribution in which the horizontal axis is divided into a plurality of classes at intervals of 0.23, the relative frequency (m1) of the toner particles included in the most frequent class
And the sum (M) of the relative frequency (m2) of the toner particles included in the most frequent class next to the most frequent class is 70% or more. Since the sum (M) of the relative frequency (m1) and the relative frequency (m2) is 70% or more, the dispersion of the particle size distribution of the toner particles becomes narrow,
By using the toner in the image forming process, it is possible to reliably suppress the occurrence of selective development.

In the present invention, the histogram showing the number-based particle size distribution has a natural logarithm lnD (D: particle size of individual toner particles) in a plurality of classes (0 to 0) at intervals of 0.23.
0.23: 0.23 to 0.46: 0.46 to 0.69:
0.69 to 0.92: 0.92 to 1.15: 1.15
1.38: 1.38 to 1.61: 1.61 to 1.84:
1.84-2.07: 2.07-2.30: 2.30-
2.53: 2.53 to 2.76 ...), which is a histogram showing a number-based particle size distribution, and the histogram shows particle size data of a sample measured by a Coulter Multisizer according to the following conditions. Is transferred to a computer via an I / O unit and is created by the particle size distribution analysis program in the computer.

Measurement conditions (1) Aperture: 100 μm (2) Sample preparation method: Electrolyte solution [ISOTON R-1
1 (manufactured by Coulter Scientific Japan)
An appropriate amount of a surfactant (neutral detergent) is added to 50 to 100 ml and stirred, and 10 to 20 mg of a measurement sample is added thereto. This system is prepared by subjecting it to an ultrasonic disperser for 1 minute.

Next, regarding the numerical values relating to the present invention, the numerical values of the conventionally known toner will be described. This value depends on the manufacturing method.

For the pulverized toner, the shape factor is 1.2 to
The ratio of toner particles having a particle size of 1.6 is about 60% by number. The variation coefficient of the shape factor of this product is about 20%. Further, in the pulverization method, since the particle size is reduced while repeating crushing, the toner particles have many corners, and the ratio of toner particles having no corners is 30 number% or less. Therefore,
In order to obtain a toner having a rounded shape with the same shape without corners, it is necessary to heat the particles to make them spherical as a method of controlling the shape coefficient. Further, the number variation coefficient in the number particle size distribution is about 30% when the classification operation after crushing is performed once, and further the classification operation needs to be repeated in order to reduce the number variation coefficient to 27% or less. There is.

In the case of the toner by the suspension polymerization method, since the toner is polymerized in a laminar flow conventionally, almost spherical toner particles can be obtained. For example, in the toner described in JP-A-56-130762, The ratio of toner particles having a coefficient of 1.2 to 1.6 is about 20% by number, the variation coefficient of the shape coefficient is about 18%, and the ratio of toner particles without corners is about 85% by number. Further, as described above in the method of controlling the number variation coefficient in the number particle size distribution,
Mechanically shearing large oil droplets of polymerizable monomers to reduce the oil droplets to the size of toner particles, so the oil droplet size distribution becomes wider, and the resulting toner particle size distribution Is large, and the number variation coefficient is as large as about 32%, and in order to reduce the number variation coefficient, classification operation is necessary if toner is produced based on the technique described in the above-mentioned Japanese Patent Laid-Open Publication No. Sho.

A polymerization toner formed by associating or fusing resin particles is described in, for example, JP-A-63 / 1988.
In the toner described in JP-A-186253, the ratio of toner particles having a shape factor of 1.2 to 1.6 is about 60% by number, the variation coefficient of the shape factor is about 18%, and The ratio of toner particles not present is also about 44% by number. Further, the particle size distribution of the toner is wide, and the number variation coefficient is 30%, and classification operation is required to reduce the number variation coefficient.

The toner used in the present invention is produced by a suspension polymerization method or emulsion polymerization of a monomer in a liquid containing an emulsion of necessary additives to produce fine polymer particles. It can be manufactured by a method in which an organic solvent, a flocculant, etc. are added and associated. At the time of association, a method of preparing by mixing with a dispersion liquid such as a release agent or a colorant necessary for the constitution of the toner and causing association, or dispersing a toner constituent component such as the release agent or the colorant in a monomer Then, a method of emulsion polymerization may be used. Here, the association means that a plurality of resin particles and colorant particles are fused.

The aqueous medium in the present invention means a medium containing at least 50% by mass of water.

That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, and an ultrasonic dispersion are added. Various constituent materials are dissolved or dispersed in the polymerizable monomer by a machine or the like. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in an oil droplet having a desired size as a toner in a water-based medium containing a dispersion stabilizer using a homomixer, a homogenizer or the like. Then, the stirring mechanism is transferred to a reaction device which is a stirring blade described later and heated to allow the polymerization reaction to proceed. After the completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare a toner.

As a method for producing the toner used in the present invention, there may be mentioned a method in which resin particles are associated or fused in an aqueous medium to prepare. This method is not particularly limited, but, for example, Japanese Patent Laid-Open No.
-265252, 6-329947, 9-15
The method shown in No. 904 can be mentioned.

A method of associating a plurality of resin particles and dispersed particles of a constituent material such as a colorant or fine particles composed of a resin and a colorant with each other, particularly after dispersing them in water using an emulsifier, and then performing critical coagulation At the same time as adding a coagulant at a concentration higher than that for salting out, heat-bonding is performed at a temperature not lower than the glass transition temperature of the formed polymer itself to gradually grow the particle size while forming fused particles, and to obtain the target particle size. At this point, a large amount of water is added to stop the particle size growth, and the particle surface is smoothed while heating and stirring to control the shape, and by heating and drying the particles in a fluid state in a water-containing state, The toner used in the present invention can be formed. Here, an organic solvent that is infinitely soluble in water may be added simultaneously with the coagulant.

The polymerizable monomer used for the resin is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4- Dichlorostyrene,
p-phenylstyrene, p-ethylstyrene, 2,4-
Dimethyl styrene, p-tert-butyl styrene, p
-N-hexyl styrene, pn-octyl styrene,
pn-nonylstyrene, pn-decylstyrene, p
Styrene or styrene derivative such as -n-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, methacrylic acid 2 -Methacrylic acid ester derivatives such as ethylhexyl, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid n
-Butyl, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate,
Acrylic ester derivatives such as phenyl acrylate, olefins such as ethylene, propylene and isobutylene,
Halogen-based vinyls such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride and vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate and vinyl benzoate, vinyl ethers such as vinyl methyl ether and vinyl ethyl ether. Vinyl vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone, vinyl compounds such as vinyl naphthalene and vinyl pyridine, There are acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide. These vinyl monomers can be used alone or in combination.

Further, it is more preferable to use a combination of those having an ionic dissociative group as the polymerizable monomer constituting the resin. For example, those having a substituent such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as a constituent group of the monomer, and specifically, acrylic acid, methacrylic acid,
Maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrenesulfonic acid, allylsulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphooxyethyl Methacrylate,
3-chloro-2-acid phosphooxypropyl methacrylate and the like can be mentioned.

Further, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use the above polyfunctional vinyls as a resin having a crosslinked structure.

These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. As this oil-soluble polymerization initiator, 2,2'-azobis- (2,4
-Dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo-based or diazo-based polymerization initiators such as nitrile and azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide. , Dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis-
Examples thereof include peroxide polymerization initiators such as (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine, and polymer initiators having a peroxide in the side chain. .

When the emulsion polymerization method is used, a water-soluble radical polymerization initiator can be used. As the water-soluble radical polymerization initiator, potassium persulfate, persulfate such as ammonium persulfate, azobisaminodipropane acetate,
Azobis cyanovaleric acid and its salt, hydrogen peroxide, etc. can be mentioned.

Examples of the dispersion stabilizer include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate. , Barium sulfate,
Examples thereof include bentonite, silica and alumina. Furthermore, polyvinyl alcohol, gelatin, methyl cellulose, sodium dodecylbenzene sulfonate, ethylene oxide adduct, higher alcohol sodium sulfate, and the like which are commonly used as surfactants can be used as the dispersion stabilizer.

The resin excellent in the present invention preferably has a glass transition point of 20 to 90 ° C. and a softening point of 8
It is preferably 0 to 220 ° C. The glass transition point is measured by a differential calorimetric method, and the softening point can be measured by a Koka type flow tester. Furthermore, these resins have a number average molecular weight (Mn) of 10 as measured by gel permeation chromatography.
00-100,000, 200 in mass average molecular weight (Mw)
It is preferably 0 to 1,000,000. Furthermore, as the molecular weight distribution, Mw / Mn is 1.5 to 100, and particularly 1.8.
The thing of -70 is preferable.

The aggregating agent used is not particularly limited, but those selected from metal salts are preferably used. Specifically, examples of monovalent metals include salts of alkali metals such as sodium, potassium and lithium, examples of examples of divalent metals include alkaline earth metal salts such as calcium and magnesium, and divalent metals such as manganese and copper. And salts of trivalent metals such as iron and aluminum. Specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, and sulfuric acid. Manganese etc. can be mentioned. These may be used in combination.

The toner used in the present invention contains at least a resin and a colorant, but may contain a releasing agent which is a fixing property improving agent, a charge control agent and the like, if necessary. Further, an external additive composed of inorganic fine particles, organic fine particles or the like may be added to the toner particles containing the resin and the colorant as main components.

The colorant used in the toner used in the present invention may be any carbon black, magnetic substance, dye, pigment or the like. Examples of carbon black are channel black, furnace black, acetylene black and thermal black. , Lamp black, etc. are used. As the magnetic substance, iron, nickel, ferromagnetic metals such as cobalt, alloys containing these metals, ferrite, compounds of ferromagnetic metals such as magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example,
Alloys of the type called Heusler alloys such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide and the like can be used.

As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 1
22, C.I. I. Solvent Yellow 19, 44, 7
7, ibid 79, ibid 81, ibid 82, ibid 93, ibid 98, ibid 10
3, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 9
5 and the like can be used, and a mixture thereof can also be used. As the pigment, C.I. I. Pigment Red 5, Same 48: 1, Same 53: 1, Same 57: 1, Same 122,
139, 144, 149, 166, 177,
178, 222, C.I. I. Pigment Orange 3
1, 43, C.I. I. Pigment Yellow 14 and 1
7, ibid 93, ibid 94, ibid 138, C.I. I. Pigment Green 7, C.I. I. Pigment Blue 15: 3, 60
Etc. can be used, and a mixture thereof can also be used. The number average primary particle size varies depending on the type,
About 10 to 200 nm is preferable.

The colorant may be added by adding the polymer particles prepared by the emulsion polymerization method at the stage of aggregating by adding an aggregating agent to color the polymer or at the step of polymerizing a monomer. It is possible to use a method in which a coloring agent is added and polymerized to obtain colored particles. When the colorant is added at the stage of preparing the polymer, it is preferable that the surface is treated with a coupling agent or the like so as not to hinder radical polymerizability.

Further, low molecular weight polypropylene (number average molecular weight = 1500 to 9000) or low molecular weight polyethylene as a fixability improving agent may be added.

Similarly, the charge control agents are various known ones,
Moreover, the thing which can be disperse | distributed in water can be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines,
Examples thereof include secondary ammonium salt compounds, azo-based metal complexes, salicylic acid metal salts or metal complexes thereof. The particles of these charge control agents and fixability improvers preferably have a number average primary particle diameter of about 10 to 500 nm in a dispersed state.

A suspension polymerization method toner in which a toner component such as a colorant or the like is dispersed or dissolved in a so-called polymerizable monomer is suspended in an aqueous medium and then polymerized to obtain a toner is subjected to a polymerization reaction. The shape of the toner particles can be controlled by controlling the flow of the medium in the reaction vessel. That is, when a large number of toner particles having a shape factor of 1.2 or more are formed, the flow of the medium in the reaction vessel is made turbulent, and the polymerization proceeds to exist in the aqueous medium in a suspended state. When the oil droplets gradually become polymerized and become soft particles, the particles collide with each other to promote coalescence of the particles, and particles with an irregular shape are obtained. . When spherical toner particles having a shape factor of less than 1.2 are formed, spherical particles can be obtained by avoiding collision of particles by making the flow of the medium in the reaction vessel a laminar flow. By this method, the distribution of toner shape can be controlled within the range of the present invention.

In the suspension polymerization method, turbulent flow can be formed and the shape can be easily controlled by using a specific stirring blade.

On the other hand, in the case of the polymerized toner in which the resin particles are associated or fused with each other in the aqueous medium, the flow and temperature distribution of the medium in the reaction vessel at the fusion stage are controlled to further improve the shape after fusion. By controlling the heating temperature, the stirring rotation number, and the time in the control step, the shape distribution and shape of the entire toner can be arbitrarily changed.

In the polymerization method toner in which resin particles are associated or fused, a flow in the reaction device is made a laminar flow, and a fusing step using a stirring blade and a stirring tank capable of making the temperature distribution inside the reactor uniform. By controlling the temperature, the number of rotations, and the time in the shape control step, it is possible to form the toner having the shape factor and the uniform shape distribution of the present invention.

Further, in the toner used in the present invention, the effect can be more effectively exhibited by adding fine particles such as inorganic fine particles and organic fine particles as an external additive. The reason for this is presumed to be that the embedding and detachment of the external additive can be effectively suppressed, and the effect is remarkable.

As the inorganic fine particles, it is preferable to use inorganic oxide particles such as silica, titania, and alumina. Further, these inorganic fine particles are hydrophobized with a silane coupling agent or a titanium coupling agent. preferable.

The amount of the external additive added is 0.1 to 5.0% by mass, preferably 0.5 to 4.0% by mass in the toner. Further, various external additives may be used in combination.

<< Developing Method >> The developing method can be used either in contact or in non-contact. When a non-contact developing method is adopted, non-contact regular development or non-contact reversal development can be carried out. The direct current developing electric field at that time is 1 × 10 ³ to 1 × 10 ⁵ V / cm in absolute value, preferably 5 × 10 ³
Is a ^{~1 × 10 4 V / cm,} 10 3 and development is less than V / cm is insufficient, no sufficient image density is obtained, 10 ⁵ V / c
If it exceeds m, the image quality is deteriorated and fogging occurs.

The AC bias is 0.5 to 4 kVp-p, preferably 1 to 3 kVp-p, and the frequency is 0.1.
It is set to 10 kHz, preferably 2 to 8 kHz. When the AC bias is less than 0.5 kVp-p, the toner adhering to the carrier does not separate, and the non-contact development becomes insufficient,
Image density is insufficient. The AC bias is 4 kVp-p.
When it exceeds the range, the carrier in the developer flies and the carrier adheres to the photoreceptor. Further, the frequency of the AC bias is 0.
If it is less than 1 kHz, the toner is not sufficiently detached from the carrier, resulting in insufficient development and a decrease in image density. Further, if the frequency of the AC bias exceeds 10 kHz, the toner cannot follow the fluctuation of the electric field, resulting in poor development and a decrease in image density.

Next, the image forming apparatus of the present invention will be described. [Image Forming Apparatus] FIG. 6 is a diagram showing an example of an image forming apparatus that performs roller charging. This image forming apparatus is for carrying out the present invention, and a charging roller is contacted with a photosensitive drum to form an electrostatic latent image so as to be charged, and a transfer roller is used for transferring toner to a transfer paper. In this embodiment, the so-called contact charging method is adopted in which the generation of ozone is avoided by bringing this transfer roller into contact with the photoconductor drum directly or with a transfer paper sandwiched therebetween, and the so-called contact charging method is adopted. It develops an electrostatic latent image.

In FIG. 6A, an electrostatic latent image is formed on the photosensitive drum 1 charged by the charging roller 2.
Then, this electrostatic latent image is developed into a toner image by the developing sleeve 17 which is a developer carrying member of the developing device 4 which is arranged close to the photosensitive drum 1. Then, after the charge of the photoconductor drum 1 is removed by the pre-transfer charge eliminating lamp 18, the toner image is transferred to the transfer sheet P conveyed by the conveying roller 7 from the sheet feeding cassette, and has a polarity opposite to that of the toner by the transfer roller 8. Is applied, and the toner is transferred to the transfer paper P by the electrostatic force of the charges of the opposite polarity. The transfer paper P after the toner transfer is separated from the photoconductor drum 1 and then sent to the fixing device by the conveyor belt 19, and the toner image is fixed on the transfer paper P by the heating roller and the pressing roller.

A bias voltage composed of DC and AC components is applied to the charging roller 2 (and the transfer roller 8) from the high voltage power source 13 (20), and the charging and charging of the photosensitive drum 1 is performed in a state where the ozone generation amount is extremely small. The toner image is transferred to the transfer paper P. The bias voltage is usually ± 500 to 1
DC bias of 000V and superimposed on this, 100Hz-
It consists of an AC bias of 200 kHz to 3500 Vp-p at 10 kHz.

The charging roller 2 and the transfer roller 8 are driven or forcedly rotated while being pressed against the photosensitive drum 1.

The pressure contact with the photosensitive drum 1 is 100 to 1
The rotation speed of the roller is 1 to 8 times the peripheral speed of the photosensitive drum 1.

As shown in FIG. 6B, the charging roller 2 (and the transfer roller 8) includes a conductive core metal 2a and conductive elastic members such as chloroprene rubber, urethane rubber, and silicone rubber provided on the outer periphery thereof. And a conductive layer 2b made of a sponge layer thereof, and preferably a protective layer 2c made of a release fluorine-containing resin or silicone resin layer having a thickness of 0.01 to 1 μm is provided on the outermost layer. It

After the transfer, the photosensitive drum 1 is cleaned by pressure contact with the cleaning blade 21 of the cleaning device 12, and is ready for the next image formation.

The electrophotographic image forming apparatus is constituted by integrally combining a photosensitive member, a developing device, a cleaning device and the like as a process cartridge, and this unit is configured to be detachable from the apparatus main body. Good. Further, at least one of the image exposure device, the developing device, the transfer or separator, and the cleaning device is integrally supported together with the photoconductor to form a process cartridge, which is a detachable single unit in the device body, such as a rail of the device body. The guide means may be used to make it detachable.

Although the transfer roller is used for the transfer in FIG. 6, a transfer means other than the transfer roller may be used in the present invention.

<< Magnetic Particles >> Next, the magnetic particles (carriers) forming the magnetic brush for charging will be described.

FIG. 7 is a block diagram of a contact type magnetic brush charging device, and FIG. 8 is a diagram showing the relationship between the AC bias voltage and the charging potential by the charging device of FIG.

Generally, when the volume average particle diameter of the magnetic particles forming the magnetic brush for charging is large, the state of the ears of the magnetic brush formed on the carrier (carrier) for charging magnetic particles is rough, so that the electric field is generated. Even when charged while vibrating, unevenness is likely to appear on the magnetic brush, which causes a problem of uneven charging.
In order to solve this problem, the volume average particle diameter of the magnetic particles should be reduced. As a result of the experiment, the volume average particle diameter is 200 μm.
When the thickness is m or less, the effect begins to appear, and particularly when it is 150 μm or less, the problem associated with the coarseness of the ears of the magnetic brush does not substantially occur. However, if the particles are too fine, they tend to adhere to the surface of the photoconductor drum at the time of charging, or easily scatter. These phenomena are related to the strength of the magnetic field acting on the particles and the strength of the magnetization of the particles thereby, but generally, the volume average particle diameter of the particles becomes prominent at 20 μm or less.

From the above, the particle size of the magnetic particles is the volume average particle size.
Is 20 to 200 μm, and the number average particle of magnetic particles is
30% by number of magnetic particles having a diameter less than 1/2 times the diameter
The following is preferable. The strength of magnetization is 3.7.
5 x 10^-Five~ 12.5 x 10 ^-FiveWb · m / kg
It is preferably used.

Such a magnetic particle is a metal such as iron, chromium, nickel, cobalt or the like, or a compound or alloy thereof, similar to the magnetic carrier particle of the conventional two-component developer described above as a magnetic substance, for example, Ferric oxide, γ-
Ferromagnetic particles such as ferric oxide, chromium dioxide, manganese oxide, ferrite, and manganese-copper alloy, or the surfaces of these magnetic particles are styrene resin, vinyl resin, ethylene resin, rosin-modified resin, acrylic. Particles obtained by coating with a resin such as a system resin, a polyamide resin, an epoxy resin, or a polyester resin, or by a resin containing magnetic fine particles dispersed therein are obtained by a conventionally known average particle size selection means. It is obtained by selecting the particle size.

It should be noted that forming the magnetic particles spherically
The particle layer formed on the carrier is made uniform, and a high bias voltage can be uniformly applied to the carrier. That is, the fact that the magnetic particles are spherical means that (1) generally, the magnetic particles are easily magnetized and adsorbed in the long-axis direction, but due to the spherical shape, the directionality is lost, so that the magnetic particle layer is uniformly formed, (2) Higher resistance of magnetic particles is eliminated along with the increase in the resistance of magnetic particles, which eliminates the edge parts seen in conventional particles and concentrates the electric field on the edge parts. As a result, even if a high bias voltage is applied to the carrier for carrying the magnetic particles for charging, it is possible to uniformly discharge the surface of the photoconductor drum and prevent uneven charging.

As the spherical particles having the above effects, conductive particles are preferably formed so that the magnetic particles have a resistivity of 10 ⁵ to 10 ¹⁰ Ω · cm. This resistivity is 10 N / c on the packed particles after tapping the particles in a container with a cross-sectional area of 0.50 cm ^2.
Apply a load of m ² and 1000 V between the load and the bottom electrode.
Is a value obtained by reading the current value when a voltage that generates an electric field of / cm is applied. If this resistivity is low,
When a bias voltage is applied to the carrier, electric charges are injected into the magnetic particles and the magnetic particles easily adhere to the surface of the photoconductor drum, or the dielectric breakdown of the photoconductor drum due to the bias voltage easily occurs. . If the resistivity is high, charge injection is not performed and charging is not performed.

Further, the contact type magnetic brush charging device 120
It is desirable that the magnetic particles used in (1) have a small specific gravity and have an appropriate maximum magnetization so that the magnetic brush constituted by them can move lightly due to an oscillating electric field, and that external scattering does not occur. Specifically, the true specific gravity is 6 or less, and the maximum magnetization is 3.75 × 10 ^{−5 to} 12.5 × 10 ⁻⁵ Wb · m /
kg, especially 4.73 × 10 ^{-5 to} 9.47 × 10 ^-5
It was found that good results can be obtained by using Wb · m / kg.

In summary, the magnetic particles are spherical so that at least the ratio of the major axis to the minor axis is 3 times or less, there is no protrusion such as a needle-shaped portion or an edge portion, and the resistivity is It is preferably in the range of 10 ⁵ to 10 ¹⁰ Ω · cm. Then, such spherical magnetic particles should be selected as spherical as possible for the magnetic particles, and in the particles of the magnetic material fine particle dispersion system, the fine particles of the magnetic material should be used as much as possible, and the spheroidizing treatment should be performed after the formation of the dispersed resin particles. It is manufactured by applying or by forming dispersed resin particles by a spray drying method.

According to FIG. 7, the magnetic brush charging device 120 as a charging device is (1) facing the rotating photosensitive drum 1 and in the same direction (charging portion T) in the vicinity of the photosensitive drum 1 (charging portion T). A cylindrical charging sleeve 120a made of, for example, an aluminum material or a stainless material, which serves as a charging magnetic particle carrier rotated in a counterclockwise direction, and (2) N and S provided inside the charging sleeve 120a. The charging sleeve 12 is composed of the magnet body 121 including the poles and (3) the magnet body 121.
0a, a magnetic brush formed of magnetic particles for charging the photosensitive drum 1 and (4) N of the magnet body 121.
A scraper 123 for scraping off the magnetic brush on the charging sleeve 120a at the −N magnetic pole part, and (5) stirring the magnetic particles in the magnetic brush charging device 120 or discharging used magnetic particles from the magnetic brush charging device 120 when supplying the magnetic particles. Stirring screw 124 overflowing and discharging from outlet 125
And (6) the spike-up regulating plate 126 of the magnetic brush. The above charging roller is the charging sleeve 120a.
And a magnet body 121 provided therein.

The charging sleeve 120a is rotatable with respect to the magnet body 121, and is 0.1 to 1 in the same direction (counterclockwise direction) as the moving direction of the photosensitive drum 1 at the position facing the photosensitive drum 1. It is preferably rotated at a peripheral speed of 0.0 times. The charging sleeve 120a uses a conductive carrier that can apply a charging bias voltage, and in particular, a conductive charging sleeve 120a having a particle layer formed on the surface thereof.
A structure having a magnet body 121 having a plurality of magnetic poles inside is preferably used. In such a carrier, the magnetic particle layer formed on the surface of the conductive charging sleeve 120a moves in a wavy shape due to the relative rotation with the magnet body 121.
The charging sleeve 120 is supplied with new magnetic particles one after another.
a Even if the magnetic particle layer on the surface has some non-uniformity in layer thickness,
The effect is well covered by the above-mentioned wavy undulations so that it is practically no problem. The surface of the charging sleeve 120a preferably has an average surface roughness of 5.0 to 30 μm for stable and uniform transfer of magnetic particles. If the surface is smooth, the transfer cannot be performed sufficiently, and if it is too rough, the surface has a convex shape. Overcurrent flows from the part, and uneven charging is likely to occur in either case. To achieve the above surface roughness, sandblast treatment is preferably used. The outer diameter of the charging sleeve 120a is 5.0.
-20 mm is preferable. This ensures the contact area required for charging. If the contact area is unnecessarily large, the charging current will be excessive, and if it is small, uneven charging is likely to occur. When the diameter is small as described above, magnetic particles are easily scattered or adhered to the photoconductor drum 1 due to centrifugal force. Therefore, the linear velocity of the charging sleeve 120a is almost the same as the moving velocity of the photoconductor drum 1, or more than that. Is also preferably slow.

Further, the thickness of the magnetic particle layer formed on the charging sleeve 120a is preferably such that it is sufficiently scraped off by the regulating means to form a uniform layer. If the amount of magnetic particles present on the surface of the charging sleeve 120a is too large in the charging region, the magnetic particles are not sufficiently vibrated, causing wear and uneven charging of the photoconductor, and an overcurrent is likely to flow, resulting in a driving torque of the charging sleeve 120a. Has the drawback of becoming large. On the contrary, if the amount of the magnetic particles present on the charging sleeve 120a in the charging area is too small, an incomplete portion may be formed in contact with the photoconductor drum 1, and the magnetic particles may adhere to the photoconductor drum 1 or cause uneven charging. become. As a result of repeated experiments, it has been found that the preferable adhesion amount of the magnetic particles in the charged region is 100 to 400 mg / cm ² , and particularly preferably 200 to 300 mg / cm ² . The amount of adhesion is an average value in the charged area of the magnetic brush.

Magnetic Brush Charging Device 12 as Charging Device
0 is a charging bias in which an alternating current (AC) bias AC3 is superimposed on the direct current (DC) bias E3 if necessary, for example, −100 to − of the same polarity as the toner (negative polarity in the present embodiment) as the direct current bias E3. 500V
However, the frequency of AC bias AC3 is 1 to 5 kHz.
z, peak-peak voltage (Vp-p) 300 to 500V
The peripheral surface of the photosensitive drum 1 is brought into contact with and rubbed by the charging sleeve 120a to which the charging bias of 1 is applied, so that the photosensitive drum 1 is charged. Since an oscillating electric field is formed between the charging sleeve 120a and the photosensitive drum 1 by the voltage application of the AC bias AC3, the charge is smoothly injected onto the photosensitive layer through the magnetic brush. Thus, high-speed charging is performed.

Charging sleeve 1 in which the photosensitive drum 1 is charged
The magnetic brush on 20a is N provided on the magnet body 121.
In the −N magnetic pole part, the magnetic brush is stirred by the stirring screw 124 that is dropped from the charging sleeve 120a by the scraper 123 and rotates in the opposite direction (counterclockwise) to the charging sleeve 120a in the vicinity of the charging sleeve 120a. It is formed and conveyed to the charging section T.

As shown in FIG. 8, the relationship between the peak-peak voltage (Vp-p) of the AC bias AC3 of the charging bias and the charging potential is that the charging potential increases as the peak-peak voltage increases, and the charging potential increases. Has a characteristic that when the peak-peak voltage is constant V1, it is saturated at a value almost equal to the value VS of the DC bias E3 of the charging bias, and the charging potential hardly changes even if the peak-peak voltage is further increased. Although the electric resistance of the magnetic particles changes depending on the environmental conditions, the electric resistance increases as the toner is fused to the surface of the magnetic particles as it is used. Therefore, the characteristic curve is shown on the left side as shown by a solid line in the case of new magnetic particles in the initial stage of use, and on the right side as shown by a dotted line in the case of magnetic particles used for a long time as shown in (b). Will be located in.

In the contact type charging device of the image forming apparatus of the present invention, the voltage value of the DC bias E3 corresponding to the charging potential is set to a predetermined value when the mounting power source is turned on or before printing is started, and the peak / peak of the AC bias AC3 is set. A charging bias in which the voltage is gradually increased from a low value is applied, and the charging potential of the photosensitive drum 1 which changes at that time is detected by the electrometer ES. The detected charging potential is converted into a digital value by the A / D converter and then input to the control unit (CPU). In the control section, the value of the peak-peak voltage when the charging potential reaches the saturation point of the predetermined value VS is defined as the proper bias value V1 and the printing operation is performed.

That is, when printing is performed, the AC bias AC3 is gradually increased (swept) from a low value.
The value V1 of the peak-to-peak voltage of the AC bias AC3 is obtained, and the bias signal is output from the control unit. After this control signal is converted into an analog value by the D / A converter,
The AC bias AC3 is sent to the AC bias AC3, and the AC bias AC3 outputs the determined peak-to-peak voltage V1. The peak-peak voltage V1 at that time and the specified value V2 to be exchanged due to the deterioration of the magnetic particles stored in the memory are read out and compared with this. Since the resistance of the magnetic particles increases due to the mixing of toner, an appropriate bias value V1 is set according to the use of printing.
Will increase. Along with this, the peak-to-peak voltage applied increases, and an unchargeable state occurs. While the image formation is continued while the measured voltage value is smaller than the specified value V2 indicating that charging is impossible, when the measured voltage value is larger than the specified value V2, the image forming operation stop signal is sent from the control unit to stop the image forming operation, and not shown. The abnormality of the charging device is displayed on the display of the operation unit. Based on this display, the supply bottle 220 of the magnetic particles for charging is set in the magnetic brush charging device 120, and an opening / closing lid (not shown) on the bottom of the supply bottle 220 is opened to drop and supply the magnetic particles to the magnetic brush charging device 120. To do. In the above, the electrometer ES was used to measure the potential of the photosensitive drum 1, but a peak current was measured using a DC ammeter connected to the bias power source.
By changing the peak voltage and setting the peak-peak voltage when this current value reaches the saturation point as the proper bias value V1,
It is also possible to compare with a specified value V2 and supply the magnetic particles when V1 is exceeded.

Further, the magnetic particles for charging are exchanged at the time of maintenance or at regular intervals such as 50,000 prints. For each maintenance print stored in memory,
For example, at a regular interval of every 50,000 prints, an exchange signal is output through the control unit, and the supply roller 221 of the supply bottle 220 of the magnetic particles for charging, which is set in advance by the drive of the drive motor (not shown), is rotated to supply the supply bottle 220. All of the magnetic particles therein are dropped into the magnetic brush charging device 120 at one time. After the supply, it is also possible to remove the empty supply bottle 220 and set a new supply bottle 220 to control the image forming apparatus to the operating state. In addition, at the time of periodical operation, the control unit displays a supply signal, such as a blinking lamp, on the operation unit (not shown) so that the supply bottle 220
Set in the magnetic brush charging device 120, and supply bottle 2
An opening / closing lid (not shown) on the bottom surface of 20 may be opened to supply the magnetic particles.

The dropped magnetic particles are conveyed by the rotating charging sleeve 120a, scraped off the surface of the charging sleeve 120a by the scraper 123, and supplied to the bottom of the magnetic brush charging device 120. Along with this, the used magnetic particles stored in the magnetic brush charging device 120 are overflowed from the discharge port 125 by the stirring screw 124 rotated counterclockwise, and the common magnetic particle recovery container 300 is passed through the duct DB. Will be collected. At this time, the amount of magnetic particles supplied from the supply bottle 220 into the magnetic brush charging device 120 once is 20 to 5 with respect to all the magnetic particles stored in the magnetic brush charging device 120.
0 mass% is preferable. If the amount is less than 20% by mass, the amount of newly supplied magnetic particles is too small to have an exchange effect and good charging cannot be performed. If the amount exceeds 50% by mass, new magnetic particles overflow.

As described above, good charging performance is maintained for a long period of time without deteriorating the magnetic particles in the charging device.

FIG. 9 is a sectional view showing an example of an image forming apparatus having the magnetic brush charging device of the present invention. In FIG. 9, reference numeral 1 denotes a photoconductor drum (photoconductor) which is an image carrier, and is a photoconductor in which an organic photosensitive layer is coated on the drum, and the siloxane resin layer of the present invention is coated on the drum, which is grounded. It is driven and rotated clockwise. Reference numeral 120 denotes a magnetic brush charging device, which uniformly charges the peripheral surface of the photosensitive drum 1. Prior to the charging by the magnetic brush charging device 120, in order to eliminate the history of the photosensitive member in the previous image formation, the exposure unit 51 using a light emitting diode or the like may perform exposure to remove the charge on the peripheral surface of the photosensitive member.

After uniformly charging the photosensitive member, the image exposure device 53 performs image exposure based on the image signal. The image exposure device 53 in this figure uses a laser diode (not shown) as an exposure light source. The photosensitive drum is scanned by the light whose optical path is bent by the reflecting mirror 532 through the rotating polygon mirror 531, the fθ lens, etc., and an electrostatic latent image is formed.

The electrostatic latent image is then developed by the developing device 4. A developing device 4 containing a developer composed of toner and carrier is provided on the periphery of the photosensitive drum 1.
Development is carried out by a developing sleeve 17 which contains a magnet and holds a developer and rotates. The developer is, for example,
A carrier coated with an insulating resin around the ferrite core as a core, colored particles composed of a coloring agent such as carbon black and a charge control agent and a low molecular weight polyolefin mainly composed of the styrene acrylic resin, silica, silica, The toner is a toner to which titanium oxide or the like is added, and the developer is regulated to a layer thickness of 100 to 600 μm on the developing sleeve 17 by a layer forming means (not shown) and conveyed to the developing area for development. . At this time, normally, a DC bias is applied between the photoconductor drum 1 and the developing sleeve 17, and an AC bias voltage is applied as necessary to perform development.
Further, the developer is developed in a state of being in contact with or non-contacting with the photoreceptor.

The transfer material (also referred to as recording paper) P is fed to the transfer area by the rotation operation of the conveying roller 7 when the transfer timing is adjusted after the image formation.

In the transfer area, the transfer roller 8 is pressed against the peripheral surface of the photosensitive drum 1 in synchronization with the transfer timing.
The transferred transfer material P is sandwiched and transferred.

Then, the transfer material P is destaticized by the separating brush 59 which is brought into pressure contact with the transfer roller almost at the same time, is separated by the peripheral surface of the photosensitive drum 1 and is conveyed to the fixing device 9, and is heated by the heat roller 91 and the pressure roller. After the toner is fused by heating and pressurizing 92, the toner is discharged to the outside of the apparatus via the paper discharge roller 10. The transfer roller 8 and the separation brush 59 are withdrawn from the peripheral surface of the photosensitive drum 1 after the transfer material P has passed and are ready for the next toner image formation.

On the other hand, the photosensitive drum 1 after the transfer material P is separated is the cleaning blade 2 of the cleaning device 12.
The residual toner is removed / cleaned by the pressure contact of No. 1, the charge is removed again by the exposure unit 51 and charged by the magnetic brush charging device 120, and the next image forming process starts.

C is a photoconductor, a charging device, a transfer device,
It is a detachable process cartridge in which a separation brush and a cleaning device are integrated.

[Exposure] When the image forming apparatus is used as a copying machine or a printer, the image exposure is performed by irradiating the photoconductor with reflected light or transmitted light from the original, or by reading the original with a sensor and converting it into a signal. In accordance with this signal, the laser beam is scanned, the LED array is driven, or the liquid crystal shutter array is driven to irradiate the photoconductor with light.

When used as a printer for a facsimile, the image exposure device 53 performs exposure for printing received data.

The image forming apparatus of the present invention can be generally applied to electrophotographic apparatuses such as copiers, laser printers, LED printers and liquid crystal shutter printers. It can be widely applied to devices such as light printing, plate making, and facsimile.

[Fixing] As a suitable fixing method used in the present invention, there is a so-called contact heating method. In particular, examples of the contact heating method include a heat pressure fixing method, a heat roller fixing method, and a pressure contact heat fixing method in which fixing is performed by a rotating pressure member including a fixedly arranged heating body.

[0208]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these.

[Production of Developer] (Toner Production Example 1: Example of Emulsion Polymerization Association Method) 0.90 kg of sodium n-dodecyl sulfate and 10.0 liter of pure water were put and dissolved by stirring. To this solution, 1.20 kg of Regal 330R (Carbon Black manufactured by Cabot Corporation) was gradually added, and after well stirring for 1 hour, the mixture was continuously dispersed for 20 hours using a sand grinder (medium type disperser). This is designated as "colorant dispersion liquid 1". A solution composed of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 liters of ion-exchanged water is referred to as "anionic surfactant solution A".

A solution consisting of 0.014 kg of a nonylphenol polyethylene oxide 10 mol adduct and 4.0 liters of ion-exchanged water was designated as "nonionic surfactant solution B".
And 238 g of potassium persulfate was added to ion-exchanged water 12.
The solution dissolved in 0 liter is designated as "initiator solution C".

In a GL (glass lining) reactor having a volume of 100 liter equipped with a temperature sensor, a cooling tube, and a nitrogen introducing device, a WAX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle diameter = 12)
(0 nm / solid content concentration = 29.9 mass%) 3.41 kg, “anionic surfactant solution A” total amount and “nonionic surfactant solution B” total amount were added, and stirring was started. Then
44.0 liters of ion-exchanged water was added.

When heating was started and the liquid temperature reached 75 ° C., the entire amount of “initiator solution C” was added dropwise. Then, while controlling the liquid temperature to 75 ° C ± 1 ° C, styrene 1
2.1 kg, n-butyl acrylate 2.70 kg, methacrylic acid 1.14 kg, and t-dodecyl mercaptan 55.
A solution consisting of 0 g was added dropwise. After the dropping was completed, the liquid temperature was raised to 80 ° C. ± 1 ° C., and the mixture was heated and stirred for 6 hours. Then, the liquid temperature was cooled to 40 ° C. or lower, stirring was stopped, and filtration was performed with a pole filter to obtain a latex.
This is designated as "latex-A".

The resin particles in Latex-A had a glass transition temperature of 58 ° C., a softening point of 119 ° C., a molecular weight distribution of mass average molecular weight = 135,000 and a mass average particle diameter of 11 ° C.
It was 5 nm.

A solution prepared by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 liters of ion-exchanged pure water is referred to as "anionic surfactant solution D".

A solution prepared by dissolving 0.014 kg of a 10-mol addition product of nonylphenol polyethylene oxide in 4.0 liters of ion-exchanged water is referred to as "nonionic surfactant solution E".

200 g of potassium persulfate (manufactured by Kanto Chemical Co., Inc.)
Is referred to as "initiator solution F".

In a 100 liter GL reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle, W
AX emulsion (polypropylene emulsion having a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration 29.9% by mass) 3.41 kg, "anionic surfactant solution D", and whole amount and "nonionic surfactant solution E"
The whole amount was added and stirring was started.

Next, 44.0 liters of ion-exchanged water was added. Heating was started, and when the liquid temperature reached 70 ° C., “initiator solution F” was added. Then, a solution prepared by previously mixing 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid and 9.0 g of t-dodecyl mercaptan was added dropwise. After the dropping was completed, the liquid temperature was controlled at 72 ° C. ± 2 ° C., and the mixture was heated and stirred for 6 hours. Furthermore, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature was cooled to 40 ° C. or lower and stirring was stopped. It is filtered with a pole filter, and this filtrate is designated as "latex-B".

The resin particles in Latex-B had a glass transition temperature of 59 ° C., a softening point of 133 ° C., a molecular weight distribution of mass average molecular weight = 245,000, and a mass average particle diameter of 11 ° C.
It was 0 nm.

Sodium chloride as a salting-out agent 5.36k
A solution prepared by dissolving g in 20.0 liters of ion-exchanged water is referred to as “sodium chloride solution G”.

A solution prepared by dissolving 1.00 g of a fluorine-based nonionic surfactant in 1.00 liter of ion-exchanged water is referred to as "nonionic surfactant solution H".

In a 100-liter SUS reactor equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a particle size and shape monitoring device (reactor having the configuration shown in FIG. 10, crossing angle α is 25 °), Latex-A = 2
0.0 kg, latex-B = 5.2 kg, colorant dispersion 1 = 0.4 kg, and ion-exchanged water 20.0 kg were added and stirred. Then, the mixture was heated to 40 ° C., sodium chloride solution G, isopropanol (Kanto Chemical Co., Ltd.) 6.00 k
g and nonionic surfactant solution H were added in this order. Then, after leaving it for 10 minutes, the temperature rise is started and the liquid temperature becomes 8
The temperature was raised to 5 ° C. in 60 minutes, and heated and stirred at 85 ± 2 ° C. for 0.5 to 3 hours to grow the particle size while salting out / fusing.
Next, 2.1 liters of pure water was added to stop grain size growth.

A 5 liter reaction vessel equipped with a temperature sensor, cooling tube, particle size and shape monitoring device (see FIG. 10).
5.0 kg of the fused particle dispersion liquid prepared above was placed in a reactor having a structure shown in FIG.
The shape was controlled by heating and stirring at 5 ° C ± 2 ° C for 0.5 to 15 hours. Then, it cooled to 40 degrees C or less, and stopped stirring.
Next, using a centrifuge, classification is performed in the liquid by a centrifugal sedimentation method, and the mixture is filtered through a sieve having an opening of 45 μm to obtain the filtrate as an association liquid. Then, using a Nutsche filter, wet cake-like non-spherical particles were collected from the association liquid by filtration. afterwards,
It was washed with ion-exchanged water. The non-spherical particles were dried at a suction temperature of 60 ° C. using a flash jet dryer, and then at a temperature of 60 ° C. using a fluidized bed dryer. 1 part by mass of silica fine particles was externally added and mixed with 100 parts by mass of the obtained colored particles by a Henschel mixer to obtain a black toner by an emulsion polymerization association method.

In the monitoring of the salting-out / fusion step and the shape control step, the stirring speed and the heating time were controlled to control the shape and the coefficient of variation of the shape coefficient, and further, the particle size was determined by the in-liquid classification. And a black toner (Bk toner) 1 composed of toner particles having specific shape characteristics and particle size distribution characteristics by arbitrarily adjusting the variation coefficient of the particle size distribution.
And 2 were obtained.

(Toner Production Example 2: Example of Suspension Polymerization Method) Styrene = 165 g, n-butyl acrylate = 35 g, carbon black = 10 g, di-t-butyl salicylate metal compound = 2 g, styrene-methacrylic acid copolymer = 8
6 g of paraffin wax (mp = 70 ° C.) = 20 g
Heated to 0 ℃, TK homomixer (made by Tokushu Kika Kogyo Co., Ltd.)
Was uniformly dissolved and dispersed at 12000 rpm. To this, 2,2'-azobis (2,4-valeronitrile) = 10 g as a polymerization initiator was added and dissolved to prepare a polymerizable monomer composition. Then, to 710 g of deionized water, 0.
450 g of 1 mol / l sodium phosphate aqueous solution was added, and 68 g of 1.0 mol / l calcium chloride was gradually added while stirring at 13000 rpm with a TK homomixer to prepare a suspension in which tricalcium phosphate was dispersed. . Add the above polymerizable monomer composition to this suspension,
The polymerizable monomer composition was granulated by stirring for 20 minutes at 10,000 rpm with a TK homomixer. After that, a reaction device (intersection angle α is 45 °) equipped with the turbulent flow forming member 60 as shown in FIG. 11 was used, and the reaction was performed at 75 to 95 ° C. for 5 to 15 hours. Tricalcium phosphate was dissolved and removed with hydrochloric acid, and then classified in the liquid by a centrifugal sedimentation method using a centrifuge, followed by filtration, washing and drying. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed with a Henschel mixer to obtain a toner by a suspension polymerization method.

By monitoring at the time of the polymerization and controlling the liquid temperature, the stirring rotation number, and the heating time,
Control the variation coefficient of the shape and shape factor, and further adjust the variation coefficient of the particle size and particle size distribution by classification in liquid,
Black toners (Bk toner) 3 and 4 composed of toner particles having specific shape characteristics and particle size distribution characteristics were obtained.

(Toner Production Example 3: Example of Grinding Method) A toner raw material consisting of 100 kg of styrene-n-butyl acrylate copolymer resin, 10 kg of carbon black and 4 parts by weight of polypropylene was premixed with a Henschel mixer, and a twin-screw extruder was used. Melt kneading with a hammer mill, roughly crushing with a hammer mill, crushing with a jet crusher, and dispersing the obtained powder in a hot air stream of a spray dryer (200 to 30).
Particles whose shape was adjusted at 0 ° C. for 0.05 seconds were obtained. The particles were repeatedly classified by an air classifier until the desired particle size distribution was obtained. To 100 parts by mass of the obtained colored particles, 1 part by mass of silica fine particles was externally added and mixed by a Henschel mixer to obtain a toner by a pulverization method.

In this way, the black toner (Bk) composed of toner particles having specific shape characteristics and particle size distribution characteristics, in which the coefficient of variation of the shape and the shape coefficient are controlled and the coefficient of variation of the particle size and particle size distribution is adjusted, Toner) 5 and 6 are obtained.

The shape characteristics and the like of the above toner are shown in Table 1 below.

[0230]

[Table 1]

A ferrite carrier having a volume average particle diameter of 60 μm coated with a silicone resin was mixed with each of the above toners to prepare a developer having a toner concentration of 6%, and a developer for evaluation was manufactured.

[Preparation of Photoreceptor] Intermediate layer dispersions of Examples and Comparative Examples were prepared as follows. In addition, "part" in a sentence represents a "mass part."

(Preparation of Intermediate Layer Dispersion Liquid 1) Polyamide resin CM8000 (manufactured by Toray) 1 part Titanium oxide SMT500SAS (manufactured by Teika; surface treatment is silica treatment, alumina treatment, and methylhydrogenpolysiloxane treatment) 3 parts Dispersion was carried out batchwise with a sand mill as a 10 parts methanol disperser for a dispersion time of 10 hours to prepare an intermediate layer dispersion liquid 1.

Next, the following photoconductors were prepared as the photoconductors used in the present invention. Photoreceptor 1 <Intermediate Layer> The following intermediate layer coating solution 1 was prepared and applied onto a washed cylindrical aluminum substrate by a dip coating method to form an intermediate layer having a dry film thickness of 2 μm.

<Intermediate Layer (UCL) Coating Liquid 1> The intermediate layer dispersion liquid 1 was diluted 2 times with the same mixed solvent, and allowed to stand overnight and then filtered (filter; Rigimesh filter manufactured by Nippon Pall Co., Ltd. nominal filtration accuracy: 5 μm). , Pressure; 5 N / cm ² ).

<Charge Generation Layer> The following compositions were mixed and dispersed using a sand mill to prepare a charge generation layer (CGL) coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm on the intermediate layer.

Y-type oxytitanyl phthalocyanine (Cu-Kα characteristic X-rays have a maximum peak angle of 2θ of 27.3 at 27.3) 20 g Polyvinyl butyral (# 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.) 10 g t-butyl acetate 700 g 4-methoxy-4-methyl-2-pentanone 300 g <Charge transport layer> The following compositions were mixed and dissolved to prepare a charge transport layer (CTL) coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a thickness of 24 μm.

Charge Transport Material [N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine] (Compound A) 75 g Polycarbonate Resin “Upilon-Z300” (Mitsubishi Gas Chemical Co., Ltd. 100 g methylene chloride 750 g <Protective layer> Polysiloxane resin (containing 1% by mass of silanol group) consisting of 80 mol% of methyl siloxane unit and 20 mol% of methyl-phenyl siloxane unit on the charge transport layer. Molecular sieve 4A (Wako Pure Chemical Industries, Ltd.) was added to parts by mass, and the mixture was left standing for 15 hours for dehydration treatment. This resin was dissolved in 10 parts by mass of toluene, and 5 parts by mass of methyltrimethoxysilane and 0.2 parts of dibutyltin acetate were added thereto.
Parts by mass were added to make a uniform solution. To this, 6 parts by mass of dihydroxymethyltriphenylamine was added and mixed, and this solution was applied as a protective layer having a dry film thickness of 1 μm to give 120
The photoreceptor 1 was prepared by drying at 1 ° C. for 1 hour.

Photoreceptor 2 <Undercoat layer> Titanium chelate compound (TC-750: manufactured by Matsumoto Pharmaceutical Co., Ltd.) 30 g Silane coupling agent (KBM-503: manufactured by Shin-Etsu Chemical Co., Ltd.) 17 g 2-propanol 150 ml φ100 mm using the above coating liquid It was coated on the cylindrical conductive support of to give a dry film thickness of 0.5 μm.

<Charge Generation Layer> Y-type titanyl phthalocyanine (Cu-Kα characteristic X-ray has a maximum peak angle of 2θ of 27.3 at 2θ of 27.3) 60 g Silicone-modified butyral resin (X-40-1211M: manufactured by Shin-Etsu Chemical Co., Ltd.) ) 700 g 2-butanone 2000 ml was mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating liquid. This coating solution was applied onto the undercoat layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.2 μm.

<Charge Transport Layer> Charge transport material [N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine] 225 g Polycarbonate (viscosity average molecular weight 30,000) 300 g Antioxidant 16 g Dichloromethane 2000 ml was mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a dry film thickness of 20 μm.

<Protective Layer> On the charge transport layer, 10 parts by mass of a molecular weight polysiloxane resin (containing 1% by mass of silanol groups) consisting of 80 mol% of methylsiloxane units and 20 mol% of methyl-phenylsiloxane units was prepared. Sieve 4A was added and the mixture was left standing for 15 hours for dehydration. This resin was dissolved in 10 parts by mass of toluene, and 5 parts by mass of methyltrimethoxysilane and 0.2 parts of dibutyltin acetate were added thereto.
Parts by mass were added to make a uniform solution.

6 parts by mass of dihydroxymethyltriphenylamine was added thereto and mixed, and this solution was dried to a film thickness of 1 μm.
m as a protective layer and dried at 120 ° C. for 1 hour to prepare a photoconductor 2.

Photoreceptor 3 A charge transport layer was prepared in the same manner as the photoconductor 2.

Dihydroxymethyltriphenylamine in the protective layer was converted into 4- [2- (triethoxysilyl) ethyl]
A photoconductor 3 was prepared in exactly the same manner except that triphenylamine was used instead.

Photoreceptor 4 A charge transport layer was prepared in the same manner as the photoconductor 2.

<Protective Layer> Methyltrimethoxysilane 150 g Dimethyldimethoxysilane 30 g Reactive charge transporting compound 1 50 g Antioxidant 2 1 g 1-Butanol 225 g Colloidal silica (30% by mass methanol solution) 100 g 2% by mass acetic acid 106 g Aluminum tris Acetylacetonate 1 g Silane compound and 1-butanol, 2% by mass acetic acid were mixed and stirred at a temperature of 40 ° C. for 16 hours while stirring.
A reactive charge transporting compound 1, an antioxidant 2, and aluminum trisacetylacetonate were added and further stirred at room temperature for 1 hour to prepare a coating liquid for a protective layer. A resin layer having a dry film thickness of 1 μm is formed on the charge transport layer by using a circular amount regulation type coating device, and the resin layer is formed at 110 ° C.
By carrying out heat curing for 1 hour, a protective layer of a siloxane-based resin layer having a structural unit having a charge transporting property and having a crosslinked structure was formed to prepare a photoconductor 4.

Photoreceptor 5 A photoreceptor 5 was prepared in the same manner as in the preparation of the photoreceptor 2 except that the protective layer was removed and the charge transport layer had a dry film thickness of 21 μm.

Photoreceptor 6 A charge transport layer was prepared in the same manner as the photoconductor 2.

<Protective Layer> Acrylic siloxane-containing resin (HPC7506 (solid content 39%): manufactured by JSR) 150 g Reactive charge transporting compound 1 6 g Antioxidant 2 0.3 g 2-propanol 115 g HPC406H (manufactured by JSR) ) 4g was mixed and the coating liquid for protective layers was prepared. A 2 μm-thick protective layer of this coating liquid was formed on the charge transport layer using a circular amount regulation type coating device, and heat-cured at 120 ° C. for 1 hour to prepare a photoconductor 6.

Photoreceptor 7 A charge transporting layer was prepared in the same manner as in Photoreceptor 2. <Protective layer> Silyl group-containing vinyl resin (A) (solid content 50% by mass) 60 g Methyltrimethoxysilane 70 g Reactive charge transporting compound 1 40 g Antioxidant 2 2 g 2-Propanol 150 g 2-Butanone 100 g 3% by mass 10 g of acetic acid 10 g and aluminum chelate A (W) (manufactured by Kawaken Chemical Co., Ltd.) were mixed to prepare a coating solution for a resin layer. A resin layer having a thickness of 2 μm is formed on the charge transporting layer by using a circular amount regulating type coating device, and the coating liquid is heat-cured at 120 ° C. for 1 hour to form a siloxane resin layer. Was produced.

Photoreceptor 8 A charge transport layer was prepared in the same manner as the photoconductor 2.

<Protective Layer> Phenoxy resin (PAPHEN
PHENOXY RESIN PKHJ; Pheno
xy Associates product number average molecular weight 160
(00) 50 parts was dissolved in 500 parts of 1,4-dioxane, and 100 parts of tetramethoxysilane partially hydrolyzed condensate (M silicate 51 manufactured by Tama Chemical Industry Co., Ltd.) and 2.5 parts of dibutyltin dilaurate as a catalyst were added. Then, the mixture was stirred at room temperature for 2 hours to obtain an alkoxysilane-modified phenoxy resin solution. 40% of the reactive charge transporting compound 1 is added here.
Part, 2 parts of antioxidant 2 and 4 parts of aluminum chelate A (W) (Kawaken Chemical Co., Ltd .: aluminum trisacetylacetonate) were added to prepare a coating solution for a surface protective layer.
This coating solution was applied onto the charge transport layer by a circular amount control type coating device, heated and cured at 110 ° C. for 90 minutes, and was a block copolymer of a phenoxy resin and a siloxane condensate having a film thickness of 3.0 μm. In addition, a surface protective layer having a crosslinked resin structure was formed to prepare a photoconductor 8.

Photoreceptor 9 A photoreceptor 9 was prepared in the same manner as the photoreceptor 1 except that the thickness of the photoreceptor layer was 25 μm and no protective layer was applied.

[0255]

[Chemical 1]

<Evaluation><Evaluation condition for using charging roller> A commercially available laser printer was remodeled into a roller charging device to carry out actual image evaluation. The conditions are shown below.

(Charging Roller) A charging roller composed of the following conductive elastic member and the like was used on an 8 mmφ stainless steel cored bar.

Charging roller No. 1 As a material for the conductive elastic layer, polynorbornene rubber /
A carbon black / naphthene-based oil and, if necessary, a vulcanizing agent, a vulcanization accelerator, an additive, etc. were mixed and adjusted, and then filled in a mold to form a conductive elastic layer. On this layer, polyester urethane as a coating layer forming material, particle size of about 0.5
Immersing in a composition liquid consisting of a resin powder (μm), carbon black, and a solvent (MEK / dimethylformamide), coating, drying and heat treatment to form a coating layer made of a urethane layer. 1 (Rz; 5.5μ
m) was obtained.

The charging conditions are shown below. Photoconductor contact pressure: 500 mN / cm DC voltage applied to charging member: -600 V, AC voltage: 2,000 Vp-p Frequency: 150 Hz Development conditions are shown below.

DC bias: -500 V Dsd (distance between photoconductor and developing sleeve): 600 μm Developer layer regulation: Magnetic H-Cut system developer layer thickness: 700 μm Developing sleeve diameter: 40 mmφ Further, as a fixing method, heat roll fixing is used. And a method of cleaning the untransferred toner remaining on the photoconductor by a blade cleaning method.

Image exposure means: semiconductor laser developing means: two-component contact reversal development cleaning condition in which a photoreceptor and a developer contact each other: cleaning conditions: hardness 70 °, repulsion elasticity 34%, thickness 2 mm, free length 7 mm. The cleaning blade was brought into contact with the counter by a weight load method so that the linear pressure was 200 mN / cm.

<Conditions for Evaluation of Use of Magnetic Brush> A commercially available laser printer was modified into a magnetic brush charging device to carry out actual copying evaluation. The conditions are shown below.

(Magnetic Brush Charging Device) It has the structure of FIG.

Preparation of Magnetic Particles 1 Magnetic particles 1 forming a magnetic brush for charging were prepared as follows.

Preparation of Magnetic Particles 1 Fe ₂ O ₃ : 50 mol% CuO: 24 mol% ZnO: 24 mol% The above is pulverized and mixed, and a dispersant, a binder resin and water are added to make a slurry, which is then produced by a spray dryer. Grain operation was performed, and after classification, firing was performed at 1125 ° C. The obtained magnetic particles were crushed and then classified to obtain magnetic particles 1 having a volume average particle diameter of 27 μm. The resistance value of the magnetic particles 1 was 2 × 10 ⁷ Ω · cm.

<< Mass Adder >> A mass adder as described below was prepared and brought into close contact, adhesion or contact with the inside of the photosensitive drum.

Mass adder 1 Resin foam Calmflex F9M (manufactured by INOAC CORPORATION) Plate (length 300 × width 70 × thickness 10)
mm, 12.2 g) is closely attached to the inside of the photoconductor drum. (Corresponding to 11% of the mass of the photoreceptor including the flange) Mass adder 2 A resin foam Calmflex F6 (manufactured by INOAC Corporation) plate (size same as above, 11.7 g) was brought into close contact with the inside of the photoreceptor drum. thing. (Corresponding to 10% of the mass of the photosensitive member including the flange) Mass adder 3 The mass adder 2 was prepared in the same manner as the mass adder 2 except that the resin foam was 46.8 g.

Mass adder 4 A plate made of polystyrene foam (same as above) is brought into contact with the inner surface of the photosensitive drum by utilizing self-elasticity. (Equivalent to 5% of the mass of the photosensitive member including the flange) Mass addition member 5 An iron cylinder having a mass of 60 g bonded to the inside of the central portion of the photosensitive drum. (Equivalent to 54% of the mass of the photoconductor including the flange) Mass adder 6 A semicylindrical body made of aluminum and having a mass of 15 g is adhered to the inside displaced by 3 cm from the center of the photoconductor drum. (Equivalent to 13% of the mass of the photoconductor including the flange) Mass adder 7 A plate made of polyphenylene sulfide and having a thickness of 3 mm was brought into contact with the inner surface of the photoconductor drum by utilizing self-elasticity.
(Equivalent to 5% of the mass of the photosensitive member including the flange) [Evaluation] The above photosensitive member, mass addition member, toner and charging method are combined as shown in Table 2, and A4 paper is printed at 30 ° C. and 80% RH environment. Using 10,000 copies with a printing rate of 10%, cleaning properties such as blade flipping, fogging of copy images, sharpness, image unevenness, abnormal noise and uneven wear were measured, and the following evaluation criteria were used. An evaluation was made.

To evaluate the copy image, an original image in which a character image with a pixel ratio of 7%, a human face photograph, a solid white image, and a solid black image are equally divided into quarters is copied in A4 to obtain a solid white image. Images, solid black images, and fine line images were evaluated.

The results obtained are shown in Table 2. (Blade flipping) The cleaning blade flipping was evaluated by actually looking at the blade after 10,000 sheets were actually photographed.

∘: No abnormality at all ∘: Practically acceptable range ×: Problem caused by turning (fog) For fog, the density of each image is RD-918 manufactured by Macbeth Co. Use to measure the absolute reflection density,
It was judged by the solid white image density. If the increase in residual potential increases, the image density decreases, and if the decrease in charging potential increases, fogging occurs.

∘: 0.005 or less (good) O: greater than 0.005 and less than 0.01 (no practical problem) x: 0.01 or more (problem in practical use) ( Sharpness) The sharpness was determined by visually observing the number of fine lines per 1 mm that can be discriminated in the copy image of the fifth generation.

◎ ・ ・ ・ 7 lines / mm or more (good) ○ ・ ・ ・ 4 lines / mm to 6 lines / mm (no practical problem) × ・ ・ ・ 4 lines / mm or less (practical problems) ) (Image unevenness) Image unevenness is the density difference (Δ
HD = maximum density-minimum density). If the uniformity of the charging potential decreases and the uneven wear increases, the image unevenness increases.

∘: 0.05 or less (good) O: Greater than 0.05 and less than 0.1 (no problem in practical use) x: 0.1 or more (problem in practical use) ( Abnormal noise) For the abnormal noise measurement, sensory evaluation was performed by installing an evaluation machine in an anechoic room with a background noise of 30 dB (A).

⊚: No particular occurrence, good ○: Squeaking sound, but no problem in practical use ×: Not in a negligible state and has practical problems (uneven wear) Uneven wear is a photoreceptor The difference between the center value and the average value of 10 points in the circumferential direction at the end portion of 3 cm was measured. The judgment criteria are as shown below.

[0276] ◎ ・ ・ ・ Difference 5μm or less (good) ○: 5 to 7 μm difference (no problem level) ×: Difference of 7 μm or more (there is a problem in practical use)

[0277]

[Table 2]

[0278]

According to the present invention, there is provided an image forming apparatus, an image forming method, a process cartridge, and a photoconductor which are free from jitter due to vibrations in the photoconductor drum and the image forming apparatus, and are free from variations in ruled line width and density. Can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an electrophotographic printer as an example of an image forming apparatus.

FIG. 2 is a cross-sectional view of a process cartridge that can be attached to and detached from an image forming apparatus.

FIG. 3 is a configuration diagram showing an example of a photosensitive drum and a charging roller.

FIG. 4 is a cross-sectional view of a photosensitive drum in which a mass addition body is inserted.

FIG. 5 is a diagram illustrating toner particles having no corners.

FIG. 6 illustrates an example of an image forming apparatus that performs roller charging.

FIG. 7 is a configuration diagram of a magnetic brush charging device.

FIG. 8 is a diagram showing a relationship between an AC bias voltage of the charging device and a charging potential.

FIG. 9 is an image forming apparatus 1 having a magnetic brush charging device.
Sectional drawing which shows an example.

FIG. 10 is a perspective view showing an example of a reaction device used for forming a laminar flow.

FIG. 11 is a perspective view showing an example of a reaction device including a turbulent flow forming member.

[Explanation of symbols]

1 photoconductor drum 2 charging roller 3 laser scanner 4 Developing device 5 cassettes 6 paper feed rollers 7 Conveyor rollers 8 Transfer roller 9 Fixing device 10 Paper ejection roller 11 Output tray 12 Cleaning device 13, 20 High voltage power supply 17 Development sleeve 18 Static elimination lamp 19 Conveyor belt 21 cleaning blade 51 exposure section 60 Turbulence forming member

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/02 101 G03G 15/02 102 102 21/00 318 21/10 9/08 384 325 F term (reference) ) 2H005 AA01 AB06 CA04 EA05 EA10 2H035 CA07 CB03 CG03 2H068 AA02 AA03 AA04 AA52 AA54 AA60 BA12 BA58 BB32 BB49 BB57 CA32. HB45 HB46 HB47 HB48 JA02 MA03 MA12 MA14 MA20 MB02 MC06 NA06

Claims (20)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a cylindrical conductive support, charging means for charging the surface of the photosensitive member, and exposing the surface of the photosensitive member charged by the charging means. Exposing means for forming an electrostatic latent image by the above, a developing means for developing the electrostatic latent image formed by the exposing means to form a toner image, and a toner image formed by the developing means In an electrophotographic image forming apparatus having a transfer means for transferring to a sheet and a cleaning means for removing foreign matters such as toner remaining on the surface of the photoconductor after the transfer by the transfer means, a mass is added to the inside of the photoconductor. An electrophotographic image forming apparatus, wherein a body is provided and the photoreceptor is an organic photoreceptor containing a siloxane resin as a surface layer. 2. The electrophotographic image forming apparatus according to claim 1, wherein at least a part of the mass addition body or a part of a member including the mass addition body is in contact with the inner surface of the photoconductor. . 3. The electrophotographic image forming apparatus according to claim 1, wherein the mass addition body is a vibration suppressing material. 4. The electrophotographic image forming apparatus according to claim 1, wherein the mass addition body is a sound absorbing material. 5. The electrophotographic image forming apparatus according to claim 1, wherein the siloxane-based resin has a structural unit having a charge transporting ability and has a crosslinked structure. 6. The electrophotographic image forming apparatus according to claim 1, wherein the siloxane resin has a thermoplastic organic polymer component. 7. The electrophotographic toner according to claim 1, wherein a toner having a variation coefficient of the shape factor of the toner of 16% or less and a variation coefficient of the number particle size distribution of 27% or less is used as the toner. Image forming apparatus. 8. The toner has a shape factor of 1.0 to 1.6.
The electrophotographic image forming apparatus according to any one of claims 1 to 7, further comprising: 65% by number or more of toner particles within the range. 9. The toner has a shape factor of 1.2 to 1.6.
The electrophotographic image forming apparatus according to any one of claims 1 to 7, further comprising: 65% by number or more of toner particles within the range. 10. The toner according to claim 1, wherein the toner contains not less than 50% by number of toner particles having no corners.
The electrophotographic image forming apparatus according to claim 1. 11. The number average particle diameter of the toner is 3 to 8 μm.
The electrophotographic image forming apparatus according to claim 1, wherein the electrophotographic image forming apparatus is m. 12. When the particle diameter of the toner particles is D (μm), the natural logarithm lnD is plotted on the horizontal axis, and the horizontal axis shows a number-based particle size distribution divided into a plurality of classes at 0.23 intervals. The sum (M) of the relative frequency (m1) of the toner particles included in the most frequent class in the histogram and the relative frequency (m2) of the toner particles included in the second most frequent class after the most frequent class is 70% or more. 2. The method according to claim 1, wherein
The electrophotographic image forming apparatus according to any one of 1 to 11. 13. The electrophotographic image forming apparatus according to claim 1, wherein the toner is obtained by polymerizing at least a polymerizable monomer in an aqueous medium. 14. The electrophotographic image forming apparatus according to claim 1, wherein the toner is obtained by salting out / fusing at least resin particles in an aqueous medium. 15. The toner according to claim 1, wherein the toner is a styrene- (meth) acrylate resin.
The electrophotographic image forming apparatus according to claim 1. 16. The electrophotographic image forming apparatus according to claim 1, wherein the cleaning unit is a polyurethane cleaning blade. 17. The electrophotographic image forming apparatus according to claim 1, wherein the charging unit is contact charging. 18. An electrophotographic image forming method using the electrophotographic image forming apparatus according to claim 1. Description: 19. The electrophotographic image forming apparatus according to claim 1, wherein at least one of a charging unit, an exposing unit, a developing unit, a transferring unit and a cleaning unit, and an electrophotographic photosensitive member are provided. A process cartridge, which is formed so as to be combined with the main body of the image forming apparatus so that the process cartridge can be integrally inserted and removed. 20. An electrophotographic photosensitive member having a photosensitive layer on a cylindrical conductive support, wherein a mass addition member is provided inside said photosensitive member, and said photosensitive member has a siloxane resin layer as a surface layer. An electrophotographic photoreceptor, which is an organic photoreceptor.