JPH0552813U - Rotating polygon mirror holding mechanism of optical deflector - Google Patents

Abstract

(57) [Summary] [Object] To provide a mechanism for fixing a rotary polygon mirror in an optical deflector, which is easy to assemble, low in cost, and uniform in pressure. [Structure] The rotary polygon mirror 14 is inserted and mounted on a hub 16. The hub 16 includes an annular elastic body 4 and a rotary polygon mirror 14.
There is a chamfer 2 provided on the outer circumference of the hub cylindrical portion 16b in order to generate a pressure for pressing. This hub 16 has its outer diameter φ
An elastic body 4 having an inner diameter slightly smaller than d is inserted from above, and a uniform pressing force is applied to the rotary polygon mirror 14 by the repulsive force of the annular elastic body 4 to fix the rotary polygon mirror 14 to the hub 16.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a rotary polygon mirror holding mechanism for a rotary polygon mirror type optical deflector used in a laser beam printer or the like.

[0002]

[Prior Art]

 Conventionally, there have been various mechanisms for fixing the rotary polygon mirror of the optical deflector. The first configuration is shown in FIG. 2, in which the rotary polygon mirror 14 fitted to the outer periphery of the tubular portion 16a of the hub 16 is placed on the protruding arm portion 16a of the hub 16 and the rotary polygon mirror 14 In order to fix the hub to the hub 16, a donut-shaped elastic body 24 arranged on the rotary polygon mirror is pressed by a leaf spring 26 having a U-shaped cross section provided so as to cover the opening of the cylindrical portion 16b of the hub 16. Was there. In this case, there is also a method of engaging the protrusion of the leaf spring 26 in the groove formed in the hub outer cylinder portion 16a. Although the rotary polygon mirror 14 fixed to the hub 16 in this way is not shown, when the hub 16 rotates together with the rotary polygon mirror 14 due to the rotation of the rotor, the hub 16 is supported by the bearing 20 provided on the fixed shaft 18. To rotate around the fixed shaft 18. As described above, when the rotary polygon mirror 14 is rotated, a beam from the outside is incident on and reflected by the mirror surface 14a to be scanned. Reference numeral 22 is a retaining ring for locking the bearing 20 provided on the head of the fixed shaft 18. The second configuration is as shown in FIG. 3, in which the donut-shaped elastic body 24 is pressed against the upper surface of the rotary polygon mirror 14 by a leaf spring 28 having a U-shaped cross section, and the leaf spring 28 is pushed into the tubular portion of the hub 16. It is locked by a retaining ring 30 attached to 16b. The third configuration is as shown in FIG. 4, and therefore, the rotary polygon mirror 14 disposed between the outer peripheral surface 16c of the hub 16 fixed to the outer periphery of the rotary shaft 19 and the horizontal projecting arm 16a is attached to the hub. It is pressed by a leaf spring 32 arranged so as to spread on the upper surface 16d of 16, and the leaf spring 32 is locked by a retaining ring 34 provided on the upper outer peripheral portion of the fixed shaft 18.

[0003]

[Problems to be solved by the device]

 The rotary polygon mirror holding mechanism of the above-mentioned conventional example has the following problems. That is, in the configuration shown in FIGS. 2 and 4, two parts of a donut-shaped or annular member and a leaf spring are used. In the configuration of FIG. 3, three parts of a donut-shaped or annular elastic body, a leaf spring and a retaining ring are used. 4 must be used, and in the configuration of FIG. 4, since the leaf spring has a special shape of a fin, the pressing force of this leaf spring does not act uniformly on the rotating polygon mirror, resulting in a rotation. It becomes difficult to keep the polygon mirror horizontal, and distortion occurs on its reflection surface. Similarly to the configuration shown in FIG. 4, the leaf spring of FIG. 2 and the leaf spring of FIG. 3 do not apply a pressing force evenly on the rotary polygonal mirror of the long arm portion, so that the reflecting surface thereof is distorted.

[0004]

[Means for Solving the Problems]

 Therefore, in the present invention, the object is to solve the above-mentioned problems, and means for achieving this object will be disclosed below. The rotary polygon mirror 14 mounted on the hub 16 is rotatable together with the hub 16, and in the optical deflector for scanning the beam reflected by the mirror surface 14a of the rotary polygon mirror 14, chamfering is performed on the outer circumference of the hub cylindrical portion 16b. When the rotary polygon mirror 14 is mounted on the hub 16, the annular elastic body 4 is pushed into the chamfer 2 to fix the rotary polygon mirror 14 to the hub 16. It is a pressing mechanism that pushes the annular elastic body 2 into the chamfer 2 in a deformed state, fixes the rotary polygon mirror 14 to the hub 16 by the repulsive force of the annular elastic body 2, and changes the diameter of the chamfer 2 from the annular elastic body 4. Is also slightly larger.

[0005]

[Action]

 When the rotary polygon mirror is mounted on the hub, the annular elasticity is crushed, deformed and pushed into the chamfer provided on the outer periphery of the hub tubular portion, and the elastic repulsive force fixes the rotary polygon mirror to the hub.

[0006]

【Example】

 An embodiment of a rotary polygon mirror holding mechanism according to the present invention will be described below with reference to the accompanying drawings. In FIG. 1, the ring-shaped elastic body 4 is used as a member for inserting the rotary polygon mirror 14 into the outer periphery of the cylindrical body 16b of the hub 16 from above and pressing and fixing it on the hub 16 so that it does not move. In the present embodiment, the chamfer 2 is formed on the outer peripheral portion 16b of the hub 16 into which the rotary polyhedron 14 is fitted, without using the leaf spring, the retaining ring or the like of the conventional example. When the rotary polygon mirror 14 is inserted into the tubular portion 16b of the hub 16 from above and the rotary polygon mirror 14 is mounted on the horizontally projecting arm 16a of the hub 16, pressure is applied vertically to the annular elastic body 4. In addition, when the deformed portion of the annular elastic body 4 is pushed into the chamfer 2 from the outside by deforming it into an elliptical shape, the compressed annular elastic body 4 exerts a repulsive elastic force that tends to return to its original shape. Since pressure is generated to press the rotary polygon mirror 14 in the direction of the arrow a shown in the figure, the rotary polygon mirror 14 is fixed between the horizontally projecting arm 16a of the hub 16 and the outer cylindrical portion 16b so as not to move. Therefore, the inner diameter of the annular elastic body 4 is made slightly smaller than the inner diameter φd of the chamfered portion of the hub 16. Therefore, the annular elastic body 4 adheres to the chamfer 2 provided on the outer periphery of the hub outer cylindrical portion 16b and is in close contact therewith, so that the rotary polygon mirror 14 is firmly fixed to the hub 16. In this way, when the annular elastic body 4 is deformed and pushed into the hub outer cylindrical portion 16b into the chamfered portion 2, the repulsive elastic force of the annular elastic body 4 causes the rotary polygon mirror 14 to be uniformly pressed so that the horizontally projecting arms 16a of the hub 16 can be prevented. The hub outer tube portion 16b can be fixed so as not to move.

[0007]

【effect】

 In the present invention, the pressing component is formed by pressing one annular elastic member into the chamfer formed on the outer periphery of the hub tubular portion in a deformed state, and utilizing the repulsive force caused by the deformation of the annular elastic body. The rotating polygon mirror can be easily placed and fixed on the hub so that it does not move, and the pressing force of the annular elastic body on the rotating polygon mirror can be held evenly, so that the reflecting surface is not easily rotated when the rotating polygon mirror rotates. Since it can prevent the occurrence of distortion and distortion, it helps improve the performance of the optical deflector and uses a small number of parts, which reduces the manufacturing cost accordingly.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating a holding mechanism of a rotary polygon mirror of an optical deflector according to the present invention.

FIG. 2 is a schematic cross-sectional view of a pressing mechanism of a conventional rotary polygon mirror.

FIG. 3 is a schematic cross-sectional view of a pressing mechanism for another conventional rotary polygon mirror.

FIG. 4 is a schematic cross-sectional view of a pressing mechanism of another conventional rotary polygon mirror.

[Explanation of symbols]

 2 chamfer 4 annular elastic body 14 rotating polygon mirror 14a mirror surface 16 hub 16a hub horizontal protruding arm 16b hub tubular portion 18 shaft 19 shaft 20 bearing

Claims (3)

[Scope of utility model registration request] 1. An optical deflector configured to rotate a rotary polygon mirror mounted on a hub together with the hub so as to enter a mirror surface of the rotary polygon mirror and scan a reflected beam, wherein a chamfer is formed on an outer circumference of a hub cylindrical portion. When the rotary polygon mirror is mounted on the hub, an annular elastic body is pushed into the chamfer to fix the rotary polygon mirror to the hub. 2. The pressing mechanism for a rotary polygon mirror of an optical deflector according to claim 1, wherein the deformed annular elastic body is pushed into the chamfer, and the rotary polygon mirror is fixed to the hub by the repulsive force of the annular elastic body. 3. A holding mechanism for a rotary polygon mirror of an optical deflector, wherein a diameter of a chamfer formed on a hub outer cylinder portion is formed slightly larger than a diameter of an annular elastic body.