JPH0651229A - Deflection scanning device - Google Patents

Abstract

PURPOSE:To surely and readily hold the rotating polygon mirror of a deflection scanning device in place and to reduce the assembling cost of the device. CONSTITUTION:A cover member 28 made from synthetic resin and used to hold a rotating polygon mirror 26 via an elastic annular bendable portion 27 is mounted on a rotor portion 25, and six holding portions 29 for holding the six edge portions of the rotating polygon mirror 26 are projected inward at the inner periphery of the upper portion of the cover member 28, the upper face of each holding portion 29 being slanted. To hold the rotating polygon mirror 26 in place, the rotating polygon mirror 26 is pushed in from above the holding portions 29 and the bendable portion 27 of the cover member 28 is bent and the mirror is held in place beneath the holding portions 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection scanning device used in a laser beam printer, a copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, a deflection scanning device is used in a laser beam printer or the like to deflect and scan a laser beam. FIG. 8 is a plan view of such a deflection scanning device,
FIG. 9 shows a cross-sectional view of a main part. A laser beam emitted from a laser oscillator 1 passes through a collimator lens 2 and a cylindrical lens 3, is reflected by a rotary polygon mirror 6 fixed to a rotary shaft 5 of a drive motor 4, and fθ After passing through a spherical lens 7 and a toric lens 8 which form a lens system, the light is further reflected by a reflection mirror 9 and scans on a photosensitive drum (not shown).

Each member other than the photosensitive drum is attached to the scanner body 10, and particularly the rotary polygon mirror 6 is pressed by a G ring 13 attached to the rotary shaft 5 via a corrugated fixing member 11 and a washer 12. It is fixed in the closed state. As described above, since the rotary polygon mirror 6 is pressed and fixed from above, the rotary polygon mirror 6 does not slide with respect to the rotary shaft 5 even if the rotary shaft 5 rotates.

[0004]

However, the above-mentioned conventional example has the following drawbacks. (1) When the G-ring 13 is attached to the rotary shaft 5 by an automatic machine, the G-ring 13 is fitted to the rotary shaft 5 and then pushed down to a predetermined position. Therefore, the rotary shaft 5 has 15 kgf to 20 kgf.
A certain amount of force may be applied downward, and the bearings of the drive motor 4 may be damaged.

(2) The position at which the rotary polygon mirror 6 is pressed and fixed is 3
Since only about points can be provided and the distance between the rotation center and the pressing position cannot be increased, the fixed state of the rotary polygon mirror 6 tends to become unstable.

(3) When the rotary polygon mirror 6 rotates, a wind noise is likely to be generated around its periphery.

(4) In order to fix the rotary polygon mirror 6, the corrugated spring 11, the washer 12, the G ring 13 and the like must be used, which increases the number of parts and the number of assembling steps, resulting in high cost.

(5) Since the position of the center of gravity of the G ring 13 does not coincide with the center of rotation, the rotary polygon mirror 6 may be eccentric during rotation.

It is an object of the present invention to solve the above-mentioned problems, to securely and simply fix the rotary polygon mirror to the drive motor, and to provide a deflection scanning device which reduces wind noise generated by the rotation of the rotary polygon mirror. To provide.

[0010]

A first deflection scanning device for achieving the above object is a deflection scanning device for deflecting and scanning a light beam emitted from a light source by a rotating polygon mirror by rotating a drive motor. The rotary polygon mirror is mounted on the drive motor, the rotor portion of the drive motor is surrounded by a cover member, and a holding portion for holding the rotary polygon mirror is provided on the cover member, and the holding portion holds the rotary polygon mirror. The edge between the mirror surfaces of the rotary polygon mirror is fixed from above.

A second deflection scanning device is a deflection scanning device in which a rotating polygon mirror is deflected for scanning a light beam emitted from a light source by rotating a driving motor, and the rotating polygon mirror is mounted on the driving motor. The rotor part of the drive motor is surrounded by a cover member, the upper part of the cover member is fixed to the rotary shaft of the drive motor, and a holding part for holding the rotary polygon mirror is provided on a part of the cover member. The parts are connected to each other via a spring part formed between the cover member and a mounting part of the rotor part, and a window part is provided in the cover member corresponding to the mirror surface of the rotary polygon mirror.

[0012]

In the first deflection scanning device having the above-mentioned structure, the cover member that surrounds the rotor portion of the drive motor is integrally formed with the holding portion that holds the rotary polygon mirror, and the rotary polygon mirror is held by the holding portion. By suppressing the edge part from above, it is possible to simplify the fixing of the rotary polygon mirror and to reduce wind noise when rotating at high speed.

In the second deflection scanning device, the cover member surrounding the rotor portion of the drive motor is fixed to the rotary shaft, and the rotary polygon mirror is held by the holding portion via the spring portion. Achieves simplification of fixing method and noise reduction of wind noise at high speed rotation.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the embodiments shown in FIGS. FIG. 1 is a sectional view of the first embodiment, FIG.
Is a plan view. A sleeve 22 is fixed to the bottom of the scanner body 21, and a rotary shaft 23 is rotatably fitted to the sleeve 22. The flange 2 is located in the middle of the rotary shaft 23.
4 is fixed, the rotor portion 25 of the drive motor is fixed to the lower portion of the flange 24, and the rotary polygon mirror 26 having six mirror surfaces is placed on the upper portion of the flange 24. The rotor portion 25 has a cover member 28 made of synthetic resin that holds the rotary polygon mirror 26 via an elastic ring-shaped flexible portion 27.
Are attached, and six holding portions 29 for suppressing the six edge portions of the rotary polygon mirror 26 are provided on the inner periphery of the upper portion of the cover member 28 so as to project inward, and the upper surface of the holding portion 29 is It is an inclined surface. It should be noted that the cover member 28 is provided with a window portion for allowing the laser beam to enter and exit the mirror surface of the rotary polygon mirror 26. The cover member 28 is integrally molded with a plastic magnet, and the flexible portion 27 is designed to bend within a force of several kgf so that no more force is applied to the rotor portion 25 from above. It has become.

To fix the rotary polygon mirror 26, the rotary polygon mirror 26 is fitted on the rotary shaft 23, and the edge portion of the rotary polygon mirror 26 is aligned with the holding portion 29 of the cover member 28 attached to the rotor portion 25. When the rotary polygon mirror 26 is pushed down, the rotary polygon mirror 26 temporarily stays on the holding portion 29. However, when the rotary polygon mirror 26 is pushed further in, the flexible portion 27 bends outward and the rotary polygon mirror 2 moves.
6 passes through the inclined surface and moves below the holding portion 29, and is pressed and fixed from above by the holding portion 29.

As described above, the rotary polygon mirror 26 is pressed and fixed by the stopper 29 in the thrust direction and covered and fixed by the cover member 28 in the radial direction. At this time, since the flexible portion 27 prevents the force of several kgf or more from being transmitted, the rotary shaft 23 is not excessively pressed downward. Further, the edge part of the rotary polygon mirror 26 is held by the holding part 29.
Since it is pressed and fixed by, the rotary polygon mirror 26 is stably fixed. Further, since the mirror surface of the rotary polygon mirror 26 is covered with the cover member 28, the wind noise is prevented from leaking to the outside. The laser beam is scanned through the window provided on the cover member 28.

FIG. 3 is a sectional view of the second embodiment, the first
The same reference numerals as those in the above embodiment indicate members having substantially the same function. A protrusion 28 is provided on the inner surface of the cover member 28 that covers the rotor portion 25, and the cover member 28 is attached to the rotor portion 25 by fitting the protrusion 28 a into the groove 25 a provided around the rotor portion 25. ing. As a result, the same configuration as that of the first embodiment can be obtained, and substantially the same operational effect can be obtained.

When the cover member 28 is molded from a molding material having a small friction coefficient such as polyacetal, the work of fitting the cover member 28 to the rotor portion 25 and the work of placing the rotary polygon mirror 26 on the flange 24 are required. It will be easier.

FIG. 4 is a sectional view of the third embodiment, in which the rotary polygon mirror 26 is covered and fixed by a cover member 31 molded from a molding material such as polyacetal.
The cover member 31 is, as shown in FIGS.
5, the covering portion 32 surrounding the upper part of the outer peripheral surface and the rotary polygon mirror 2
The holding portion 33 for restraining 6 is connected to the shaft attachment portion 34 fixed to the rotary shaft 23 via four inclined flexible portions 35 that bend within a force of several kgf. On the inner peripheral surface of the shaft mounting portion 34, a mounting projection 34 that fits into the groove portion 23 a of the rotary shaft 23.
a is provided, and the cover member 31 is fixed to the rotary shaft 23 by fitting the mounting projection 34a into the groove 23a. In addition, a pressing projection 33 a that comes into contact with the upper surface of the rotary polygon mirror 26 is provided on the lower surface of the holding portion 33 in the radial direction of the flexible portion 35, and further, the cover member 31.
At a position corresponding to the mirror surface of the rotating polygon mirror 26 of FIG.
Is provided.

To fix the rotary polygon mirror 26, after the rotary polygon mirror 26 is placed on the flange 24, the cover member 3 is attached.
1 so as to cover the rotary polygon mirror 26 and the rotor portion 25,
The mounting protrusion 34a of the shaft mounting portion 34 is formed in the groove portion 2 of the rotary shaft 23.
The shaft mounting portion 34 is pushed down until it is fitted into 3a. At this time, the pressing projection 33a comes into contact with the upper surface of the rotary polygon mirror 26 to bend the flexible portion 35, and presses the rotary polygon mirror 26 by the spring force of the flexible portion 35a, and at the same time, the mounting projection 34a.
Is in sliding contact with the rotary shaft 23, and the rotary shaft 23 is pressed downward.

The cover member 31 is molded from polyacetal or the like having a small frictional force, and the flexible portion 35 thereof is designed to bend within a force of several kgf.
The rotary shaft 23 is not excessively pressed even if it slides on the rotary shaft 23, and the drive motor is not damaged. In addition, after the mounting projection 34a is fitted into the groove 23a,
The cover member 31 is pressed upward by the rotary polygon mirror 26, but the rotary polygon mirror 26 is fixed by a predetermined force because the shaft mounting portion 34 is fixed to the rotary shaft 23. Further, since the pressing projection 33a comes into contact with the rotary polygon mirror 26, that is, the pressing position is near the outer peripheral edge of the rotary polygon mirror 26, the rotary polygon mirror 26 is fixed with a stable force. Further, since the outer peripheral edge of the rotary polygon mirror 26 is covered with the covering portion 32, the wind noise is prevented from leaking to the outside.

FIG. 7 is a cross-sectional view of the fourth embodiment, in which a cover member 41 molded from a synthetic resin material has a flexible portion between a cover portion 42 surrounding the rotor portion 25 and a holding portion 43. 44 is provided so as to bulge outward, the inner peripheral direction of the holding portion 43 is flat, and a large diameter hole 45 is formed. Further, the rotor portion 25 is provided on the inner peripheral surface of the lower end of the cover member 42.
An annular fixing protrusion 42a that fits in the groove portion 25b provided around the groove is provided. The fixing protrusion 42a is formed in the groove portion 25b.
By fitting the cover member 41 into the rotor portion 25,
It is designed to be fixed to. Further, a pressing projection 43 a that comes into contact with the rotary polygon mirror 26 is provided on the lower surface of the holding portion 43, and a window portion 46 is provided on the cover member 42 at a position corresponding to the mirror surface of the rotary polygon mirror 26.

To fix the rotary polygon mirror 26, after the rotary polygon mirror 26 is placed on the flange 24, the cover member 4 is attached.
1 so as to cover the rotary polygon mirror 26 and the rotor portion 25,
The fixing projection 42a of the covering portion 42 is fitted into the groove portion 25b. The operational effect of the flexible portion 44 at this time is similar to that of the third embodiment.

The cover member 28 and the like may be formed of, for example, an elastic stainless plate instead of a synthetic resin material such as polyacetal.

[0025]

As described above, the first deflection scanning device is easy to assemble and rotates at high speed because the edge of the rotary polygon mirror is fixed by a part of the cover member surrounding the rotor portion of the drive motor. Wind noise is also reduced.

In the second deflection scanning device, the cover member surrounding the rotor of the rotary polygon mirror drive unit fixes the rotor by applying a spring force, so that the assembly is easy and the wind noise during high-speed rotation is reduced. To do.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment.

FIG. 2 is a plan view.

FIG. 3 is a sectional view of a second embodiment.

FIG. 4 is a sectional view of a third embodiment.

FIG. 5 is a perspective view of a cover member.

FIG. 6 is a sectional view.

FIG. 7 is a sectional view of a fourth embodiment.

FIG. 8 is a plan view of a conventional deflection scanning device.

FIG. 9 is a sectional view of a main part of a conventional example.

[Explanation of symbols]

 23 rotary shaft 25 rotor part 26 rotary polygon mirror 27, 31, 44 flexible part 28, 32, 41 cover member 29, 33, 43 holding part 36 window part

Claims (3)

[Claims] 1. A deflection scanning device in which a drive motor is rotated to deflect and scan a light beam emitted from a light source by a rotary polygon mirror, wherein the rotary polygon mirror is mounted on the drive motor.
A rotor member of the drive motor is surrounded by a cover member,
A deflection scanning device characterized in that a holding portion for holding the rotary polygon mirror is provided on an upper portion of the cover member, and an edge between mirror surfaces of the rotary polygon mirror is fixed from above by the holding portion. 2. A deflection scanning device for rotating a drive motor to deflect and scan a light beam emitted from a light source by a rotary polygon mirror, wherein the rotary polygon mirror is mounted on the drive motor.
The rotor part of the drive motor is surrounded by a cover member, the upper part of the cover member is fixed to the rotary shaft of the drive motor, and a holding part for holding the rotary polygon mirror is provided on a part of the cover member. Part is connected via a spring part formed between the cover member and a mounting part of the rotor part, and a window part is provided in the cover member corresponding to the mirror surface of the rotary polygon mirror. Scanning device. 3. The deflection scanning device according to claim 2, wherein a step portion for positioning the cover member is provided on the rotary shaft.