OPTICAL SCANNING DEVICE AND IMAGE FORMING APPARATUS

• US 20080055672A1
• Filed: 08/27/2007
• Published: 03/06/2008
• Est. Priority Date: 09/04/2006
• Status: Abandoned Application

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Ichii, Daisuke, Sato, Shunichi, WATANABE, Naoto
• Application Number:
  US11/845,409
• Publication Number:
  US 20080055672A1
• Time in Patent Office: Days
• US Class Current: 358/474
• 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 2215/0404 Laser
• 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 1/195 the array comprising a two-dimensional array or a combination of two-dimensional arrays
• CPC Class Codes: H04N 2201/0082 Image hardcopy reproducer H04N2201/0091 - H04N2201/0094 take precedence
• CPC Class Codes: H04N 2201/0446 Constructional details not otherwise provided for, e.g. mounting of scanning components H04N2201/0448 takes precedence

Abstract

A two-dimensional array include N light-emitting arrays each formed of M light-emitting units arranged equally spaced along a direction T tilting from a main scanning direction at an angle α toward a sub-scanning direction. The light-emitting arrays are equally spaced in the sub-scanning direction. A space ds2 between light-emitting arrays with respect to the sub-scanning direction satisfies ds2=ds1×M where ds1 is a positional difference in the sub-scanning direction between light-emitting units which are adjacent each other in the main scanning direction and orthographically-projected on a virtual line extending in the sub-scanning direction. The angle α satisfies α=sin⁻¹((ds2/d1)/M) where d1 is a space between light-emitting units in the light-emitting array with respect to the direction T. The space ds2 is equal to the space d1.

Claims

1. An optical scanning device comprising:

a light source that includes a two-dimensional array of light-emitting units; and

an optical system that scans a target surface with light beams from the light source, wherein

the two-dimensional array include N light-emitting arrays each formed of M light-emitting units arranged equally spaced along a first direction, the first direction tilting from a main scanning direction at an angle α

toward a sub-scanning direction,

the light-emitting arrays are equally spaced in the sub-scanning direction,

a space ds2 between adjacent light-emitting arrays with respect to the sub-scanning direction satisfies ds2=ds1×

M where ds1 is a positional difference in the sub-scanning direction between light-emitting units adjacent each other in the main scanning direction in the light-emitting array orthographically-projected on a virtual line extending in the sub-scanning direction, and

the angle α

satisfies α

=sin<sup>−

1</sup>((ds2/d1)/M) where d1 is a space between adjacent light-emitting units in the light-emitting array with respect to the first direction.

2. The optical scanning device according to claim 1, wherein 1.0≧

ds2/d1≧

0.5 is satisfied.

3. The optical scanning device according to claim 1, wherein N<

M is satisfied.

4. The optical scanning device according to claim 1, wherein ds1 is not less than 1 micrometer and not more than 4 micrometers.

5. The optical scanning device according to claim 1, wherein the light-emitting arrays are vertical-cavity surface-emitting laser arrays.

12. An image forming apparatus comprising:

an image carrier;

the optical scanning device according to claim 1 that scans the image carrier with the light beams corresponding to image information; and

a transfer device that transfers an image formed on the image carrier onto a transfer medium.

6. An optical scanning device comprising:

a light source that includes a two-dimensional array of light-emitting units; and

an optical system that scans a target surface with light beams from the light source, wherein

the two-dimensional array include N light-emitting arrays each formed of M light-emitting units arranged equally spaced along a first direction, the first direction tilting from a main scanning direction at an angle α

toward a sub-scanning direction,

the light-emitting arrays are equally spaced in the sub-scanning direction, and alternately extend in the first direction from a first position and a second position,

a space ds2 between adjacent light-emitting arrays with respect to the sub-scanning direction satisfies ds2=ds1×

M where ds1 is a positional difference in the sub-scanning direction between light-emitting units adjacent each other in the main scanning direction in the light-emitting array orthographically-projected on a virtual line extending in the sub-scanning direction, and

the angle α

satisfies α

=sin<sup>−

1</sup>((ds2/d1)/M) where d1 is a space between adjacent light-emitting units in the light-emitting array with respect to the first direction.

7. The optical scanning device according to claim 6, wherein a space between the first position and the second position with respect to the main scanning direction is one half of a space between adjacent light-emitting units in the light-emitting array orthographically-projected on a virtual line extending in the main scanning direction.

8. The optical scanning device according to claim 6, wherein ds2/d1≦

0.5 is satisfied.

9. The optical scanning device according to claim 6, wherein N<

M is satisfied.

10. The optical scanning device according to claim 6, wherein ds1 is not less than 1 micrometer and not more than 4 micrometers.

11. The optical scanning device according to claim 6, wherein the light-emitting arrays are vertical-cavity surface-emitting laser arrays.

13. An image forming apparatus comprising:

an image carrier;

the optical scanning device according to claim 6 that scans the image carrier with the light beams corresponding to image information; and

a transfer device that transfers an image formed on the image carrier onto a transfer medium.