JPH10268223A - Optical deflection device and assembling method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the assembling method of an optical deflection device capable of fixing a polygon mirror for stably providing a scanning image of high quality to the outside cylinder of radial shaft without improving the machining accuracy and the assembling accuracy of each part. SOLUTION: In an optical deflection device for performing optical scanning by rotating the outside cylinder 102 of a radial shaft fixing a polygon mirror 101 to a fixed inside cylinder of a radial shaft, a fitting part 101B engaged with the outer periphery of the outside cylinder 102 of a radial shaft with high accuracy and an adhesive part 101C interposing some clearance are formed, the position is controlled by the engagement of the fitting part 101B, adhesive is filled in the adhesive part 101C, the tilt angle of the polygon mirror 101 to the outside cylinder 102 of a radial shaft is adjusted before hardening of adhesive and fixed it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light deflecting device used for optical scanning in an image recording device such as a laser printer, and a method of assembling the light deflecting device.

[0002]

2. Description of the Related Art In an image recording apparatus such as a laser beam printer, a laser beam is incident on a polygon mirror rotating at a high speed based on information read as writing means of the image, and the reflected light is scanned on the photosensitive member surface. The image is recorded by projection. FIG. 4 is a perspective view of a writing optical system to which the light deflecting device 100 is mounted. The output laser light from the semiconductor laser 1 becomes parallel light by the collimator lens 2 of the beam shaping optical system, passes through the first cylindrical lens 3 and is reflected and deflected by the polygon mirror 101 of the optical deflector 100. The beam is transmitted through the second cylindrical lens 5, subjected to beam correction, and projected on the photosensitive drum 6 via the reflecting mirror 5 at a predetermined spot diameter in the sub-scanning direction. Synchronization detection for each line
This is performed by causing the light beam before the start of scanning to enter the synchronization detector 8 via the mirror 7.

In such a scanning optical system, even a slight inclination angle error of the polygon mirror causes scanning unevenness on the screen, resulting in image distortion and degraded image quality. This becomes more remarkable by rotating the polygon mirror at a high speed to increase the recording density.

[0004] In the case of low-speed rotation, the polygon mirror is used directly fixed to the rotating shaft of the motor. However, in the case of high-speed rotation, the polygon mirror is fixed to the radial shaft outer cylinder and touches the radial shaft inner cylinder. The drive rotation is performed using an air bearing that rotates in a floating manner. The present applicant has disclosed a technology of an optical polarizing device having a dynamic pressure bearing portion in each specification such as Japanese Patent Application Laid-Open Nos. 7-243439, 7-259849, 8-114219 and 8-112471. FIG. 5 shows a cross-sectional configuration of an optical polarization device having a dynamic pressure bearing portion including an upper thrust plate 124, a lower thrust plate 123, and a radial shaft inner cylinder 125. In FIG. 5, the radial shaft inner cylinder 125 and the lower thrust plate 1 are concentric with the base 121.
The dynamic pressure bearing unit 120 is configured by attaching the coil 23 constituting the static magnetic field of the motor to the dynamic pressure bearing unit 120. Also,
A ring-shaped magnet 106 for the rotating magnetic field, an outer ring portion 104 made of aluminum, a radial shaft outer cylinder 102 made of ceramic, a polygon mirror 101 and a mirror retainer 103 are formed by the outer ring portion 104 and the mirror retainer 103 and a polygon mirror 101.
Are sandwiched in a sandwich shape and concentrically and integrally assembled to form a rotor 110. After the rotor 110 is fitted into the radial shaft inner cylinder 125, the upper thrust plate 1
24 is concentrically fixed to the radial shaft inner cylinder 125. A gap S of about 3 to 10 μm is formed between the radial shaft inner cylinder 125, the lower thrust plate 123, the upper thrust plate 124 and the upper and lower surfaces of the radial shaft outer cylinder 102 and the fitted inner peripheral surface. At the time of rotation, the rotor 110 floats up in the air without touching the dynamic pressure bearing portion 120, and the smooth rotation is maintained.

[0005]

In order to obtain good image quality, it is necessary to reduce the tilt angle of the polygon mirror, and the machining accuracy of the polygon mirror, the rotor portion to which the polygon mirror is fixed, and the dynamic pressure bearing portion are reduced. In addition, the assembly processing accuracy must be particularly high.

Means for minimizing the angle of inclination of the polygon mirror depend on increasing the accuracy of each component and the accuracy of assembly as described above. It requires great skill and the production cost is very high. In addition, when the thermal expansion coefficients are different between parts, it is inevitably difficult to maintain stable accuracy and durability.

The present invention solves the problems of the prior art and eliminates the effects of thermal expansion and the like by reducing the number of parts without particularly increasing the processing accuracy and assembly accuracy of each part.
High-speed stability of the optical deflector is ensured by reducing vibration fluctuations,
Optical deflecting device and method of assembling optical deflecting device capable of fixing polygon mirror to radial-axis outer cylinder capable of stably obtaining high-quality scanned images by reducing flatness fluctuation and improving image quality The purpose is to provide.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical deflector which performs optical scanning by rotating a radial shaft outer cylinder having a polygon mirror fixed to a fixed radial shaft inner cylinder. The engaging portion with the outer cylinder has an adhesive portion facing with a gap, the gap between the adhesive portions is filled with an adhesive, and the polygon mirror and the radial shaft outer cylinder are integrally fixed. A polygonal mirror, wherein the polygonal mirror is fixed to a fixed radial shaft inner cylinder, and the polygonal mirror is fixed to the radial shaft outer cylinder. The engagement portion between the mirror and the radial shaft outer cylinder has an adhesive portion opposed with a gap, and the polygon mirror in the engagement relationship can adjust the inclination angle with respect to the radial shaft outer cylinder. The method of assembling an optical deflecting device according to claim 4, further comprising: filling the gap between the bonding portions with an adhesive, and fixing the polygon mirror and the radial shaft outer cylinder integrally. ).

It is preferable that the polygon mirror and the radial shaft outer cylinder have different gap portions for positioning and filling with an adhesive at the bonding portion, and the adhesive has a longitudinal elastic modulus in a solidified state. 7000kg
f / mm ² or more and a thermal expansion coefficient of 2 × 10 ⁻⁵ / ° C. or less are preferable.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of an embodiment of the present invention, a sectional view of an optical deflecting device in which the assembling method of the present invention is preferably used will be described. FIG. 1 shows this, in which the number of components requiring high-precision processing is reduced as compared with the cross-sectional configuration of a conventional optical deflector (FIG. 5), and the tilt angle of each mirror surface is reduced by the adjustment method described later. The polygon mirror 101 and the radial shaft outer cylinder 102 in the adjusted state are integrally fixed using an adhesive. That is, the ring-shaped magnet 106 for the rotating magnetic field is integrally attached to the polygon mirror 101, and the outer ring portion 104 and the mirror retainer 1 which are conventionally assembled by sandwiching the polygon mirror 101 in a sandwich shape.
03 was abolished. Conventionally, when the polygon mirror 101 was sandwiched and fastened in a sandwich shape, the flatness of the mirror fluctuated, and the deformation and vibration were likely to occur due to the difference in the coefficient of thermal expansion between the components. I have.

In the method of assembling the light deflecting device according to the present invention, the polygon mirror is integrally fixed to the radial shaft outer cylinder by using an adhesive in a well adjusted state, but FIG. 2 shows the light deflecting device. FIG. 3 is a cross-sectional configuration diagram of an adjusting device illustrating an example of an adjusting method of FIG. The radial shaft outer cylinder 102 is a shaft fixing means 201.
Has been fixed by. On the outer periphery of the shaft fixing means 201, there is provided a rotating means 202 which rotates about the axis of the radial shaft outer cylinder 102, and the rotating means 202 is rotated by the rotation of the motor M1. Rotating means 20
On the upper surface of 2, a polygon mirror 101 extrapolated to a radial shaft outer cylinder 102 has a positional relationship of approximately 120 ° with respect to each other.
Placed by point support. One of the three-point supports is a fixed fixed support part 212, and the other two points of the polygon mirror 101 including push members 401A and 401B that operate in the direction of pushing in parallel with the axial direction of the polygon mirror 101. Tilt angle adjusting devices 400A, 400B
It is. (Only the tilt angle adjusting device 400A is shown in the figure. The tilt angle adjusting device 400B has the same configuration.) Also, reference numeral 300 denotes the polygon mirror 101.
Is a tilt angle measuring device for measuring the tilt angle of the mirror surface 101A. The light source 301 irradiates the mirror surface 101A in a spot shape, and the light receiving element 302 receives light reflected from the mirror surface 101A. The tilt angle of the mirror surface 101A is measured depending on the position. The control unit 200 drives the motor M1 to rotate the rotating means 202, thereby rotating the polygon mirror 101, which is a rotating polygon mirror placed on the upper surface, measuring the tilt angle of each mirror surface 101A, and determining the tilt angle. Calculate the variation. The control unit 200 controls the tilt angle adjusting device 400 according to a preset program.
A, 400B of the push members 401A, 401B are finely adjusted, and the variation of the tilt angle after the fine movement adjustment is measured and calculated. Adjust until the variation of the tilt angle falls within the allowable range.

The method of assembling the optical deflecting device of the present invention uses the polygon mirror 10
The polygon mirror 10 is adjusted with the tilt angle of 1 adjusted.
An adhesive is filled into an engaging portion between the first and radial shaft outer cylinders 102 to be integrated. FIG. 3 shows a plan view and a cross-sectional view of a main part indicated by each arrow in the embodiment of the present invention.

In the example shown in FIG. 3 (a), the polygon mirror 101 is engaged with the radial shaft outer cylinder 102 by a positioning fitting portion 101B which is relatively short in the axial direction at the bottom of the engaging portion. The joint position is regulated, and the upper adhesive portion 101C in the axial direction is filled with an adhesive and fixed.
The adhesive is injected from the injection port in the entire circumferential direction and is fixed integrally over the entire circumference.

In the example shown in FIG. 3B, the polygon mirror 101 is relatively short in the axial direction at the bottom and the top of the engaging portion with respect to the radial shaft outer cylinder 102.
B is engaged with the loose joint portion 101D having a looser fitting relationship with B, and the intermediate adhesive portion 101C is filled with an adhesive and fixed. The filling of the bonding portion 101C with the adhesive is performed by the injection port 1 opened in the upper mating portion 101D.
01E, bonding is performed over the entire circumference. By adopting such a shape and injecting the adhesive into the bonding portion 101C from the injection port 101E, the dispersion of the application of the adhesive is reduced, and the effect of reducing the dispersion of the adhesive strength is produced.

In the example shown in FIG. 3C, the polygon mirror 101 is relatively short in the axial direction at the bottom of the engaging portion with respect to the radial shaft outer cylinder 102.
B and the loose portion 101D, which is in a looser fitting relationship with the second portion B, is provided with several, for example, three, adhesive portions 101C in the axial direction of the loose portion 101D. And bonding is performed. By adopting such a shape, the adhesive is effectively used,
With a relatively small amount of the adhesive, the required adhesive strength is secured, and a strong integration is achieved.

Polygon mirror 1 made of pure aluminum or the like
Reference numeral 01 denotes a diagonal length of the polygon mirror of 30 mm to 80 mm, and the length L in the axial direction of the engaging portion between the polygon mirror 101 and the radial shaft outer cylinder 102 made of ceramic or the like is generally 3 mm to 12 mm. Spacing is often used.
The difference between the inner diameter and the outer diameter (D ₁ −
D ₂ ) is set to 2 × 1 mm register, and the polygon mirror 101 is bonded to the radial shaft outer cylinder 102 in a state where the inclination angle of the polygon mirror 101 is adjusted. In addition, each bonding part 101C
When the difference (D ₁ -D ₂ ) between the inner diameter and the outer diameter is larger than the above gap, an effect such as shrinkage when the adhesive is consolidated occurs, and a slight problem occurs in maintaining accuracy after the consolidation. When the gap is smaller than the gap, it is difficult to spread the adhesive evenly over the entire surface of the bonding surface.

As the adhesive to be filled in each bonding portion 101C, a thermosetting or time-curable inorganic adhesive is preferably used. By using such an adhesive, the adhesive can be bonded before adjusting the inclination angle of the polygon mirror. An agent can be filled and the adjustment can be performed before curing. Further, the adhesive has a longitudinal elastic modulus of 7000 kgf / m in a solidified state.
It is necessary that the thermal expansion coefficient be not less than m ^{2 and not} more than 2 × 10 ⁻⁵ / ° C. By satisfying the above conditions, the strength is maintained, deformation or the like due to stress during rotation of the polygon mirror is prevented, and there is no influence of a change in environmental temperature or the like. In the consolidated state, sufficient strength is guaranteed by satisfying the above conditions. In addition, the polygon mirror 101 and the radial shaft outer cylinder 1
It is desirable that the coefficient of longitudinal elasticity and the coefficient of thermal expansion of O. 02 are similar to the properties of the adhesive in a consolidated state, but the bonding surface of the bonding portion 101C is also substantially roughened such as ash. The fear of peeling or the like on the bonding surface is removed by enlarging.

In the above description, a polygonal mirror 101 having a small step in its inner diameter is engaged with a radial shaft outer cylinder 102 having a cylindrical outer shape, so that a fitting portion or an adhesive portion is provided between the two. However, in the present invention, the polygon mirror 101 having a cylindrical inner shape is engaged with the radial shaft outer cylinder 102 having a small step in the outer diameter. Thus, a configuration in which a fitting portion or an adhesive portion is formed between the two may be used.

[0019]

According to the present invention, the polygon mirror is bonded to the radial shaft outer cylinder using an adhesive,
It is now possible to remove the members that expand and contract due to temperature changes that were conventionally used, reducing the amount of change in dynamic balance due to temperature changes, reducing the amount of change in mirror flatness, reducing the number of parts and significantly increasing the number of assembly steps. An optical deflecting device and a method of assembling the optical deflecting device, which have been greatly reduced, have been provided.

Further, the gap between the polygon mirror and the radial shaft outer cylinder is provided with a different gap so that the adhesive is prevented from flowing out of the engagement, and the adhesive is effectively filled. It was decided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of an optical deflection device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram illustrating an example of an adjustment device of the light deflection device.

FIG. 3 is an explanatory view showing an example of assembling a polygon mirror and a radial shaft outer cylinder.

FIG. 4 is a perspective view of a writing optical system.

FIG. 5 is a cross-sectional configuration diagram of a conventional light deflecting device.

[Explanation of symbols]

 Reference Signs List 101 polygon mirror 101A mirror surface 101B fitting part 101C bonding part 101D loose part 101E inlet 102 radial shaft outer cylinder

Claims (5)

[Claims] An optical deflector that performs optical scanning by rotating a radial shaft outer cylinder having a polygon mirror fixed to a fixed radial shaft inner cylinder, wherein an engagement portion between the polygon mirror and the radial shaft outer cylinder is provided. Has an adhesive portion facing with a gap, an adhesive is filled in the gap between the adhesive portions, and the polygon mirror and the radial shaft outer cylinder are integrally fixed. apparatus. 2. The optical deflecting device according to claim 1, wherein the polygon mirror and the radial shaft outer cylinder have different gap portions for positioning and filling the adhesive at the bonding portion. 3. The adhesive has a longitudinal elastic modulus of 7000 kgf / mm ² or more and a thermal expansion coefficient of 2 × 10 ^-5 /
The optical deflector according to claim 1 or 2, wherein the temperature is lower than or equal to ° C. 4. An engagement portion between the polygon mirror and the radial shaft outer cylinder of an optical deflector for performing optical scanning by rotating a radial shaft outer cylinder having a polygon mirror fixed to the fixed radial shaft inner cylinder. Has an adhesive portion facing with a gap, and the polygon mirror in the engagement relationship is filled with an adhesive in the gap of the adhesive portion in a state where the inclination angle is adjusted with respect to the radial shaft outer cylinder. And fixing the polygon mirror and the radial shaft outer cylinder integrally with each other. 5. The adhesive has a longitudinal elastic modulus of 7000 kgf / mm ² or more and a thermal expansion coefficient of 2 × 10 ^-5 /
5. The method of assembling an optical deflecting device according to claim 4, wherein the temperature is less than or equal to 属 C.