JP-7855949-B2 - Electrophotographic photoreceptor, image forming apparatus, and image forming method

Inventors

• 藤田 俊行
• 西村 一国

Assignees

• コニカミノルタ株式会社

Dates

Publication Date

20260511

Application Date

20220704

Claims (8)

1. A conductive support, Photosensitive layer, A protective layer, An electrophotographic photoreceptor containing these elements stacked in this order, The protective layer is formed from a cured product of a composition comprising a charge-transporting compound having a radical polymerizable functional group and metal oxide particles surface-treated with a surface treatment agent having a silicone chain as a side chain. Electrophotographic photoreceptor.
2. The electrophotographic photoreceptor according to claim 1, wherein the metal oxide particles are further surface-treated with a surface treatment agent having radical polymerizable functional groups.
3. The electrophotographic photoreceptor according to claim 1 or 2, wherein the charge transporting compound having the radical polymerizable functional group is a compound represented by the following general formula (1). (In general formula (1), Ar1 and Ar2 independently exhibit a structure represented by general formula (2), Ar 3 represents a structure that can be expressed by general formula (2) or general formula (3), D independently represents a structure represented by -(-( CH2 ) d- (O-( CH2 ) f- ) e -O-CO-C( CH3 )= CH2 ) or -(-( CH2 ) d- (O-( CH2 ) f- ) e -O-CO-CH= CH2 ), where d and f independently represent integers between 0 and 5 (inclusive), and e represents an integer of 0 or 1. c1 to c3 independently represent integers 0, 1, or 2. When Ar3 exhibits the structure represented by general formula (2), the total number of D atoms in the compound is 1 or 2. When Ar3 exhibits the structure represented by general formula (3), the total number of D atoms in the compound is 1. (In general formulas (2) and (3), R1 and R2 independently represent a functional group or atom selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. However, in general formula (3), two R2s may be bonded together to form a cyclic structure. (t independently represents an integer between 1 and 3, inclusive.)
4. The electrophotographic photoreceptor according to claim 3, wherein the compound represented by the general formula (1) is a compound in which Ar3 exhibits the structure represented by the general formula (3).
5. The electrophotographic photoreceptor according to claim 3, wherein the compound represented by the general formula (1) is a compound in which the sum of c1 to c3 is 1, e in the structure represented by D is 1, and at least one of d and f is an integer between 1 and 4.
6. The electrophotographic photoreceptor according to claim 1 or 2, wherein the metal oxide particles are silica particles.
7. An image forming apparatus having an electrophotographic photoreceptor as described in claim 1 or 2.
8. A step of bringing a charging roller into contact with the electrophotographic photoreceptor according to claim 1 or 2 to charge the surface of the electrophotographic photoreceptor, The steps include: applying toner to the surface of the charged electrophotographic photoreceptor; A step of transferring the applied toner to a recording medium, An image forming method having the following characteristics.

Description

This invention relates to an electrophotographic photoreceptor, an image forming apparatus, and an image forming method. In electrophotographic image forming apparatuses, an electrophotographic photoreceptor (hereinafter also simply referred to as "photoreceptor") is used to form an electrostatic latent image corresponding to the image to be formed. In an electrophotographic image forming apparatus, first, light is irradiated onto the photoreceptor, whose surface has been charged, to form an electrostatic latent image. Next, toner is supplied to the photoreceptor to form a toner image corresponding to the electrostatic latent image. Finally, the toner image is transferred to a recording medium such as paper and fixed. The photoconductor requires cleaning to remove any remaining toner from its surface using a cleaning blade or similar tool. This cleaning process wears down the surface of the photoconductor, necessitating periodic replacement. However, there is a demand for improving the wear resistance of the photoconductor to extend its lifespan and reduce the frequency of replacement. It is known that using a cured layer formed by curing a charge-transporting compound having radical polymerizable groups as a protective layer on the outermost surface can improve the abrasion resistance of a photoreceptor (for example, Patent Document 1). Japanese Patent Publication No. 2014-105223 Figure 1 is a partial cross-sectional view showing an exemplary layer configuration of an electrophotographic photoreceptor according to one embodiment of the present invention.Figure 2 is a schematic diagram showing the configuration of an image forming apparatus according to one embodiment of the present invention. 1. Electrophotographic Photoreceptor Figure 1 is a partial cross-sectional view showing an exemplary layer configuration of an electrophotographic photoreceptor 100 according to one embodiment of the present invention. The photoreceptor 100 in this embodiment has a conductive support 110, an intermediate layer 120, a charge generation layer 130, a charge transport layer 140, and a protective layer 150, which are stacked in this order. 1-1. Conductive support 110 The conductive support 110 supports the intermediate layer 120, the charge generation layer 130, the charge transport layer 140, and the protective layer 150, and is a member whose surface, at least, is in contact with the intermediate layer 120 and is conductive. Examples of the conductive support 110 include a metal drum or sheet, a plastic film having laminated metal foil, a plastic film having a layer of vapor-deposited conductive material, a metal member having a conductive layer coated with a conductive material or a paint consisting of a conductive material and a binder resin, a plastic film, and paper. Examples of the metal include aluminum, copper, chromium, nickel, zinc, and stainless steel. Examples of the conductive material include the metal, indium oxide, and tin oxide. From the viewpoint of improving the processability and robustness of the conductive support 110 and making the conductive support 110 lighter, the metal is preferably aluminum. The thickness of the peripheral wall of the conductive support 110 can be, for example, about 0.1 mm. 1-2. Middle layer 120 The intermediate layer 120 is positioned between the conductive support 110 and the charge generation layer 130 and has functions such as removing charge (typically electrons) from the charge generation layer 130 to the conductive support 110, suppressing charge (typically holes) leakage from the conductive support 110 to the charge generation layer 130, and providing adhesion. The intermediate layer 120 includes a binder resin for the intermediate layer and conductive particles. Examples of binder resins for the intermediate layer include polyamide resins, casein, polyvinyl alcohol resins, nitrocellulose, ethylene-acrylic acid copolymers, vinyl chloride resins, vinyl acetate resins, polyurethane resins, and gelatin. The binder resin for the intermediate layer may be one type or more. Examples of the conductive particles mentioned above include metal oxide particles containing aluminum oxide (alumina), aluminum hydroxide, zinc oxide, titanium oxide, tin oxide, antimony oxide, zirconium oxide, indium oxide, and bismuth oxide; tin-doped indium oxide; antimony-doped tin oxide; and particles of conductive materials such as zirconium oxide. From the viewpoint of further improving the charge removal efficiency to the conductive support side in the intermediate layer 120, the conductive material is preferably an n-type semiconductor. Examples of the conductive material as an n-type semiconductor include titanium oxide, zinc oxide, aluminum oxide, aluminum hydroxide, and tin oxide. Furthermore, from the viewpoint of improving the conductivity of the intermediate layer 120 and the dispersibility of conductive particles in the intermediate layer 120, the conductive material is preferably titaniu