JPH06289314A - Light deflector - Google Patents

Abstract

PURPOSE:To reduce wind whisle caused by air flowing out from the cover of a rotary polygon mirror. CONSTITUTION:The cover 2 covering the rotary polygon mirror 1 is provided with a window 6 on the cylindrical wall 2a surrounding the outside circumferential surface of the mirror 1. Then, the outside cirumferential surface of the mirror 1 is irradiated with a laser light beam L1 emitted from a light source 3 and passed through the window 6. By it, the deflection and the scanning of the beam L1 are executed and the image thereof is formed on a photosensitive drum through an image forming lens system 5. Since the cover 2 is provided with a guide piece 7 projecting along the side surface 51a of the spherical lens 5a of the lens system 5 and forming a flow passage 8, the air flowing out from the window 6 is decelerated while it is passed through the passage 8 and the large wind whisle is not caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflector for deflecting and scanning a laser beam or the like at a high speed in a laser printer or the like.

[0002]

2. Description of the Related Art Optical deflectors for laser printers, laser facsimiles and the like have been particularly accelerated in recent years, and rotary polygon mirrors used for these deflectors rotate at high speeds of 10,000 or more revolutions per minute. When the rotary polygon mirror is rotated at such a high speed, the wind noise during rotation is increased and a large noise is generated. Therefore, the periphery of the rotary polygon mirror is covered with a substantially cylindrical cover.

FIG. 4 illustrates the entire structure of a general optical deflector, which is a laser beam L generated from a laser oscillator 110.
0 is focused into a predetermined beam shape by the cylindrical lens 103, then deflected and scanned by the rotary polygon mirror 101, passes through the imaging lens system 105, and passes through the photosensitive drum 107.
Image on top. A part of the laser light reflected by the rotating polygon mirror 101 is reflected by the reflecting mirror 108 to the optical fiber 1.
09, and is converted into a scan start signal.

FIG. 3 shows the rotary polygon mirror 101 and its drive unit. The drive unit of the rotary polygon mirror 101 is a rotary shaft 111.
And the rotor magnet 112 integrally connected to the
The rotary polygon mirror 1 includes a stator coil 114 that is integral with a bearing device 113 that supports the rotary shaft 111, and a circuit board 115 that supplies a drive current to the stator coil 114.
01 is a corrugated washer 116a and a flat washer 116b
A pressing mechanism 116 including a stopper ring 116c presses the flange member 111a, which is integrated with the rotating shaft 111, and thereby is integrated with the rotating shaft 111. The rotary polygon mirror 101 is covered with a substantially cylindrical cover 102, which restricts the flow of air accompanying the rotation of the rotary polygon mirror 101, reduces wind noise, and reduces wind noise to the outside. Prevent it from leaking. The cover 10
The second cylindrical portion 102a has a window 10 through which laser light passes.
6 is provided.

[0005]

However, according to the above-mentioned prior art, when the air flowing inside the cover due to the high speed rotation of the rotary polygon mirror flows out through the window for entering and exiting the laser light. In addition, a large wind noise is generated due to friction with the edge of the window or the lens adjacent to the window, which causes noise.

The present invention has been made in view of the above-mentioned problems of the prior art, and a wind noise when the air flowing along with the high speed rotation of the rotary polygon mirror inside the cover flows out from the cover. It is an object of the present invention to provide an optical deflector capable of reducing the above.

[0007]

In order to achieve the above object, an optical deflector according to the present invention comprises a rotary polygon mirror for deflecting and scanning the illumination light applied to the outer peripheral surface, and a cylindrical portion covering the outer peripheral surface. An optical deflector having a cover, an opening through which the illumination light passes is provided in a cylindrical portion of the cover, and the opening faces one surface of an object provided outside the cover. The cover has a guide member protruding along another surface of the object.

It is sufficient that the object and the guide member are separated by 1 mm or more.

[0009]

The air in the cover flows at a high speed as the rotary polygon mirror rotates at a high speed, and flows out through the opening of the cover. The air flowing out from the opening flows along the one surface of the object facing it into the flow path formed between the other surface of the object and the guide member, and loses its flow velocity while passing through the flow path. Slow down. The air flowing out from the opening smoothly flows along the surface of the object, is decelerated, and is then discharged to the outside, so that wind noise due to friction with the object or the guide member or a vortex can be reduced.

[0010]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a partial schematic cross-sectional view showing the main part of one embodiment. The optical deflector of this embodiment is a rotary polygon mirror 1 which is rotated in the direction of arrow A by a drive mechanism (not shown).
And a substantially cylindrical cover 2 that covers the same, and the cover 2 includes a cylindrical wall 2a that is a cylindrical portion and a disc-shaped top wall 2b.
The laser beam L1 (shown in FIG. 2) is emitted from the light source 3 to the rotary polygon mirror 1 via the collimator lens 4, is deflected and scanned by this, and is coupled to a photosensitive drum (not shown) via the imaging lens system 5. Image. The cover 2 has a window 6 which is an opening for passing the laser light which is irradiated on the rotary polygon mirror 1 and reflected by the rotary polygon mirror 1 in this way. The imaging lens system 5 has a spherical lens 5a, which is an object adjacent to the rotary polygon mirror 1, and a toric lens 5b provided behind it.

The window 6 is a rectangular opening elongated in the circumferential direction of the rotary polygonal mirror 1, and among the side edges 6a and 6b thereof, the side edge 6b on the downstream side in the rotation direction of the rotary polygonal mirror 1 is A guide piece 7 which is a guide member protruding outward from the cylindrical wall 2a of the cover 2.
The guide piece 7 extends substantially radially outward of the cylindrical wall 2a of the cover 2 along the side surface 51a of the spherical lens 5a of the imaging lens system 5, and the side surface 51a of the spherical lens 5a.
And a passage 8 having a width of 1 mm or more extending from the window 6 to the outside of the cylindrical wall 2a of the cover 2 in the radial direction. The surface 52a of the spherical lens 5a facing the window 6 of the cover 2 is also arranged so as to be separated from the cylindrical wall 2a of the cover 2 by 1 mm or more.

When the rotary polygon mirror 1 rotates at a high speed in the direction of arrow A, an air stream flowing at a high speed in the rotation direction is generated in the cover 2 as the rotary polygon mirror 1 rotates. The part swirls in the rotation direction and flows out of the cover 2 through the window 6. Most of the air flowing out of the cover 2 through the window 6 swirls in the rotation direction of the rotary polygon mirror 1 along the surface 52a of the spherical lens 5a facing the cover 2 as shown by an arrow W1 and flows. It is released to the surrounding atmosphere through the passage 8. The air thus discharged gradually loses a part of its flow velocity while passing through the flow path 8 and is decelerated, and there is no possibility of generating a large wind noise due to vortices and friction.

Further, as shown in FIG. 2, in order to prevent a part of the air passing through the flow path 8 from leaking out from each side edge 7a of the guide piece 7 and generating noise due to friction and vortex, each side edge 7a is prevented. It is preferable to provide an eaves 7b protruding in the width direction of the flow path 8.

[0015]

Since the present invention is configured as described above, it has the following effects.

Wind noise caused by air flowing out from the cover of the rotary polygon mirror can be reduced. As a result, an optical deflector with less noise can be realized.

[Brief description of drawings]

FIG. 1 is a partial schematic cross-sectional view showing a main part of one embodiment.

FIG. 2 is a partial schematic perspective view showing a main part of one embodiment.

FIG. 3 is a partial schematic cross-sectional view showing a conventional example.

FIG. 4 is an explanatory diagram illustrating an entire conventional optical deflector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating polygon mirror 2 cover 2a cylindrical wall 3 light source 5 imaging lens system 5a spherical lens 5b toric lens 6 window 7 guide piece 7b eaves 8 flow path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taku Butada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Noboru Nabeda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Hideyuki Miyamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (2)

[Claims] 1. A rotary polygonal mirror for deflecting and scanning illumination light applied to an outer peripheral surface thereof, and a cover having a cylindrical portion covering the outer peripheral surface thereof, and an opening for allowing the illumination light to pass through the cylindrical portion of the cover. Is a light deflector in which the opening faces one surface of an object provided outside the cover, and the cover projects along the other surface of the object. An optical deflector having: 2. The optical deflector according to claim 1, wherein the object and the guide member are separated by 1 mm or more.