JPH0668579B2 - Optical scanning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device, and more particularly, a specular body having a light reflecting surface formed on its outer peripheral surface is rotated by a motor to be scanned with a reflected light beam. The present invention relates to an optical scanning device of the type that scans a surface.

BACKGROUND OF THE INVENTION An optical scanning device used in a laser beam printer, an image reading device, or the like is configured so that a light beam generated by a light source is deflected by a polygon mirror that is driven by a motor and is rotated to fix a surface to be scanned. To be done.

And in order to make this type of optical scanning device small, a combination of a polygon mirror and a flat motor is used.
It is disclosed in JP-A-59-197010. The optical scanning device shown in FIG. 2 of this publication is thin because the open reflection surface is formed on the outer peripheral surface of the permanent magnet that constitutes the rotor of the motor, but it projects on both sides of the permanent magnet. Since the end of the rotary shaft is supported by the bearing provided on the housing member and the bearing provided on the cover member, in order to prevent the light reflection surface from being tilted, the accuracy of fitting the housing member and the cover member should be improved and The dimensional accuracy of the member must be increased, and the number of highly accurate processed parts increases. Also, since the light reflecting surface is magnetic, it is highly possible that if cutting powder or polishing powder remains on the component, it will magnetically adhere to the light reflecting surface and disturb the reflected light. Great care must be taken to avoid residue formation. Furthermore, if the lubricating oil leaks from the bearing on the cover member side, the light reflecting surface underneath it will be contaminated, so it is necessary to take measures to prevent the leakage.

Further, in the one shown in FIG. 4 of the same publication, since the shaft protruding only on one side of the polygon mirror is supported by one bearing, the slight reflection of this bearing is enlarged to the light reflecting surface. This causes a large surface runout, and therefore extremely high precision is required for the bearing. In addition, it is necessary to take measures to prevent the adverse effect of the magnetism of the light reflecting surface.

[Object of the Invention]

It is an object of the present invention to provide an optical scanning device of this type, which can ensure the accuracy of the light-reflecting surface with a relatively small size and which is less susceptible to contamination of the light-reflecting surface. .

[Outline of Invention]

The present invention is an optical scanning device in which a flat motor having a light-reflecting surface formed on its outer periphery is driven by a flat motor, wherein the flat motor has a rotor support shaft and a flat bottomed cylindrical shape. The mirror body includes a housing, a flat armature coil fixed along the bottom surface of the housing, and a permanent magnet fixed to the mirror body so as to face the armature coil in the axial direction of the rotor support shaft. Is made of a non-magnetic material and has a shaft hole that penetrates the mirror body at the center, and bearing fitting surfaces are formed at both ends of the shaft hole. Each of the bearings is installed, and the rotor support shaft is press-fitted and fixed to the inner circumference of this bearing, and both bearings are turned outward by a preload spring inserted in the space between the inner circumference of the shaft hole and the outer circumference of the rotor support shaft. Press and insert one end of the rotor support shaft into the center of the bottom of the housing. With a screw that is inserted from the outer surface and screwed into the rotor support shaft, the rotor support shaft is pushed into the back of the housing bottom to press the bearing located on the bottom of the housing against the housing bottom, It is characterized in that a cover for closing the opening end of the shaft hole on the opposite side of is attached.

Example of Invention

 An embodiment of the present invention will be described with reference to FIG.

A resin base 2 is attached to the bottom portion 1a of the cylindrical housing 1 having a bottom.
On the lower surface of the resin base 2 attached to the flat armature coil 3 is fixed. The stator yoke 4 is provided on the bottom portion 1a so as to face the armature coil 3 and constitutes a stator magnetic path. The rotor support shaft 5 is fixed to the bottom portion 1 a by a set screw 6 and projects into the housing 1. At the center of the mirror surface body 7 made of a non-magnetic high-luminance material, there is a shaft hole 7a penetrating this, and the mirror surface body 7 is fitted into the bearing fitting surfaces 7b and 7c at both ends of the shaft hole 7a. It is rotatably mounted on the rotor support shaft 5 by bearings 9a, 9b preloaded by 8. The influence of rattling of the bearings 9a and 9b on the deflection of the mirror body 7 becomes smaller as the distance between the bearings 9a and 9b increases. Therefore, the bearing fitting surface 7c into which the lower bearing 9b is fitted projects downward in the central portion of the mirror body 7 and is formed in the cylindrical projection 7d extending through the central hole 2a of the resin base 2. And the bearing 9b becomes the rotor support shaft 5
It is supposed to be located at the base of. The cover 10 closes the upper open end of the shaft hole 7a to prevent the lubricating oil from scattering from the bearing 8a.

A flat magnet 12 is attached to the lower surface of the mirror body 7 via a rotor yoke 11 by adhesion. The magnet 12 constitutes a flat motor facing the armature coil 3, and the position of the magnetic pole of the magnet 12 is detected by the Hall element 13 provided on the resin base 2 and connected by the lead wire 14. A control circuit (not shown) controls the current of the armature coil 3.

The outer periphery of the mirror body 7 is cut into a certain number of angles (for example, regular octagon), and a protective film is further formed on the surface of the mirror body 7 to form a mirror-like light reflecting surface 7e. The light reflecting surface 7e is arranged outside the bearings 9a and 9b in order to minimize adverse effects due to thermal expansion, rattling of the bearings 9a and 9b, and a fitting error.

A light beam entrance / exit window 1d is formed in the cylindrical portion 1c of the housing 1 so as to face the light reflecting surface 7e, and the opening end of the cylindrical portion 1c is closed by a cover 15 for safety and dust prevention.

〔The invention's effect〕

As described above, the present invention is an optical scanning device that drives a mirror-like body having a light-reflecting surface on the outer periphery by a flat motor, the flat motor being formed in a flat shape with the rotor support shaft. A bottomed cylindrical housing, a flat armature coil fixed along the bottom surface of the housing, and a permanent mirror fixed to the mirror body so as to face the armature coil in the axial direction of the rotor support shaft. A magnet is provided, and the specular body is formed of a non-magnetic material, and a shaft hole penetrating the specular body is formed at the center,
Bearing mating surfaces are formed at both ends of this shaft hole, and bearings whose outer circumferences are press-fitted and fixed to both bearing fitting surfaces are provided.The rotor support shaft is press-fitted and fixed to the inner circumference of this bearing. , Both bearings are pressed outward by a preload spring inserted in the space between the inner circumference of the shaft hole and the outer circumference of the rotor support shaft, and one end of the rotor support shaft is inserted in the center of the bottom of the housing. From the screw that is inserted into the rotor support shaft and screwed into the rotor support shaft, the rotor support shaft is pushed toward the inner side of the housing bottom to press the bearing arranged on the bottom side of the housing against the housing bottom,
The optical scanning device is equipped with a cover that closes the opening end of the shaft hole on the opposite side of the housing bottom. According to this configuration,
It has the following advantages.

(1). Fit the bearings on the bearing mating surfaces formed on both ends of the shaft hole, press both bearings outward with a preload spring, and load the rotor support shaft with a screw to secure the bearing on the bottom side of the housing. Since the mirror body is pressed, the movement of the mirror support body in the axial direction of the rotor support shaft does not occur, and the mirror body does not rotate.

(2). The preload spring is inserted in the space formed between the shaft hole and the rotor support shaft, and it is possible to provide a compact optical scanning device having an extremely low length as compared with one in which the preload spring is provided outside the bearing.

(3). Since the cover that closes the outer opening end of the shaft hole of the mirror surface body and the opening end of the housing is provided, the light reflecting surface is not contaminated by the bearing lubricating oil and the safety is improved.

[Brief description of drawings]

The drawing is a vertical side view of the optical scanning device according to the present invention. 1 ... Housing, 1a ... Bottom part, 3 ... Armature coil, 5 ...
Rotor support shaft, 7 ... Mirror body, 7a ... Shaft hole, 7b, 7c ...
Bearing fitting surface, 7e ... Light reflecting surface, 8 ... Preload spring, 9a, 9
b ... Bearing, 10, 15 ... Cover, 12 ... Magnet.

Claims (1)

[Claims] 1. An optical scanning device for driving a mirror-shaped body having a light-reflecting surface on its outer periphery by a flat motor, wherein the flat motor has a rotor support shaft and a flat bottomed cylindrical shape. A housing, a flat armature coil fixed along the bottom surface of the housing, and a permanent magnet fixed to the mirror body facing the armature coil in the axial direction of the rotor support shaft. The body is made of non-magnetic material, and a shaft hole that penetrates the mirror surface body is formed in the center, and bearing fitting surfaces are formed at both ends of the shaft hole. Each fixed bearing is installed, the rotor support shaft is press-fitted and fixed to the inner circumference of this bearing, and both bearings are turned outward by a preload spring inserted in the space between the inner circumference of the shaft hole and the outer circumference of the rotor support shaft. , Insert one end of the rotor support shaft into the center of the bottom of the housing, With a screw that is inserted from the outer surface of the bottom part and screwed into the rotor support shaft, the rotor support shaft is pushed into the inner side of the housing bottom part to press the bearing arranged on the bottom side of the housing to the housing bottom part. Then, by pushing the rotor support shaft into the inner side of the bottom of the housing, the bearing arranged on the bottom of the housing is pressed against the bottom of the housing, and a cover that closes the opening end of the shaft hole on the side opposite to the bottom of the housing is attached. An optical scanning device characterized by being attached.