OPTICAL SCANNING DEVICE AND IMAGE FORMING APPARATUS

• US 20080267663A1
• Filed: 04/28/2008
• Published: 10/30/2008
• Est. Priority Date: 04/26/2007
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Ishida, Masaaki, Hayashi, Yoshinori, Hirakawa, Makoto, Suzuki, Seizo, ICHII, Daisuke
• Granted Patent: US 7,903,135 B2
• Time in Patent Office: Days
• US Class Current: 399/177
• CPC Class Codes: B41J 2/473 using multiple light beams, wavelengths or colours
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters
• CPC Class Codes: G03G 15/043 with means for controlling illumination or exposure G03G15/041 takes precedence
• CPC Class Codes: G03G 15/0435 by introducing an optical element in the optical path, e.g. a filter
• CPC Class Codes: G03G 15/326 by application of light, e.g. using a LED array
• CPC Class Codes: G03G 2215/0407 Light-emitting array or panel
• CPC Class Codes: H04N 1/1135 for the main-scan only
• CPC Class Codes: H04N 1/12 using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanningsheet-feed movement by translatory movement of a flat picture-bearing surface H04N1/1008; main-scanning using oscillating or rotating mirrors H04N1/113; using multi-element arrays H04N1/19
• CPC Class Codes: H04N 1/1912 Scanning main scanning lines which are spaced apart from one another in the sub-scanning direction
• CPC Class Codes: H04N 1/1917 Staggered element array, e.g. arrays with elements arranged in a zigzag
• CPC Class Codes: H04N 2201/0082 Image hardcopy reproducer H04N2201/0091 - H04N2201/0094 take precedence

Abstract

An optical scanning device which scans a scanned surface by a plurality of light beams in a main-scanning direction includes a light source having a plurality of light-emitting portions which emit the light beams, the light-emitting portions being two-dimensionally arranged in a plane parallel to the main-scanning direction and a sub-scanning direction orthogonal to the main-scanning direction via arrangement intervals in the main-scanning direction and the sub-scanning direction, a deflector which scans the light beams in the main-scanning direction; and a scanning optical system which images the scanned light beams onto the scanned surface.

Claims

1. An optical scanning device which scans a scanned surface by a plurality of light beams in a main-scanning direction;

comprising;

a light source having a plurality of light-emitting portions which emit the light beams, the light-emitting portions being two-dimensionally arranged in a plane parallel to the main-scanning direction and a sub-scanning direction orthogonal to the main-scanning direction via arrangement intervals in the main-scanning direction and the sub-scanning direction;

a deflector which scans the light beams in the main-scanning direction; and

a scanning optical system which images the scanned light beams onto the scanned surface.

2. An optical scanning device according to claim 1, wherein the arrangement intervals in the sub-scanning direction are an integral multiplication of a size of one light-emitting portion in the sub-scanning direction.

3. An optical scanning device according to claim 1, wherein scanning lines formed on the scanned surface with one scanning are formed via intervals according to the arrangement intervals, and scanning lines adjacent to the scanning lines in the sub-scanning direction are formed by multiple scanning.

4. An optical scanning device according to claim 1, wherein the arrangement intervals in the main-scanning direction and the arrangement intervals in the sub-scanning direction are unequal.

5. An optical scanning device according to claim 4, wherein the arrangement interval of a central portion of the light source in the main-scanning direction is larger than the arrangement interval of both end portions of the light source in the main-scanning direction, and the arrangement interval of the central portion of the light source in the sub-scanning direction is larger than the arrangement interval of the both end portions of the light source in the sub-scanning direction.

6. An optical scanning device according to claim 4, wherein the arrangement intervals become smaller toward both end portions of the main-scanning direction from a central portion of the light source, and become smaller toward both end portions of the sub-scanning direction from the central portion.

7. An optical scanning device according to claim 4, wherein the arrangement intervals become smaller toward both end portions of the main-scanning direction from a central portion of the light source.

8. An optical scanning device according to claim 4, wherein the arrangement intervals become smaller toward both end portions of the sub-scanning direction from a central portion of the light source.

9. An optical scanning device according to claim 4, further comprising plural pairs of light-emitting portions in which the arrangement interval in the main-scanning direction is the largest, wherein out of the plural pairs of light-emitting portions, at least the arrangement interval of the pair of light-emitting portions located in furthermost positions in the sub-scanning direction from a central portion of the light source is the smallest in the arrangement intervals of the plural pairs of light-emitting portions in the sub-scanning direction.

10. An optical scanning device according to claim 1, wherein the light-emitting portions located in both ends in the sub-scanning direction are arranged in positions nearest to a central portion of the light source in the main-scanning direction.

11. An optical scanning device according to claim 1, wherein the plurality of light-emitting portions includes the light-emitting portions in which the positions in the main-scanning direction are the same.

12. An optical scanning device according to claim 1, wherein the arrangement intervals in the sub-scanning directions are unequal.

13. An optical scanning device according to claim 1, wherein the arrangement intervals of the light-emitting portions in the sub-scanning direction, which are adjacently arranged in a central portion of the sub-scanning direction, are larger than the arrangement intervals of the light source in the sub-scanning direction, which are adjacently arranged in other portions of the sub-scanning direction.

14. An optical scanning device according to claim 3, wherein the plurality of the light-emitting portions is arranged in different positions in the sub-scanning direction, and where the number of the light-emitting portions is k, the intervals of the sub-scanning direction of the scanning lines located in both ends of the sub-scanning direction, which are formed on the scanned surface with one scanning, are L1, and the intervals of the sub-scanning direction of the scanning lines adjacent in the sub-scanning direction, which are formed on the scanned face by multiple scanning, are L2, L1, k, and L2 satisfy L1>

(k−

1)×

L2.

15. An optical scanning device according to claim 14, wherein L1, k, and L2 satisfy 2k×

L2≦

L1≦

3k×

L2.

16. An optical scanning device according to claim 1, further comprising a light guide optical system having a first optical system which couples the light beams emitted from the light-emitting portions, a second optical system which concentrates the coupled light beams in the sub-scanning direction near a deflection face of the deflector, and the scanning optical system, wherein an absolute value of a lateral magnification of the main-scanning direction of the light guide optical system is larger than an absolute value of a lateral magnification of the sub-scanning direction.

17. An optical scanning device according to claim 16, wherein the second optical system includes an optical element which advances a pair of light beams emitted from the light-emitting portions located at furthermost positions in the sub-scanning direction to be parallel or to approach each other after passing through the second optical system.

18. An optical scanning device according to claim 17, further comprising an intermediate member, which retains at least one end of the main-scanning direction of the optical system and is attached to an optical housing which retains the second optical system.

19. An optical scanning device according to claim 1, wherein the light beam has a beam diameter in the main-scanning direction larger than a beam diameter in the sub-scanning direction.

20. An image forming apparatus, which fixes a toner image formed according to an electrostatic latent image obtained from information regarding an image onto a recording medium, comprising:

an optical scanning device according to claim 1,

a photoconductive body having the scanned face on which the electrostatic latent image is formed by the optical scanning device;

a development unit which visualizes the electrostatic latent image formed on the scanned face of the photoconductor as the toner image; and

a transfer unit which fixes the toner image visualized by the development unit onto the recording medium.