Electrophotographic photoreceptor, process cartridge, image forming apparatus, and image forming method

1. An electrophotographic photoreceptor comprising:

a substrate;

an undercoat layer provided on the substrate and containing:

a binder resin, and

a tin-zinc complex oxide powder dispersed in the binder resin and having a volume resistivity of about 2×10 9 Ω·cm or less,

wherein the tin-zinc complex oxide powder is an amorphous material; and

a photosensitive layer provided on the undercoat layer.

2. The electrophotographic photoreceptor according to claim 1 , wherein the tin-zinc complex oxide powder is a powder heat-treated at a temperature of from about 450° C. to about 900° C. under reduced pressure.

3. The electrophotographic photoreceptor according to claim 2 , wherein the degree of vacuum in the heat treatment is from about 10 Pa to about 3 kPa.

4. The electrophotographic photoreceptor according to claim 1 , wherein the volume average particle size of the tin-zinc complex oxide powder is within a range of from about 20 nm to about 200 nm.

5. The electrophotographic photoreceptor according to claim 1 , wherein the tin-zinc complex oxide powder is contained in the undercoat layer within a range of from about 10% by weight to about 95% by weight.

6. The electrophotographic photoreceptor according to claim 1 , wherein the tin-zinc complex oxide powder has a volume resistivity of from about 1×10 6 Ω·cm or less.

7. The electrophotographic photoreceptor according to claim 1 , wherein the tin-zinc complex oxide powder is ZnSnO 3 or Zn 2 SnO 4 .

8. A process cartridge for an image forming apparatus comprising:

the electrophotographic photoreceptor according to claim 1 ; and

at least one device selected from a charging device that charges the electrophotographic photoreceptor, a latent image forming device that forms an electrostatic latent image on the surface of a charged electrophotographic photoreceptor, a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a toner to form a toner image, a transfer device that transfers the toner image formed on the surface of the electrophotographic photoreceptor to a recording medium, and a cleaning device that cleans the surface of the electrophotographic photoreceptor.

9. The process cartridge for an image forming apparatus according to claim 8 , wherein the tin-zinc complex oxide powder of the electrophotographic photoreceptor has a volume average particle size within a range of from about 20 nm to about 200 nm.

10. An image forming apparatus comprising:

the electrophotographic photoreceptor according to claim 1 ;

a charging device that charges the electrophotographic photoreceptor;

a latent image forming device that forms an electrostatic latent image on the surface of a charged electrophotographic photoreceptor;

a developing device that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor with a toner to form a toner image; and

a transfer device that transfers the toner image formed on the surface of the electrophotographic photoreceptor to a recording medium.

11. The image forming apparatus according to claim 10 , wherein the tin-zinc complex oxide powder of the electrophotographic photoreceptor is an amorphous material.

12. The image forming apparatus according to claim 10 , wherein the tin-zinc complex oxide powder of the electrophotographic photoreceptor has a volume average particle size within a range of from about 20 nm to about 200 nm.

13. An image forming method comprising:

charging the surface of an electrophotographic photoreceptor;

forming an electrostatic latent image on the surface of the electrophotographic photoreceptor;

developing the electrostatic latent image formed on the surface of the electrophotographic photoreceptor using developer to form a toner image; and

transferring the developed toner image developed to a transfer medium,

wherein the electrophotographic photoreceptor is the electrophotographic photoreceptor according to claim 1 .

14. The image forming method according to claim 13 , wherein the tin-zinc complex oxide powder of the electrophotographic photoreceptor has a volume average particle size within a range of from about 20 nm to about 200 nm.