JP2003075756A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely adjust the front and rear positions of a collimating lens in a compact optical device. SOLUTION: By holding a movable part including the collimating lens by two springs, the movable part including the collimating lens is stably adjusted in terms of the front and rear positions. Furthermore, by providing a groove part in the vicinity of a contact point of a cylindrical holder with the movable part including the collimating lens, the front and rear positions of the movable part including the collimating lens to an optical axis are precisely adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device used in an electrophotographic apparatus.

[0002]

2. Description of the Related Art In recent years, with the downsizing of electrophotographic devices, the mounting space for optical scanning devices has become limited. Therefore, as in the conventional optical system, a sufficient optical path length cannot be obtained from the light beam emission to the surface to be scanned (hereinafter referred to as the photoconductor surface), and it is very delicate to obtain the required light beam spot diameter on the photoconductor surface. Need to be adjusted.

In the optical system in the conventional electrophotographic apparatus,
As shown in FIG. 4, a collimator lens is arranged in a cylindrical holder, and it is moved back and forth for fine adjustment. In FIG. 4, reference numeral 10 indicates a movable portion including a collimating lens, and the movable portion 10 is adjusted back and forth in a cylindrical support portion 11. In this adjusting method, there is a possibility that the movable portion 11 that is not held may move unless bonding is performed after the adjustment.

Further, as shown in FIG. 5, a screw portion 12 and a spring (spring) 13 are provided in front of and behind the movable portion in the optical axis direction,
In some cases, the movable portion 10 including the collimator lens 3 is adjusted back and forth by rotating the screw portion 12. In FIG.
If the structure is movable back and forth, a gap is always generated between the components of the movable portion 10 and the support portion 11. Therefore, the collimator lens may move in this gap after the adjustment.

Further, as shown in FIG. 6, in order to prevent the vertical movement within the fitting size of the collimator lens, the movable part 10
There is also a mechanism provided with a spring 14 for pushing the side surface of the. 1 is a semiconductor laser, 2 is a laser beam, 3 is a collimating lens, 10 is a movable part including a collimating lens,
Reference numeral 11 is a cylindrical support portion, 12 is a screw portion for adjusting the front and rear, 13
Is a coil spring, and 14 is a spring for pressing the collimator lens. At this time, the clearance due to the fitting between the movable portion including the collimating lens 10 and the support portion 11 is
By being pushed by the spring 14, the gap a becomes maximum,
It becomes almost constant with the minimum gap b.

FIG. 7 shows a sectional view of the vicinity of the spring 14 shown in FIG. At this time, the direction f perpendicular to the spring 14
A gap c and a gap d are generated in This gap may change due to an external force after the adjustment is completed, and at that time, the size of the beam spot diameter at the time of adjustment may also change. Therefore, the state is unstable in the vertical direction f with respect to the pressing direction e, and the cost increases as the number of parts increases.

In the current design of an optical device having a small size and a short optical path, there is a problem that the adjustment value fluctuates even with the above movement.

[0008]

As described in the prior art, as the size of the electrophotographic apparatus becomes smaller, the short circuit becomes shorter. Along with this, the distance between the light beam emitting portion and the collimator lens becomes narrow, and the positional relationship between the collimator lens and the semiconductor laser becomes very sensitive. Therefore, even if the collimator lens moves up and down in the fitting gap that exists between the cylindrical support portion and the movable portion including the collimator lens in the adjusted optical device, the adjustment value will be incorrect. there is a possibility. Further, when the bonding is performed, the collimator lens may be pulled by the solidification of the adhesive and may move up and down to cause the adjustment value to change. Further, there is a problem in that the fine adjustment after bonding causes a great increase in the number of steps.

[0009]

[Means for Solving the Problems] By arranging the collimator lens to be pressed by springs from two directions, the gap between the collimator lens and the holder can be made constant, and the adjusted collimator lens optical axis direction. It is also possible to hold the upper, lower, left and right positions with respect to. That is, the position of the collimator lens can be adjusted easily and accurately.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a schematic view of the entire optical device.
The laser beam 2 emitted from the semiconductor laser 1 in the printing area is collimated by the collimator lens 3, collimated by the cylinder lens group 4 to reduce the vertical and horizontal diameters thereof, and is imaged once on the polygon mirror 5 and then scanned. It The laser beam 2 scanned by the polygon mirror 5 is
After being spread on the Fθ lens 6, it is again narrowed down and reflected by the return mirror 7, and then only the vertical diameter is further narrowed down by the long cylinder lens 8 to be scanned on the photoconductor surface 9.

This embodiment is shown in FIGS. 1 and 2.

FIG. 1 is a view seen from the laser axis direction.
The spring 14 is arranged so as to be pressed at an angle g and an angle h from the horizontal center of the movable portion 10 including the collimator lens. At this time, 0 ° <g≈h <90 °. As a result, the movable part including the collimating lens has two springs 1.
4 and the cylindrical support portion 11 are in contact with each other at three points, and the gaps i and j are always constant.

FIG. 2 is a sectional view of the optical system of FIG. 1 taken along the laser axis. The gap k is maximum and the gap l is minimum and almost constant. As described above, the movable portion including the ten collimating lenses is stably held by being pressed against the spring 14 with sufficient overload. It is possible to omit the screw portion for adjusting the front and rear and the coil spring which are conventionally used. Further, since the length of the movable portion 10 including the collimating lens can be lengthened by the elimination of the screw portion for front-back adjustment, the amount of tilting is reduced accordingly.

Further, as shown in FIG. 8, a cylindrical support portion 11
The movable portion 10 including the collimator lens is provided by providing a groove near the contact point between the movable portion 10 including the collimator lens and
Is determined by the two edges q and r of the groove, and the gaps m and n are completely constant. At this time, the width m of the groove is smaller than the width p of the movable portion 10 including the collimating lens.
As a result, even if the distance between the semiconductor laser 1 and the movable portion 10 including the collimator lens is designed to be short, the adjustment of the position of the collimator lens in the optical axis direction may cause positional deviation in the vertical and horizontal directions with respect to the optical axis. You can do it. In addition, since there is no positional deviation of the collimator lens after adjustment in front, back, up, down, left and right, it is possible to precisely adjust the beam spot diameter even with a small optical device.

[0016]

According to the present invention, even in a small-sized optical device, the movable portion including the collimator lens is fixed by using two springs, and the cylindrical holder is provided with a positioning groove. Therefore, it is possible to adjust the beam spot diameter on the drum surface stably at a low cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an optical system including a collimator lens that is an embodiment of the present invention.

FIG. 2 is a schematic diagram of an optical system including a collimator lens that is an embodiment of the present invention.

FIG. 3 is a schematic diagram of an optical scanning device.

FIG. 4 is a schematic diagram of an optical system including a conventional collimating lens.

FIG. 5 is a schematic diagram of an optical system including a conventional collimating lens.

FIG. 6 is a schematic diagram of an optical system including a conventional collimating lens.

FIG. 7 is a schematic diagram of an optical system including a conventional collimating lens.

FIG. 8 is a schematic diagram of an optical system including a collimator lens that is another embodiment of the present invention.

[Explanation of symbols]

1 ... Semiconductor laser, 2 ... Laser beam, 3 ... Collimating lens, 4 ... Cylinder lens group, 5 ... Polygon mirror, 6 ... FTH lens, 7 ... Return mirror, 8 ... Long cylinder lens, 9 ... On photoconductor surface, 10 ... Movable part including collimating lens, 11 ... Supporting part, 12 ... Screw part for front-back adjustment, 13 ... Coil spring, 14 ... Spring, 15
… Supporting part.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) G02B 7/02 B41J 3/00 D

Claims (2)

[Claims] 1. A light beam generation means for generating one or a plurality of independent light beams, a deflection means for reflecting the generated light beams by a deflection surface to deflect the light beam, a surface to be scanned, and deflection. Image forming optical system having an Fθ characteristic for forming an image of the light beam deflected by the scanning means on the surface to be scanned, and optical scanning of an electrophotographic apparatus for scanning the scanning surface by the light beam deflected by the deflecting means. In the device, a collimator lens that collimates a light beam immediately after the light beam emitting portion, a movable portion for adjusting the collimator lens back and forth, a support portion for housing the movable portion, and a plurality of movable portions on the side surface of the support portion. An optical scanning device comprising a plurality of springs which are pressed from the direction. 2. The optical scanning device according to claim 1, wherein the supporting portion is provided with a groove for positioning.