JPH0279814A - Light deflector - Google Patents

Abstract

PURPOSE:To almost completely seal a rotary body and to suppress the infiltration of an unnecessary material into a frame by attaching a rotary polygon mirror, a magnet, a thrust direction bearing mechanism on the outer periphery of a rotary shaft and sealing hermetically and storing the rotary body pivoted around a dynamic pressure shaft supporting mechanism so as to be optionally rotated into a hollow formed by a frame. CONSTITUTION:A side frame 3 is bent like an L shape at a cross section so as to be interposed between the magnet 10 disposed on the outer periphery of a rotary shaft 6 and a stator H provided with a coil H opposed to the magnet 10 and the magnet 10, a thrust receiver 12 and the thrust bearing 13 are surrounded by the L-shaped frame. A stator fixing board 21 having an L-shaped cross section is fixed to the outside, i.e. a lower frame 2, of the bent part with L-shaped cross section and the stator 11 provided with the coil H and a base 15 mounting a hole element 16 are mounted to a stator fixing board 21 with an L-shaped cross section. Consequently, the rotary body R is spatially separated from the stator 11 and the rotary body R is completely and hermetically sealed and stored in the hollow formed by frame groups 1 to 3, the infiltration of unnecessary materials such as dust can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotating polygon mirror type optical deflector used in laser beam printers and the like.

(Conventional technology) A conventional example will be explained using FIGS. 2 to 4.

The housing a is composed of an upper frame 1 in which a glass member 20a is removably attached to an opening 20 in the side surface, a side frame 3 in which a lead wire extraction hole 19 is provided in the side surface, and a lower frame 2, and a land portion is provided inside. A shaft 4 having a herringbone groove 5 having a diameter of 5' on the outer periphery, and a shaft 4 on the outside of this shaft.
It accommodates a cylindrical hollow rotating shaft 6 that is rotatably fitted and a rotating body R made of members described later attached to the rotating shaft 6. The members to be described later include a polygon mirror 8 supported and fixed by the flange 7 of the rotating shaft 6, a magnet 10 on the outer periphery of the lower side of the flange 7 of the rotating shaft 6, a thrust receiver 12 disposed below the magnet 10, etc. , these members are rotatably provided together with the rotating body R. Further, a thrust bearing 13 is provided on the lower frame 2 below the thrust bearing. Furthermore, a stator 11 equipped with a coil H is disposed on the side frame 3 so as to face the magnet IO. Also, code 15 is magnet 1
This is a substrate that holds a Hall element 16 that detects the zero magnetic pole position and the rotational speed of the rotating shaft 6. Further, the lead wires 18 from the Hall element 16 and the coil H of the stator 11 are drawn out from a lead wire draw-out hole 19 provided in the side frame 3.

On the surface of the thrust bearing 13 facing the thrust bearing 12,
As shown in FIG. 4, a spiral groove 17 with a land 17' is cut.

First, when the coil H of the stator 11 is excited, the rotating shaft 6 rotates together with the polygon mirror 8 due to the electromagnetic action between the stator 11 and the magnet 10 provided on the outer periphery of the rotating shaft 6. According to this rotation, the herringbone groove 5 and the thrust bearing 13
The fluid f flowing into the spiral groove 17 generates dynamic pressure, and this pressure causes the rotating shaft 6 to levitate, while
The outer periphery of the shaft 4 is rotated smoothly in the direction of the arrow (FIGS. 3 and 4). In other words, the fluid f passing through the herringbone groove 5 is in the radial direction, and the fluid passing through the spiral groove 17 of the thrust bearing 13 is in the thrust direction, with the rotating shaft 6 forming a small gap with the shaft 4 in a non-contact state. There is a force at work that tries to support it.

(Problem to be Solved by the Invention) In the conventional configuration, since the lead wire extraction hole 19 is open between the outside and the stator 11 and the rotating body R,
While the rotating body is being driven, dust in the outside air may enter the inside of the device and enter the minute gap between the rotating shaft 6 and the shaft 4 or the minute gap between the thrust bearing 12 and the thrust bearing 13, causing seizure. Furthermore, there is a problem in that it adheres to the reflective surface of the rotating polygon mirror 8 and adversely affects the performance of the reflective surface.

In order to solve the above-mentioned problems, the present invention aims to provide a configuration in which a rotating body is almost completely sealed.

(Means for Solving the Problems) As a means for solving the problems described above, the present invention provides a rotating body and a stator of an optical deflector, which includes a rotating polygon mirror, an electric motor, a rotating shaft, and a dynamic pressure bearing portion that supports them. Provided is a structure characterized in that the rotating body is spatially separated from the optical deflector and the rotating body is hermetically housed in a cavity formed by the frame, thereby preventing unnecessary objects from entering the rotating body of the optical deflector. do.

(Function) According to the present invention, since the rotating body of the optical deflector is completely isolated from the outside, it will not be adversely affected by unnecessary substances that enter through the lead wire extraction hole, and the optical deflector Smooth rotation can be measured.

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

In addition, the members in the tree diagram with the same reference numerals as those in FIG. 2 are the same as those in the conventional example, and therefore their explanations will be omitted.

As shown in FIG. 1, the configuration of the present invention is such that the side frame 3 is cut in a cross-section so as to be interposed between a magnet 10 installed on the outer periphery of the rotating shaft 6 and a stator 11 equipped with an opposing coil H. This cross-section shaped frame 3I is curved in the shape of 3
Magnet 10, thrust receiver 12. The thrust bearing 13 is made to flex. A stator fixing base 21 having a slit-shaped cross section is provided on the lower frame 2 outside of the three curved portions having a slit-shaped cross section, and the stator 11 having the coil H and the board 15 to which the Hall element 16 is attached are fixed to the stator having a slit-shaped cross section. It is attached to the stand 21.

Further, a lead wire drawing hole 19 is provided on the side surface of the stator fixing base 21, and the lead wire 18 is drawn out from the coil H of the stator 11 through this hole 19.

Therefore, since the rotating body R and the stator 11 are spatially separated by the curved section 3 of the side frame 3, the rotating body R is completely formed in the cavity formed by the frame groups 1 and 3.2. It is stored sealed inside. Lead wire 1 as before
This prevents unnecessary objects such as garbage from entering through the drawer hole 19 of 8.

It is useful for improving the performance of the optical deflector by eliminating seizure of the hydrodynamic bearing 4 and adhesion of dust etc. to the reflective surface of the rotating polygon mirror 8 due to the intrusion of unnecessary objects into the optical deflector. Similarly, since the coil H of the stator 11 is drawn out from inside the frame, there are advantages such as a heat dissipation effect.

(Effects of the Invention) As described in detail above, according to the present invention, the rotating body R of the optical deflector is spatially separated from the stator and hermetically housed in the cavity formed by the frame. This has the effect of preventing unnecessary objects from entering the frame, preventing various problems caused by the entry of unnecessary objects, and helping to improve the performance of the optical deflector.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of an optical deflector according to the present invention. FIG. 2 is a sectional view of a conventional optical deflector. FIG. 3 is an enlarged plan view of the shaft for generating dynamic pressure. FIG. 4 is a plan view of the thrust bearing of the rotating body. 1... Upper frame, 2... Lower frame, 3... Side frame, 3... Cross-sectional curved part, 4... Shaft, 5... Herringbone groove, 6... ·Axis of rotation,
8... Polygon mirror, 10... Magnet, 11... Stator, 12... Thrust bearing, 13... Thrust bearing, 18... Lead wire, 19... Lead wire extraction hole. Applicant Copal Electronics Co., Ltd. Agent Patent Attorney Sakae Kobayashi Figure 1

Claims (1)

[Claims] 1. In an optical deflector that is rotatably supported in the radial and thrust directions by dynamic pressure, a rotating polygon mirror, a magnet, and a thrust direction bearing mechanism are attached to the outer periphery of the rotating shaft, and the dynamic pressure An optical deflector in which a rotating body rotatably supported by a shaft support mechanism is hermetically housed in a cavity formed by a frame. 2. The optical deflector according to claim 1, wherein the rotating body and the stator are spatially separated by an L-shaped curved section of the side frame.