JPH0534610A - Exposing device for electrophotographic copying device - Google Patents

Abstract

PURPOSE:To offer an exposing device for an electrophotographic copying device in which a scanning reference position detecting sensor and a laser beam can take a positional relation faultless precision, and which can accurately scan. CONSTITUTION:As to the exposing device for an electrophotographic copying device in which a laser beam projecting means 31, and a beam scanning means 32, a scanning reference position detecting means 36 for converting the laser beam into an electrical signal when the laser beam is inputted in order to detect the reference position in the scanning range of the beam scanning means 32 and outputting it, and a detected position fine adjustment means 40 for finely adjusting the positional relation between the scanning reference position detecting means 36 and the laser beam made incident on it are attached to a common frame 39; a window 38 for working to execute fine adjustment by the detected position fine adjustment means 40 is formed on the frame 39 by holing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure device of an electrophotographic apparatus for exposing a surface of a photoconductor to image light in the electrophotographic apparatus.

In an electrophotographic apparatus, an apparatus in which a semiconductor laser beam is scanned on the surface of a photoconductor is widely used.

[0003]

2. Description of the Related Art Generally, an exposure apparatus for an electrophotographic apparatus generally includes a laser diode for generating and emitting a semiconductor laser beam, a lens for focusing the laser beam on the surface of a photoconductor, and a laser beam for the surface of the photoconductor. Further, a polygon mirror for horizontally scanning, a scanning reference position detection sensor for detecting a reference position which is the starting point of the scanning range, and the like are attached to a common frame. Then, after finely adjusting the positional relationship between the scanning reference position detection sensor and the laser beam, the frame is fixed to the main body of the electrophotographic apparatus.

[0004]

However, if the frame is fixed to the main body of the electrophotographic apparatus after the positional relationship between the scanning reference position detecting sensor and the laser beam is finely adjusted, the tightening force of the screws may become uneven or the fixing may occur. The frame is distorted by the generated stress and the like, and as a result, the positional relationship between the scanning reference position detection sensor and the laser beam is displaced, the detection timing is misaligned and correct scanning is not performed, and an image formed on the photoconductor ( The quality of the electrostatic latent image sometimes deteriorated.

Therefore, the present invention provides an exposure apparatus for an electrophotographic apparatus in which a scanning reference position detection sensor and a laser beam can have a correct positional relationship without deviation and can perform accurate scanning. With the goal.

[0006]

In order to achieve the above object, the exposure apparatus of the electrophotographic apparatus of the present invention has a charged photoreceptor 1 as shown in FIG. 1 for explaining an embodiment.
Laser beam emitting means 31 for exposing the photosensitive member 1, a beam scanning means 32 for scanning the surface of the photoconductor 1 with the laser beam emitted from the laser beam emitting means 31, and a scanning by the beam scanning means 32. In order to detect the reference position of the range, a scanning reference position detecting means 36 which converts the laser beam into an electric signal and outputs the electric signal when the laser beam is incident, the scanning reference position detecting means 36 and the laser beam incident on the scanning reference position detecting means 36. In the exposure apparatus of the electrophotographic apparatus in which the detection position fine adjustment means 40 for finely adjusting the positional relationship of the above is attached to the common frame 39, the work window 38 for performing the fine adjustment by the detection position fine adjustment means 40.
Is formed in the frame 39.

A cover 49 for closing the working window 38 may be provided so as to be openable and closable with respect to the working window 38. In addition, the exposure apparatus of the electrophotographic apparatus of the present invention uses a laser beam emitting means 31 for exposing the charged photoreceptor 1 and a laser beam emitted from the laser beam emitting means 31 on the surface of the photoreceptor 1. A beam scanning means 32 for scanning upward, and a scanning reference position for converting the laser beam upon incidence to an electric signal and outputting the same in order to detect the reference position of the scanning range by the beam scanning means 32. Sub-frame 60 common to the detection means 36
It is characterized in that the sub-frame 60 is mounted on the main frame 59 fixed to the main body of the electrophotographic apparatus without being fixed.

A plurality of legs 6 are attached to the sub-frame 60.
1 may be provided so as to project downward, and the foot 61 may be placed on the bottom surface of the main frame 59.

[0009]

After the frame 39 to which the parts such as the scanning reference position detecting means 36 and the unit are attached is fixed to the main body of the electrophotographic apparatus, the tool is inserted from the work window 38 into the fine detecting position adjusting means 40 in the frame 39. Thus, the positional relationship between the scanning reference position detecting means 36 and the laser beam incident thereon can be finely adjusted. After the fine adjustment is completed, the work window 38 can be closed by the openable / closable cover.

Further, if parts and units such as the scanning reference position detecting means 36 are attached to the sub-frame 60 and the sub-frame 60 is placed without being fixed to the main frame 59, the sub-frame 60 will not be mounted. No distortion occurs.

Therefore, if the positional relationship between the scanning reference position detecting means 36 and the laser beam incident on it is finely adjusted in advance on the sub-frame 60, the positional relationship will be incorrect when incorporated in the main body of the electrophotographic apparatus. Does not occur.

[0012]

Embodiments will be described with reference to the drawings. Figure 2
1 shows a laser beam printer to which the present invention is applied.
However, the present invention can be applied to a copying machine, a facsimile device, and other electrophotographic devices.

In FIG. 2, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaner 7 are arranged around the photosensitive drum 1 rotating in the direction of the arrow, and the surface of the photosensitive drum 1 is arranged. However, it is first negatively charged by the corona discharge of the charger 2.

Next, when the surface of the photosensitive drum 1 is exposed to light corresponding to the image to be recorded, the potential of the exposed portion is lowered and an electrostatic latent image is formed on the surface of the photosensitive drum 1. It is formed. When this latent image area passes through the developing device 4, negatively charged toner (developer) adheres to the latent image area and development with the toner is performed.

On the other hand, the paper 8 on which the image is printed is supplied from the paper hopper 9 one by one to a position where it comes into contact with the toner image formed on the photosensitive drum 1. Also, the transfer device 5
Is installed on the back side of the sheet 8 below the photosensitive drum 1 so as to give a positive charge to the sheet 8. Therefore, the toner image formed on the surface of the photosensitive drum 1 is attracted by the positive charges of the paper 8 and transferred to it.

The paper 8 on which the toner image is transferred is fixed to the fixing device 1.
The sheet 1 is fixed on the sheet 8. The toner remaining on the surface of the photosensitive drum 1 that has transferred the toner onto the paper 8 is cleaned by the cleaner 7.

FIG. 1 is a plan view of an exposure apparatus according to the first embodiment of the present invention, and FIG. 3 is a side sectional view thereof. 31 in the figure
Is a laser diode that emits a laser beam (semiconductor laser), and emits a laser beam at a timing according to an image signal input from an image processing circuit (not shown).

Reference numeral 32 denotes a polygon mirror which is a polygonal mirror having a reflecting surface formed on its side surface. The polygon mirror 32 is driven to rotate by a motor (not shown), and the laser beam is reflected by the mirror surface, whereby the shaft of the photosensitive drum 1 is rotated. The surface of the photosensitive drum is horizontally scanned with the laser beam along the direction.

Reference numerals 33 and 34 denote correction lenses formed wide so that the laser beam scanned by the polygon mirror 32 and horizontally oscillated can be transmitted. The correction lenses 33 and 34 focus the laser beam on the surface of the photosensitive drum 1. Reference numeral 35 is a reflection mirror that reflects the laser beam so that the surface of the photosensitive drum 1 is irradiated perpendicularly.

Such parts and units are all box-shaped exposure apparatus frames 39 (hereinafter simply referred to as "frames 39").
The laser beam emitted from the laser diode 31 is focused and scanned on the surface of the photosensitive drum 1 to expose the photosensitive layer.

Reference numeral 36 denotes a horizontal synchronization detection sensor (scanning reference position detection) for detecting the start point of the scanning range of the laser beam which is horizontally swung by the rotation of the polygon mirror 32 and synchronized with the image signal. Means). The horizontal synchronization detection sensor 36 is fixed by screws inside the frame 39, and when the laser beam is incident, the light energy is converted into an electric signal and output.

The reference numeral 40 reflects a laser beam to be incident on the horizontal synchronization detection sensor 36, and changes the reflection angle to change the positional relationship between the horizontal synchronization detection sensor 36 and the laser beam. It is an adjusting device.

The detection position fine adjustment device 40 is provided at the starting point position of the scanning range, and is formed by vertically arranging a plane mirror 42 on a rotating plate 41 placed in close contact with the floor surface of the frame 39. There is. Then, by rotating the rotary shaft 43 as a center, the direction of the plane mirror 42 can be changed, and the reflection direction of the laser beam can be finely adjusted.

Further, an arcuate long groove 44 centering on the rotary shaft 43 is bored through the rotating plate 41, and a screw threaded through the long groove 44 and screwed onto the floor surface of the frame 39. By tightening 45, the rotating plate 41 is fixed to the frame 39.

The lid 39a of the frame 39 has a
A work window 38 is formed at a position facing the detection position fine adjustment device 40, and a tool such as a screwdriver is inserted into the frame 39 from the outside through the work window 38,
The detection position fine adjustment device 40 can be finely adjusted (that is, the direction of the plane mirror 42 is changed by a slight angle and the screw 45 is retightened).

Therefore, according to the apparatus of the above-described embodiment, after the frame 39 is firmly fixed to the main body of the electrophotographic apparatus, the positional relationship between the horizontal synchronization detection sensor 36 and the laser beam can be finally finely adjusted. I can.

The reference numeral 49 shown in FIG. 3 is a work window 3
It is an openable / closable cover for closing 8 and can be formed by, for example, an adhesive sheet or a rotating lid. Then, after the fine adjustment is completed, the work window 38 is closed,
It is possible to prevent dust and the like from entering the inside.

FIG. 4 is a plan view of an exposure apparatus 3 according to the second embodiment of the present invention, and FIG. 5 is a partial side sectional view thereof. The same parts as those in the first embodiment described above are designated by the same reference numerals. The description thereof will be omitted.

In this embodiment, the parts and units attached to the frame 39 in the first embodiment are attached to a flat plate-shaped sub-frame 60 mounted on the main frame 59.

The main frame 59 is screwed and fixed to the main body of the electrophotographic apparatus, and its floor surface is formed as a convex surface having a high central portion and a low peripheral portion. On the other hand, the subframe 60
In the peripheral part, three legs 61 are provided so as to project downward at intervals in the peripheral portion, and the legs 61 are placed on the floor surface of the main frame 59 without being fixed.

Therefore, even if the main frame 59 is slightly tilted or distorted, the sub-frame 60 is not affected by it and receives no force from the side of the main frame 59, and moreover, the foot 61 is always in contact with the main frame 59. Keeps stable without floating from the floor.

Therefore, if the positional relationship between the horizontal synchronization detection sensor 36 and the laser beam is adjusted to a correct state in advance, when the exposure apparatus 3 is attached to the main body 100 of the electrophotographic apparatus, no distortion or the like will occur in the subframe 60. Does not occur and there is no need to readjust.

[0033]

According to the exposure apparatus of the electrophotographic apparatus of the present invention, by providing the working window in the frame, even after the exposure apparatus is attached to the main body of the electrophotographic apparatus, the scanning reference position detecting means and the incident light are incident on it. The position relationship with the laser beam to be adjusted can be finely adjusted by the detection position fine adjustment means, and the exposure apparatus can be electronically mounted by mounting the subframe on which the parts and units are attached without fixing it on the mainframe. Since distortion is not generated on the sub-frame side when it is attached to the main body of the photographic apparatus, the positional relationship between the scanning reference position detecting means and the laser beam does not change.

Therefore, it is possible to perform accurate scanning by detecting the laser beam at the correct detection timing by the scanning reference position detecting means and perform accurate exposure on the photosensitive member.

[Brief description of drawings]

FIG. 1 is a plan view of a first embodiment.

FIG. 2 is a schematic side view of the electrophotographic apparatus of the embodiment.

FIG. 3 is a side partial cross-sectional view of the first embodiment.

FIG. 4 is a plan view of the second embodiment.

FIG. 5 is a side partial cross-sectional view of the second embodiment.

[Explanation of symbols]

1 Photosensitive drum (photoreceptor) 31 Laser diode (laser beam emitting means) 32 polygon mirror (beam scanning means) 36 Horizontal synchronization detection sensor (scan reference position detection means) 38 Working window 39 frames 40 Detection position fine adjustment device (detection position fine adjustment means) 59 Mainframe 60 subframes

Continued front page    (72) Inventor Takeo Kojima             1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture             Within Fujitsu Limited (72) Inventor Takuzo Ikeyama             1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture             Within Fujitsu Limited

Claims (4)

[Claims] 1. A laser beam emitting means (31) for exposing a charged photoreceptor (1), and a laser beam emitted from the laser beam emitting means (31) on the surface of the photoreceptor (1). A beam scanning means (32) for scanning upwards, and in order to detect a reference position of a scanning range by the beam scanning means (32), when the laser beam is incident, it is converted into an electric signal and outputted. The scanning reference position detecting means (36) and the detection position fine adjusting means (40) for finely adjusting the positional relationship between the scanning reference position detecting means (36) and the laser beam incident thereon are common to the frame ( 39. In the exposure device of the electrophotographic apparatus attached to 39), a working window 38 for fine adjustment by the detection position fine adjustment means 40 is provided in the frame 39. An exposure apparatus for an electrophotographic apparatus, which is characterized by: 2. An exposure apparatus for an electrophotographic apparatus according to claim 1, wherein a cover (49) for closing the working window (38) is provided so as to be openable and closable with respect to the working window (38). 3. A laser beam emitting means (31) for exposing a charged photoreceptor (1), and a laser beam emitted from the laser beam emitting means (31) on the surface of the photoreceptor (1). A beam scanning means (32) for scanning upwards, and in order to detect a reference position of a scanning range by the beam scanning means (32), when the laser beam is incident, it is converted into an electric signal and outputted. The main frame (5) fixed to the main body of the electrophotographic apparatus by attaching the scanning reference position detecting means (36) to the common sub-frame (60).
9) An exposure apparatus for an electrophotographic apparatus, characterized in that the subframe (60) is mounted on the subframe without being fixed. 4. The sub-frame (60) is provided with a plurality of legs (61) projecting downward, and the legs (61) are placed on the bottom surface of the main frame (59). The exposure apparatus of the electrophotographic apparatus according to 3.