Optical writing apparatus, image forming apparatus, and control method

Patent metadata

Field	Value
Publication number	US-11964496-B2
Application number	US-202217685564-A
Country	US
Kind code	B2
Filing date	Mar 3, 2022
Priority date	Mar 30, 2021
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

An optical writing device, and a method of controlling the optical writing device. The optical writing device and the method includes controlling speed of operation of a light deflector based on image magnifying-power information in a sub-scanning direction parallel to a direction in which a surface of a photoconductor moves, and controlling a prescribed write clock frequency such that a number of clock pulses of write light will become a target number of pulses over a period where the write light scans an area within a prescribed distance in a main scanning direction, the target number of pulses being maintained even when the speed of operation of the light deflector is changed in the controlling the speed of operation of the light deflector. The write clock frequency controller maintains the target number of pulses even when the speed of operation of the light deflector is changed by the light-deflector controller.

First claim

What is claimed is:

1. An optical writing device comprising:
a light source configured to emit light at a prescribed write clock frequency, the light emitted from the light source indicating image data;
a light deflector configured to deflect write light including repetition pulsed light corresponding to the image data to scan a moving surface of a photoconductor repeatedly in a main scanning direction, and to write a latent image on the surface of the photoconductor based on the image data;
a light-deflector controller configured to control speed of operation of the light deflector based on image magnifying-power information in a sub-scanning direction parallel to a direction in which the surface of the photoconductor moves; and
a write clock frequency controller configured to control the prescribed write clock frequency such that a number of clock pulses of the write light will become a target number of pulses over a period where the write light scans an area within a prescribed distance in the main scanning direction, the write clock frequency controller being configured to maintain the target number of pulses even when the speed of operation of the light deflector is changed by the light-deflector controller.

2. The optical writing device according to claim 1 ,
wherein the write clock frequency controller is configured by a feedback control circuit to which an electrical signal relating to the period is input, and
wherein the feedback control circuit is configured to output an electrical signal relating to the prescribed write clock frequency at which the number of clock pulses of the write light in the period is set to the target number of pulses.

3. The optical writing device according to claim 1 ,
wherein the write clock frequency controller comprises a counter configured to count a number of the clock pulses of the write light during the period, to control the prescribed write clock frequency, and
wherein the number of the clock pulses counted by the counter becomes equivalent to the target number of pulses as the prescribed write clock frequency is controlled by the write clock frequency controller.

4. The optical writing device according to claim 1 , further comprising
a light receiver disposed in an optical scanning range of the write light deflected by the light deflector,
wherein the period is a period between an instant when the light receiver receives the write light and an instant when the light receiver receives the write light next time or after the next time.

5. The optical writing device according to claim 1 , further comprising
a pair of light receivers disposed in an optical scanning range of the write light deflected by the light deflector,
wherein the period is a period between an instant when one of the pair of light receivers receives the write light and an instant when another one of the pair of light receivers receives the write light.

6. The optical writing device according to claim 1 ,
wherein, when the speed of operation of the light deflector is controlled based on the image magnifying-power information in the sub-scanning direction, the light-deflector controller is configured to maintain the speed of operation of the light deflector at a constant degree during a latent-image writing period, and to change the speed of operation of the light deflector during a period in which no latent image is written.

7. The optical writing device according to claim 1 ,
wherein, when the prescribed write clock frequency is controlled, the write clock frequency controller is configured to maintain the prescribed write clock frequency at a constant degree during a latent-image writing period, and to change the prescribed write clock frequency during a period in which no latent image is written.

8. An image forming apparatus comprising:
a photoconductor; and
the optical writing device according to claim 1 configured to write a latent image on a surface of the photoconductor based on image data.

9. A method of controlling an optical writing device, the method comprising:
controlling speed of operation of a light deflector based on image magnifying-power information in a sub-scanning direction parallel to a direction in which a surface of a photoconductor moves; and
controlling a prescribed write clock frequency such that a number of clock pulses of write light will become a target number of pulses over a period where the write light scans an area within a prescribed distance in a main scanning direction, the target number of pulses being maintained even when the speed of operation of the light deflector is changed in the controlling the speed of operation of the light deflector.

Assignees

• Matsuura Yuugo
• Ricoh Co Ltd

Inventors

• Matsuura Yuugo

Classifications

• B41J2/471 Primary

  using dot sequential main scanning by means of a light deflector, e.g. a rotating polygonal mirror · CPC title

• B41J2/47

  using the combination of scanning and modulation of light · CPC title

• G02B26/124

  Details of the optical system between the light source and the polygonal mirror (G02B26/123, G02B26/127 take precedence) · CPC title

• G03G15/0415

  and means for controlling illumination or exposure · CPC title

• B41J2/435

  characterised by selective application of radiation to a printing material or impression-transfer material · CPC title