JPS58136014A - Assembling method of optical deflector - Google Patents

Abstract

PURPOSE:To adjust slanted mirror surfaces by pressing polygon mirrors slanted at a prescribed angle to a turntable having fitting grooves in an axial direction in the optical deflector of a projector and then pressing the polygon mirrors against the fitting grooves with a bolt. CONSTITUTION:Polygon mirrors 1-a-1-h are worked previously to have an acute angle theta to the center of rotation and fixed to the turntable 2 having fitting grooves 10-a-10-b with bolts 9-a-9-d. Respective mirror surfaces 1-a- 1-b are deformed by adjusting clamping forces F1 and F2 of the bolts 9-a-9-b to adjust angles to the turntable 2, thus improving the scanning position precision of a deflected light beam. In this case, bolt holes 9-1-9-b are in the center of respective mirror surfaces 1-a-1-b, 1-d, and 1-g and the polygon mirror body 1 is so deformed that gaps of the fitting grooves 10-a and 10-b of the turntable 2 are clamped.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of assembling an optical deflection device using a rotating polygon mirror, and aims to improve the accuracy of the scanning position of a deflected light beam.

In general, copiers, computer terminal printers, etc.
2. Description of the Related Art It is widely used to deflect a light beam using a light deflection device using a rotating polygon mirror.

In general, it is important for devices to which a light deflection device is applied that the deflected light flux accurately reach a predetermined target. Figure 1 shows a device that applies a conventional optical deflection device, which modulates the output light amount of a laser 4 in synchronization with input information, deflects the laser light by rotating a polygon mirror 1, and rotates in synchronization. The photosensitive drum 7 is scanned as shown in FIG. 6. A latent image is electrostatically formed on the photosensitive drum 7 according to the amount of laser light, and after being developed by a developing device (not shown),
The image is transferred and fixed onto the paper 8 and printed. In this device, the focal position of the focusing lens 6 is set on the frontmost generatrix 6 of the photosensitive drum, and if it is scanned off the generatrix 6, the resulting printed matter will change. is out of focus, or overlaps or separates from the previous and subsequent scan lines, causing jitter.

Therefore, it is necessary for the deflected light beam to accurately scan the position of the generatrix 6 on the surface of the photosensitive drum 7.

However, it is very difficult to accurately keep the scanning position of the deflected light beam constant.

In general, mechanical errors in the scanning position of the optical deflection light beam using a rotating polygon mirror are caused by processing errors of the polygon mirror itself, bending of the rotary table on which it is mounted, and swinging of the polygon mirror due to rattling of the bearing. .

In particular, in the rotating polygon mirror portion, as shown in FIG. 2, the polygon mirror 1 was directly fixed to the rotating table 2 with pins 9-a and 9-b. Therefore, in order to improve the accuracy of the scanning position, the parts processing and assembly adjustment of the optical deflection device must be performed extremely precisely.
Alternatively, measures such as providing a separate optical system for scanning position correction have been taken. In order to eliminate these drawbacks, JP-A-55-157715 and JP-A-56-6211 disclose that simply eliminating the whirling of the polygon mirror 1 due to the bending of the rotary table 2 and the wobbling of the bearing is quite effective. In order to improve the deflection accuracy, a flexible member is interposed between the polygon mirror 1 and the rotary table 2, and the scanning position is improved by the action of fluid pressure.

However, these optical deflection devices have the disadvantage that they have a complicated structure and an increased number of parts.

The present invention solves the above-mentioned conventional drawbacks, and embodiments thereof will be described below with reference to FIGS. 3 to 6.

In Figures 3 to 5, 1 is a polygon mirror, 1-a to 1-h are each mirror surface, 2 is a rotary table on which the polygon mirror 1 is attached, and 3 is a rotary table 2.
a high-speed motor 9 that rotationally drives the polygon mirror 1 fixed to the
- a to 9-d are bolts for fixing the polygon mirror 1 to the rotary table 2, and 10-a to 1o-b are grooves of the rotary table 2 provided at the deformation watchdogs of the polygon mirror 1.

In the above configuration, each mirror surface 1-a to 1-h of the polygon mirror 1 is processed in advance so as to form an acute angle θ with respect to the center of rotation, as shown in FIG. This polygon mirror 1 is attached to the bolt 9-a
Rotating table 2 having mounting grooves 10-a to 10-b at ~9-d
Fixed to. At this time, in order to improve the scanning position accuracy of the deflected light beam, the tightening by Pol) 9-a to 9-b is performed on each mirror surface 1-a to 1 by adjusting the force F1 to F2.
-b is deformed as shown by the broken line in FIG. 5, and the angle formed with the rotating table 2 serving as the base is adjusted. In this case, as shown in FIG.
, 1-d, 1-q (D center VC position L, the polygon mirror 1 is deformed so as to reduce the gap between the mounting grooves 10-a and 10-b of the rotary table 2.

Therefore, in the optical deflection device according to the present invention, the polygon mirror 1 is mounted on the rotary table 2 having the mounting grooves 10-a and 10-b with the bolts 9-
They are fixed at points a to 9-d, and the optical axis can be easily adjusted by adjusting the tightening force so that the deflected light beam can accurately reach a predetermined target. Moreover, the structure of the optical deflection device itself is simple, and the deflection accuracy can be improved without increasing the number of parts.

In the above embodiment, it is assumed that the polygon mirror 1 is fixed and adjusted by the rotary table 2 having the grooves 10-a and 10-b. The structure may be flexible as long as there is a gap between the polygon mirror 1 and the rotary table 2, and the tightening force is applied to reduce the gap.

As described above, according to the present invention, the structure of the optical deflection device itself is simple, and the scanning position accuracy of the deflected light beam can be improved.

[Brief explanation of drawings]

6 houses - Fig. 1 is a perspective view of a device to which the optical deflection device is applied, Fig. 2 is a sectional view of a conventional example, Fig. 3 is a plan view of an optical deflection device according to an embodiment of the present invention, and Fig. 4 is the same sectional view, and FIG. 5 is the same sectional view showing the effects of the present invention. 1 , , , , polygon mirror, 1a to 1 h , , , ,
, mirror surface, 2. . ...Rotating table, 3...High speed motor, 4...
...Laser, 6...Focusing lens, 6...
...Bus bar, 7...Photosensitive drum, 8...
...Paper, 9a-9d...10.・Bolt, 10a
, 10 b , , , groove. Name of agent: Patent attorney Toshio Nakao Haga 1 person No. 3
Figure 4 Figure 5 Figure 1 □

Claims (1)

[Claims] A polygon mirror is formed by forming a regular polygon with a predetermined angle around an axis, and the mirror surface is tilted at a predetermined angle with respect to the axial direction, and is attached to a rotary table having a mounting groove in the axial direction with bolts,
A method for assembling an optical deflection device in which the tilted mirror surface can be adjusted by pressing a polygon mirror into the mounting groove with a bolt.