JP2008181029A - Optical deflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical deflector which radiates heat from a polygon mirror and electronic components etc., by efficiently using an air flow generated with the rotation of the polygon mirror. <P>SOLUTION: A cover is fixed to a base while covering the plurality of electronic components mounted on a substrate, a fixing shaft, a sleeve and the polygon mirror. The cover is provided with a transparent plastic or glass window disposed in the incident/outgoing position of the luminous flux, an air suction hole formed in a region covering the polygon mirror, an air exhaust hole formed in a region covering the plurality of electronic components. A dust catching filter is provided to the air suction hole. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical deflector used in an image forming apparatus such as a laser printer or a digital copying machine.

  Conventionally, as an optical deflector used in an image forming apparatus such as a laser printer or a digital copying machine, one shown in FIG. 11 is known (for example, see Patent Document 1).

The optical deflector includes a columnar fixed shaft 101 fixedly disposed on the housing 100 and a rotating body 110 that is rotatably supported by the fixed shaft 101.
The rotating body 110 includes a rotating shaft 111 disposed with a slight gap between the rotating shaft 111, a ring-shaped magnet 112 fixedly disposed on the upper inner side of the rotating shaft 111, and the rotating shaft 111. A polygon mirror 113 fixedly disposed on the outer side of the central portion and a ring-shaped drive magnet 115 fixedly disposed on the lower outer side of the rotating shaft 111 via a flange 114 are provided.
Reference numeral 116 denotes a groove in which a balance weight (not shown) for correcting the eccentricity of the weight of the rotating body 110 is attached.

  A ring-shaped magnet 102 is fixedly disposed on the outer side of the upper portion of the fixed shaft 101 so as to face a ring-shaped magnet 112 provided on the rotating body 110. The rotating body 110 is supported by the ring-shaped magnets 102 and 112. A thrust magnetic bearing S for bearing in the thrust direction is configured.

  Furthermore, an iron core coil 103 is fixedly disposed in the housing 100 so as to face a ring-shaped driving magnet 115 provided on the rotating body 110, and the rotating body 110 is rotated by the driving magnet 115 and the iron core coil 103. A brushless motor M is configured.

  Of the rotating shaft 111 of the rotating body 110, the inner peripheral surface 111 a facing the fixed shaft 101 is subjected to bearing surface finishing, while the outer periphery of the fixed shaft 101 facing the inner peripheral surface 111 a of the rotating shaft 111. A herringbone-shaped groove 104 is formed on the surface 101a as indicated by a broken line in the drawing, and the rotating body is formed by the grooves 104 provided on the inner peripheral surface 111a of the rotating shaft 111 and the outer peripheral surface 101a of the fixed shaft 101. A radial dynamic pressure bearing R that supports 110 in the radial direction is configured.

In this optical deflector, when the rotating body 110 is rotated by the brushless motor M, the rotating body 110 is supported in a non-contact manner with a fixed distance (gap) with respect to the fixed shaft 101 by the radial dynamic pressure bearing R, and is thrust. The magnetic bearing S supports the fixed shaft 101 at a constant height. Accordingly, there is an advantage that the height of the optical deflector can be made lower than that of a type using a dynamic pressure bearing as a bearing in the thrust direction.
In addition, since the position of the center of gravity of the rotating body 110 can be set to a substantially central position of the rotating body 110, the rotating body 110 can be stably rotated.

  In recent years, the optical deflectors described above have been increased in speed, and noise due to wind noise during rotation has become a problem. Therefore, in order to solve such a problem, a technique of covering the periphery of the polygon mirror 113 with a cover is employed (see, for example, Patent Documents 2 and 3).

JP 05-071532 A JP 11-264949 A Japanese Patent Laid-Open No. 11-183836

  However, since the above-described optical deflector is such that only a part of the optical deflector such as the polygon mirror and the brushless motor is covered with the cover, a part of the brushless motor or the like is generated by the air flow generated by the rotation of the polygon mirror. Only the parts were cooled.

  For this reason, in response to an increase in the amount of heat generated with the recent increase in the rotation speed of the polygon mirror, electronic components on the board other than the polygon mirror in the cover and the brushless motor (for example, a drive element such as a driver IC) ) Has a problem that it is necessary to separately provide a heat radiating means such as a fan and a heat sink.

  Further, since the above-described optical deflector is such that only a part of the optical deflector such as a polygon mirror and a brushless motor is covered by the cover, there is a problem that a space for installing the cover on the substrate is required. there were. That is, since it is necessary to provide a space for mounting no electronic component on the substrate, the substrate itself becomes large, and the entire optical deflector becomes large, resulting in an increase in cost.

Further, since the optical deflector described above uses a window formed in the cover for entering and exiting the light beam as an outlet for air sucked by the rotation of the polygon mirror, it is necessary to open this window. . As a result, there is a problem that dust enters from the opened window when it is stationary and stains the reflection surface of the polygon mirror.
In addition to this, there is a problem that noise accompanying rotation of the polygon mirror leaks from the opened window.

  The present invention has been made to solve such a problem, and not only a polygon mirror and a brushless motor, but also a driving element (electronic component) thereof is covered with a cover so that an air flow generated with the rotation of the polygon mirror is covered. It is an object of the present invention to provide an optical deflector that efficiently uses the heat and radiates heat from the polygon mirror and the electronic component.

  An optical deflector according to claim 1 includes a substrate on which a plurality of electronic components are mounted and provided with a through hole, a base to which the substrate is fixed, and a fixed shaft that is fixed to the base through the through hole of the substrate. In an optical deflector having a sleeve extrapolated to the fixed shaft and a polygon mirror fixed to the sleeve, a plurality of electronic components mounted on the substrate, the fixed shaft, the sleeve and the polygon mirror are covered with the base. A cover is fixed, the cover is made of a transparent plastic or glass window at the part where the light flux enters and exits, the air suction hole at the part covering the polygon mirror, and the air discharge hole at the part covering a plurality of electronic components. The dust suction filter is provided in the air suction hole.

  With this configuration, the air outside the cover is sucked into the cover only from the hole provided in the portion of the cover that covers the polygon mirror by the rotation of the polygon mirror. The sucked air passes through the electronic component mounted on the substrate and is discharged from the hole provided in the part covering the electronic component. Therefore, the polygon mirror is used by using the air flow generated by the rotation of the polygon mirror. In addition to the brushless motor, electronic components can be efficiently cooled.

  In addition, since the window for entering and exiting the light beam is made of transparent plastic or transparent glass, air containing dust does not flow in from the window due to the rotation of the polygon mirror. For this reason, since dust does not accumulate in the cover, the mirror surface of the polygon mirror is not soiled by dust.

  In addition, when the polygon mirror is stopped, dust may enter the cover from the air exhaust hole provided in the part that covers the electronic components. This air exhaust hole allows air to be exhausted when the polygon mirror rotates. Since it becomes an exit, dust that has entered the cover when the polygon mirror is stopped can be discharged when the polygon mirror rotates.

  The optical deflector according to claim 2 is the optical deflector according to claim 1, wherein a plurality of protrusions are provided on the surface of the base, and an air circulation space is provided between the base and the substrate via the protrusions. It is provided.

  According to a third aspect of the present invention, there is provided the optical deflector according to the first aspect, wherein a concave portion is provided in the base, and an air circulation space by the concave portion is provided between the base and the substrate.

  With this configuration, the air flow generated by the rotation of the polygon mirror also flows into the air circulation space between the base and the substrate, so that the generated electronic components are not only from the upper surface of the substrate but also from the lower surface, that is, from both surfaces of the substrate. There is an effect that it can be cooled.

  An optical deflector according to a fourth aspect of the present invention is the optical deflector according to any one of the first to third aspects, wherein the air discharge hole is an electronic component located at an end of the substrate away from the polygon mirror. It is provided in the part which covers.

  With this configuration, since the air flow generated by the rotation of the polygon mirror can be applied to almost all electronic components mounted on the substrate, the cooling efficiency of the electronic components can be improved.

  According to a fifth aspect of the present invention, in the optical deflector according to the fourth aspect, the electronic component located at the end of the substrate away from the polygon mirror is a connector, and from the air discharge hole, The cable is pulled out.

  With this configuration, the substrate can be completely accommodated in the space provided between the base and the case, and an effect is obtained that the wiring from the substrate can be easily pulled out.

  The optical deflector according to claim 6 is the optical deflector according to any one of claims 1 to 5, wherein the cover is mounted on the fixed chamber, the large chamber covering the sleeve and the polygon mirror, and the substrate. A small room that covers a plurality of electronic components, and the corners at the connection between the large room and the small room are R chamfered or C chamfered.

  With such a configuration, when the air flow generated in the large room due to the rotation of the polygon mirror moves (inflows) into the small room, the turbulent flow is caused by the air flow colliding with the corner portion at the connection between the large room and the small room. It is possible to cool the electronic component by reducing the air flow and smoothing the air flow.

  According to the present invention, the air sucked into the cover by the rotation of the polygon mirror passes through the electronic component mounted on the substrate and is discharged from the hole provided in the part covering the electronic component. By using the generated air flow, not only the polygon mirror and the brushless motor but also the electronic components can be efficiently cooled.

  Hereinafter, the present invention will be described in detail using examples.

A first embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a side sectional view of an optical deflector. FIG. 2 is a perspective view of the optical deflector shown in FIG.

  The optical deflector 1 has an aluminum base 2 and a plurality of electronic components 12 to 14 mounted thereon, a substrate 15 fixed to the base 2, and screws or the like so as to pass through the through holes 16 of the substrate 15. Covering the fixed columnar and metal fixed shaft 3, the rotating body 4 rotatably supported by the fixed shaft 3, the plurality of electronic components 12 to 14, the fixed shaft 3, and the rotating body 4, The cover 19 is fixed to the base 2.

  The rotating body 4 has a cylindrical shape that is extrapolated with a slight gap between the rotating shaft 4 and a metal sleeve 5, an aluminum flange 6 fixed to the sleeve 5, and the flange. An aluminum polygon mirror 7 which is placed on the outer peripheral surface and has a plurality of mirror surfaces formed thereon, an elastic member 8 such as a ring-shaped leaf spring placed on the polygon mirror 7, and the elastic member. The pressing member 9 made of aluminum, which is placed on the upper surface 8 and is forcibly inserted into the upper portion of the sleeve 5 by pressing or shrink fitting so as to press the polygon mirror 7 against the flange 6, and the inner peripheral surface of the flange 6. The driving magnet 10 is fixed with an adhesive or the like, and the lid 25 is fixed to the upper end of the sleeve 5.

  The base 2 is mounted with a substrate 15 on which electronic components 12 to 14 are mounted and a through hole 16 is formed. A coil 17 is fixed to the substrate 15 at a position facing the drive magnet 10, and a brushless motor 18 is formed by the drive magnet 10 and the coil 17.

  The polygon mirror 7 and the brushless motor 18 described above are entirely covered with a cover 19 in order to prevent noise generated by rotation and to prevent dust.

  The cover 19 is provided with a hole 20 at a portion where a light beam enters and exits, and a transparent part made of plastic or glass is fitted into the hole to form a window 21.

  The cover 19 is provided with an air suction hole 22 in the upper part of the polygon mirror 7 that covers the polygon mirror 7, and an air discharge hole 23 in the part that covers the electronic components 12 to 14. A dust supplement filter 24 is provided in the air suction hole 22 to remove dust contained in the air sucked into the cover 19 by the rotation of the polygon mirror 7.

Hereinafter, the operation of the optical deflector 1 having the above configuration will be described.
When the polygon mirror 7 is rotated by the brushless motor 18, air outside the cover 19 flows into the cover 19 from the dust capturing filter 24 provided in the air suction hole 22. Then, the air flow flows from the upper side to the lower side of the polygon mirror 7, and hits or passes through a plurality of electronic components mounted on the substrate 15 in the order of the electronic component 12, the electronic component 13, and the electronic component 14. It flows through the cover 19 and is discharged from the air discharge hole 23.

  For this reason, since the air flow generated by the rotation of the polygon mirror 7 always hits or passes through the electronic components 12 to 14, the electronic components 12 to 14 are efficiently cooled without providing a heat radiating member such as a heat sink. Is done.

  Moreover, since the air discharge hole 23 is provided in the upper part of the electronic component 14 which is a site | part which covers the electronic component 14 located in the edge part 11 of the board | substrate 15 away from the polygon mirror 7, when the polygon mirror 7 stops, It is conceivable that dust enters the cover 19 from the air discharge hole 23 and accumulates on the electronic component 14. However, since the air in the cover 15 is discharged from the air discharge hole 23 by the rotation of the polygon mirror 7, it is not necessary to provide a dust supplement filter in the air discharge hole 23.

  The parts such as the polygon mirror 7 also generate heat due to the rotation of the rotating body 4. Needless to say, these parts are also cooled by the air flow generated by the rotation of the polygon mirror 7.

Another embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 3 is a side sectional view of the optical deflector. FIG. 4 is a perspective view showing a base and a substrate of the optical deflector of FIG.
Note that the same portions as those of the optical deflector according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The optical deflector 1 according to the second embodiment is different from the first embodiment only in that a plurality of protrusions 26 are provided on the surface of the base 2 and an air circulation space is provided between the base 2 and the substrate 15. It is.

  With this configuration, a part of the air flow generated in the cover 19 due to the rotation of the polygon mirror 7 enters the air circulation space 36 from the gap 27 between the base 2 and the substrate 15 and is discharged from the gap 28 between the base 2 and the substrate 15. The For this reason, since the board | substrate 15 is cooled from both the front surface and both back surfaces by an air flow, there exists an effect that the heat | fever of the electronic components 12-14 can be cooled efficiently.

  The protrusions 26 may be integrally formed by cutting the base 2 or the like, and after cutting the surface of the base 2, another member such as a spacer is bonded and fixed to the base 2. You may do it.

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 5 is a side sectional view of the optical deflector.
Note that the same portions as those of the optical deflector according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The difference between the optical deflector 1 according to the third embodiment and the first embodiment is that the electronic component located at the end 11 of the substrate 15 away from the polygon mirror 7 is a connector 29, and from the air discharge hole 23, The only point is that the cable 30 of the board 15 is pulled out.

  With such a configuration, the substrate 15 can be completely accommodated in the space provided between the base 2 and the case 19, and the wiring from the substrate 15 can be easily pulled out of the cover 19.

  That is, an optical deflector can be manufactured at low cost by using the air discharge hole 23 as a discharge port for an air flow generated by the rotation of the polygon mirror 7 and as a discharge port for wiring such as a signal line of the substrate 15. Can do.

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 6 is a side sectional view of the optical deflector.
Note that the same portions as those of the optical deflector according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The difference between the optical deflector 1 according to the fourth embodiment and the first embodiment is that the inside of the cover 15 is mounted on the substrate 15 and the large chamber 30 that covers the fixed shaft 3, the sleeve 5, the polygon mirror 7, and the like. The small part 31 that covers the electronic part 13 and the electronic part 14 is provided, and the corner part 32 of the connecting part 33 between the large room 30 and the small room 31 is only chamfered.

  With this configuration, when the air flow generated in the large room 30 due to the rotation of the polygon mirror 7 moves (inflows) to the small room 31, the air flows into the corner portion 32 of the connecting portion 33 between the large room 31 and the small room 30. The turbulent flow generated by the collision is reduced, and there is an effect that the electronic components 12 to 14 can be efficiently cooled by smoothing the air flow.

  The R chamfer at the corner 32 shown in FIG. 6 may be a C chamfer as shown in FIG.

Another embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 7 is a side sectional view of the optical deflector. FIG. 8 is a perspective view of the optical deflector shown in FIG.
Note that the same portions as those of the optical deflector according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The optical deflector 1 according to the fifth embodiment is different from the first embodiment in that the air discharge hole 34 covers the electronic component 14 at the position of the substrate 15 away from the polygon mirror 7, It is only a point opened on the side.

  With this configuration, the air discharge hole 34 is not facing upward like the air discharge hole 23 described above, and therefore, there is an effect that it is difficult for dust to enter the cover 19 when the polygon mirror 7 is stopped. Further, dust that has entered the cover 19 from the air discharge hole 34 when the polygon mirror 7 is stopped can be discharged from the air discharge hole 34 by the air flow generated by the polygon mirror 7.

  In the optical deflector described in the fifth embodiment, the air flowing into the small room 31 from the large room 30 due to the rotation of the polygon mirror 7 does not change the course, and then straightly enters the air discharge hole 34. Since it progresses and is discharged | emitted as it is, the thermal radiation efficiency of electronic components 12-14 grade | etc., Can be improved rather than the optical deflector 1 of Example 1. FIG.

  The above-described embodiments are merely illustrative and are not intended to limit the present invention. The present invention can be recognized by the parties from the claims, the detailed description of the invention, and the drawings. Modifications and additions can be made without departing from the technical idea of the invention.

  For example, in the above-described embodiment, the polygon mirror 3 is fixed to the flange 5. However, the polygon mirror 3 may be directly fixed to the rotary shaft 10 by press fitting or the like.

  As shown in FIG. 9, the convex portion 26 provided on the surface of the base 2 in the second embodiment may be a concave portion 35 provided by cutting the surface of the base 2. Even in such a configuration, since the air circulation space 36 can be formed between the substrate 15 and the base 2, the air flow generated by the rotation of the polygon mirror flows into the air circulation space between the base and the substrate, The heated electronic component can be cooled also from the lower surface of the substrate.

  Furthermore, in the above-described embodiment, although aluminum is used as the material of the base 2, a metal other than aluminum, for example, a zinc alloy may be used. The reason is that the zinc alloy has a high specific gravity with respect to aluminum and has vibration damping properties, and the zinc alloy has substantially the same thermal conductivity as aluminum and has good heat dissipation.

  The present invention is applied to an optical deflector used in an image forming apparatus or the like.

(Example 1) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 1) which is a perspective view of the optical deflector which concerns on this invention. (Example 2) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 2) which is a perspective view of the base and board | substrate of an optical deflector which concern on this invention. (Example 3) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 4) which is a perspective view of the optical deflector which concerns on this invention. (Example 5) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 5) which is a perspective view of the optical deflector which concerns on this invention. It is a perspective view of the base of the optical deflector concerning the present invention. It is side part sectional drawing of the optical deflector which concerns on this invention. It is side part sectional drawing explaining the conventional optical deflector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical deflector 2 Base 3 Fixed axis | shaft 5 Sleeve 7 Polygon mirror 12 Electronic component 13 Electronic component 14 Electronic component 15 Board | substrate 18 Brushless motor 19 Cover 21 Window 22 Air suction hole 23 Air discharge hole 24 Dust supplement filter 26 Protrusion

Claims (6)

A substrate on which a plurality of electronic components are mounted and through holes are provided;
A base to which the substrate is fixed;
A fixed shaft fixed to the base through the through hole of the substrate;
A sleeve extrapolated to the fixed shaft;
In an optical deflector having a polygon mirror fixed to the sleeve,
Covering the plurality of electronic components mounted on the substrate, the fixed shaft, the sleeve and the polygon mirror, and fixing a cover to the base;
The cover is provided with a transparent plastic or glass window at a part for entering and exiting a light beam, an air suction hole at a part covering the polygon mirror, and an air exhaust hole at a part covering the plurality of electronic components,
An optical deflector provided with a dust supplement filter in the air suction hole Providing a plurality of protrusions on the surface of the base,
The optical deflector according to claim 1, wherein an air circulation space is provided between the base and the substrate via the protrusion. Providing a recess in the base;
The optical deflector according to claim 1, wherein an air circulation space by the concave portion is provided between the base and the substrate.   The optical deflector according to any one of claims 1 to 3, wherein the air discharge hole is provided in a portion covering the electronic component located at an end portion of the substrate away from the polygon mirror. The electronic component located at the end of the substrate away from the polygon mirror is a connector;
The optical deflector according to claim 4, wherein a cable of the substrate is pulled out from the air discharge hole. The cover has a large chamber that covers the fixed shaft, the sleeve, and the polygon mirror, and a small chamber that covers the plurality of electronic components mounted on the substrate,
The optical deflector according to any one of claims 1 to 5, wherein a corner portion at a connection portion between the large room and the small room is R-chamfered or C-chamfered.

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