# US 8,568,945 B2 · Electrophotographic photoreceptor, and image forming apparatus and process cartridge therefor using the photoreceptor

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,568,945 B2
- Document ID: US8568945B2
- Status: Granted
- Kind: B2
- Application number: 12/625,746
- Filed: 2009-11-25
- Published: 2010-05-27
- Granted: 2013-10-29
- Earliest claimed: 2008-11-26
- Assignees: Ricoh Company, Ltd.
- Applicants: Hiromi Tada; Naohiro Toda; Yuuji Tanaka; Norio Nagayama; Yoshinori Inaba; Takafumi Iwamoto
- Inventors: Hiromi Tada; Naohiro Toda; Yuuji Tanaka; Norio Nagayama; Yoshinori Inaba; Takafumi Iwamoto
- Web page: https://patentgrep.com/patent/US8568945B2

## CPC

- G03G 5/0575: {Other polycondensates comprising nitrogen atoms with or without oxygen atoms in the main chain}
- G03G 5/0542: {Polyvinylalcohol, polyallylalcohol; Derivatives thereof, e.g. polyvinylesters, polyvinylethers, polyvinylamines}
- G03G 5/0592: {Macromolecular compounds characterised by their structure or by their chemical properties, e.g. block polymers, reticulated polymers, molecular weight, acidity}
- G03G 5/0696: {Phthalocyanines}
- G03G 2215/00957: Compositions
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An electrophotographic photoreceptor, including a charge generation layer and a charge transport layer on an electroconductive substrate, wherein the charge generation layer includes titanylphthalocyanine and a binder resin which is a crosslinked material of a resin comprising a polyvinylbutyrat site having the following formula (1) and an isocyanate compound having the following formula (2): wherein R1 and R2 independently represent an alkyl group having 1 to 3 carbon atoms; k, l, m and n represent composition ratios and k+1 is from 0.60 to 0.80, wherein k or 1 may be 0, m is from 0.02 to 0.03, and n is from 0.20 to 0.40; wherein A represents a substituted or unsubstituted organic group having 2 to 4 valences; and O represents an integer of from 2 to 4.

## Claims

### Claim 1

An electrophotographic photoreceptor, comprising a charge generation layer over an electroconductive substrate, and a charge transport layer on the charge generation layer,
wherein the charge generation layer comprises titanylphthalocyanine and a binder resin which is a crosslinked material of a resin comprising a polyvinylbutyral site having the following formula (1) and an isocyanate compound having the following formula (4):
wherein R1 and R2 independently represent an alkyl group having 1 to 3 carbon atoms; k, l, m and n represent composition ratios and k+1 is from 0.60 to 0.80, wherein k or 1 may be 0, m is from 0.02 to 0.03, and n is from 0.20 to 0.40;
wherein A3 represents a substituted or an unsubstituted non-aromatic hydrocarbon group or an aryl group; Ar1 represents a substituted or an unsubstituted aromatic ring; R3 and R4 independently represent a divalent organic group having 1 to 3 carbon atoms when A3 is a non-aromatic hydrocarbon group and a single bond when A3 is an aryl group; and q represents an integer of from 2 to 4.

### Claim 2 (depends on 1)

The electrophotographic photoreceptor of claim 1, wherein n in the formula (1) is from 0.30 to 0.40.

### Claim 3 (depends on 1)

The electrophotographic photoreceptor of claim 1, further comprising:
an undercoat layer positioned between the electroconductive substrate and the charge generation layer.

### Claim 4 (depends on 1)

An image forming apparatus, comprising:
the electrophotographic photoreceptor according to claim 1;
a charger configured to charge the electrophotographic photoreceptor;
an irradiator configured to irradiate the electrophotographic photoreceptor to form an electrostatic latent image thereon;
an image developer configured to develop the electrostatic latent image with a developer comprising a toner to form a toner image on the electrophotographic photoreceptor; and
a transferer configured to transfer the toner image onto a transfer material.

### Claim 5 (depends on 4)

The image forming apparatus of claim 4, wherein the electrophotographic photoreceptor and at least one of the charger. the irradiator, the transferer and a cleaner are unified as a process cartridge.

### Claim 6 (depends on 1)

A process cartridge for image forming apparatus, comprising:
electrophotographic photoreceptor according to claim 1; and at least one of
a charger configured to charge the electrophotographic photoreceptor;
an irradiator configured to irradiate the electrophotographic photoreceptor to form an electrostatic latent image thereon;
an image developer configured to develop the electrostatic latent image with a developer comprising a toner to form a toner image on the electrophotographic photoreceptor; and
a cleaner configured to clean the toner remaining on the electrophotographic photoreceptor after the toner image is transferred therefrom.