JPH1152275A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain temperature rise around a rotary polygon mirror housed in a plastic optical box with inexpensive constitution. SOLUTION: The rotary polygon mirror 3 and a driving device 4 for driving the mirror 3 are housed in the plastic optical box 1, and the upper opening part of the optical box 1 is covered with a cover 2 so as to make the optical box 1 in an almost tight closure state. A metallic plate 5 functioning as a member whose heat conductivity is high is grounded on the lower surface of the driving substrate 15 of the device 4, and the trailing end side 5b of the plate 5 is drawn out to the outside while maintaining the almost tight closure state of the optical box 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital copying machine,
The present invention relates to an optical scanning device used for a laser facsimile, a laser printer, a laser plotter, and the like.

[0002]

2. Description of the Related Art In this type of optical scanning device, a rotary polygon mirror (polygon mirror) and a driving device for driving the polygon mirror are housed in an optical box in a substantially hermetically sealed state from the viewpoint of dust prevention and the like. The drive device mainly includes a motor portion and a drive board on which a drive IC for driving the motor portion is mounted. Although heat is generated in the driving IC, the temperature inside the driving IC is likely to rise due to the fact that the space in the optical box is substantially sealed, and if the heat is not sufficiently diffused, the driving IC deteriorates. Or break. To address this issue,
Japanese Patent Application Laid-Open No. Hei 6-230306 discloses a technique in which a heat absorbing member having high thermal conductivity is provided on the back surface of a mounting portion of a driving IC. The heat generated by the driving IC is absorbed by the heat absorbing member, thereby storing heat at the driving IC portion.
Temperature rise is suppressed.

[0003]

In recent years, there has been an increasing demand for higher speed and higher definition in laser printers and the like. In order to increase the speed and the definition, it is necessary to rotate the drive motor of the rotary polygon mirror in the optical scanning device at a high speed. When the rotating polygon mirror is rotated at high speed, the wind noise is increased due to the polygonal shape. The OA equipment is also required to be quiet, and from the viewpoint of suppressing the adhesion of dirt or the like to the rotary polygon mirror, the space in the optical box is substantially in a state using a cover or the like. On the other hand, due to intensified cost competition in recent years, optical boxes in which rotating polygon mirrors are housed are shifting from plastic to metal instead of metal. As a heat source, not only the driving IC part but also the bearing part of the rotary polygon mirror increases frictional heat as the speed of the rotary polygon mirror increases. When the optical box is made of plastic, the thermal conductivity is small, so the heat from these heat generating sources may significantly increase the temperature around the rotating polygonal mirror, thereby deteriorating the optical performance of the rotating polygonal mirror. Was.

The technology described in Japanese Patent Application Laid-Open No. Hei 6-230306 is a technology for radiating heat at a specific portion in a substantially closed optical box, and cannot be applied to the improvement of heat storage in the entire space in the optical box.

Further, depending on the arrangement of the optical scanning device in a machine body such as a digital copying machine, the length of the lead wire for grounding the drive device is often long, and the thickness of the lead wire is reduced due to the influence of noise and the like. If not, the grounding may not be sufficient.

Accordingly, an object of the present invention is to provide an optical scanning device which can solve the problem of temperature rise in the case of a plastic optical box with a simple configuration and also can solve the problem of grounding of a driving device.

[0007]

SUMMARY OF THE INVENTION The present invention is based on the idea of radiating internal heat to the outside while keeping the optical box hermetically sealed. Specifically, according to the first aspect of the present invention, a rotating polygon mirror for deflecting the light beam emitted from the light beam generating means, a driving device for rotating the rotating polygon mirror, and a light beam deflected by the rotating polygon mirror The rotary polygon mirror and the driving device are provided in an optical scanning device housed in a substantially closed plastic optical box, and the optical box maintains the substantially closed state of the optical box. Thus, a member having a high thermal conductivity connecting the internal space of the optical box and the outside is provided.

According to a second aspect of the present invention, in the configuration of the first aspect, the high thermal conductivity member is in contact with the driving device. The aim is to increase the heat dissipation efficiency by directly contacting the heat source.

According to the third aspect of the present invention, the first or second aspect is provided.
In the configuration described above, a configuration is adopted in which the member having high thermal conductivity is a metal plate.

According to a fourth aspect of the present invention, in the configuration of the first aspect, the driving device includes a metal driving substrate, and the member having high thermal conductivity is a metal plate. Is in contact with the ground portion of the electric circuit of the drive board.

According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the metal plate is in contact with a ground portion of the electric circuit of the drive board via a conductive adhesive member. ing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 5 shows a schematic configuration of an optical scanning device to which the present invention is applied. An optical box 1 made of plastic houses a rotating polygon mirror 3 and a driving device 4 for driving the rotating polygon mirror 3 to rotate. The upper opening of the optical box 1 is closed by a cover 2 made of plastic, and its internal space is substantially closed. Laser light as a light beam emitted from a laser oscillator (not shown) serving as light beam generating means attached to the optical box 1 is condensed into a predetermined beam shape by a not-shown cylindrical lens, and then is turned into a polygon mirror 3.
The image is formed on a photosensitive drum 12 through a soundproof glass 9, a lens group 10 as an optical system for forming an image of a laser beam deflected by the rotary polygon mirror 3, and a dustproof glass 11. The embodiments described below are based on such a configuration, and redundant description will be appropriately omitted.

FIG. 1 shows an embodiment corresponding to the first and third aspects. The driving device 4 includes a driving substrate 15 fixed to a support 14 integrally formed on the bottom surface of the optical box 1 and a driving I / O mounted on the upper surface of the driving substrate 15 by means such as soldering.
C16 and a motor portion 17. The motor portion 17 has a known configuration including a rotor, a stator, and the like, and a specific structure is omitted. On the lower surface side of the drive substrate 15, a thin metal plate 5 having a Z-shaped side surface as a member having high thermal conductivity is provided. The front end 5a of the metal plate 5 is fixed to a short column 18 integrally formed on the bottom surface of the optical box 1, and the rear end 5b is drawn out of the optical box 1 and exposed. The right side plate 1b in the drawing of the optical box 1 is provided with a projecting edge 1c which projects horizontally, and the rear end 5b of the metal plate 5 is fixed to a short support 20 integrally formed with the projecting edge 1c. I have.

The right side plate 1 b of the optical box 1 is formed lower than the left side plate 1 a in the drawing, and the dimensional difference is complemented by the thickness of the metal plate 5. That is, the metal plate 5 forms a part of the right side plate 1 b for sealing the inside of the optical box 1, whereby the sealed state inside the optical box 1 is maintained. The width of the metal plate 5 is the width w of the drive substrate 15.
It is set almost the same as (FIG. 5). With this configuration, heat generated in the driving IC 16 and the bearing of the rotary polygon mirror 3 and spread in the optical box 1 travels along the metal plate 5 in the direction of the arrow and is released to the outside.

FIG. 2 shows a second embodiment according to the present invention. The same parts as those in the above embodiment are denoted by the same reference numerals,
Duplicate description is omitted as appropriate. In this embodiment, the metal plate 5 is provided in contact with the back surface of the drive board 15. The heat of the drive IC 16 and the heat of the bearing of the rotary polygon mirror 3 are first radiated through the drive board 15, but since the metal plate 5 is in contact with the drive board 15, The heat radiation efficiency of the device increases.

FIG. 3 shows an embodiment corresponding to claim 4. Note that the same parts as those in the above-described embodiment are denoted by the same reference numerals, and redundant description will be appropriately omitted. In this embodiment, the metal plate 5 is provided in contact with the back surface of the drive substrate 15 as in the above embodiment. A metal portion is exposed on the back surface of the drive substrate 15, and the metal portion is electrically connected to a ground portion of an electric circuit (not shown) of the drive substrate 15. The metal plate 5 is in contact with the exposed metal portion of the drive board 15, so that the metal plate 5 also serves as a part of a conductive wire for grounding the drive board 15. And the rear end 5 of the metal plate 5
b and the grounding portion 7 of the machine body have connection terminals 6 at both ends.
a and 6b are connected by a conductor 6 to form an entire ground line.

FIG. 4 shows an embodiment corresponding to claim 5. Note that the same parts as those in the above-described embodiment are denoted by the same reference numerals, and redundant description will be appropriately omitted. In this embodiment, the metal plate 5 is adhered to the ground portion (metal portion) of the electric circuit exposed on the back surface of the drive board 15 with the conductive double-sided adhesive member 8. When the ground portion of the electric circuit of the drive board 15 and the metal plate 5 have a flat surface with high precision to each other, the best and stable electrical contact is obtained. If the contact is made, the adhesive member 8 is deformed according to the surface properties of both, so that the ground portion of the electric circuit and the metal plate 5
Even if the contact surface is not flat, a good and stable contact state can always be obtained.

[0018]

According to the first aspect of the present invention, the inside and the outside of the plastic optical box are connected by a member having high thermal conductivity while maintaining the optical box in a substantially sealed state. In addition, it is possible to suppress the temperature rise around the rotary polygonal mirror with an inexpensive configuration while ensuring dustproofness of the rotary polygonal mirror and suppressing wind noise caused by high-speed rotation.

According to the second aspect of the invention, in the configuration of the first aspect, a member having a high thermal conductivity is brought into contact with the driving device, so that heat generated from the heat source is directly transferred to the outside. And in addition to the effects of claim 1,
The efficiency of heat radiation to the outside can be further increased.

According to the third aspect of the present invention, in the configuration of the first or second aspect, the member having a high thermal conductivity is a metal plate. Can be achieved.

According to the fourth aspect of the present invention, in the configuration of the first aspect, the member having a high thermal conductivity is a metal plate, and the metal plate is brought into contact with a ground portion of an electric circuit of the drive board. Therefore, the metal plate for heat dissipation can also serve as the grounding lead of the drive board, and therefore, the grounding lead can be easily pulled out from the substantially sealed optical box. In addition, the degree of freedom in turning the grounding conductor can be significantly increased.

According to the fifth aspect of the present invention, in the configuration of the fourth aspect, the metal plate is brought into contact with the ground portion of the electric circuit of the drive board via the conductive adhesive member. In addition to the effect of 4, since the metal plate does not need to be in direct contact with the ground portion of the electric circuit of the drive board, the degree of freedom in the shape and installation method of the metal plate as the heat radiating plate can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of an optical scanning device showing one embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional view of an optical scanning device in an embodiment in which a metal plate is brought into contact with a back surface of a driving substrate.

FIG. 3 is a schematic longitudinal sectional view of an optical scanning device in an example in which a metal plate also serves as a grounding conductor of an electric circuit of a drive board.

FIG. 4 is a schematic longitudinal sectional view of an optical scanning device in an example in which a metal plate is brought into contact with a driving substrate via an adhesive member.

FIG. 5 is a schematic configuration diagram of an optical scanning device to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical box 3 Rotating polygon mirror 4 Drive device 5 Metal plate as a member with high thermal conductivity 8 Adhesive member 15 Drive board

Claims (5)

[Claims] A rotating polygon mirror for deflecting the light beam emitted from the light beam generating means, a driving device for rotating the rotating polygon mirror, and an optic for imaging the light beam deflected by the rotating polygon mirror. A rotary scanning polygon mirror and a driving device, wherein the rotating polygon mirror and the driving device are housed in a substantially sealed plastic optical box. An optical scanning device, comprising: a member having a high thermal conductivity that connects the device to the outside. 2. The optical scanning device according to claim 1, wherein the high thermal conductivity member is in contact with the driving device. 3. The optical scanning device according to claim 1, wherein the member having a high thermal conductivity is a metal plate. 4. The driving device includes a metal driving substrate, and the member having high thermal conductivity is a metal plate, and the metal plate contacts a ground portion of an electric circuit of the driving substrate. The optical scanning device according to claim 1, wherein: 5. The optical scanning device according to claim 4, wherein said metal plate is in contact with a ground portion of an electric circuit of said drive board via a conductive adhesive member.