Electrophotographic photoreceptor, process cartridge, and image forming apparatus
View Patent ↗A negative-charge type electrophotographic photoreceptor includes a conductive substrate; an undercoat layer which includes a binder resin and metal oxide particles and in which the work function is from 4.0 eV to 4.7 eV; a charge generation layer in which a difference between the work functions of the charge generation layer and the undercoat layer is from −4 eV to 0 eV; and a charge transport layer which is provided on the charge generation layer.
1. A negative-charge type electrophotographic photoreceptor, comprising:
a conductive substrate;
an undercoat layer having a thickness of from 20 μm to 50 μm, and a work function of from 4.0 eV to 4.7 eV, the undercoat layer comprising:
a binder resin,
metal oxide particles, a content of the metal oxide particles being from 10% by weight to 80% by weight with respect to the binder resin, and
an electron-accepting compound having an anthraquinone structure, a content of the electron-accepting compound being from 0.01% by weight to 20% by weight with respect to the metal oxide particles;
a charge generation layer comprising a binder resin and a charge generation material, wherein a difference between a work function of the charge generation layer and the work function of the undercoat layer is from −4 eV to 0 eV; and
a charge transport layer which is provided on the charge generation layer.
2. The electrophotographic photoreceptor according to claim 1 , wherein the work function of the undercoat layer is from 4.2 eV to 4.7 eV.
3. The electrophotographic photoreceptor according to claim 1 , wherein the difference between the work function of the charge generation layer and the work function of the undercoat layer is from −3.5 eV to −0.05 eV.
4. The electrophotographic photoreceptor according to claim 1 , wherein the work function of the charge generation layer is from 4.1 eV to 4.5 eV.
5. The electrophotographic photoreceptor according to claim 1 , wherein a volume average particle diameter of the metal oxide particles is in a range of from 50 nm to 500 nm.
6. The electrophotographic photoreceptor according to claim 1 , wherein the electron-accepting compound is a compound selected from the group consisting of anthraquinone, alizarin, quinizarin, anthrarufin, and purpurin.
7. A process cartridge, comprising:
the electrophotographic photoreceptor according to claim 1 ; and
at least one unit selected from (A) a charging unit that charges a surface of the electrophotographic photoreceptor, (B) a latent image forming unit that forms an electrostatic latent image on a charged surface of the electrophotographic photoreceptor, (C) a developing unit that develops the electrostatic latent image, which is formed on the surface of the electrophotographic photoreceptor, using a toner to form a toner image, (D) a transfer unit that transfers the toner image, which is formed on the surface of the electrophotographic photoreceptor, onto a recording medium, and (E) a cleaning unit that cleans the electrophotographic photoreceptor.
8. An image forming apparatus, comprising:
the electrophotographic photoreceptor according to claim 1 ;
a charging unit that charges a surface of the electrophotographic photoreceptor;
a latent image forming unit that forms an electrostatic latent image on a charged surface of the electrophotographic photoreceptor;
a developing unit that develops the electrostatic latent image, which is formed on the surface of the electrophotographic photoreceptor, using a toner to form a toner image; and
a transfer unit that transfers the toner image, which is formed on the surface of the electrophotographic photoreceptor, onto a recording medium.
9. The image forming apparatus according to claim 8 , wherein the work function of the undercoat layer of the electrophotographic photoreceptor is from 4.2 eV to 4.7 eV.
10. The image forming apparatus according to claim 8 , wherein the difference between the work of the charge generation layer and the work function of the undercoat layer of the electrophotographic photoreceptor is from −3.5 eV to −0.05 eV.
11. The electrophotographic photoreceptor according to claim 1 , wherein the metal oxide particles are particles of zinc oxide, titanium oxide, tin oxide, or indium oxide.
12. The electrophotographic photoreceptor according to claim 1 , wherein the charge generation material is hydroxygallium phthalocyanine or chlorogallium phthalocyanine.
13. The electrophotographic photoreceptor according to claim 1 , wherein the binder resin of the charge generation layer is polyvinyl butyral or vinyl chloride-vinyl acetate copolymer.