JP2011175140A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of obtaining a stable image of high image quality irrespective of a long-term use, without elongating a standby time, and to especially provide the image forming apparatus which is improved in image defects such as image flowing, caused by activated gas such as NOx or ozone, easily occurring in the vicinity of a charger in a high temperature and high humidity environment. <P>SOLUTION: The image forming apparatus includes at least: an organic photoreceptor; a charging means to charge the photoreceptor; an exposure means to expose the charged photoreceptor surface to form an electrostatic latent image; and a developing means to develop the electrostatic latent image by a two-component developer containing toner and carrier to form a visible image. The photoreceptor includes a surface layer containing a reaction product of curable compound including at least a reactive group. The image forming apparatus further includes: a carrier supply means to supply the carrier to the surface of the photoreceptor; and a carrier removing means to remove the carrier supplied to the surface of the photoreceptor. The carrier supply means and the carrier removing means are activated in a period other than an image formation period. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus used for electrophotographic image formation.

  Recently, as the size of the electrophotographic image forming apparatus has been reduced, the diameter of the photoconductor has been reduced, and there has been a strong demand for higher durability of the photoconductor due to the increase in speed and maintenance of the apparatus. It was.

  From this point of view, the organic photoreceptor is generally soft because the surface layer is mainly composed of a low molecular charge transport material and an inert polymer, and when used repeatedly for image formation, it depends on the development process and cleaning process. There is a drawback that wear is likely to occur due to a physical load. In addition, due to the demand for higher image quality, along with the reduction in the toner particle size, the rubber hardness of the cleaning blade and the contact pressure must be increased for the purpose of improving the cleaning property, and the factors that promote the wear of the photoconductor It has become. Such wear of the photoreceptor deteriorates electrical characteristics such as sensitivity deterioration and chargeability, and causes abnormal images such as image density reduction and background stains. Further, scratches where wear is locally generated cause streak-like stain images due to poor cleaning. At present, the life of the photosensitive member has been replaced due to such wear and scratches.

  In order to increase the durability of organic photoreceptors, it is indispensable to reduce the amount of wear described above, and in order to impart excellent cleaning properties and transferability, organic photoreceptors having good surface properties are required. These are the most pressing issues in the technical field.

  Techniques for improving the abrasion resistance of the photosensitive layer include (1) using a curable binder for the surface layer (Patent Document 1), and (2) using a polymeric charge transport material (Patent Document 2). (3) An inorganic filler dispersed in the surface layer (Patent Document 3). Although all of these technologies can provide a certain level of wear resistance, the presence of unreacted groups, the polarity of the charge transport material itself, the presence of polar groups on the surface of the particles, etc. can affect the effects of active gases such as NOx and ozone. It was easy to receive, particularly in a high temperature and high humidity environment, causing a phenomenon called image flow, and image characteristics were insufficient.

  On the other hand, a technique is disclosed in which inorganic fine particles such as strontium titanate are contained on the surface of toner particles, and the image characteristics under a high temperature and high humidity environment are improved by the polishing action of the inorganic fine particles (Patent Document 4, Patent Document). 5). However, even if these techniques are used, the improvement in wear resistance and the prevention of image flow defects are compatible, and the market demand has not been satisfied.

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 JP 2000-284509 A JP 2007-33485 A

  The object of the present invention is to prevent image defects such as image flow that are likely to occur particularly in high-temperature and high-humidity environments when using an organic photoreceptor with high wear resistance, and achieve both durability and image quality at a high level. It is to let you.

  In order to improve the abrasion resistance of the photoreceptor, it is effective to form a surface layer using a curable binder. However, if the abrasion resistance is increased, toner particles, inorganic fine particles added to the toner, etc. The rubbing of the surface of the photoreceptor with the components is insufficient because the rubbing force is low. A refresh function due to moderate wear on the surface of the photoreceptor cannot be expected, and image defects (image flow) occur during repeated use, particularly in a high humidity environment.

  As a countermeasure, especially when the image forming apparatus is started after a long stop, in order to remove discharge products accumulated on the surface of the photoconductor, the photoconductor is idly rotated and a cleaning blade or a magnetic brush of a two-component developer is used. For example, a mode for rubbing the surface of the photoreceptor is provided. However, in a photoconductor employing a surface layer with high wear resistance, even if this method is used, the time until a normal image is obtained becomes long and impractical.

  An object of the present invention is to provide an image forming apparatus that can obtain a stable high-quality image even in long-term use without extending the standby time, and is generated in the vicinity of the charging device particularly in a high-temperature and high-humidity environment. It is an object of the present invention to provide an image forming apparatus in which image defects such as image flow caused by an active gas such as NOx and ozone are improved.

  The inventors of the present application use a photoconductor having high wear resistance, and a carrier having a specific gravity higher than that of a toner and a particle size larger than that of a toner causes excessive wear and scratches on the surface layer. Thus, the inventors have found that the ability to remove discharge products has been dramatically improved, and that a normal image can be obtained in a short time, leading to the present invention.

  That is, the said subject of this invention is achieved by the structure described below.

1.
An organic photoreceptor, a charging means for charging the photoreceptor, an exposure means for exposing the charged photoreceptor surface to form an electrostatic latent image, and a two-component containing the electrostatic latent image with toner and a carrier In the image forming apparatus having at least a developing unit that develops a visible image by developing with a developer, the photoreceptor includes a surface layer containing a reaction product of a curable compound having at least a reactive group. And a carrier supply unit that supplies a carrier to the surface of the photoconductor and a carrier removal unit that removes the carrier supplied to the surface of the photoconductor, and is operated outside the time of image formation. An image forming apparatus.

2.
The image forming apparatus according to claim 1, wherein the carrier supply unit is a developing unit.

3.
3. The image forming apparatus according to claim 1, wherein the carrier removing unit is a cleaning unit.

4).
4. The image forming apparatus according to claim 3, wherein the cleaning unit has a configuration in which a brush and a blade are used in combination.

5.
The image forming apparatus according to any one of claims 1 to 4, wherein the surface layer of the organic photoreceptor contains inorganic fine particles.

6).
6. The image forming apparatus according to claim 5, wherein the inorganic fine particles are surface-treated with a compound having a polymerizable functional group.

7).
7. The image forming apparatus according to claim 1, wherein the organic photoconductor has a universal hardness value (HU) of 150 N / mm ² or more and 500 N / mm ² or less.

  By applying the image forming apparatus of the present invention, it is possible to provide an image forming apparatus capable of obtaining a stable high-quality image output even in long-term use without extending the standby time. It is possible to provide an image forming apparatus in which an image defect such as an image flow caused by an active gas such as NOx or ozone, which tends to occur near the charging device, is improved.

1 is a configuration diagram of an image forming apparatus according to the present invention. 1 is a cross-sectional view of a developing device according to the present invention.

  Embodiments of the present invention will be described below.

(Image forming device)
FIG. 1 is a configuration diagram of a color image forming apparatus A according to the present invention.

  The color image forming apparatus A is referred to as a tandem type color image forming apparatus. A plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a belt-like intermediate transfer member 6, a sheet feeding device 20, and a fixing device 30 are used. It consists of and.

  An image reading device SC is installed on the color image forming apparatus A. The document placed on the document table is scanned and exposed by the optical system of the document image scanning exposure device of the image reading device SC and read by the line image sensor. The analog signal photoelectrically converted by the line image sensor is subjected to analog processing, A / D conversion, shading correction, image compression processing and the like in the image processing unit, and then input to the optical writing means 3Y, 3M, 3C, 3K. Is done.

  An image forming unit 10Y that forms a yellow (Y) image includes a charging unit 2Y, an optical writing unit 3Y, a developing device 4Y, and a cleaning unit 5Y disposed around the image carrier 1Y. An image forming unit 10M that forms a magenta (M) color image includes an image carrier 1M, a charging unit 2M, an optical writing unit 3M, a developing device 4M, and a cleaning unit 5M. An image forming unit 10C for forming a cyan (C) color image includes an image carrier 1C, a charging unit 2C, an optical writing unit 3C, a developing device 4C, and a cleaning unit 5C. An image forming unit 10K that forms a black (K) image includes an image carrier 1K, a charging unit 2K, an optical writing unit 3K, a developing device 4K, and a cleaning unit 5K.

  The charging unit 2Y and the optical writing unit 3Y, the charging unit 2M and the optical writing unit 3M, the charging unit 2C and the optical writing unit 3C, and the charging unit 2K and the optical writing unit 3K constitute a latent image forming unit.

  4Y, 4M, 4C, and 4K are developing devices that contain a two-component developer composed of a small particle size toner of yellow (Y), magenta (M), cyan (C), and black (K) and a carrier.

  The intermediate transfer body 6 is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming means 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating intermediate transfer body 6 by the primary transfer means 7Y, 7M, 7C, and 7K, and a combined color image is obtained. It is formed.

  The recording paper P stored in the paper feeding cassette 21 of the paper feeding device 20 is fed by a paper feeding means (first paper feeding unit) 22, and is fed with paper feeding rollers 23, 24, 25, 26 and registration rollers (first rollers). (Second paper feed unit) 27 and the like, and is conveyed to the secondary transfer means 9, and the color image is transferred onto the recording paper P.

  Note that the three-stage sheet feeding cassettes 21 arranged vertically in the vertical direction below the color image forming apparatus A have substantially the same configuration. The three-stage sheet feeding means 22 has almost the same configuration. The sheet feeding cassette 21 and the sheet feeding means 22 are collectively referred to as a sheet feeding device 20.

  The recording paper P onto which the color image has been transferred is sandwiched by the fixing device 30 and the color toner image (or toner image) on the recording paper P is fixed by applying heat and pressure to the recording paper P. The sheet is fixed on the upper side, sandwiched between the sheet discharge rollers 28 and placed on a sheet discharge tray 29 outside the apparatus.

  On the other hand, after the color image is transferred to the recording paper P by the secondary transfer means 9, the residual toner is removed by the cleaning means 8 from the intermediate transfer body 6 from which the recording paper P is separated by curvature.

  Hereinafter, the image carriers 1Y, 1M, 1C, and 1K are referred to as the image carrier 1 (hereinafter referred to as the photoreceptor 1), and the developing devices 4Y, 4M, 4C, and 4K are referred to as the developing device 4.

[Development equipment]
FIG. 2 is a sectional view showing an embodiment of the developing device 4 according to the present invention.

  The housing of the developing device 4 has a two-part configuration including a lower lower casing 40 and an upper upper casing 50, and can be opened and closed.

  In the lower casing 40 of the developing device 4, a developing roller 41, a first developer stirring and conveying member (hereinafter referred to as a first stirring member) 43, and a second developer stirring and conveying member (hereinafter referred to as a second stirring member). ) 44, a developer supply roller (hereinafter referred to as a supply roller) 45, a developer guide member (hereinafter referred to as a guide member) 46, and the like.

  The lower casing 40 includes a developer supply chamber 401 that houses the first stirring member 43 and a developer stirring chamber 402 that houses the second stirring member 44. The developer supply chamber 401 and the developer agitation chamber 402 are formed on both sides of a partition wall 403 that stands upright from the bottom of the lower casing 40.

  The developing roller 41 includes a rotatable developing sleeve (developer carrier) 41A and a fixed magnetic field generating means (magnet roll) 41B.

  At the opposing proximity point of the developing sleeve 41A and the first stirring member 43, the developing sleeve 41A rotates from below to above, and the first stirring member 43 rotates from above to below.

  The developing roller 41 is disposed so as to face the photosensitive member 1 carrying the electrostatic latent image, and is driven and rotated by a driving source (not shown). On the developing sleeve 41A, an AC voltage from the AC power source E1 and a DC voltage from the DC power source E2 are superimposed as a developing bias.

  The magnetic field generating means 41B is arranged inside the developing sleeve 41A and has seven magnetic poles N1, N2, N3, N4, S1, S2, and S3. The magnetic pole N1 is a developing main magnetic pole, the magnetic pole N2 is a stripping magnetic pole, and the magnetic pole N3 is a regulating magnetic pole that regulates the developer conveyance amount on the developing roller 41. These seven magnetic poles N1, N2, N3, N4, S1, S2, and S3 form the magnetic force distribution shown in the figure.

  The tip of the developer amount regulating member 51 is disposed at a position near the regulating magnetic pole N3 of the magnetic field generating means 41B.

  Two magnetic poles N2 and N3 adjacent to each other among the plurality of magnetic poles of the magnetic field generating means 41B are arranged in the same polarity to form a repulsive magnetic field. The stripping magnetic pole N2 for stripping off the developer strips off and disperses the developer on the developing sleeve 41A. The regulating magnetic pole N3 for receiving the developer draws up the developer supplied by the supply roller 45 and deposits it on the developing sleeve 41A.

  The first agitating member 43 agitates and conveys the developer conveyed from the second agitating member 44 and supplies it uniformly to the developing roller 41. The first stirring member 43 and the second stirring member 44 are both helical screw members.

  The second agitating member 44 is arranged in parallel with the first agitating member 43, and mixes and agitates the new toner replenished from the toner replenishing means 47 and the developer recirculated from the developing sleeve 41 </ b> A to the upstream side of the first agitating member 43. To the part.

  The first stirring member 43 conveys the developer in the direction of the rotation axis and releases the developer in a direction substantially perpendicular to the rotation axis.

  The developer amount regulating member 51 is made of a magnetic material, faces the regulating magnetic pole N3, and regulates the developer layer thickness on the developing sleeve 41A. The supply roller 45 includes magnetic field generating means having five pole magnets N1, N2, N3, S1, and S2 arranged in a fixed manner, holds and conveys the developer conveyed from the first stirring member 43, and develops a sleeve 41A. To send.

  The guide member 46 is disposed in the vicinity of the opposing proximity point between the developing sleeve 41 </ b> A and the first stirring member 43. The guide member 46 separates the lower developer, which is peeled off from the developing sleeve 41A and conveyed in the direction of the white arrow shown in FIG. 2, from the upper developer supplied to the developing sleeve 41A, and the supply roller 45. The developer conveyed by is accumulated and guided to the developing roller 41. The guide member 46 is formed of a nonmagnetic material, for example, a synthetic resin such as ABS resin, nonmagnetic stainless steel, aluminum alloy, copper alloy, ceramics, or the like.

  The developer scraped up by the rotation of the first stirring member 43 is conveyed by the rotation of the supply roller 45 containing the magnetic pole, and then moves in one direction on the guide member 46 in a rectified manner so as to rotate. 41, the developer height is regulated by the developer amount regulating member 51, and the developer is conveyed to the developing area facing the photoreceptor 1.

(Career)
[Coating resin layer]
Resins suitable for forming the carrier coating layer according to the present invention include polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, and chlorosulfonated polyethylene; polyacrylates such as polystyrene and polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyvinyl Polyvinyl and polyvinylidene resins such as alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polybiliketone; copolymers such as vinyl chloride-vinyl acetate copolymer and styrene-acrylic acid copolymer; polytetrachlor Fluorine resins such as ethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyamides; polyesters; polyurethanes; polycarbonates; Amino resins such as formaldehyde resins; epoxy resins and the like.

  Among these, from the viewpoint of depleting the carrier coat resin layer to some extent through long-term use and preventing toner spent, a styrene-acrylic acid copolymer is preferable, and a silicone resin or a crosslinked resin in which the resin layer hardly wears is not suitable.

[Core material (magnetic particles)]
Examples of the core material (also referred to as core particle or magnetic particle) used in the carrier according to the present invention include iron powder, magnetite, various ferrite-based particles, or those obtained by dispersing them in a resin. Magnetite and various ferrite particles are preferred. As the ferrite, ferrite containing heavy metals such as copper, zinc, nickel and manganese and light metal ferrite containing alkali metals and / or alkaline earth metals are preferable.

The magnetic particle diameter is 10 to 100 μm, preferably 20 to 80 μm in volume average particle diameter. Furthermore, the magnetization characteristics of the carrier itself are preferably 2.5 × 10 ^{−5 to} 15.0 × 10 ⁻⁵ Wb · m / kg in saturation magnetization.

  The volume average particle diameter of the magnetic particles is a volume-based average particle diameter measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympatech) equipped with a wet disperser. The saturation magnetization is measured by “DC magnetization characteristic automatic recording device 3257-35” (manufactured by Yokogawa Electric Corporation).

  The average thickness of the resin layer is preferably 50 to 4000 nm, more preferably 200 to 3000 nm from the viewpoint of achieving both carrier durability and low resistance.

  The average thickness of the resin layer is a value calculated by the following method.

  A carrier flake is prepared with a focused ion beam sample preparation apparatus (SMI2050 manufactured by SSI Nano Technology Co., Ltd.), and then the cross section of the thin piece is 5000 with a transmission electron microscope (JEM-2010F manufactured by JEOL Ltd.). Observation was performed with a double field of view, and the average value of the portion having the maximum film thickness and the portion having the minimum film thickness in the visual field was defined as the average thickness of the resin layer.

[Production of resin layer]
Specific methods for producing the resin layer include a wet coating method and a dry coating method. Each method is described in detail below.

As a wet coating method,
(1) Fluidized bed type spray coating method A method in which a coating solution in which a coating resin is dissolved in a solvent is spray-coated on the surface of magnetic particles using a fluidized bed and then dried to produce a coating (2) Immersion type coating Method A method in which magnetic particles are immersed in a coating solution in which a coating resin is dissolved in a solvent, followed by drying, and then dried to produce a coating. (3) Polymerization method In a coating solution in which a reactive compound is dissolved in a solvent Examples of the method include a method in which magnetic particles are immersed and coated, and then a heat treatment is applied to perform a polymerization reaction to produce a film.

  In the dry coating method, resin particles are deposited on the surface of the core particles to be coated, and then mechanical impact force is applied to melt or soften the resin particles deposited on the surface of the particles to be coated. And a method for producing a film. Using a high-speed stirring mixer that can impart mechanical impact force to the core material, resin, and conductive fine particles without heating or under heating, the impact force is repeatedly applied to the mixture by high-speed stirring. A resin-coated carrier is prepared by fixing a dissolved or softened resin together with conductive fine particles on the surface. When heating, 60-125 degreeC is preferable. This is because when the heating temperature is excessive, aggregation of carrier particles tends to occur.

[Coated carrier particle size]
The volume average particle size of the coated carrier is preferably 10 to 100 μm, more preferably 20 to 80 μm. The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympatech) provided with a wet disperser.

(Carrier supply means)
The carrier supply means according to the present invention supplies the carrier contained in the developer to the surface of the organic photoreceptor, and the carrier is statically adjusted by adjusting the surface potential of the photoreceptor and the bias potential of the carrier supply means. It can be electrically supplied to the photoreceptor. Further, a bias potential difference is not provided between the photoconductor and the carrier supply means, and the physical adhesion between the photoconductor and the carrier can be supplied.

  It is particularly preferable to supply a carrier by applying a bias potential difference between the surface potential of the photoconductor and the carrier supply means because the amount of carrier supplied to the photoconductor can be adjusted more accurately.

  Next, an example of application of the carrier supply method to a reversal development method using a negatively charged photoreceptor, negatively charged toner, and positively charged carrier will be described.

  First, the surface potential when the photosensitive member is not exposed is set higher in absolute value than in a normal image forming process. That is, when the normal photoreceptor surface potential is −750V, it is set to −800V, for example.

  Next, the absolute value of the bias potential of the carrier supply means is set lower than the surface potential of the photosensitive member, and the potential difference is set larger than that during normal image formation. That is, when the surface potential of the photosensitive member at the time of carrier supply is set to -800V, the bias potential of the carrier supply means is set to -550V, for example.

  Thus, by setting the surface potential of the photoconductor and the bias potential of the carrier supply means so that the carrier is electrostatically transferred, the positively charged carrier is supplied to the photoconductor.

  The amount of carrier supplied from the carrier supply means to the photoconductor can be adjusted by the potential difference between the surface potential of the photoconductor and the bias potential of the carrier supply means, and the time for giving this potential difference.

  The potential difference between the surface potential of the photoreceptor and the bias potential of the carrier supply means is preferably 150 to 400V, and particularly preferably 170 to 300V. By setting within this range, active gases such as NOx and ozone can be effectively removed.

  The timing for supplying the carrier to the photosensitive member may be during non-image areas during image formation or during idle rotation before and after image formation. However, accumulation of active gas such as NOx and ozone stops the image forming operation. Since it is in a standby state, it is preferable immediately before the image forming operation is performed.

  Furthermore, the carrier supply operation may be performed at any time or when a predetermined state is detected. However, the influence of the active gas such as NOx and ozone on the image is particularly likely to occur in a high temperature and high humidity environment. May be detected and the execution of the carrier supply operation may be determined according to a predetermined table.

  The carrier supply unit according to the present invention is preferably used in combination with the developing unit in terms of cost and space.

  Further, it is preferable to have supply means for supplying at least one of a carrier and a two-component developer into the developing means.

(Carrier removal means)
The means for removing the carrier supplied to the photoreceptor is not particularly limited as long as the carrier can be removed, and examples thereof include a brush, a blade, and a sheet. It may also be used as a cleaning means for removing residual toner, a charging means in contact with the photosensitive member, a developing means, or the like.

  In particular, a configuration in which a fur brush and an elastic blade are used in combination, and a carrier is electrostatically removed by applying a voltage to the brush is preferable because the load on the blade is reduced.

(Developer)
Next, the developer according to the present invention will be described.

〔toner〕
As the toner used in the developer according to the present invention, a toner that is often used at present can be used without any particular limitation. That is, a styrene-acrylic resin or a polyester resin is used as the binder resin, and a typical production method such as a pulverization method or a polymerization method may be used. The particle diameter of the toner is preferably 2.0 to 8.0 [mu] m, more preferably 3.0 to 6.0 [mu] m in terms of volume-based median diameter (D50).

  Measurement of the median diameter (D50) on a volume basis is performed as follows.

  Measurement and calculation are performed using a device in which a computer system for data processing (manufactured by Beckman Coulter) is connected to "Coulter Multisizer 3" (manufactured by Beckman Coulter). As a measuring means, 0.02 g of toner was conditioned with 20 g of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant 10 times with pure water for the purpose of dispersing the toner). Thereafter, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is poured into a beaker containing ISOTON II (manufactured by Beckman Coulter) in a sample stand with a pipette until the measured concentration is 5 to 10% by mass. By setting this concentration range, a reproducible measurement value can be obtained. In the measuring machine, the measurement particle count is set to 25000, the aperture diameter is set to 50 μm, and each frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256 parts. The particle diameter of 50% from the larger volume integrated fraction is defined as the median diameter on the volume basis.

(Organic photoconductor)
Next, the organic photoreceptor according to the present invention will be described.

  The organic photoreceptor of the present invention is an organic photoreceptor having a surface layer containing at least a curable reaction product having a reactive group.

[Photosensitive layer structure]
The organic photoreceptor of the present invention is an electrophotographic photoreceptor having a photosensitive layer and a surface layer in this order on a conductive support, and the layer structure of the photosensitive layer is not particularly limited. Specifically, The following layer structure can be given.

1) Layer structure in which a charge generation layer, a charge transport layer, and a surface layer are sequentially laminated as a photosensitive layer on a conductive support.
2) A layer structure in which a single layer including both a charge transport material and a charge generation material as a photosensitive layer and a surface layer are sequentially laminated on a conductive support.
3) Layer structure in which a charge generation layer, a charge transport layer, and a surface layer are sequentially laminated as an intermediate layer and a photosensitive layer on a conductive support.
4) A layer structure in which an intermediate layer, a single layer containing a charge transport material and a charge generation material as a photosensitive layer, and a surface layer are sequentially laminated on a conductive support.

  The photoreceptor of the present invention may have any of the above-described layer structures, but among these, those prepared by providing an intermediate layer, a charge generation layer, a charge transport layer, and a surface layer on a conductive support are preferable. .

  As an application method of these intermediate layer, charge generation layer, and charge transport layer, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, etc. may be used. it can.

[Surface layer]
The surface layer of the present invention contains at least a reaction product of a curable compound having a reactive group.

[Curable compound having a reactive group]
The curable compound used in the present invention is a radically polymerizable monomer that is polymerized (cured) by irradiation with actinic rays such as ultraviolet rays and electron beams, and becomes a resin generally used as a binder resin for a photoreceptor, such as polystyrene and polyacrylate. Among the radical polymerizable monomers, styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, and N-vinyl pyrrolidone monomers are particularly preferable. Among them, an acrylic compound having an acryloyl group or a methacryloyl group is particularly preferable because it can be cured with a small amount of light or in a short time.

  The example of the curable compound concerning this invention is shown below.

In the present invention, the acrylic compound is a compound having an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═CCH ₃ CO—). In addition, the number of Ac groups (the number of acryloyl groups) described below represents the number of acryloyl groups or methacryloyl groups.

  However, in the above, R and R 'are shown below.

  Specific examples of preferable oxetane compounds as curable compounds according to the present invention are shown below.

  In the present invention, the curable compound may be a monomer or an oligomer, but the functional group is preferably 2 or more, particularly preferably 4 or more. In the acrylic compound, the ratio of the molecular weight M of the compound having an acryloyl group or methacryloyl group to the number Ac of the acryloyl group or methacryloyl group (Ac / M, number of acryloyl groups or methacryloyl groups / molecular weight) is greater than 0.005. Is preferred.

  By using an acrylic compound having an Ac / M greater than 0.005, the crosslink density is increased, the wear resistance of the photoreceptor is improved, and the occurrence of image blur and image blur can be prevented.

  As for the upper limit of Ac / M, as the value increases, the number of crosslinks in the resin increases, so the hardness of the surface layer increases and the abrasion resistance of the photoreceptor improves. However, since the hardness is too high, cracks in the surface layer or an adverse effect on the life of the coating liquid at the time of production are likely to occur, and the occurrence of image flow and image blurring may rather increase. Therefore, it is desirable that Ac / M be smaller than 0.012.

  In the present invention, two or more curable compounds having different Ac / M may be mixed and used.

[Inorganic fine particles]
Inorganic fine particles serving as a nucleus in the present invention are not particularly limited, but typical examples that are particularly frequently used include aluminum oxide (alumina: Al ₂ O ₃ ), titanium oxide (titania: TiO ₂ ), silicon oxide ( Silica: SiO ₂ ), zirconium oxide (zirconia: ZrO ₂ ), tin oxide (SnO ₂ ), zinc oxide (ZnO) and the like.

  Among these, aluminum oxide and tin oxide are particularly preferable.

  The number average primary particle size is preferably 1 to 300 nm, particularly 3 to 100 nm. If the particle size is too small, the wear resistance improvement performance is not sufficient. Conversely, if the particle size is too large, light is scattered during image writing, and photocuring is inhibited during surface layer formation. May be adversely affected.

  The number average primary particle size of the inorganic fine particles is a photographic image (excluding agglomerated particles) taken with a scanning electron microscope (manufactured by JEOL Ltd.) and a magnified photograph of 10,000 times, and 300 particles randomly taken by a scanner. ) Automatic image processing analyzer LUZEX AP (Nireco Corp.) software version Ver. The number average primary particle size was calculated using 1.32.

[Compound having polymerizable functional group used for surface treatment]
Next, the compound having a polymerizable functional group used in the present invention will be described.

  A representative example of the polymerizable functional group is a radical polymerizable functional group. Therefore, a compound having a radical polymerizable functional group is preferable, and any compound capable of covering the surface of inorganic fine particles is used in the present invention. I can do it. Among them, a particularly preferred radical polymerizable functional group in the present invention is a reactive acrylic group or a methacryl group, and a portion bonded to the surface of the inorganic fine particle so as to cover the surface of the inorganic fine particle has a structure as a silane coupling agent.

  Therefore, the compound having a polymerizable functional group that can be preferably used in the present invention is a silane coupling agent having a reactive acrylic group or methacryl group. For example, it is a compound represented by the following general formula (1).

(Wherein R ³ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aralkyl group having 1 to 10 carbon atoms, R ⁴ is an organic group having a reactive double bond, X is a halogen atom, an alkoxy group, or an acyloxy group) A group, an aminoxy group, and a phenoxy group, and n is an integer of 1 to 3.)
Examples of the compound represented by the general formula (1) will be given below.

_{S-1 CH 2 = CHSi (} CH 3) (OCH 3) 2
_{S-2 CH 2 = CHSi (} OCH 3) 3
S-3 CH ₂ = CHSiCl _{3
S-4 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5 CH 2 = CHCOO (} CH 2) 2 Si (OCH 3) 3
_{S-6 CH 2 = CHCOO (} CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7 CH 2 = CHCOO (} CH 2) 3 Si (OCH 3) 3
_{S-8 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) Cl 2
_{S-9 CH 2 = CHCOO (} CH 2) 2 SiCl 3
_{S-10 CH 2 = CHCOO (} CH 2) 3 Si (CH 3) Cl 2
S-11 CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13 CH 2 = C (} CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17 CH 2 = C (} CH 3) COO (CH 2) 2 SiCl 3
_{S-18 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19 CH 2 = C (} CH 3) COO (CH 2) 3 SiCl 3
_{S-20 CH 2 = CHSi (} C 2 H 5) (OCH 3) 2
S-21 CH ₂ ═C (CH ₃ ) Si (OCH ₃ ) _{3
S-22 CH 2 = C (} CH 3) Si (OC 2 H 5) 3
_{S-23 CH 2 = CHSi (} OCH 3) 3
_{S-24 CH 2 = C (} CH 3) Si (CH 3) (OCH 3) 2
_{S-25 CH 2 = CHSi (} CH 3) Cl 2
_{S-26 CH 2 = CHCOOSi (} OCH 3) 3
_{S-27 CH 2 = CHCOOSi (} OC 2 H 5) 3
_{S-28 CH 2 = C (} CH 3) COOSi (OCH 3) 3
_{S-29 CH 2 = C (} CH 3) COOSi (OC 2 H 5) 3
_{S-30 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
These silane compounds can be used alone or in admixture of two or more.

[Surface Treatment Method with Compound Having Polymerizable Functional Group]
Next, the surface treatment method of the inorganic fine particles using the compound having a polymerizable functional group according to the present invention will be described by taking as an example the case where the silane compound represented by the general formula (1) or the like is used. In carrying out the surface treatment, 100 parts by mass of the inorganic fine particles are treated using a wet media dispersion type apparatus using 0.1 to 200 parts by mass of a silane compound as a surface treating agent and 50 to 5000 parts by mass of a solvent. It is preferable.

  In the present invention, the surface of the inorganic fine particles is coated with a compound having a polymerizable functional group because photoelectron spectroscopy (ESCA), Auger electron spectroscopy (Auger), secondary ion mass spectrometry (SIMS), and diffusion. This is confirmed by combining surface analysis techniques such as reflection FI-IR.

  The surface treatment amount of the compound having a polymerizable functional group is obtained by heat-treating the inorganic fine particles after the surface treatment at 550 ° C. for 3 hours, quantitatively analyzing the ignition residue with fluorescent X-ray, and calculating from the Si amount to the molecular weight conversion. It is a thing.

  In the following, a surface treatment method for producing inorganic fine particles which are uniform and finely surface-treated with a silane compound will be specifically described.

  That is, the surface of the inorganic fine particles is dispersed simultaneously with the dispersion of the inorganic fine particles by wet-dispersing the slurry (solid particle suspension) containing the inorganic fine particles and the silane compound which are usually already surface-treated with the metal oxide. Processing proceeds. Thereafter, the solvent is removed to form a powder, so that inorganic fine particles that are surface-treated with a uniform and finer silane compound can be obtained.

  The wet media dispersion type apparatus, which is a surface treatment apparatus used in the present invention, is a method of agglomerating inorganic fine particles by filling beads in a container as a medium and rotating a stirring disk mounted perpendicularly to a rotation axis at high speed. It is an apparatus having a step of crushing and pulverizing / dispersing particles, and the constitution thereof is satisfactory as long as the inorganic fine particles are sufficiently dispersed and subjected to surface treatment when the surface treatment is performed on the inorganic fine particles. Various styles such as vertical, horizontal, continuous, batch, etc. can be adopted. Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. In these dispersion-type apparatuses, agglomerated particles are pulverized and dispersed by impact crushing, friction, shearing, shear stress, and the like using a pulverizing medium (media) such as balls and beads.

  As the beads used in the sand grinder mill, balls made of glass, alumina, zircon, zirconia, steel, flint stone and the like can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.3 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicon carbide are particularly used. Is preferred.

  By the wet treatment as described above, for example, inorganic fine particles subjected to the surface treatment with the silane compound of the general formula (1) can be obtained.

  The treated inorganic fine particles having a polymerizable functional group described above are formed by a reaction product resulting from a polymerization reaction with the curable compound having a reactive group, and a reaction product resulting from a mutual polymerization reaction between the treated inorganic fine particles. Can be formed.

[Additives other than the above]
The surface layer can form a cured film by applying and reacting with a coating liquid containing a polymerization initiator, lubricant particles, an antioxidant and the like, if necessary, in addition to the treated inorganic fine particles and the curable compound.

  When the surface-treated polymerizable functional group or curable compound is reacted with the inorganic fine particles of the present invention, a method of reacting by electron beam cleavage, a radical polymerization initiator or a cationic polymerization initiator is added, and light, heat The method of reacting with is used. As the polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. In the present invention, a method of performing a polymerization reaction with light or heat is particularly preferable. Further, both light and heat initiators can be used in combination.

As a radical polymerization initiator of these photocurable compounds, a photopolymerization initiator is preferable, and among them, an alkylphenone compound or a phosphine oxide compound is preferable. In particular, a compound having an α-hydroxyacetophenone structure or an acylphosphine oxide structure is preferable. The compound that initiates cationic polymerization, e.g., diazonium, ammonium, iodonium, sulfonium, aromatic onium compounds such as phosphonium ^{_{B (C 6 F 5) 4}} -, PF 6 -, AsF 6 -, SbF 6 - , CF ₃ SO ₃ ^- ionic polymerization initiator or sulfonic acid sulfonated materials that generate a such as salts, halides or generates hydrogen halide, can be mentioned nonionic polymerization initiator such as iron arene complex. In particular, a sulfonate that generates a sulfonic acid that is a nonionic polymerization initiator and a halide that generates a hydrogen halide are preferable.

  The photoinitiator used preferably below is illustrated.

  Examples of α-aminoacetophenone series

  On the other hand, as the thermal polymerization initiator, ketone peroxide compounds, peroxyketal compounds, hydroperoxide compounds, dialkyl peroxide compounds, diacyl peroxide compounds, peroxydicarbonate compounds, peroxyester compounds Compounds and the like are used, and these thermal polymerization initiators are disclosed in company product catalogs.

  In the present invention, these thermal polymerization initiators, like the above photopolymerization initiators, are treated with inorganic fine particles subjected to a surface treatment with a metal oxide and a surface treatment with a compound having a polymerizable functional group, or the polymerizability. It is mixed with a curable compound having a reactive group capable of reacting with a functional group to prepare a coating solution for the surface layer, and the coating solution is applied on the photosensitive layer and then dried by heating to relate to the present invention. A surface layer is formed. As the thermal polymerization initiator, the above-mentioned other radical polymerization initiators can be used.

  These polymerization initiators may be used alone or in combination of two or more. Content of a polymerization initiator is 0.1-20 mass parts with respect to 100 mass parts of a sclerosing | hardenable compound, Preferably it is 0.5-10 mass parts.

  The surface layer of the present invention can further contain various charge transport materials.

  The charge transport material used in the surface layer of the present invention is preferably a hole transport material having a chain polymerizable functional group, and particularly a hole transport compound having two or more chain polymerizable functional groups in the same molecule. preferable.

  Various lubricant particles can be added to the surface layer used in the present invention. For example, fluorine atom-containing resin particles can be added. Fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluorochloroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these One or two or more types are preferably selected from the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable. The ratio of the lubricant particles in the surface layer is preferably 5 to 70 parts by mass, more preferably 10 to 60% by mass with respect to 100 parts by mass of the curable compound or the inorganic oxide. The lubricant particles preferably have an average primary particle size of 0.01 to 1 μm. Particularly preferred is 0.05 to 0.5 μm. The molecular weight of the resin can be appropriately selected and is not particularly limited.

[Coating of surface layer]
In order to form the surface layer of the photocurable resin, the surface layer coating solution (the composition) is applied onto the photosensitive layer, and then primary dried to the extent that the fluidity of the coating film is lost. A method is preferred in which the surface layer is cured by irradiation, and in order to make the amount of volatile substances in the coating film a prescribed amount, secondary drying is performed.

  Solvents for forming the surface layer include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone, cyclohexane, acetic acid. Examples thereof include, but are not limited to, ethyl, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and diethylamine.

  As a coating method, known methods such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, and a slide hopper method can be used.

  In the surface layer coating method, the dip coating in which the entire photoreceptor is immersed in the surface layer coating solution increases the diffusion of the surface layer forming material to the lower layer, so that the photosensitive layer film below the surface layer is not dissolved as much as possible. It is preferable to use a coating processing method such as a circular amount regulation type (a circular slide hopper type is a typical example). The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

  The surface layer of the present invention is preferably subjected to reaction by irradiation with actinic radiation after natural drying or heat drying after coating.

  The photoreceptor of the present invention is capable of generating a cured resin by irradiating actinic rays on the coating to generate radicals and polymerizing, and curing by forming a cross-linking bond between molecules and within the molecule. preferable. As the active ray, ultraviolet rays and electron beams are particularly preferable.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 0.1 kW to 5 kW, and particularly preferably 0.5 kW to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.5 to 10 Mrad.

  The irradiation time for obtaining the necessary irradiation amount of active rays is preferably 0.1 second to 10 minutes, and more preferably 0.1 second to 5 minutes from the viewpoint of work efficiency.

  As the actinic radiation, ultraviolet rays are easy to use and are particularly preferable.

  The photoreceptor of the present invention can be dried before and after irradiating active rays and during irradiation with active rays, and the timing of drying can be appropriately selected by combining them.

  Drying conditions can be appropriately selected depending on the type of solvent, film thickness, and the like. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 ° C to 140 ° C. The drying time is preferably 1 minute to 200 minutes, and particularly preferably 5 minutes to 100 minutes.

  The film thickness of the surface layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

[Universal hardness value (HU)]
The universal hardness value (HU) of the organic photoreceptor according to the present invention is preferably 150 N / mm ² or more and 500 N / mm ² or less.

  By setting the universal hardness value (HU) within this range, the effect of removing active substances such as NOx and ozone adsorbed on the surface of the photoconductor effectively without being damaged by carrier particles is high. Become.

  The universal hardness value (HU) of the organophotoreceptor according to the present invention is defined by the following equation.

In the above equation, F is the test load (N), A (h) is the surface area (mm ² ) where the indenter is in contact with the object to be measured, and h is the indentation depth (mm) when the test load is applied. A (h) is calculated from the shape of the indenter and the indentation depth. When the indenter is a Vickers indenter, A (h) is calculated as 26.43 × h ² from the angle a (136 °) of the facing surface of the pyramidal intruder. .

<Measurement of universal hardness and plastic hardness>
The universal hardness and the plastic hardness can be measured using a commercially available hardness measuring device, for example, an ultra-micro hardness meter “H-100V” (manufactured by Fisher Instruments). be able to.

Measuring condition measuring machine: micro hardness tester "H-100V" (manufactured by Fisher Instruments)
Indenter shape: Vickers indenter (a = 136 °)
Measurement environment: 20 ° C, 60% RH
Maximum test load: 3mN
Load speed: 3mN / 20sec
Maximum load creep time: 5 seconds Unloading speed: 3 mN / 20 sec
For each sample, a total of 15 points, that is, 5 points at equal intervals in the axial direction and 3 points at equal angles in the circumferential direction, are measured, and the average value is defined as a universal hardness value (HU) defined in the present invention.

[Conductive support]
The support used in the present invention may be any one as long as it has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or a sheet, aluminum or copper Metal foils such as those laminated on plastic films, aluminum, indium oxide and tin oxide deposited on plastic films, metals with conductive layers applied alone or with a binder resin, plastic films and For example, paper.

[Middle layer]
In the present invention, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive layer and the photosensitive layer.

  The intermediate layer can be formed by dip coating or the like by dissolving a binder resin such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane and gelatin in a known solvent. Of these, an alcohol-soluble polyamide resin is preferred.

  Various conductive fine particles and metal oxides can be contained for the purpose of adjusting the resistance of the intermediate layer. For example, various metal oxides such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used.

  You may use these metal oxides 1 type or in mixture of 2 or more types. When two or more types are mixed, it may take the form of a solid solution or fusion. The average particle diameter of such a metal oxide is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  As the solvent used for the intermediate layer, a solvent in which inorganic particles are well dispersed and the polyamide resin is dissolved is preferable. Specifically, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol and the like are excellent in solubility and coating performance of the polyamide resin. In addition, examples of co-solvents that can be used in combination with the above-described solvent to obtain favorable effects in order to improve storage stability and particle dispersibility include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The density | concentration of binder resin is suitably selected according to the film thickness and production rate of an intermediate | middle layer.

  When the inorganic particles are dispersed, the mixing ratio of the inorganic particles to the binder resin at the time is preferably 20 to 400 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  As a means for dispersing the inorganic particles, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used, but is not limited thereto.

  The method for drying the intermediate layer can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  The thickness of the intermediate layer is preferably from 0.1 to 15 μm, more preferably from 0.3 to 10 μm.

(Charge generation layer)
The charge generation layer used in the present invention preferably contains a charge generation material and a binder resin, and is formed by dispersing and coating the charge generation material in a binder resin solution.

  Examples of the charge generating material include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as bilenquinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, and phthalocyanine pigments. It is not something. These charge generating substances can be used alone or in a form dispersed in a known resin.

  As the binder resin of the charge generation layer, a known resin 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 resins, phenol resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resins, chlorides) Vinyl-vinyl acetate-maleic anhydride copolymer resin) and poly-vinylcarbazole resin, but are not limited thereto.

  The charge generation layer is formed by dispersing a charge generation material in a solution in which a binder resin is dissolved in a solvent using a disperser to prepare a coating solution, and applying the coating solution to a certain film thickness using a coating device. It is preferable to prepare the film by drying.

  Solvents for dissolving and coating the binder resin used in the charge generation layer include, for example, toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, Examples include butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, and diethylamine, but are not limited thereto.

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

  The mixing ratio of the charge generating material to the binder resin is preferably 1 to 600 parts by weight, more preferably 50 to 500 parts by weight based on 100 parts by weight of the binder resin. The thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. It should be noted that the coating solution for the charge generation layer can prevent the occurrence of image defects by filtering foreign matter and aggregates before coating. The pigment can also be formed by vacuum deposition.

(Charge transport layer)
The charge transport layer used in the photoreceptor of the present invention contains a charge transport material and a binder resin, and is formed by dissolving and coating the charge transport material in a binder resin solution.

  Examples of charge transport materials include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds Oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1- Two or more kinds of vinylpyrene and poly-9-vinylanthracene may be mixed and used.

  A known resin can be used as the binder resin for the charge transport layer, and polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, and styrene-methacrylic acid. Examples include ester copolymer resins, and polycarbonate is preferred. Further, BPA, BPZ, dimethyl BPA, BPA-dimethyl BPA copolymer and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The charge transport layer is preferably formed by dissolving the binder resin and the charge transport material to prepare a coating solution, applying the coating solution to a certain film thickness with a coating machine, and drying the coating film.

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

  The mixing ratio of the charge transport material to the binder resin is preferably 10 to 500 parts by mass, more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the binder resin.

  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, and the like, but is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  An antioxidant, an electronic conductive agent, a stabilizer and the like may be added to the charge transport layer. As the antioxidant, those described in JP-A No. 2000-305291 and as the electronic conductive agent are described in JP-A Nos. 50-137543 and 58-76483.

  Next, representative embodiments of the present invention will be shown, and the configuration and effects of the present invention will be further described.

  Unless otherwise specified, “part” in the sentence represents mass part and “%” represents mass%.

(Preparation of photoreceptor 1)
A cylindrical aluminum substrate was cut to prepare a conductive support 1 having a ten-point average surface roughness Rz of 1.3 μm.

<Preparation of the intermediate layer 1>
The following intermediate layer dispersion was diluted twice with the same mixed solvent, and allowed to stand overnight, then filtered (filter; rigesh mesh filter made by Nihon Pall Co., Ltd., nominal filtration accuracy: 5 μm, pressure: 50 kPa) to prepare an intermediate layer coating solution did.

(Preparation of intermediate layer dispersion 1)
Binder resin: Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 10.0 parts Anatase-type titanium oxide (primary particle size 30 nm; surface treatment is treated with ethyltrimethoxysilane fluoride) 30.0 parts Isopropyl alcohol 100.0 parts The mixture was mixed and dispersed in a batch system for 10 hours using a sand mill disperser to prepare an intermediate layer dispersion 1.

  On the electroconductive support 1, the intermediate | middle layer coating liquid 1 was apply | coated by the dip coating method, and the intermediate | middle layer 1 with a dry film thickness of 5.0 micrometers was formed.

<Preparation of charge generation layer>
The following components were mixed and dispersed using a sand mill disperser to prepare a charge generation layer coating solution 1.

Y-form oxytitanyl phthalocyanine (Spectrum of X-ray diffraction by Cu-Kα characteristic X-ray, maximum peak angle is 27.3 ° at 2θ ± 0.2 °) 20 parts Polyvinyl butyral (# 6000-C, Denki Kagaku Kogyo Co., Ltd.) 10 parts t-butyl acetate 700 parts 4-methoxy-4-methyl-2-pentanone 300 parts This coating solution is applied by a dip coating method, and a charge of 0.8 μm in dry film thickness is generated on the intermediate layer 1. Layer 1 was formed.

<Preparation of charge transport layer>
The following components were mixed and dissolved to prepare a charge transport layer coating solution 1.

Charge transport material (4-methoxy-4 '-(4-methyl-β-phenylstyryl) triphenylamine)
75 parts Polycarbonate resin “Iupilon Z300” (Mitsubishi Gas Chemical Co., Ltd.) 100 parts 3,5-di-t-butyl-4-hydroxytoluene 2 parts Tetrahydrofuran / toluene (volume ratio 7/3) 750 parts A charge transport layer 1 having a dry film thickness of 24 μm was formed on the charge generation layer 1 by a dip coating method, and an organic photosensitive layer was produced on the conductive support.

<Preparation of surface layer>
Subsequently, a surface layer was formed by the following method.

The following charge transport material (CT-1) 30 parts 2-butyl alcohol 500 parts After dispersing the above components for 10 hours using a sand mill,
30 parts of curable compound (Exemplary Compound No. 42) 30 parts of a polymerization initiator (Exemplary Compound 1-6) were added, mixed and stirred under light shielding to dissolve, and a surface layer coating solution was prepared (light-shielding during storage).

  The surface layer was applied using a circular slide hopper coater on the organic photoreceptor on which the coating solution had been prepared up to the charge transport layer. After coating, after drying for 20 minutes at room temperature (solvent drying process), a metal halide lamp (500 W) is used for irradiation for 1 minute while rotating the photoreceptor at a position of 100 mm (ultraviolet curing process), and a surface layer having a film thickness of 3 μm To form “Photoreceptor 1”.

The universal hardness value HU of this photoconductor was 150 N / mm ² as a result of measurement under the conditions described above.

(Preparation of photoconductor 2)
The process was the same as that for the photoreceptor 1 until the charge transport layer was prepared.

<Preparation of surface layer>
Subsequently, a surface layer was formed by the following method.

Titania particles (hexamethyldisilazane treatment, number average primary particle size 30 nm) 100 parts 2-Butyl alcohol 500 parts After dispersing the above components for 10 hours using a sand mill,
30 parts of curable compound (Exemplary Compound No. 42) 30 parts of a polymerization initiator (Exemplary Compound 1-6) were added, mixed and stirred under light shielding to dissolve, and a surface layer coating solution was prepared (light-shielding during storage).

  The surface layer was applied using a circular slide hopper coater on the organic photoreceptor on which the coating solution had been prepared up to the charge transport layer. After coating, after drying for 20 minutes at room temperature (solvent drying process), a metal halide lamp (500 W) is used for irradiation for 1 minute while rotating the photoreceptor at a position of 100 mm (ultraviolet curing process), and a surface layer having a film thickness of 3 μm To form “Photoreceptor 2”.

The universal hardness value HU of this photoconductor was 198 N / mm ² as a result of measurement under the conditions described above.

(Preparation of photoreceptor 3)
The process was the same as that for the photoreceptor 1 until the charge transport layer was prepared.

<Preparation of surface layer>
Subsequently, a surface layer was formed by the following method.

  The titania particles having a number average primary particle size of 30 nm are used as the metal oxide fine particles before treatment, and the exemplified compound (S-15) is used as the surface treatment agent having a reactive organic group. Preparation of surface treatment of fine particles was performed.

  First, 100 parts of titania particles having a number average primary particle diameter of 30 nm, 5 parts of a surface treatment agent having the above reactive organic group (exemplary compound: S-15), and toluene / isopropyl alcohol = 1/1 (mass ratio). A mixed solution of 400 parts of the solvent was placed in a sand mill together with zirconia beads and stirred at about 40 ° C. at a rotational speed of 1500 rpm to perform surface treatment of titania particles. Furthermore, after taking out the said processing mixture and throwing into a Henschel mixer and stirring for 15 minutes at a rotational speed of 1500 rpm, the surface treatment of titania particles is complete | finished by drying at 120 degreeC for 3 hours, and surface-treated titania particles are obtained. It was. By the above surface treatment, the surface of the titania particles was coated with a surface treatment agent having a reactive organic group.

  Subsequently, a surface layer was formed by the following method.

Surface-treated titania particles 100 parts 2-Butyl alcohol 500 parts After dispersing the above components for 10 hours using a sand mill,
30 parts of curable compound (Exemplary Compound No. 42) 30 parts of a polymerization initiator (1-6) were added, mixed and stirred under light shielding to dissolve, and a surface layer coating solution was prepared (light shielding during storage).

  The surface layer was applied using a circular slide hopper coater on the organic photoreceptor on which the coating solution had been prepared up to the charge transport layer. After coating, after drying for 20 minutes at room temperature (solvent drying process), a metal halide lamp (500 W) is used for irradiation for 1 minute while rotating the photoreceptor at a position of 100 mm (ultraviolet curing process), and a surface layer having a film thickness of 3 μm To form “Photoreceptor 4”.

The universal hardness value HU of this photoconductor was 498 N / mm ² as a result of measurement under the conditions described above.

(Preparation of photoconductor 4)
The process was the same as that for the photoreceptor 1 until the charge transport layer was prepared.

<Preparation of surface layer>
Subsequently, a surface layer was formed by the following method.

  As the metal oxide fine particles before treatment, alumina particles having a number average primary particle diameter of 15 nm are used, and the exemplified compound (S-15) is used as a surface treatment agent having a reactive organic group. Preparation of surface treatment of fine particles was performed.

  First, 100 parts of alumina particles having a number average primary particle diameter of 30 nm, 5 parts of a surface treatment agent having the above reactive organic group (exemplary compound: S-15), and toluene / isopropyl alcohol = 1/1 (mass ratio). A mixed solution of 400 parts of the solvent was placed in a sand mill together with zirconia beads and stirred at about 40 ° C. at a rotational speed of 1500 rpm to perform surface treatment of the alumina particles. Further, the above treated mixture is taken out, put into a Henschel mixer, stirred for 15 minutes at a rotational speed of 1500 rpm, and then dried at 120 ° C. for 3 hours to finish the surface treatment of the alumina particles, thereby obtaining surface-treated alumina particles. It was. By the above surface treatment, the surface of the alumina particles was coated with a surface treatment agent having a reactive organic group.

  Subsequently, a surface layer was formed by the following method.

Surface-treated alumina particles 100 parts 2-butyl alcohol 500 parts After dispersing the above components for 10 hours using a sand mill,
Curing compound (Exemplary Compound No. 39) 30 parts Polymerization initiator (1-6) 30 parts were added, mixed and stirred under light shielding to dissolve, and a surface layer coating solution was prepared (light shielding during storage).

  The surface layer was applied using a circular slide hopper coater on the organic photoreceptor on which the coating solution had been prepared up to the charge transport layer. After coating, after drying for 20 minutes at room temperature (solvent drying process), a metal halide lamp (500 W) is used for irradiation for 1 minute while rotating the photoreceptor at a position of 100 mm (ultraviolet curing process), and a surface layer having a film thickness of 3 μm To form “Photoreceptor 3”.

The universal hardness value HU of this photoconductor was 454 N / mm ² as a result of measurement under the conditions described above.

(Preparation of photoconductor 5)
The process was the same as that for the photoreceptor 1 until the charge transport layer was prepared.

<Preparation of surface layer>
Subsequently, a surface layer was formed by the following method.

  As the metal oxide fine particles before treatment, tin oxide particles having a number average primary particle diameter of 20 nm are used, and the exemplified compound (S-29) is used as a surface treatment agent having a reactive organic group. Preparation of surface treatment of physical particles was performed.

  First, 100 parts of tin oxide particles having a number average primary particle diameter of 30 nm, 10 parts of a surface treatment agent having the above reactive organic group (exemplary compound: S-29), toluene / isopropyl alcohol = 1/1 (mass ratio). A mixed solution of 400 parts of the mixed solvent was put in a sand mill together with zirconia beads and stirred at about 40 ° C. at a rotational speed of 1500 ppm to perform surface treatment of the tin oxide particles. Further, the treated mixture is taken out, put into a Henschel mixer, stirred for 15 minutes at a rotational speed of 1500 rpm, and then dried at 120 ° C. for 3 hours to finish the surface treatment of the tin oxide particles, and the surface-treated tin oxide particles Got. By the above surface treatment, the surface of the tin oxide particles was coated with a surface treatment agent having a reactive organic group.

  Subsequently, a surface layer was formed by the following method.

Surface-treated tin oxide particles 100 parts 2-butyl alcohol 500 parts After dispersing the above components for 10 hours using a sand mill,
30 parts of curable compound (Exemplary Compound No. 43) 30 parts of a polymerization initiator (1-6) were added, mixed and stirred under light shielding to dissolve, and a surface layer coating solution was prepared (light shielding during storage).

  The surface layer was applied using a circular slide hopper coater on the organic photoreceptor on which the coating solution had been prepared up to the charge transport layer. After coating, after drying for 20 minutes at room temperature (solvent drying process), a metal halide lamp (500 W) is used for irradiation for 1 minute while rotating the photoreceptor at a position of 100 mm (ultraviolet curing process), and a surface layer having a film thickness of 3 μm To form “Photoreceptor 5”.

The universal hardness value HU of this photoconductor was 402 N / mm ² as a result of measurement under the conditions described above.

(Preparation of photoreceptor 6)
The process was the same as that for the photoreceptor 1 until the charge transport layer was prepared.

<Preparation of surface layer>
A surface layer was formed in the same manner except that the charge transport material (CT-1) was changed from 30 parts to 60 parts in the production of the photoconductor 1 to produce “photoreceptor 6”.

The universal hardness value HU of this photoconductor was 136 N / mm ² as a result of measurement under the conditions described above.

(Preparation of photoconductor 7)
The process was the same as that for the photoreceptor 1 until the charge transport layer was prepared.

<Preparation of surface layer>
A surface layer was formed in the same manner as in the production of the photoreceptor 4 except that the electrofinished alumina particles were changed from 100 parts to 300 parts, and "Photoreceptor 7" was produced.

The universal hardness value HU of this photoconductor was 534 N / mm ² as a result of measurement under the conditions described above.

(Preparation of photoconductor 8)
The process was the same as that for the photoreceptor 1 until the charge transport layer was prepared.

<Preparation of surface layer>
Subsequently, a surface layer was formed by the following method.

  A liquid in which the following components are mixed is dispersed for 10 hours using a batch-type sand mill disperser, and then filtered (filter: rigesh mesh filter manufactured by Nihon Pall Co., Ltd., nominal filtration accuracy: 5 μm, pressure: 50 kPa) and applied to the surface layer. A liquid was prepared.

Charge transport material (4-methoxy-4 ′-(4-methyl-β-phenylstyryl) triphenylamine) 70 parts by weight Polycarbonate resin “Iupilon Z500” (Mitsubishi Gas Chemical Co., Ltd.) 100 parts by weight 3,5-di- t-Butyl-4-hydroxytoluene 8 parts by mass Tetrahydrofuran 1000 parts by mass Inorganic fine particle “silica” (number average primary particle size 0.033 μm) 20 parts by mass The above surface layer coating solution is applied to a circular slide hopper coating apparatus on the charge transport layer Then, the film was dried at 110 ° C. for 60 minutes to form a surface layer having a dry film thickness of 6 μm, thereby producing “Photoreceptor 8”.

The universal hardness value HU of this photoconductor was 118 N / mm ² as a result of measurement under the conditions described above.

(Configuration of image forming apparatus)
The image forming apparatus used was a bizhub PRO C6500 remodeling machine (negatively charged charging potential, laser exposure / reverse development / intermediate tandem color compound machine) manufactured by Konica Minolta Business Technologies, Inc. having the following configuration.

Photosensitive drum: The above photosensitive members 1 to 8
Photoconductor unexposed potential: -750V
(Controllable range: -250V to -900V: Detected by potential sensor and feedback control)
Photoreceptor exposure potential: -100V (Settable range: -45 to 150V)
Exposure: Laser scanning method: Semiconductor laser with a wavelength of 780 nm Development DC bias: -600 V (controllable range: -200 to -700 V)
Development AC bias: -0.75 kVp-p, 4 kHz
(Controllable range: 0.5 to -2.0 kVp-p, 2 to 7 kHz)
Carrier supply means: Development DC bias cleaning blade: 2 mm thick polyurethane rubber blade Blade contact force: 23 N / m
Cleaning auxiliary brush: shaft outer diameter 6mm, brush outer diameter 12mm
Brush configuration: conductive nylon fiber, thickness 6 denier, flocking density 100,000 / inch ² , brush hair length 2.5mm
(Developer composition)
Carrier: Mn—Mg ferrite core particles having a volume average particle size of 35 μm, carbon black (Mogul-L, manufactured by CABOT, average particle size 24 nm, electric resistance: 10 ⁻² Ω · cm) 5.0 parts by mass and styrene / methyl 2.0 parts by mass of copolymer resin fine particles of methacrylate (copolymerization ratio 2/8) are put into a high-speed mixer equipped with stirring blades, stirred and mixed at 120 ° C. for 60 minutes, and ferrite is applied by the action of mechanical impact force. A resin layer having a layer thickness of 0.5 μm was formed on the surface of the core particle.

  Toner: Y (yellow), M (magenta), C (cyan), K (volume median diameter (Dv50) of 6.2 μm with reference to the emulsion polymerization method described in JP-A-2007-57774, etc. Black) four types of base particle toners (toners before addition of external additives) were prepared.

  To 100 parts by mass of the mother particle toner, 0.5 part by mass of hydrophobic silica having a number average particle diameter of 15 nm and 1.0 part by mass of hydrophobic titanium oxide having a number average particle diameter of 50 nm are added. After adding 14 parts by mass, each toner was sufficiently stirred with a Henschel mixer to prepare Y toner, M toner, C toner, and K toner.

  Developer: A developer was prepared by mixing so that the toner concentration with respect to the carrier was 6% by mass.

Example 1
After mounting the photoconductor 1 and the above conditions, first set the environmental conditions to 30 ° C. and 80% RH, add 50,000 actual shooting histories to neutral paper with A4 images with each color printing rate of 5%, and after printing is completed The main power supply of the image forming apparatus was stopped in 60 seconds.

  After 12 hours from the stop, the power was turned on to enable printing. At this time, the photosensitive member was set so as not to rotate.

<Carrier supply process>
Next, the photosensitive member unexposed potential is set to -800 V, the development DC bias is set to -550 V, and the carrier is supplied to the photosensitive member, so that the potential is output in synchronization with the rotational driving of the photosensitive member. did.

  At this time, the cleaning blade and the cleaning auxiliary brush were removed.

  The rotating operation of the photosensitive member was performed for 30 seconds under the above conditions while supplying the carrier to the photosensitive member. At this time, the intermediate transfer member was retracted from the photosensitive member and brought into a non-contact state.

<Carrier removal process>
Further, the photosensitive member unexposed potential is set to -750 V and the developing DC bias is set to normal values of -600 V, the photosensitive member is rotated by one rotation, and the carrier supplied to the photosensitive member is recovered again to the developing means, and the carrier from the photosensitive member is recovered. Was removed.

  If this carrier removal step is not performed, the carrier adheres to the intermediate transfer member or the output medium during image formation, resulting in an abnormal image such as a spot-like defect.

  Immediately after that, the printer was made ready for printing with normal settings, and a 6-dot lattice image of the entire surface of A3 was printed on the entire surface of A3 neutral paper.

(Performance evaluation)
<Image blur>
The state of the printed image was observed, and the dot reproducibility image flow was visually evaluated in five stages.

◎: Each dot is independently formed on the image, and very good image quality characteristics ○: Approximately 80% of the dots on the image are independently formed, and good image quality characteristics △: On the image About 70% of the dots are formed independently, and there is no practical problem. X: Independence of about 50% or more dots on the image is insufficient and cannot be used practically.
Next, the photoconductor was taken out from the image forming apparatus, the surface state of the photoconductor was observed, and the state of the scratch was evaluated. The evaluation photoconductor was evaluated by installing it at the cyan position.

A: No surface scratch (very good)
○: 1 to 3 surface scratches (good)
Δ: Surface scratches occurred at 4 to 10 points (no problem in practical use)
×: 11 or more surface flaws (practical problems)
(Example 2)
In Example 1, the same operation was performed until the recording history of 50,000 sheets and the stop for 12 hours.

<Carrier supply process and carrier removal process>
Next, the photosensitive member unexposed potential is set to -800 V, the development DC bias is set to -550 V, and the carrier is supplied to the photosensitive member, so that the potential is output in synchronization with the rotational driving of the photosensitive member. did.

  At this time, with the cleaning blade attached, only the cleaning auxiliary brush was removed, and the carrier supplied to the photosensitive member could be removed using the blade.

  The rotating operation of the photosensitive member was performed for 30 seconds under the above conditions while supplying the carrier to the photosensitive member.

  Immediately after that, the printer was made ready for printing with normal settings, and a 6-dot lattice image of the entire surface of A3 was printed on the entire surface of A3 neutral paper.

(Example 3)
In Example 1, the same operation was performed until the recording history of 50,000 sheets and the stop for 12 hours.

<Carrier supply process and carrier removal process>
Next, the photosensitive member unexposed potential is set to -800 V, the development DC bias is set to -550 V, and the carrier is supplied to the photosensitive member, so that the potential is output in synchronization with the rotational driving of the photosensitive member. did.

  At this time, with the cleaning auxiliary brush attached, only the cleaning blade was removed, and the carrier supplied to the photosensitive member could be removed with the cleaning auxiliary brush. In addition, -200 V was applied to the cleaning auxiliary brush in synchronism with the rotation of the photosensitive member in order to electrostatically recover the carrier from the photosensitive member.

  The rotating operation of the photosensitive member was performed for 30 seconds under the above conditions while supplying the carrier to the photosensitive member.

  Immediately after that, the printer was made ready for printing with normal settings, and a 6-dot lattice image of the entire surface of A3 was printed on the entire surface of A3 neutral paper.

Example 4
In Example 1, the same operation was performed until the recording history of 50,000 sheets and the stop for 12 hours.

<Carrier supply process and carrier removal process>
Next, the photosensitive member unexposed potential is set to -800 V, the development DC bias is set to -550 V, and the carrier is supplied to the photosensitive member, so that the potential is output in synchronization with the rotational driving of the photosensitive member. did.

  At this time, the cleaning blade and the cleaning auxiliary brush are mounted, and the carrier supplied to the photosensitive member can be removed using both the cleaning blade and the cleaning auxiliary brush. In addition, -200 V was applied to the cleaning auxiliary brush in synchronism with the rotation of the photosensitive member in order to electrostatically recover the carrier from the photosensitive member.

  The rotating operation of the photosensitive member was performed for 30 seconds under the above conditions while supplying the carrier to the photosensitive member.

  Immediately after that, the printer was made ready for printing with normal settings, and a 6-dot lattice image of the entire surface of A3 was printed on the entire surface of A3 neutral paper.

(Example 5)
In Example 4, the evaluation was performed in the same manner except that the photoreceptor 1 was replaced with the photoreceptor 2.

(Example 6)
In Example 4, the evaluation was carried out in the same manner except that the photosensitive member 1 was replaced with the photosensitive member 3.

(Example 7)
In Example 4, the evaluation was performed in the same manner except that the photosensitive member 1 was replaced with the photosensitive member 4.

(Example 8)
In Example 4, the evaluation was performed in the same manner except that the photosensitive member 1 was replaced with the photosensitive member 5.

Example 9
In Example 4, the evaluation was performed in the same manner except that the photosensitive member 1 was replaced with the photosensitive member 6.

(Example 10)
In Example 4, the evaluation was performed in the same manner except that the photosensitive member 1 was replaced with the photosensitive member 7.

(Comparative Example 1)
In Example 4, the actual shooting history of 50,000 sheets under the environmental conditions of 30 ° C. and 80% RH was added, and after 12 hours from the stop, the power was turned on to enable printing, and then the carrier supply operation was not performed for 30 seconds. Evaluation was carried out in the same manner except that the photoreceptor was simply idled.

  In this experiment, since the carrier is supplied, the carrier removal step is not necessary.

(Comparative Example 2)
In Example 4, the evaluation was performed in the same manner except that the photosensitive member 1 was replaced with the photosensitive member 8.

  The evaluation results of Examples 1 to 10 and Comparative Examples 1 and 2 are shown in Table 1.

  Inorganic fine particles: “Finished” refers to those that have been surface treated with a compound having a polymerizable functional group.

  In Examples 1 to 10 in the present invention, all the characteristics are within the practical range, but it can be seen that Comparative Examples 1 and 2 outside the present invention have problems in at least any of the characteristics.

1,1Y, 1M, 1C, 1K Image carrier (photosensitive member)
4,4Y, 4M, 4C, 4K Developing device 41 Developing roller 41A Developing sleeve (developer carrier)
41B Magnetic field generation means (magnet roll)
A color image forming apparatus N1 main developing magnetic pole N4, S1, S2, S3 magnetic pole (developer conveying magnetic pole)

Claims (7)

  An organic photoreceptor, a charging means for charging the photoreceptor, an exposure means for exposing the charged photoreceptor surface to form an electrostatic latent image, and a two-component containing the electrostatic latent image with toner and a carrier In the image forming apparatus having at least a developing unit that develops a visible image by developing with a developer, the photoreceptor includes a surface layer containing a reaction product of a curable compound having at least a reactive group. And a carrier supply unit that supplies a carrier to the surface of the photoconductor and a carrier removal unit that removes the carrier supplied to the surface of the photoconductor, and is operated outside the time of image formation. An image forming apparatus.   The image forming apparatus according to claim 1, wherein the carrier supply unit is a developing unit.   The image forming apparatus according to claim 1, wherein the carrier removing unit is a cleaning unit.   The image forming apparatus according to claim 3, wherein the cleaning unit is configured to use a brush and a blade together.   The image forming apparatus according to claim 1, wherein the surface layer of the organophotoreceptor contains inorganic fine particles.   The image forming apparatus according to claim 5, wherein the inorganic fine particles are surface-treated with a compound having a polymerizable functional group. The image forming apparatus according to claim 1, wherein a universal hardness value (HU) of the organic photoreceptor is 150 N / mm ² or more and 500 N / mm ² or less.

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