JP2000305035A - Scanning optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a dustproofing effect and the suppression of temperature rise by inexpensive constitution. SOLUTION: The lower aperture of a housing 15 is hermetically sealed by using a metal-made printed board 7. The board 7 is formed so as to be exposed outside in the horizontal direction of the housing 15. The housing 15 is fitted to a supporting structure body 13 through the board 7. Besides, a heat conductive resin sheet is arranged between the structure body 13 and the board 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning optical device used for an image forming apparatus such as a laser beam printer.

[0002]

2. Description of the Related Art In general, in a scanning optical device using a laser beam, a polygon scanner in which a polygon mirror is rotated by a polygon motor is mainly used. It is important for the polygon scanner to have a mechanism for preventing dust from entering from outside so as not to stain the internal polygon mirror. In addition, the demand for higher speed and lower noise has been particularly increased, and it has been regarded as an important issue to suppress wind noise and the like when the polygon motor rotates at high speed.
Japanese Patent No. 3615 proposes a structure for sealing a housing. In addition, image quality deterioration and noise reduction due to high-speed rotation vibration are also treated as important issues. Therefore, a conventional example (2) is disclosed in JP-A-7-225348 and a conventional example (3) is disclosed in JP-A-8-201716. Has proposed a structure using a vibration isolating member.

On the other hand, since the polygon scanner rotates at a high speed and deflects the laser beam, reduction of temperature rise due to heat generation is regarded as an important issue. Therefore, a conventional example (4) is disclosed in JP-A-6-230306. Has proposed a method of adhering a heat absorbing member to a light beam scanning control board, and Japanese Patent Application Laid-Open No. Hei 6-300983 has proposed a method of providing a vent and a filter as a conventional example (5).

[0004]

However, if the housing is hermetically sealed to prevent noise as in the conventional example (1), there is a problem that the rise in internal temperature cannot be reduced. For this reason, if a vent is provided as in the conventional example (5) in order to reduce the temperature rise, the polygon mirror is easily affected by dust and clouding occurs, and noise can be suppressed even if a filter is provided. Can not.

Therefore, in order to solve both problems,
As in the conventional example (4), a structure in which the housing is hermetically sealed by a heat absorbing member is conceivable. In this case, it is effective to use an aluminum die-cast housing that can handle a complicated shape with high precision, but is very expensive. is there. Also, as in the conventional example (3), when a polygon scanner often causes noise due to vibrations, the heat radiation design becomes more difficult when a closed state is used in combination with an anti-vibration member. For this reason, an expensive aluminum die-cast housing is used. I can't help but. Therefore, it is desired to reduce the temperature rise by using an inexpensive resin housing.

On the other hand, in recent polygon motors, the structure has changed from a ball bearing to an oil dynamic pressure bearing as a bearing with the increase in speed of rotation. As a result, the rotational vibration frequency is increased, and the image forming apparatus is less than the vibration of the polygon motor itself. Low frequency vibration from the main body is transmitted to the polygon scanner,
It tends to lead to image quality degradation.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the related art, and has as its object to provide a scanning optical device capable of realizing a dustproof effect and suppressing a temperature rise with an inexpensive configuration.

Another object of the present invention is to provide a scanning optical device capable of realizing vibration prevention with an inexpensive configuration.

[0009]

In order to achieve the above object, a first means is a housing for accommodating a scanning optical system, the housing having an opening formed at a lower portion, and a lower opening of the housing. A metal printed circuit board mounted so as to hermetically seal and expose the end to the outside of the housing; and a thermally conductive support structure for mounting the metal printed circuit board to an image forming apparatus. It is characterized by.

[0010] A second means is a board as set forth in the first means, wherein the metal printed board forms an insulating layer on a metal base, forms a conductive pattern thereon, and mounts components thereon. Wherein a back surface on which components are not mounted is attached to the support structure.

The third means is characterized in that a heat conductive resin sheet is interposed between the back surface of the second means on which the components of the metal printed circuit board are not mounted and the support structure.

The fourth means is characterized in that in the third means, the heat conductive resin sheet is interposed over the entire surface of the support structure.

According to a fifth aspect, in the third and fourth aspects, the heat conductive resin sheet has a vibration absorbing function.

According to a sixth aspect, in the first to fifth aspects, a connector is mounted on a region of the metal printed circuit board which is exposed outside the housing.

[0015]

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

FIG. 1 is a configuration diagram showing one embodiment of a scanning optical device according to the present invention. In FIG. 1, a scanning optical device (polygon scanner) 14 has a housing 15 having upper and lower openings, and a cover 16 for covering the upper opening. The housing 15 is mounted on the support structure 13 by screwing or caulking. It is supported by. The support structure 13 is supported between the side plates 11 and 12 on the image forming apparatus side by screwing, caulking, welding, or the like. Support structure 13
Is formed of a metal plate, and if necessary, the side plates 11, 12
Is also formed by a metal plate.

In the housing 15 and the cover 16, a laser emitter (not shown), a collimator lens (not shown) for collimating the laser beam, and the collimated beam are condensed linearly. Synthetic lens (not shown)
And a polygon motor unit 1 for deflecting the linearly condensed light beam in the main scanning direction, and fθ for condensing the deflected light beam to an optimum spot on a photoconductor (not shown). A lens (not shown), a reflecting mirror (not shown) that folds the optical axis of the light beam to secure an optical path length to the photoconductor, and a sealing glass (not shown) for dustproof and soundproofing; And a photosensor (not shown) for obtaining a synchronization detection signal from the deflected light beam.

Since the housing 15 is required to have the above arrangement accuracy, the housing 15 may be formed by a metal mold such as aluminum die-casting which has a high heat radiation effect. However, a fixing device (not shown) on the image forming apparatus side, etc. It may be formed by an inexpensive resin mold in order to block the influence of an external heat source. Cover 16
The material may be resin or metal as long as it can secure vibration resistance and airtightness.

The polygon motor unit 1 includes a polygon mirror 2 and a rotating shaft 3 thereof, a pressing plate 4 for fixing the polygon mirror 2 to the rotating shaft 3, a rotor 5 magnetized with a plurality of poles, and a rotating shaft 3. Oil dynamic pressure bearing 6 for rotating at high speed, metal printed board 7, stator coil 8 mounted on board 7, drive IC 9, connector 10
And so on. The lower opening of the housing 15 is closed by a metal printed circuit board 7, and the metal printed circuit board 7 is formed in such a size that an end thereof is exposed to the outside of the housing 15 in the horizontal direction. The oil dynamic pressure bearing 6 is a metal printed circuit board 7 (and a housing 15).
(A lower opening) and the opening of the support structure 13 so as to be exposed downward. The connector 10 is attached to a region of the metal printed circuit board 7 which is exposed outside the housing 15.

The metal printed board 7 is provided with an insulating layer such as an epoxy layer and an oxide film on a metal base, and a conductive pattern formed thereon. The oil dynamic pressure bearing 6 as a heat source, the stator coil 8 , Has a role as a heat radiating plate for the drive IC 9 and a role as a fixing plate for attaching to the housing 15 with high accuracy. Metal printed circuit board 7
Is attached to the lower portion of the housing 15 by screwing or caulking. At this time, the connector 10 is attached to the outside of the housing 15 on the metal printed circuit board 7, and no parts are mounted on the contact surface 15a between the housing 15 and the metal printed circuit board 7. It is possible to realize both the heat radiation effect and the noise prevention and dust prevention effect without performing the sealing treatment.

The back surface of the metal printed circuit board 7 is formed of a flat surface with no components mounted thereon and has a large surface area.
The heat radiation effect can be enhanced by mounting on top of 3. In order to further enhance the heat radiation effect, heat radiation fins may be provided at appropriate positions on the support structure 13 or cooling air may be applied. Further, the side plates 11 and 12 may be formed of a metal plate to increase the heat radiation area.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, the support structure 13
Between the metal printed circuit board 7 and the heat conductive resin sheet 17
Has been added. Other configurations are the same as those of the first embodiment. The heat conductive resin sheet 17 is a silicon-based sheet evolved from a conventional heat sinker made of silicon grease, and has a structure in which the support structure 13 and the metal surface of the metal printed circuit board 7 are brought into contact with each other as in the first embodiment. Accordingly, it is possible to prevent voids in the heat insulation generated in a microscopic state, and thus it is possible to enhance heat transfer efficiency. Also,
By interposing the heat conductive resin sheet 17, the workability at the time of detachment can be improved.

Next, a third embodiment will be described with reference to FIG. In the above-described second embodiment, the heat conductive resin sheet 17 is configured to have the same size as the metal printed board 7, but the heat conductive resin sheet 18 of the third embodiment is formed of a metal print board. It has a size that covers not only the substrate 7 but also the entire surface of the support structure 13. Other configurations are the same as those of the first and second embodiments. Since the heat conductive resin sheet 18 is a silicon-based sheet softer than metal, it absorbs low frequency vibrations such as micro vibration transmitted from the polygon scanner 14 to the support structure 13 or shock transmitted from the support structure 13 to the polygon scanner 14. Therefore, noise can be suppressed while maintaining the heat radiation effect.

The material of the heat conductive resin sheet 18 is made of heat conductive silicon filled with a glass fiber or a carbon fiber filler. Therefore, it is possible to absorb low-frequency vibrations such as micro-vibrations transmitted to the support structure 13 or shocks transmitted from the support structure 13 to the polygon scanner 14, thereby suppressing noise while maintaining the heat radiation effect.

[0025]

As described above, according to the first aspect of the present invention, the metal printed circuit board is mounted so as to cover the lower opening of the housing and to be exposed to the outside of the housing. Is attached to the image forming apparatus via a thermally conductive support structure, so that a dustproof effect and suppression of temperature rise can be realized with an inexpensive configuration.

According to the invention described in claim 2, the metal printed board is a board in which an insulating layer is formed on a metal base, a conductive pattern is formed thereon, and components are mounted thereon. Since the back surface on which the components are not mounted is attached to the support structure, the dustproof effect and the suppression of the temperature rise can be realized with an inexpensive configuration.

According to the third aspect of the present invention, since the heat conductive resin sheet is interposed between the back surface of the metal printed board on which the components are not mounted and the supporting structure, the dustproof effect and the suppression of the temperature rise can be reduced. It can be realized with a configuration.

According to the fourth aspect of the present invention, since the heat conductive resin sheet is interposed over the entire surface of the support structure,
The dustproof effect and the suppression of temperature rise can be realized with an inexpensive configuration.

According to the fifth aspect of the present invention, since the heat conductive resin sheet has the vibration absorbing function, the dustproof effect, the suppression of the temperature rise and the vibration prevention can be realized with an inexpensive configuration.

According to the sixth aspect of the present invention, since the connector is mounted on the area of the metal printed board exposed outside the housing, the hermeticity of the contact surface between the metal printed board and the housing is maintained. can do.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a scanning optical device according to the present invention.

FIG. 2 is a configuration diagram illustrating a scanning optical device according to a second embodiment.

FIG. 3 is a configuration diagram illustrating a scanning optical device according to a third embodiment.

[Explanation of symbols]

 7 metal printed board 10 connector 11, 12 side plate 13 support structure 15 housing 17, 18 heat conductive resin sheet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kiyoto Kiyoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Koichi Yamazaki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Osamu Yoshioka 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H045 AA33 AA49 AA59 DA02 DA04 DA41 DA44 5C072 AA03 DA04 DA21 HA12 HB15 XA05

Claims (6)

[Claims] 1. A housing for accommodating a scanning optical system, wherein a housing having an opening formed in a lower portion, a housing for closing a lower opening of the housing, and an end exposed to the outside of the housing. A scanning optical device comprising: a metal printed board to be mounted; and a thermally conductive support structure for mounting the metal printed board to an image forming apparatus. 2. The printed circuit board according to claim 1, wherein the metal printed board is a board on which an insulating layer is formed on a metal base, a conductive pattern is formed thereon, and components are mounted thereon, and the back surface on which the components are not mounted. The scanning optical device according to claim 1, wherein the scanning optical device is attached to the support structure. 3. The scanning optical device according to claim 2, wherein a thermally conductive resin sheet is interposed between the back surface of the metal printed board on which the components are not mounted and the support structure. 4. The heat conductive resin sheet is interposed over the entire surface of the support structure.
The scanning optical device according to claim 1. 5. The scanning optical device according to claim 3, wherein the heat conductive resin sheet has a vibration absorbing function. 6. The scanning optical device according to claim 1, wherein a connector is mounted on a region of the metal printed board exposed outside the housing.