JP4354587B2 - Exposure apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exposure apparatus for irradiating a photosensitive member with light and an image forming apparatus including the exposure apparatus.
[0002]
[Prior art]
An image forming apparatus adopting an electrophotographic system for an image recording unit used in a printer or the like forms a latent image by irradiating the surface of a charged photoreceptor with a light beam based on image information from an exposure device, and then a developing device Then, the latent image on the surface of the photoreceptor is developed to form a toner image, and then the toner image on the surface of the photoreceptor is transferred to a recording sheet by a transfer device. Usually, an exposure apparatus that exposes a photosensitive member is disposed and supported above the photosensitive member in the main body of the image forming apparatus.
[0003]
On the other hand, recently, as the exposure apparatus for exposing a photosensitive member, which is often used as a laser beam type using a laser beam. Since this laser beam type exposure apparatus requires delicate optical system means such as a laser beam oscillator and a scanner, these optical system means are accommodated inside the case. For this reason, when the laser beam exposure apparatus is provided inside the apparatus main body of the image forming apparatus , a case is attached to the apparatus main body.
[0004]
FIG. 5 schematically shows a configuration in which a laser beam exposure apparatus is provided inside the apparatus main body of a conventional image forming apparatus, FIG. 6 is a perspective view showing the appearance of the exposure apparatus, and FIG. 7 is a plan view. .
In the figure, reference numeral 1 denotes an apparatus main body of the image forming apparatus, 2 denotes a process unit including a photosensitive drum 3 as a photosensitive member, and 4 denotes a laser beam type exposure apparatus disposed above the process unit 2. The exposure apparatus 4 has an optical system means in which a case 5 is combined with devices (not shown) such as a laser beam oscillator, a scanner, a lens and a mirror. The case 5 forms a flat quadrangular box, and a launch port 5a for emitting a laser beam from the optical system means to the outside is formed at a position adjacent to the front edge on the lower surface.
The case 5 is attached to the center position at the front edge portion where the launch port 5a is close and the position near the rear edge portion facing the front edge portion at the two side edges sandwiching the front edge portion, respectively. A member 6 is provided. Each of these attachment members 6 is attached to the apparatus main body 1 by screwing, and has a through hole 6a. That is, the three attachment members 6 are provided at the vertices of the isosceles triangle.
[0005]
In the exposure apparatus arrangement portion of the apparatus main body 1, attachment portions 7 are provided at positions facing the respective attachment members 6 of the case 5, and screw holes 7 a are respectively formed in the attachment portions 7. Each mounting member 6 provided on the case 5 is placed on the mounting portion 7 facing provided on the apparatus main body 1, a bolt into the threaded hole 7a of the through hole 6a and the mounting portion 7 of the attachment member 6 which is combined 8 is screwed. Thereby, the exposure apparatus 4 is restrained and attached to the apparatus main body 1.
[0006]
[Problems to be solved by the invention]
The structure for attaching the exposure apparatus 4 to the apparatus main body 1 of the image forming apparatus in this way has the following problems.
All the attachment members 6 provided at three locations of the case 5 of the exposure apparatus 4 are attached to the attachment portion 7 of the apparatus main body 1 using bolts 8 . In other words, the case 5 of the exposing device 4 is fixed to the apparatus main body 1 and constrained so as not to displace in three places all-. For this reason, when the height of the mounting portion 7 in the apparatus main body 1 is not uniform or there is a displacement between the mounting member 6 of the case 5 and the mounting portion 7 of the apparatus main body 1, the case 5 is It is attached to the apparatus main body 1 in the state in which excessive force is applied.
That is, case 5, in order to attached to to the apparatus body 1 restrained in all the mounting member 6 is attached to the left apparatus main body 1 undertook without missing the mounting condition strain remains.
As described above, when the case 5 of the exposure apparatus 4 is distorted, the laser beam oscillator, the scanner, the lens, the mirror, and the like, which are optical system means accommodated in the case 5, influence the distortion of the case 5. As a result, the optical axis is deviated, the lens is out of focus, or the lens is out of focus. As a result , the accuracy of exposure performed by the exposure device 4 on the photosensitive drum 3 decreases. As a result , there arises a problem that the dots in the image recorded on the recording paper become larger than necessary, and the lines become thicker than necessary, resulting in a decrease in the resolution of the image.
[0007]
Further, there is a problem that the parts used for attaching the exposure apparatus 4 to the apparatus main body 1 and the number of operations for attaching the exposure apparatus 4 are increased.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus that can perform high-precision exposure by reducing distortion when attached to an image forming apparatus, and can be attached with a simple configuration and operation.
[0009]
The present invention performs exposure at a high mounted to distortion of the exposure apparatus does not occur accuracy, and to provide an image forming apparatus capable of recording high-resolution images.
[0010]
[Means for Solving the Problems]
In order to achieve the object, an exposure apparatus according to the invention of claim 1 comprises:
Provided in the apparatus body of the image forming apparatus, an exposure apparatus for irradiating a light beam based on image information on the photosensitive member, and optical means for emitting the light beam toward the photosensitive member, accommodating the optical system unit are provided and the case, the.
Wherein the case includes a mounting member in three places corresponding to the respective vertexes of a triangle in its periphery, the one of the mounting members of these three attachment members, the optical axis of the light beam the optical means emits A conical portion having a downward apex, and the conical portion is combined with a receiving concave portion having a larger conical shape than the conical portion provided in the apparatus main body, and the receiving concave portion is the conical portion The one mounting member is supported in a state in which it can move freely with respect to the apparatus main body with the vertex of the conical part serving as a fulcrum,
The two attachment members having the same distance from the one attachment member are attached to the apparatus main body in a state in which movement is restricted by using a fixing member .
[0011]
According to the configuration of the present invention, it is possible to attach the case to the apparatus main body of the image forming apparatus without undue stress by escaping the distortion generated in the case. Thereby, it is possible to effectively avoid the optical axis of the light beam having the highest degree of influence due to the distortion generated in the case from the influence of the distortion generated in the case.
[0016]
According to a second aspect of the present invention, in the exposure apparatus according to the first aspect, the optical system means emits a laser beam.
[0017]
According to a third aspect of the present invention, there is provided an image forming apparatus according to the first or second aspect of the present invention, and a process unit having a photoconductor exposed by a light beam emitted from the optical system means of the exposure apparatus, It is characterized by comprising .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
This embodiment is applied to a printer apparatus equipped with a laser beam type exposure apparatus. 1 is a diagram schematically showing the configuration of a printer apparatus equipped with a laser beam type exposure apparatus, FIG. 2 is a perspective view showing the appearance of the laser beam type exposure apparatus, FIG. 3 is a plan view, and FIG. 4 is a laser beam type. It is a figure which expands and shows the part which supports an exposure apparatus to an image type apparatus main body in a free state.
[0019]
In FIG. 1, reference numeral 11 denotes an apparatus main body of the image forming apparatus, and each mechanism described below is provided inside the apparatus main body 11. Reference numeral 12 denotes a process unit, which is a photosensitive drum 13 that is a photosensitive member, a charging device (not shown), a cleaning device, a case 14 that supports them, and a developing device 15 that are integrated together. The surface of the photosensitive drum 13 is charged, exposed by an exposure device 31 described later, and a toner image is formed on the surface of the photosensitive drum 13 by the developing device 15. Reference numeral 16 denotes a transfer device that transfers the toner image on the photosensitive drum 13 onto the recording paper, 17 denotes a fixing device that fixes the toner image transferred onto the recording paper, and 18 denotes a conveyance roller that conveys the recording paper. Reference numeral 19 denotes a recording paper cassette that is mounted on the apparatus main body 11 and stores recording sheets for recording images, and 20 is a paper discharge tray that discharges the recording paper that has been formed on the apparatus main body 11 and has finished image recording.
[0020]
Reference numeral 31 denotes a laser beam exposure apparatus disposed on the upper side of the process unit 12. The exposure apparatus 31 is one in which an optical system means 33 is housed in a case 32. The case 32 forms a rectangular flat box made of metal or synthetic resin, and a launch port 32a is formed at a location close to the front edge on the lower surface. The optical system means 33 is a combination of devices such as a laser beam oscillator 41, a scanner 42, a lens 43, and a mirror 44, and the scanner 42 scans the laser beam oscillated by the laser beam oscillator 41 based on the image information. Light is irradiated onto the surface of the photosensitive drum 13 of the process unit 12 provided below the exposure device 31 from a launch port 32a formed on the lower surface of the case 32 via a lens 43 and a mirror 44. The optical axis of the laser beam emitted from the optical system means 33 is a line A connecting the center point in the width direction of the front edge portion 32b and the center point in the width direction of the rear edge portion 32d as shown in FIG. is there.
[0021]
Further, the case 32 is provided with a mounting member 34 at a central position in the rear edge portion 32d, and a front edge portion 32b facing the rear edge portion 32d in the two side edge portions 32c sandwiching the rear edge portion 32d. each mounting member 35 is provided in the approximated position. These three mounting members 34 and 35 are isosceles triangles (regular triangles) in which the length of the side connecting the mounting member 34 and one mounting member 35 is equal to the length of the side connecting the mounting member 34 and the other mounting member 35. Is located at each vertex.
When the case 32 is made of metal, the mounting members 34 and 35 are made of metal and fixed to the case 32 by screwing or welding, and when the case 32 is made of synthetic resin, It is formed integrally or fixed to the case 32 by screwing.
A single attachment member 34 formed at the center of the rear edge portion 32d of the case 32 has a flat portion projecting outward from the case 32 so as to be flush with the lower surface portion of the case, and a lower portion from the flat portion. those having a conical portion 34a projecting at right angles towards the side. The conical portion 34a is formed with its orientation set so that its apex is downward. The apex of the conical portion 34a is positioned below the optical axis A of the laser beam emitted from the optical means 33 described above.
Further, the two attachment members 35 provided on the left and right side edges 32c of the case 32 are formed on the flat surface portion that protrudes outward from the case 32 so as to be flush with the lower surface portion of the case. And a through hole 35a.
[0022]
Further, the exposure apparatus arrangement portion in the apparatus main body 1 is provided with a mounting portion 36 at a position facing one mounting member 34 of the case 32, and a mounting portion 37 at a position facing each of the two mounting members 35. Is provided. Each of the mounting members 36 and 37 is formed of , for example, metal and is integrally formed with the apparatus main body 11, or is fixed by screwing or welding, and is formed of, for example, synthetic resin and is integrally formed with the apparatus main body 11, or is screwed. It is more fixed on.
As shown in FIG. 4, a single mounting section 36 receives the recess 36a receiving and supporting the apex of the conical portion 34a of the mounting member 34 is formed, the two are the mounting portion 37 respectively threaded holes 37a Is formed. The receiving recess 36a has a conical shape slightly larger than the top of the conical portion 34a so that the conical portion 34a can be inclined by a certain angle and can be rotated by a certain angle around the axis.
Then, the exposure device 31 is disposed on the upper side of the mounting portions 36 and 37, one attachment member 34 provided on the case 32, a conical portion opposite the upper mounting portion 36 provided on the apparatus main body 11 The apex of 34a is combined with the receiving recess 36a . In this case, the apex of the conical portion 34a of the mounting member 34, the slope only certain angle in the recess 36a receiving the mounting portion 36, is and supported in a free state so that it can rotate only certain angle around the axis.
Each mounting member 35 provided on the case 32, the device is placed to overlap the upper surface of each mounting member 37 facing provided on the main body 11, the screw hole 37a of the through hole 35a and the mounting portion 37 of the mounting member 35 are combined A bolt 38, which is one form of the fixing member, is screwed and tightened. Thus, the mounting portion 37 and the attachment member 35 are combined is attached to the apparatus main body 11 is restrained so as not to move. The fixing member, and the like welding material in the case of performing the welding other.
[0023]
As a result, the case 32 of the exposure apparatus 31 is restrained and fixed by the two attachment members 35 so as not to move to the apparatus main body 11, and is freely supported by the apparatus main body 11 by the one attachment member 34. It is stably supported at three locations corresponding to the vertices of the isosceles triangle.
For example, the case 32 is bent, the vertical positions of the mounting portions 36 and 37 of the apparatus main body 11 are uneven, or between the mounting members 34 and 35 of the case 32 and the mounting portions 36 and 37 of the apparatus main body 11. If the attachment members 35 provided on the case 32 are fixedly attached to the attachment portions 37 provided on the apparatus main body 11 with screws, the case 32 is bent in response to this attachment state. In other words, the case 32 is forcibly attached to the apparatus body 11 by applying an excessive force to the case 32.
Here, the attachment member 34 provided in the case 32 is supported in a free state so that it can be inclined at a certain angle with respect to the attachment portion 36 provided at the apparatus main body 11 and can be rotated by a certain angle around the axis. Therefore, the case 32 can move with the mounting member 34 as a fulcrum. For this reason, according to the unreasonable state which arose in case 32 by fixation of each attachment member 35 and each attachment part 37, case 32 has an unreasonable state by using the attachment member 34 supported on the attachment part 36 as a fulcrum. Move to return to.
In other words, the unreasonable state generated in the case 32 is corrected by using the free mounting member 34 as a fulcrum and making the case 32 unreasonable. Specifically, the strain caused by excessive state on the case 32 reduces the presence of the strain missed the outside of the case 32 by the case 32 moves free mounting member 34 as a fulcrum substantially. That is, residual strain in the case 32 can be eliminated.
[0024]
Thus, in the case where there is misalignment between the mounting members 34 and 35 of the case 32 and the attaching portions 36 and 37 of the apparatus main body 11, it is attached to the case 32 in the apparatus main body 11, the casing 32 the device body 11 can be attached in a state where it is not unreasonable. Therefore, the laser beam oscillator 41 is an optical system unit 33 to be housed inside the case 32, scanner 42, such as a lens 43 and a mirror 44 is displaced under the influence of distortion of the case 32, the optical axis deviation Or the out of focus of the lens can be prevented.
As a result, the exposure device 31 can expose the photosensitive drum 13 with high accuracy, and records dots and lines in the image recorded on the recording paper with an appropriate size to ensure the resolution of the image. it can.
[0025]
Further, since two of the three attachment members 34 and 35 of the case 32 are screwed, the exposure apparatus 31 is configured in comparison with a configuration in which all of the three attachment members 34 and 35 are screwed. There are few parts used for attachment to the apparatus main body 11, and the number of work for attachment is also simple.
[0026]
One mounting member 34 supported in a free state among the three mounting members 34 and 35 provided in the case 32 is a light beam of a laser beam emitted by the optical system means 33 as shown in FIG. Located on axis A. For this reason, it is possible to effectively avoid the optical axis A of the laser beam having the highest degree of influence due to the distortion generated in the case 32 from the influence of the distortion generated in the case 32.
[0027]
Furthermore, case one attachment member 34 which is supported in a free state of the three mounting members 34, 35 provided in 32 has a conical portion 34a which apex is formed so as to face the lower side The conical portion 34a is placed and supported on a mounting portion 36 provided in the apparatus main body 11 . Thus, the mounting member 34 is moved freely and smoothly, the attachment member 34 which is supported in a free state in the case 32 can be most effectively exert their effects.
[0028]
Since the exposure apparatus 31 using a laser beam can be exposed with high accuracy, it needs to be attached to the apparatus main body 11 with high accuracy. be able to.
[0029]
In this embodiment, a printer apparatus is targeted as one form of the image forming apparatus. However, in this printer apparatus, the exposure apparatus 31 is not distorted and can be exposed with high accuracy to record a high resolution image. it can.
[0030]
In addition, according to this invention, it is not limited to embodiment mentioned above, It can implement in various deformation | transformation.
[0031]
【The invention's effect】
According to the exposure apparatus of the present invention, it is possible to attach the case to the apparatus main body of the image forming apparatus without difficulty by escaping the distortion generated in the case. Therefore, the case of attaching the exposure apparatus to the image forming apparatus can reduce the distortion of the case to perform high-precision exposure and perform high-resolution image recording. Can be installed on.
[0034]
According to the image forming apparatus according to the present invention, exposure with high attached to strain an exposure apparatus does not occur precision, it is possible to record a high resolution image.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of an image forming apparatus equipped with an exposure apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view showing an exposure apparatus according to the same embodiment.
FIG. 3 is a plan view showing an exposure apparatus according to the same embodiment.
FIG. 4 is an enlarged view showing a configuration for supporting an exposure apparatus in the embodiment.
FIG. 5 is a diagram schematically showing a configuration of an image forming apparatus equipped with a conventional exposure apparatus.
FIG. 6 is a perspective view showing the conventional exposure apparatus.
FIG. 7 is a plan view showing the conventional exposure apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Apparatus main body, 12 ... Process unit, 13 ... Photoconductor (photosensitive drum), 31 ... Exposure apparatus, 32 ... Case, 33 ... Optical system means, 34, 35 ... Mounting member, 34a ... Conical part, 36, 37 ... Attaching part, 36a ... Receiving recess, 38 ... Fixing member (bolt).

Claims (3)

An exposure apparatus that is provided in a main body of an image forming apparatus and irradiates a photoconductor with a light beam based on image information ,
And optical means for emitting the light beam toward the photosensitive member,
Anda case for housing said optical means,
Wherein the case includes a mounting member in three places corresponding to the respective vertexes of a triangle in its periphery, the one of the mounting members of these three attachment members, the optical axis of the light beam the optical means emits A conical portion having an apex facing downward; the conical portion is combined with a receiving concave portion having a larger conical shape than the conical portion provided in the apparatus main body, and the receiving concave portion is the conical portion The one mounting member is supported in a state in which it can move freely with respect to the apparatus main body with the vertex of the conical part serving as a fulcrum,
An exposure apparatus characterized in that two attachment members having the same distance from the one attachment member are attached to the apparatus main body in a state in which movement is restricted using a fixing member . 2. The exposure apparatus according to claim 1, wherein the optical system means emits a laser beam . An image forming apparatus comprising: the exposure apparatus according to claim 1 or 2; and a process unit having a photoconductor exposed by a light beam emitted from an optical system unit of the exposure apparatus. apparatus.

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