JP2001117035A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an image forming device compact and to prevent dust from adhering to a seal glass for dust-proofing by horizontally carrying paper. SOLUTION: Photosensitive material 40 is scanned and exposed by deflecting a laser beam emitted from a light source to scan through optical parts provided in a hermetically sealed housing 16. An emitting port 42 through which the laser beam is nearly horizontally emitted is formed on the housing 16 and shielded by the seal glass 36 in erect posture. Therefore, even when the dust infiltrates into the housing 16, the dust is hardly retained because the seal glass 36 is erected, whereby an image defect is hardly caused. The laser beam transmitted through the seal glass 36 is nearly horizontally emitted and reflected in a vertical direction by a reflection mirror 38. Therefore, the scanned and exposed material 40 is carried in a horizontal direction, so that the image forming device is designed to be compact and the feeding accuracy of the photosensitive material is guaranteed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical scanning device used for an image forming apparatus such as a laser printer and a digital copying machine.

[0002]

2. Description of the Related Art In a writing method based on laser scanning exposure, the paper to be written is not affected by its own weight or the like when it is horizontally conveyed, so that the feeding accuracy is improved. However, in order to scan and expose a sheet conveyed in the horizontal direction, FIG.
As shown in the figure, a laser beam must be emitted from the optical scanning device 66 in the vertical direction.

For this reason, the housing 6 of the optical scanning device 66
8, an emission port 70 that opens downward is formed.
The seal glass 72 shields dust so that dust does not enter the housing 68 from the emission port 70 and adhere to optical components (such as the polygon mirror 76 and the return mirror 74).

However, even if the housing 68 has a sealed structure, dust may enter the inside of the housing 68. If the surface of the seal glass 72 is horizontal, the dust easily stays in the seal glass 72, and the dust kicks the laser beam. This causes image defects.

[0005] For this reason, it is conceivable that an emission port is opened on the side surface of the housing and the emission port is shielded by a seal glass in an upright posture as a configuration for emitting a laser beam horizontally. However, with this configuration, it is necessary to convey the paper in the vertical direction, the accuracy of feeding the paper is degraded, and it is necessary to provide a conveyance mechanism beside the optical scanning device, which increases the size of the image forming apparatus. I will.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. The present invention aims at reducing the size of an image forming apparatus by transporting paper horizontally, and preventing dirt from adhering to a dust-proof seal glass. The task is to

[0007]

According to the first aspect of the present invention, a photosensitive material is scanned and exposed by deflecting and scanning a laser beam generated from a light source via an optical component provided in a closed housing. . The housing has an emission port for emitting the laser beam substantially horizontally, and the emission port is shielded by a transparent plate in an upright posture. Therefore, even if dust enters the sealed housing, the transparent plate stands upright, so that the dust hardly stays and image defects hardly occur.

[0008] The laser beam transmitted through the transparent plate is emitted substantially horizontally, and is turned vertically by the reflection mirror. Therefore, the photosensitive material to be scanned and exposed can be transported in the horizontal direction, so that the image forming apparatus can be designed to be compact,
The feeding accuracy of the photosensitive material is also guaranteed. In addition, since the housing has a hermetically sealed structure, it is not necessary to employ an internal pressurization method, so that a fan or a filter is not required, and the manufacturing cost can be reduced.

According to the second aspect of the present invention, the reflection mirror is the last mirror of the optical component mounted on the base surface of the housing. That is, by adopting a configuration in which the final mirror is taken out of the housing, a special device for separately attaching a reflecting mirror is not required, and the optical axis can be easily adjusted.

According to the third aspect of the present invention, the periphery of the reflection mirror and the transparent plate is pressurized by the pressurizing means so that dust around the reflection mirror and the transparent plate do not approach the reflection mirror and the transparent plate.

According to the fourth aspect of the present invention, the reflection mirror is surrounded by the cover, and the opening of the cover can be opened and closed by the shutter. With this configuration, when the laser beam is not emitted, the shutter is closed to minimize the chance of dust adhering to the reflection mirror.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical scanning device according to an embodiment will be described below with reference to the drawings. (Schematic Configuration of Optical Scanning Apparatus) As shown in FIG. 1, a housing 16 of the optical scanning apparatus 14 is attached to a main body frame of the image forming apparatus. The upper opening of the housing 16 is substantially sealed with the cover 20 sandwiching the sponge 18, so that dust and the like do not enter the inside of the housing 16.

Optical components are housed in this closed space. In the optical system formed by this optical component, a laser beam emitted from a laser diode reaches a polygon mirror 24 via a collimator lens, a cylinder lens, and the like. The polygon mirror 24 is a polygonal prism having a plurality of mirror surfaces on a side surface, and is rotated at a high speed by a scanner motor.

By the deflection of the polygon mirror 24, the laser beam obtains a swing angle, and the Fθ lens 26,
8. Exposure scanning is performed on the photosensitive material 40 via the folding mirrors 32 and 34, the dust-proof seal glass 36, and the reflection mirror 38. The laser diode controls the light emission amount and the light emission time by a laser diode driver substrate, modulates the laser diode according to an image signal from the image forming apparatus, and records an image on the photosensitive material 40.

On the other hand, the housing 16 has an upper bottom plate 16A.
And a lower bottom plate 16B, and an emission port 42 through which a laser beam passes is formed on a horizontal wall that separates the upper bottom plate 16A and the lower bottom plate 16B. The emission port 42 is covered with the seal glass 36 in an upright posture.

On the lower surface of the upper bottom plate 16A, a reflection mirror 38 as a final mirror of the optical system is mounted on the outside of the housing 16, so that the laser beam passing through the seal glass 36 in a substantially horizontal direction is moved in a vertical direction. Wrapped around
The photosensitive material 40 being conveyed in the horizontal direction is reached.

Further, the reflection mirror 38 and the seal glass 36 are surrounded by a cover 46, and a laser beam is emitted downward from an opening 48 formed on the lower surface of the cover 46.

A shutter 50 is provided in the opening 48. The end of the shutter 50 is attached to the edge of the opening 48 via a hinge 52. A rod 56 of a cylinder 54 is rotatably connected to the shutter 50 by a pin 58. And at the time of image formation,
In this configuration, the cylinder 50 is driven to contract the rod 56, and the shutter 50 is opened so as not to block the laser beam.

A fan 60 is provided on the right wall of the cover 46.
Is installed. Also, on the outlet side of the fan 60,
An air filter 62 is attached, and clean air is caused to flow into the cover 46 to form an airflow toward the opening 48 to pressurize the inside of the cover 46.

Next, how the seal glass is dust-proofed in the optical scanning device of this embodiment will be described.

During image formation, the cylinder 54 is driven to open the shutter 50. At this time, since the clean air flows into the opening 48 by the fan 60 and the inside of the cover 46 is pressurized, dust does not enter through the opening 48. Therefore, the reflection mirror 38 and the seal glass 36
No dust adheres to the surface. Also, even if dust enters the hermetically sealed housing 16 through the gap in the cover 20, the seal glass 36 is upright, so that dust does not stay and image defects are unlikely to occur.

In the present embodiment, the shutter 50 is opened and closed by the cylinder 54. However, the shutter 50 may be opened by the airflow pressure of the fan 60.
In this case, the closing operation of the shutter 50 is performed by a spring that biases the shutter 50 in the closing direction.

The laser beam that has passed through the seal glass 36 is emitted substantially horizontally, is turned vertically by the reflection mirror 38, is emitted from the opening 48, and scans the photosensitive material 40 by exposure. Therefore, the photosensitive material 40 can be transported in the horizontal direction, so that the image forming apparatus can be designed to be compact,
The feeding accuracy of the photosensitive material 40 is also guaranteed. The optical scanning device according to the present embodiment can also be used in a copying machine or the like that forms a latent image on a photosensitive drum with a laser beam, develops the latent image with toner, and transfers the developed image to paper.

In this embodiment, the final reflection mirror 38 is used.
Is mounted on the upper bottom plate 16A of the housing 16, so that no special device is required for mounting the reflection mirror, and the optical axis can be easily adjusted.

Further, the reflection mirror 38 and the seal glass 3
Although a fan 60 for pressurizing the periphery of 6 and a cover 46 surrounding the reflection mirror 38 and the seal glass 36 are provided, the seal glass 36 may be in an upright posture as shown in FIG. This can prevent dust from adhering.

[0026]

According to the present invention, the image forming apparatus can be made compact by transporting the paper horizontally. Also, no dirt adheres to the dust-proof seal glass.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an optical scanning device according to an embodiment.

FIG. 2 is a side sectional view showing the optical scanning device according to the embodiment.

FIG. 3 is a side sectional view showing a modified example of the optical scanning device according to the embodiment.

FIG. 4 is a side sectional view showing a conventional optical scanning device.

[Explanation of symbols]

 36 Seal glass (transparent plate) 38 Reflecting mirror 42 Exit port 46 Cover 48 Opening 50 Shutter 60 Fan (pressurizing means)

Claims (4)

[Claims] 1. An optical scanning device for deflecting and scanning a laser beam generated from a light source through an optical component provided in a sealed housing to scan and expose a photosensitive material, wherein the laser beam formed on the housing is provided. An optical scanning device, comprising: an emission port that emits light substantially horizontally; a transparent plate that shields the emission port in an upright posture; and a reflection mirror that folds a laser beam emitted substantially horizontally in a vertical direction. . 2. The optical scanning device according to claim 1, wherein the reflection mirror is a final mirror of the optical component mounted on a base surface of the housing. 3. The optical scanning device according to claim 1, further comprising a pressure unit configured to press around the reflection mirror and the transparent plate. 4. The optical scanning device according to claim 1, wherein the reflection mirror is surrounded by a cover, and an opening of the cover can be opened and closed by a shutter.