# US 8,465,890 B2 · Electrophotographic photoconductor and image forming apparatus including the same, and coating solution for undercoat layer formation in electrophotographic photoconductor

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

- Number: US 8,465,890 B2
- Document ID: US8465890B2
- Status: Granted
- Kind: B2
- Application number: 13/218,806
- Filed: 2011-08-26
- Published: 2012-03-01
- Granted: 2013-06-18
- Earliest claimed: 2010-08-30
- Assignees: Sharp Kabushiki Kaisha
- Applicants: Satoshi Katayama
- Inventors: Satoshi Katayama
- Web page: https://patentgrep.com/patent/US8465890B2

## CPC

- G03G 5/142: {Inert intermediate layers}
- C09D 177/00: Coating compositions based on polyamides obtained by reactions forming a carboxylic amide link in the main chain (based on polyhydrazides C09D179/06; based on polyamide-imides C09D179/08); Coating compositions based on derivatives of such polymers
- G03G 5/0525: {Coating methods}
- G03G 5/0696: {Phthalocyanines}
- G03G 5/144: {comprising inorganic material}
- G03G 2215/00957: Compositions
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)

## Abstract

An electrophotographic photoconductor comprising a conductive support, an undercoat layer and a photosensitive layer, the undercoat layer and the photosensitive layer being formed on the conductive support in sequence, wherein the undercoat layer contains a binder resin, titanium oxide particles surface-treated with at least anhydrous silicon dioxide and titanium oxide particles surface-treated with at least hydrous silicon dioxide.

## Claims

### Claim 1

An electrophotographic photoconductor comprising a conductive support, an undercoat layer and a photosensitive layer, the undercoat layer and the photosensitive layer being formed on the conductive support in sequence, wherein the undercoat layer contains a binder resin, titanium oxide particles surface-treated with at least anhydrous silicon dioxide and titanium oxide particles surface-treated with at least hydrous silicon dioxide.

### Claim 2 (depends on 1)

The photoconductor according to claim 1, wherein the titanium oxide particles surface-treated with anhydrous silicon dioxide and the titanium oxide particles surface-treated with hydrous silicon dioxide are contained at a ratio by weight of 80/20 to 30/70.

### Claim 3 (depends on 1)

The photoconductor according to claim 1, wherein the titanium oxide particles surface-treated with hydrous silicon dioxide are titanium oxide particles surface-treated with hydrous silicon dioxide and aluminum hydroxide.

### Claim 4 (depends on 1)

The photoconductor according to claim 1, wherein the titanium oxide particles surface-treated with hydrous silicon dioxide are those surface-treated with a mixture of hydrous silicon dioxide and aluminum hydroxide mixed at a ratio by weight of 10/90 to 90/10.

### Claim 5 (depends on 1)

The photoconductor according to claim 1, wherein the photosensitive layer contains a phthalocyanine as a charge generation material.

### Claim 6 (depends on 1)

The photoconductor according to claim 1, wherein the photosensitive layer contains, as a charge generation material, a phthalocyanine selected from a τ type metal-free phthalocyanine; a titanylphthalocyanine of a crystal type having a maximum diffraction peak in an X-ray diffraction spectrum at a Bragg angle (2θ±0.2°) of 27.3° and a titanylphthalocyanine of a crystal type at least having diffraction peaks in an X-ray diffraction spectrum at Bragg angles (2θ±0.2°) of 7.3°, 9.4°, 9.7° and 27.3°, among which the diffraction peaks at 9.4° and 9.7° are both clear branch peaks and greater than the diffraction peak at 27.3°, and the diffraction peak at 9.4° is a maximum diffraction peak.

### Claim 7 (depends on 1)

The photoconductor according to claim 1, wherein the titanium oxide particles have an average primary particle diameter of 20 nm to 100 nm.

### Claim 8 (depends on 1)

The photoconductor according to claim 1, wherein the titanium oxide particles are contained in the undercoat layer at a ratio by weight of 10/90 to 95/5 with respect to the binder resin.

### Claim 9 (depends on 1)

The photoconductor according to claim 1, wherein the binder resin is a polyamide resin.

### Claim 10 (depends on 1)

The photoconductor according to claim 1, wherein the undercoat layer has a film thickness of 0.05 μm to 5 μm.

### Claim 11 (depends on 1)

The photoconductor according to claim 1, wherein the photosensitive layer is a multilayer photosensitive layer comprising a charge generation layer and a charge transfer layer, the charge generation layer having a film thickness of 0.05 μm to 5 μm.

### Claim 12 (depends on 1)

An image forming apparatus including the electrographic photoconductor according to claim 1.

### Claim 13 (depends on 12)

An image forming method comprising using the image forming apparatus according to claim 12.