JP3087549B2 - Rotating polygon mirror device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary polygon mirror used for laser scanning in a laser beam printer, a laser copying machine or the like.

[0002]

2. Description of the Related Art In recent years, polygon scanner motors have been widely used for scanning optical units such as laser beam printers and laser copiers. In particular, demands for high-speed printing and high-density printing have increased, and high-speed rotation and low-speed printing have been demanded. There is a need for a vibrating rotating polygon mirror device.

A conventional rotary polygon mirror device will be described below. FIG. 3 is a sectional view of a conventional polygon scanner motor having a rotating polygon mirror. In FIG. 3, 1
Is a rotation axis, 2 is a polygon mirror, 3 is a rotor magnet, 4 is a rotor yoke, 5 is a rotor boss, 6 is a mirror holding plate, 7 is a mirror fixing screw, 8 is a balance ring, 8
a is a groove for correcting the balance, 9 is a bracket, 10 is a screw for fixing the balance ring, and 12 is a bearing.

[0004] The operation of the rotary polygon mirror device configured as described above will be described below. First, reference numeral 1 denotes a rotating shaft which is shrink-fitted to the rotor boss 5 and 2 denotes a polygon mirror which is fixed to the screw 7 via the mirror pressing plate 6 on the rotor boss 5. The rotor magnet 3 and the rotor yoke 4 are fixed to a boss 5 to form a rotor. Reference numeral 8 denotes a balance ring fixed to the rotating shaft 1 with a screw 10.
The correction is performed by attaching a balance weight to the portion 8a.

[0005]

However, in the above-mentioned conventional construction, since the dimensions of the inner diameter of the polygon mirror and the outer diameter of the rotor boss are the same, it is necessary to process the outer diameter dimension portion where the dimensional accuracy of the fitting portion between the rotor boss and the polygon mirror is strict. At the time of assembling, the polygon mirror and the rotor boss may be entangled, and the surface tilting accuracy may be deteriorated. Since the balance ring is fixed to the rotating shaft with a screw, a tap is required and cutting is performed. In addition, the bottom of the bracket must be thickened to protect the balance ring, and a groove for fixing the screw is required, which requires a work process, and the motor cannot be downsized. Was.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and to provide a high-speed, low-vibration rotary polygon mirror device which has a simple structure and can be reduced in man-hours.

[0007]

SUMMARY OF THE INVENTION In order to attain this object, a rotary polygon mirror driving apparatus according to the present invention comprises a rotary shaft and a rotor shaft.
Rotor with rotor, rotor magnet, and rotor yoke
Equipped with a polygon mirror fixed via a mirror holding plate
The inner diameter of the mirror holding plate and the inner diameter of the polygon mirror
Rotary shaft having a step at the outer diameter portion of the rotor boss to be fitted
Opposite direction via rotor boss and bearing in surface mirror device
Press the balance ring stamped into the rotating shaft of
Or, it has an adhesively fixed configuration.

[0008]

According to this structure, when assembling the polygon mirror and the mirror holding plate, the mirror is prevented from being settled, the assembling property of the mirror is improved, and the tilting accuracy can be stabilized. In addition, the structure of the balance ring can be simplified, the number of steps can be reduced, and a rotating polygon mirror device that is advantageous for miniaturization with high speed and low vibration can be obtained.

[0009]

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

In FIG. 1, 1 is a rotation axis, 2 is a polygon mirror, 3 is a rotor magnet, 4 is a rotor yoke, 6
Is a mirror holding plate, 7 is a polygon mirror fixing screw, 9 is a bracket, 11 is a balance ring, 11a is a balance correcting groove, 12 is a bearing, and 13 is a rotor boss.

In FIG. 2, reference numeral 11b denotes a detent hole. The operation of the rotating polygon mirror of the polygon scanner motor configured as described above will be described with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a rotating shaft which is shrink-fitted and fixed to the rotor boss 13, and 2 denotes a polygon mirror which is fixed to the rotor boss 13 via a mirror holding plate 6 to a mirror fixing screw 7. The rotor is constituted by the rotating shaft 1 and the rotor magnet 3, and the rotor yoke 4 and the rotor boss 13. A step is provided at the outer diameter portion of the rotor boss where the inner diameter of the mirror and the inner diameter of the mirror holding plate are fitted, and the mirror thickness t
The rotor boss 13 is configured such that the mirror boss fitting portion changes from 1 / 3t to t. Reference numeral 11 denotes a balance ring which is stamped and pressed or bonded and fixed to the rotating shaft 1 in the opposite direction via the rotor boss 13 and the bearing 12 so as to be inside the bracket 9. A balance weight is attached to the balance ring 11a to correct the balance.

In FIG. 2, the balance ring has a structure having a detent hole 11b when the polygon mirror 2 is fixed.

[0014]

As described above, according to the present invention, a step is provided in the outer portion of the rotor boss where the inner diameter of the polygon mirror and the inner diameter of the mirror holding plate are fitted, and the mirror boss fitting portion is 1 / 3t to t with respect to the mirror thickness t. By configuring the rotor boss such that the mirror boss and the like are prevented, the accuracy of the surface tilt is stabilized. In addition, the structure of the balance ring can be simplified by press-fitting or adhesively fixing the punched balance ring to the rotating shaft in the opposite direction via the rotor boss and the bearing, and the mirror ring is provided by providing a detent hole in the balance ring. The present invention can improve the assemblability, and realize an excellent rotary polygon mirror driving device having a simple structure, high-speed rotation and low vibration.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotary polygon mirror driving device according to the present invention.

FIG. 2 is a diagram showing a balance ring according to the present invention.

FIG. 3 is a sectional view of a conventional rotary polygon mirror driving device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotation axis 2 Polygon mirror 3 Rotor magnet 4 Rotor yoke 6 Mirror holding plate 7 Polygon mirror fixing screw 8, 11 Balance ring 8a, 11a Balance correction groove 9 Bracket 10 Balance ring fixing screw 11b Non-rotating hole 12 Bearing 13 Rotor boss

Continuation of the front page (56) References JP-A-4-33554 (JP, A) JP-A-4-361219 (JP, A) JP-A-3-122418 (JP, U) JP-A-4-20014 (JP) , U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G02B 26/10

Claims (1)

(57) [Claims] 1. A rotary shaft and a rotor boss, a rotor magnet, said rotor comprising a polygon mirror which is fixed via the mirror holding plate to a rotor having a rotor yoke, said polygon mirror inside diameter and said mirror retainer plate inside diameter is fitted < in rotating polygon mirror apparatus provided with a step on br /> boss outer diameter, b
Stamping on the rotating shaft in the opposite direction via
A rotating polygon mirror device in which the engineered balance ring is press-fitted or bonded and fixed .