# US 2010/0166444 A1 · Image forming apparatus and image forming method

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- Number: US 2010/0166444 A1
- Document ID: US20100166444A1
- Status: Published application
- Kind: A1
- Application number: 12/642,654
- Filed: 2009-12-18
- Published: 2010-07-01
- Earliest claimed: 2008-12-26
- Assignees: Seiko Epson Corporation
- Inventors: Yujiro NOMURA; Ken IKUMA
- Web page: https://patentgrep.com/patent/US20100166444A1

## CPC

- G03G 15/043: with means for controlling illumination or exposure (G03G15/041 takes precedence)
- B41J 2/451: {Special optical means therefor, e.g. lenses, mirrors, focusing means}
- G03G 21/145: {wherein control pulses are generated by the mechanical movement of parts of the machine, e.g. the photoconductor}
- G03G 2215/0409: Light-emitting diodes, i.e. LED-array
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS

## Abstract

An image forming apparatus includes: a latent image carrier which carries a latent image; an exposure head which exposes the latent image carrier to light emitted from a light emitting element; a driver which rotationally drives the latent image carrier; a light emission controller which controls light emission time of the light emitting element; a rotational angle detector which detects a rotational angle of the latent image carrier; and a memory which stores first light emission time correction information to correct the light emission time in response to an eccentricity of the latent image carrier. The light emission controller permits the light emitting element to emit light at the light emission time corrected on the basis of a detection result of the rotational angle detector and the first light emission time correction information.

## Claims

### Claim 1

An image forming apparatus comprising:
a latent image carrier that carries a latent image;
an exposure head that forms a latent image to emit light from a light emitting element;
a driver that rotationally drives the latent image carrier;
a light emission controller that controls light emission time of the light emitting element;
a rotational angle detector that detects a rotational angle of the latent image carrier; and
a memory that stores first light emission time correction information to correct the light emission time in response to an eccentricity of the latent image carrier,
wherein the light emission controller permits the light emitting element to emit light at the light emission time corrected on the basis of a detection result of the rotational angle detector and the first light emission time correction information.

### Claim 2 (depends on 1)

The image forming apparatus according to claim 1, wherein the light emission controller obtains second light emission correction information to correct the light emission time from the detection result of the rotational angle detector in response to a variation in the angular velocity of the latent image carrier, and corrects the light emission time on the basis of the first light emission time correction information and the second light emission time correction information.

### Claim 3 (depends on 1)

The image forming apparatus according to claim 1, wherein the latent image carrier is a photoconductive drum having a rotational shaft, and the driver rotationally drives the rotational shaft.

### Claim 4 (depends on 3)

The image forming apparatus according to claim 3, wherein the rotational angle detector is an encoder disposed on the rotational shaft of the photoconductive drum.

### Claim 5 (depends on 3)

The image forming apparatus according to claim 3, wherein the memory is disposed in a cartridge that is detachably mounted in the image forming apparatus and holds the photoconductive drum.

### Claim 6 (depends on 5)

The image forming apparatus according to claim 5, wherein the memory is a non-volatile memory.

### Claim 7

An image forming method comprising:
detecting a rotation angle of a latent image carrier that is rotationally driven; and
forming a latent image to emit light from a light emitting element,
wherein the exposing includes reading from a memory first light emission time correction information to correct light emission time in response to an eccentricity of the latent image carrier, and permitting the light emitting element to emit light at the light emission time corrected on the basis of a detection result from the detecting of the rotation angle and the first light emission time correction information.