Optical scanning device and image forming apparatus equipped with the same

Abstract

An optical scanning device is configured in such a manner that, of four light beams for colors corresponding to black, cyan, magenta, and yellow, the angle of the reflection surface of the last folding mirror disposed in the optical path of a light beam corresponding to an image in black having the lowest brightness and the highest visibility is closest to vertical, and further, the angle of the reflection surface of the last folding mirror disposed in the optical path of a light beam corresponding to an image in yellow having the highest brightness and the lowest visibility is closest to horizontal. It is thus possible to reduce a color shift in the color image caused by reflecting a light beam having passed through the correction lens on the last folding mirror.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view schematically showing the configuration of an image forming apparatus equipped with an optical scanning device according to one embodiment of the invention.

FIG. 2 is a view schematically showing the configuration of the optical scanning device shown in FIG. 1.

Claims

1. An optical scanning device, comprising: plural light sources that emit light beams corresponding to images using developing agents each having different brightness;a deflector that deflects plural light beams emitted from the plural light sources as the plural light beams go incident on a same reflection surface thereof at different angles of incidence in a sub-scanning direction;plural correction members that correct the plural light beams deflected by the deflector; andplural last reflection members that reflect the light beams corrected by the plural correction members to be distributed to surfaces of different photoconductors,wherein, of the plural last reflection members, a last reflection member provided in an optical path of a light beam corresponding to an image using a developing agent having lowest brightness is provided so that an angle of installation of a reflection surface of the last reflection member is closest to vertical.

2. The optical scanning device according to claim 1, wherein: of the plural last reflection members, a last reflection member provided in an optical path of a light beam corresponding to an image using a developing agent having highest brightness is provided so that an angle of installation of a reflection surface of the last reflection member is closest to horizontal.

3. The optical scanning device according to claim 2, wherein: each of the plural correction members corrects an error occurring in a corresponding light beam due to optical face tangle that the reflection surface of the deflector inclines with respect to a rotational axis of the deflector; andthe plural last reflection members are provided, one in each optical path, between the correction members and photoconductors provided correspondingly to the respective light beams.

4. The optical scanning device according to claim 1, wherein the plural light sources include: a first light source that emits a first light beam corresponding to an image using a black developing agent;a second light source that emits a second light beam corresponding to an image using a cyan developing agent;a third light source that emits a third light beam corresponding to an image using a magenta developing agent; anda fourth light source that emits a fourth light beam corresponding to an image using a yellow developing agent,wherein the plural last reflection members include:a first last reflection member that reflect the first light beam;a second last reflection member that reflects the second light beam;a third last reflection member that reflects the third light beam; anda fourth last reflection member that reflects the fourth light beams, andwherein an angle of installation of a reflection surface of the first last reflection member is more vertical than angles of installation of reflection surfaces of the second through fourth last reflection members.

5. The optical scanning device according to claim 4, wherein: an angle of installation of a reflection surface of the fourth last reflection member is more horizontal than angles of installation of reflection surfaces of the first through third last reflection members.

6. The optical scanning device according to claim 5, wherein: the first through fourth last reflection members are disposed sequentially along the sub-scanning direction.

7. An optical scanning device, comprising: plural light sources that emit light beams corresponding to images using developing agents each having different brightness;a deflector that deflects plural light beams emitted from the plural light sources as the plural light beams go incident on a same reflection surface thereof at different angles of incidence in a sub-scanning direction;plural correction members that correct the plural light beams deflected by the deflector; andplural last reflection members that reflect the light beams corrected by the plural correction members to be distributed to surfaces of different photoconductors,wherein, of the plural last reflection members, a last reflection member provided in an optical path of a light beam corresponding to an image using a developing agent having highest brightness is provided in such manner that an angle of installation of a reflection surface of the last reflection member is closest to horizontal.

8. An image forming apparatus, comprising: the optical scanning device set forth in claim 1; andplural photoconductors corresponding to the images using the developing agents each having different brightness.

9. An image forming apparatus, comprising: the optical scanning device set forth in claim 7; andplural photoconductors corresponding to the images using the developing agents each having different brightness.