JPS61118719A - Rotary polygon mirror assembly - Google Patents

Abstract

PURPOSE:To assemble a polygon mirror with high precision and to eliminate the influence of heat generation, and to maintain a reflecting mirror surface with high precision by clamping and centering the rotary polygon mirror, fitted loosely on a rotating shaft, in a jig by a couple of clamping members, and making an angle adjustment with an adjusting screw. CONSTITUTION:One clamping member 6 are engaged with the rotating shaft 1 threadably to fit the rotary polygon mirror 8 loosely, and the centering jig 2 is fitted tightly onto the shaft 1; and the polygon mirror is fitted in a jig hole part 13 having the same internal diameter as the external diameter D of the polygon mirror and aligned to the shaft 1. Then, the other clamping member 16 is engaged threadably to fix the polygon mirror temporarily, and the jig 2 removed to adjust the tilt angle of the polygon mirror with adjusting screws 19 and 20 engaged threadably with the clamping members 6 and 16. Thus, the polygon mirror is assembled with high precision through the operation of the adjusting screws and fitted loosely on the shaft to eliminate the influence of rotary heat generation, thereby maintaining the reflecting mirror surfaces with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotating polygon mirror assembly used for scanning a laser beam on a photosensitive drum such as a laser grinter.

BACKGROUND ART Conventionally, in order to attach a rotating polygon mirror to a rotating shaft, a clamping member 103 is screwed onto a threaded portion 102 of a rotating shaft 101 as shown in FIGS. 3 and 4.
The hole 106 of the rotating polygon mirror 105 is fitted into the intermediate diameter part 104 formed to have a smaller diameter than the threaded part 102 at the front end of the threaded part 102 , and the clamping member 108 is fitted into the small diameter part 107 at the front end of the intermediate diameter part 104 .

Thus, the rotating polygon mirror 106 and the clamping member 108 are connected to the clamping part 10.
3, the rotating polygon mirror 106 is mounted on the rotating shaft 101 by tightening with a port 109 and a nut 110.

Problems to be Solved by the Invention In the above conventional rotating polygon mirror assembly, the rotating polygon mirror 10
5 and the rotating shaft 101 is determined by the fit of the hole 106. Therefore, the mounting precision of the rotating polygon mirror 105 is determined by the reference surfaces 111 and 112 of the clamping members 103 and 105 and the hole 106. Therefore, the rotating polygon mirror 10
6 will be installed later, in order to achieve high precision, the clamping members 103, 1
The reference planes 111 and 112 of 08 must be formed with high precision. In addition, since the hole 106 is tightly fitted into the intermediate diameter portion of the rotating shaft 101 and there is no gap between them, the clamping member 103,
The reference planes 111 and 112 of 108 cannot be fully activated. That is, not only can they not be completely used as a reference plane, but also adjustment using the reference planes 111 and 112 is impossible.

Furthermore, if there is a change in the concentration of the motor that drives the rotating shaft 1o1 or the surrounding area, the rotating shaft 101 and the rotating polygon mirror 105 are made of different materials (steel thread is used for the rotating shaft 1o1, and the rotating polygon mirror 105 is made of different materials. (using glass, aluminum, etc.)
The coefficients of thermal expansion are different, and distortion occurs in the rotating polygon mirror 106.

Therefore, according to the present invention, it is possible to assemble a rotating polygon mirror with high precision, and it is also possible to maintain high precision by minimizing the influence of heat generation from the rotating shaft, etc., and preventing the generation of distortion in the rotating polygon mirror. The present invention aims to provide such a rotating polygon mirror assembly.

Means for solving the problems The technical means of the present invention for solving the above problems are as follows:
A rotating shaft, a rotating polygon mirror formed with a hole that is loosely fitted to the rotating shaft, and a pair of clamps that hold the rotating polygon mirror, which is loosely fitted and centered with respect to the rotating shaft, on the rotating shaft. A member, a means for fixing the rotating polygon mirror to the rotating shaft while being sandwiched by these clamping members, and adjustment screws screwed together at multiple locations on the clamping member so that the rotating polygon mirror can move forward and backward relative to the rotating polygon mirror. be.

Effect of the Invention With the above-described configuration, the rotating polygon mirror can be adjusted with high precision with respect to the rotation axis using the adjustment screw of the clamping member. Furthermore, since the rotating polygon mirror is loosely fitted onto the rotating shaft to reduce the portion that comes into direct contact with it, even if the rotating shaft generates heat, the effect on the rotating polygon mirror can be minimized.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, a hole 4 in a base 3 of a centering jig 2 is tightly fitted into the rotating shaft 1.

A clamping member 6 is screwed into the threaded portion 5 of the rotating shaft 1 .

A hole 9 of a rotary polygon mirror 8 is loosely fitted into an intermediate diameter portion 7 which is formed to have a smaller diameter than the threaded portion 6 at the end of the threaded portion 6 of the rotating shaft 1 . As shown in FIG. 2, this rotating polygon mirror 8 has chamfers 11 formed so that the reflective mirror surfaces 10 are on the same circumference with a diameter D. On the other hand, the hole 13 of the fitting portion 12 on the distal end side of the centering jig 2 has an inner diameter tapered. The rotating polygon mirror 8 is fitted into the hole 13 of this fitting part 12, and the chamfered part 1
1 is in contact with the inner wall of the hole 13. Therefore, the hole 4 of the centering jig 2 fits into the rotating shaft 1, and the hole 13 of the centering jig 2 fits into the rotating polygon! l! Since the 80-chamfered portion 11 is a fit, the rotating polygon mirror 8 is centered with respect to the rotating shaft 1. A threaded portion 16 is formed in a small diameter portion 14 ahead of the intermediate diameter portion 7 of the rotating shaft 1, and a clamping member 16 is screwed into this threaded portion 15. In each clamping member 6, 16, screw holes 17, 18 are formed at equal intervals at 8 in the illustrated example, corresponding to the number of reflecting mirror surfaces 10 of the rotating polygon mirror 8. An adjustment screw 19°2 for adjusting the inclination angle of each reflecting mirror surface 1o in the rotating polygon mirror 8
o is screwed in. Therefore, the rotating polygon mirror 8 is temporarily fixed by the holding members 6 and 16 and the adjusting screws 19 and 20.

Then, the centering jig 2 is removed from the temporarily fixed state, the rotating shaft 1 is rotated, and the inclination angle of each reflecting mirror surface 1o of the rotating polygon mirror 8 is measured using a collimator. Then adjust screw 1
By operating the rotating polygon mirrors 9 and 20, the rotating polygon mirror 8 is loosely fitted to the rotating shaft 1 and has a gap, so that the rotating polygon mirror 8 can be corrected and the installation work is completed.

Note that the clamping member 6 may be formed integrally with the rotating shaft 1,
Further, as a means for fixing the rotating polygon mirror 8 to the rotating shaft 1, a clamping member 16 is fitted into the small diameter portion 14 of the rotating shaft 1, and the rotating polygon mirror 8 and the clamping member 16 are connected to the clamping member 6 by a port and a nut. You can do it like this. Furthermore, the rotating polygon mirror 8 is chamfered 11 between each reflecting mirror surface 8 so as not to be damaged when fitting into the hole 13 of the centering jig 2 and performing centering work. It doesn't necessarily have to be done.

Effects of the Invention As is clear from the above explanation, according to the present invention, a centering jig is removably supported on a rotating shaft, and a rotating polygon mirror loosely fitted on the rotating shaft is fitted into the centering jig. The rotating polygon mirror is centered with respect to the rotating shaft, and the rotating polygon mirror is held on the rotating shaft by a pair of clamping members, and is fixed to the rotating shaft by a fixing means. We are making it possible for them to advance and retreat. Therefore, by operating this adjustment screw, the rotating polygon mirror can be easily assembled to the rotating shaft with high precision. In addition, since the rotating polygon mirror is loosely fitted onto the rotating shaft to reduce the amount of direct contact, the effect of heat generated by the rotating shaft during rotation can be extremely minimized, making it possible to maintain a highly accurate reflective mirror surface. can.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing an embodiment of the rotating polygon mirror assembly of the present invention, FIG. 2 is a front view of the rotating polygon mirror used in the present invention, and FIG. 3 is a conventional rotating polygon mirror assembly. FIG. 4 is a front view of the rotating polygon mirror. 1... Rotating shaft, 2... Centering jig, 6
・−・・Holding member, 8・・・・Rotating polygon mirror, 1
0... Reflecting mirror surface, 16... Holding member,
19.20...Adjustment screw. 351st 4rM

Claims (1)

[Claims] A pair of rotating polygon mirrors each having a rotating shaft, a rotating polygon mirror formed with a hole that is loosely fitted to the rotating shaft, and a rotating polygon mirror that is loosely fitted and centered with respect to the rotating shaft, and which are sandwiched on the rotating shaft. The gripping member includes a means for fixing the rotary polygon mirror to the rotating shaft while being clamped by the clamping members, and adjustment screws that are screwed at a plurality of locations on the clamping member so as to be movable toward and away from the rotary polygon mirror. A rotating polygon mirror assembly characterized by: