# US 2026/0133508 A1 · Electrophotographic photoreceptor, process cartridge, and image forming apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0133508 A1 - Document ID: US20260133508A1 - Status: Published application - Kind: A1 - Application number: 19/351,253 - Filed: 2025-10-06 - Published: 2026-05-14 - Earliest claimed: 2024-11-11 - Assignees: FUJIFILM Business Innovation Corp. - Applicants: FUJIFILM Business Innovation Corp. - Inventors: Masahiro IWASAKI; Tomoya SASAKI; Kenta IDE; Yoichi KIGOSHI; Fuyuki KANO; Yuki OYAMADA; Kohei TAKAOKA; Kosuke NARITA - Web page: https://patentgrep.com/patent/US20260133508A1 ## CPC - G03G 5/056: {Polyesters} - C08L 67/03: the dicarboxylic acids and dihydroxy compounds having the carboxyl- and the hydroxy groups directly linked to aromatic rings - C08L 69/00: Compositions of polycarbonates; Compositions of derivatives of polycarbonates - G03G 5/04: Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor - G03G 5/047: characterised by the charge-generation layers or charge transport layers {(G03G5/0433 and G03G5/0436 take precedence)} - G03G 5/0564: {Polycarbonates} - G03G 5/0605: {Carbocyclic compounds} - G03G 21/0017: {Details relating to the internal structure or chemical composition of the blades} - G03G 21/1814: {Details of parts of process cartridge, e.g. for charging, transfer, cleaning, developing (G03G21/1835 takes precedence)} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract An electrophotographic photoreceptor includes a conductive substrate, a charge generation layer disposed on the conductive substrate, and a charge transport layer disposed on the charge generation layer, in which the charge transport layer contains a phenolic compound, a polyarylate resin, a polycarbonate resin, and a charge transport material, and each of a vector distance DISHT (J/cm3)1/2 between an HSP value of the charge transport material and an HSP value of the polyarylate resin, and a vector distance DISPC (J/cm3)1/2 between the HSP value of the polycarbonate resin and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, satisfies Expression (1) and Expression (2), D ⁢ I ⁢ S H ⁢ T ≤ 3.9 , Expression ⁢ ( 1 ) 9.2 ≤ D ⁢ I ⁢ S P ⁢ C < 1 ⁢ 2 . 0 . Expression ⁢ ( 2 ) ## Claims ### Claim 1 An electrophotographic photoreceptor comprising: a conductive substrate; a charge generation layer disposed on the conductive substrate; and a charge transport layer disposed on the charge generation layer, wherein the charge transport layer contains a phenolic compound, a polyarylate resin, a polycarbonate resin, and a charge transport material, and each of a vector distance DISHT (J/cm3)1/2 between an HSP value of the charge transport material and an HSP value of the polyarylate resin, and a vector distance DISPC (J/cm3)1/2 between the HSP value of the polycarbonate resin and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, satisfies Expression (1) and Expression (2), D ⁢ I ⁢ S H ⁢ T ≤ 3.9 , Expression ⁢ ( 1 ) 9.2 ≤ D ⁢ I ⁢ S P ⁢ C < 1 ⁢ 2 . 0 . Expression ⁢ ( 2 ) ### Claim 2 (depends on 1) The electrophotographic photoreceptor according to claim 1, wherein a vector distance DISOHCT (J/cm3)1/2 between an HSP value of the phenolic compound and the HSP value of the charge transport material, which are calculated based on a Hansen solubility parameter, satisfies Expression (3), 3. 6 ≤ D ⁢ I ⁢ S OHCT ≤ 7 . 0 . Expression ⁢ ( 3 ) ### Claim 3 (depends on 1) The electrophotographic photoreceptor according to claim 1, wherein a vector distance DISOHPA (J/cm3)1/2 between an HSP value of the phenolic compound and the HSP value of the polyarylate resin, which are calculated based on a Hansen solubility parameter, satisfies Expression (4), 5 . 5 ≤ D ⁢ I ⁢ S OHPA ≤ 8. . Expression ⁢ ( 4 ) ### Claim 4 (depends on 1) The electrophotographic photoreceptor according to claim 1, wherein a hydrogen bonding term δHOH (J/cm3)1/2 of the phenolic compound, which is calculated based on a Hansen solubility parameter, satisfies Expression (5), 3. 5 ≤ δ ⁢ H O ⁢ H ≤ 7 . 7 . Expression ⁢ ( 5 ) ### Claim 5 (depends on 1) The electrophotographic photoreceptor according to claim 1, wherein the phenolic compound includes a hindered phenolic compound. ### Claim 6 (depends on 5) The electrophotographic photoreceptor according to claim 5, wherein the phenolic compound includes a phenolic compound having 3 or fewer phenolic functional groups and a molecular weight of 300 or more. ### Claim 7 (depends on 1) The electrophotographic photoreceptor according to claim 1, wherein the polyarylate resin has a dicarboxylic acid unit represented by Formula (A) and a diol unit represented by Formula (B), in Formula (A), ArA1 and ArA2 are each independently an aromatic ring which may have a substituent, LA is a single bond or a divalent linking group, and nA1 is 0, 1, or 2, in Formula (B), ArB1 and ArB2 are each independently an aromatic ring which may have a substituent, LB is a single bond, an oxygen atom, a sulfur atom, or —C(Rb1)(Rb2)—, and nB1 is 0, 1, or 2, where Rb1 and Rb2 are each independently a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms, an aryl group having 6 or more and 12 or less carbon atoms, or an aralkyl group having 7 or more and 20 or less carbon atoms, and Rb1 and Rb2 may be bonded to each other to form a cyclic alkyl group. ### Claim 8 (depends on 1) The electrophotographic photoreceptor according to claim 1, wherein the polyarylate resin and the polycarbonate resin each have a constitutional unit including biphenyl represented by Formula (BP), in Formula (BP), j is an integer of 0 or greater and 4 or less, j pieces of R1's are each independently a methyl group or an ethyl group, k is an integer of 0 or greater and 4 or less, and k pieces of R2's are each independently a methyl group or an ethyl group. ### Claim 9 (depends on 1) A process cartridge comprising: the electrophotographic photoreceptor according to claim 1, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 10 (depends on 2) A process cartridge comprising: the electrophotographic photoreceptor according to claim 2, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 11 (depends on 3) A process cartridge comprising: the electrophotographic photoreceptor according to claim 3, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 12 (depends on 4) A process cartridge comprising: the electrophotographic photoreceptor according to claim 4, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 13 (depends on 5) A process cartridge comprising: the electrophotographic photoreceptor according to claim 5, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 14 (depends on 6) A process cartridge comprising: the electrophotographic photoreceptor according to claim 6, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 15 (depends on 7) A process cartridge comprising: the electrophotographic photoreceptor according to claim 7, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 16 (depends on 8) A process cartridge comprising: the electrophotographic photoreceptor according to claim 8, wherein the process cartridge is attachable to and detachable from an image forming apparatus. ### Claim 17 (depends on 1) An image forming apparatus comprising: the electrophotographic photoreceptor according to claim 1; a charging device that charges a surface of the electrophotographic photoreceptor; an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the electrophotographic photoreceptor; a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a developer containing a toner to form a toner image; and a transfer device that transfers the toner image to a surface of a recording medium. ### Claim 18 (depends on 17) The image forming apparatus according to claim 17, further comprising: a cleaning device that has a cleaning blade coming into contact with the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor. ### Claim 19 (depends on 18) The image forming apparatus according to claim 18, wherein a contact portion of the cleaning blade coming into contact with the electrophotographic photoreceptor contains a polyurethane rubber obtained by polymerizing at least a polyol component and a polyisocyanate component, and the contact portion is formed of a member having a ratio M100/Re of a 100% modulus M100 (MPa) to a rebound resilience Re (%) of 0.25 or more, the rebound resilience Re of less than 25%, and a tensile stress at a 200% strain of 15 MPa or more. ### Claim 20 (depends on 19) The image forming apparatus according to claim 19, wherein the ratio M100/Re is 0.28 or more and 1.0 or less.