Optical scanning device and image forming apparatus

• US 7,598,972 B2
• Filed: 08/01/2006
• Issued: 10/06/2009
• Est. Priority Date: 08/03/2005
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Tomita, Yasumasa
• Primary Examiner(s): PHAM, HAI CHI
• Application Number:
  US11/496,523
• Publication Number:
  US 20070030333A1
• Time in Patent Office: 1,162 Days
• Field of Search: 347/115, 347/231, 347/243, 347259-261, 347/244, 347/229, 347234-235, 347248-250
• US Class Current: 347/235
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters
• CPC Class Codes: G02B 26/127 Adaptive control of the scanning light beam, e.g. using the feedback from one or more detectors G02B27/0031 takes precedence
• CPC Class Codes: H04N 1/40037 the reproducing element being a laser
• CPC Class Codes: H04N 1/506 Reproducing the colour component signals picture-sequentially, e.g. with reproducing heads spaced apart from one another in the subscanning direction

Abstract

A deflecting unit deflects a light beam emitted by each of a plurality of light-beam emitting units independently to scan surfaces of different bodies to be scanned. Each of a plurality of light-receiving units receives the deflected light beam at a predetermined position in a direction of the deflection. An incident angle of the deflected light beam with respect to a scanning line extending in a direction of scanning on a light-receiving surface of the light-receiving unit is set to be identical for all of the light-receiving units.

Claims

1. An optical scanning device, comprising:

a plurality of light-beam emitting units each of which emitting a light beam;

a deflecting unit that deflects the light beam emitted by each of the light-beam emitting units independently to scan surfaces of different bodies to be scanned; and

a plurality of light-receiving units each receiving the plurality of deflected light beams at a predetermined position in a direction of the deflection,

wherein the plurality of deflected light beams are emitted from different light-beam emitting units and are incident on one light-receiving unit, an incident angle of the plurality of deflected light beams on a light-receiving surface of the one light-receiving unit is set to be identical in a scanning surface formed by the beam scanned by the deflection unit, each of the plurality of deflected light beams scans the surfaces of corresponding different bodies to be scanned, each of the plurality of deflected light beams is, in a main-scanning surface, incident into the light-receiving unit with an angle of 90 degrees and is incident on a same straight line, and the plurality of light beams are, in a sub-scanning surface, incident into the light-receiving unit parallel to each other.

2. The optical scanning device according to claim 1, wherein

the incident angle is set to be perpendicular to the scanning line on the light-receiving surface.

3. The optical scanning device according to claim 2, wherein

a focal length of each of the deflected light beams is set such that a beam spot size of each of the deflected light beams is same as a smallest beam spot size that can be obtained on a scanning line of each of the bodies to be scanned for all of the light-receiving units.

4. The optical scanning device according to claim 1, wherein

two or more light beams emitted from different light-beam emitting units are incident on one light-receiving unit.

5. The optical scanning device according to claim 4, wherein

incident angles of the two or more light beams are set to be perpendicular to a scanning-orthogonal line that is perpendicular to the scanning line on the light-receiving surface.

6. The optical scanning device according to claim 4, further comprising:

a condensing lens that condenses each of the two or more light beams received by the one light-receiving unit in a direction of a surface perpendicular to a scanning direction.

7. The optical scanning device according to claim 6, wherein

the condensing lens has a condensing capability in a direction in which plural incident light beams are arranged.

8. The optical scanning device according to claim 4, wherein

number of reflection mirrors through which the light beam is routed from the light-beam emitting unit to the light-receiving unit is same for all of the two or more light beams received by the one light-receiving unit.

9. An image forming apparatus comprising:

a plurality of photoconductors for forming a latent image;

an optical scanning device that optically scans the photoconductors independently, to form latent images on the photoconductors;

a developing unit that develops the latent images formed on the photoconductors independently; and

a transfer unit that transfers visible images obtained by developing the latent images on the photoconductors to a transfer medium in a superimposing manner, wherein

the optical scanning device includes;

a plurality of light-beam emitting units each of which emitting a light beam;

a deflecting unit that deflects the light beam emitted by each of the light-beam emitting units independently to scan surfaces of different bodies to be scanned; and

a plurality of light-receiving units each receiving the plurality of deflected light beams at a predetermined position in a direction of the deflection,

wherein the plurality of deflected light beams are emitted from different light-beam emitting units and are incident on one light-receiving unit, an incident angle of the plurality of deflected light beams on a light-receiving surface of the one light-receiving unit is set to be identical in a scanning surface formed by the beam scanned by the deflection unit, each of the plurality of deflected light beams scans the surfaces of corresponding different bodies to be scanned, each of the plurality of deflected light beams is, in a main-scanning surface, incident into the light-receiving unit with an angle of 90 degrees and is incident on a same straight line, and the plurality of light beams are, in a sub-scanning surface, incident into the light-receiving unit parallel to each other.