JPH06202028A - Scanning optical device - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the vibration of the scanning optical device and improve the image quality and life. [Structure] Motor unit 1 equipped with rotary polygon mirror 14
The elastic member 21 is provided between the circuit board 20 of 8 and the optical box 11. The elastic member 21 is formed such that the ribs 23 and 24 are orthogonal to each other, and the rib 23 is provided with a hole through which the screw 22 is inserted.
Is provided with a boss that fits into the holes 20a and 20b of the circuit board 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device used for laser printers and laser facsimiles.

[0002]

2. Description of the Related Art In a conventional scanning optical device, FIG.
As shown in the plan view, the laser light emitted from the laser device 1 becomes parallel light by the collimator lens 2 and becomes linear light by the cylindrical lens 3 and enters the rotary polygon mirror 4. The reflected light reflected by the rotary polygonal mirror 4 becomes an imaged light by the spherical lens 5 and the toric lens 6 which form the f-θ lens system, is reflected by the reflecting mirror 7 to the outside of the optical box 8, and is reflected by a photoconductor (not shown). Incident. An electrostatic latent image is formed on the photoconductor by the incident light, and the electrostatic latent image is visualized as a toner image by a developing device (not shown). This visible image is transferred to a recording sheet, and then heated and fixed by a fixing device (not shown).

On the other hand, the rotary polygon mirror 4 is fixed to a motor unit 10 having a circuit board 9 as shown in the sectional view of FIG. In addition, the housing 1 of the motor unit 10
After 1 is fitted in the reference hole 8a of the optical box 8, the motor unit 10 is fixed to the optical box 8 with screws 12, and the circuit board 9 is fixed to the optical box 8 with screws 13.

[0004]

However, in the above-mentioned conventional example, when the rotary polygon mirror 4 rotates at high speed, self-excited vibration is generated in the circuit board 9. This vibration is transmitted to the optical box 8 and vibrates the optical box 8 and the photoconductor, and the relative position between the optical box 8 and the photoconductor changes, resulting in uneven pitch in the image. Further, if the number of screws 13 is increased in order to reduce such vibration, the circuit board 9 is bent, and the electric elements and print patterns attached to the circuit board 9 are broken. Furthermore, noise is generated due to vibration, and the motor unit 1
There is also a problem that the life of 0 becomes short.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a scanning optical device with less vibration and excellent image quality.

[0006]

A scanning optical device according to a first aspect of the present invention for achieving the above object houses a motor unit for rotating a rotary polygon mirror in an optical box, and a circuit board of the motor unit. In the scanning optical device having the optical box fixed to the optical box, an elastic member is provided between the circuit board and the optical box.

A scanning optical device according to a second aspect of the present invention is a scanning optical device in which a motor unit for rotating a rotary polygon mirror is housed in an optical box, wherein the motor unit is provided with an elastic member. .

[0008]

In the scanning optical device according to the first aspect of the invention having the above-mentioned structure, the elastic member is provided between the circuit board and the optical box, and the vibration of the circuit board is damped by the elastic member.

Further, in the scanning optical device according to the second aspect of the present invention, the motor unit is provided with the elastic member, and the vibration of the motor unit is attenuated by the elastic member.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a plan view of the first embodiment, in which a laser device 12 for emitting a laser beam is fixed to an optical box 11, and the laser beam is collimated in the traveling direction of the emitted laser beam. Collimator lens 1
3, a rotary polygon mirror 14 that deflects parallel light, a spherical lens 15 and a toric lens 16 that image the deflected light, and a reflecting mirror 17 that reflects the imaged light to the outside of the optical box 11 are sequentially arranged. A photoconductor (not shown) that receives the reflected light from the reflecting mirror 17 is installed outside the optical box 11.

On the other hand, the rotary polygon mirror 14 is the motor unit 1
The motor unit 18 is fixed to the optical box 11 with screws 19. The circuit board 20 of the motor unit 18 is fixed to the optical box 11 with screws 22 via elastic members 21 as shown in the perspective view of FIG. The elastic member 21 is made of rubber or the like, and has two ribs 23 and 2.
4 are orthogonal to each other. Screws 22 on ribs 23
Through holes 25 are provided, and the ribs 24 are provided with bosses 26 and 27 that fit into the holes 20a and 20b of the circuit board 20, respectively.

When the circuit board 20 is fixed to the optical box 11 with such a structure, the elastic member 21 is arranged between the circuit board 20 and the optical box 11, and the bosses 26 and 27 are provided in the hole 20a of the circuit board 20. , 20b respectively, and the circuit board 2
From above 0, the screw 22 is passed through the hole 25 of the elastic member 21 and fixed.

Therefore, the optical box 11 does not generate vibration due to the presence of the elastic member 21.

FIG. 3 is a perspective view of the second embodiment, in which a snap fit 28 is attached to the hole 25 of the elastic member 21 so that the circuit board 20 and the optical box 11 are directly fixed by the snap fit 28. It has become.

FIG. 4 is a sectional view of the third embodiment, showing a motor unit portion. The configuration of the entire apparatus is the same as that of the embodiment shown in FIG. Motor unit 3
A rotary shaft 34 is rotatably attached to the housing 32 of No. 1 via a bearing 33, and a flange 35 is attached to the rotary shaft 34.
Is fixed. The rotary polygon mirror 3 is provided on the flange 35.
6 is placed, and the rotary polygon mirror 36 is fixed by a stopper plate 38 fixed to the rotary shaft 34 by being preloaded by a spring 37. A yoke 40 having a drive magnet 39 on its inner peripheral surface is fixed to the lower surface of the flange 35.
An FG magnet 41 for controlling rotation is fixed to the lower end of the outer edge of 0. A circuit board 42 is fixed on the upper surface of the housing 32, and a stator coil 43 is fixed on the circuit board 42 so as to face the drive magnet 39. In addition, the FG magnet 4 is provided on the circuit board 42.
The FG pattern 44 is fixed so as to face 1. Further, an elastic member 46 made of thermoplastic resin is provided between the bottom of the housing 32 and the optical box 45, and the motor unit 31 is fixed to the optical box 45 with a screw 47. In addition, in the reflection direction of the rotary polygon mirror 36, an optical box 47
An imaging lens 48 and a photoconductor 49 attached to the are provided.

As described above, since the elastic member 46 is formed of the thermoplastic resin, the vibration of the motor unit 31 which is 333 Hz at 20,000 rpm caused by the rotation of the rotary polygon mirror 34 is efficiently generated by the elastic member 46. Attenuated.

FIG. 5 is a sectional view of the fourth embodiment, in which a damping steel plate 50 is provided in place of the elastic member 46 of the thermoplastic resin of the third embodiment. In this damping steel plate 50, as shown in FIG. 6, the elastic member 51 has metal members 52a and 52a.
It is in the form of a sandwich sandwiched between b.

When vibration is transmitted to the vibration damping steel plate 50, the vibration damping steel plate 50 is deformed as shown in FIG. 7, and the vibration is attenuated to 10 to several tens of kHz.

FIG. 8 is a sectional view of the fifth embodiment, in which the optical box 53 is fixed to the scanner mounting plate 54 with screws 55, and the housing 32 is a reference hole 53 of the optical box 53.
The elastic member 46 is provided between the bottom surface of the housing 32 and the scanner mounting plate 54 by being fitted to the a.

Also in this case, since the vibration is damped by the elastic member 46, the vibration is neither transmitted to the outside nor transmitted from the outside to the inside. Note that, in this embodiment as well, as in the fourth embodiment, the damping steel plate 50 may be used instead of the elastic member 46.

FIG. 9 is a sectional view of the sixth embodiment, in which an elastic member 46 is provided between the bottom of the housing 32 and the optical box 45, and the optical box 45 and the scanner mounting plate 54 are further provided.
The elastic member 55 is also provided between them.

In this case, since the vibration is damped by the elastic member 46 and further by the elastic member 55, the vibration of the scanner mounting plate 55 becomes extremely small.

[0023]

As described above, in the scanning optical device according to the first aspect of the present invention, the vibration is damped by the elastic member, so that the optical box does not vibrate and the image quality is improved. Also,
The circuit board does not bend, and the electric elements, printed patterns, etc. do not break.

Further, in the scanning optical device according to the second aspect of the invention, since the vibration is damped by the elastic member, the vibration of the optical box and the generation of noise are prevented, and the life of the motor unit is extended.

[Brief description of drawings]

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

FIG. 2 is a perspective view of an elastic member.

FIG. 3 is a perspective view of an elastic member according to a second embodiment.

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

FIG. 5 is a side view of the fourth embodiment.

FIG. 6 is a side view of a damping steel plate.

FIG. 7 is an operation explanatory diagram.

FIG. 8 is a sectional view of a fifth embodiment.

FIG. 9 is a sectional view of a sixth embodiment.

FIG. 10 is a plan view of a conventional example.

FIG. 11 is a sectional view of a conventional example.

[Explanation of symbols]

 11, 45 Optical box 14, 36 Rotating polygon mirror 20, 42 Circuit board 21, 46, 55 Elastic member 28 Snap fit 32 Housing 50 Damping steel plate 54 Scanner mounting plate

Claims (6)

[Claims] 1. A scanning optical device in which a motor unit for rotating a rotary polygon mirror is housed in an optical box, and a circuit board of the motor unit is fixed to the optical box, and a scanning optical device is provided between the circuit board and the optical box. A scanning optical device comprising an elastic member. 2. The scanning optical device according to claim 1, wherein the elastic member is formed in a rib shape. 3. The scanning optical device according to claim 1, wherein the elastic member is in contact with an end portion of the circuit board. 4. A scanning optical device in which a motor unit for rotating a rotary polygon mirror is housed in an optical box, wherein the motor unit is provided with an elastic member. 5. The scanning optical device according to claim 4, wherein the elastic member is provided at a substantially center of gravity position of the motor unit. 6. The scanning optical device according to claim 4, wherein the elastic member is provided between the motor unit and the optical box, and / or between the optical box and a mounting plate for mounting the optical box.