JPH0634908A - Optical writer for electrophotographic device - Google Patents

Abstract

PURPOSE:To prevent the mirror surfaces of a polygon mirror from varying in a reflection factor in a main scanning direction by preventing powdery dust from sticking partially on the mirror surfaces. CONSTITUTION:Fins 40 which extend almost from the longitudinal center of the respective mirror surfaces to the corner parts 30b of the polygon mirror 30 are fitted to the peripheral edge parts of both plate surfaces 30c of the polygon mirror 30. The fins 40 has their surfaces slanted gradually leaving the plate surfaces 30c of the polygon mirror 30 in the rotating direction. Then when the polygon mirror 30 is rotated, the flow of air is guided by the fins 40 from one rotation-directional end to the opposite end on the mirror surfaces 30a as shown by an arrow to be made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic system (a system for transferring an image formed on a photoconductor to a sheet for recording) using a laser, such as a printer, a copying machine and a facsimile. It can be applied to an electrophotographic apparatus for recording on a sheet. Specifically, in such an electrophotographic apparatus, a plate-shaped polygon mirror is rotated to reflect light from a light source on a mirror surface on the outer periphery of the polygon mirror, and the reflected light is applied to a photoconductor to expose the photoconductor. The present invention relates to an optical writer that writes on the body.

[0002]

2. Description of the Related Art Conventionally, since this type of optical writer does not like dust, a housing having a high airtightness is used as a housing for housing optical parts such as a polygon mirror. In a clean room.

[0003]

However, since toner, paper dust, dust in the air, and the like are suspended in the laser printer in which the optical writer operates, a very small amount of dust is inevitable. Invade inside.

Then, in a situation where dust drifts, polygon mirror
When the dew condensation occurs on the mirror surface, the dust may adhere to the mirror surface due to dew condensation, and even if the water evaporates thereafter, the dust may remain adhered. In such a case, as shown in FIG. 24, when the polygon mirror-1 is rotated counterclockwise in the drawing at a high speed, a relative air flow with respect to each mirror surface 1a is generated as shown by the arrow, and the mirror surface is shown. The rotational end in 1a is
Since it becomes the shadow of the corner of the polygon mirror-1, that part becomes a negative pressure, and dust is likely to be involved. On the other hand, each mirror
At the end of the surface 1a in the direction opposite to the rotation direction, a positive pressure is applied, and the dust is easily blown off.

Therefore, as shown in the figure, a large amount of dust K adheres to the widthwise center of the mirror surface 1a at the end of each mirror surface 1a in the direction of rotation, and at the end opposite to the direction of rotation, its width is not shown. Slightly adheres to both ends in the direction. Moreover, the laser beam upon entering the polygon mirror-1 still has a large beam diameter and has a distribution S in which light is concentrated in the center, as shown in FIG. Therefore, there is a problem that the adhesion of the dust K has a great influence, and the reflectance of the mirror surface 1a is different between the rotation direction end of the polygon mirror-1 and its opposite end.

Further, the dust that has not adhered to the mirror surface 1a is circumscribed by the polygon mirror -1 as shown by the arrow by the air flow caused by the counterclockwise rotation of the polygon mirror-1 as shown in FIG. It is repelled in the tangential direction of the circle. The polygon mirror -1 is often configured around the polygon as shown in the figure, and the dust is more likely to be attached to the portion shown by the chain double-dashed line in the figure, where the dust is blown away at a shorter distance or at a blow-off portion.

In the vicinity of the fθ lens 2, the airflow is vertically divided by the lens closest to the polygon mirror-1, but the fθ lens 2 is provided in the housing 3 of the optical writer as shown in FIG. Since it is fixed to the pedestal 4 by the pressing member 6 via the leaf spring 5 and the like, a small gap is formed around the lens, and that portion becomes a blister, which deteriorates the air flow. Therefore, there is a problem that dust easily adheres to the polygon mirror-1.

Incidentally, in the experiment, the changes in the reflectance of the polygon mirror-1 and the transmittance of the fθ lens 2 were as follows. Rotation direction end Center opposite end Polygon mirror -20% -12% -7% fθ lens -8% -12% -12% Overall -27% -23% -18% Therefore, in the optical writer When dust enters, the beam power in the main scanning direction changes as shown in the graph of FIG. Therefore, the formation of a latent image is hindered, and for example, a method called a positive-positive process (or background lighting) has a problem that background stain is likely to occur on the writing end side of an image.

Therefore, an object of the present invention is to prevent dust from being unevenly attached to the mirror surface of the polygon mirror and to prevent the reflectance on the mirror surface from fluctuating in the main scanning direction. .

[0010]

Therefore, according to the first aspect of the present invention, a plate-shaped polygon mirror 30 is rotated to emit light from a light source 32, as in the embodiments shown in FIGS. 1 to 4 below. The light is reflected by the mirror surface 30a on the outer periphery of the polygon mirror, and the reflected light is applied to the photoconductor 11, and the photoconductor 11
In the optical writer 16 of the electrophotographic apparatus for writing on the upper surface, the fins 40 that make the air flow on the mirror surface 30a uniform are provided with the fins 40 on the plate surface 30c of the polygon mirror 30.
It is characterized by being attached to.

According to a second aspect of the present invention, for example, as shown in the embodiment shown in FIG. 7 below, a plate-shaped polygon mirror 30 is rotated so that the light from the light source is reflected on the outer surface of the polygon mirror. 30a, the reflected light is applied to the photoconductor 11,
An optical writer 16 of an electrophotographic apparatus for writing on the photoconductor 11 is provided with a blower device 45 and a blower guide 46 for forming an air curtain surrounding the polygon mirror 30. .

According to a third aspect of the present invention, a plate-shaped polygon mirror is used, for example, as in the embodiments shown in FIGS. 8 and 9 below.
30 is rotated to reflect the light from the light source on the mirror surface 30a on the outer periphery of the polygon mirror, and the reflected light is reflected by the fθ lens 3
In the optical writer 16 of the electrophotographic apparatus for writing on the photoconductor 11 through 4 through 4, the pedestal 50 of the fθ lens 34 forms an outflow path 51 through which air from the polygon mirror 30 flows out. A guide 53 for guiding the air to the outflow path 51 is provided while being formed.

In the optical writer 16 of the electrophotographic apparatus according to any one of claims 1 to 3, the one described in claim 4 is, for example, as shown in the following illustrated embodiment, in the middle of the air flow. The dust member 43 is provided.

According to a fifth aspect of the present invention, for example, as in the embodiments shown in FIGS. 10 to 12 below, a plate-shaped polygon mirror 30 is rotated so that the light from the light source is reflected by the polygon mirror.
It is reflected by the outer mirror surface 30a, and the reflected light is reflected by the photoconductor 1.
In the optical writer 16 of the electrophotographic apparatus for writing on the photosensitive member 11, the polygon mirror 30
The plate surface 30c is formed into a mortar-shaped concave shape, and
The air guide member 5 facing the plate surface 30c with a constant gap.
7 is provided.

According to a sixth aspect of the present invention, for example, as in the embodiments shown in FIGS. 13 and 17 below, a plate-shaped polygon mirror 30 is rotated so that the light from the light source is reflected by the polygon mirror 30.
It is reflected by the outer mirror surface 30a, and the reflected light is reflected by the photoconductor 1.
In the optical writer 16 of the electrophotographic apparatus for writing on the photosensitive member 11, the polygon mirror 30
The plate surface 30c is formed in a conical or pyramidal convex shape, and an air guide member 57 that faces the plate surface 30c with a constant gap is provided.

According to a seventh aspect of the invention, in the optical writer 16 of the electrophotographic apparatus according to the fifth or sixth aspect, for example, as in the following illustrated embodiment, the plate surface 30c is radially radiated from the center. A plurality of ribs 55 extending to
It is characterized by

[0017]

When the polygon mirror 30 is rotated, the fins 40 make the air flow on the mirror surface 30a uniform.

According to the second aspect of the present invention, the polygon mirror 30 is rotated to reflect the light from the light source 32 on the mirror surface 30a on the outer periphery of the polygon mirror, and the reflected light is applied to the photoconductor 11. When writing is performed on the photoconductor 11, an air curtain surrounding the polygon mirror 30 is formed by the air blower 45 and the air blow guide 46.

In the third aspect, when the polygon mirror 30 is rotated, the air flow generated by the rotation of the polygon mirror 30 is guided to the outflow passage 51 by the guide 53.

According to the fourth aspect of the present invention, when the polygon mirror 30 is rotated to write on the photoconductor 11, the dust collecting member 43 removes dust contained in the air.

According to the fifth aspect of the present invention, when the polygon mirror 30 is rotated, the flow of air generated by the rotation of the polygon mirror 30 is guided by the plate surface 30c and the air guide member 57, and the polygon mirror 30 is guided. It guides to the outer peripheral direction of 30 diagonally upward or downward.

In the sixth aspect of the present invention, when the polygon mirror 30 is rotated, the flow of air generated by the rotation of the polygon mirror 30 is guided to the outer peripheral direction by the plate surface 30c and the air guide member 57.

According to the seventh aspect, the rib 5 is
The air flow generated by the rotation of the polygon mirror 30 by scratching at 5 is sent radially toward the outer circumference.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 19 is an overall schematic configuration diagram of a laser printer including an optical writer according to the present invention. Reference numeral 10 in the figure indicates the apparatus main body. In the device body 10,
A belt-shaped photoconductor 11 is provided at approximately the center. Around the photoconductor 11, a charging device 12, a developing device 13, a transfer device 14, a cleaning device 15, and the like are arranged in order in the driving direction indicated by the arrow. An optical writer 16 is provided above the photoconductor 11, and the paper feed cassette 1 is provided near the bottom of the apparatus body 10.
Attach 7 detachably.

Then, the sheet fed in the direction of arrow A from the sheet feeding cassette 17 is conveyed to the photoconductor 11 by the registration roller pair 18 at a timing. Photoconductor 1
1 is rotationally driven in the clockwise direction, at which time the charging charger 1
The surface is uniformly charged by 2 and the laser light from the optical writing device 16 is irradiated to form an electrostatic latent image on the photoconductor 11. This latent image is visualized by a toner as it passes through the developing unit 13, and this visible image is transferred to the photoreceptor 11 by a sheet.
The visible image on the sheet, which is transferred to the sheet by the transfer charger 14, is fixed by the fixing device 19. And
The sheet exiting the fixing device 19 is transported by a transport roller pair 20.

The sheet passing through the pair of transport rollers 20 is discharged in the direction of arrow B with the image surface facing upward according to the direction switching by the switching claw 21, or passes through the sheet transport path 22. And is conveyed in the direction of arrow C by the pair of paper discharge rollers 23 and is discharged to the paper discharge unit 24 on the apparatus main body 10 with the image surface facing downward. On the other hand, the residual toner on the photoconductor 11 after transfer is removed by the cleaning device 15.

For writing on the photoconductor 11 by the optical writer 16, as shown in FIG. 18, while rotating the polygon mirror 30 having a polygonal plate shape with the motor 31, the light from the light source 32 is converted into a cylindrical lens. Polygon mirror through 33
The light is reflected by the mirror surface 30a by hitting the mirror surface 30a on the outer periphery of the mirror 30. Then, the reflected light is reflected by the fθ lens 34.
Through 1st Miller 35, 2nd Miller 36, 3rd Miller
The light is reflected on the reflection surface of 37, is applied to the photoconductor 11 through the dustproof glass 38, and is scanned in the main scanning direction to write on the photoconductor 11. Further, a part of the light reflected by the reflecting surface of the second mirror 36 is put into the optical fiber 39 to perform synchronous detection of the optical writing start.

By the way, according to the first aspect of the present invention, as shown in FIGS. 1 and 2, each of the mirror surfaces 3 of the polygon mirror 30 is provided on the periphery of both plate surfaces 30c of the polygon mirror 30.
The fins 40 extending from the approximate center in the length direction 0a to the corners 30b at the ends of the polygon mirror 30 in the rotation direction are attached by adhesion or the like. The fin 40 is made of a non-magnetic metal, and its surface is gradually rotated in the rotation direction to form the plate surface 30 of the polygon mirror 30.
Tilt away from c.

When the polygon mirror 30 rotates, it is guided by the fins 40 to guide the air flow from the end of the mirror surface 30a in the direction of rotation to the opposite end, as shown by the arrow in FIG. Shed on.

In the above embodiment, a pair of fins 40 is provided on each plate surface 30c of the polygon mirror 30 for each mirror surface 30a, but as shown in FIGS.
A plurality of fins 40 may be continuously attached to only one plate surface 30c of 0. The fins 40 are made of the same non-magnetic metal as in the above embodiment, and the surface of each fin 40 is
The polygon mirror 30 is gradually inclined in the direction of rotation from one plate surface 30c of the polygon mirror 30 and rises, and the outer peripheral edge of each fin 40 is formed into a circular shape that forms a circumscribed circle of the polygon mirror. For the attachment, the fins 40 may be formed one by one and attached to the polygon mirror 40 by adhesion or the like, or the fins 40 may be connected in series to form an annular shape.

When the polygon mirror 30 rotates, the air flow is guided by the fins 40 from one plate surface 30c side to the other plate surface 3 as shown by the arrow in FIG.
It is led to the 0c side, and it is made to flow uniformly across the mirror surface 30a in the axial direction of the polygon mirror 30.

Further, in the above-described embodiment, as shown in FIG. 5 or 6, a filter cartridge 42 detachably attached to the upper lid 16b may be provided in the housing 16a of the optical writer 16. This filter cartridge 4
2 has an annular filter 42a whose center lies on the axis of the polygon mirror 30.
A dust collecting member 43 is attached to a. 5 shows a case where the filter 42a is provided on the upper side of the polygon mirror 30, and FIG. 6 shows a case where the filter 42a is provided on the lower side.

When the polygon mirror 30 rotates, the air flowing in the axial direction of the polygon mirror 30 from above the mirror surface 30a by the fins 40 is passed through the filter cartridge 42 into the dust collecting member 43. Remove the dust.

Further, in the second aspect, as shown in FIG. 7, the fan chamber 44 is provided in which the upper lid 16b of the housing 16a is projected upward and is partitioned by the partition wall 16c. Then, on the fan chamber 44, the blower device 45 provided with the fan 45a in the fan chamber 44 is attached.
The rotation axis of 5a is provided on the same line as the rotation axis of the polygon mirror 30. The partition wall 16c is provided with an air intake port 16d which communicates with the inside of the housing 16a, and an outlet port 16e directed toward the outer periphery of the polygon mirror 30. A blower guide 46 for guiding the blown air from the fan 45a to the outlet is provided in the fan chamber 44, and a screen-like dust collecting member 43 is attached to the outlet 16e so as to cover the opening. .

Then, when the polygon mirror 30 is rotated, the fan 45 is driven to take in the air in the housing 16a from the air intake port 16d and guide it by the blower guide 46, and from the blowout port 16e through the dust collecting member 43 to the polygon. An air curtain is formed near the outer periphery of the mirror 30 to enclose the polygon mirror 30. At the same time, the dust in the air is removed by the dust collecting member 43.

Further, according to the third aspect, as shown in FIGS. 8 and 9, the pedestal 50 of the fθ lens 34 is formed into a rib shape in which the tangent line of the circumscribed circle of the polygon mirror 30 is extended in the rotational direction. Of the three lenses 34a, 34b, 34c forming the fθ lens 34, the polygon mirror-3
A guide 53 is provided between the upper surface of the lens 34a closest to 0 and the pressing spring 52 for fixing the lens 34a, and the polygon mirror 30 side is inclined so as to be separated from the lens 34a.

The guide 53 is formed by the lenses 34a and 34a.
b. 34c, and each lens 34a. 3
A sheet or the like may be sandwiched between the 4b and 34c and the pedestal 50 to prevent air from wrapping around around the transparent surfaces of the lenses 34b and 34c on the downstream side of the flow. Further, an adhesive sheet-like dust collecting member 43 may be provided along the inner surface of the housing 16a in the outflow passage 51.

When the polygon mirror 30 is rotated, the flow of air generated by the rotation of the polygon mirror 30 is guided to the outflow passage 51 by the guide 53 to flow out. Further, at that time, the dust collecting member 43 removes dust contained in the air.

Further, according to the fifth aspect, in FIG.
As shown in, the upper and lower plate surfaces 30c of the polygon mirror 30
Is formed into a mortar-shaped concave shape, and the optical writer 1
The housing 16a of No. 6 is provided with an air guide member 57 that faces both plate surfaces 30c with a constant gap t. On the plate surface 30c of the polygon mirror 30, as shown in FIG.
A plurality of substantially arc-shaped ribs 55 extending radially from the center are provided. The rib 55 is formed to have a constant height, as shown in FIG. 12, with its arcuate outer surface facing the direction of rotation of the polygon mirror 30 shown by the arrow in the figure. As a method of forming this, a mortar-shaped member 56 having these is integrally molded with a chargeable plastic and attached to the upper and lower surfaces of the polygon mirror main body 30e by adhesion or the like. On the other hand, the wind guide member 57
As shown in FIG. 10, a ventilation port 58 is provided at a position corresponding to the center of the plate surface 30c.

When the polygon mirror 30 rotates, the rotation of the polygon mirror 30 guides the flow of air generated between the plate surface 30c and the air guide member 57 along the ribs 55, as shown by arrows in FIG. The air is sent to an area away from the light scanning area.

According to the sixth aspect of the present invention, FIG.
As shown in, the upper plate surface 30c of the polygon mirror 30
Is formed in a pyramidal shape, and a pyramidal air guide member 57 facing the plate surface 30c with a constant gap t is fixed to the polygon mirror 30 above the plate surface 30c. Provided integrally with -30. As shown in FIG. 14, the plate surface 30c of the polygon mirror 30 is formed in an octagonal pyramid shape having a divided surface 30d corresponding to the eight mirror surfaces 30a, and each divided surface 30d and each mirror surface 30a. The connecting portion with and is chamfered to form a rounded curved surface.
Then, on each of the divided surfaces 30d, ribs 5 extending radially from the center side of the plate surface 30c to the mirror surface 30a.
5 is provided as shown in FIG. The rib 55 has a substantially arcuate shape, and the outer side of the arcuate shape is formed at a constant height in the rotation direction of the polygon mirror 30 shown by the arrow in the figure.

Further, the air guide member 57 is formed so that its peripheral edge is located slightly below the connecting portion between the mirror surface 30a and the dividing surface 30d, and the position corresponding to the central portion of the plate surface 30c. A ventilation port 58 is provided in the.

When the polygon mirror 30 rotates, the plate surface 30 is rotated by the rotation as shown by the arrow in FIG.
The flow of air generated between c and the baffle member 57 is guided along the ribs 55, flows from the upper side to the lower side of the mirror surface 30a, and blows off over the mirror surface 30a.

In the embodiment shown in FIGS. 13 to 15, the upper plate surface 30c of the polygon mirror 30 is formed in an octagonal pyramid shape, and the baffle member 57 is provided integrally with the polygon mirror 30. However, the configuration shown in FIGS. 16 and 17 may be adopted. That is, the upper plate surface 30c of the polygon mirror 30 is formed into a conical shape. Then, on the conical plate surface 30c, ribs 55 similar to those described above are provided radially from the center side of the plate surface 30c toward the upper edge of the ridge between the mirror surfaces 30a and 30a.

On the other hand, on the upper surface of the flange 61 provided on the polygon motor 60, as shown in FIG.
A conical baffle member 57 is provided so as to face the plate surface 30c of 30 with a constant gap t. The baffle member 57 is formed so as to cover the entire polygon mirror 30, and the mirror surface 30 is formed.
A window 59 is provided in a portion facing a. Then, the window 59 is enlarged on the side for performing the optical writing so as not to interfere with the optical writing, and is reduced on the other side to reduce the air guide member 57.
Give strength to.

Further, the ventilation port 5 is provided at a position corresponding to the central portion of the plate surface 30c of the polygon mirror 30 in the air guide member 57.
8 is provided. A filter cartridge 62 is detachably provided between the cover 16b of the housing 16a and the baffle member 57 in the vent hole 58.

When the polygon mirror 30 rotates, the plate surface 30 is rotated by the rotation as shown by the arrow in FIG.
Air is sucked through the filter cartridge 60 and the ventilation hole 58 by the flow of air generated between the air c and the baffle member 57. At that time, the filter cartridge 60 removes dust contained in the air. Then, the flow of the air is guided along the ribs 55, flows from the upper side to the lower side of the mirror surface 30a, blows off the mirror surface 30a, and is sent out from the window 59.

In this case, as compared with the case where the air guide member 57 is integrally provided with the polygon mirror 30 as described above, the gap between each mirror surface at the air blowing position is not constant and the air blowing position is different at each air blowing position. The air flow is not uniform. However, since the air guide member 57 does not rotate, the air flow generated by the air guide member 57 is not generated, and the air flow due to the rotation of the polygon mirror 30 is not disturbed and flows smoothly.

[0049]

Therefore, according to the first aspect of the present invention, when the polygon mirror is rotated, the flow of air flowing on the mirror surface is made uniform by the fins, so that dust is generated by the polygon mirror. It is prevented that the reflectance on the mirror surface fluctuates in the main scanning direction by preventing uneven adhesion on the surface.

According to the second aspect of the present invention, the polygon mirror is rotated so that the light from the light source is reflected by the mirror surface of the outer periphery of the polygon mirror, and the reflected light is applied to the photoconductor, and the photoconductor is exposed. When writing on the body, the air blower and the air blower guide form the air curtain surrounding the polygon mirror, so
The dust is prevented from adhering to the mirror surface of the polygon mirror to prevent the reflectance on the mirror surface from fluctuating.

According to the third aspect of the present invention, when the polygon mirror is rotated, the air flow generated by the rotation of the polygon mirror is guided to the outflow passage by the guide.
The air smoothly flows so that dust is not biasedly adhered to the fθ lens surface to prevent the transmittance on the lens surface from fluctuating in the main scanning direction.

According to the fourth aspect of the present invention, since the dust contained in the air is removed by the dust collecting member, the dust floating in the optical writer is reduced, and the dust is the mirror surface of the polygon mirror. Or fθ is reduced to adhere to the lens surface to prevent the reflectance on the mirror surface and the transmittance on the lens surface from fluctuating.

According to the fifth aspect of the present invention, when the polygon mirror is rotated, the air flow generated by the rotation of the polygon mirror is guided by the plate surface of the polygon mirror and the air guide member, and the polygon mirror is guided. Since it is guided obliquely upward or obliquely downward in the outer peripheral direction of the mirror, dust is prevented from adhering to the mirror surface and the reflectance on the mirror surface is prevented from fluctuating in the main scanning direction.

According to the sixth aspect of the present invention, when the polygon mirror is rotated, the air flow generated by the rotation of the polygon mirror is surrounded by the convex plate surface of the polygon mirror and the air guide member. Since the particles are guided in the direction, the dust that tends to adhere to the mirror surface is blown away, and the reflectance on the mirror surface is prevented from fluctuating in the main scanning direction.

According to the seventh aspect of the present invention, the ribs scratch the air between the plate surface of the polygon mirror and the air guide member and guide the air from the center of the plate surface toward the outer periphery. The flow of air generated by the rotation of − can be made stronger.

[Brief description of drawings]

FIG. 1 is a front view of a polygon mirror in an optical writer of a laser printer which is an embodiment of the present invention.

FIG. 2 is a plan view thereof.

FIG. 3 is a front view showing another example of the polygon mirror.

FIG. 4 is a plan view thereof.

FIG. 5 is a configuration diagram showing another embodiment of the present invention in which a filter is provided on the upper side of the polygon mirror.

FIG. 6 is a configuration diagram showing another embodiment of the present invention in which a filter is provided below the polygon mirror.

FIG. 7 is a configuration diagram showing another embodiment of the present invention in which an air blower for forming an air curtain surrounding the polygon mirror and an air blow guide are provided.

FIG. 8 is a configuration diagram showing another embodiment of the present invention in which an air outflow passage and a guide are provided in the fθ lens.

FIG. 9 is a plan view thereof.

FIG. 10 is a constitutional view showing another embodiment of the present invention in which the plate surface of the polygon mirror is made concave and an air guide member facing the plate surface is provided.

FIG. 11 is a plan view of the polygon mirror.

FIG. 12 is a vertical sectional view thereof.

FIG. 13 is a constitutional view showing another embodiment of the present invention in which the plate surface of the polygon mirror has a pyramidal convex shape and an air guide member facing the plate surface is provided.

FIG. 14 is a plan view thereof.

FIG. 15 is a sectional view taken along the line EE.

FIG. 16 is a constitutional view showing another embodiment of the present invention in which the plate surface of the polygon mirror has a pyramidal convex shape and an air guide member facing the plate surface is provided.

FIG. 17 is a plan view thereof.

FIG. 18 is an explanatory diagram showing writing on a photoconductor in the optical writing device of the present invention.

FIG. 19 is an overall schematic configuration diagram of a laser printer including the optical writer.

FIG. 20 is a graph showing a state in which the beam power at the time of writing on the photosensitive member in the conventional laser printer fluctuates in the main scanning direction.

FIG. 21 is a sectional view of the vicinity of a polygon mirror and an fθ lens in an optical writer of a conventional laser printer.

FIG. 22 is a plan view thereof.

FIG. 23 is an explanatory view showing the distribution of the light intensity of the laser beam when it is incident on the mirror surface of the polygon mirror.

FIG. 24 is an explanatory view showing a state in which dust is attached to a mirror surface in a conventional polygon mirror.

[Explanation of symbols]

 11 Photoconductor 16 Optical Writer 30 Polygon Mirror 30a Mirror Surface 30c Plate Surface 34 fθ Lens 40 Fin 43 Dust Collection Member 45 Blower Device 46 Blower Guide 50 Pedestal 51 Outflow Channel 53 Guide 55 Rib 57 Blower Member t Gap

Claims (7)

[Claims] 1. A plate-shaped polygon mirror is rotated to reflect light from a light source on a mirror surface of an outer periphery of the polygon mirror,
In the optical writer of an electrophotographic apparatus which applies the reflected light to a photoconductor and writes on the photoconductor, fins for uniformizing the flow of air flowing on the mirror surface are provided on the plate surface of the polygon mirror. An optical writer for an electrophotographic device that is attached. 2. A plate-shaped polygon mirror is rotated to reflect light from a light source on a mirror surface on the outer periphery of the polygon mirror,
An optical writer for an electrophotographic apparatus, which applies the reflected light to a photoconductor and writes on the photoconductor, comprises an air blower for forming an air curtain surrounding the polygon mirror and a blower guide. Optical writer for photographic equipment. 3. A plate-shaped polygon mirror is rotated to reflect light from a light source on a mirror surface on the outer periphery of the polygon mirror,
In the optical writer of an electrophotographic apparatus that applies the reflected light to a photoconductor through an fθ lens and writes on the photoconductor, a pedestal of the fθ lens forms an outflow path for outflowing air from the polygon mirror. An optical writer for an electrophotographic apparatus, which is also provided with a guide for guiding air to the outflow passage. 4. The optical writer for an electrophotographic apparatus according to claim 1, wherein a dust collecting member is provided in the middle of the flow of air. 5. A plate-shaped polygon mirror is rotated to reflect light from a light source at a mirror surface on the outer periphery of the polygon mirror,
In the optical writer of an electrophotographic apparatus which applies the reflected light to a photoconductor and writes on the photoconductor, the plate surface of the polygon mirror is formed into a mortar-shaped concave shape and is constant with the plate surface. An optical writer for an electrophotographic apparatus, which is provided with air guide members facing each other across a gap. 6. A plate-shaped polygon mirror is rotated to reflect light from a light source on a mirror surface on the outer periphery of the polygon mirror,
In the optical writer of an electrophotographic apparatus that applies the reflected light to a photoconductor and writes on the photoconductor, the plate surface of the polygon mirror is formed into a conical or pyramidal convex shape, and the plate surface and An optical writer for an electrophotographic apparatus, which is provided with air guide members facing each other with a constant gap. 7. The optical writer for an electrophotographic apparatus according to claim 5, wherein the plate surface is provided with a plurality of ribs extending radially from the center.