JP-7856214-B2 - Electrophotographic photoreceptor, process cartridge, and image forming apparatus

JP7856214B2JP 7856214 B2JP7856214 B2JP 7856214B2JP-7856214-B2

Inventors

杉本和隆
窪嶋大輔
寺岡克矩
大塚裕生
森川良太

Assignees

京セラドキュメントソリューションズ株式会社

Dates

Publication Date: 20260511
Application Date: 20240520
Priority Date: 20230323

Claims (14)

An electrophotographic photoreceptor comprising a conductive substrate, a photosensitive layer, and a protective layer, The photosensitive layer contains a charge generating agent and a hole transporting agent, The protective layer is the outermost layer of the electrophotographic photoreceptor and contains a resin having halogen groups. The mass ratio of halogen atoms contained in the protective layer to the mass of the protective layer is 2% by mass or more and 20% by mass or less. The Martens hardness of the protective layer is 280 N/ mm² or more and 450 N/ mm² or less . The resin comprises a first repeating unit, a second repeating unit, and a third repeating unit. The first repeating unit does not have the halogen group, The second repeating unit has the halogen group and does not have a siloxane bond-containing group. The third repeating unit is an electrophotographic photoreceptor having the halogen group and the siloxane bond-containing group .
The mass ratio of the second repeating unit to the mass of the resin is 3.0% by mass or more and 42.0% by mass or less. The electrophotographic photoreceptor according to claim 1 , wherein the mass ratio of the third repeating unit to the mass of the resin is 1.0% by mass or more and 45.0% by mass or less.
The electrophotographic photoreceptor according to claim 1 , wherein the second repeating unit includes a repeating unit derived from a compound represented by formula (EB-1). (In formula (EB-1) above, R1 represents the group represented by formula (b1), and R2 represents a hydrogen atom or a methyl group.) (In formula (b1) above, m represents 0 or 1, n represents an integer between 1 and 3, R3 represents a hydrogen atom or a fluorine atom, and * represents a bond.)
The electrophotographic photoreceptor according to claim 1 , wherein the third repeating unit includes repeating units derived from a fluorosilicone-modified acrylic polymer having a vinyl group.
The electrophotographic photoreceptor according to claim 1 , wherein the first repeating unit includes a repeating unit derived from a compound represented by formula (EA-3) and a repeating unit derived from a compound represented by formula (EA-4).
The electrophotographic photoreceptor according to claim 1, wherein the thickness of the protective layer is 1 μm or more and 4 μm or less.
The electrophotographic photoreceptor according to claim 1, wherein the hole transport agent contained in the photosensitive layer comprises at least one of the compounds represented by formulas (1) and (2). (In formula (1) above, R 41 , R 42 , R 43 , R 44 , R 45 , and R 46 each independently represent an alkyl group having 1 to 8 carbon atoms, or a phenyl group; R 47 and R 48 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; e 1 , e 2 , e 3 , and e 4 each independently represent an integer between 0 and 5, and e 5 and e 6 each independently represent an integer between 0 and 4.) In formula (2) above, R 50 , R 51 , and R 54 each independently represent an alkyl group having 1 to 8 carbon atoms, or a phenyl group; R 52 and R 53 each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 8 carbon atoms; and f 3 , f 4 , and f 5 each independently represent an integer between 0 and 5.
The electrophotographic photoreceptor according to claim 1, wherein the charge generating agent contained in the photosensitive layer comprises titanylphthalocyanine.
The photosensitive layer includes a charge generation layer and a charge transport layer. The charge generating layer contains the charge generating agent, The charge transport layer contains the hole transport agent, The electrophotographic photoreceptor according to claim 1, wherein the content of the hole transporter in the charge transport layer is 40% by mass or more relative to the mass of the charge transport layer.
At least one selected from the group consisting of a charging device, an exposure device, a developing device, a transfer device, a cleaning member, a friction roller, and a static elimination device, A process cartridge comprising an electrophotographic photoreceptor as described in claim 1.
Image carrier and, A charging device for charging the surface of the image carrier, An exposure apparatus for exposing the surface of the charged image carrier to form an electrostatic latent image on the surface of the image carrier, A developing apparatus that supplies toner to the surface of the image carrier and develops the electrostatic latent image as a toner image, The system comprises a transfer device for transferring the toner image from the image carrier to the transfer target, An image forming apparatus wherein the image carrier is the electrophotographic photoreceptor described in claim 1.
A cleaning member for collecting the toner adhering to the surface of the image carrier, The image forming apparatus according to claim 11 , further comprising at least one selected from the group consisting of a friction roller for rubbing the surface of the image carrier and a static elimination device for removing static electricity from the surface of the image carrier.
The image forming apparatus according to claim 11 , wherein the charging device is a charging roller.
The image forming apparatus according to claim 11 , wherein the developing apparatus supplies the toner, which has been charged by friction with the carrier, to the surface of the image carrier.

Description

This invention relates to an electrophotographic photoreceptor, a process cartridge, and an image forming apparatus. When images are repeatedly formed using an image forming apparatus equipped with an electrophotographic photoreceptor, the electrophotographic photoreceptor may gradually wear down. To suppress wear and extend the lifespan of the electrophotographic photoreceptor, a hard protective layer may be provided on the surface of the electrophotographic photoreceptor. For example, the electrophotographic photoreceptor described in Patent Document 1 consists of a substrate and a plurality of layers formed on the substrate. The protective layer, which is the outermost layer of the plurality of layers, is composed of a crosslinking material. This crosslinking material is formed using a coating solution containing at least one type of curable charge-transporting material. The elastic deformation rate of the protective layer, which is the outermost layer, is 45% to 55%, and the universal hardness is 185 N/ mm² to 210 N/ mm² . Japanese Patent Publication No. 2010-224304 This is a partial cross-sectional view of a single-layer electrophotographic photoreceptor, which is an example of an electrophotographic photoreceptor according to the first embodiment of the present invention.This is a partial cross-sectional view of a single-layer electrophotographic photoreceptor, which is an example of an electrophotographic photoreceptor according to the first embodiment of the present invention.This is a partial cross-sectional view of a stacked electrophotographic photoreceptor, which is an example of an electrophotographic photoreceptor according to the first embodiment of the present invention.This is a partial cross-sectional view of a stacked electrophotographic photoreceptor, which is an example of an electrophotographic photoreceptor according to the first embodiment of the present invention.This is a partial cross-sectional view of a stacked electrophotographic photoreceptor, which is an example of an electrophotographic photoreceptor according to the first embodiment of the present invention.This figure shows an example of an image forming apparatus according to a second embodiment of the present invention.Figure 6 shows an example of the configuration of a developing apparatus. The embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below and can be implemented with appropriate modifications within the scope of the object of the present invention. First, let's explain the terminology used in this specification. Unless otherwise specified, viscosity-average molecular weight is the value measured according to JIS (Japanese Industrial Standards) K7252-1:2016. Acrylics and methacrylics are sometimes collectively referred to as "(meth)acrylics". Unless otherwise specified, hydroxyl value is the value measured according to JIS (Japanese Industrial Standards) K0070-1992. Unless otherwise specified, number-average primary particle diameter is the number-average value of the equivalent circle diameter (Heywood diameter: the diameter of a circle having the same area as the projected area of the primary particle) of primary particles measured using a scanning electron microscope. For example, the number-average primary particle diameter is the number-average value of the equivalent circle diameter of 100 primary particles. Unless otherwise specified, glass transition temperature (Tg) is the value measured according to JIS (Japanese Industrial Standards) K7121-2012 using a differential scanning calorimeter (DSC-6220, manufactured by Seiko Instruments Inc.). In an endothermic curve measured by a differential scanning calorimeter (vertical axis: heat flow (DSC signal), horizontal axis: temperature), the temperature at the inflection point due to the glass transition (specifically, the temperature at the intersection of the baseline extrapolation line and the falling line extrapolation line) corresponds to Tg (glass transition point). Unless otherwise specified, the BET specific surface area is the value measured by the BET method using nitrogen adsorption, in accordance with "JIS (Japanese Industrial Standards) Z8830:2001 Method for measuring the specific surface area of powders (solids) by gas adsorption". The term "system" may be added after the compound name to comprehensively refer to the compound and its derivatives. Also, when "system" is added after the compound name to represent a polymer name, it means that the repeating units of the polymer originate from the compound or its derivative. Furthermore, "general formula" and "chemical formula" are collectively referred to as "formula". In the explanation of a formula, "each independently" means that they may represent the same group or different groups. "At least one of a, b, and c" and "at least one of a, b, and c" mean "at least one selected from the group consisting of