JP2011095648A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus of a cleaning blade-less type which is superior so that a high-quality print image is continuously obtained in a state of being free of image memory even when printing a number of sheets. <P>SOLUTION: The image forming apparatus includes a charging means, an exposure means, and a transfer means, and has a conductive contact member which comes in contact with a photoreceptor on a position of the downstream side from the transfer means and of the upstream side from the charging means and which has such a function as to recover the transfer residual toner of the photoreceptor temporarily and deliver the recovered toner onto the photoreceptor, wherein a developing means has such a function as to recover the delivered toner onto the photoreceptor simultaneously with the development. In the apparatus, the photoreceptor has a protective layer on the uppermost surface, and the protective layer contains a component obtained by reacting a metal oxide particle surface-treated with a surface-treating agent having a reactive organic group, with a curable compound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus employing an electrophotographic method.

  In recent years, there has been a demand for a small and highly reliable image forming apparatus. In particular, there is an increasing demand for an image forming apparatus that is compact and easy to maintain while maintaining high image quality. For this purpose, cleaningless image formation in which the toner remaining on the photoconductor after transfer is not scraped off, is left on the photoconductor, passes through the charging device and the exposure device, and is collected and reused by the developing device. A device has been proposed.

  However, in the above-described cleaningless image forming apparatus, since charging / exposure is performed in a state where the residual toner is placed on the photosensitive member, fog due to toner spilling appears on the print at random, which is a problem.

  Therefore, the toner remaining on the photoconductor after the transfer is temporarily taken into a toner holding means such as a rotating brush at the time of image formation, temporarily held, and the toner is discharged onto the photoconductor at times other than the time of image formation to develop the developing device. Has been proposed (see, for example, Patent Document 1).

  However, in the cleaningless image forming apparatus as described above, it is difficult to efficiently take in the toner remaining on the photoreceptor after the transfer to the brush, and the toner once held on the brush is efficiently used at times other than during image formation. It was also difficult to spit out on the photoreceptor. For this reason, the brush is contaminated with toner, and the toner adheres to the brush and the toner spills due to contact with the photoreceptor. When this toner spilled on the paper, it appeared as a fog. These problems were particularly remarkable at the time of durability.

  As described above, in the cleaning bladeless image forming apparatus in which the residual toner is temporarily taken in and held by the brush and then discharged to the photosensitive member and collected by the developing device, taking in and discharging by the brush are unstable, In the current situation, high quality images cannot be obtained stably.

  Further, a potential adjusting means for adjusting the surface potential of the photoconductor after transfer is disposed at a position downstream of the transfer means in the rotation direction of the photoconductor, and at a position between the potential adjusting means and the charging means. A toner disturbance rotator that rotates in contact with the surface of the photoconductor while a bias voltage is applied is provided, and the toner disturbance rotator passes through the image forming area of the photoconductor after transfer. While applying a bias voltage capable of forming an electric field that causes the residual toner to adhere to the toner disturbance rotator, the residual toner adhering to the toner disturbance rotator passes through the non-image forming area of the photoconductor. There has been proposed a cleanerless type image forming apparatus in which a bias voltage capable of forming an electric field attached to the image is applied (see, for example, Patent Document 2).

JP 2003-167476 A JP 9-325607 A

  However, when a large number of sheets are printed using the image forming apparatus disclosed above, there is a problem that an image memory is generated in the printed image, and a high-quality printed image cannot be obtained continuously.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent cleaning bladeless image forming apparatus that does not have an image memory even when a large number of sheets are printed and can continuously obtain high quality printed images.

  The object of the present invention is achieved by adopting the following configuration.

1. A charging unit for applying a charging potential on the photosensitive member, an exposure unit for exposing the photosensitive member to which the charging potential has been applied to form an electrostatic latent image, and a development for developing the electrostatic latent image into a toner image And a transfer means for transferring the toner image to the transfer body, contacting the photoreceptor at a position downstream from the transfer means and upstream from the charging means, and temporarily collecting the residual toner on the photoreceptor. In an image forming apparatus having a conductive contact member having a function of discharging the toner that has been discharged onto the photosensitive member, and having a function of collecting the toner discharged on the photosensitive member simultaneously with the development.
The photoreceptor has a protective layer on the outermost surface;
An image forming apparatus, wherein the protective layer contains a component obtained by reacting a metal oxide particle surface-treated with a surface treating agent having a reactive organic group and a curable compound.

  2. 2. The image forming apparatus according to 1 above, wherein the protective layer does not contain a compound having a charge transporting structure.

  3. 3. The image forming apparatus according to item 1 or 2, wherein the curable compound is a compound having either an acryloyl group or a methacryloyl group.

  4). 4. The image forming apparatus as described in any one of 1 to 3, wherein the surface treatment agent is a surface treatment agent having either an acryloyl group or a methacryloyl group.

  The cleaning bladeless image forming apparatus of the present invention has an excellent effect that even if a large number of sheets are printed, there is no image memory, and high quality printing can be continuously obtained.

1 is a schematic diagram illustrating an example of a cleaning bladeless image forming apparatus of the present invention. FIG. 6 is a schematic diagram illustrating the behavior of toner while an image forming area portion of a photoconductor passes and the behavior of toner while a non-image forming area portion of the photoconductor passes.

  When a large number of sheets are printed using a cleaning bladeless image forming apparatus, an image memory is generated with the combination of the disclosed photoconductor and memory removal member (potential adjusting means + toner disturbance rotating body), and the quality is continuously increased. There was a problem that the prints could not be obtained.

  The inventors of the present invention have inferred that when the disclosed photoreceptor is loaded into a cleaning bladeless image forming apparatus and a large number of sheets are printed, the previous image remains as a potential memory on the photoreceptor.

  It is presumed that the potential memory is generated because the toner disturbance effect by the dust removing member provided at a position downstream of the transfer unit and upstream of the charging unit is small.

  The inventors of the present invention have studied a cleaning bladeless image forming apparatus that does not have an image memory even when a large number of sheets are printed and can continuously obtain high-quality prints.

  As a result of various studies, when using a photoreceptor provided with a protective layer on the outermost surface containing a component obtained by reacting a metal oxide particle surface-treated with a surface treatment agent having a reactive organic group and a curable compound The present inventors have found that even when a large number of sheets are printed by an image forming apparatus without a cleaning blade, there is no image memory and high quality prints can be continuously obtained.

  The image memory can be eliminated because the photoconductor provided with the protective layer on the outermost surface has good transferability and little residual toner (hereinafter also referred to as transfer residual toner). It is assumed that the amount of toner collected can be reduced. As a result, it is presumed that the potential memory in the place corresponding to the previous image portion on the photosensitive member can be reduced.

  Further, the toner remaining on the surface of the photoconductor is disturbed by the conductive contact member (hereinafter, also referred to as a toner disturbing effect), so that the potential memory at the location corresponding to the remaining toner portion disappears, and a large number of sheets are printed. Even so, it is presumed that images without an image memory can be obtained continuously.

  Furthermore, the image memory can be further improved by using a compound having a charge transporting structure or a photoreceptor provided with a protective layer not containing the charge transporting structure on the outermost surface of the photoreceptor. The reason for this is not clear, but the carrier does not move to the surface of the protective layer, and the carrier stays at the interface between the protective layer and the charge transport layer, so the binding force of the toner is weakened, and the conductive contact member scrapes off. I think this is because my nature has improved.

  Further, it is preferable to use a compound having a methacryloyl group as the curable compound and the surface treatment agent because transferability and toner releasability are improved, and even when a large number of sheets are printed, image memory is prevented from being generated.

  Also, the cleaning bladeless image forming apparatus of the present invention collects the transfer residual toner and can be reused. Therefore, the toner is not discarded and is friendly to the environment.

  First, the cleaning bladeless image forming apparatus of the present invention will be described.

<Image forming apparatus>
FIG. 1 is a schematic view showing an example of an image forming apparatus of the present invention without a cleaning blade.

  In FIG. 1, reference numeral 1 denotes a photoreceptor that rotates in the direction of an arrow. Around the photoreceptor 1, a charging device 2, an image exposure device 3, a developing device 4, a transfer device 5, and a conductive contact member (hereinafter also simply referred to as a contact member) 8 are arranged in this order. Has been.

  In the image forming apparatus of the present invention, the charging device 2 includes a charging roll 20 that rotates in contact with the surface of the photosensitive drum 1, and a charging power source 21 that applies a predetermined charging voltage to the charging roll 20. The surface of the photosensitive drum 1 is charged to a constant potential. The image exposure apparatus 3 is, for example, a laser type exposure apparatus, and forms an electrostatic latent image by performing exposure according to image information on the uniformly charged surface of the photosensitive drum.

  The charging device 2 may be a corotron or scorotron charger.

  The developing device 4 includes an apparatus main body including a developing roll 40 that rotates to face a photosensitive drum, and a developing bias power source 41 that applies a predetermined developing bias to the developing roll 40. The image is visualized with toner supplied by the developing roll 40 to form a toner image, and at the same time, residual toner adhering to the non-image area is electrostatically attracted to the developing roll 40 and collected.

  The transfer device 5 includes, for example, a transfer corotron 50 and a transfer power supply 51 that applies a predetermined transfer voltage to the corotron 50, and a recording medium (transfer paper) 6 to which a toner image is supplied at a predetermined timing. Transfer electrostatically. Specifically, a peeling device is provided on the downstream side in the rotation direction of the photosensitive member 1 with respect to the transfer device 5, and the recording medium 6 after transfer is peeled off electrostatically or mechanically from the surface of the photosensitive drum 1. Yes.

  The contact member 8 is positioned between the transfer device 5 and the charging device 2 and rotates while contacting the surface of the photosensitive drum 1 while a bias voltage is applied. As the contact member 8, the rotating brush 80 is used in the image forming apparatus of FIG. 1, but a rotating elastic roll or the like may be used. Further, the contact member 8 has a bias voltage source 81a or 81b for disturbing bias voltage that varies between the time when the image forming area portion of the photoreceptor after the transfer passes and the time when the non-image forming area portion of the photoreceptor passes. Are switched and applied by a changeover switch 82. That is, while the image forming area portion of the photoconductor after transfer passes, a bias voltage capable of forming an electric field is formed so that residual toner remaining on the photoconductor drum 1 after transfer adheres to the contact member 8 side. On the other hand, while the non-image forming area portion of the photoconductor passes, a bias voltage is applied so as to form an electric field so that the residual toner adhering to the contact member 8 adheres to the photoconductor drum 1 side. It has become. The voltage applied to the contact member 8 is a DC voltage or a superimposed voltage obtained by superimposing DC and AC.

  In the image forming apparatus of the present invention, while the image forming area of the photoreceptor after transfer passes, the polarity is opposite to the polarity of the toner (during development), and the potential on the entire surface of the photoreceptor drum 1 The voltage is applied to a value larger than the absolute value of (the potentials of the exposed part and the non-exposed part of the image forming region part and all the potentials of the non-image forming region part).

  The bias voltage applied to the contact member 8 is not limited to this example. Residual toner adheres electrostatically to the contact member 8 when passing through the image forming area, and the residual toner flows when passing through the non-image forming area. Any electric field that electrostatically adheres to the photosensitive drum 1 from the contact member 8 may be used. Therefore, when such an electric field can be formed, a bias voltage having the same polarity and having an appropriate voltage value may be used.

《Conductive contact member》
When a rotating brush is used as the conductive contact member 8, the rotating brush 80 is formed by forming a brushed semiconductive fiber layer in a cylindrical shape on a conductive rotating shaft. As the semiconductive fiber layer, for example, a material in which a conductive material such as carbon black is dispersed in acrylic, rayon, polypropylene, nylon, or the like, or a metal compound having a multi-layer structure is made into a fiber shape, and the fiber A fiber material in which the volume resistance is set to 10 ⁵ to 10 ¹⁰ Ω · cm and the thickness of the fiber is set to 2.5 to 17 denier, and the length of the hair is raised to 2 to 10 mm. Is used.

When a rotating elastic roll is used as the contact member 8, the rotating elastic roll has a semiconductive elastic body layer formed on a conductive rotating shaft. Examples of the semiconductive elastic layer include an ion conductive material such as carbon black, metal oxide such as tin, perchlorate, and quaternary ammonium salt in an elastic member such as urethane foam and EPDM. In which the volume resistance value is made 10 ⁵ to 10 ¹⁰ Ω · cm is used.

  The contact member 8 is preferably rotated with a slight speed difference with respect to the rotation speed of the photosensitive drum 1, but is not limited thereto. Further, the contact member 8 is not limited to the case of rotating so as to move in the same direction at the position facing the photosensitive drum 1 as in this example, but may be rotated in the opposite direction.

  FIG. 2 is a schematic diagram illustrating the behavior of the toner while the image forming area portion of the photosensitive member passes and the behavior of the toner while the non-image forming region portion of the photosensitive member passes.

  In FIG. 2, 1 is a photosensitive member, 2 is a charging device, 3 is an image exposure device, 4 is a developing device, 5 is a transfer device, 6 is transfer paper, 8 is a contact member, and T is toner.

  (A) is a schematic diagram showing the behavior of the toner while the image forming area portion of the photoreceptor passes.

  The transfer residual toner T is taken into the contact member 8.

  (B) is a schematic diagram showing the behavior of the toner while the non-image forming area of the photoreceptor passes.

  The toner T taken (collected) by the contact member 8 is discharged onto the photoreceptor and is collected by the developing means 4.

<Photoconductor>
The photoreceptor used in the present invention has a protective layer on the outermost surface for the purpose of improving transferability and improving the disturbing effect of the contact member.

  The protective layer according to the present invention contains a component obtained by reacting a metal oxide particle surface-treated with a surface treatment agent having a reactive organic group and a curable compound.

  Hereinafter, the photoconductor will be described in detail.

  The layer structure of the photoreceptor is a layer structure in which a photosensitive layer and a protective layer are provided in this order on a support, and may be a layer structure having an intermediate layer between the support and the photosensitive layer as necessary.

<Support>
The support used in the present invention preferably has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or sheet, or a metal foil such as aluminum or copper. Examples include 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 paper. .

<Intermediate layer>
In the present invention, an intermediate layer having a barrier function and an adhesive function may be provided between the support 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 forming the intermediate layer, those in which inorganic particles (for example, titanium oxide particles) are well dispersed and the polyamide resin is dissolved are preferable. Ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t -C2-C4 alcohols such as butanol and sec-butanol are preferred because of their excellent solubility and coating performance for polyamide resins. In addition, examples of co-solvents that can be used in combination with the above-described solvents 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>
The photosensitive layer is not particularly limited, but a so-called multilayer 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 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, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, tetrahydrofuran , 1-dioxane, 1,3-dioxolane, pyridine, diethylamine and the like, 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, 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. Incidentally, 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 preferably 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, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, and 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, 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. For the antioxidant, those described in Japanese Patent Application No. 11-200135 and for the electronic conductive agent are described in Japanese Patent Application Laid-Open Nos. 50-137543 and 58-76483.

<Protective layer>
The protective layer according to the present invention is obtained by reacting a metal oxide particle surface-treated with a surface treatment agent having a reactive organic group (hereinafter also simply referred to as a surface-treated metal oxide particle) and a curable compound. Contains ingredients.

(Surface-treated metal oxide particles)
The surface-treated metal oxide can be produced by reacting a surface treatment agent having a reactive organic group with metal oxide particles.

  Examples of the surface treatment agent having a reactive organic group (hereinafter also simply referred to as a surface treatment agent) include compounds 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
Moreover, as a surface treating agent, you may use the compound which has the reactive group in which the following radical reaction is possible besides the compound of the said General formula (1).

  These compounds can be used alone or in admixture of two or more.

  The metal oxide particles are not particularly limited as long as they react with the surface treatment agent, and preferred examples include tin oxide particles, titanium oxide, and aluminum oxide.

  The number average primary particle size of the metal oxide particles is preferably 1 to 300 nm, more preferably 3 to 100 nm. When the particle size is small, the wear resistance is not sufficient, and when the particle size is large, the 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 metal oxide particles is a photographic image (excluding aggregated particles) taken with a scanning electron microscope (manufactured by JEOL Ltd.) with a magnification of 10000 times, and 300 particles randomly taken by a scanner. A) automatic image processing analyzer LUZEX AP (Nireco Corp.) software version Ver. It can be calculated and calculated using 1.32.

(Production method of surface-treated metal oxide particles)
The surface-treated metal oxide particles can be produced by a known production method.

  Hereinafter, the production method when using the compound represented by the general formula (1) as the surface treatment agent and tin oxide particles as the metal oxide particles will be described.

  The surface-treated tin oxide particles can be obtained by surface-treating the tin oxide particles using the compound represented by the general formula (1).

  In carrying out the surface treatment, using a wet media dispersion type apparatus using 0.1 to 100 parts by mass of the compound represented by the general formula (1) and 50 to 5000 parts by mass of the solvent with respect to 100 parts by mass of the tin oxide particles. It is preferable to process.

  Below, the surface treatment method which manufactures the tin oxide particle | grains surface-treated with the compound represented by General formula (1) more uniformly and finely is described.

  That is, the surface treatment of the tin oxide particles proceeds at the same time as the tin oxide particles are refined by wet grinding the slurry (suspension of solid particles) containing the tin oxide particles and the compound represented by the general formula (1). To do. Thereafter, the solvent is removed and the mixture is pulverized, so that tin oxide particles that are surface-treated with the compound represented by the general formula (1) can be obtained.

  Wet media dispersion type equipment used for surface treatment is to crush and crush the aggregated particles of alumina by filling beads in the container as media and rotating the stirring disk mounted perpendicular to the rotation axis at high speed. It is an apparatus having a step of dispersing, and as its configuration, there is no problem as long as it is a form that can sufficiently disperse tin oxide particles and surface-treat when tin oxide particles are subjected to surface treatment. For example, vertical and horizontal types Various styles such as continuous and batch type can be adopted. Preferably, a sand mill, an ultra visco mill, a pearl mill, a glen mill, a dyno mill, an agitator mill, a dynamic mill or the like can be used. These dispersive devices are pulverized and dispersed by impact crushing, friction, cutting, shear stress, etc., using a grinding medium 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 group can be obtained by surface treatment with the compound represented by the general formula (1).

(Components obtained by reacting surface-treated metal oxide particles with a curable compound)
The component obtained by reacting the surface-treated metal oxide particles with the curable compound (hereinafter also simply referred to as the component obtained by reacting) is obtained by reacting the surface-treated metal oxide particles with the curable compound. Can be produced.

  Examples of the curable compound include the following compounds having either an acryloyl group or a methacryloyl group.

In the present invention, a curable compound having a methacryloyl group is preferred. The curable compound having a methacryloyl group is preferable because CH ₃ of the methacryloyl group is bulkier than H of the acroyl group, so that the active gas can be prevented from coming to the double bond, and the active gas resistance is improved. It is because it can do.

  In the present invention, a curable compound having a charge transporting structure can be used.

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

  Below, the example of the curable compound which concerns on this invention is shown.

The curable compound is a compound having an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═C (CH ₃ ) CO—). Further, the number of Ac groups shown below represents the number of acryloyl groups or methacryloyl groups.

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

  Examples of the curable compound having a charge transporting structure include the following compounds.

  In the present invention, the curable compound preferably has 2 or more functional groups, and particularly preferably 4 or more. The methacrylic compound is a compound in which the ratio (Ac / M, methacryloyl group number / molecular weight) of the molecular weight M of the compound having a methacryloyl group and the number Ac of the methacryloyl group is greater than 0.005.

  By using a curable compound with Ac / M greater than 0.005, the crosslink density is increased, the wear resistance of the photoreceptor is improved, and the active gas resistance is also improved.

  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, cracks in the protective layer or an adverse effect on the life of the coating solution during production are likely to occur, and the occurrence of image flow and image blur may tend to increase. Therefore, it is rather desirable that Ac / M is smaller than 0.05.

  The protective 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 above composition.

(Reaction between surface-treated metal oxide particles and curable compound)
For the reaction between the surface-treated metal oxide particles and the curable compound, there are a method of reacting by electron beam cleavage, a method of adding a radical polymerization initiator or a cationic polymerizable initiator, and reacting with light or heat. 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 a curable compound that reacts and cures with light, 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. Further, as the compound which initiates the cationic polymerization, for example, 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

Examples of α-hydroxyacetophenone compounds

Examples of acylphosphine oxide compounds

Examples of other polymerization initiators

  Thermal polymerization initiators for curable compounds that react with heat and cure include ketone peroxide compounds, peroxyketal compounds, hydroperoxide compounds, dialkyl peroxide compounds, diacyl peroxide compounds, peroxide compounds. Examples thereof include carbonate compounds and peroxyester compounds. These thermal polymerization initiators are published in company product catalogs.

(Preparation of protective layer)
The protective layer according to the present invention is preferably a coating film in which the ratio of the metal oxide particles surface-treated with respect to 100 parts by mass of the curable compound is preferably 1 to 200 parts by mass, more preferably 30 to 120 parts by mass. Can be formed by reaction.

  In order to form a protective layer by reacting with light, a coating solution containing the above composition is applied on the photosensitive layer (charge transport layer in the case of a laminated type), and then the primary coating is used until the fluidity of the coating film is lost. After drying, a method of irradiating with ultraviolet rays to cause the coating film to react and cure, and in order to make the amount of volatile substances in the coating film a specified amount, a method of performing secondary drying is preferable.

  As a device for irradiating ultraviolet rays, a known device used for curing an ultraviolet curable resin can be used.

The amount of ultraviolet rays (mJ / cm ² ) that cures the coating film with ultraviolet rays is preferably controlled by the ultraviolet irradiation intensity and the irradiation time.

  In order to form a protective layer by reacting with heat, the above-mentioned thermal polymerization initiator is protected by mixing surface-treated metal oxide particles and a curable compound in the same manner as the photopolymerization initiator. A layer coating solution is prepared, and the coating solution is applied onto the photosensitive layer and then dried by heating to form the protective layer according to the present invention. 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 sclerosing | hardenable compounds, Preferably it is 0.5-10 mass parts.

  As a method for applying the coating solution, 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.

  Among these, the slide hopper method (a typical example is a circular slide hopper type) in which the film of the photosensitive layer under the protective layer is not dissolved as much as possible. The circular slide hopper type is described in detail, for example, in JP-A-58-189061.

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

<Preparation of protective layer containing charge transport material>
The protective layer according to the present invention can be formed by containing various charge transport materials in addition to the components obtained by the reaction.

  Various kinds of lubricant particles can be further added to the protective layer according to 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 protective 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 component obtained by the reaction. 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.

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

  Next, toner and developer will be described.

"toner"
The toner used in the present invention is not particularly limited, but a toner prepared by adding lubricant particles or abrasive particles as an external additive is preferable.

  By using the above toner, the wear on the surface of the photoconductor and the wear on the tip of the cleaning blade are suppressed, the cleaning property of the surface of the photoconductor and the intermediate transfer body is improved, and cleaning residue and toner filming hardly occur. It is preferable.

  Examples of the lubricant particles include aliphatic metal salts such as zinc stearate and calcium stearate that function as a solid lubricant. The addition ratio of the lubricant particles is preferably 0.1 to 0.4% by mass with respect to the toner.

  The abrasive particles are not particularly limited, but preferably include inorganic particles such as silica particles, titanium dioxide particles, and barium sulfate particles. The addition ratio of the abrasive particles is preferably 0.1 to 1.0% by mass with respect to the toner.

<Developer>
The developer used in the developing means is not particularly limited, but may be 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 particles may be used. can do.

  Further, it can be mixed with a carrier and used as a two-component developer. In this case, 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 diameter 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 mixing ratio of the carrier and the toner is preferably 2 to 10 parts by mass of the toner with respect to 100 parts by mass of the carrier.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this.

<< Production of photoconductor >>
A photoreceptor was prepared as follows.

<Surface-treated metal tin oxide particles>
Metal tin oxide particles (average particle size 30 nm) 100 parts by weight Exemplary compound (S-1) 5 parts by weight Isopropyl alcohol 500 parts by weight The above composition (solid particle suspension) is treated with a wet media dispersion device (alumina as a grinding medium). Was put into a sand grinder mill) and wet-treated for 5 hours to produce “surface-treated metal tin oxide particles”.

(Surface-treated metal titanium oxide particles)
“Surface-treated metal” was prepared in the same manner as in the preparation of the surface-treated metal tin oxide particles except that the metal tin oxide particles used in the preparation of the surface-treated metal tin oxide particles were changed to metal titanium oxide particles (particle size: 35 nm). Titanium oxide particles "were prepared.

(Surface-treated metal aluminum oxide particles)
“Surface treatment was performed in the same manner as the preparation of the surface-treated metal tin oxide particles, except that the metal tin oxide particles used in the preparation of the surface-treated metal tin oxide particles were changed to metal aluminum oxide particles (average particle size 25 nm). Metal aluminium oxide particles ”were prepared.

(Metal tin oxide particles) (for comparative example)
Untreated “metal tin oxide particles” were prepared as comparative examples.

<Preparation of Photoreceptor 1>
<Support 1>
The surface of a cylindrical aluminum support having a diameter of 60 mm was cut to prepare “Support 1” having a surface roughness Rz = 1.5 (μm).

<Intermediate layer 1>
Using the sand mill as a disperser, the following composition was batch-dispersed for 10 hours to prepare a dispersion. This dispersion was diluted twice with the same mixed solvent, allowed to stand overnight, and then filtered (filter; using a lymesh 5 μm filter manufactured by Nippon Pole Co., Ltd.) to prepare an intermediate layer coating solution.

Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part by mass Titanium oxide SMT500SAS (manufactured by Teica) 3 parts by mass Methanol 10 parts by mass The above intermediate layer coating solution is placed on the “support 1” to a dry film thickness of 2.0 μm. It was applied and dried by a dip coating method to form “intermediate layer 1”.

<Charge generation layer 1>
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 by mass Polyvinyl butyral resin (# 6000-C: electrochemical 10 parts by mass t-butyl acetate 700 parts by mass 4-methoxy-4-methyl-2-pentanone 300 parts by mass After mixing the above components, the mixture is dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. did. This coating solution was applied onto the “intermediate layer 1” by a dip coating method and dried to form “charge generation layer 1” having a dry film thickness of 0.3 μm.

<Charge transport layer 1>
Charge transport material: (4,4′-dimethyl-4 ″-(β-phenylstyryl) triphenylamine) 225 parts by mass Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts by mass Antioxidant (Irganox 1010: Ciba Geigy Japan) 6 parts by mass Tetrahydrofuran 1600 parts by mass Toluene 400 parts by mass Silicone oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass The above components were dissolved, mixed and dissolved to prepare a charge transport layer coating solution. The liquid was applied onto the “charge generation layer 1” using a circular slide hopper coating machine and dried to form “charge transport layer 1” having a dry film thickness of 20 μm.

<Protective layer 1>
Surface-treated metal tin oxide particles 8 parts by mass Curable compound (Exemplary Compound 42) 10 parts by mass Polymerization initiator (α-aminoalkylphenone) 10 parts by mass 1-propyl alcohol 40 parts by mass A protective layer coating solution was prepared by dissolution and dispersion. A protective layer was applied to the coating solution on the “charge transport layer 1” using a circular slide hopper coating machine. After coating, ultraviolet rays were irradiated for 5 minutes using a metal halide lamp to form “protective layer 1” having a dry film thickness of 2.0 μm, and “photosensitive member 1” was produced.

<Preparation of Photoreceptor 2>
A “photoreceptor 2” was produced in the same manner as the production of the photoreceptor 1 except that the protective layer 1 formed of the photoreceptor 1 was changed to the following “protective layer 2”.

<Protective layer 2>
Surface-treated tin oxide particles 8 parts by weight Curing compound (Exemplary Compound 32) 10 parts by weight Polymerization initiator (α-aminoalkylphenone) 10 parts by weight 1-propyl alcohol 40 parts by weight The above components are mixed and stirred and dissolved sufficiently -Dispersed to prepare a protective layer coating solution. The coating solution was first formed on the charge transport layer using a circular slide hopper coating machine. After coating, ultraviolet rays were irradiated for 5 minutes using a metal halide lamp to form “Protective layer 2” having a dry film thickness of 2.0 μm.

<Preparation of Photoreceptor 3>
A “photoreceptor 3” was produced in the same manner as the production of the photoreceptor 1 except that the protective layer 1 formed of the photoreceptor 1 was changed to the following “protective layer 3”.

<Protective layer 3>
Surface-treated tin oxide particles 8 parts by mass Resid Top PL-4852: manufactured by Gunei Chemical Co., Ltd. 9 parts by mass Polyvinylphenol resin (manufactured by Aldrich) 2 parts by mass Isopropyl alcohol 10 parts by mass 3,5-di-t-butyl-4 -Hydroxy (BHT) 0.2 mass part The said component was melt | dissolved and mixed and the coating-film liquid for protective layers was prepared. This coating solution is applied onto the “charge transport layer 1” by a dip coating method, dried at room temperature for 30 minutes, cured by heating at 150 ° C. for 1 hour, and a “protective layer having a thickness of 3.0 μm. 3 "was formed.

<Preparation of Photoreceptor 4>
A “photoreceptor 4” was produced in the same manner as the production of the photoreceptor 1 except that the protective layer 1 formed of the photoreceptor 1 was changed to the following “protective layer 4”.

<Protective layer 4>
Curable compound (Exemplary compound 42) 10 parts by mass Polymerization initiator (α-aminoalkylphenone) 10 parts by mass 1-propyl alcohol 40 parts by mass The above components are mixed and stirred, and sufficiently dissolved and dispersed. Produced. The coating solution was applied onto the “charge transport layer 1” using a circular slide hopper coating machine to form a coating film. Then, ultraviolet rays were irradiated for 5 minutes using a metal halide lamp to form “protective layer 4” having a dry film thickness of 2.0 μm.

<Preparation of Photoreceptor 5>
The “photoreceptor 5” was prepared in the same manner as the photoconductor 1 except that the surface-treated metal tin oxide particles used in the formation of the protective layer 1 of the photoconductor 1 were changed to “surface-treated metal titanium oxide particles”. Produced.

<Preparation of Photoreceptor 6>
The “photoreceptor 6” was prepared in the same manner as the preparation of the photoreceptor 1 except that the surface-treated metal tin oxide particles used in the formation of the protective layer 1 of the photoreceptor 1 were changed to “surface-treated metal aluminum oxide particles”. Produced.

<Preparation of photoconductor 7>
A “photoreceptor 6” was prepared in the same manner as the preparation of the photoreceptor 1 except that the protective layer 1 formed of the photoreceptor 1 was changed to the “protective layer 7” described below.

<Protective layer 7>
Surface-treated metal tin oxide particles 8 parts by weight Compound (RCTM-5) having a charge transport structure 10 parts by weight Polymerization initiator (α-aminoalkylphenone) 10 parts by weight 1-propyl alcohol 40 parts by weight The above components are mixed and stirred. The solution was sufficiently dissolved and dispersed to prepare a protective layer coating solution. A coating film was formed using a circular slide hopper coating machine on the photosensitive member in which the coating solution was previously prepared up to the charge transport layer. Thereafter, ultraviolet rays were irradiated for 5 minutes using a metal halide lamp to form a “protective layer 7” having a dry film thickness of 2.0 μm, thereby obtaining “photoreceptor 7”.

<Preparation of photoconductor 8>
A “photoreceptor 7” was produced in the same manner as the production of the photoreceptor 1 except that the protective layer 1 formed of the photoreceptor 1 was changed to the following “protective layer 8”.

<Protective layer 8>
Surface-treated metal tin oxide particles 8 parts by mass Curing compound (Exemplary Compound 42) 10 parts by mass Polymerization initiator (α-aminoalkylphenone) 10 parts by mass Charge transport compound (4,4′-dimethyl-4 ″-(β -Phenylstyryl) triphenylamine) 5 parts by mass 1-propyl alcohol 40 parts by mass The above components were mixed and stirred, and sufficiently dissolved and dispersed to prepare a protective layer coating solution. A coating film was formed on the top using a circular slide hopper coating machine, and then irradiated with ultraviolet rays for 5 minutes using a metal halide lamp to form a “protective layer 8” having a dry film thickness of 2.0 μm.

<Preparation of photoconductor 9>
The “photosensitive member 9” is the same as the preparation of the photosensitive member 1 except that the surface-treated metal tin oxide particles used in the preparation of the protective layer 1 of the photosensitive member 1 are changed to “metal tin oxide particles” without surface treatment. Was made.

<Preparation of Photoreceptor 10>
In the production of the photoconductor 1, the case where the protective layer 1 is not provided is referred to as “photoconductor 10”.

  Table 1 shows the presence or absence of the protective layer of the photoreceptor 1 and the composition of the protective layer.

<Production of developer>
100 parts by mass of colored particles having a median particle diameter (D ₅₀ ) of 6.0 μm on a number basis, 0.1 parts by mass of silica particles having a number average primary particle diameter of 50 nm, and titanium dioxide particles having a number average primary particle diameter of 20 nm 5 parts by mass and 0.2 parts by mass of zinc stearate particles having a number average primary particle diameter of 50 nm were externally added to prepare a “toner”.

  A “developer” was prepared by mixing a ferrite carrier having a number average primary particle diameter of 60 μm so that the concentration of the “toner” was 4% by mass.

《Image evaluation》
In the image evaluation, the “image forming apparatus” shown in FIG. 1 is sequentially mounted with the photoconductor and the developer prepared above, and a character image (3 point, 5 point character) with a printing rate of 7%, a human face Original images, each of which is a quarter of a photo (dot image including halftone), solid white image, and solid black image, are placed on neutral paper (64 g / m ² ) of A4 size at normal temperature and humidity (20 ° C) , 50% RH), 100,000 sheets were printed.

(Image memory)
After the completion of printing 100,000 sheets, the image memory is a character image with a printing rate of 7% in the upper half of A3 size and a halftone image in the lower half (reflection density 0) in an environment of normal temperature and humidity (20 ° C., 50% RH). The original document of 4) was printed on 2500 sheets, and the 2500th image was visually evaluated.

Evaluation criteria ◎: No character image memory is recognized in the halftone image portion ○: Character image memory is recognized slightly in the halftone image portion, but there is no practical problem ×: Memory of the character image is recognized in the halftone image portion There are practical problems.

  Table 2 shows the evaluation results.

  From Table 2, it can be seen that “Examples 1 to 6” according to the present invention can obtain a high-quality print image without any problem in any of the evaluation items. On the other hand, “Comparative Examples 1 to 4” for comparison shows that there is a problem in any of the evaluation items.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging means 3 Image exposure means 4 Developing means 5 Transfer means 6 Recording medium 8 Contact member

Claims (4)

A charging unit for applying a charging potential on the photosensitive member, an exposure unit for exposing the photosensitive member to which the charging potential has been applied to form an electrostatic latent image, and a development for developing the electrostatic latent image into a toner image And a transfer means for transferring the toner image to the transfer body, contacting the photoreceptor at a position downstream from the transfer means and upstream from the charging means, and temporarily collecting the residual toner on the photoreceptor. In an image forming apparatus having a conductive contact member having a function of discharging the toner that has been discharged onto the photosensitive member, and having a function of collecting the toner discharged on the photosensitive member simultaneously with the development.
The photoreceptor has a protective layer on the outermost surface;
An image forming apparatus, wherein the protective layer contains a component obtained by reacting a metal oxide particle surface-treated with a surface treating agent having a reactive organic group and a curable compound. The image forming apparatus according to claim 1, wherein the protective layer does not contain a compound having a charge transporting structure. The image forming apparatus according to claim 1, wherein the curable compound is a compound having either an acryloyl group or a methacryloyl group. The image forming apparatus according to claim 1, wherein the surface treatment agent is a surface treatment agent having either an acryloyl group or a methacryloyl group.

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