JPH09230222A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanner capable of adjusting deviation in the position of a scanning line in a subscanning direction and restraining the change of optical path length. SOLUTION: This scanner is constituted so that light emitted from a light source is deflected by a deflection part and the optical path of the light is bent by a mirror 41 so as to scan a surface to be scanned with the light. Furthermore, the scanner is equipped with a holding part 44 holding the mirror 41 so that the mirror 41 may be inclined with a straight line in parallel with a main scanning direction including a point where the light is reflected as a center axis, and a supporting part 46 supporting the holding part 44. By inclining the mirror 41 with the straight line in parallel with the main scanning direction including the point where the light is reflected as the center axis and adjusting the attaching angle of the mirror 41, the position of the scanning line is adjusted without causing the deviation of the point where the light is reflected on the mirror 41.

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.

[0002]

2. Description of the Related Art Optical scanning devices include those used in electrophotographic image forming apparatuses. This optical scanning device deflects laser light emitted from a semiconductor laser by a polygon mirror to scan the photoconductor (scanned surface) and form an electrostatic latent image on the photoconductor.

In such an optical scanning device, in order to miniaturize the device, a mirror for bending the optical path of the laser light deflected by the polygon mirror is provided, and the semiconductor laser and the polygon mirror are arranged at positions close to the photoconductor. There is something.

However, in an optical scanning device equipped with a mirror that bends the optical path of laser light, if the mounting angle of the mirror shifts, the scanning line position in the sub-scanning direction for scanning the laser light on the photoconductor is displaced. At this time, since the position of the electrostatic latent image formed on the photoconductor is displaced in the sub-scanning direction, the position of the image transferred on the transfer paper is displaced. Particularly, in the color image forming apparatus, if the positions of the images are deviated, the colors cannot be superposed neatly, and the print quality is deteriorated.

Further, in order to correct the deviation of the scanning line position in the sub-scanning direction, it is necessary to adjust the mounting angle of the mirror. However, if the point where the laser beam is reflected is displaced during the adjustment,
The optical path length of the laser light changes. At this time, the focus position of the laser light is deviated from the photoconductor, and the diameter of the laser light scanned on the photoconductor is expanded. For this reason, it is not possible to clearly distinguish between the place where the laser light is irradiated and the place where the laser light is not irradiated, and a clear image cannot be obtained.

On the other hand, an image forming apparatus that can correct the scanning line position in the sub-scanning direction and the optical path length change has been considered.
It is described in Japanese Patent No. 142681. This image forming apparatus forms a registration mark for detecting a shift in scanning line position in the sub-scanning direction and a change in optical path length on a photoconductor, and transfers the registration mark to a conveyor belt. Then, the information about the shift of the scanning line position in the sub-scanning direction and the change in the optical path length is read from the registration mark transferred to the conveyor belt, and the actuator is driven based on the read information to drive the actuator and the mounting position of the mirror to the optical path of the laser beam. By adjusting, the deviation of the scanning line position in the sub-scanning direction and the change of the optical path length are corrected.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Laid-Open No.
In the optical scanning device described in Japanese Patent No. 142681,
Since it is necessary to provide an expensive actuator and detection element, there is a problem that miniaturization is difficult. Further, the information about the shift of the scanning line position and the change in the optical path length is read from the registration roller transferred to the conveyor belt, and the mounting position of the mirror with respect to the optical path of the laser light is adjusted based on the read information, which makes the control complicated. There is a problem.

[0008]

According to the first aspect of the present invention,
A deflection unit that deflects the light emitted from the light source to scan the light on the surface to be scanned and a mirror that bends the optical path of the light deflected by the deflection unit are provided, and the light is deflected by the deflection unit. In an optical scanning device that bends the optical path by the mirror and scans the light on the surface to be scanned, a straight line parallel to the main scanning direction, which is attached to the mirror and includes a point where the light is reflected, is a central axis. A holding unit that holds the mirror in a tilted state and a support unit that supports the holding unit are provided. Therefore, the holding unit holds the mirror in a state in which the mirror is tilted about the straight line parallel to the main scanning direction including the point where the light is reflected as the central axis, and the holding unit is supported by the supporting unit. As a result, when the mounting angle of the mirror is adjusted, it is possible to prevent the point on the mirror where the light is reflected from shifting, so that the change in the optical path length is suppressed. Further, since the mounting angle of the mirror can be adjusted, the deviation of the scanning line position in the sub-scanning direction can be adjusted.

According to a second aspect of the present invention, in the optical scanning device according to the first aspect, an elastic member for pressing the holding portion attached to the mirror against the supporting portion is provided, and the mirror uses the elastic member for the holding portion. The holding portion is pressed against the supporting portion, the mounting angle of the mirror is adjusted, and then the holding portion is adhered and fixed to the supporting portion. Therefore, by pressing the holding portion against the support portion with the elastic member, when adjusting the mounting angle of the mirror, the mirror can be held in a tilted state, which facilitates the work of adjusting the mounting angle of the mirror. Further, since it is possible to prevent the mounting angle of the mirror from changing, the mounting angle of the mirror can be maintained at the optimum position.

According to a third aspect of the present invention, in the optical scanning device according to the first or second aspect, the center of gravity of the mirror to which the holding portion is attached is positioned right below the central axis in the state in which the mirror is tilted. Therefore, when the holding portion is not fixed to the support portion, the mirror stands still in a tilted state, which facilitates adjustment of the mounting angle of the mirror. Further, since it is possible to prevent the mounting angle of the mirror from changing, the mounting angle of the mirror can be maintained at the optimum position.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical scanning device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 6 shows an image forming apparatus to which the optical scanning device of this embodiment is applied. First, the image forming apparatus 1 will be described. The image forming apparatus 1 is a color image forming apparatus that forms a color image on the transfer paper 2.

In the image forming apparatus 1, a transfer paper carrying belt 3 for carrying the transfer paper 2 is arranged at the center.
An image forming unit 4Y that forms an image of each color of yellow (Y), magenta (M), cyan (C), and black (B) on the upper surface side of the transfer paper transport belt 3 and transfers the image to the transfer paper 2. , 4M, 4C, 4B are sequentially arranged at equal intervals along the transfer direction of the transfer paper 2. Photoreceptors 5Y, 5M, 5C and 5B are rotatably provided in the image forming sections 4Y, 4M, 4C and 4B, respectively.
Above the image forming units 4Y, 4M, 4C, 4B, optical scanning units 6Y, 6M, 6C, 6B for exposing the photoconductors 5Y, 5M, 5C, 5B to form electrostatic latent images are arranged. ing.

Below the transfer paper transport belt 3, a paper supply unit 7 for supplying the transfer paper 2 is arranged. A fixing unit 8 for fixing the image transferred onto the transfer paper 2 is provided downstream of the transfer paper conveying belt 3 in the conveying direction of the transfer paper 2, and the transfer paper on which the image is fixed by the fixing unit. A paper discharge section 9 for discharging 2 is sequentially arranged.

Image forming sections 4Y, 4M, 4C, 4B
Forms an image corresponding to each color by an electrophotographic process. The image forming section 4Y for yellow, which forms a yellow image and transfers it to the transfer paper 2, has the photoreceptor 5Y.
Are provided rotatably. Around the photoconductor 5Y, a charger 10Y that uniformly charges the photoconductor 5Y,
A developing device 11Y that develops the electrostatic latent image formed by the optical scanning unit 6, a transfer roller 12Y that transfers the developed image to the transfer paper 2, and a cleaning device 13Y that cleans the photoconductor 5Y. A static eliminator 14Y for neutralizing the photoconductor 5Y is arranged. The other configurations of the image forming units 4M, 4C, and 4B are the same as the configurations of the image forming unit 4Y for yellow. Therefore, description of the image forming units 4M, 4C and 4B will be omitted.

The conveyor belt 3 is an endless belt which is wound around a driving roller 15 and a driven roller 16. The conveyor belt 3 is provided with the photoconductors 5Y, 5M, 5
C, 5B and the transfer rollers 12Y, 12M, 12C, 1
It is arranged so as to pass between 2B. A tension roller 17 that applies a predetermined tension to the conveyor belt 13 is arranged at a position where it comes into contact with the conveyor belt 3.
A motor (not shown) is connected to the drive roller 15. The drive roller 15 is rotated by the motor to move the conveyor belt 3 at a predetermined speed to the photoreceptor 5Y,
Move along 5M, 5C, 5B. An adsorption unit 18 that electrostatically adsorbs the transfer paper 2 to the conveyor belt 3 is arranged above the driven roller 16 so that the transfer paper 2 does not shift on the conveyor belt 3.

The paper feed section 7 is provided with a paper feed cassette 19 for stacking the transfer paper 2. Above the paper feed cassette 19, a paper feed roller 20 for feeding the transfer papers 2 one by one is arranged. The paper feed section 7 is formed with a transport path 21 for transporting the transfer paper 2 fed from the paper feed cassette 19 to the upper surface side of the transport belt 3. A transport roller 22 that transports the transfer paper 2 is arranged in the transport path 21. A registration roller 23 that conveys the transfer paper 2 to the conveyance belt 3 in synchronization with the rotation of the photoconductors 5Y, 5M, 5C, and 5B is arranged in the conveyance path 21.

In the fixing section 8, a fixing roller 24 for fixing the image on the transfer sheet 2 by heating and pressurizing the transfer sheet 2.
Is arranged.

A first paper discharge roller 2 for discharging the transfer paper 2 on which the image has been fixed by the fixing unit 8 to the paper discharge unit 9.
5 are arranged. First and second paper discharge trays 26, 27 for discharging the transfer paper 2 are provided on the downstream side of the first paper discharge roller 25 in the transport direction of the transfer paper 2. The first paper discharge tray 26 is formed on the upper part of the main body of the image forming apparatus 1. The second paper discharge tray 27 is a side surface of the main body of the image forming apparatus 1 (see FIG. 6).
It is formed on the left side. The first paper discharge roller 2
A paper discharge path 28 through which the transfer paper 2 is conveyed is formed between the sheet 5 and the first paper discharge tray 26. A switching claw 29 for switching the transport direction of the transfer sheet 2 and a second sheet discharge roller 30 for discharging the transfer sheet 2 are arranged in the sheet discharge path 28.

Therefore, in the image forming apparatus 1, when the start button (not shown) is pressed, the paper feed roller 20 and the transport roller 22 rotate, and the transfer papers 2 loaded in the paper feed cassette 19 are separated one by one. The paper is fed, fed, and conveyed along the conveyance path 21. Then, the photoconductors 5Y, 5
The registration roller 23 is synchronized with the rotation of M, 5C and 5B.
Thus, the transfer paper 2 is conveyed to the conveyor belt 3, and the transfer paper 2 is electrostatically adsorbed to the conveyor belt 3 by the adsorbing unit 18 so that the transfer paper 2 moves together with the conveyor belt 3.

At this time, yellow, magenta, cyan,
The optical scanning unit 6 based on the image information corresponding to each color of black
Each of the photoconductors 5Y, 5M, 5 by Y, 6M, 6C, 6B
C and 5B are exposed to form an electrostatic latent image. For example,
In the image forming unit 4Y for yellow, the photoconductor 5Y is uniformly charged by the charger 10Y, the photoconductor 5Y is exposed by the optical scanning unit 6Y based on the image information of yellow, and an electrostatic latent image is formed on the photoconductor 5Y. An image is formed. This electrostatic latent image is developed by the developing device 11Y, and the developed image is transferred to the transfer paper 2 on the conveyor belt 3 by the transfer roller 12Y.
After that, the photoconductor 5Y is cleaned by the cleaning device 13Y and discharged by the static eliminator 14Y to prepare for the next operation.

In the other image forming sections 4M, 4C and 4B, the photoconductors 5M, 5C and 5B are also based on the image information of each color.
Only the electrostatic latent image formed thereon is different, the same operation as that in the image forming unit 4Y for yellow described above is performed to form an image of each color, and the transfer paper 2 that moves together with the transport belt 3 is formed. Transferred in sequence. Therefore, the image forming unit 4
The description of the operations of M, 4C, and 4B is omitted.

Then, the transfer paper 2 on which the image of each color is transferred
Is separated from the conveyor belt 3 on the driving roller 15 having a small radius and conveyed to the fixing unit 8. Transfer paper 2 at fixing unit 8
The image transferred onto the paper is fixed, and the transfer paper 2 is discharged to the first or second paper discharge tray 26, 27.

Next, the photoconductor 5Y provided in the image forming portion 4Y for yellow is exposed to expose the photoconductor 5Y.
The optical scanning unit 6Y for yellow that forms an electrostatic latent image on Y
Will be described with reference to FIGS. 2 and 3. The optical scanning unit 6Y
Drives the semiconductor laser 31, which is a light source, based on the yellow image information to emit laser light from the semiconductor laser 31 at a predetermined timing, and the laser light is deflected by the deflection unit 32.
The laser light is deflected to scan the photoconductor 5Y, which is the surface to be scanned, with laser light.

As shown in FIG. 3, a collimator lens 3 is provided between the semiconductor laser 31 and the deflection section 32 along the optical path of the laser light emitted from the semiconductor laser 31.
3, a slit 34, a cylinder lens 35, a first mirror 36, and a plano-convex lens 37 are arranged. The collimator lens 33 converts the laser light emitted from the semiconductor laser 31 into substantially parallel light. The slit 34 allows only a laser beam having a predetermined width to pass through. The cylinder lens 35 has power only in the sub-scanning direction (the direction perpendicular to the paper surface in FIG. 3) and collects light in the sub-scanning direction. The plano-convex lens 37 collects light in the main scanning direction (vertical direction in FIG. 3).

The deflecting unit 32 has the plano-convex lens 37.
A polygon mirror 38 having a reflecting surface that reflects the laser light that has passed therethrough is disposed. The polygon mirror 38
A scanner motor 39 that rotates the polygon mirror 38 and changes the incident angle of the laser light incident on the reflecting surface within a predetermined range is connected to the.

As shown in FIG. 2, the optical scanning unit 6Y includes:
Second and third mirrors 40 and 41 that bend the optical path of the laser light deflected by the deflection unit 32, and a correction lens 42 that transmits the laser light reflected by the third mirror 41 are arranged. . The correction lens 42 is
Both the entrance and exit surfaces are aspherical surfaces, are formed by resin formation, and are formed long in the main scanning direction.

The optical scanning unit 6Y is provided with a semiconductor laser driving unit (not shown) for driving the semiconductor laser 31 based on image information.

Further, the reflecting surface of the polygon mirror 38 is related to the correcting lens 42 in the sub-scan section.
It is formed so as to have a conjugate relationship with the photoconductor 5Y, and is formed so as not to cause an angular error for each reflecting surface with respect to the rotation axis of the polygon mirror 38, that is, so-called surface tilt.

Therefore, in the optical scanning unit 6Y, the semiconductor laser 31 is driven by the semiconductor laser driving unit based on the image information for yellow and emits the laser light at a predetermined timing. The laser light emitted from the semiconductor laser 31 is
The light enters the reflecting surface of the polygon mirror 38 through the collimator lens 33, the slit 34, the cylinder lens 35, the first mirror 36, and the plano-convex lens 37. At this time, the polygon mirror 38 is rotated by the scanner motor 39, the incident angle of the laser light incident on the reflecting surface changes within a predetermined range, and the laser light reflected by the reflecting surface is deflected. afterwards,
The laser light reflected by the second and third mirrors 40 and 41 scans the photoconductor through the correction lens 42.

At this time, the field curvature and the Fθ characteristic are corrected by the combination of the shape of the reflecting surface of the polygon mirror 38 and the aspherical shape of the correction lens.

The configuration and operation of the other optical scanning units 6M, 6C, 6B are the same as those of the optical scanning unit 6Y for yellow, except that the timing of emitting the laser light based on the image information of each color is different. . Therefore, the other optical scanning unit 6
A description of M, 6C and 6B is omitted.

The third mirror 41 will be described with reference to FIGS. 1, 4 and 5. The third mirror 41 is a column 4
3 supported. Holding parts 44 are attached to both ends of the third mirror 41. A columnar portion 45 is formed on the holding portion 44. The column 43
At the upper end of V, which is a support portion that supports the columnar portion 45,
A groove 46 is formed. A leaf spring 47, which is an elastic member for pressing the columnar portion 45 against the V-shaped groove 46, is attached to the column 43.

As shown in FIG. 1, the holding section 44 has the third mirror so that the straight line parallel to the main scanning direction including the point where the laser beam is reflected and the central axis of the cylindrical section 45 coincide with each other. It is adhered and fixed to 41.

At one end of the cylindrical portion 45, a jig receiving portion 48 is formed which is held by the claw of an existing adjusting jig when adjusting the mounting angle of the third mirror 41. Since common holding parts 44 are attached to both ends of the third mirror 41, when the third mirror 41 is tilted so that the laser light is reflected in a predetermined direction, the third holding part 44 is attached. The jig receiving portion 48 formed on one end side of the mirror 41 becomes longer in the vertical direction, and the jig receiving portion 48 formed on the other end portion of the third mirror 41 extends in the horizontal direction. become longer. Therefore, when adjusting the mounting angle of the third mirror 41, only the jig receiving portion 48 formed on one end side of the third mirror 41 and long in the vertical direction is used.

The third mirror 41 and the holding portion 44
When the third mirror 41 is tilted so that the laser light is reflected in a predetermined direction, the center of gravity of the third mirror 41 to which the holding portion 44 is attached is the center axis of the cylindrical portion 45. It is formed so as to be positioned vertically below the extension line.

The leaf spring 47 is formed with an engaging portion 49 for engaging the leaf spring 47 with the column 43. The locking portion 49 has a claw portion 50 protruding toward the column 43.
Are formed.

In the third mirror 41, the column portion 45 is V-shaped groove 46 with an adhesive (not shown) with the mounting angle adjusted so that the laser beam is reflected in a predetermined direction.
It is glued and fixed. The method of adjusting the mounting angle of the third mirror 41 is a method of adjusting the mounting angle of the mirror while observing the position of the laser beam scanning in the sub-scanning direction using an existing adjustment jig. An anaerobic adhesive, an instant adhesive or a photo-curable adhesive is used as the adhesive.

As described above, the holding portion 44 is attached to the third mirror so that the straight line parallel to the main scanning direction including the point where the laser light is reflected and the central axis of the cylindrical portion 45 coincide with each other. Is supported by the V-shaped groove 46, the third mirror 41 can be rotated about a straight line parallel to the main scanning direction including the point where the laser light is reflected, and the third mirror 41 can be rotated. When adjusting the mounting angle, it is possible to prevent the point at which the laser light from the third mirror 41 is reflected from being displaced, so that the change in the optical path length is suppressed and the mounting angle of the third mirror is adjusted. Therefore, the shift of the scanning line position in the sub-scanning direction is adjusted. Furthermore, since the columnar portion 45 is pressed against the V-shaped groove 46 by the leaf spring 47, the third mirror 41 can be held in a tilted state when adjusting the mounting angle of the third mirror 41.
The work of adjusting the mounting angle of the third mirror 41 becomes easy.
Further, the center of gravity of the third mirror 41 to which the holding portion 44 is attached is positioned vertically below the extension line of the central axis of the columnar portion 45 with the third mirror 41 tilted. When the third mirror 41 is not fixed, the third mirror 41 stands still in a tilted state, which facilitates adjustment of the mounting angle of the third mirror. Furthermore, the mounting angle of the third mirror 41 changes due to gravity while the adhesive cures, and the mounting angle of the third mirror 41 changes due to extra residual stress generated when the adhesive cures. Therefore, the mounting angle of the third mirror 41 is kept at an optimum angle.

In the embodiment of the present invention, the holding portion 44 in which the portion contacting the third mirror 41 is formed to have a substantially L-shaped cross section has been described, but the portion contacting the third mirror 41 is described. The shape is not limited to the substantially L-shaped cross section, and the shape of the portion contacting the third mirror 41 may be, for example, as shown in FIG. A notch 52 may be formed in the cutout.

Further, in the embodiment of the present invention, the V-shaped groove 46 is described as the supporting portion, but the supporting portion is V-shaped.
The holding portion 44 is not limited to the groove 46, and the holding portion 44 in which the portion contacting the support portion is the column portion 45 has been described, but the holding portion is not limited to the one having the column portion 45. The shape of the supporting portion and the holding portion is not limited as long as the third mirror 41 can be supported so that the third mirror 41 is tilted about a straight line parallel to the main scanning direction including the point where the laser light is reflected. Such a shape may be used. For example, a U-shaped groove may be formed as the supporting portion. Further, a hole may be formed in the column 43 as a supporting portion. Further, a columnar portion protruding toward the third mirror 41 side may be formed as the support portion, and a V-shaped or U-shaped recessed portion of the lower opening that abuts the columnar portion may be formed in the holding portion. Further, when the columnar portion is formed as the support portion, a cylindrical concave portion into which the columnar portion is fitted may be formed in the holding portion.

Further, in the embodiment of the present invention,
Although the holding members 44 are individually attached to both ends of the third mirror 41, the holding members 4 attached to both ends of the third mirror 41 if the central axis of the columnar portion 45 is on the same straight line.
4 may be integrally formed.

Further, in the embodiment of the present invention, the third mirror 4 is arranged so that the laser light is reflected in a predetermined direction.
Although the holding portion 44 formed so that the jig receiving portion 48 formed on one end side of the third mirror 41 is lengthened in the vertical direction when the first mirror 1 is tilted, the laser light is predetermined. When the third mirror 41 is tilted so as to be reflected in the direction of, the jig receiving portions 48 of the holding portions 44 attached to both ends of the third mirror 41 may be formed to be long in the vertical direction. .

Further, in the embodiment of the present invention,
Although the leaf spring 47 has been described as the elastic member, the elastic member is not limited to the leaf spring 47, and the elastic member is
It suffices if the holding portion can be pressed against the support portion.

[0044]

According to the first aspect of the present invention, the holding section holds the mirror in a state in which the mirror is inclined with a straight line parallel to the main scanning direction including a point where light is reflected as a central axis, and the holding section. Is supported by the support portion. As a result, it is possible to prevent the point where the light is reflected from shifting when adjusting the mounting angle of the mirror, so that it is possible to suppress the change in the optical path length. Moreover, since the mounting angle of the mirror can be adjusted, the shift of the scanning line position in the sub-scanning direction can be adjusted.

According to the second aspect of the present invention, since the holding portion is pressed against the support portion by the elastic member, the mirror can be held in a tilted state when adjusting the mounting angle of the mirror. This makes it easy to adjust the mounting angle of. Further, since it is possible to prevent the mounting angle of the mirror from changing, the mounting angle of the mirror can be maintained at an optimum position.

According to the third aspect of the present invention, since the center of gravity of the mirror to which the holding portion is attached is positioned right below the center axis in the tilted state of the mirror, the holding portion is not fixed to the support portion. At this time, since the mirror stands still in a tilted state, it becomes easy to adjust the mounting angle of the mirror. Further, since it is possible to prevent the mounting angle of the mirror from changing, the mounting angle of the mirror can be maintained at an optimum position.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing a part of an optical scanning device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing an optical scanning device.

FIG. 3 is a vertical sectional side view showing an optical scanning device.

FIG. 4 is an exploded perspective view showing a support structure for a mirror.

FIG. 5 is a perspective view showing a support structure of a mirror.

FIG. 6 is a vertical sectional front view showing a color image forming apparatus including an optical scanning device.

FIG. 7 is a perspective view showing a modified example of a holding unit.

[Explanation of symbols]

 5Y Scanned surface 5M Scanned surface 5C Scanned surface 5B Scanned surface 31 Light source 32 Deflection part 41 Mirror 44 Holding part 46 Support part 48 Elastic member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Murakami 6-78 Minamimachi, Mishima-shi, Shizuoka Tech Institute of Technology Co., Ltd. (72) Masayuki Satomi 6-78 Minamimachi, Mishima, Shizuoka TEC Inside the technical laboratory

Claims (3)

[Claims] 1. A deflection unit for deflecting light emitted from a light source to scan the irradiation surface with the light, and a mirror for bending an optical path of the light deflected by the deflection unit, In an optical scanning device that deflects light by a deflecting unit, bends the optical path by the mirror, and scans the light on the surface to be scanned, the optical scanning device is attached to the mirror and is parallel to a main scanning direction including a point where the light is reflected. An optical scanning device comprising: a holding unit that holds the mirror in a state where the mirror is tilted about a straight line as a central axis; and a support unit that supports the holding unit. 2. An elastic member for pressing a holding part attached to a mirror against a supporting part, wherein the mirror presses the holding part against the supporting part with the elastic member, and adjusts a mounting angle of the mirror, 2. The optical scanning device according to claim 1, wherein the holding portion is fixed to the supporting portion by bonding. 3. The optical scanning device according to claim 1, wherein the center of gravity of the mirror to which the holding unit is attached is positioned right below the central axis in the tilted state of the mirror.