Optical element holder, light scanning unit, and image forming apparatus

Abstract

An optical element holder is provided with a holding frame having a side surface provided spaced apart by a specific distance from an end portion of the correction lens in a longitudinal direction by deeming a light scanning direction as the longitudinal direction and holding the correction lens so as to cover the correction lens except for at least an incident portion and an exiting portion of light, and a pushing member that pushes the correction lens toward the holding frame, so that displacement in the light scanning direction due to heat of the optical element is lessened.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section showing the configuration of a copying machine according to one embodiment of the invention.

FIG. 2 is a perspective view of a laser scanner unit shown in FIG. 1.

FIG. 3 is a schematic cross section of the laser scanner unit shown in FIG. 1.

FIG. 4 is an exploded perspective view of a correction lens unit shown in FIG. 2 and FIG. 3.

FIG. 5 is a perspective view used to describe a method of fixing the correction lens shown in FIG. 4 after it is inserted into a holding frame.

FIG. 6A is a top view of the correction lens unit shown in FIG. 2 and FIG. 3, FIG. 6B is a front view of the correction lens unit shown in FIG. 2 and FIG. 3, FIG. 6C is a cross section taken on line 6C-6C′ of FIG. 6B, FIG. 6D is a cross section taken on line 6D-6D′ of FIG. 6B, FIG. 6E is an enlarged view of the right end of the correction lens and the holding frame shown in FIG. 6B.

FIG. 7 is a perspective view showing a state where the correction lens units are removed from the laser scanner unit shown in FIG. 2 and FIG. 3.

FIG. 8 is a plan view showing the configuration of the laser scanner unit shown in FIG. 2 and FIG. 3.

FIG. 9A is an enlarged plan view of an end portion of the correction lens unit in the laser scanner unit shown in FIG. 2 and FIG. 3, FIG. 9B is an enlarged side view of an end portion of the correction lens unit in the laser scanner unit shown in FIG. 2 and FIG. 3.

FIG. 10 is a schematic cross section of a laser scanner unit in a tandem-type image forming apparatus in the related art.

Claims

1. An optical element holder, comprising: a holding frame having a side surface provided spaced apart by a specific distance from an end portion of a correction lens in a longitudinal direction by deeming a light scanning direction as the longitudinal direction and holding the correction lens so as to cover the correction lens except for at least an incident portion and an exiting portion of light; anda pushing member that pushes the correction lens toward the holding frame.

2. The optical element holder according to claim 1, wherein: the specific distance is equal to or longer than an extensible distance of the correction lens in the longitudinal direction due to thermal expansion.

3. The optical element holder according to claim 1, wherein: the pushing member is provided substantially at a center of the correction lens in the longitudinal direction.

4. The optical element holder according to claim 3, wherein: the holding frame has two side surfaces provided spaced apart by a specific distance from both end portions of the correction lens in the longitudinal direction.

5. The optical element holder according to claim 4, wherein: the pushing member pushes the correction lens toward the holding frame along an optical axis direction of the correction lens.

6. The optical element holder according to claim 5, wherein: the pushing member further pushes the correction lens toward the holding frame along a direction orthogonal to the optical axis direction and the light scanning direction of the correction lens.

7. The optical element holder according to claim 1, wherein: the holding frame is shaped using an aluminum die cast.

8. A light scanning unit, comprising: a light source portion having plural light sources;a rotary polyhedron to deflect beams of light emitted from the plural light sources;plural correction lenses to form images of the beams of light emitted from the plural light sources and deflected by the rotary polyhedron on corresponding image carriers;the optical element holder set forth in claim 1 to hold at least one of the plural correction lenses; anda housing to which the optical element holder is fixed,wherein the optical element holder is fixed to the housing at both end portions of the holding frame.

9. The light scanning unit according to claim 8, wherein: the optical element holder further comprises supporting shafts provided to the both end portions of the holding frame;V-shaped groove portions to hold the supporting shafts are provided to the housing; andthe light scanning unit further comprises an elastic member that presses the supporting shafts to the groove portions in a state where the supporting shafts are adjustable in a rotatable manner with respect to the groove portions.

10. The light scanning unit according to claim 8, wherein: rigidity of the holding frame is higher than rigidity of the housing.

11. An image forming apparatus, comprising: the light scanning unit set forth in claim 8; andplural image forming units that form images using beams of light emitted from the light scanning unit.