JP3458639B2 - Optical scanning device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device used in an image forming apparatus using an electrophotographic process technology such as a laser printer, a facsimile, a copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic process technique, an electrostatic latent image is formed on a uniformly charged photosensitive member by scanning light from an optical scanning device, and the electrostatic latent image is formed. The image is developed with toner, and the obtained toner image on the photoconductor is transferred and fixed on a sheet to record the image. This optical scanning device is usually fixed to the frame of the image forming apparatus by screwing or the like.

In such an image forming apparatus, the temperature of the entire inside of the apparatus rises due to the heat generated from the motor, electric circuit and sliding parts inside the apparatus during operation.

At this time, if the optical scanning device and the frame of the main body of the image forming apparatus are made of different materials, a difference occurs in the amount of expansion due to the heat of the two, and the optical scanning device is bent or deformed, so that the optical scanning device is exposed. The optical axis of the laser light emitted toward the body may be distorted, and the image quality may be degraded.

To solve this problem, Japanese Patent Laid-Open No. 6-123849 has been proposed as a technique.

This is because when the optical scanning device is attached to a plane parallel to the scanning surface of the laser beam, the movement of the optical scanning device is allowed in the direction parallel to this surface and is blocked in the direction perpendicular to the surface. It is configured to release the distortion due to the thermal expansion of the optical pedestal. This prevents the optical axis of the laser beam from being distorted even if the temperature rises.

In the embodiment, the structure is such that the optical housing is pressed against the flat surface by the springs through the balls at the three fixed parts, so that the three fixed parts are allowed to move in the direction parallel to the scanning plane. It is said to be blocked in the vertical direction. In addition to the ball, an example using a slider such as a washer has been proposed.

[0008]

Generally, in an optical scanning device, the vibration of a motor for rotating a rotary polygon mirror mounted on the optical scanning device is transmitted to an optical component and the laser beam to be scanned vibrates. There is. As a result, a phenomenon known as banding is known in which the writing position of the laser beam on the photoconductor changes in the sub-scanning direction and the spacing between the scanning lines shifts, causing striped density unevenness.

In order to prevent such image distortion, when mounting the optical scanning device on the frame of the image forming apparatus main body, it is important to ensure that all the fulcrums of the optical scanning device are in contact with and supported by the frame. .

In the technique of the above-mentioned Japanese Patent Laid-Open No. 6-123849, when there are three support portions as in the embodiment, the plane is established at three locations, so there is no floating point, but there are four support portions. In the case of more than one place, it is difficult to manufacture the flatness between the supporting portions to 0 in manufacturing, and a slight difference in height usually occurs between the supporting portions. In particular, when glass reinforced fiber plastic is used as the material of the optical pedestal, a slight dimensional error occurs in the entire optical pedestal due to "sinking" or "sledding" that occurs during molding.

If there is an error in the flatness between the support portions in this way, there is a support portion that cannot be pressed against the fixed plane only by the pressing force of the spring, and the floating support portion may be fixed as it is. As a result, the optical scanning device itself tends to vibrate, and the vibration of the motor for rotating the rotary polygon mirror tends to cause the above-mentioned image disturbance.

In consideration of the above facts, it is a first object of the present invention to provide an optical scanning apparatus which has achieved the above-mentioned objects of the prior art and has eliminated and improved the above-mentioned drawbacks.
Even when the flatness of the optical scanning device support portion is deviated by a predetermined amount, all the points of the support portion can be pressed against the mounting plane so that the optical scanner can be mounted so as to be less susceptible to vibration.
Is the purpose of.

[0013]

According to a first aspect of the invention, a light beam emitted from the light source is mounted on an attachment surface of an image forming apparatus, and a plurality of optical components including a light source are mounted on an optical pedestal. An optical scanning device for scanning a plurality of supporting portions provided on the optical pedestal for performing vertical positioning with respect to the mounting surface, and one supporting portion provided on the optical pedestal and fixed to the mounting surface. A fixing portion, the optical pedestal is formed of an elastically deformable material, and has a gap between the fixing portion and the mounting surface before the fixing portion is fixed to the mounting surface. When the parts are fixed to the mounting surface, at least a part of the optical pedestal is elastically deformed to eliminate the gap, and the plurality of supporting parts are all in contact with the mounting surface.

Next, the operation of the optical scanning device according to the first aspect will be described. In the optical scanning device according to claim 1, when the fixing portion is fixed to the mounting surface of the image forming apparatus with a screw or the like, a part of the optical pedestal is elastically deformed and the plurality of supporting portions are all in contact with the mounting surface and fixed. To be done. Since the support portion performs vertical positioning with respect to the mounting surface, when the optical pedestal is fixed, vertical positioning of the optical component with respect to the mounting surface is performed.

Further, since there is no supporting portion floating from the mounting surface, the optical scanning device is hard to vibrate. Furthermore, the optical base thermally expands due to the temperature rise, but since the optical base is fixed to the mounting surface by one fixing part, the optical base thermally expands around this fixing part in the circumference (radial direction) and is mounted. The supporting portion that is in contact with the surface and is not fixed can move along the mounting surface, and the optical alignment of the optical component does not change due to temperature change.

According to a second aspect of the present invention, in the optical scanning device according to the first aspect, there are at least three supporting portions, and the fixing portion is substantially in the center of a polygon formed by the supporting portions. It is characterized by being located.

Next, the operation of the optical scanning device according to the second aspect will be described. In the optical scanning device according to claim 2, since there are at least three supporting portions and the fixed portion is located at a substantially central portion of the polygon formed by the supporting portions, each supporting portion can be reliably and evenly formed. Can be brought into contact with the mounting surface.

According to a third aspect of the present invention, in the optical scanning device according to the first or the second aspect, a high rigidity region whose rigidity is increased by the ribs and a low rigidity region whose rigidity is not increased by the ribs are provided. Are provided on the optical pedestal, and the optical component is supported in the high rigidity region.

Next, the operation of the optical scanning device according to the third aspect will be described. In the optical scanning device according to claim 3, a high rigidity region whose rigidity is increased by the ribs and a low rigidity region whose rigidity is not increased by the ribs are provided on the optical pedestal, and the optical component is supported in the high rigidity region. Therefore, when fixed, the low-rigidity region elastically deforms, and the optical alignment of the optical components does not change. Further, since the high rigidity region is hard to be deformed, it is hard to vibrate, and the fluctuation of the optical alignment due to the vibration can be suppressed.

According to a fourth aspect of the present invention, in the optical scanning device according to the third aspect, one of the fixed portions and a support point for supporting the Fθ lens in the optical component are provided in the high rigidity region. It is characterized by that.

Next, the operation of the optical scanning device according to the fourth aspect will be described. In the optical scanning device according to claim 4, since the fixed portion and the support point for supporting the Fθ lens in the optical component are provided in the high rigidity region, the Fθ lens includes the support point, the high rigidity region, and the fixed portion. Firmly connected to the mounting surface,
Vibration of the Fθ lens can be reliably suppressed.

According to a fifth aspect of the present invention, in the optical scanning device according to any one of the first to fourth aspects, one of the supporting portions is located near the light source. I am trying.

Next, the operation of the optical scanning device according to the fifth aspect will be described. In the optical scanning device according to the fifth aspect, since one of the supporting portions is located near the light source, vibration of the light source can be suppressed.

The invention according to claim 6 is the same as claim 1.
The optical scanning device according to claim 5, wherein the optical pedestal is made of a material having substantially the same coefficient of linear expansion as the mounting portion of the image forming device, between the optical pedestal and the image forming device. It is characterized in that it is mounted and fixed through a bracket having various rigidity.

Next, the operation of the optical scanning device according to the sixth aspect will be described. If the rigidity of the mounting portion of the image forming device to which the optical scanning device is attached is low, the mounting portion of the image forming device may be deformed when the optical scanning device is attached, and the supporting portion of the optical scanning device may not contact the image forming device. To be
However, if the optical pedestal is mounted and fixed to the image forming apparatus via a bracket having a material having substantially the same linear expansion coefficient as that of the mounting portion of the image forming apparatus and having sufficient rigidity, the supporting portion of the optical scanning apparatus can be secured. All can be brought into contact with the bracket, and the optical scanning device can be made difficult to vibrate. Furthermore, the optical pedestal thermally expands due to the temperature rise, but since the optical pedestal is fixed to the bracket by one fixing part, the optical pedestal thermally expands in the periphery (radial direction) around this fixing part, and the mounting surface The support part that is not fixed by contacting with the can move along the mounting surface, and the optical alignment of the optical component does not change due to the temperature change. Further, although the bracket is fixed to the image forming apparatus, since the bracket is formed of a material having substantially the same linear expansion coefficient as the mounting portion of the image forming apparatus, the bracket is not deformed due to the difference in linear expansion coefficient.

[0026]

DETAILED DESCRIPTION OF THE INVENTION

[First Embodiment] A first embodiment of the optical scanning device of the present invention will be described with reference to FIGS.

FIG. 1 is a plan view of the optical scanning device 10, and FIG. 4 is a bottom view of the optical scanning device 10. FIG. 5 is a plan view of the frame 14 of the image forming apparatus main body in which the optical scanning device 10 is mounted.

As shown in FIG. 1, the optical scanning device 10 includes an optical pedestal 12 having a substantially square shape. This optical pedestal 12
Has an outer rib 48 on the outer peripheral portion and a plurality of ribs 50 on the lower surface, and is integrally formed of, for example, a synthetic resin reinforced with glass fiber or the like.

A light source 16 for emitting a laser beam, a collimator lens 18, and a cylinder lens 2 are mounted on the optical pedestal 12.
0, the rotary polygon mirror 22 rotated by the motor 21, the first Fθ
Lens 24, second Fθ lens 26, cylinder lens 2
7, a mirror 28 and a light receiving element 29 are attached.

The motor 21 is the boss 2 of the optical base 12.
It is attached to 3A, 23B, and 23C. The first Fθ lens 24 has a convex support point 25 formed on the upper surface of a rectangular boss 25 provided at the center of the optical pedestal 12.
Three points are supported on A, 25B and 25C, and the second Fθ lens 26 is supported on three support points 25D, 25E and 25F.

The laser light 30 emitted from the light source 16 is
It passes through the collimator lens 18 and the cylinder lens 20, and is deflected by the rotary polygon mirror 22. The deflected and scanned laser light 30 passes through an image forming optical system including a first Fθ lens 24, a second Fθ lens 26, and a cylinder lens 27, and is imaged / scanned on the photosensitive member surface 32.

The light receiving element 29 detects the laser beam 30 on the scanning start side and generates a signal for determining the scanning start timing.

As shown in FIG. 4, on the lower surface of the optical pedestal 12, four support portions 34, 36, 38, 40 for positioning the optical scanning device 10 in the height direction are formed at the corners. , One fixing part 4 integrated with the boss 25 in the central part
2 is formed, and a positioning pin 44 is formed at a position apart from the fixed portion 42.

As shown in FIGS. 2 and 4, the fixing portion 42 has a bottomed cylindrical shape, and a hole 46 is formed at the center of the bottom portion.

In the optical pedestal 12 of this embodiment, a quadrilateral region 51 (a trapezoidal portion surrounded by points 51A, 51B, 51C and 51D) formed by the ribs 50 or the ribs 50 and the outer ribs 48 is formed. 53 (points 53A, 53B, 53
The trapezoidal portion surrounded by C and 53D), the triangular region 55 (the triangular portion surrounded by points 55A, 55B and 55C) and the triangular region 57 (the triangular portion surrounded by points 57A, 57B and 57C) are ribs 50 or ribs. A high-rigidity region reinforced by 50 and the outer rib 48, and an elongated groove-shaped region 59 sandwiched between the quadrilateral region and the triangular region is a low-rigidity region.

As shown in FIGS. 2 and 5, the upper surface (mounting plane 14A) of the frame 14 on which the optical scanning device 10 is mounted.
Is a plate member 54 having a round hole 52 into which the fixing portion 42 is fitted.
Are fixed by spot welding or the like. A screw hole 56 is formed in the frame 14 at the center of the round hole 52, and an elongated hole 58 into which the positioning pin 44 is inserted is formed at a position away from the screw hole 56. .

In this optical scanning device 10, the fixing portion 42 is fitted in the round hole 52 of the plate member 54, and the positioning pin 44 is in the long hole 5.
The position in the mounting plane direction is determined by being inserted into 8.

Here, as shown in FIG.
The optical pedestal 123, which is only mounted on, has a slightly raised central portion, and a predetermined amount of gap 60 is provided between the fixed portion 42 and the mounting plane 14A.

As shown in FIGS. 3 and 6, the fixing screw 62 is passed through the hole 46 provided in the fixing portion 42, and the fixing screw 62 is tightened in the screw hole 56 provided in the mounting plane 14A.
The fixing portion 42 is attached to the mounting plane 1 by the fastening force of the fixing screw 62.
It is pushed down and fixed until it contacts 4A.
At this time, in the optical pedestal 12, the elongated groove-shaped region 59, which is a low-rigidity region, is mainly deformed, and the support portions 34, 36,
The whole 38, 40 comes into contact with the mounting plane 14A.

In this state, the optical scanning device 10 of the present embodiment includes the light source 16, the collimator lens 18, the cylinder lens 20, the rotary polygon mirror 22 rotated by the motor 21, and the first mirror.
A holding datum (reference surface) of each optical component is formed on the optical pedestal 12 so that positional accuracy of each optical component such as the Fθ lens 24, the second Fθ lens 26, the cylinder lens 27, the mirror 28, and the light receiving element 29 is established. ing. The optical adjustment of the optical scanning device 10 is performed in a similar mounting state on a jig having a mounting plane equal to the mounting plane 14A of the image forming apparatus body.

In the optical scanning device 10 of this embodiment, when it is fixed to the mounting plane 14A of the main body of the image forming apparatus, since there is no floating supporting portion, it is vibrated by the vibration source such as the motor 21 for rotating the rotary polygon mirror 22. Hard to be affected by.

Further, even if the temperature rises in this state, 4
The supporting portions 34, 36, 38, 40 at the points are pressed against the mounting plane 14A by the urging force generated by the bending of the optical pedestal 12. At the same time, the optical pedestal 12 is fixed to the fixed portion 42
Although it thermally expands to the periphery (radial direction) centering on, the four support portions 34, 36, 38, 40 are not fixed, so that they can move along the mounting plane 14A,
The optical alignment of the optical components does not change.

Incidentally, as shown in FIG.
By arranging the support portions 34, 36, 38, 40 at the locations at substantially the center of the quadrangle, the biasing force due to the bending of the optical pedestal 12 causes the support portions 34, 36, 38, 40 at the four locations.
Since they are distributed almost evenly, the action of bringing all the support portions 34, 36, 38, 40 into contact with the mounting plane 14A is facilitated. [Second Embodiment] A second embodiment of the present invention will be described with reference to FIGS. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The optical pedestal 64 of the second embodiment differs from the optical pedestal 12 of the first embodiment in the position of the rib 50,
This is an example in which the optical pedestal 64 is provided with a high rigidity region and a low rigidity region, and the optical component is held in the high rigidity region.

As shown in FIG. 8, the frame 14 of this embodiment is formed with a round hole 66 into which the fixing portion 42 is fitted. The round hole 66 is formed on the lower surface side of the frame 14 (the mounting plane 14A and the mounting plane 14A). On the opposite side) is closed by a plate material 68 that is spot-welded or the like. A screw hole 70 is provided at the center of the plate 68.
Are formed.

As shown in FIG. 10, the optical pedestal 64 of this embodiment has a quadrilateral region 66 (point 66A, point 66A, which is formed by the ribs 50 (ribs 50A) or between the ribs 50 and the outer ribs 48.
66B, 66C, 66D), a quadrilateral area 68 (trapezoid surrounded by points 68A, 68B, 68C, 68D), a quadrilateral area 70 (points 70A, 70B, 7)
Trapezoidal part surrounded by 0C and 70D), quadrilateral region 72
(A trapezoidal portion surrounded by points 72A, 72B, 72C, 72D) and a quadrilateral region 74 (points 74A, 74B, 74C,
The square portion surrounded by 74D is a rib 50 (rib 50).
A) It is a high-rigidity region reinforced by the ribs 50 and the outer ribs 48 or by the ribs 50, and the elongated groove-shaped region 76 sandwiched between the quadrilateral regions is a low-rigidity region.

Here, as shown in FIGS. 7 to 10, the supporting points 25A, 25B, 25C of the first Fθ lens 24 and the supporting points 25D, 25E, 25F of the second Fθ lens 26 are supported.
Is inside the quadrilateral region 74, which is a high rigidity region reinforced by the ribs 50. In addition, the motor 21 of the rotary polygon mirror 22
The bosses 23A, 23B, and 23C for holding are located inside the quadrilateral region 66, which is a high-rigidity region.
9 is also inside this quadrilateral region 66.

The ribs 50 forming the quadrilateral region 74
A is integrated with the fixing portion 42.

Also in this embodiment, as shown in FIG. 8, the optical scanning device 1 is only mounted on the frame 14.
0 is between the rib 50A and the mounting plane 14A and the fixing portion 4
There is a predetermined amount of gap 60 between the plate 2 and the plate member 68.

In the process of mounting the optical scanning device 10 on the mounting plane 14A of the image forming apparatus, the holes 4 of the fixing portion 42 are formed.
When the fixing portion 42 is pushed down while rotating the fixing screw 62 passed through 6, the whole lower end of the rib 50A of the quadrilateral region 74, which is a high rigidity region, comes into contact with the mounting plane 14A and the fixing is completed. At this time, in the optical pedestal 64, the elongated groove-shaped region 76, which is a low-rigidity region, is mainly deformed, and the support portions 34, 36, 38, 40 at the four locations are deformed as in the first embodiment.
The whole contacts the mounting plane 14A.

In this state, the first Fθ lens 24 and the second F lens
The positional accuracy of the θ lens 26 in the height direction (direction of arrow H in FIG. 9) is defined by the height of the rib 50A. However, the quadrilateral region 74, which is a high rigidity region, is the entire optical scanning device 10. Since it is a narrow region, the height of the rib 50A can be accurately built.

Generally, in an optical scanning device, the tilting of the Fθ lens may cause the scanning plane after the Fθ lens to be curved or tilted to deteriorate the image quality, but in the present embodiment, the first Fθ lens 24 and Second Fθ lens 2
6 support points 25A, 25B, 25C, 25D, 25E,
Since the Fθ lens supporting surface is established when the rib 50A arranged directly below the range including the 25F (quadrilateral region 74) comes into contact with the mounting plane 14A, when the optical pedestal 64 is thermally expanded, the first Fθ lens 24 and the first Fθ lens 24. The 2Fθ lens 26 is prevented from tilting, and the scan plane is not curved or tilted.

Further, since the optical parts such as the rotary polygon mirror 22 and the light receiving element 29 are held in the high rigidity region, the bosses 23A, 23B, 23C and the light receiving element 29 to be held are not distorted. Since the positional relationship between the held points does not change, the positional accuracy of the optical component is maintained. further,
Since the optical component is held in the high-rigidity region, it is possible to make it difficult to vibrate. [Third Embodiment] A third embodiment of the present invention will be described with reference to FIGS. The same components as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 12, the optical pedestal 77 of the present embodiment is provided with a fixing portion 42 at substantially the center thereof, and six supporting portions 78, 80, 82, 84, 86, 88 near the outer periphery.
Is provided.

The triangular regions 90, the triangular regions 92, the triangular regions 94, the triangular regions 96, the triangular regions 98 and the triangular regions 100 formed by the ribs 50 or the ribs 50 and the outer ribs 48 are the ribs 50 or the ribs 50. Outer rib 48
It is a high-rigidity region reinforced with and the elongated groove-shaped region 102 sandwiched between the triangular regions is a low-rigidity region.

These triangular regions 92 to 100 are characterized in that they are supported at a total of three positions of the fixed part 42 and the two support parts of the support parts 78, 80, 82, 84, 86 and 88. With such a configuration, when the optical scanning device 10 is mounted on the mounting plane 14A of the image forming apparatus, all the supporting portions 78, 80,
The action of bringing 82, 84, 86 and 88 into contact with each other is facilitated. This will be described by taking one triangular region 90, which is a high rigidity region, shown in FIG. 12 as an example.

The optical scanning device 10 is fixed to the fixing portion 4 while rotating the fixing screw 62 in the same manner as the above-described embodiment.
When 2 is pushed down, one of the supporting portion 78 and the supporting portion 80, which has a larger finished protrusion amount, comes first to the mounting plane 14A.
To contact. If the amount of protrusion of the support portion 78 is large, the support portion 78 first and then the support portion 80 contact the mounting plane 14A. From this time point, the triangular area 92, which is a high-rigidity area, rotates in the direction in which the point O moves downward with the straight line m connecting the support portion 78 and the support portion 80 as the rotation center. Further, when the fixing screw 62 is further rotated to lower the fixing portion 42, the fixing is finished when the fixing portion 42 comes into contact with the mounting plane 14A and cannot be further pushed down.

That is, one high rigidity region (triangular region)
Is first supported at two supporting portions near the outer periphery of the optical pedestal 77, and is rotated about a straight line connecting the two supporting portions until the fixing portion 42 contacts the mounting plane 14A. Since this operation is simultaneously performed in each of the high rigidity regions, all the supporting portions 78,
The action of bringing the 80, 82, 84, 86, 88 into contact with each other is facilitated. [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIG. The same components as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The optical pedestal 104 of this embodiment is a modification of the optical pedestal 64 of the second embodiment described above, and the light source 1
This is an example in which the support portion 106 is provided substantially directly below the light source 6, so that the light source 16 is prevented from becoming an antinode of the vibration of the optical pedestal 64. Therefore, the angle change due to the vibration of the laser beam 30 emitted from the light source 16 is suppressed, and the optical scanning device 10 in which banding is unlikely to occur can be obtained. [Fifth Embodiment] A fifth embodiment of the present invention will be described with reference to FIGS. The same components as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the optical scanning device 10 of the first embodiment is fixed to the image forming apparatus via a bracket 108 having sufficient rigidity with substantially the same linear expansion coefficient as the frame 14 of the image forming apparatus. This is an example.

In this embodiment, assuming that the frame 14 of the image forming apparatus is made of iron, the bracket 108 is made of iron sheet metal.

As shown in FIGS. 14 to 16, a mounting plane 108A is formed on the upper surface of the bracket 108, and a plate member 54 having a round hole 52 into which the fixing portion 42 fits is spot-welded on the mounting plane 108A. It has been fixed and fixed.
A screw hole 56 is formed in the bracket 108 at the center of the round hole 52, and a long hole 58 into which the positioning pin 44 is inserted is formed at a position away from the screw hole 56.

Leg portions 110 and 112 having an L-shaped cross section are formed on the outer peripheral portion of the bracket 108.
An elongated hole 118 and a round hole 120 that fit into two positioning pins 114 and 116 provided on the frame 14 of the image forming apparatus are formed in the center of the frames 0 and 112, and the frame 14 is formed near both ends. A hole 122 through which a fixing screw to be screwed is inserted is formed.

Further, the bracket 108 has a high rigidity by being subjected to a drawing process 124 for reinforcing the whole.

In the present embodiment, the optical scanning device 10
Is first attached and fixed to the bracket 108. Fixed part 42 and positioning pin 44 of optical scanning device 10
Are fitted into the round holes 52 and the long holes 58 provided on the mounting plane 108A of the bracket 108, respectively,
The position in the mounting plane direction with respect to the bracket 108 is determined.

When the fixing screw 62 is tightened in the screw hole 56, the fixing portion 62 is tightened by the fastening force of the fixing screw 62.
Is pressed down and fixed until it contacts the mounting plane 108A. At this time, the optical pedestal 12 is bent by a predetermined amount, and the entire four support portions 34, 36, 38, 40 come into contact with the mounting plane 108A.

The assembly 126 of the optical scanning device 10 and the bracket 108 integrated in this way is attached to the frame 14 of the image forming apparatus having substantially the same coefficient of linear expansion as the bracket 108. The mounting is performed by fitting the long holes 118 and the round holes 120 of the bracket 108 to the two positioning pins 114 and 116 provided on the frame 14 of the image forming apparatus, and then positioning the four holes 122. The fixing screws 128 are fixed to the frame 14 with screws.

Also in the present embodiment, the flatness error between the support points of the optical pedestal 12 and the thermal expansion of the optical pedestal 12 have sufficient rigidity with the optical scanning device 10 by the same operation as in the above-described embodiments. It is absorbed between the bracket 108. Further, the bracket 108 is attached to the periphery of the image forming apparatus.
Although fixed in place, the frame 14 of the image forming apparatus
Since it is the same material as, the deformation due to the difference in linear expansion coefficient does not occur.

Normally, the frame of an image forming apparatus is equipped with various subsystems such as a developing device and a fixing device as well as an optical scanning device, and a shape for holding each device must be formed. Instead, it is designed under many constraints. Therefore, when the optical scanning device 10 of the present embodiment is fixed, it may not be possible to provide the rigidity that does not cause deformation. Even in such a case, by adopting the configuration in which the bracket 108 is interposed, the action of releasing the distortion due to the thermal expansion of the optical pedestal 12 and the mounting plane 10
8A includes four supporting portions 34, 36 of the optical scanning device 10,
It is possible to realize the action of bringing 38 and 40 into contact with each other.

[0070]

As described above, the optical scanning device according to the first aspect of the invention has the above-mentioned structure, and therefore has the following effects. (1) By fixing the optical pedestal, the optical component can be automatically positioned vertically with respect to the mounting surface. (2) Even if the flatness between the support parts of the optical pedestal has a certain amount of deviation, it is possible to bring all of the support parts into contact with the mounting surface, and the floating support parts are fixed to the mounting surface. Will disappear. Therefore, it is less likely to be affected by vibration,
Vibration of the light beam is suppressed, and deterioration of image quality of the image forming apparatus can be prevented. (3) Distortion due to thermal expansion of the optical pedestal when the temperature rises can be released, and variation in optical alignment of optical components due to temperature change, that is, deviation of the optical axis of the light beam can be prevented.

Since the optical scanning device according to the second aspect has the above-mentioned configuration, it has an excellent effect that each supporting portion can be brought into contact with the mounting surface reliably and with equal force.

Since the optical scanning device according to the third aspect has the above-mentioned configuration, the optical component is supported in the high rigidity region, so that it has an excellent effect that variation of optical alignment due to vibration can be suppressed. .

Since the optical scanning device according to the fourth aspect has the above-mentioned structure, it has an excellent effect that the Fθ lens can be prevented from vibrating and the curvature and inclination of the scanning plane of the light beam can be prevented.

Since the optical scanning device according to the fifth aspect has the above-mentioned structure, it has an excellent effect that the angle change due to the vibration of the optical axis of the light beam emitted from the light source can be suppressed and banding can be prevented. .

Further, since the optical scanning device according to the sixth aspect has the above-mentioned structure, even if the rigidity of the mounting portion of the image forming apparatus is low, optical alignment due to vibration and thermal expansion of the optical scanning device can be performed. It is possible to suppress fluctuations, prevent deterioration of image quality of the image forming apparatus due to vibrations, and prevent fluctuations in optical alignment of optical components due to temperature changes, that is, deviations of the optical axis of the light beam.

[Brief description of drawings]

FIG. 1 is a plan view of an optical scanning device according to a first embodiment.

FIG. 2 is a vertical cross-sectional view of the optical scanning device according to the first embodiment showing a state before being fixed to an image forming apparatus.

FIG. 3 is a vertical cross-sectional view of the optical scanning device according to the first embodiment showing a state in which the optical scanning device is fixed to an image forming apparatus.

FIG. 4 is a bottom view of the optical scanning device according to the first embodiment.

FIG. 5 is a plan view of a frame of the image forming apparatus.

FIG. 6 is a plan view of the optical scanning device according to the first embodiment showing a state in which the optical scanning device is fixed to the image forming apparatus.

FIG. 7 is a plan view of an optical scanning device according to a second embodiment.

FIG. 8 is a vertical cross-sectional view of the optical scanning device according to the second embodiment showing a state before being fixed to the image forming apparatus.

FIG. 9 is a vertical cross-sectional view of the optical scanning device according to the second embodiment showing a state in which the optical scanning device is fixed to the image forming apparatus.

FIG. 10 is a bottom view of the optical scanning device according to the second embodiment.

FIG. 11 is a plan view of an optical scanning device according to a third embodiment.

FIG. 12 is a bottom view of the optical scanning device according to the third embodiment.

FIG. 13 is a bottom view of the optical scanning device according to the fourth embodiment.

FIG. 14 is a vertical cross-sectional view of an optical scanning device according to a fifth embodiment showing a state where the optical scanning device is fixed to an image forming apparatus.

FIG. 15 is a plan view of the optical scanning device according to the fifth embodiment, showing a state in which the optical scanning device is fixed to the image forming apparatus.

FIG. 16 is a plan view of the bracket.

[Explanation of symbols]

10 Optical scanning device 12 Optical pedestal 14A mounting plane 16 Light source (optical parts) 18 Collimator lens (optical parts) 20 cylinder lens (optical parts) 22 Rotating polygon mirror (optical parts) 24 1st Fθ lens (optical parts) 26 Second Fθ lens (optical component) 27 Cylinder lens (optical parts) 28 Mirror (optical component) 29 Light receiving element (optical component) 34 Support 36 Support 38 Support 40 Support 42 Fixed part 48 ribs 50 ribs 50A rib 60 gap 64 optical pedestal 66 quadrilateral area (high rigidity area) 68 Quadrilateral area (high rigidity area) 70 Quadrilateral area (high rigidity area) 72 Quadrilateral area (high rigidity area) 74 Quadrilateral area (high rigidity area) 76 Long and narrow groove area (low rigidity area) 77 Optical pedestal 78 Support 80 Support 82 Support 84 Support 86 Support 88 Support 90 Triangle area (high rigidity area) 92 Triangular area (high rigidity area) 94 triangular area (high rigidity area) 96 triangular area (high rigidity area) 98 Triangular area (high rigidity area) 100 triangular area (high rigidity area) 102 Long and narrow groove area (low rigidity area) 104 Optical pedestal 106 Support 108 bracket 108A mounting plane

Claims (6)

(57) [Claims] 1. An image forming apparatus is mounted on a mounting surface,
A plurality of optical components including a light source are mounted on an optical pedestal, and an optical scanning device for scanning a light beam emitted from the light source, wherein a plurality of optical positioning devices provided on the optical pedestal for performing vertical positioning with respect to the mounting surface are provided. A support portion; and a fixing portion provided on the optical pedestal and fixed to the mounting surface, wherein the optical pedestal is made of an elastically deformable material, and the fixing portion is attached to the mounting surface. Before fixing, there is a gap between the fixing portion and the mounting surface, and when the fixing portion is fixed to the mounting surface, at least a part of the optical pedestal is elastically deformed and the gap disappears. An optical scanning device, wherein all of the plurality of supporting parts are in contact with the mounting surface. 2. The optical scanning device according to claim 1, wherein there are at least three supporting portions, and the fixing portion is located at a substantially central portion of a polygon formed by the supporting portions. 3. A high-rigidity region whose rigidity is increased by a rib and a low-rigidity region whose rigidity is not increased by a rib are provided on the optical pedestal, and the optical component is supported by the high-rigidity region. Claim 1 or claim 2
The optical scanning device according to. 4. The optical scanning device according to claim 3, wherein one of the high-rigidity regions is provided with the fixing portion and a support point for supporting the Fθ lens in the optical component. 5. The optical scanning device according to claim 1, wherein one of the supporting portions is located near the light source. 6. The optical pedestal is attached and fixed to the image forming apparatus via a bracket having a material having a substantially same linear expansion coefficient as that of the attaching portion of the image forming apparatus and having sufficient rigidity. The optical scanning device according to any one of claims 1 to 5, wherein