JPH055851A - Optical writer - Google Patents

Abstract

PURPOSE:To prevent overheating of a rotating polygonal mirror or a polygonal mirror motor. CONSTITUTION:In an optical writer provided with a polygonal mirror 15 which reflects incident light to scan the light on a photosensitive body and a housing 31 for polygonal mirror which has a transmission glass 32, through which the incident light to and the reflected light from the polygonal mirror 15 are transmitted, and surrounds the polygonal mirror 15, a hole 33 connecting the inside and the outside of the housing 31 for polygonal mirror is provided in a position other than the transmission glass 32 of this housing 31. It is preferable that the housing 31 for polygonal mirror has an upper wall part 34 and the hole 33 is provided in this part 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical writing device installed in an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in an optical writing device provided in a copying machine or the like, a polygon mirror is covered with a housing,
Further, there is a heat radiator plate for cooling the scanner motor provided below the scanner motor, and there is one in which a groove is formed on the surface of the heat radiator plate, that is, the heat radiation surface, as shown in, for example, FIGS.

7 to 9, 1 is a polygon mirror,
2 is a housing, 3 is transparent glass, 4 is an Fθ lens, 5
Is a scanner motor. The polygon mirror 1 reflects the incident light flux and scans the light flux on the photosensitive drum. The housing 2 is formed integrally with the housing of the main body of the optical writing device. The transparent glass 3 seals the polygon mirror 1 together with the housing 2 and at the same time transmits the incident light and the reflected light of the polygon mirror 1. The Fθ lens 4 makes polarization scanning uniform at the time of passing a light beam. The scanner motor 5 rotates the polygon mirror 1 at a constant speed.

On the other hand, 6 is a heat radiating plate and 7 is a groove. The heat radiating plate 6 is attached to the housing 8 of the main body of the optical writing device so as to be located directly below the scanner motor 5, and the groove 7 is the surface of the heat radiating plate. It is formed by cutting out radially. In such an optical writing device, the polygon mirror 1 is sealed by the housing 2 and the transparent glass 3 to prevent wind loss and wind noise due to the rotation of the polygon mirror 1,
Moreover, the area of the heat dissipation surface is increased by the plurality of radial grooves 7 so that the heat dissipation plate 6 can dissipate heat without enlarging it.

[0005]

However, in such a conventional optical writing apparatus, since the polygon mirror 1 is hermetically sealed, the polygon mirror 1 and its peripheral portion are likely to become hot and overheat. was there. As a result, for example, there is a problem that the accuracy of the reflecting surface may change due to thermal expansion of the polygon mirror 1 and the light beam may not be scanned as desired. Also, for example,
When the grease inside the scanner motor 5 evaporates, the grease may adhere to the reflection surface of the polygon mirror 1 and the reflectance of the light beam may decrease.

Further, since the groove 7 is not provided along the wind from the fan (not shown) (indicated by the arrow in the figure),
The wind could not sufficiently pass through the groove 7, and the cooling efficiency was not sufficient. As a result, there is a problem that the heat sink 6 is easily overheated. Therefore, an object of the present invention is to prevent overheating of a rotary polygon mirror or a polygon mirror motor.

[0007]

The invention according to claim 1 is
A rotating polygon mirror that reflects incident light and scans the light on the photoconductor,
An optical writing device comprising: a housing having a light transmitting portion for transmitting incident light and reflected light of the rotary polygonal mirror, the housing being provided so as to surround the rotary polygonal mirror. A through hole that communicates the inside and the outside of the housing is formed,
According to a second aspect of the present invention, in addition to the above configuration, the housing has an upper wall portion, and the through hole is formed in the upper wall portion.

According to a third aspect of the present invention, there is provided a rotary polygon mirror for reflecting incident light to scan the photoconductor with light, a polygon mirror motor for supporting the rotary polygon mirror, and a polygon mirror motor provided in the vicinity of the polygon mirror motor. An optical writing device comprising: a plate member having a heat radiation surface in contact with cooling air, wherein a groove substantially parallel to a flow direction of the cooling air is formed on the heat radiation surface of the plate member. ..

[0009]

According to the first and second aspects of the present invention, since the through hole that communicates the inside and the outside of the housing is formed, the heat easily escapes to the outside when the inside of the housing becomes hot, and the inside of the housing rotates. The area around the polygon mirror is easily cooled. According to the third aspect of the present invention, since a groove that is substantially parallel to the flow direction of the cooling air is formed on the heat dissipation surface of the multi-faceted motor,
Cooling air easily passes through the groove, and the multi-faceted motor is easily cooled.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of an optical writing device according to the invention described in claims 1 and 2. First, the configuration will be described.

1 and 2, reference numeral 11 denotes an optical writing apparatus main body, and the optical writing apparatus main body 11 is provided in, for example, a copying machine,
It has a function as an image forming optical unit that emits a laser beam and scans a photosensitive drum (not shown).
The optical writing device main body 11 includes a main body housing 12, a semiconductor laser unit 13, a cylindrical lens 14, a polygon mirror 15 as a rotary polygon mirror, a scanner motor 16 as a multi-sided boundary motor, an Fθ lens 17, a transparent glass 18, and a mirror 19.
20, a sync detection mirror 21, and a horizontal sync detection device 22.

The semiconductor laser unit 13 collimates the laser beam emitted by the semiconductor laser into a parallel beam and irradiates the cylindrical lens 14 with the collimated beam. The cylindrical lens 14 shapes the parallel light flux to have a predetermined light flux shape and allows the light flux to pass through. Then, the light flux is applied to the polygon mirror 15 supported on the scanner motor 16. The polygon mirror 15 is driven by a scanner motor 16 controlled by a drive board 16a to rotate at a constant speed,
The incident luminous flux is reflected and irradiated on the Fθ lens 17, and finally the photosensitive drum is scanned with the luminous flux. The Fθ lens 17 makes the polarization scanning uniform at the time of passing the light flux. Then, the light flux passes through the transparent glass 18, and the mirrors 19 and 20 are sequentially arranged.
And is imaged on the surface of the photosensitive drum.

The sync detecting mirror 21 reflects a part of the light beam directed to the mirror 19 toward the horizontal sync detecting device 22.
The horizontal synchronization detecting device 22 has an optical fiber 22a and a photoelectric conversion element (not shown), and converts the irradiated light flux into an electric signal and outputs it to a copying machine main body control portion (not shown). On the other hand, as shown in FIG.
A polygon mirror housing 31 is provided around the scanner motor 16 (not shown in FIG. 1). The polygon mirror housing 31 has a transparent glass 32 as a light transmitting portion that transmits incident light and reflected light of the polygon mirror 15, and the polygon mirror 15 and the scanner motor 16 are provided.
Surrounds. In the polygon mirror housing 31, holes 33 are formed at locations other than the transparent glass 32 so that the inside and the outside of the housing 31 communicate with each other. Specifically, the polygon mirror housing 31 has an upper wall portion 34 and a side wall portion 35 which are integrally formed, and a side wall portion 35.
Has a transparent glass 32 attached by cutting out a part of the above, and covers the polygon mirror 15 from above. The hole 33 is formed in the end portion of the upper wall portion 34.

With such a structure, when the temperature inside the housing 31 becomes high, heat easily escapes to the outside, and the polygon mirror 15 inside the housing 31 and its periphery are easily cooled. Therefore, it is possible to prevent the polygon mirror 15 from overheating, and the grease in the motor from scattering due to overheating. Further, the side wall portion 35 can prevent wind loss due to the rotation of the polygon mirror 15. Further, since the hole 33 is not formed so large, it is possible to suppress an increase in wind noise due to the rotation of the polygon mirror 15. it can.

According to the present invention, as shown in FIG. 3, the plate member 36 made of sheet metal or resin is provided with three holes 37 at equal intervals, and then the plate member 36 is attached to the side wall portion 38. You can With such a configuration, the same effect as that of the above-described embodiment can be obtained. The size and shape of the holes in the present invention are not particularly limited as long as the function of the polygon mirror housing 31 is not impaired, and holes other than the holes 33 and 37 may be used. ..

4 and 5 are views showing an embodiment of the optical writing device according to the invention of claim 3. FIG. 4 is a diagram showing a main part of, for example, a copying machine to which this embodiment is applied.
41 is a photoconductor drum, 42 is a charger, 43 is an optical writing device main body (see FIG. 1), 44 is a developing device, 45 is a transfer charger, 46 is a cleaning unit, and 47 is a discharge lamp (details are omitted). ). 48 is a fan,
The fan 48 blows air toward the scanner motor 49 of the optical writing device body 43 in order to remove ozone generated by the charger 42. The scanner motor 49 supports a polygon mirror 50 that reflects incident light and scans the photosensitive drum with light (see FIG. 8).

On the other hand, in FIG. 5, reference numeral 51 denotes a heat radiating plate member. The heat radiating plate member 51 is provided in the vicinity of the scanner motor 49 and radiates heat in contact with the wind (cooling air, arrow in the figure) of the fan 48 described above. It has a face 52. Specifically, the heat dissipation plate member
51 is attached to the housing of the optical writing device main body 43 so as to be located directly below the scanner motor 49 (see FIG. 8). In addition, the heat dissipation surface 52 is formed with a plurality of grooves 53 that are substantially parallel to the wind flow direction.

According to this structure, the wind easily passes through the groove 53 and the scanner motor 49 is easily cooled.
Therefore, overheating of the scanner motor 49 can be prevented. In the present invention, as shown in FIG. 6, the center holes 61a of the plurality of heat radiating plate members 61 are respectively fitted and inserted by the supporting rods 62 so that the heat radiating plate members 61 are substantially parallel to each other in the wind flow direction. A gap 63 may be provided. With such a configuration, not only the wind easily passes through the gap 63, but also the heat radiation surface in contact with the wind increases, so that it is possible to further easily prevent the scanner motor 49 from overheating.

[0019]

According to the first and second aspects of the present invention, the heat easily escapes to the outside when the temperature inside the housing becomes high, so that it is possible to prevent the rotary polygon mirror from overheating. According to the third aspect of the present invention, the cooling air easily passes through the groove, so that the polygon mirror motor can be prevented from overheating.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing an embodiment of an optical writing device according to the first and second aspects of the invention.

FIG. 2 is a view showing a housing and a through hole of the rotary polygon mirror shown in FIG.

FIG. 3 is a diagram showing a housing and a through hole of another embodiment of the optical writing device according to the invention of claim 1;

FIG. 4 is a diagram showing a main part of a copying machine to which an embodiment of the optical writing device according to the invention of claim 3 is applied.

5 is a diagram showing a plate member of the multi-faceted motor of FIG.

FIG. 6 is a view showing a plate member of a multi-faceted motor of another embodiment of the optical writing device according to the invention of claim 3;

FIG. 7 is a diagram showing a housing of a rotary polygon mirror of a conventional example of an optical writing device.

FIG. 8 is a cross-sectional view showing a rotary polygon mirror, a housing and a polygon mirror motor of a conventional example of the optical writing device.

FIG. 9 is a view showing a heat dissipation plate of a polygon mirror motor of a conventional example of the optical writing device.

[Explanation of symbols]

 11 Optical writing device main body (optical writing device) 15 Polygon mirror (rotary polygon mirror) 16 Scanner motor (multi-faceted motor) 31 Polygon mirror housing (housing) 32 Transparent glass (light transmissive part) 33 Hole (through hole) 34 Upper wall part 36 Plate member (upper wall part) 37 Hole (through hole) 43 Optical writing device body (optical writing device) 49 Scanner motor (multi-sided boundary motor) 50 Polygon mirror (rotating polygon mirror) 51 Heat dissipation plate Member (plate member) 52 Heat dissipation surface 53 Groove 61 Heat dissipation plate member (plate member) 63 Gap (groove)

Claims (1)

Claim: What is claimed is: 1. A rotary polygonal mirror for reflecting incident light to scan light on a photosensitive member, and a light transmitting portion for transmitting incident light and reflected light of the rotary polygonal mirror, the rotary polygonal mirror An optical writing device comprising: a housing provided so as to surround a polygonal mirror, wherein a through hole that communicates the inside and the outside of the housing is formed at a location other than the light transmitting portion of the housing. Writing device. 2. The optical writing device according to claim 1, wherein the housing has an upper wall portion, and the through hole is formed in the upper wall portion. 3. A rotary polygon mirror for reflecting incident light to scan light on a photoconductor, and a polygon mirror motor for supporting the rotary polygon mirror.
An optical writing device comprising: a plate member provided near the polygon mirror motor and having a heat radiation surface in contact with cooling air; and a groove substantially parallel to a flow direction of the cooling air is formed on the heat radiation surface of the plate member. An optical writing device characterized by the above.