Electrophotographic photoreceptor, image forming apparatus, and process cartridge

1. An electrophotographic photoreceptor comprising:

a substrate;

a photosensitive layer that is provided on the substrate; and

a surface layer that is provided on the photosensitive layer, contains fluororesin particles, is a single layer having a thickness of 3 μm or greater, and has a cross-section, taken along a thickness direction thereof, which satisfies Expressions (1), (2), and (3) below:

0 ≦A 1 ≦0.2 ×A 4   Expression (1)

0.2 ×A 4 <A 2 ≦0.6 ×A 4   Expression (2)

0.6 ×A 4 <A 3   Expression (3)

wherein,

A 1 represents the ratio (%) of the area of the fluororesin particles to the total area of a first region in cross-section, in which the first region is located in a distance range of greater than or equal to 0.2 μm and less than 0.5 μm from the outermost surface of the surface layer to the substrate side;

A 2 represents the ratio (%) of the area of the fluororesin particles to the total area of a second region in cross-section, in which the second region is located in a distance range of greater than or equal to 0.5 μm and less than 1.5 μm from the outermost surface of the surface layer to the substrate side;

A 3 represents the ratio (%) of the area of the fluororesin particles to the total area of a third region in cross-section, in which the third region is located in a distance range of 1.5 μm to (the thickness of the surface layer-0.5 μm) from the outermost surface of the surface layer to the substrate side; and

A 4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.

2. The electrophotographic photoreceptor according to claim 1 ,

wherein the surface layer contains a cross-linked component, and

the cross-linked component is a reaction product of a cross-linking compound having an alkoxy group and a cross-linking compound having a hydroxyl group.

3. The electrophotographic photoreceptor according to claim 2 ,

wherein the cross-linking compound having an alkoxy group is a compound having two or more alkoxy groups, and

the cross-linking compound having a hydroxyl group is a compound having two or more hydroxyl groups.

4. The electrophotographic photoreceptor according to claim 1 ,

wherein the thickness of the surface layer is from 3 μm to 15 μm.

5. The electrophotographic photoreceptor according to claim 1 ,

wherein the thickness of the surface layer is from 6 μm to 10 μm.

6. The electrophotographic photoreceptor according to claim 1 ,

wherein a content of the fluororesin particles is from 1% by weight to 30% by weight.

7. The electrophotographic photoreceptor according to claim 1 ,

wherein an average primary particle size of the fluororesin particles is from 0.05 μm to 1 μm.

8. The electrophotographic photoreceptor according to claim 1 ,

wherein the fluororesin is selected from a group consisting of polytetrafluoroethylene, polychlorotrifluoroethylene, polyhexafluoropropylene, polyvinyl fluoride, polyvinylidene fluoride, and polydichlorodifluoroethylene.

9. The electrophotographic photoreceptor according to claim 1 ,

wherein the surface layer satisfies the following expressions:

0 ≦A 1 ≦0.1 ×A 4   Expression (4)

0.3 ×A 4 <A 2 ≦0.5 ×A 4   Expression (5)

0.9 ×A 4 <A 3   Expression (6)

wherein,

A 1 represents the ratio (%) of the area of the fluororesin particles to the total area of a first region in cross-section, in which the first region is located in a distance range of greater than or equal to 0.2 μm and less than 0.5 μm from the outermost surface of the surface layer to the substrate side;

A 2 represents the ratio (%) of the area of the fluororesin particles to the total area of a second region in cross-section, in which the second region is located in a distance range of greater than or equal to 0.5 μm and less than 1.5 μm from the outermost surface of the surface layer to the substrate side;

A 3 represents the ratio (%) of the area of the fluororesin particles to the total area of a third region in cross-section, in which the third region is located in a distance range of 1.5 μm to (the thickness of the surface layer-0.5 μm) from the outermost surface of the surface layer to the substrate side; and

A 4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.

10. The electrophotographic photoreceptor according to claim 1 , wherein the surface layer further contains a copolymer having an alkyl fluoride group.

11. A process cartridge comprising:

an electrophotographic photoreceptor; and

at least one unit selected from a charging unit (A) that charges a surface of the electrophotographic photoreceptor; a latent image forming unit (B) that forms an electrostatic latent image on a charged surface of the electrophotographic photoreceptor; a developing unit (C) that develops the electrostatic latent image formed on the surface of the electrophotographic photoreceptor by using a toner to form a toner image; a transfer unit (D) that transfers the toner image, which is formed on the surface of the electrophotographic photoreceptor, onto a recording medium; and a cleaning unit (E) that cleans the electrophotographic photoreceptor,

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

12. The process cartridge according to claim 11 ,

wherein a surface layer of the electrophotographic photoreceptor includes a cross-linked component, and

the cross-linked component is a reaction product of a cross-linking compound having an alkoxy group and a cross-linking compound having a hydroxyl group.

13. The process cartridge according to claim 11 ,

wherein a surface layer of the electrophotographic photoreceptor satisfies the following expressions:

0 ≦A 1 ≦0.1 ×A 4   Expression (4)

0.3 ×A 4 <A 2 ≦0.5 ×A 4   Expression (5)

0.9 ×A 4 <A 3   Expression (6)

wherein,

A 1 represents the ratio (%) of the area of the fluororesin particles to the total area of a first region in cross-section, in which the first region is located in a distance range of greater than or equal to 0.2 μm and less than 0.5 μm from the outermost surface of the surface layer to the substrate side;

A 2 represents the ratio (%) of the area of the fluororesin particles to the total area of a second region in cross-section, in which the second region is located in a distance range of greater than or equal to 0.5 μm and less than 1.5 μm from the outermost surface of the surface layer to the substrate side;

A 3 represents the ratio (%) of the area of the fluororesin particles to the total area of a third region in cross-section, in which the third region is located in a distance range of 1.5 μm to (the thickness of the surface layer-0.5 μm) from the outermost surface of the surface layer to the substrate side; and

A 4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.

14. An image forming apparatus comprising:

an electrophotographic photoreceptor;

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 formed on the surface of the electrophotographic photoreceptor by 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,

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

15. The image forming apparatus according to claim 14 ,

wherein a surface layer of the electrophotographic photoreceptor contains a cross-linked component, and

the cross-linked component is a reaction product of a cross-linking compound having an alkoxy group and a cross-linking compound having a hydroxyl group.

16. The image forming apparatus according to claim 14 ,

wherein a surface layer of the electrophotographic photoreceptor satisfies the following expressions:

0 ≦A 1 ≦0.1 ×A 4   Expression (4)

0.3 ×A 4 <A 2 ≦0.5 ×A 4   Expression (5)

0.9 ×A 4 <A 3   Expression (6)

wherein,

A 1 represents the ratio (%) of the area of the fluororesin particles to the total area of a first region in cross-section, in which the first region is located in a distance range of greater than or equal to 0.2 μm and less than 0.5 μm from the outermost surface of the surface layer to the substrate side;

A 2 represents the ratio (%) of the area of the fluororesin particles to the total area of a second region in cross-section, in which the second region is located in a distance range of greater than or equal to 0.5 μm and less than 1.5 μm from the outermost surface of the surface layer to the substrate side;

A 3 represents the ratio (%) of the area of the fluororesin particles to the total area of a third region in cross-section, in which the third region is located in a distance range of 1.5 μm to (the thickness of the surface layer-0.5 μm) from the outermost surface of the surface layer to the substrate side; and

A 4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.