JPH08201716A - Deflection scanning device - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce noise caused by vibration of the iron substrate when the deflection mirror rotates. [Structure] A thickness of 0.01 m is provided between a motor housing 35 of a motor equipped with a rotary polygon mirror 23 and an iron substrate 41.
An iron substrate 41 with a plate-shaped synthetic resin member 42 of m or more interposed therebetween.
Attach.

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 having a rotating device such as a polygon mirror supported by bearings in an image forming device such as a laser beam printer.

[0002]

2. Description of the Related Art As shown in FIG. 8, a rotating device in a conventional deflection scanning device has a motor housing 3 fixed by screws 2 in an optical box 1 of the deflection scanning device, and a ball bearing 4 provided in the motor housing 3. The motor shaft 5 is rotatably supported by.

A washer-shaped fixing member 7 to which a rotor 6 is attached by caulking or the like is press-fitted onto the motor shaft 5, and a rotary polygon mirror 8 is fixed onto the rotor 6. A drive magnet 9 is fixed to the lower surface of the rotor 6 with an adhesive or the like. Below that, the motor housing 3
An iron substrate 11 that constitutes an electric circuit is provided on the upper side of the motor housing 3 with screws 2 and a stator coil 10 is provided on the upper surface thereof. The drive magnet 9 and the stator coil 10 drive the motor shaft 5. The rotary polygon mirror 8 is adapted to rotate.

Although not shown, the optical box 1 also contains optical means (not shown) for condensing the light beam on the surface to be scanned, and when the motor shaft 5 rotates, it is rotated by the rotary polygon mirror 8. The light beam is deflected and scanned.

[0005]

However, recently, in order to improve heat dissipation and prevent temperature rise in the apparatus,
Further, the iron substrate 11 is often used as an electric circuit substrate for chip mounting by reflow due to an increase in mounting density.

On the other hand, the iron substrate 11 has the advantages as described above, but since the iron substrate 11 and the motor housing 3 are assembled by the screws 2 as shown in FIG. A gap A of 0.005 to 0.01 mm is likely to occur. Therefore, the vibration generated by the rotation of the rotary polygon mirror 8 causes the motor housing 3 to vibrate in the direction of the arrow B, causing the motor housing 3 and the iron substrate 11 to move to the motor shaft 5,
The rotor 6 and the rotary polygon mirror 8 collide with the rotating body at the same frequency as the rotating frequency, and as a result, the iron substrate 11 and the motor housing 3 collide with each other to generate vibration noise. Further, since the natural frequency of the iron substrate 11 is about 200 to 300 Hz, if the rotation speed of the rotor 6 exceeds 10,000 rpm,
There is a problem that the vibrating sound is further amplified by resonating with the iron substrate 11, and the noise causes noise at its frequency.

It is an object of the present invention to provide a deflection scanning device which reduces noise due to vibration when the deflection mirror rotates.

[0008]

A deflection scanning device according to the present invention for achieving the above object comprises a deflection mirror, a rotating body for rotating the deflection mirror, and an iron plate for driving the rotating body. In an apparatus having an electric circuit board made of metal, a housing made of a metal material for supporting the rotating body, and an optical box made of a synthetic resin material for holding the rotating body, the housing and the electric circuit board are combined at a mounting portion. It is characterized in that a resin member is sandwiched.

[0009]

In the deflection scanning device having the above-described structure, the synthetic resin member attenuates the transmission of the vibration generated from the rotating body to the iron substrate when the deflection mirror rotates, and
The resonance frequency of the iron substrate and the rotating body can be shifted by using the synthetic resin member.

[0010]

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 plan view showing the configuration of the first embodiment. The device body 20 is arranged in the optical box 21,
A rotary polygon mirror 23 is directly connected to the motor 22, and a semiconductor laser light source 24 for irradiating a light beam toward a deflection reflection surface 23a of the rotary polygon mirror 23 is provided. A collimator is provided between the rotary polygon mirror 23 and the semiconductor laser light source 24. Lens 25
And a cylindrical lens 26. Further, a reflecting mirror 27 is provided along the exit window 21a of the optical box 21, and an fθ lens 28 including lenses 28a and 28b is provided between the reflecting mirror 27 and the deflecting / reflecting surface 23a.

A light beam emitted from the semiconductor laser light source 24 is made into a parallel light beam by a collimator lens 25, linearly condensed on a rotary polygon mirror 23 by a cylindrical lens 26, and deflected and reflected by a deflective reflection surface 23a.
The light enters the reflecting mirror 27 through the fθ lens 28 and is reflected by the reflecting mirror 2
It is reflected by 7 and scans on a photoreceptor not shown.

The light beam reflected by the deflecting / reflecting surface 23a is focused by the fθ lens 28 so as to form a spot on the photosensitive member, and the spot scanning speed is designed to be kept constant. . In order to obtain such characteristics of the fθ lens 28, the fθ lens 28 is composed of two lenses, a spherical lens 28a and a toric lens 28b.

Then, by the rotation of the rotary polygon mirror 23,
Main scanning is performed by the light beam on the photoconductor, and sub-scanning is performed by rotating the photoconductor about the axis of the cylinder. In this way, an electrostatic latent image is formed on the surface of the photoconductor.

Around the photoconductor, a corona discharger for uniformly charging the surface of the photoconductor, and a visible image for developing an electrostatic latent image formed on the surface of the photoconductor into a toner image. Device,
A transfer corona discharger for transferring the toner image onto the recording paper is arranged, and the recording information corresponding to the luminous flux generated by the semiconductor laser light source 24 is formed on the recording paper by these functions.

The irradiation position of the deflection scanning device is adjusted by the positioning pins 31 and 32 provided outside the optical box 21. 33 is a guide hole for the positioning pin 31,
Reference numeral 34 is a guide hole for the positioning pin 32. Device body 2
For adjusting the irradiation position in the x direction of 0, the positioning pins 31 and 3
This is done by moving both 2 to the same side in the x direction. Further, the adjustment of the device body 20 in the θ direction in FIG. 1 is performed by moving the positioning pin 31 and the positioning pin 32 to opposite sides in the x direction, respectively.
Performs rotational movement in the θ direction.

Here, in the motor 22 of the deflection scanning device, as shown in FIG. 2, a motor shaft 37 is rotatable by a bearing 36 press-fitted and fixed in a motor housing 35 made of brass or the like provided in the optical box 21. Supported by. A washer-shaped fixing member 38 is press-fitted into the motor shaft 37 by shrink fitting, the rotor 39 is fixed to the peripheral edge of the fixing member 38, and the rotary polygon mirror 23 is fixed on the fixing member 38.

A drive magnet 40 is fixed to the inner surface of the rotor 38 with an adhesive, and an iron substrate 41 is provided below the drive magnet 40.
5 is assembled via a plate-shaped synthetic resin member 42 having a thickness of 0.01 mm or more with the upper surface of 5, and a stator coil 43 is provided on the upper surface of the iron substrate 41.
When the synthetic resin member 42 is made of silicon, vinyl, or acrylic, it is desirable that the hardness thereof is shore D80 or less so that it can be easily deformed.

In the deflection scanning device thus constructed, the synthetic resin member 42 is sandwiched between the iron substrate 41 and the motor housing 35 as shown in FIG. The synthetic resin member 42 is deformed by the force at the time of assembling and fills the gap generated by the warp of the iron substrate 41 and the like. As shown in FIG. 4, the relationship between the thickness of the synthetic resin member 42 and the noise generated in the deflection scanning device is such that when the thickness exceeds 0.01 mm, the damping effect rapidly increases and exceeds 0.1 mm. The damping effect becomes almost constant from the time point.

In the description of the embodiment, the ball bearing is used as an example of the bearing, but other known various bearings may be used.

FIG. 5 is a sectional view of the motor portion of the second embodiment. In this embodiment, an anaerobic curable resin is used as the synthetic resin member 50. A liquid pool 51a is provided on the upper surface of the motor housing 51, and the synthetic resin member 50 is filled in the liquid pool 35a.

Since the synthetic resin member 50 is liquid when the iron substrate 41 and the housing 51 are assembled, it completely fills the gap generated by the assembly and hardens after assembly by an anaerobic effect. Therefore, the adhesion between the iron substrate 41 and the synthetic resin member 50 is greater than that in the first embodiment, and a greater effect is exhibited in reducing vibration noise. The hardness of the synthetic resin member 50 after curing is determined by the iron substrate 41.
In order to prevent the peeling due to the difference in thermal expansion from the above, it is preferable that the shore D is 80 or less.

FIG. 6 is a sectional view of the motor portion of the third embodiment. In this embodiment, the synthetic resin member 60 is integrally formed with the motor housing 61 by a method such as insert molding. Therefore, it is advantageous in terms of assemblability and component management, and contributes to cost reduction.

FIG. 7 is a sectional view of the motor portion of the fourth embodiment. In this embodiment, the portion of the housing 70 other than the base portion 35b having the mounting reference plane K is made of the synthetic resin member 7.
It is molded by 1. Therefore, the number of metal members can be reduced, and the cost can be further reduced.

[0024]

As described above, in the deflection scanning device according to the present invention, since the synthetic resin member is sandwiched between the mounting portions of the motor housing and the iron substrate, when the deflection mirror rotates,
The transmission of the vibration generated from the rotating body to the iron substrate can be attenuated by the synthetic resin member, and the resonance frequency of the iron substrate can be shifted by the synthetic resin member to reduce the noise caused by the vibration of the iron substrate.

The thickness of the synthetic resin member is 0.01 mm.
With the above, noise reduction becomes more effective.

Further, if the synthetic resin member is an anaerobic curable resin, the adhesion to the iron substrate is improved, so that the vibration noise can be further reduced.

If the motor housing and the synthetic resin member are integrally molded, or if the motor housing is molded by the synthetic resin member other than its mounting base, the vibration noise is reduced and the assembling work is reduced to reduce the cost. be able to.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a motor portion.

FIG. 3 is a partially enlarged view.

FIG. 4 is a diagram showing the correlation between the thickness of a synthetic resin member and vibration noise.

FIG. 5 is a sectional view of a motor portion of a second embodiment.

FIG. 6 is a sectional view of a motor portion of a third embodiment.

FIG. 7 is a sectional view of a motor portion according to a fourth embodiment.

FIG. 8 is a cross-sectional view of a motor portion of a conventional example.

FIG. 9 is a partially enlarged view thereof.

[Explanation of symbols]

 20 Device Main Body 22 Motor 23 Rotating Polyhedral Mirror 35, 51, 61, 70 Motor Housing 41 Iron Substrate 42, 50, 60, 71 Synthetic Resin Member

Claims (4)

[Claims] 1. A deflection mirror, a rotating body for rotating the deflection mirror, an electric circuit board made of an iron plate for driving the rotating body, a housing made of a metal material for supporting the rotating body, and A deflection scanning device comprising an optical box made of a synthetic resin material for holding a rotating body, wherein a synthetic resin member is sandwiched between mounting portions of the housing and the electric circuit board. 2. The deflection scanning device according to claim 1, wherein the heat of the synthetic resin material is 0.01 mm or more. 3. The deflection scanning device according to claim 1, wherein the synthetic resin material is an anaerobic cured resin. 4. The deflection scanning device according to claim 1, wherein the housing and the synthetic resin material are integrally molded.