JPH0590429U - Light deflector - Google Patents

Abstract

(57) [Summary] [Purpose] An object of the present invention is to have a rotary motion of a rotating body which is supported by bearing means provided on the outer periphery of a fixed shaft and rotate horizontally, and to prevent so-called unbalanced Scribe motion. [Structure] Annular grooves 4 and 4 are bored at positions where the bearing means 2 and 2 provided on the outer periphery of the fixed shaft 6 are in contact with the fixed shaft, and the elastic bodies 5 are arranged in the grooves 4 and 4, The unbalanced horizontal movement of the rotating body 10 is corrected by reducing the gap generated between the fixed shaft 6 and the bearing means 2, 2 by pressing the elastic body 5 in the radial direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotary multifaceted optical deflector used for optical scanning of a laser beam printer.

[0002]

[Prior Art]

 A conventional optical deflector will be described with reference to FIG. 2 of the accompanying drawings. Reference numerals 2 and 2 denote a pair of bearings, which are arranged on the outer periphery of the fixed shaft 6 and support a rotating body 10 having a hub 8. A predetermined preload is applied by a preload spring 3 existing between the bearings 2 and 2. There is. A rotating polygon mirror 12 is mounted on the hub 8 of the rotating body 10. The stationary shaft 6 is vertically erected by a stator 14 so as not to be displaced in the vertical direction, and a coil 18 is wound around an iron core 16 protruding horizontally by the stator 14. A drive magnet 22 is attached to the inside of a back yoke 20 having an L-shaped cross section fixed to the lower surface of the hub 8 of the rotating body 10 so as to face the coil 18, and a lower end of the back yoke 20 has a rotational speed F. for measurement Attach the G magnet 24. Reference numeral 26 is a printed circuit board, 28 is a lead wire, and 30 is a cover member.

By energizing the coil 18 to excite the iron core 16, the generated magnetic flux causes the magnet 22 to make a rotational motion due to its repulsive force, and the back yoke 20 to which the magnet 22 is attached rotates with the rotary polygon mirror 12 mounted. While being supported by the bearings 2 and 2 around the fixed shaft 6 together with the body 10, it is rotatable.

[0004]

[Problems to be solved by the device]

 The conventional optical deflector has the following problems. The bearings 2 and 2 provided on the outer periphery of the fixed shaft 6 are of the so-called outer ring rotating type, and therefore form a rotation support mechanism. The inner ring and the fixed shaft of each of the bearings 2 and 2 that are preloaded by the preload spring 3. Since there is a gap between the rotating body 10 and the rotating polygon mirror, the rotating body 10 is supported by the bearing 2 and rotates the outer circumference of the fixed shaft 6, and this gap causes the rotation of the rotating body 10 due to centrifugal force during rotation. The rotation of the body 10 becomes unbalanced, a so-called Scrigging motion is generated, and smooth horizontal rotation of the rotating body 10 becomes impossible. Therefore, the rotary polygon mirror 12 mounted on the rotary body 10 cannot rotate horizontally, and a plane tilt phenomenon occurs.

Therefore, when a beam of laser light or the like emitted from a predetermined position is reflected on the mirror surface of the rotating polygonal mirror 12 that is rotating, the reflected beam cannot be irradiated to the same predetermined position, so that there is an error at the beam arrival point. Occurs, and as a result, the performance of the optical deflector deteriorates.

[0006]

[Means for Solving the Problems]

 The purpose of the present invention is to solve the above-mentioned problems, and the means will be described below.

A rotary polygon mirror 12 is mounted on a rotating body 10 supported by bearing means 2 and 2 provided on the outer periphery of the fixed shaft, and the rotating body 10 is rotatably provided on the outer periphery of the fixed shaft 6. An annular groove 4 is bored on the outer circumference of the fixed shaft 6 which is in contact with the bearing means 2, 2 and an elastic O-ring 5 is arranged in this groove. , 2 are pressed, and one or more O-rings 5 and annular grooves 4 of the elastic body are provided for one bearing means 2 or one or more for a pair of bearing means 2, 2. It is an optical deflector.

[0008]

[Action]

 Since an annular groove is provided on the outer periphery of the fixed shaft that is in contact with the bearing means and an elastic body such as an O-ring is arranged in this groove, the bearing means is pressed in the radial direction by the elastic body O-ring. Therefore, when the rotating shaft is supported by the bearing means and rotates around the fixed shaft, backlash due to the clearance between the inner ring of the bearing means and the outer circumference of the fixed shaft is prevented, and the rotary polygon mirror mounted on the rotating body is prevented. The troublesome phenomenon can be eliminated.

[0009]

【Example】

 An embodiment of an optical deflector according to the present invention will be described below with reference to the accompanying drawings. In the embodiment of the present invention shown in FIG. 1, annular grooves 4 and 4 are bored on the surfaces of the fixed shaft 6 which a pair of bearings 2 and 2 provided on the outer periphery of the fixed shaft 6 contact. Elastic bodies such as O-rings 5 and 5 are housed in these annular grooves 4 and 4, respectively. The other components are the same as those of the conventional optical deflector described with reference to FIG. 2, and thus detailed description thereof will be omitted.

Since the bearings 2 and 2 are pressed in the radial direction by elastic bodies such as O-rings 5 and 5, when the rotating body 10 is supported by the bearings 2 and 2 and rotates around the fixed shaft 6, the bearing 2 is rotated. , 2 and the outer periphery of the fixed shaft 6 can be eliminated, and play due to this gap can be prevented. In other words, since the bearings 2 and 2 are maintained in a state of being pressed by the elastic body, for example, the O-rings 5 and 5, the force that causes the rotating body 10 to cause the so-called Scrigging motion is absorbed, and the rotating body 10 is A smooth horizontal rotary motion can be performed.

In this embodiment, a pair of bearings 2 and 2 and a pair of annular grooves 4 and 4 facing each other are provided, and elastic bodies such as O-rings 5 and 5 are provided in these grooves, respectively. However, the number of the bearings 2, the annular grooves 4, and the O-rings 5 to be adopted may be appropriately combined.

[0012]

【effect】

 In the present invention, an annular groove is bored in the outer periphery of the fixed shaft that contacts the bearing means provided in the outer periphery of the fixed shaft, and an elastic body such as an O-ring is arranged in this groove, and the elastic force of the O-ring is set. Since the bearing means is pressed in the radial direction by means of the bearing, when the rotating body is supported by the bearing and rotates around the fixed shaft, it prevents backlash due to the gap between the inner ring of the bearing and the outer periphery of the fixed shaft. As a result, it is possible to eliminate the surface tilt phenomenon of the rotating polygon mirror mounted on the rotating body, and it is effective in improving the performance of the optical deflector.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an optical deflector according to the present invention.

FIG. 2 is a vertical sectional view of a conventional optical deflector.

[Explanation of symbols]

 2 bearing 3 preload spring 4 annular groove 5 elastic body O ring 6 fixed shaft 8 hub 10 rotating body 12 rotating polygon mirror

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[Procedure amendment]

[Submission date] April 13, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

Claims (3)

[Scope of utility model registration request] 1. A rotary polygon mirror is mounted on a rotating body supported by bearing means provided on an outer periphery of a fixed shaft, and the rotating body is rotatably provided on the outer periphery of the fixed shaft so as to be in contact with the bearing means. An optical deflector in which an annular groove is formed on the outer periphery of the shaft, an elastic body is disposed in the groove, and the elastic means presses the bearing means in the radial direction. 2. The optical deflector according to claim 1, wherein the elastic body is an O-ring. 3. The optical deflector according to claim 1, wherein one or more elastic bodies and annular grooves are provided for one bearing means or one or more for a pair of bearing means.