| US 7,589,756 B2 | ||
| Optical scanning device, image forming apparatus, optical scanning correcting method, and image forming method | ||
| Iwao Matsumae, Tokyo (Japan); Yoshinobu Sakaue, Tokyo (Japan); and Kazunori Bannai, Kanagawa (Japan) | ||
| Assigned to Ricoh Company, Limited, Tokyo (Japan) | ||
| Filed on Sep. 15, 2006, as Appl. No. 11/521,560. | ||
| Claims priority of application No. 2005-270093 (JP), filed on Sep. 16, 2005. | ||
| Prior Publication US 2007/0064087 A1, Mar. 22, 2007 | ||
| Int. Cl. B41J 15/14 (2006.01); B41J 2/435 (2006.01); B41J 27/00 (2006.01) | ||
| U.S. Cl. 347—241 [347/250; 347/256; 347/257; 347/258; 347/259; 347/260; 347/261] | 14 Claims |
| 1. An optical scanning device for an image forming apparatus that forms a color image by combining a plurality of single color
images formed on a plurality of photosensitive elements, the optical scanning device comprising:
a plurality of light sources each of which emits an optical beam;
a deflecting unit that deflects the optical beams from the light sources;
a plurality of optical elements provided for each of the optical beams, sequentially arranged between the deflecting unit
and the photosensitive elements, to guide the optical beams deflected by the deflecting unit to the photosensitive elements;
a pair of beam detecting units provided for each of the optical beams for detecting at least one of a position of the optical
beam in a sub scanning direction and a position of the optical beam in a main scanning direction, the pair of beam detecting
units including a first beam detecting unit and a second beam detecting unit; and
a color-misalignment correcting unit provided for each of the optical beams for changing an optical-beam irradiating position
on each of the corresponding photosensitive elements based on a result of detection by the corresponding pair of beam detecting
units, wherein
the pair of beam detecting units being,
arranged between the optical element that is closest to the corresponding photosensitive element and the corresponding photosensitive
element,
integrally fitted to a housing of the optical scanning device,
fixed between holding members that hold the optical scanning device and a dustproof glass through which the corresponding
optical beam is transmitted, and
arranged on a scanning line of the corresponding optical beam so that the corresponding optical beam outside an effective
image area enters the pair of beam detecting units, and
each first beam detecting unit being placed at a position on one of the holding members and each second beam detecting unit
being placed at a position on another of the holding members.
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