| US 7,551,192 B2 | ||
| Optical-beam scanning apparatus and image forming apparatus | ||
| Nobuyoshi Kaima, Tokyo (Japan) | ||
| Assigned to Ricoh Company, Ltd., Tokyo (Japan) | ||
| Filed on Jan. 17, 2006, as Appl. No. 11/332,207. | ||
| Claims priority of application No. 2005-014547 (JP), filed on Jan. 21, 2005. | ||
| Prior Publication US 2006/0164661 A1, Jul. 27, 2006 | ||
| Int. Cl. B41J 2/47 (2006.01); B41J 2/435 (2006.01); G03G 15/01 (2006.01); G06K 15/02 (2006.01) | ||
| U.S. Cl. 347—235 [347/246; 347/250; 399/301; 358/1.2] | 7 Claims |
| 1. An optical beam scanning apparatus comprising:
a light source configured to emit an optical beam;
a control unit configured to control the light source to emit the optical beam according to image data;
a deflecting unit configured to deflect the optical beam in a main scanning direction;
a detecting unit configured to detect deflected optical beam on a main scanning line;
a first correcting unit configured to correct a main scanning magnification; and
a second correcting unit configured to correct the main scanning magnification, wherein, when an error is not detected in
a count value based on a scanning time of the optical beam,
the first correcting unit includes a clock generator configured to generate a lighting control clock for the light source
based on the count value,
the second correcting unit includes a clock-phase changing unit configured to change a phase of the lighting control clock
by a unit of 1/n, where n is a positive integer equal to or larger than two, and
the main scanning magnification is corrected by a combination of correction by the first correcting unit and correction by
the second correcting unit.
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