JP2012150390A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that forms high-quality images for a long period of time while sufficiently utilizing the performance of an organic electrophotographic photoreceptor with high durability.SOLUTION: There is provided an image forming apparatus including: polishing means for polishing the surface of a photoreceptor; polishing force adjustment means for adjusting polishing force of the polishing means; and control means for controlling the polishing force adjustment means.

Description

  The present invention relates to an electrophotographic image forming apparatus.

  Electrophotographic image forming apparatuses have been used in a wider range of applications, such as being used in the field of printing due to their high speed performance.

  With the increase in the speed of electrophotographic image forming apparatuses, there is an increasing need for highly durable image forming apparatuses, that is, image forming apparatuses that increase the number of images that can be formed during a durable period.

  As a technique necessary for enhancing the durability of the apparatus, there is a technique for enhancing the durability of the photoreceptor.

  In the organic photoreceptor, high durability is realized by providing a protective layer on the surface of the photoreceptor.

  In Patent Document 1, a tin oxide particle having a reactive acryloyl group or methacryloyl group is reacted with a curable monomer having a reactive methacryloyl group and a functional group density of the reactive methacryloyl group greater than 0.005. An organic electrophotographic photosensitive member having a protective layer made of a composition obtained by the above process is disclosed.

  The organic electrophotographic photoreceptor of Patent Document 1 has the same durability as the amorphous silicon photoreceptor.

  On the other hand, techniques for controlling a cleaning brush have been developed for the purpose of preventing image defects called image flow and improving cleaning performance.

  In Patent Document 2, it is proposed to control the cleaning unit in accordance with the image density in order to prevent a deterioration in the cleaning performance of the cleaning unit including a cleaning brush.

  Patent Document 3 proposes supplying toner to a cleaning device in an image forming apparatus using an amorphous silicon photoreceptor in order to prevent image flow caused by ozone products generated during charging.

  In Patent Document 4, it is proposed to control the rotation speed of a rotating brush that rubs the surface of the photoreceptor in order to remove discharge products on the surface of the photoreceptor.

JP 2010-152338 A JP 2006-276065 A JP 2003-330319 A JP 2005-266448 A

  The photoreceptor of Patent Document 1 is an organic photoreceptor having high durability. However, the photoreceptor of Patent Document 1 cannot fully utilize the performance of the photoreceptor depending on the conditions under which it is used, and it is difficult to maintain high image quality and extend durability.

  In Patent Documents 2 to 4, the cleaning brush for cleaning the photoconductor is controlled, but the photoconductor proposed in Patent Document 1 is used only by improving the cleaning performance and removing the discharge products. In image formation, it is not possible to sufficiently ensure high image quality and photoreceptor durability.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which a high-quality image is formed and a highly durable photoconductor is mounted by fully utilizing the performance of the photoconductor disclosed in Patent Document 1. .

  The object is achieved by the following invention.

1. Tin oxide particles having a reactive acryloyl group or a methacryloyl group, a reactive methacryloyl group, and the formula {functional group density of the reactive methacryloyl group = (the number of reactive methacryloyl groups) / (of the curable monomer) (Molecular weight)}, a photoconductor comprising an organic electrophotographic photoconductor having a protective layer comprising a composition obtained by reacting a reactive methacryloyl group having a functional group density of greater than 0.005. When,
Toner image forming means for forming a toner image on the photoreceptor;
A transfer device for transferring the toner image on the photosensitive member to a transfer member;
An image forming apparatus comprising: a cleaning device that cleans the photoconductor after transfer, and a cleaning device that includes a polishing unit that polishes the surface of the photoconductor.
An image forming apparatus comprising: a polishing force adjusting unit that adjusts a polishing force of the polishing unit; and a control unit that controls the polishing force adjusting unit.

2. An environmental sensor that detects temperature and humidity;
Paper type information generating means for generating information on the type of transfer member;
Printing rate information generating means for generating printing rate information of an image to be formed;
Photoconductor history information generating means for generating information on the history of the photoconductor;
Having at least one of polishing history information generating means for generating history information of the polishing means,
The control means includes at least one of the environmental sensor, the paper type information generation means, the printing rate information generation means, the photoconductor history information generation means, and the polishing history information generation means. 2. The image forming apparatus according to 1, wherein the polishing force adjusting unit is controlled based on information.

3. The polishing force adjusting means includes
A speed difference adjusting means for adjusting a difference between a surface speed of the photoconductor and a surface speed of the polishing means;
Forming toner amount adjusting means for adjusting the amount of toner for forming a toner image for photoconductor polishing formed on the photoconductor;
A toner movement amount adjusting unit that adjusts a voltage between the photoconductor and the polishing unit to adjust an amount of toner that moves from the photoconductor to the polishing unit;
3. The image forming apparatus according to 1 or 2, further comprising at least one of a toner removal amount adjusting unit that adjusts an amount of toner removed from the polishing unit.

4). The transfer device transfers a toner image to the transfer body made of a recording material,
The control means controls the polishing force adjusting means based on a combination of information from the environmental sensor, information from the paper type information generating means, and information from the printing rate information generating means. 4. The image forming apparatus as described in 2 or 3 above.

5. The transfer body is an intermediate transfer body,
The image according to (2) or (3), wherein the control unit controls the polishing force adjusting unit based on a combination of information from the environmental sensor and information from the printing rate information generating unit. Forming equipment.

6). Having a potential sensor that detects an exposure potential that is a potential when the charged photoreceptor is exposed to a predetermined amount of light;
2. The image forming apparatus according to 1, wherein the control unit controls the polishing force adjusting unit based on information from the potential sensor.

7). An environmental sensor that detects temperature and humidity;
Photoconductor history information generating means for generating information on the history of the photoconductor;
Having at least one of polishing history information generating means for generating history information of the polishing means,
The control means controls the polishing force adjusting means based on information from at least one of the environmental sensor, the photoreceptor history information generating means, and the polishing history information generating means. The image forming apparatus according to 6 above.

  In the present invention, a tin oxide particle having a reactive acryloyl group or a methacryloyl group is reacted with a curable monomer having a reactive methacryloyl group and a functional group density of the reactive methacryloyl group greater than 0.005. By using a photoconductor having a protective layer made of the composition obtained and controlling the polishing power adjusting means, the polishing power on the surface of the photoconductor is appropriately adjusted. Thereby, the durability of the photoconductor is fully utilized, and a highly durable image forming apparatus capable of forming a high-quality image over a long period of time is realized.

1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram showing a configuration of a cleaning device 27. It is a graph which shows an example of the relationship between the exposure potential of the photoreceptor which has a protective layer, and the film thickness of a protective layer. It is a graph which shows the relationship between image quality and a photoreceptor, and the abrasion parameter | index alpha. FIG. 4 is a diagram illustrating a toner band formed on a photosensitive member 21 for polishing the photosensitive member. It is a figure which shows the adjustment means of a voltage. It is a figure which shows the change of the polishing power of a cleaning brush. It is a block diagram of a control system for controlling the polishing force adjusting means. It is a block diagram of a control system for controlling the polishing force adjusting means. It is a figure which shows arrangement | positioning of an electric potential sensor. It is a figure which shows the image forming apparatus which concerns on Embodiment 3 of this invention.

  Hereinafter, the present invention will be described based on an embodiment of the present invention, but the present invention is not limited to the embodiment.

[Embodiment 1]
<Image forming apparatus>
An image forming apparatus 1 shown in FIG. 1 is a cross-sectional configuration diagram of a digital image forming apparatus, and includes a document conveying device A, an image reading unit B, an image forming unit C, and a recording material conveying unit D.

  In the automatic document feeder A, the document placed on the document table 11 is separated and conveyed by the document conveying roller 12 and the image is read at the reading position 13a. After the document reading is completed, the document is discharged onto the document discharge tray 14 by the document transport roller 12.

  The image reading unit B includes a platen glass 13, an optical system 15 including a mirror and a lens, and an image sensor 16 including an OOD, and reads an original conveyed by the automatic original conveying apparatus A or an original on the platen glass 13.

  The image forming unit C includes a drum-shaped photoconductor 21, around the photoconductor 21, a toner image forming unit including a charging device 22, an exposure device 23, and a developing device 24, a transfer device 25, and a separation device 26. A cleaning device 27 is arranged. The rotating photoconductor 21 is uniformly charged by the charging device 22, and then the exposure device 23 performs image exposure based on the image signal. The electrostatic latent image on the photoconductor 21 is reversely developed by the developing device 24, and a visible toner image is formed on the surface of the photoconductor 21. In the image forming method of the present invention, it is preferable to use a polymerized toner as a developer used for development. By using a polymer toner having a uniform shape and particle size distribution in combination with the organic photoreceptor according to the present invention, an electrophotographic image with better sharpness can be obtained.

  In the recording material transport unit D, three sheet feeding trays 41 are provided as recording material storing means in which recording materials P of different sizes are stored in the lower part of the apparatus, and manual feeding is performed on the side for manual feeding. A recording material P selected from any one of them is transported on a transport path 40 by a transport roller 43, and a recording material P is corrected by a pair of registration rollers 44 that correct the tilt and bias of the recording material P. The paper P is temporarily stopped and then re-feeded. The toner image is transferred by the transfer device 25 and the separation device 26, and the recording material P is separated from the photoreceptor 21. The separated recording material P is transported by the transfer transport belt device 45 and sent to the fixing device 50.

  The fixing device 50 includes a fixing roller 51 and a pressure roller 52. The recording material P is passed between the fixing roller 51 and the pressure roller 52 to fix the toner image by heating and pressing. . The recording material P after the fixing process is discharged onto a paper discharge tray 64 of the paper discharge conveyance unit 60.

  The above describes the state in which image formation is performed on one side of the recording material P. However, in the case of double-sided copying, the recording material P is conveyed below the paper discharge conveyance unit 60 by a paper discharge switching member (no reference numeral). It is conveyed to the path 61.

  The recording material P is further transferred from the refeed unit 62 to the transfer position after being switched back by the reversing unit 63 and turned upside down. Then, after the toner image is transferred to the back surface of the recording material P by the transfer device 25 and fixed by the fixing device 50, the recording material P is discharged to the paper discharge tray 64.

  The image forming apparatus of the present invention is constructed by integrally connecting components such as the photosensitive member 21, the developing device 24, and the cleaning device 27 as a process cartridge, and this unit is configured to be detachable from the apparatus main body. Also good.

  VS is a potential sensor that detects the potential of the photosensitive member 21.

<Developer>
The electrostatic latent image formed on the organic photoreceptor of the present invention is visualized as a toner image by development. The toner used for development may be a pulverized toner or a polymerized toner, but a polymerized toner prepared by a polymerization method is preferred from the viewpoint of obtaining a stable particle size distribution.

  The polymerized toner means a toner whose toner shape is formed by polymerization of a raw material monomer of a binder resin and, if necessary, subsequent chemical treatment. More specifically, it means a toner formed through a polymerization reaction such as suspension polymerization or emulsion polymerization, and if necessary, a step of fusing particles between them.

  The volume average particle diameter of the toner, that is, the 50% volume particle diameter (Dv50) is preferably 2 to 9 μm, more preferably 3 to 7 μm. By setting this range, the resolution can be increased. In addition, by combining with the above range, the amount of toner having a fine particle diameter can be reduced while being a small particle diameter toner, the dot image reproducibility is improved over a long period of time, and the sharpness is excellent. In addition, a stable image can be formed.

  The toner used in the present invention may be used as a one-component developer or a two-component developer.

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.

  Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 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 SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are 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, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.

  The toner contains an abrasive.

  The abrasive is a fine particle having a particle diameter of 0.1 to 1.0 μm added to the toner. Examples of the abrasive preferably used include various inorganic particles and organic fine particles. The viewpoint of polishing the protective layer of the photoreceptor. To inorganic particles are preferred. For example, titanium oxide, strontium titanate, barium titanate, calcium titanate, cerium oxide and the like can be preferably used. These inorganic particles may have a hydrophobic surface. The addition amount is preferably 0.1 to 3.0% by mass in the toner (here, the total mass of the toner indicates the total mass including fine particles), more preferably 0.1 to 2.0% by mass. %. If this range is exceeded, the polishing effect of the protective layer of the photoreceptor increases, but the polishing power becomes too strong and the durability of the photoreceptor decreases. On the other hand, if it is too small, the effect of removing the discharge products on the photoreceptor is lowered, and the image quality such as image flow is lowered.

<Photoconductor>
For example, a film having higher hardness than that of the monomer can be generated by using a reactive tin oxide and a photo-curing acrylic resin and making the acrylic monomer a high molecular weight oligomer having a molecular weight of 1000 or more. However, there is a problem that image blur and image flow are likely to occur, and it has not been a solution for improving image quality.

  In the present invention, it has been found that by reacting a monomer having a low molecular weight and a large number of functional groups, that is, a monomer having a large reactive group equivalent and a reactive tin oxide, the hardness can be increased as compared with an oligomer having a molecular weight of 1000 or more. In this case, the purpose can be more achieved by using a self-cleaving type polymerization initiator as an initiator if necessary.

In addition, a cured film obtained by curing a monomer having a methacryloyl group is less likely to cause image blur due to NOx adsorption than a cured film obtained by curing a monomer having an acryloyl group. On the other hand, since the reactivity is poor, there is a problem that the film hardness cannot be obtained. However, when a monomer having a methacryloyl group and a tin oxide particle (SnO ₂ ) having a reactive acryloyl group or a methacryloyl group as a polymerizable unsaturated group are reacted as in the present invention, SnO ₂ has a low refractive index, and thus is UV-cured. In this case, the film transmits UV light well, and the monomer is sufficiently irradiated with UV light to promote polymerization, so that a cured film harder than other cured films using metal oxides with a high refractive index can be obtained. It was.

[Tin oxide particles having reactive acryloyl group or methacryloyl group]
The tin oxide particles having a reactive acryloyl group or methacryloyl group used in the present invention will be described.

  The tin oxide particles having a reactive acryloyl group or methacryloyl group used in the present invention can be produced, for example, by reacting a compound represented by the following general formula (1) with tin oxide particles.

(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 acryloyl group or methacryloyl group, X is a halogen atom, an alkoxy group) An acyloxy group, an aminoxy group, or 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 = CHCOO (} CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-2 CH 2 = CHCOO (} CH 2) 2 Si (OCH 3) 3
_{S-3 CH 2 = CHCOO (} CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-4 CH 2 = CHCOO (} CH 2) 3 Si (OCH 3) 3
_{S-5 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) Cl 2
_{S-6 CH 2 = CHCOO (} CH 2) 2 SiCl 3
_{S-7 CH 2 = CHCOO (} CH 2) 3 Si (CH 3) Cl 2
_{S-8 CH 2 = CHCOO (} CH 2) 3 SiCl 3
_{S-9 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-10 CH 2 = C (} CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-11 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-12 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-13 CH 2 = C (} CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-14 CH 2 = C (} CH 3) COO (CH 2) 2 SiCl 3
_{S-15 CH 2 = C (} CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-16 CH 2 = C (} CH 3) COO (CH 2) 3 SiCl 3
_{S-17 CH 2 = CHCOOSi (} OCH 3) 3
_{S-18 CH 2 = CHCOOSi (} OC 2 H 5) 3
_{S-19 CH 2 = C (} CH 3) COOSi (OCH 3) 3
_{S-20 CH 2 = C (} CH 3) COOSi (OC 2 H 5) 3
_{S-21 CH 2 = C (} CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-22 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-23 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-24 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-25 CH 2 = CHCOO (} CH 2) 2 Si (CH 3) (OC 6 H 5) 2
_{S-26 CH 2 = CHCOO (} CH 2) 2 Si (C 10 H 21) (OCH 3) 2
_{S-27 CH 2 = CHCOO (} CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2
These silane compounds can be used alone or in admixture of two or more.

[Method for producing tin oxide particles having a reactive group]
The tin oxide particles having a reactive acryloyl group or methacryloyl group according to the present invention can be obtained by surface-treating the tin oxide particles using the silane compound represented by the general formula (1) or the like. In carrying out the surface coating treatment, 0.1-100 parts by mass of a silane compound as a surface treatment agent and 50-5000 parts by mass of a solvent are used with 100 parts by mass of tin oxide particles, using a wet media dispersion type apparatus. It is preferable to do.

  The following describes a surface treatment method for producing tin oxide particles that are uniform and more finely surface-coated with a silane compound.

  That is, by subjecting a slurry (suspension of solid particles) containing tin oxide particles and a silane compound to wet pulverization, the surface treatment of the tin oxide particles proceeds at the same time as the tin oxide particles are refined. Thereafter, since the solvent is removed to form powder, tin oxide 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 an aggregated particle of alumina by filling beads in a container as a medium and rotating a stirring disk mounted perpendicularly to the rotation axis at high speed. Is a device having a step of crushing and pulverizing / dispersing, and as a configuration thereof, there is no problem if the tin oxide particles are sufficiently dispersed and subjected to surface treatment when the surface treatment is performed on the tin oxide particles, for example, Various styles such as vertical type, horizontal type, continuous type and batch type 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. These dispersion-type devices are pulverized and dispersed by impact crushing, friction, shearing, shear stress, etc., using a grinding 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, tin oxide particles having a reactive acryloyl group or methacryloyl group can be obtained by surface treatment with the silane compound of the general formula (1).

  Here, having a reactive acryloyl group or methacryloyl group means that the hydroxyl group on the surface of the metal oxide particle and the alkoxysilane compound form a chemical bond by a hydrolysis reaction.

  Thereby, the reactive organic group in the silane compound such as the general formula (1) becomes metal oxide particles present on the particle surface.

  The tin oxide particles having the reactive group form a protective layer by reaction with the compound having a polymerizable group according to the present invention described below.

[Curable monomer having a reactive methacryloyl group]
A curable monomer having a reactive methacryloyl group, that is, a compound that reacts with the reactive acryloyl group or methacryloyl group of the tin oxide particles (sometimes referred to as a curable compound) is used.

  In the present invention, these curable compounds according to the present invention may be used alone or in combination.

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

In the present invention, the methacryloyl compound is a compound having a methacryloyl group (CH ₂ ═C (CH ₃ ) CO—). Moreover, the number of Ac groups referred to below represents the number of methacryloyl groups.

  However, in the above, R is shown below.

  In the present invention, the curable compound preferably has 2 or more functional groups. The methacryloyl-based compound is a compound in which the ratio of the molecular weight M of the compound having a methacryloyl group to the number Ac of the methacryloyl group (Ac / M, the number of methacryloyl groups / molecular weight) is greater than 0.005.

  By using a curable monomer 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 drift 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 protective layer increases and the wear resistance of the photoreceptor improves. However, since the hardness is too high, the protective layer is cracked or the life of the coating solution during production tends to be adversely affected, and the occurrence of image flow and image blurring tends to increase. Therefore, it is rather desirable that Ac / M is smaller than 0.05. Further, Ac / M is particularly preferably 0.01 or less.

  In the present invention, two or more curable compounds having different functional group densities may be mixed and used.

[Tin oxide particles]
As the tin oxide particles used in the present invention, those produced by a general production method such as a known method, for example, a gas phase method, a chlorine method, a sulfuric acid method, a plasma method, or an electrolytic method are used. In particular, particles produced by the plasma method are preferable because fine and homogeneous particles having a narrow particle size distribution and few aggregated particles and having relatively uniform crystal habit can be obtained.

  The shape of the tin oxide particles used in the present invention may be spherical or irregular, and the surface may be smooth or uneven, but spherical particles having a smooth surface are preferred because the surface treatment can be made uniform.

  The number average primary particle size of the tin oxide particles used in the present invention is in the range of 1 to 300 nm, particularly preferably 3 to 100 nm. When the particle size is small, the wear resistance is not sufficient, and when the particle size is large, writing light may be scattered, or the particles may hinder photocuring and the wear resistance may be insufficient.

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

  The ratio of the tin oxide particles in the protective layer is 1 to 200 parts by mass, particularly preferably 50 to 180 parts by mass with respect to 100 parts by mass of the curable compound.

[Additives other than the above, other]
In addition to the curable compound and tin oxide particles, the protective layer can be coated with a coating solution containing a polymerization initiator, lubricant particles, an antioxidant, and the like, if necessary, and reacted to form a cured film.

  When the curable compound of the present invention is reacted, a method of reacting by electron beam cleavage, a radical polymerization initiator, a method of reacting with light or heat, or the like is used. As the polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. 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 photoinitiator used preferably below is illustrated.

  Examples of α-aminoacetophenone series

  Examples of α-hydroxyacetophenone compounds

  Examples of acylphosphine oxide compounds

  Examples of other radical polymerization initiators

  Nonionic polymerization initiator

  Ionic polymerization initiator

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

  As the coating method, a known method 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 as in the case of the intermediate layer and the photosensitive layer. .

  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 5 to 100 mJ / cm ² . The power of the lamp is preferably 0.1 kW to 5 kW, 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 thickness of the protective layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

[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 zinc 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.

  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.

(Photosensitive layer)
Although there is no particular limitation, a so-called laminated photosensitive layer having a charge generation layer and a charge transport layer is preferable.

(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 generation material include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone 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, methacryloyl 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 photosensitive layer 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.

  As the charge transport material (CTM), it is preferable to use a charge transport material having an atomic weight ratio of N atoms of less than 4.5%. As the basic structure of the charge transport material, a triphenylamine derivative, a styryl compound, a benzidine compound, a butadiene compound, and the like can be used, and among them, a styryl compound is preferable.

  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 the electronic conductive agent as described in JP-A Nos. 50-137543 and 58-76483 are preferable.

  Hereinafter, the present invention will be described in detail with reference to typical embodiments of the present invention. However, the present invention is of course not limited thereto. In the following text, “part” means “part by mass”.

[Example of photoconductor preparation]
A photoreceptor was prepared as follows.

<Conductive support>
The surface of a cylindrical aluminum support (length: 360 mm) having a diameter of 100 mm was cut to prepare a conductive support having a surface roughness Rz = 1.5 (μm).

<Intermediate layer>
A dispersion having the following composition was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; using a lime mesh 5 μm filter manufactured by Nihon Pall) to prepare an intermediate layer coating solution.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part Titanium oxide SMT500SAS (manufactured by Teika) 3 parts Methanol 10 parts Dispersion was carried out for 10 hours in a batch manner using a sand mill as a disperser.

  It apply | coated by the dip coating method so that it might become a dry film thickness of 2.0 micrometers on the said support body using the said coating liquid.

<Charge generation layer>
Charge generation material: titanyl phthalocyanine pigment (titanyl phthalocyanine pigment having a maximum diffraction peak at a position of at least 27.3 ° by Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts polyvinyl butyral resin (# 6000-C: Electrochemical Industry) 10 parts) t-butyl acetate 700 parts 4-methoxy-4-methyl-2-pentanone 300 parts were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm.

<Charge transport layer>
Charge transport material (4,4′-dimethyl-4 ″-(β-phenylstyryl)
225 parts Binder: Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts Antioxidant (Irganox 1010: manufactured by BASF Japan) 6 parts THF (tetrahydrofuran) 1600 parts Toluene 400 parts Silicone oil (KF-54: Shin-Etsu) (Chemical Co., Ltd.) One part was mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer using a circular slide hopper coating machine and dried at 110 ° C. for 60 minutes to form a charge transport layer having a dry film thickness of 20 μm.

<Protective layer>
(Preparation of tin oxide particles)
100 parts by mass of tin oxide particles having a number average primary particle size of 30 nm, 30 parts by mass of “Exemplary Compound S-4” and 1000 parts by mass of methyl ethyl ketone as a surface treatment agent are placed in a wet sand mill (alumina beads having a diameter of 0.5 mm), and 30 ° C. Then, methyl ethyl ketone and alumina beads were separated by filtration and dried at 60 ° C. to prepare tin oxide particles 1 having reactive acryloyl groups.

Tin oxide particles 1 8 parts Curable monomer (Exemplary compound 1) 10 parts Polymerization initiator (Exemplary compound: Polymerization initiator 3-2) 1 part 1-Propyl alcohol 40 parts The above components are mixed and stirred, and sufficiently dissolved and dispersed. Then, a protective layer coating solution was prepared. A protective layer was applied using a circular slide hopper applicator on the photoreceptor on which the coating solution had been prepared up to the charge transport layer. After the coating, ultraviolet rays were irradiated for 1 minute using a metal halide lamp to obtain a protective layer having a dry film thickness of 2.0 μm.

<Cleaning device>
FIG. 2 is a diagram showing the configuration of the cleaning device 27.

  The cleaning device 27 removes residual toner on the surface of the photoconductor 21 and polishes the surface of the photoconductor 21, and includes a cleaning blade, a contact / separation mechanism that contacts or separates the cleaning blade from the photoconductor 21, and toner. And a scattering preventing member 279 for preventing scattering.

  The contact / separation mechanism includes a support member 273, a support shaft 274, and a first power device (not shown) that rotates the support member 273 about the support shaft 274.

  By rotating the support member 273 around the support shaft 274, the cleaning blade 271A can be brought into contact with or separated from the photoreceptor 21.

  The support member 273 supports the holding member 272 that holds the cleaning blades 271A and 271B as an automatic replacement mechanism that sets the cleaning blade 271B to a cleaning position where the cleaning blade 271B contacts the photosensitive member 21 instead of the cleaning blade 271A. The holding member 272 is driven and rotated by a second power unit (not shown) to set the cleaning blade 271A or the cleaning blade 271B to the cleaning position.

  The power device that rotates the holding member 272 and automatically exchanges the power is preferably based on the power when the repulsive force of the spring is charged and released, for example.

  A scattering prevention member 279 is provided for preventing toner scattering from the contact position of the cleaning blade 271A to the downstream side in the photosensitive member rotation direction. The tip of the scattering prevention member 279 contacts the photoconductor 21.

  The toner collection unit functions as a toner collection unit that collects toner removed from the surface of the photoreceptor 21 by the cleaning unit, and includes a cleaning brush 275, a flicker 276, a scraper 277, and a collection screw 78. The flicker 276 removes toner from the cleaning brush 275 by hitting the brush hair when the cleaning brush 275 rotates. The scraper 277 scrapes off the toner adhering to the surface of the flicker 276.

  The cleaning brush 275 as a polishing means for polishing the surface of the photoconductor 21 rotates in the direction indicated by the arrow W2 with respect to the photoconductor 21 rotating in the direction indicated by the arrow W1, and cleans the photoconductor 21. The surface of 21 is polished.

  Examples of the material for the cleaning brush 275 include polyester, nylon, rayon, polycarbonate, acrylic resin, and methacrylic resin. The cleaning brush 275 is made conductive by containing a conductive substance such as carbon.

<Polishing of photoreceptor surface>
When foreign matters such as discharge products adhere to the surface of the photoconductor, the image quality called image flow is deteriorated. For this reason, in the cleaning process, foreign matter is removed by a cleaning blade or a cleaning brush.

  The protective layer proposed in Patent Document 1 has characteristics that it has higher hardness than conventional protective layers and increases the durability of the photoreceptor. In such a photoconductor, not only the foreign matter on the surface of the photoconductor is removed, but also the performance of the photoconductor can be further utilized by making the polishing force for polishing the surface of the protective layer appropriate. As a result of an image formation test using the photoreceptor of Patent Document 1, it was found.

  When the polishing is insufficient, image quality deterioration called image flow occurs, such as a reduction in reproducibility of a halftone image and a reduction in image sharpness. In addition, when the polishing is excessive, the thickness of the protective layer is reduced early and the durability of the photoreceptor is lowered.

  As described above, it is necessary to control the polishing of the protective layer from the viewpoint of image quality and the life of the photoconductor. For this purpose, it is necessary to control the polishing performed in the image forming process. And in order to control polishing, it is necessary to grasp | ascertain the film thickness of a protective layer.

  Although there are various methods for measuring the thickness of the protective layer, the exposure potential method using the exposure potential is convenient for use in the electrophotographic process. In the exposure potential method, the photosensitive member is charged to a predetermined potential and then exposed to a predetermined amount of light, for example, exposed to the maximum amount of light, and the film thickness of the protective layer of the photosensitive member is determined from the surface potential of the photosensitive member after the exposure. Is a method of measuring.

  FIG. 3 shows an example of the relationship between the exposure potential of a photoreceptor having a protective layer and the thickness of the protective layer. In FIG. 3, the vertical axis represents the potential (exposure potential) when a charged photoconductor is exposed with a predetermined amount of light, such as the maximum exposure amount, and the horizontal axis represents the thickness of the protective layer. As shown in the figure, the exposure potential and the film thickness are in a proportional relationship. The exposure potential is measured by the potential sensor VS shown in FIG. 1, that is, the potential sensor VS that detects the surface potential of the photosensitive member 21 after exposure. From the relationship shown in FIG. 3, it is possible to detect the thickness of the protective layer by measuring the exposure potential with the potential sensor VS. Then, by detecting the film thickness of the protective layer by the exposure potential method, it becomes possible to evaluate the polishing effect in the polishing of the photoreceptor. That is, the polishing power of the polishing means can be grasped by measuring the film thickness of the protective layer in the initial stage and measuring the film thickness of the protective layer when the photoconductor is rotated a predetermined number of times while forming the image while polishing the surface of the photoconductor. Is done.

  The wear index α is used as an index representing such polishing power. The wear index α is a wear amount (μm / 100,000 rot) per unit rotation (for example, 100,000 times) of the photoreceptor.

  FIG. 4 shows the relationship between the image quality and the photoreceptor and the wear index α. In FIG. 4, the level L1 of the wear index α is the upper limit for ensuring the expected durability of the photoreceptor, the level L2 is the lower limit for preventing image flow under high temperature and high humidity, and the level L3 is under normal temperature and normal humidity. Is a lower limit value for preventing image flow.

  As shown in FIG. 4, a high-quality image is formed by maintaining the wear index α in an appropriate range between the level L1 and the level L2 or between the level L1 and the level L3, and sufficient photoreceptor durability is achieved. It can be secured. A curve L4 in FIG. 4 shows the relationship between the speed difference between the cleaning brush and the photoreceptor and the wear index α.

The protective layer on the surface of the photosensitive member is polished by rubbing the surface of the photosensitive member with a cleaning brush. In the polishing with the cleaning brush, the wear index α is adjusted by the polishing force adjusting means listed in the following a1 to a4.
a1. Speed difference adjusting means The speed difference between the photoconductor and the cleaning brush is a difference between the peripheral speed of the surface of the photoconductor and the peripheral speed of the surface of the cleaning brush, and the wear index α increases as the speed difference increases. When the peripheral surface of the photoconductor and the peripheral surface of the cleaning brush move in opposite directions, the speed difference is large, and when moving in the same direction, the speed difference is small.
a2. Forming toner amount adjusting means (band width adjusting means)
The toner contains an abrasive that polishes the photoreceptor as described in the section of the developer. Therefore, as the amount of toner held by the cleaning brush increases, the amount of abrasive held by the cleaning brush increases and the wear index α increases. The amount of toner held on the cleaning brush is adjusted by adjusting the amount of toner that forms a toner image for photoconductor polishing formed on the photoconductor as follows. For example, it is adjusted by adjusting the width of the toner band for photoconductor polishing.

  FIG. 5 shows a toner band formed on the photoconductor 21 for photoconductor polishing. As shown in the figure, the toner band TB is formed outside the image area between the plurality of toner images G. The toner band TB is formed on the photoreceptor 21 by the charging device 22, the exposure device 23, and the developing device 24 that constitute the toner band forming unit. That is, the toner band TB is formed on the photosensitive member 21 by charging by the charging device 22, strip exposure by the exposure device 23, and development by the developing device 24. The toner image G is transferred to the recording material, and in the image area, the untransferred toner is brought into the cleaning device, but the toner band TB formed outside the image area is brought into the cleaning device 27 without being transferred, It is collected by the cleaning brush 275. For this purpose, a transfer voltage is applied in the image area where the toner image G is formed, and a voltage opposite to the transfer voltage is applied outside the image area where the toner band TB is formed.

The amount of toner collected by the cleaning brush 275 changes and the amount of toner held by the cleaning brush 275 changes by adjusting the exposure width when the exposure device 23 as the band width adjusting unit performs the strip exposure. To do.
a3. Toner Movement Amount Adjustment Unit FIG. 6 shows a toner movement amount adjustment unit that adjusts the toner movement amount by adjusting the voltage.

  A variable voltage is applied between the photosensitive member 21 and the cleaning brush 275 by a power source E1 as a toner movement amount adjusting means. When negatively charged toner is used, a positive voltage is applied to the cleaning brush 275, and the amount of toner transferred from the photoreceptor 21 to the cleaning brush 275 is changed by changing the applied voltage value.

The voltage between the photosensitive member 21 and the cleaning brush 275 is normally set so that the transfer residual toner on the photosensitive member 21 passes through the cleaning brush 275 and reaches the position of the cleaning blade and is scraped off and removed by the cleaning blade. However, the amount of toner collected by the cleaning brush 275 can be adjusted by adjusting the voltage between the photoconductor 21 and the cleaning brush 275. By increasing the voltage and increasing the amount of toner transferred to the cleaning brush 275, the amount of toner collected by the cleaning brush 275 increases, and the polishing force of the cleaning brush 275 increases.
a4. Toner removal amount adjusting means The toner held on the cleaning brush 275 is removed from the cleaning brush 275 by a tapping member 276 as a brush cleaning means. In this manner, the amount of toner held on the cleaning brush 275 is maintained at a constant level by balancing the amount recovered from the photoreceptor 21 and the amount removed by the tapping member 276. The amount of toner held by the cleaning brush 275 can be changed by changing the amount of toner removed by the tapping member 276.

  FIG. 6 also shows means for controlling the amount of toner held on the cleaning brush by controlling the cleaning of the cleaning brush.

  A voltage is applied between the cleaning brush 275 and the hitting member 276 by the power source E2 as toner removal amount adjusting means, and the amount of toner held on the cleaning brush 275 changes by changing the applied voltage. The amount of toner held by the cleaning brush 275 can also be controlled by controlling the speed difference between the cleaning brush 275 and the hitting member 276.

  The relationship between the adjustment values of the polishing force adjusting means a1 to a4 and the wear index α can be examined in advance, for example, as shown by a curve L4 in FIG. Therefore, in the image forming process, it is possible to determine an adjustment value of the polishing force adjusting means for setting the wear index α to an appropriate value. In this way, it becomes possible to adjust the polishing power of the polishing means comprising the cleaning brush to a desired level. The a1 to a4 polishing force adjusting means can be used in any one or a combination thereof.

On the other hand, the image quality is affected by the following factors related to the wear index α.
b1. Environment Environmental temperature or humidity has various effects on image quality. For example, since the image flow is likely to occur in an environment with high humidity, it is necessary to increase the wear index α. Further, at high humidity, the pressing force of the cleaning brush 275 decreases, and as a result, the speed difference between the photosensitive member 21 and the cleaning brush 275 needs to be increased.
b2. Paper type The photoreceptor contacts the transfer material at the transfer position, and the toner image is transferred to the recording material. The photosensitive member 21 is worn due to contact with the transfer material during transfer. As can be seen from this, the wear on the photoconductor 21 changes depending on the type of transfer material, and the wear index α changes.
b3. Printing Rate The higher the printing rate of the image to be formed, the greater the amount of residual toner, that is, the amount of toner brought into the cleaning device 27, and the wear index α increases.
b4. Photoreceptor History The protective layer becomes worn and thin as the photoreceptor history increases. Therefore, it is necessary to lower the wear index α as the history of the photoreceptor increases.
b5. Cleaning Brush History As the history of the cleaning brush 275 increases, its polishing power decreases. That is, as shown in FIG. 7, the pressure of the cleaning brush 275 decreases with an increase in the number of printed sheets. In addition, the curve L5 in FIG. 7 shows the change when the initial value of the brush pressure is set high, and the curve L6 shows the change when the initial value of the brush pressure is set low. Therefore, in order to maintain the desired polishing force, it is necessary to adjust the polishing force adjusting means such as increasing the speed difference in response to an increase in the history of the cleaning brush 275.

  In the photoconductor of the present invention, the abrasion index α is controlled within the appropriate range by controlling the polishing force adjusting means in accordance with each change of the factors b1 to b5, thereby maintaining the wear index α within an appropriate range. It is possible to stably form the image.

  Furthermore, by controlling the polishing force adjusting means a1 to a4 based on a combination of any two or more of the factors b1 to b5, the wear index α is reliably maintained within an appropriate range, and a high quality image is more stable. Can be formed.

  In particular, by controlling the polishing force adjusting means a1 to a4 based on the combination of the factors b1, b2 and b3, the wear index α is reliably maintained within an appropriate range, and a high-quality image is formed very stably. In addition, the life of the photoconductor can be extended.

  FIG. 8 is a block diagram of a control system for inputting the information on the factors b1 to b4 and controlling the polishing force adjusting means a1 to a4.

  CR is a control means for controlling the polishing force of the cleaning brush, SE1 is a temperature sensor for detecting the temperature in the image forming apparatus, and SE2 is a humidity sensor for detecting the humidity in the image forming apparatus. The temperature sensor SE1 and the humidity sensor SE2 constitute an environment sensor that detects the environment in the image forming apparatus. 0P is an image forming condition, in particular, an operation unit as paper type information generating means for generating information on the paper type of the recording material P to be used, and IP is information on the printing rate from the image data of the image to be formed. An image processing unit serving as a printing rate information generating unit, ED is a photosensitive member moving distance meter as a photosensitive member history information generating unit generating information on a photosensitive member moving distance, and 23 is a photosensitive member formed on the photosensitive member. An exposure device as a band width adjusting means for adjusting the width of the toner band for body polishing, BM is a brush motor as a speed difference adjusting means for rotationally driving the cleaning brush, and E1 is between the photoconductor and the cleaning brush as described above. A power source as a toner movement amount adjusting means for applying a voltage for moving the toner to the cleaning brush, E2, as described above, moves the toner to the hitting member between the cleaning brush and the hitting member. A power supply as a toner removing amount adjusting means for applying a voltage.

  The photoconductor moving distance meter ED measures the moving distance of the photoconductor by accumulating pulses from an encoder provided on the photoconductor, and the photoconductor 21 after the photoconductor 21 is mounted on the image forming apparatus. Accumulate travel distance. Since the cleaning brush operates simultaneously with the photosensitive member, the moving distance of the surface of the cleaning brush, that is, the history information of the cleaning brush can be obtained from the measurement of the moving distance of the photosensitive member. As described above, the photoconductor moving distance meter ED constitutes polishing history information generating means for generating cleaning brush history information.

  The control means CR is based on information from at least one of the temperature sensor SE1, the humidity sensor SE2, the operation unit OP, the image processing unit IP, and the photoreceptor movement distance meter ED, and the brush motor BM, the power sources E1, E2, and the like. At least one or more of the exposure apparatus 23 is controlled to make the wear index α appropriate for various factors.

[Embodiment 2]
In the present embodiment, the polishing force of the cleaning brush is detected, and the polishing force is controlled to an appropriate value based on the detected polishing force. The configurations of the image forming apparatus and the cleaning apparatus are shown in FIGS.

  FIG. 9 is a block diagram of a control system for controlling the polishing force adjusting means.

  In FIG. 9, VS is a potential sensor that detects the exposure potential, and detects the potential of the photosensitive member 21 between the exposure position of the exposure device 23 and the developing device 24, as shown in FIG.

  The control means CR controls the charging device 22 and the exposure device 23 to charge the photoconductor 21 and form an exposure potential on the photoconductor 21 by performing exposure with a predetermined amount of light. The potential sensor VS detects the formed exposure potential. The control means CR calculates the wear index α based on the information from the potential sensor VS and the information on the photoconductor moving distance meter ED. Then, the control means CR controls the polishing power by controlling one or more of the exposure device 23, the brush motor BM, and the power sources E1 and E2 so that the calculated wear index α becomes an appropriate value.

  The control means CR determines the optimum wear index α corresponding to the change of the factors b1 to b4, and selects and selects the polishing force adjusting means a1 to a4 so as to achieve the polishing power that realizes the determined wear index α. And controlling the polishing force adjusting means.

  For example, as shown in FIG. 4, the lower limit of the wear index α at normal temperature and normal humidity is different from the lower limit of the wear index α at high temperature and high humidity. Further, when the history of the photosensitive member becomes long, the surface layer is deteriorated by ozone or the like and the image flow is likely to occur, so it is necessary to increase the wear index α. The control means CR sets an optimum wear index α for such factors.

[Embodiment 3]
FIG. 11 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. This color image forming apparatus includes an image reading unit B, an image forming unit C, and a recording material conveying unit D. The image forming unit C includes four image forming units 10Y, 10M, 10C, and 10K.

  The image forming unit 10Y that forms a yellow image includes a drum-shaped photoreceptor 1Y, a charging device 2Y, an exposure device 3Y, a developing device 4Y, a primary transfer roller 5Y as a transfer device, and a cleaning device 6Y. The image forming unit 10M that forms a magenta image includes a drum-shaped photoreceptor 1M, a charging device 2M, an exposure device 3M, a developing device 4M, a primary transfer roller 5M as a transfer unit, and a cleaning device 6M. The image forming unit 10C that forms a cyan image includes a drum-shaped photoreceptor 1C, a charging device 2C, an exposure device 3C, a developing device 4C, a primary transfer roller 5C as a transfer unit, and a cleaning device 6C. The image forming unit 10K that forms a black image includes a drum-shaped photoreceptor 1K, a charging device 2K, an exposure device 3K, a developing device 4K, a primary transfer roller 5K as a transfer unit, and a cleaning device 6K.

  The image forming units 10Y, 10M, 10C, and 10K have the same configuration except that the toner images formed on the photoreceptors 1Y, 1M, 1C, and 1K have different colors. The image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y includes a charging device 2Y, an exposure device 3Y, a developing device 4Y, and a cleaning device 6Y disposed around a photoconductor 1Y that is an image forming body, and yellow (Y) toner on the photoconductor 1Y. Form an image. In the present embodiment, the image forming unit 10Y is configured as a unit in which at least the photoreceptor 1Y, the charging device 2Y, the developing device 4Y, and the cleaning device 6Y are integrated.

  The charging device 2Y is means for applying a uniform potential to the photoreceptor 1Y. In this embodiment, a corona discharge type charger is used for the photoreceptor 1Y.

  The exposure device 3Y is a means for forming an electrostatic latent image corresponding to a yellow image by performing exposure based on an image signal (yellow) on the photoreceptor 1Y to which a uniform potential is applied by the charging device 2Y. As the exposure device 3Y, an exposure apparatus 3Y composed of LEDs having light emitting elements arranged in an array in the axial direction of the photoreceptor 1Y and an imaging element (trade name; Selfoc lens), or a laser optical system Etc. are used.

  The developing device 4Y develops the electrostatic latent image with a two-component developer including toner and carrier.

  A transfer voltage is applied to the primary transfer roller 5Y, and the toner image on the photoreceptor 1Y is transferred to the intermediate transfer member 31.

  The cleaning device 6Y scrapes and cleans the transfer residual toner on the photoreceptor 1Y with a cleaning blade.

  The intermediate transfer body unit 30 includes a plurality of rollers 32 to 35 and a semiconductive endless belt-shaped intermediate transfer body 31 that is wound around the plurality of rollers 32 to 35 and is rotatably supported.

  The toner images of the respective colors formed by the image forming units 10Y, 10M, 10C, and 10K are sequentially transferred onto the rotating intermediate transfer member 31 by primary transfer rollers 5Y, 5M, 5C, and 5K as transfer means. A synthesized color image is formed. The recording material P stored in the paper feed tray 41 is fed by the paper feed unit 42 and is conveyed to the secondary transfer roller 5 </ b> A through a plurality of conveyance rollers 43 and registration rollers 44. The color image is collectively transferred onto the recording material P by the secondary transfer roller 5A. The recording material P to which the color image has been transferred is subjected to fixing processing by the fixing device 50 and placed on a paper discharge tray 64 outside the apparatus.

  On the other hand, after the color image is transferred to the recording material P by the secondary transfer roller 5A as the secondary transfer means, the intermediate transfer body 31 from which the recording material P is separated by curvature is cleaned by the cleaning device 6A.

  During the image forming process, the primary transfer roller 5K is always in contact with the photoreceptor 1K. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A contacts the endless belt-shaped intermediate transfer body 70 only when the recording material P passes through the secondary transfer roller 5A and secondary transfer is performed.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An intermediate transfer body unit 30 is arranged on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The intermediate transfer body unit 30 includes an endless belt-shaped intermediate transfer body 31 that can be rotated by winding rollers 32 to 35, primary transfer rollers 5Y, 5M, 5C, and 5K, and a cleaning device 6A.

  The conveyance path 40 for supplying the recording material P to the secondary transfer position formed by the secondary transfer roller 5A has three sheet feeding trays 41 arranged vertically, and a sheet feeding unit for feeding the recording material from the sheet feeding tray 41. 42, a plurality of conveying rollers 43 that convey the recording material P sent out by the paper feeding unit 42, and a registration roller 44 that conveys the recording material P to the secondary transfer position. Reference numeral 46 denotes a manual sheet feeder.

  The paper discharge conveyance unit that conveys and discharges the recording material P that has been subjected to fixing processing includes a lower conveyance path 61 that conveys the recording material P discharged from the fixing device 50 downward, and a refeed unit that conveys the recording material P to the secondary transfer position. 62, a reversing unit 63 that receives the recording material from the lower conveyance path 61 and reverses the recording material, and conveys the recording material to the refeed unit 62, and a paper discharge tray 64.

  The recording material P discharged from the fixing device 50 is discharged to the discharge tray 64 as it is, and after being transported to the lower transport path 61, the transport direction is reversed and transported upward in the lower transport path 61 to be discharged. There is a paper discharge mode for conveying to the tray 64.

  In double-sided image formation, the recording material P on which an image has been formed on the first surface and passed through the fixing device 50 is transported downward in the lower transport path 61 and turned upside down by the reversing unit 63, and then the refeeding unit 62 The paper is transported and fed again to the secondary transfer position.

  An image is formed on the second surface, and the recording material P discharged from the fixing device 50 is discharged to the discharge tray 64 as it is.

  In the image forming apparatus of FIG. 11, each of the photoreceptors 1Y, 1M, 1C, and 1K has the above-described photoreceptor, that is, tin oxide particles having a reactive acryloyl group or methacryloyl group, a reactive methacryloyl group, and An electrophotographic photosensitive member having a protective layer made of a composition obtained by reacting a curable monomer having a functional group density of a reactive methacryloyl group greater than 0.005.

  A cleaning device 6Y for cleaning the photoreceptor 1Y, a cleaning device 6M for cleaning the photoreceptor 1M, a cleaning device 6C for cleaning the photoreceptor 1C, and a cleaning device 6K for cleaning the photoreceptor 1K are shown in FIG. A cleaning brush and a cleaning means for removing toner from the cleaning brush are provided.

  The photoreceptors 1Y, 1M, 1C, and 1K are polished by the cleaning brushes of these cleaning devices 6Y, 6M, 6C, and 6K.

  In the color image forming apparatus shown in FIG. 11, since the toner images on the photoreceptors 1Y, 1M, 1C, and 1K are transferred to the intermediate transfer body 31, the photoreceptors 1Y, 1M, 1C, and 1K are in contact with the recording material P. do not do. Therefore, the polishing of the photoreceptors 1Y, 1M, 1C, and 1K is not affected by the paper type.

  Therefore, in the present embodiment, in the control of the polishing force adjusting means, it is preferable that the control means adjusts the polishing power based on the combination factor of the environment and the printing rate. Image formation is possible, and the life of the photoreceptor is extended.

<Example 1>
(1) Example An image forming apparatus equipped with the photoconductor of the present invention prepared according to the photoconductor preparation example shown in FIG. 1 was used, and the following was used as the cleaning device 27.
・ Cleaning blade Method: Counter method Material: Urethane rubber Rubber hardness: 65 ° (JISA)
Rebound resilience: 50%
Length: 363.5mm
Thickness: 2mm
Free length: 9mm
Pressing method: Weight method Contact load: 17 N / m
Contact angle (angle as rigid body): 20 °
-Cleaning brush Material: Conductive polyester Wire diameter: 10d
Density: 40000 pieces / 25.4mm
Brush roller shaft diameter: φ12mm
Outer diameter: φ19mm
Hair length: 3.8mm
Biting into the photoreceptor: 1.0 mm
Rotation direction: Rotation direction in which the peripheral surface of the brush roller moves in the same direction as the peripheral surface of the photosensitive member.
Diameter: φ10mm
Brush speed ratio: 0.5
The amount of brush biting into the hitting member: 0.85mm
Tapping member is grounded and scraper Material: SUS
Thickness: 0.05mm
・ Abrasive Calcium titanate Content in toner: 0.5% by mass
The polishing power was set to the following three levels.
○ High polishing power:
Speed difference = 400mm / s
Toner band width 10mm
α = 0.4
Toner band formation for feeding toner to the cleaning device: Band width 10 mm
○ During polishing power:
Speed difference = 250mm / s
Toner band width 0mm
α = 0.2
No toner band for sending toner to the cleaning device ○ Low polishing power:
Speed difference = 50mm / s
Toner band width 0mm
α = 0.1
No toner band for feeding toner to the cleaning device was formed. As shown in Table 1, the polishing power was optimally set for the combination factors of environment, paper type and printing rate.

As shown in Table 1, an image having a good image quality was obtained with respect to a change in environment, a change in paper type, and a change in printing rate, and a photoreceptor durability of 1000 k or more was obtained. In Table 1, o indicates extremely good image quality, and Δ indicates good image quality.
<Comparative example>
In order to ensure the life of the photoconductor, a photoconductor described in JP-A-8-262275, that is, a photoconductor whose surface layer contains silica fine particles to improve durability is used. The image was formed with a small polishing power in 1.

  The results are shown in Table 2.

  As shown in Table 2, image flow occurred at high temperature, high humidity, coated paper, and high printing rate.

1C, 1M, 1K, 1Y, 21 Photoconductor 22, 2C, 2M, 2K, 2Y Charging device 23, 3C, 3M, 3K, 3Y Exposure device 24, 4C, 4M, 4K, 4Y Developing device 25 Transfer device 5C, 5M 5K, 5Y Primary transfer roller 27, 6C, 6M, 6K, 6Y Cleaning device 275 Cleaning brush CR control means SE1 Temperature sensor SE2 Humidity sensor IP Image processing unit ED Photoreceptor moving distance meter

Claims (7)

Tin oxide particles having a reactive acryloyl group or a methacryloyl group, a reactive methacryloyl group, and the formula {functional group density of the reactive methacryloyl group = (the number of reactive methacryloyl groups) / (of the curable monomer) (Molecular weight)}, a photoconductor comprising an organic electrophotographic photoconductor having a protective layer comprising a composition obtained by reacting a reactive methacryloyl group having a functional group density of greater than 0.005. When,
Toner image forming means for forming a toner image on the photoreceptor;
A transfer device for transferring the toner image on the photosensitive member to a transfer member;
An image forming apparatus comprising: a cleaning device that cleans the photoconductor after transfer, and a cleaning device that includes a polishing unit that polishes the surface of the photoconductor.
An image forming apparatus comprising: a polishing force adjusting unit that adjusts a polishing force of the polishing unit; and a control unit that controls the polishing force adjusting unit. An environmental sensor that detects temperature and humidity;
Paper type information generating means for generating information on the type of transfer member;
Printing rate information generating means for generating printing rate information of an image to be formed;
Photoconductor history information generating means for generating information on the history of the photoconductor;
Having at least one of polishing history information generating means for generating history information of the polishing means,
The control means includes at least one of the environmental sensor, the paper type information generation means, the printing rate information generation means, the photoconductor history information generation means, and the polishing history information generation means. The image forming apparatus according to claim 1, wherein the polishing force adjusting unit is controlled based on information. The polishing force adjusting means includes
A speed difference adjusting means for adjusting a difference between a surface speed of the photoconductor and a surface speed of the polishing means;
Forming toner amount adjusting means for adjusting the amount of toner for forming a toner image for photoconductor polishing formed on the photoconductor;
A toner movement amount adjusting unit that adjusts a voltage between the photoconductor and the polishing unit to adjust an amount of toner that moves from the photoconductor to the polishing unit;
The image forming apparatus according to claim 1, further comprising at least one of a toner removal amount adjusting unit that adjusts an amount of toner removed from the polishing unit. The transfer device transfers a toner image to the transfer body made of a recording material,
The control means controls the polishing force adjusting means based on a combination of information from the environmental sensor, information from the paper type information generating means, and information from the printing rate information generating means. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus. The transfer body is an intermediate transfer body,
The said control means controls the said grinding | polishing force adjustment means based on the combination of the information from the said environmental sensor, and the information from the said printing rate information generation means, The said 2 or 3 characterized by the above-mentioned. Image forming apparatus. Having a potential sensor that detects an exposure potential that is a potential when the charged photoreceptor is exposed to a predetermined amount of light;
The image forming apparatus according to claim 1, wherein the control unit controls the polishing force adjusting unit based on information from the potential sensor. An environmental sensor that detects temperature and humidity;
Photoconductor history information generating means for generating information on the history of the photoconductor;
Having at least one of polishing history information generating means for generating history information of the polishing means,
The control means controls the polishing force adjusting means based on information from at least one of the environmental sensor, the photoreceptor history information generating means, and the polishing history information generating means. The image forming apparatus according to claim 6.

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