JP2001042245A - Motor device for deflecting light - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the displacement of an optical scanning beam caused by the fluctuation of a refractive index in a motor device for deflecting light obtained by integrating the main body of a motor for driving a light deflecting element with a driving circuit. SOLUTION: In this motor device for deflecting the light obtained by integrating the motor 10 for driving the light deflecting element with its driving circuit 13 on a base plate 14, a void part 15 where a circuit element is not mounted is provided on the base plate 14 between the motor 10 and the circuit 13. Then, a hood 16 covering over the motor 10 comes in contact with the base plate 14 at the void part 15 and is provided so that the circuit 13 may be positioned on the outside of the hood 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor device for deflecting light, and more particularly to a motor device for deflecting light without causing displacement of an optical scanning beam due to fluctuation of a refractive index.

[0002]

2. Description of the Related Art As the demand for higher printing speed of a laser beam printer increases, the number of rotations (rotational speed) of a deflection motor for rotating and driving an optical deflecting element such as a polygon mirror tends to increase.

[0003] As the rotation speed of the deflection motor increases, various resistances increase, and the power consumption of the deflection motor increases.
As a result, there is a problem that the amount of heat generated from the motor increases.

Further, there is a problem that noise such as wind noise of the deflecting element and the rotor of the motor and driving noise of the motor are increased.

Further, since the reflecting surface on the deflecting element surface crosses the surrounding air at high speed, an air flow is generated at the edge of the reflecting surface (vortex is generated). Therefore, there is a problem that dust in the air adheres to the reflection surface.

In order to solve these problems, in order to solve the above-mentioned problem of an increase in the amount of heat generation, a heat radiating plate is attached, or a heat source is dispersed by separating a driving circuit and a motor body. .

Further, a hood is mounted around the motor in order to prevent noise from increasing and dust to adhere to the reflecting surface.

[0008]

However, separating the motor body from the drive board as described above not only increases the cost but also requires a space for disposing the drive board in a place different from the motor body. The device becomes larger. In addition, a harness connecting the motor body and the drive board is required, which is not preferable from the viewpoint of reliability.

Therefore, in a deflection motor which rotates at a high speed, the motor body and the driving substrate are integrated.

However, if the motor body is covered with the hood as described above in response to high-speed rotation, the drive circuit itself is also covered at the same time, so that the heat generated from the drive circuit is trapped inside. there were. In particular, if the heat is trapped, the temperature distribution in the hood is uneven and unstable, causing a fluctuation in the refractive index of the air in the hood, and as a result, the direction of the scanning beam is slightly displaced.
The image quality may be degraded.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide an optical deflection motor device in which a motor body for driving an optical deflection element and a drive circuit are integrated. An object of the present invention is to prevent displacement of an optical scanning beam due to refractive index fluctuation.

[0012]

According to a first aspect of the present invention, there is provided an optical deflecting motor apparatus comprising: a motor for driving an optical deflecting element and a driving circuit integrated on the substrate; A blank portion where no circuit element is mounted is provided on a substrate between the motor and the drive circuit,
A hood covering the motor contacts the substrate at the blank portion, and the hood is provided so that the drive circuit is located outside the hood.

According to another aspect of the present invention, there is provided an optical deflecting motor device comprising: an optical deflecting element driving motor and a driving circuit integrated with the substrate; However, the drive circuit is mounted on the opposite side of the substrate, and a hood for covering the motor is provided.

In the present invention, by integrating the motor for driving the light deflection element and its driving circuit, the cost can be reduced, and at the same time, the mounting space can be reduced and the reliability can be improved. In addition, even if a hood is attached to the motor for driving the light deflection element, the heat generated from the drive circuit does not stay inside the hood, so it is possible to reduce the fluctuation of the refractive index and improve the scanning characteristics. Obtainable.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a motor apparatus for deflecting light according to the present invention.

FIG. 1 is a plan view showing a state in which a laser beam scanning exposure apparatus having a motor device for light deflection according to one embodiment of the present invention is incorporated in a laser beam printer using an electrophotographic process. FIG. 3 is a side view of the light deflection motor device. In FIG. 1, illustration is omitted because there is no relation to the gist of the present invention except for the photosensitive drum and the laser beam scanning exposure apparatus in the electrophotographic process.

In FIG. 1, reference numeral 1 denotes a laser beam scanning and exposing device. A laser beam from a semiconductor laser 2 enters a reflecting surface of a rotary polygon mirror 4 rotating in the direction shown in FIG. The beam is deflected repeatedly within the laser beam, passes through lenses 5 and 6 constituting a scanning lens system, and is condensed on the surface of a photosensitive drum 7 in an electrophotographic process, thereby performing main scanning in the plane of the drawing. When the photosensitive drum 7 rotates around the central axis as shown in the figure, a sub-scan in the direction orthogonal to the main scanning is performed, and a two-dimensional electrostatic latent image is formed on the surface of the photosensitive drum 7. , Transfer and fixing, a print image is formed.

As shown in FIG. 2, the rotary polygon mirror 4 is mounted on a rotating part 12 of a motor 10, and
Is composed of the rotating part 12 and the fixed part 11. Motor 10
The rotary unit 12 has a magnet 20 and a rotor 19 that forms a magnetic circuit. A dynamic pressure bearing such as an air bearing or an oil fluid bearing is used for the bearing portion 21 that rotatably holds the rotating portion 12 so that high-speed rotation is possible. The fixed part 11 is provided with a stator coil 22 and the like that apply a driving force to the rotating part 12.

On the other hand, a drive circuit 13 for the motor 10
Is composed of a driver unit for controlling a drive current flowing through the stator coil of the fixed unit 11 of the motor 10, a control unit for switching the rotation speed of the rotating unit 12 and the excitation phase of the stator coil, and the like.

The motor 10 and the drive circuit 13 are mounted on one substrate 14. The substrate 14 is preferably made of a metal from the viewpoint of a heat radiation surface. The circuit wiring pattern may be formed directly on the substrate 14 or a separate circuit substrate may be provided on the substrate 14 (in FIG. 2, the circuit substrate is provided on the substrate 14). .

On the substrate 14, a blank portion 15 is provided between the motor 10 and the drive circuit 13. This part 15
Has no circuit elements mounted.

A hood 16 is provided so as to cover the entire motor 10, and the hood 16 is in close contact with the substrate 14 at a blank portion 15.

The hood 16 is provided with a window 17 through which a laser beam from the semiconductor laser 2 is incident and a window 18 through which a laser beam deflected by the rotary polygon mirror 4 is emitted. In order to keep the inside of the hood 16 sealed, a transparent plate such as glass is fitted into the windows 17 and 18. Although the hood 16 is provided so as to substantially seal the periphery of the rotary polygon mirror 4, the original object can be achieved without preventing the intrusion of dust even without a completely airtight structure.

As in this embodiment, in the motor device for light deflection in which the motor 10 and the drive circuit 13 are integrated on the substrate 14, circuit elements are provided on the substrate 14 between the motor 10 and the drive circuit 13. By providing a blank portion 15 that is not mounted, a hood 16 covering the motor 10 contacts the substrate 14 at the blank portion 15, and the hood 16 is provided so that the drive circuit 13 is located outside the hood 16, so that dust is reflected on the reflection surface. Adhesion can be prevented, noise can be reduced, and the optical scanning beam can be prevented from being displaced due to refractive index fluctuation due to heat generated from the drive circuit 13, so that good optical deflection scanning can be performed.

FIG. 3 is a side view of a motor device for light deflection according to another embodiment. In this embodiment, the substrate 14
A motor 10 and a rotary polygon mirror 4 rotated by the motor 10 are provided on the front side, and a drive circuit 13 is provided on the back side of the substrate 14 on the opposite side, and a hood 16 is provided on the front side. ing. In this case, since the motor 10 and the driving substrate 13 can be arranged on both surfaces of the substrate 14, there is an advantage that the size of the substrate 14 can be reduced as compared with the embodiment of FIG. Also in this case, the hood 16
Window 17 into which laser beam from semiconductor laser 2 is incident
And a window 18 through which the laser beam deflected by the rotary polygon mirror 4 is emitted. In order to keep the inside of the hood 16 sealed from the surrounding environment, the windows 17 and 18 have transparent plates such as glass. Is fitted (FIG. 1).

As a modification of the above embodiment, the hood 16
The scanning lens system may be configured by fitting a constituent lens (for example, lens 5) into the exit window 18 instead of the transparent plate.

Although the optical deflecting motor device of the present invention has been described based on the embodiments, the present invention is not limited to these embodiments, and various modifications can be made.

[0028]

As is clear from the above description, according to the optical deflecting motor device of the present invention, by integrating the optical deflecting element driving motor and its driving circuit, the cost can be reduced and Reduce the mounting space,
Reliability can also be increased. In addition, even if a hood is attached to the motor for driving the light deflection element, the heat generated from the drive circuit does not stay inside the hood, so it is possible to reduce the fluctuation of the refractive index and improve the scanning characteristics. Obtainable.

[Brief description of the drawings]

FIG. 1 is a plan view showing a state in which a laser beam scanning exposure apparatus having a motor device for light deflection according to one embodiment of the present invention is incorporated in a laser beam printer.

FIG. 2 is a side view of the optical deflection motor device shown in FIG. 1;

FIG. 3 is a side view of a light deflection motor device according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Laser beam scanning exposure apparatus 2 ... Semiconductor laser 3 ... Shaping lens 4 ... Rotating polygon mirror 5, 6 ... Lens which comprise a scanning lens system 7 ... Photosensitive drum 10 ... Motor 11 ... Fixed part 12 ... Rotating part 13 ... Drive circuit DESCRIPTION OF SYMBOLS 14 ... Substrate 15 ... Blank part 16 ... Hood 17 ... Incident window 18 ... Exit window 19 ... Rotor 20 ... Magnet 21 ... Bearing part 22 ... Stator coil

Continued on the front page F term (reference) 2H045 AA01 AA13 AA24 AA33 AA52 DA02 DA04 DA41 5H019 AA00 AA07 AA09 CC04 CC09 DD01 EE01 EE07 EE14 FF00 FF01 FF03

Claims (2)

[Claims] 1. An optical deflecting motor device in which an optical deflecting element driving motor and its driving circuit are integrated on a substrate, wherein a blank portion where no circuit element is mounted on the substrate between the motor and the driving circuit. Wherein the hood covering the motor is in contact with the substrate at the blank portion, and the hood is provided so that the drive circuit is located outside the hood. 2. A light deflecting motor device in which an optical deflecting element driving motor and its driving circuit are integrated with a substrate, wherein the motor is provided on one surface side of the substrate and the motor is provided on an opposite surface side of the substrate. A motor device for light deflection, comprising a drive circuit, and a hood for covering the motor.