JPH04112218U - optical scanning device - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a thin optical scanning device with high precision in handling polygon mirrors. [Structure] The surface 8a facing the substrate 1 of the polygon mirror 8, which also serves as the rotor of the flat brushless motor, is the dynamic pressure surface.
A polygon mirror is supported by a ball bearing 9 on a shaft 2 fixed to a substrate, and when the polygon mirror rotates at high speed, the polygon mirror is lifted from the substrate by the amount of play in the axial direction of the ball bearing to maintain a constant dynamic pressure gap. let

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea uses the rotor of a flat brushless motor as a polygon mirror for deflecting light beams. This invention relates to an optical scanning device used as an optical scanning device.

0002

[Conventional technology]

Light beam deflection using the rotor of a flat brushless motor as a polygon mirror (hereinafter referred to as polygon mirror motor for convenience), which has dynamic pressure generating grooves. In addition to supporting the rotor with a shaft, a base plate (fixed thrust bearing member ) is known in which dynamic pressure generating grooves are formed on the rotor surface facing the Publication No. 2-59715).

0003

[Problem that the idea aims to solve]

In a conventional polygon mirror motor, the rotor rotates in both its thrust and radial directions. Since both are held by dynamic pressure support means having dynamic pressure generating grooves, polygon In order to ensure the precision of the rollers, both component precision and assembly precision must be high. In addition, in order to make the polygon mirror motor thinner, the rotor support shaft must be made thinner. However, if you do so, the radial direction dynamic pressure bearing may be shortened. There is a problem that the rigidity (holding force) is insufficient under air dynamic pressure.

0004

[Means to solve the problem]

This idea is based on a polygon mirror with a rotor magnet on the surface facing the drive coil. -, a substrate on which a shaft supporting the polygon mirror is embedded, and the polygon mirror Place the above polygon with the surface opposite to the above surface in close proximity to or lightly touching the above board. The upper A light beam deflector with dynamic pressure generation grooves on the opposite side or at least one side of the substrate. It is characterized by having.

[0005]

[Effect]

The point floats up due to the thrust dynamic pressure generated by the high speed rotation of the polygon mirror. The polygon mirror is supported by ball bearings and the base of the substrate and polygon mirror. A constant dynamic pressure gap is maintained between the base and the base surface.

[0006]

【Example】

Reference numeral 1 indicates the board of the polygon mirror motor, and in the center of this board 1 there is a motor. A shaft 2 supporting the rotor of the motor is fixedly planted. In addition, the top plate 3 is columnar on the substrate 1. It is fixed parallel to the substrate 1 with a headed screw 5 via a spacing member 4 . Inside top plate 3 A printed circuit board 7 having a drive coil 6 is attached to the side using fixing means such as screws. It is being

[0007] A polygon mirror 8 that also serves as the rotor of the motor is installed near the top of the shaft 2. It is rotatably supported by a ball bearing 9. polygon mirror A rotor magnet 10 is fixed together with a yoke 11 on the surface facing the drive coil 6 of 8. has been established. The surface 8a of the polygon mirror 8 on the substrate 1 side is close to or lightly in contact with the substrate 1. and on the surface, as shown in FIG. 3, extending outward from the center of the polygon mirror, and a dynamic pressure generating groove that is curved and inclined in a direction that tilts toward the rotation direction a of the polygon mirror. 12 are formed.

[0008] When the polygon mirror 8 rotates around the axis 2 at high speed, the lower surface 8 of the polygon mirror 8 Due to the dynamic pressure created by the dynamic pressure generation groove between a and the top surface of the substrate 1, the polygon mirror 8 is It floats up by the amount of play in the axial direction of the ball bearing 9, and the space between the polygon mirror and the substrate A certain dynamic pressure gap is created between the polygon mirrors and the ball bearings. remains constant during high-speed rotation.

[0009] Similar to the substrate 1, the relatively strong top plate 3 is placed with this side down, i.e. as shown in FIG. Required when the polygon mirror motor is used in an inverted position and therefore , when used with the substrate 1 facing downward as shown in Fig. 1, the top plate 3 is not used. A printed circuit board 7 is fixed to the substrate 1 via the spacing member 4.

0010 The dynamic pressure generating groove may be formed on the surface of the substrate 1 facing the polygon mirror, or may be provided on both the substrate 1 and the polygon mirror.

[0011]

[Effect of the idea]

The reference surface facing the polygon mirror substrate is used as the dynamic pressure surface to ensure a dynamic pressure gap. This invention uses a single ball bearing to maintain the alignment in both the radial and radial directions. According to An optical scanning device equipped with a thin polygon mirror motor with high precision and trouble-free operation can be obtained. It will be done.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an optical scanning device showing an embodiment of the present invention.

FIG. 2 is a plan view of the same as above.

FIG. 3 is a plan view showing an example of dynamic pressure generating grooves provided in a polygon mirror.

[Explanation of symbols]

1 board 2 axes 6 Drive coil 8 Polygon mirror 9 Ball bearing 10 Rotor magnet

Claims (1)

[Scope of utility model registration request] 1. A polygon mirror having a rotor magnet on a surface facing a drive coil, a substrate having a shaft for supporting the polygon mirror implanted therein, and a surface of the polygon mirror opposite to the surface located close to the substrate. or a light beam deflector comprising one ball bearing that rotatably supports the polygon mirror on the shaft in a state of light contact, and a dynamic pressure generating groove is provided on at least one of the opposite surface or the substrate. An optical scanning device having: