JP2001242408A - Polygon motor unit, optical scanner, and image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the heat deformation of an image-formation optical system, a mirror, etc., for the optical scanning caused by generation of heat of a polygon motor shaft receiving part, which rotationally drives a polygon mirror for an optical scanners used for an image forming device. SOLUTION: A radiating means (heat conducting material 69 and a fin 69a) to radiate the heat generated in a heat generating part (a bearing 63) of the polygon motor is set in a polygon motor unit 60, and the excessive generation of heat is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polygon motor unit, an optical scanning device, and an image forming apparatus.

[0002]

2. Description of the Related Art There is known an image forming apparatus in which a charged image carrier is exposed to light from an optical scanning device to form an electrostatic latent image and to provide an image. FIG. 6 shows an example of a multicolor image forming apparatus as an example of the image forming apparatus.

In FIG. 6, an image forming section as a plurality of electronic processing sections is arranged along a sheet conveying path, and each time a sheet as a recording medium passes through each image forming section, an image of a different color is formed. Are sequentially transferred onto a recording medium, and a color image is finally obtained by superimposing the four colors.

[0004] Each image forming section includes a photosensitive member 1 for black.
K, photoconductor 1M for magenta, photoconductor 1 for yellow
A photoconductor 1C for Y and cyan, a charging device 2K disposed around these photoconductors, a charging device 2M for magenta,
A charging device 2Y for yellow, a charging device 2C for cyan,
Developing device 3K for black, developing device 3 for magenta
M, yellow developing device 3Y, cyan developing device 3
C, a cleaning device 4K for black, a cleaning device 4M for magenta, a cleaning device 4Y for yellow, a cleaning device 4C for cyan, and the like.

The optical scanning device 5 includes a polygon motor unit 6, an imaging optical system 7 for guiding light from the polygon motor unit 6 to form an image on the photosensitive members 1K, 1M, 1Y, and 1C as scanning surfaces. It comprises a mirror 8, a polygon motor unit 6, an imaging optical system 7, and a housing 15 for holding the mirror 8. The imaging optical system 7 includes an fθ lens 7a and an imaging lens 7b. The polygon motor unit 6 includes a polygon mirror 9 for deflecting laser light by rotation, and a polygon motor 10 for driving the polygon mirror 9 to rotate.

The optical scanning device 5 bends the laser beam emitted from the polygon motor unit 6 through the fθ lens 7a, the mirror 8, the imaging lens 7b, etc., and charges the laser beam in advance by the charging devices 2K, 2M, 2Y, and 2C. Each of the photoconductors 1K, 1M, 1Y, and 1C is exposed, and the surface of each photoconductor is exposed and scanned in a main scanning direction perpendicular to the paper surface to form an electrostatic latent image corresponding to each color.

These electrostatic latent images are developed by developing devices 3K, 3M,
Each of the transfer chargers 50C, 50Y, and 50 is visualized by 3Y and 3C, is fed from the paper supply unit 14, and is conveyed by the conveyor belt 11 in the sub-scanning direction onto the recording medium 12.
M and 50K are sequentially transferred in a superimposed manner at a transfer section, and a color image is finally obtained by superimposing four colors, and is discharged onto a discharge tray 40 (not shown) via the fixing device 13.

In such an image forming apparatus, usually,
The polygon mirror 9 rotates at several thousand to tens of thousands of revolutions per minute. For this reason, heat is generated from the polygon motor unit 6, and the heat is transmitted through the housing 15 of the optical scanning device 5, and fθ
The image forming optical system such as the lens 7a and the image forming lens 7b, the mirror 8 and its receiving portion are deformed, and the laser light
Disturbance occurs in the image formation on K, 1M, 1Y, and 1C.
In recent years, this problem has become more severe with respect to changes in temperature, since lenses have tended to be plastic molded for cost reduction.

As a countermeasure, Japanese Patent Application Laid-Open No. Hei 5-34623 discloses that the ceiling of the container of the imaging optical system is made to have a ventilation property so as to ventilate with outside air. Since the portion having air permeability also functions as a filter, a large flow rate of outside air cannot be expected.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to pay attention to the fact that heat generated in a polygon motor unit is mainly generated in a polygon motor unit, and to effectively radiate the heat generated in the polygon motor unit. An object of the present invention is to provide a polygon motor unit, an optical scanning device, and an image forming apparatus that solve the problem caused by heat.

[0011]

The present invention has the following configuration to achieve the above object. (1). In a polygon motor unit including a polygon mirror that deflects laser light by rotation and a polygon motor that rotationally drives the polygon mirror, heat radiating means for radiating heat of the polygon motor is provided in the polygon motor. Claim 1). (2). (1) In the polygon motor unit described in (1), the heat radiating means is made of a heat conductive member, and one end side of the heat conductive member is fixedly contacted with the polygon motor side,
Radiation fins are formed on the other end of the heat conducting member (claim 2). (3). (1) In the polygon motor unit described in (1), the heat radiating means comprises a heat exchange member, and one end of the heat exchange member is fixedly contacted with the polygon motor side.
The other end is extended to the heat radiation environment area (claim 3). (4). (1) In the polygon motor unit described in (1), the heat dissipating means comprises a heat conducting member and a heat exchanging member provided on the heat conducting member, and one end of the heat conducting member is fixedly contacted to the polygon motor side. A radiation fin is formed on the other end of the conduction member, one end of the heat exchange member is fixedly contacted with the other end of the heat conduction member, and the other end is extended to a radiation environment area. (Claim 4). (5). A polygon motor unit, an imaging optical system and a mirror for guiding light from the polygon motor unit to form an image on a surface to be scanned, and a housing for holding the polygon motor unit, the imaging optical system and the mirror. In the optical scanning device, the polygon motor unit described in any one of (1) to (4) is attached to a groove-shaped flow path for introducing outside air formed on an outer surface of the housing, and the heat radiating means is positioned in the flow path. (Claim 5). (6). An image forming apparatus configured to form an electrostatic latent image by exposing the charged image carrier with light from an optical scanning apparatus and to provide an image forming apparatus, the apparatus including the optical scanning apparatus according to (5). (Claim 6).

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Members having the same functions as those of the members already described in the following embodiments will be denoted by the same reference numerals as much as possible, and description thereof will be omitted unless particularly necessary. Example 1 This example corresponds to claims 1 and 2. This will be described with reference to FIG. In FIG. 1, a polygon motor unit 60 according to the present invention is covered by a casing with an upper case 61 and a flange 62 as a lower case.

A cylindrical body is formed on the inner lower surface of the flange 62, and the outer periphery of the cylindrical body is fixed with a stator coil 66 surrounding it. The stator coil 66 is provided on a circuit board 65 fixed to the flange 62. A polygon mirror shaft 64 is fitted inside the cylindrical body via a bearing 63. The polygon mirror 30 is provided above the polygon mirror shaft 64, and the rotor 72 is provided integrally with the polygon mirror shaft 64 at the intermediate portion.

The polygon mirror shaft 64 is rotated at a high speed by the status coil 9 and the circuit board 65, and the laser beam Lb taken in from a light entrance opening (not shown) is emitted from the exit port 6.
It is emitted from 7, 68. During this rotation, the bearing 6
Heat is generated at a sliding portion between the shaft 3 and the polygon mirror shaft 64.

In the present embodiment, a cylindrical base 63a having a circular flat surface is formed on the outer surface of the flange 62 and opposite to the shaft end of the polygon mirror shaft 64, and the same shape of heat is formed on this flat surface. The flat end face on one end side of the conductive material 69 was brought into close contact and fixed to the flange 62 with a screw (not shown). The heat conductive material 69 is made of a material having good heat conductivity, in this example, aluminum. The fin 6 is provided at the other end of the heat conductive material 69.
9a is formed to enhance the performance.

The polygon motor unit 60 is attached by forming a mounting seat at a corresponding portion of the housing 15 so that the flange 62 projects out of the housing 15 of the optical scanning device 1. Screws 71 to the housing 15 through
It is fixed by.

In this example, the heat conducting material 69 is a heat radiating means. The heat generated at the bearing 63 is transmitted from the circular base 63a of the flange 62 to the heat conducting material 69 and is efficiently radiated from the fins 69a. Here, the heat conductive material 69 is a fin 69a serving as a heat radiating portion at an arbitrary portion, in this example, the housing 1
It plays the role of leading outside of 5. Since the fins 69 a provided at the ends of the heat conductive material 69 are exposed outside the housing 15, heat is radiated outside the housing 15 without increasing the temperature inside the housing where heat is easily stored. .

The position where the fins 69A are placed is usually outside the housing 15 as in this embodiment, but as another example, the position of the image forming apparatus that covers the housing 15 and other image forming members is described. If the layout is close to the frame, it may be outside the frame.

In this embodiment, one end of the heat conductive material 69 is brought into contact with the heat-generating portion of the polygon motor unit 60 so that the bearing 6
The heat generated by the heat conducting member 3 is removed, and the heat is dissipated in a heat dissipating environment at a heat dissipating fin 69a provided on the other end of the heat conductive material 69. If the size of the heat conductive material 69 is increased, the fins 69
The position a can be extended to an arbitrary position.

Since the heat insulating material 70 is interposed in the mounting portion of the polygon motor unit to the housing 15, the heat of the polygon motor unit 60 is not transmitted to the housing 15, so that the temperature of the optical scanning device 5 rises. Can be prevented.

Accordingly, thermal deformation of the image forming optical system and mirrors in the optical scanning device 5 is eliminated, and the photosensitive members 1K, 1M, 1
Stable imaging can be performed on Y and 1C.
Further, since it is not necessary to introduce outside air and radiate heat to the imaging optical systems such as the fθ lens 7a, the imaging lens 7b, and the mirror 8 provided in the housing 15, these imaging optical systems are included in the outside air. Does not get dirty with dust. In addition, there is no need for a filter for removing dust, and serviceability is improved. Example 2. This example corresponds to claims 1 and 3. In the following embodiments, members having the same functions as those of the members already described are denoted by the same reference numerals as much as possible, and description thereof will be omitted unless it is particularly necessary.

Although not shown in FIG. 2, in this embodiment, the polygon motor unit 60 is fixed to the outside of the housing 1 via a heat insulating material 70 as in FIG. I do.

In this embodiment, the heat conductive material 69 shown in FIG.
, A heat conductive material 690 is provided. This heat conductive material 6
The fins 90 are not provided unlike the heat conductive material 69 in the above example. The heat conductive material 690 is made of an aluminum material having good heat conductivity, and is fixed to the flange 62 such that one end thereof is in close contact with the flat surface of the circular base 63a.

The other end of the heat conductive material 690 is a flat surface, and one end of the heat exchange member 74 is fixed to this flat surface in close contact. The other end of the heat exchange member 74 extends to a heat radiation environment region having a temperature difference lower than the temperature of the bearing 63 and having a temperature difference. As this heat radiation environment area,
It may be inside the frame 20 in the example of the color image forming apparatus shown in FIG.

From the other end of the heat exchange member 74, the frame 20
The temperature inside the frame 20 rises due to the heat dissipated therein, which can be achieved by the ventilation fan 21 that radiates the heat inside the frame 20 to the outside. In addition, the heat exchange member 74 can be extended to the outside of the frame 20,
In that case, the outside of the frame 20 is a heat radiation environment area. This can be considered when the ventilation fan 21 is not provided, or when sufficient heat exchange cannot be obtained in the frame 20 even when the ventilation fan 21 is provided.

The heat exchange member 74 has a large number of tubes formed in a sheet-like case having good heat conductivity, and the inside of these tubes is filled with a fluid for heat exchange having extremely good heat conductivity. This is known as a known heat exchange member.
When there is a temperature difference between the one end side and the other end side of the heat exchange member 74, the heat exchange fluid absorbs (or releases) heat at one end side and releases heat at the other end side. Heat exchange.

As in this example, one end 7 of the heat exchange member 74
The heat of the bearing 63 is radiated through the heat exchange member 74 by adhering the heat conductive material 4a to the heat conductive material 74 and exposing the other end 74b to a low-temperature heat radiation environment having a temperature difference with respect to the bearing 63. Is done. In this example, the heat exchange member 74 is provided via the heat conductive material 690. However, the heat exchange member 74 may be directly adhered and fixed to the circular base 63a without the heat conductive material 690.

In this embodiment, the heat exchanging action of the heat exchanging member 74 and the other end of the heat exchanging member can be extended to an arbitrary heat radiating environment. There are advantages. Example 3 This example corresponds to claims 1 and 4. In the following embodiments, members having the same functions as those of the members already described are denoted by the same reference numerals as much as possible, and description thereof will be omitted unless it is particularly necessary.

Although not shown in FIG. 3, the polygon motor unit 60 is fixed to the outside of the housing 1 via a heat insulating material 70 in this embodiment, similarly to FIG. I do.

In this embodiment, the heat conductive material 69 shown in FIG.
Instead of heat conducting material 690 having fins 6900a
0, and a heat exchange member 74 similar to that shown in FIG. Since the heat conductive member 6900 has the heat exchange member 74 attached thereto, the portion where the fins 6900 a are formed is a portion corresponding to the back side of the mounting surface of the heat exchange member 74, and is provided inside the heat conductive member 6900. Thermal conductive material 690
Numeral 0 is made of an aluminum material having good heat conductivity, and is fixed to the flange 62 such that one end thereof is in close contact with the flat surface of the circular base 63a.

In this embodiment, heat radiation by the fins 6900a and
Due to the two heat radiation effects of heat exchange by the heat exchange member 74,
The heat of the polygon motor unit is dispersed and radiated. For this reason, there is an advantage that the heat radiation action is further promoted and the degree of freedom in selecting the heat radiation part in the heat exchange member 74 is obtained. Example 4. This example corresponds to claim 5. In the following embodiments, members having the same functions as those of the members already described are denoted by the same reference numerals as much as possible, and description thereof will be omitted unless it is particularly necessary.

As shown in FIG. 4, in this embodiment, the polygon motor unit 60 described with reference to FIGS.
In a state in which the heat conductive members 69, 690, and 6900 are turned upside down so that the heat conductive members 69, 690, and 6900 protrude outward from the upper surface of the housing 15, a method similar to the mounting mode via the heat insulating material 70 shown in FIG. , Attached to the housing 15. For further details, see FIG.
As shown in FIG. 7, a rectangular groove 15a for introducing outside air is formed in the housing 15, and the housing 15 is fixed at a portion of the housing 15 corresponding to the bottom of the groove 15a.

The polygon motor unit 60 is located substantially at the center of the housing 1 in the depth direction.
The 0 side is located inside the housing 1, and the portion on the motor side opposite to the polygon mirror 30, that is, the side where the heat radiating means on the bearing 63 side is provided, is the housing on which the imaging optical system, the mirror, and the like are arranged. The inside of the body 15 is isolated at the bottom of the housing 15.

The open side of the groove 15a is covered with a cover 80 so as to form a duct having a rectangular cross section. By flowing outside air from one direction of the duct by a fan motor (not shown) or the like, the fins 69 in the polygon motor units 69 and 6900 in the example of FIG.
a, 6900a can be cooled.

As a fan motor for flowing outside air into the duct, a dedicated fan motor can be used, or a fan motor 21 in the image forming apparatus 100 can be used as shown in FIG. Fan motor 2
When 1 is used, a guide is provided as appropriate so that the flow of the air flow passes through the groove 15a.

In the polygon motor unit 690 in the example of FIG. 2, there is a degree of freedom in the heat radiation environment area where the other end side 74b of the heat exchange member 74 is located, and since this heat radiation environment area can be selected outside the duct, the groove is formed. When the other end side 74b of the heat exchange member 74 extends to the outside of 15a, it is not necessary to provide a cover 80 to form a duct, but the other end side 74b of the heat exchange member 74 is located in the groove 15a. In this case, since heat is radiated from the portion, a cover 80 is provided in the groove 15a to form a duct, and outside air flows through the duct, as in the examples of FIGS. Thereby, heat exchange is effectively performed by the fins 69a and 6900a and the heat exchange member 74. Example 5 This corresponds to claim 6. The present embodiment relates to an image forming apparatus using the optical scanning device having the configuration shown in FIG. 4 or the optical scanning device having the polygon motor unit shown in FIGS.

An example of a color image forming apparatus will be described with reference to FIG. 5, the basic configuration of the color image forming apparatus 100 is the same as that shown in FIG. The main difference is that the heat conductive material 6 of the polygon motor unit 60
9 (690, 6900) outside the housing 15, and the frame 2 covering the entire color image forming apparatus.
That is, a ventilating fan 21 for releasing the heat inside 0 to outside of the frame is provided.

The heat of the bearing portion of the polygon motor unit 60 is radiated outside the housing 15 and into the frame 15 via the heat conductive material 69 (690, 6900). The heat inside the frame 15 is released outside the frame by the ventilation fan 21.

In this color image forming apparatus, a color separation image signal obtained by reading a document (not shown) on the contact glass 23 by the color image reading device 22 in advance when forming a color image is converted into a color image. Color conversion processing is performed by the image processing unit 24 based on the intensity level,
The image data is converted into black, magenta, yellow, and cyan color image data, and a laser light source is controlled to emit light in accordance with the color image data, and the photoconductors 1K, 1
A color image is written to M, 1Y, and 1C. The contact glass 23 can be covered by a pressure plate (not shown).

In the color image forming apparatus of this embodiment, since the heat from the polygon motor unit 60 is radiated, fθ
The deformation of the image forming optical system such as the lens 7a and the image forming lens 7b, the mirror 8 and its receiving portion due to heat is eliminated, and the disturbance of the image formation of the laser light on the photoconductors 1K, 1M, 1Y and 1C is eliminated. . In recent years, due to cost reduction, the lens tends to be made of plastic mold and is likely to be thermally deformed. However, by providing heat dissipation means to the polygon motor as in this example, a resin imaging optical system is formed. The thermal deformation that affects the image quality can be eliminated.

Although the full-color image forming apparatus has been described above, the present invention is not limited to this, and the polygon motor unit and the optical scanning apparatus of the present invention can be applied to a single-color image forming apparatus as in the color image forming apparatus. Can be used. Further, the present invention can be applied to a polygon motor unit, a facsimile using an optical scanning device, various kinds of printers, copying machines, and the like, and the same technical advantages as those described in the above examples can be obtained.

[0042]

According to the first aspect of the present invention, since the heat generation of the polygon motor unit is suppressed, the optical scanning device or the image forming apparatus using the polygon motor unit may suffer from the disturbance of the written image due to the temperature rise. Eliminate inconvenience.

According to the second aspect of the present invention, the heat generated by the polygon motor unit is efficiently radiated by the radiation fins via the heat conducting member.

According to the third aspect of the present invention, the heat exchange member 74
Of the polygon motor unit can be extended to a part of an arbitrary heat radiation environment, so that the degree of freedom in selecting the heat radiation part can be obtained, and the heat exchange member can effectively suppress the temperature rise of the polygon motor unit.

According to the fourth aspect of the present invention, the heat radiation of the polygon motor unit is further promoted by the heat radiation effect of the cooperation of the heat conductive material and the heat exchange member, and the degree of freedom in selecting the heat radiation portion in the heat exchange member is obtained. Can be

According to the fifth aspect of the present invention, a further heat radiation effect can be obtained by introducing outside air into the groove-shaped flow path.

According to the sixth aspect of the present invention, by eliminating thermal deformation of the imaging optical system and the mirror, it is possible to eliminate the disturbance of the image written on the image carrier and prevent the image quality from deteriorating.

[Brief description of the drawings]

FIG. 1 is a sectional view of a polygon motor unit according to the present invention.

FIG. 2 is a sectional view of a polygon motor unit according to the present invention.

FIG. 3 is a sectional view of a polygon motor unit according to the present invention.

FIG. 4 is a perspective view showing a state where the polygon motor unit according to the present invention is attached to a housing.

FIG. 5 is a schematic configuration diagram of a color image forming apparatus according to the present invention.

FIG. 6 is a schematic configuration diagram of a conventional color image forming apparatus.

[Explanation of symbols]

 5 Optical Scanning Device 60 Polygon Motor Unit 69, 690, 6900 Thermal Conductive Material 69a, 6900a Fin 100 Color Image Forming Apparatus

Claims (6)

[Claims] 1. A polygon motor unit comprising: a polygon mirror for deflecting laser light by rotation; and a polygon motor for rotating and driving the polygon mirror. A polygon motor unit that is installed on a motor. 2. The polygon motor unit according to claim 1, wherein said heat radiating means comprises a heat conductive member, one end of said heat conductive member is fixedly contacted to said polygon motor side, and the other end of said heat conductive member is connected to said polygon motor. Is a polygon motor unit characterized by forming heat radiation fins. 3. The polygon motor unit according to claim 1, wherein said heat radiating means comprises a heat exchanging member, one end of said heat exchanging member being fixedly contacted with said polygon motor, and the other end extending to a heat radiation environment area. A polygon motor unit characterized by being issued. 4. The polygon motor unit according to claim 1, wherein said heat radiating means comprises a heat conductive member and a heat exchange member provided on said heat conductive member, and one end of said heat conductive member contacts said polygon motor side. A heat radiation fin is formed on the other end of the heat conductive member, one end of the heat exchange member is fixedly contacted with the other end of the heat conductive member, and the other end is a heat radiation environment area. A polygon motor unit that has been extended to 5. A polygon motor unit, an imaging optical system and a mirror for guiding light from the polygon motor unit to form an image on a surface to be scanned, and the polygon motor unit, the imaging optical system and the mirror are held. An optical scanning device comprising a housing, wherein the polygon motor unit according to claim 1 is
An optical scanning device, wherein the optical scanning device is attached to a groove-shaped flow path for introducing outside air formed on an outer surface of the housing, and the heat radiating means is located in the flow path. 6. An optical scanning device according to claim 5, wherein the charged image carrier is exposed to light from an optical scanning device to form an electrostatic latent image, and is used for image formation. An image forming apparatus comprising: