# US 2013/0252151 A1 · Electrophotographic photoreceptor, image forming apparatus, and process cartridge

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- Number: US 2013/0252151 A1
- Document ID: US20130252151A1
- Status: Published application
- Kind: A1
- Application number: 13/624,512
- Filed: 2012-09-21
- Published: 2013-09-26
- Earliest claimed: 2012-03-26
- Assignees: Fuji Xerox Co., Ltd.
- Applicants: Fuji Xerox Co., Ltd.
- Inventors: Shinya YAMAMOTO
- Web page: https://patentgrep.com/patent/US20130252151A1

## CPC

- G03G 5/147: Cover layers
- G03G 5/0592: {Macromolecular compounds characterised by their structure or by their chemical properties, e.g. block polymers, reticulated polymers, molecular weight, acidity}
- G03G 5/14708: {comprising organic material}
- G03G 5/1476: {Other polycondensates comprising oxygen atoms in the main chain; Phenol resins}
- G03G 5/14769: {Other polycondensates comprising nitrogen atoms with or without oxygen atoms in the main chain}
- G03G 5/14791: {Macromolecular compounds characterised by their structure, e.g. block polymers, reticulated polymers, or by their chemical properties, e.g. by molecular weight or acidity}
- G03G 5/14795: {Macromolecular compounds characterised by their physical properties}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An electrophotographic photoreceptor includes 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 specific expressions.

## Claims

### Claim 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≦A1≦0.2×A4 Expression (1)
0.2×A4<A2≦0.6×A4 Expression (2)
0.6×A4<A3 Expression (3)
wherein,
A1 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;
A2 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;
A3 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
A4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 2)

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.

### Claim 4 (depends on 1)

The electrophotographic photoreceptor according to claim 1,
wherein the thickness of the surface layer is from 3 μm to 15 μm.

### Claim 5 (depends on 1)

The electrophotographic photoreceptor according to claim 1,
wherein the thickness of the surface layer is from 6 μm to 10 μm.

### Claim 6 (depends on 1)

The electrophotographic photoreceptor according to claim 1,
wherein a content of the fluororesin particles is from 1% by weight to 30% by weight.

### Claim 7 (depends on 1)

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.

### Claim 8 (depends on 1)

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.

### Claim 9 (depends on 1)

The electrophotographic photoreceptor according to claim 1,
wherein the surface layer satisfies the following expressions:
0≦A1≦0.1×A4 Expression (4)
0.3×A4<A2≦0.5×A4 Expression (5)
0.9×A4<A3 Expression (6)
wherein,
A1 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;
A2 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;
A3 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
A4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.

### Claim 10 (depends on 1)

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

### Claim 11 (depends on 1)

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.

### Claim 12 (depends on 11)

The image forming apparatus according to claim 11,
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.

### Claim 13 (depends on 11)

The image forming apparatus according to claim 11,
wherein a surface layer of the electrophotographic photoreceptor satisfies the following expressions:
0≦A1≦0.1×A4 Expression (4)
0.3×A4<A2≦0.5×A4 Expression (5)
0.9×A4<A3 Expression (6)
wherein,
A1 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;
A2 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;
A3 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
A4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.

### Claim 14 (depends on 1)

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.

### Claim 15 (depends on 14)

The process cartridge according to claim 14,
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.

### Claim 16 (depends on 14)

The process cartridge according to claim 14,
wherein a surface layer of the electrophotographic photoreceptor satisfies the following expressions:
0≦A1≦0.1×A4 Expression (4)
0.3×A4<A2≦0.5×A4 Expression (5)
0.9×A4<A3 Expression (6)
wherein,
A1 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;
A2 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;
A3 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
A4 represents the ratio (%) of the area of the fluororesin particles to the total area of the cross-section.