OPTICAL SCANNING APPARATUS AND IMAGE FORMING APPARATUS

• US 20080024849A1
• Filed: 07/20/2007
• Published: 01/31/2008
• Est. Priority Date: 07/24/2006
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Ichii, Daisuke, Hayashi, Yoshinori, Sato, Shunichi
• Granted Patent: US 7,800,805 B2
• Time in Patent Office: Days
• US Class Current: 359/204
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters
• CPC Class Codes: H01S 5/18311 using selective oxidation
• CPC Class Codes: H01S 5/18358 containing spacer layers to adjust the phase of the light wave in the cavity
• CPC Class Codes: H01S 5/3211 characterised by special cladding layers, e.g. details on band-discontinuities
• CPC Class Codes: H01S 5/3432 the whole junction comprising only (AI)GaAs
• CPC Class Codes: H01S 5/3434 with a well layer comprising at least both As and P as V-compounds
• CPC Class Codes: H01S 5/3436 based on InGa(Al)P
• CPC Class Codes: H01S 5/423 having a vertical cavity

Abstract

In an optical scanning apparatus, when it is assumed that a scanning direction of light beams defected from a deflector is a main scanning direction, and a direction orthogonal to the main scanning direction and to optical axes of both a first and a second optical systems is a sub scanning direction, a distance between the outermost light emitting diodes of a light source in the main scanning direction is longer than that in the sub scanning direction.

Claims

1. An optical scanning apparatus comprising:

a light source including a two-dimensional array of light emitting diodes, each light emitting diode configured to emit a light beam;

a first optical system that leads the light beams emitted from the light source to a deflector; and

a second optical system that leads the light beams deflected from the deflector to a surface to be scanned, wherein

when it is assumed that a scanning direction of the light beams defected from the deflector is a main scanning direction and a direction orthogonal to the main scanning direction and to optical axes of both the first and the second optical systems is a sub scanning direction, a distance between the outermost light emitting diodes in the main scanning direction is longer than that in the sub scanning direction.

2. The optical scanning apparatus according to claim 1, wherein, when lateral magnification in the main scanning direction of an optical system between the light source and the surface to be scanned is β

m, and lateral magnification in the sub scanning direction of an optical system between the light source and the surface to be scanned is μ

s, then |β

m|>

|β

s|.

3. The optical scanning apparatus according to claim 1, wherein

in the light source, m (m≧

2) light emitting diodes are arranged along the sub scanning direction and n (n≧

2, m≦

n) light emitting diodes are arranged substantially in the main scanning direction, and

the light emitting diodes are arranged at a first equal interval in the sub scanning direction, two adjacent light emitting diodes in the main scanning direction are displaced by a second equal interval the sub scanning direction, and the light emitting diodes are arranged at a third equal interval in the main scanning direction.

4. The optical scanning apparatus according to claim 3, wherein, in the light source, when the first equal interval is d and the third equal interval is X, then X>

d.

5. The optical scanning apparatus according to claim 1, wherein the first optical system includes a coupling lens that couples the light beams emitted from the light source, and an aperture that limits the beams at least in the main scanning direction relative to the light beams emitted from the coupling lens, and the aperture is arranged at a position closer to the deflector rather than at a rear focal position of the coupling lens.

6. The optical scanning apparatus according to claim 1, wherein at least one of the outermost light emitting diodes has higher light emitting amount than any other of the light emitting diodes.

7. The optical scanning apparatus according to claim 1, wherein the first optical system includes a coupling lens that couples the light beams emitted from the light source, and an aperture that limits the beams in the main scanning direction and the sub scanning direction, and a width of the aperture in the main scanning direction is larger than that in the sub scanning direction.

8. An image forming apparatus that forms images by using the optical scanning apparatus according to claim 1.

9. An image forming apparatus that forms multicolor images by using the optical scanning apparatus according to claim 1.

10. An optical scanning apparatus comprising:

a light source including a two-dimensional array of light emitting diodes, each light emitting diode configured to emit a light beam;

a first optical system that leads the light beams emitted from the light source to a deflector; and

a second optical system that leads the light beams deflected from the deflector to a surface to be scanned, wherein

the first optical system includes

a coupling lens that couples the light beams emitted from the light source; and

an anamorphic lens that converts the light beams from the coupling lens in a line image extending in a main scanning direction,

a distance between outermost one of the light emitting diodes in the main scanning direction is longer than that in a sub scanning direction, and

the anamorphic lens has a positive power in the main scanning direction.

11. The optical scanning apparatus according to claim 10, wherein the first optical system includes a coupling lens that couples the light beams emitted from the light source, and an aperture that limits the beams in the main scanning direction and the sub scanning direction, and a width of the aperture in the main scanning direction is larger than that in the sub scanning direction.

12. The optical scanning apparatus according to claim 10, wherein at least one of the outermost light emitting diodes has higher light emitting amount than any other of the light emitting diodes.

13. An image forming apparatus that forms images by using the optical scanning apparatus according to claim 10.

14. An image forming apparatus that forms multicolor images by using the optical scanning apparatus according to claim 10.

15. An optical scanning apparatus comprising:

a light source including a two-dimensional array of light emitting diodes, each light emitting diode configured to emit a light beam;

a first optical system that leads the light beams emitted from the light source to a deflector; and

a second optical system that leads the light beams deflected from the deflector to a surface to be scanned, wherein

a distance between outermost of the light emitting diodes in a main scanning direction is longer than that in a sub scanning direction,

the first optical system includes

a coupling lens that couples the light beams emitted from the light source; and

an aperture that limits the optical beams emitted from the coupling lens in both the main scanning direction and the sub scanning direction, and

a width of the aperture in the main scanning direction is larger than that in the sub scanning direction.

16. The optical scanning apparatus according to claim 15, wherein at least one of the outermost light emitting diodes has higher light emitting amount than any other of the light emitting diodes.

17. An image forming apparatus that forms images by using the optical scanning apparatus according to claim 15.

18. An image forming apparatus that forms multicolor images by using the optical scanning apparatus according to claim 15.