JP4815372B2 - Optical element unit, optical scanning apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to an optical element unit including an optical element such as a lens and a mirror and an optical element holding unit that holds the optical element, an optical scanning device including the optical element unit, and an image forming apparatus.

Conventionally, irradiation light emitted from a light source is guided to a deflector using an imaging lens, and the irradiation light scanned by the deflector is condensed on a surface to be scanned using a scanning imaging element A scanning device is used in an image forming apparatus such as a printer. An optical scanning device provided in an image forming apparatus is used as an image writing device that collects irradiated light on a surface of a photosensitive member as a surface to be scanned and forms a latent image on the surface of the photosensitive member. Some optical scanning devices have optical elements such as long lenses and mirrors in which the scanning direction of laser light corresponding to the main scanning direction on the photosensitive member is the longitudinal direction in the optical system.
If there is an error in the optical system of the optical scanning device, the scanning line that scans the surface of the photoconductor scans the surface of the photoconductor. It is desirable that However, due to errors in the manufacturing accuracy of the optical elements that make up the optical system of the optical scanning device (such as bending of the scanning lens bus line and reduction in surface accuracy of the folding mirror) and assembly errors that occur when the optical elements are assembled in the housing It is difficult to manufacture the optical scanning device without error. For this reason, it is difficult to eliminate defects in scanning line bending in a normal manufacturing process such as in a factory.
For such problems, the scanning member is corrected by adjusting the bending state of the long lens with the adjustment member provided in the lens holder that holds the long lens of the optical elements that make up the optical system. Conventionally proposed optical scanning devices have been proposed.

  In Patent Document 1, a housing as a lens holder that is a lens holding unit supports the lower side of the central portion in the scanning direction of the long lens, and is adjusted as an adjustment member that can be pressed from above the both ends of the long lens. An optical scanning device with a screw is described. In this optical scanning device, the end of the linear long lens can be pushed downward by tightening the adjusting screw. For this reason, it is possible to adjust the shape of the long lens from a linear shape to a convex shape by adjusting the left and right adjustment screws.

The scanning line bending due to errors in manufacturing the optical scanning device changes the direction and degree of bending of the scanning lines due to accumulation of errors such as component accuracy errors and assembly errors. For this reason, even when the scanning line bend can be corrected by adjusting the long lens to have a downward convex shape, the scanning line bend can be corrected by adjusting the long lens to have a convex shape upward. It may happen that it can be corrected.
However, in the optical scanning device described in Patent Literature 1, the curved state of the long lens can be adjusted from the linear state to the upwardly convex shape, but the long lens is curved downward. It cannot be a state. For this reason, in the optical scanning device described in Patent Document 1, it is not possible to correct scanning line bending that can be corrected by adjusting the long lens to have a downwardly convex shape.

  The configuration shown in FIG. 4 of Patent Document 2 supports the lower side of both ends in the scanning direction of the long lens by two projections provided in the housing of the optical scanning device, and the upper projection of the long lens and A support spring is provided at the opposite position. Furthermore, the upper side of the center part of the long lens is pressed by a pressing spring fixed to the housing, the lower end of the center part of the long lens is in contact with the tip of the adjusting screw, and the adjusting screw is the long lens in the housing. The protruding length to the side is adjustable.

In the configuration shown in FIG. 4 of Patent Document 2, the long lens is vertically positioned with respect to the housing by pressing both ends of the long lens in the scanning direction against the protrusions by the elastic force of the support spring. . Then, by adjusting the protruding length of the adjusting screw into the housing, the vertical position of the central portion of the long lens with respect to the housing can be adjusted. Specifically, by adjusting the long lens so that the protruding length of the adjustment screw is increased from a linear state, the tip of the adjustment screw pushes up the center of the long lens, and the long lens is convex upward It becomes. On the other hand, by adjusting the long lens so that the protruding length of the adjusting screw is shortened from the linear state, the pressing spring pushes down the central portion of the long lens, and the long lens becomes convex downward.
As described above, with the configuration shown in FIG. 4 of Patent Document 2, the curved state of the long lens can be adjusted to an upwardly convex state or a downwardly convex state. For this reason, it is possible to correct both the scan line curve that can be corrected by making the long lens convex upward, and the scan line curve that can be corrected by making the long lens convex downward, and adjust the scan line curve. The possible range becomes wider.

JP 2004-54146 A JP 09-292580 A

However, in the configuration shown in FIG. 4 of Patent Document 2, the vertical position of the central portion of the long lens in the scanning direction with respect to the lens holding means varies depending on the curved state.
The optical scanning device is generally designed so that laser light passes through the center in the direction corresponding to the sub-scanning direction of the lens (the vertical direction in the case of the long lens in FIG. 4 of Patent Document 2). Depending on the characteristics of the lens, if the position where the laser beam passes is deviated from the center position in the direction corresponding to the sub-scanning direction of the lens, the scanning line irradiated on the surface of the photoreceptor is distorted. There was a risk of it occurring. Further, as in the configuration of FIG. 4 of Patent Document 2, the central portion can be displaced in both directions corresponding to the sub-scanning direction with respect to both ends positioned with respect to the lens holding member. . Since the configuration of Patent Document 2 can be adjusted from a linear shape to a convex shape in both the up and down directions, the center of the lens is displaced in the sub-scanning direction, and the linear shape is up or down. The displacement width in the direction corresponding to the sub-scanning direction of the central portion of the lens is larger than that of a configuration in which the curved state can be adjusted so that only one of them is convex. Thereby, the width | variety from which the position which a laser beam passes with respect to the center position of the direction corresponding to the subscanning direction of a long lens shifts also becomes large.

  In the above description, the configuration for adjusting the bending state of the long lens has been described. However, the optical element capable of correcting the scanning line bending by adjusting the bending state is not limited to the lens. For example, a similar problem may occur even when an optical system passes through a long concave mirror and the curvature of the scanning line is corrected by adjusting the curved state in the direction corresponding to the sub-scanning direction of the concave mirror.

  The present invention has been made in view of the above problems, and an object of the present invention is to adjust the curved state of the optical element to be convex in either direction in the direction corresponding to the sub-scanning direction on the surface to be scanned. An optical element unit that can suppress the displacement of the light passing position from the light source with respect to the center position in the direction corresponding to the sub-scanning direction of the optical element. An apparatus and an image forming apparatus are provided.

In order to achieve the above object, an invention according to claim 1 is directed to an optical element that forms an image of irradiation light that has been deflected and scanned on a surface to be scanned, a holding member that holds the optical element, and an auxiliary element on the surface to be scanned. in the optical element unit and a regulation to that bay song adjusting means a curved state of the optical element in the direction corresponding to the scanning direction, the direction corresponding to the sub-scanning direction relative to the holding member in the scanning direction central portion of the optical element A central portion fixing means for fixing the position of the optical element, and a curvature adjusting portion for applying a force in a direction corresponding to the sub-scanning direction on both sides of the scanning direction with respect to the central portion in the scanning direction of the optical element. The position of the holding member in the scanning direction is fixed, the pressure adjusting member of the optical element is pressed from one of the directions corresponding to the sub-scanning direction, and a pressing member capable of adjusting the pressing amount; Press member and optical element And an elastic member that applies an elastic force toward the pressing member side with respect to the bending amount adjusting portion of the optical element, and adjusts the pressing amount of the pressing member. The position of the curvature adjusting unit in the direction corresponding to the sub-scanning direction with respect to the position of the central part in the scanning direction is displaced, and the position of the end part in the scanning direction of the optical element is changed with respect to the position of the central part in the scanning direction of the optical element. The optical element and the holding member are different in the amount of change in the scanning direction due to thermal expansion, and the pressure is changed by displacing the optical element in both directions corresponding to the sub-scanning direction. A sliding member that facilitates sliding between the member and the optical element is provided between the pressing member and the optical element .
Also, the second aspect of the present invention is an optical element unit according to claim 1, the pressing member is an adjusting screw, corresponding to the subscanning direction with respect to the holding member at the tip portion by rotating the adjustment screw The direction position is displaced, and the bending adjustment portion of the optical element is pressed by the tip of the adjustment screw .
Also, the invention of claim 3, the optical element unit according to claim 1 or 2, a central portion for positioning the scanning direction of the scanning direction center portion of the scanning direction central portion and the optical element of the holding member Positioning means is provided.
The invention of claim 4 is an optical element unit according to claim 1, 2 or 3, the central portion fixing means, in a direction corresponding to the sub-scanning direction with respect to the scanning direction central portion of the optical element An abutting member that abuts from one side, and a central elastic member that opposes the abutting member and the optical element across the optical element and applies an elastic force to the abutting member side with respect to the central part of the optical element, The abutting member and the central elastic member are fixed to the holding member.
Further, characterized in that the invention of claim 5, claim 1, in the optical element unit 4 was 3 or, the optical element is an elongated lens scanning direction of the irradiation light incident is longitudinal It is what.
According to a sixth aspect of the present invention, there is provided a light having a light source, a light deflecting unit that deflects and scans the irradiation light from the light source, and an optical system that forms an image of the irradiation light from the light deflecting unit on the surface to be scanned. in the scanning device, the optical system is characterized in that, including the claims 1, 2, 3, 4 or 5 optical element unit.
Further, the invention according to claim 7 is the optical scanning device according to claim 6 , wherein the optical element unit is centered on a unit rotation axis whose axis direction is perpendicular to the direction corresponding to the scanning direction and the sub-scanning direction. The optical scanning unit is swingable with respect to the housing, and the inclination of the optical element unit with respect to the housing around the unit rotation axis can be adjusted.
The invention of claim 8 is the optical scanning apparatus according to claim 7, said unit rotation axis is characterized in that has been found integrally formed with the holding member of the optical element unit.
According to a ninth aspect of the present invention, in the optical scanning device according to the eighth aspect , the unit rotary shaft is positioned with respect to a rotary shaft support member fixed to the housing.
According to a tenth aspect of the present invention, a latent image is formed on the surface of the latent image carrier by irradiating the surface of the latent image carrier with scanning light using an optical scanning means, and the latent image is developed. In the image forming apparatus for forming an image by finally transferring the image obtained in (1) onto a recording material, the optical scanning device according to claim 6, 7, 8 or 9 is used as the optical scanning unit. To do.

According to the first to tenth aspects of the present invention, the position in the direction corresponding to the sub-scanning direction with respect to the holding member at the center in the scanning direction of the optical element can be fixed by the center fixing means. For this reason, it can suppress that the position through which the light irradiated from the light source passes is shifted from the center position of the optical element in the direction corresponding to the sub-scanning direction. Further, since the curvature adjusting means can displace the position of the end portion in the scanning direction of the optical element in both directions in the direction corresponding to the sub-scanning direction with respect to the position of the central portion in the scanning direction, Adjustment that makes the curved state of the optical element convex in either direction can be performed.

According to the first to tenth aspects of the present invention, it is possible to adjust the direction corresponding to the sub-scanning direction so that the curved state of the optical element is convex in either direction, and the direction corresponding to the sub-scanning direction. There is an excellent effect that it is possible to suppress the shift of the position through which the light irradiated from the light source passes with respect to the center position of the optical element.

Hereinafter, an embodiment in which the present invention is applied to a printer 100 as an image forming apparatus will be described.
The printer 100 according to the present embodiment will be described by taking a so-called intermediate transfer type tandem image forming apparatus as an example, but is not limited thereto.
FIG. 2 is a schematic configuration diagram illustrating the printer 100 according to the present embodiment.
The printer 100 includes an apparatus main body 1 and a paper feed cassette 2 that can be pulled out from the apparatus main body 1. In the central portion of the apparatus main body 1, image forming stations 3Y, 3C, and 3C for forming toner images (visible images) of respective colors of yellow (Y), cyan (C), magenta (M), and black (K). 3M, 3K. Hereinafter, the subscripts Y, C, M, and K of the respective symbols indicate members for yellow, cyan, magenta, and black, respectively.

FIG. 3 is a configuration diagram showing one schematic configuration of the image forming stations 3Y, 3C, 3M, and 3K. Since the image forming stations 3Y, 3C, 3M, and 3K use different colors of toner and have the same basic configuration, FIG. 3 omits the subscripts Y, C, M, and K that indicate colors. .
As shown in FIGS. 2 and 3, the image forming station 3 includes a drum-shaped photoconductor 10 as a latent image carrier that rotates in the direction of arrow S in the drawing. The photoconductor 10 includes an aluminum cylindrical base and an OPC (organic photo semiconductor) photosensitive layer that covers the surface of the cylindrical base. The image forming station 3 includes a charging device 11 that charges the surface of the photoconductor 10 around the photoconductor 10, and a developing device 12 as a developing unit that develops a latent image formed on the photoconductor 10. Further, a cleaning device 13 for cleaning residual toner remaining on the photoreceptor 10 after the primary transfer is provided.

  As shown in FIG. 2, below the image forming stations 3Y, 3C, 3M, and 3K, an optical scanning device 4 that can irradiate the photoconductors 10Y, 10C, 10M, and 10K with the writing light L is provided. Above the image forming stations 3Y, 3C, 3M, and 3K, an intermediate transfer unit 5 including an intermediate transfer belt 20 to which toner images formed on the photoreceptors 10Y, 10C, 10M, and 10K are transferred. I have. Further, a fixing unit 6 is provided for fixing the toner image transferred to the intermediate transfer belt 20 to the transfer paper P as a recording material. In addition, toner bottles 7Y, 7C, 7M, and 7K that store toners of respective colors of yellow (Y), cyan (C), magenta (M), and black (K) are loaded on the upper portion of the apparatus main body 1. . The toner bottles 7 </ b> Y, 7 </ b> C, 7 </ b> M, and 7 </ b> K are configured to be detachable from the apparatus main body 1 by opening a paper discharge tray 8 formed on the upper part of the apparatus main body 1.

The optical scanning device 4 deflects writing light (laser light) L emitted from a laser diode as a light source by a polygon mirror or the like, and scans it on the surfaces of the photoconductors 10Y, 10C, 10M, and 10K as scanning surfaces. Irradiate while. Detailed description of the optical scanning device 4 will be described later.
The intermediate transfer belt 20 of the intermediate transfer unit 5 is wound around a driving roller 21, a tension roller 22 and a driven roller 23, and is driven to rotate counterclockwise in the drawing at a predetermined timing. The intermediate transfer unit 5 includes a primary transfer roller 24 that transfers the toner image formed on each photoconductor 10 to the intermediate transfer belt 20. The intermediate transfer unit 5 cleans the secondary transfer roller 25 that transfers the toner image transferred onto the intermediate transfer belt 20 onto the transfer paper P, and the transfer residual toner on the intermediate transfer belt 20 that has not been transferred onto the transfer paper P. A belt cleaning device 26 is provided.

Next, a process for obtaining a color image in the printer 100 will be described.
First, in each color image forming station 3, the photoreceptor 10 is uniformly charged by the charging device 11. Thereafter, the laser beam L is scanned and exposed by the optical scanning device 4 based on the image information, and a latent image is formed on the surface of each photoconductor 10. The latent image on the photoconductor 10 is developed with toner of each color carried on the developing roller 15 rotating in the direction of arrow T in the drawing of the developing device 12, and is visualized as a toner image. The toner image on the photoconductor 10 is sequentially transferred onto the intermediate transfer belt 20 that is rotated counterclockwise by the action of each primary transfer roller 24. The image forming operation of each color at this time is shifted in timing from the upstream side in the moving direction of the intermediate transfer belt 20 toward the downstream side so that the toner image is transferred to the same position on the intermediate transfer belt 20. Executed. The surface of the photoreceptor 10 after the primary transfer is finished is cleaned by the cleaning blade 13a of the cleaning device 13 and is prepared for the next image formation. The toner filled in the toner bottles 7Y, 7C, 7M, and 7K is placed in the developing devices 12Y, 12C, 12M, and 12K of the image forming stations 3Y, 3C, 3M, and 3K by a conveyance path (not shown) as necessary. A fixed amount is supplied.

  On the other hand, the transfer paper P in the paper feed cassette 2 is conveyed into the apparatus main body 1 by the paper feed roller 27 disposed in the vicinity of the paper feed cassette 2 and reaches the registration roller pair 28. Then, the secondary transfer roller 25 is conveyed by the registration roller pair 28 to the secondary transfer portion facing the tension roller 22 with the intermediate transfer belt 20 interposed therebetween at a predetermined timing. Then, the toner image formed on the intermediate transfer belt 20 is transferred to the transfer paper P in the secondary transfer portion. The transfer paper P onto which the toner image has been transferred passes through the fixing unit 6 to be fixed, and is discharged to the paper discharge tray 8 by the discharge roller 29. Similar to the photoconductor 10, residual toner remaining on the intermediate transfer belt 20 is cleaned by a belt cleaning device 26 that contacts the intermediate transfer belt 20.

Next, the configuration of the optical scanning device 4 will be described.
FIG. 4 is an explanatory perspective view of the optical scanning device 4 applicable to the present embodiment. 4 shows a state in which the photosensitive member 10 is disposed below the optical scanning device 4, but FIGS. 2 and 3 are used by inverting the optical scanning device 4 and the photosensitive member 10 of FIG. This can be applied to the printer 100 described above.
In FIG. 4, an optical element group 60M that forms an image of the laser light from the LD unit 70M on the photoconductor 10M that forms a magenta toner image, and a photoconductor 10C that forms a cyan toner image from the LD unit 70C. An optical element group 60C that forms an image of laser light is shown. The optical path from the magenta LD unit 70M to the photoconductor 10M and the optical path from the cyan LD unit 70C to the photoconductor 10C share the polygon mirror 80 as light deflecting means. . In FIG. 4, for the yellow and black optical paths not shown, the polygon mirror 80 may be shared as the light changing means, or the laser beam from the light source may be deflected and scanned by a separately provided polygon mirror. good.

In FIG. 4, an optical path of a laser beam for forming a magenta toner image from the LD unit 70M to the photoconductor 10M, and a laser beam for forming a cyan toner image from the LD unit 70C to the photoconductor 10C. Since the optical paths of these have the same configuration, description will be made here with M and C indicating the corresponding colors omitted.
In the optical scanning device 4, the laser light emitted from the LD unit 70 including the first light source 71 and the second light source 72 is imaged on the surface of the photoconductor 10 that is an image carrier.
On the optical path from the LD unit 70 to the photoconductor 10, a polygon mirror 80 that is a light deflecting unit, a first scanning lens 61, a second scanning lens 62, a controlled lens 41 that is a third scanning lens, and a first return. An optical element group 60 including a mirror 63, a second folding mirror 64, a third folding mirror 65, and the like is provided. As the first light source 71 and the second light source 72 included in the LD unit 70, a semiconductor laser element that emits a single beam or a semiconductor laser array element that emits a plurality of beams can be used. The first scanning lens 61, the second scanning lens 62, and the adjusted lens 41, which is the third scanning lens, are long lenses in which the scanning direction of the incident laser light L scanned by the polygon mirror 80 is the longitudinal direction. It is.

As shown in FIG. 4, the optical system of the optical scanning device 4 is composed of a plurality of optical elements. All of these optical elements are manufactured without error, and assembled into the housing of the optical scanning device 4 without error. It is difficult to manufacture the device 4. Further, due to the accumulation of manufacturing errors and assembly errors of the optical elements, there may occur a scanning line curve in which the scanning line for scanning the surface of the photoconductor 10 with the laser light L is not a straight line but a curved line. In addition, in the accumulation of errors, a scanning line tilt may occur in which the scanning line on the surface of the photoconductor 10 is not parallel to the rotation axis of the photoconductor 10 but is tilted.
The optical scanning device 4 corrects the scanning line bending and the scanning line inclination by performing various adjustments in the adjusted lens 41 that is the third scanning lens.

Next, the adjusted lens 41 which is a third scanning lens will be described.
FIG. 5 is a perspective explanatory view of a lens unit 200 as an optical element unit having a lens 41 to be adjusted as an optical element and a lens holder 40 as a holding member for holding the lens 41 to be adjusted.
FIG. 6 is an exploded perspective view of the lens unit 200 shown in FIG.
An arrow A direction in FIG. 5 is a direction in which the laser light L incident on the adjusted lens 41 is scanned by the polygon mirror 80 and is defined as a “scanning direction” in the present embodiment. Further, the direction of arrow C in FIG. 5 is a direction substantially parallel to the optical axis of the laser light L transmitted through the controlled lens 41, and is defined as an “optical axis direction” in the present embodiment. Further, an arrow B direction in FIG. 5 is a direction orthogonal to the scanning direction and the optical axis direction, and corresponds to the sub-scanning direction on the photoconductor 10, and is referred to as “sub-scanning direction” in the present embodiment. Define.
Further, the mounting direction of the magenta adjusted lens 41M and the cyan adjusted lens 41C are opposite to each other, but since the configuration itself is the same, the description of the adjusted lens 41 also shows the corresponding color M. The explanation will be made by omitting and C.

As shown in FIGS. 5 and 6, the adjusted lens 41 is held by a lens holder 40. Specifically, the lens holder 40 includes a holder main body 43 on which the adjustable lens 41 is placed, and a top plate 42 that sandwiches the adjustable lens 41 placed on the holder main body 43 from above.
A projection 46 for use in alignment of the lens holder 40 in the scanning direction is provided at the center of the lens, which is the center of the adjusted lens 41 in the scanning direction (arrow A direction). Further, projecting pieces 50 for use in alignment in the optical axis direction (arrow C direction) with respect to the lens holder 40 are provided at both lens end portions that are scanning direction end portions of the adjusted lens 41.

At the center portion of the holder body, which is the center portion of the holder body 43, a restricting portion 47 having a groove portion 47b that engages with the protruding portion 46 of the adjusted lens 41 is provided. Since the position of the adjusted lens 41 in the scanning direction with respect to the lens holder 40 is regulated by the engagement between the protrusion 46 and the groove 47b of the regulating part 47, the reference surfaces of both are processed with high accuracy in advance. With such a configuration, the center of the holder body and the center of the lens are positioned in the scanning direction, and the protrusion 46 of the lens 41 to be adjusted and the groove 47b of the restricting portion 47 constitute a center positioning means. ing.
The lens central portion of the adjusted lens 41 is supported by a restricting portion upper surface 47 a as an abutting member that is the upper surface of the restricting portion 47.

Further, on both sides in the scanning direction of the restricting portion 47 of the holder main body 43, a plate spring-like lower surface pressing spring 45 is fixed as an elastic member that applies an elastic force upward from the lower surface of the adjusted lens 41, respectively. The lower surface pressing spring 45 comes into contact with the lower surface of the adjusted lens 41 at the lower surface pressing portion 45a and presses the adjusted lens 41 upward.
On the other hand, the top plate 42 is a leaf spring as a central elastic member that applies an elastic force downward from the upper surface of the adjusted lens 41 to a position facing the restriction portion 47 of the holder body 43 via the adjusted lens 41. The upper surface pressing spring 49 is fixed. The upper surface pressing spring 49 comes into contact with the upper surface of the adjusted lens 41 at the upper surface pressing portion 49a and presses the adjusted lens 41 downward.
Further, the adjustment as a pressing member, which will be described in detail later, on both sides in the scanning direction of the upper surface pressing spring 49 of the top plate 42 and at the positions facing the lower surface pressing portions 45a of the two lower surface pressing springs 45 with the adjusted lens 41 interposed therebetween. A screw 44 is provided.

  If a resin member is used as the lens 41 to be adjusted, if the metal adjusting screw 44 is pressed directly, the tip of the adjusting screw 44 is buried in the upper surface of the lens 41 to be adjusted. There is a risk of injury. In contrast, the adjusted lens 41 used in the present embodiment is provided with a glass plate 41b having a hardness higher than that of the resin lens main body 41a as a sliding member on the upper surface of the lens main body 41a, and the tip of the adjusting screw 44 is provided. Is configured to press the upper surface of the glass plate 41b. Thereby, it can prevent that the front-end | tip part of an adjustment screw embeds in the to-be-adjusted lens 41. FIG.

Next, the characteristic part of this embodiment is demonstrated.
FIG. 1 is a schematic view of a lens unit 200 as an optical element unit described with reference to FIGS. 5 and 6 when viewed from the direction of arrow D in FIG. As shown in FIG. 1, the adjusted lens 41 is held on the lens holder 40 by an upper surface pressing spring 49, an adjusting screw 44, a regulating portion upper surface 47 a and a lower surface pressing spring 45.

In the lens holder 40, the restricting portion 47 serves as an abutting member, and the restricting portion upper surface 47a abuts against the center portion of the lens from the lower side in the sub scanning direction. On the other hand, the upper surface pressing spring 49 serves as a central elastic member, toward the regulating unit upper surface 47a side, that is, downward, with respect to a position facing the regulating unit upper surface 47a in the center of the lens across the lens 41 to be adjusted. Then, an elastic force is applied to press the lens 41 to be adjusted. Further, since the upper surface pressing spring 49 is fixed to the top plate 42 and the restricting portion 47 is a part of the holder main body 43, the upper surface pressing spring 49 and the restricting portion 47 are configured to be fixed to the lens holder 40. The lens central portion of the adjusted lens 41 is pressed downward by the upper surface pressing spring 49 and abuts against the restricting portion upper surface 47a of the restricting portion 47, whereby the position of the lens holder 40 in the sub-scanning direction is fixed. In such a lens holder 40, the center portion fixing means is constituted by the upper surface pressing spring 49 and the restricting portion upper surface 47a.
As described above, the position of the lens central portion of the adjusted lens 41 in the sub-scanning direction with respect to the lens holder 40 can be fixed by the upper surface pressing spring 49 and the restricting portion upper surface 47a. For this reason, it is possible to prevent the position where the laser light emitted from the LD unit 70 passes from being shifted with respect to the center position of the adjusted lens 41 in the sub-scanning direction.

On both sides in the scanning direction with respect to the center portion of the lens 41 to be adjusted, there are curvature adjusting portions to which a force is applied in the sub-scanning direction by the adjusting screw 44 and the lower surface pressing spring 45. In other words, a portion that is sandwiched between the adjusting screw 44 of the lens to be adjusted 41 and the lower surface pressing spring 45 is a curvature adjusting portion. In the lens holder 40, the adjusting screw 44 provided on the top plate 42 presses against the curve adjusting portion of the lens 41 to be adjusted from the upper end, which is one of the sub-scanning directions, as a pressing member. On the other hand, the lower surface pressing spring 45 is an elastic member, and an elastic force is applied toward the adjustment screw 44 side, that is, upward, with respect to a position facing the adjustment screw 44 of the bending adjusting unit and the lens 41 to be adjusted. The adjusted lens 41 is pressed by acting.
By rotating the two adjusting screws 44, the position of the tip of the lens holder 40 with respect to the top plate 42 in the sub-scanning direction can be displaced. When the adjustment screw 44 is rotated to adjust the tip of the adjustment screw 44 downward, the bending adjustment portion is pushed downward by the adjustment screw 44 and the lower surface pressing spring 45 is contracted (the lower surface pressing portion 45a is lowered). The bending adjustment portion is displaced downward. On the other hand, when the adjustment screw 44 is rotated and adjusted so that the tip of the adjustment screw 44 is directed upward, the lower surface pressing spring 45 pushes up the curve adjusting portion and the lower surface pressing spring 45 extends (the lower surface pressing portion 45a rises). The bending adjustment unit is displaced upward.

As shown in FIG. 1, the central portion of the adjusted lens 41 is fixed, and the outside of the two curved adjustment portions in the scanning direction of the adjusted lens 41 is a free end. For this reason, when the curvature adjusting unit is positioned below the center of the lens, the lens end that is the scanning direction end of the adjusted lens 41 is also positioned below the center of the lens. Similarly, when the curvature adjusting unit is positioned above the center of the lens, the lens end is also positioned above the center of the lens.
That is, as shown in FIG. 1, the adjusted lens 41 is adjusted from a linear state so that the tip portions of the two adjusting screws 44 are displaced downward, and the lens adjusting portion is also displaced downward by displacing the bending adjusting portion. The lens 41 is displaced downward, and the adjusted lens 41 is in a curved state convex upward. Similarly, the adjustment lens 41 is adjusted so that the tip ends of the two adjustment screws 44 are displaced upward from the linear state, and the lens adjustment portion is also displaced upward by displacing the bending adjustment portion upward. The to-be-adjusted lens 41 is in a downwardly convex curved state. In such a lens holder 40, the bending adjusting means is constituted by the two sets of adjusting screws 44 and the lower surface pressing spring 45. Note that the arrangement of the adjusting screw 44 and the lower surface pressing spring 45 may be closer to the center of the lens than the arrangement shown in FIG.
Thus, the two sets of adjusting screws 44 and the lower surface pressing spring 45 can displace the position of the lens end in both the sub-scanning directions, that is, in the vertical direction with respect to the position of the center of the lens. For this reason, it is possible to adjust the curved state of the adjusted lens 41 so that it is convex in either the upper or lower direction.

  As described with reference to FIG. 1, in the lens unit 200, it is possible to perform adjustment so that the curved state of the adjusted lens 41 is convex in both the upper and lower directions, and the vertical direction of the adjusted lens 41 can be adjusted. It is possible to prevent the position where the laser light emitted from the LD unit 70 passes from being shifted from the center position.

Next, correction of scanning line bending in the lens unit 200 will be described.
Here, it is assumed that the surface movement direction of the photoconductor 10M corresponds to the upper side of the adjusted lens 41M in the sub-scanning direction for the adjusted lens 41M that transmits laser light corresponding to the magenta image. If the scanning lens is bent in such a way that the scanning lens 41M is linear and the scanning line scanned on the photoconductor 10M is convex in the surface movement direction, the two adjusting screws 44M are loosened, Adjustment is made so that the shape of the adjusted lens 41M is convex downward. As a result, the scanning line on the photoconductor 10M can be brought close to a straight line, and the scanning line is corrected by adjusting the adjusting screw 44M so that the scanning line becomes linear.
At this time, in the adjusted lens 41C that transmits laser light corresponding to the cyan image, the surface movement direction of the photoreceptor 10C corresponds to the lower side of the adjusted lens 41C in the sub-scanning direction. This is because the mounting directions of the magenta adjusted lens 41M and the cyan adjusted lens 41C are opposite to each other. Then, in the case where the lens to be adjusted 41C is in a linear state and the scanning line is bent such that the scanning line scanned on the photoconductor 10C is convex in the surface movement direction, the two adjusting screws 44C are tightened. Thus, adjustment is made so that the shape of the adjusted lens 41M is convex upward. As a result, the scanning line on the photoconductor 10C can be brought close to a straight line, and the scanning line is corrected by adjusting the adjusting screw 44C so that the scanning line becomes linear.

  In addition, the lens unit 200 can adjust the pressing amounts of the two adjusting screws 44 against the adjusted lens 41. That is, it is also possible to adjust by moving only the right end or only the left end of the adjusted lens 41 in FIG. 1 up and down. The scanning line curve on the photoconductor 10 may be not only a curve that is convex or convex in the surface movement direction of the photoconductor 10, but may also be a scan line curve in which one end side in the scan line direction is lowered in the surface movement direction. . For such scanning line bending, the scanning line bending is corrected by displacing the lens end of the adjusted lens 41 only on the side corresponding to the end where the scanning line is lowered. be able to.

Next, correction of the scanning line tilt in the lens unit 200 will be described.
The inclination of the scanning line on the photoconductor 10 can be adjusted by adjusting the inclination with the optical axis direction of the adjusted lens 41 in the optical system as the rotation axis. Therefore, by adjusting the inclination of the lens unit 200 with respect to the housing of the optical scanning device 4, the inclination of the adjusted lens 41 in the optical system can be adjusted, and the inclination of the scanning line on the photoconductor 10 can be adjusted. it can.
The restricting portion 47 formed on the holder main body 43 of the lens holder 40 is provided with a unit rotation shaft 48 that serves as a fulcrum for the swinging operation of the lens unit 200 described later in detail. Further, the protruding piece 50 provided on the adjusted lens 41 is pushed between two positioning pins 51 fixed to the housing of the optical scanning device 4, so that the lens 41 of the adjusted lens 41 with respect to the housing of the optical scanning device 4 is pressed. Positioning in the optical axis direction is performed. On the other hand, the unit rotation shaft 48 is positioned in the scanning direction by being fitted into a V-shaped groove 53 a provided in a unit support member 53 as a rotation shaft support member fixed to the housing of the optical scanning device 4. Further, with the unit rotating shaft 48 fitted in the V-shaped groove 53a, a rotating shaft positioning spring 57 is attached and fixed to the housing 400 of the optical scanning device 4 as shown in FIGS. The rotary shaft positioning spring 57 applies an elastic force downward to the unit rotary shaft 48. As a result, the lower side of the unit rotary shaft 48 is positioned by the V-shaped groove 53a, and the upper side of the unit rotary shaft 48 is positioned by the rotary shaft positioning spring 57.

  The housing of the optical scanning device 4 and the lens holder 40 are positioned in the scanning direction by the V-shaped groove 53a and the unit rotation shaft 48, and the scanning direction of the lens 41 to be adjusted and the lens holder 40 by the protrusion 46 and the groove 47b. Therefore, the housing of the optical scanning device 4 and the adjusted lens 41 are positioned in the scanning direction. Thereby, it is possible to realize a configuration in which the optical axis of the laser light L passes through the center of the adjustment lens 41 in the scanning direction.

The optical scanning device 4 includes a stepping motor 54 that swings the lens unit 200 about the unit rotation shaft 48 with respect to the housing 400.
A power transmission piece 56 that receives transmission of power from the stepping motor 54 is provided at one end in the scanning direction of the lens unit 200, and the power from the stepping motor 54 is transmitted to the power transmission piece 56 via the drive gear 55. It has become. Then, by driving the stepping motor 54, the lens unit 200 is swung with the unit rotation shaft 48 as a fulcrum, and the inclination of the lens unit 200 with respect to the optical scanning device 4 is adjusted. Thereby, the inclination of the scanning line on the photoconductor 10 can be adjusted, and the correction of the scanning line inclination can be performed.
The stepping motor 54 is driven by providing an inclination detection means (not shown) that detects an inclination from a toner patch formed on the photosensitive member 10 or the intermediate transfer belt 20, and the position of the scanning line detected by the inclination detection means. The stepping motor 54 is driven in accordance with the inclination corresponding to the deviation amount, and thereby the inclination of the scanning line is corrected.

Like the printer 100 shown in FIG. 2, four photoconductors 10 are arranged in the transport direction of the transfer paper P, and a plurality of scanning optical systems corresponding to the photoconductors 10 are simultaneously exposed to form latent images. Laser images obtained by developing the latent images of the toner images with a developing device 12 using developers of different colors, and then transferring these visible images on the same transfer paper P in sequence and transferring them. Conventional image forming apparatuses such as the above have the following problems. That is, in the four-drum tandem system as shown in FIG. 2, a multi-color image is formed by sequentially superimposing and transferring onto the transfer paper P, so that there is an error in the scanning optical system corresponding to each color. Therefore, when the scan lines have different curvatures, color misregistration occurs between the four colors.
In the configuration described in Japanese Patent Application Laid-Open No. 20004-287380, for an optical element provided in the optical element group, a mechanism for correcting the inclination of the scanning line by changing the inclination of the optical element, and the curvature of the optical element are changed. There is shown an optical scanning device that includes a mechanism that corrects the curvature of the scanning line caused by the change, and that can correct the bending and inclination of the scanning line. However, in this optical scanning device, three sets (in the center and both sides) of pressing mechanisms constituting the scanning line bending correction mechanism are required in the scanning direction, resulting in a complicated configuration.

On the other hand, in the lens unit 200 of the printer 100 according to the present embodiment, as a scanning line bending correction mechanism, the lens central portion of the adjusted lens 41 is fixed to the lens unit 200 and is positioned on both sides of the lens central portion in the scanning direction. Two sets of adjusting screws 44 and a lower surface pressing spring 45 are provided. With such a lens unit 200, the adjusted lens 41, which is an optical element, can be accurately aligned with the lens holder 40, and a practical configuration in which the configuration of the scanning line bending correction mechanism is simplified. Can be realized.
In addition, even if the scanning line curvature of each color is different in the four-drum tandem system as shown in FIG. 2, by adjusting the scanning line bending of each color, the direction of the curved state is aligned so that the color misregistration between the four colors is achieved. It can be kept small.

Like the lens unit 200, if the lens to be adjusted 41 and the lens holder 40 are long members whose scanning direction of laser light is the longitudinal direction, the scanning direction by thermal expansion of the lens to be adjusted 41 and the lens holder 40. The amount of change may vary. If the amount of change in the scanning direction is different, the position of the curvature adjusting unit in the adjusted lens 41 changes.
For example, when the temperature of the installation environment becomes high and the change amount of the metal lens holder 40 is larger than that of the resin-adjusted lens 41, the attachment position of the adjustment screw 44 with respect to the center portion of the lens holder 40 is scanned. Move out of direction. As a result, the curvature adjusting portion of the adjusted lens 41 is also moved outward in the scanning direction. At this time, since the adjustment screw 44 as a pressing member is in a state of pressing the lens 41 to be adjusted, if the frictional force between the tip of the adjustment screw 44 and the upper surface of the lens 41 to be adjusted is large, the tip of the adjustment screw 44 is There is a possibility that the adjusted lens 41 may be damaged by scraping the upper surface of the adjusted lens 41 during the movement of the curvature adjusting unit. Further, if the frictional force is so large that the tip of the adjustment screw 44 cannot move in the scanning direction with respect to the upper surface of the adjusted lens 41, the bending state of the adjusted lens 41 changes or the lens holder 40 is bent. There is a risk of doing so.

For such a problem, the adjusted lens 41 of the lens unit 200 provided in the optical scanning device 4 of the printer 100 is a glass as a sliding member that prompts the adjustment screw 44 to slide on the upper surface of the resin lens body 41a. A plate 41b is provided. By providing the glass plate 41b to urge the sliding on the upper surface of the lens body 41a, the tip portion of the adjustment screw 44 is easily ing movement in the scanning direction with respect to the adjusting lens 41. This prevents damage to the adjusted lens 41, changes in the curved state of the adjusted lens 41, bending of the lens holder 40, etc. due to a large frictional force between the tip of the adjusting screw 44 and the adjusted lens 41. Can do. If the tip of the metal adjustment screw 44 is buried in the lens 41 to be adjusted, the position of the tip of the adjustment screw 44 relative to the lens 41 to be adjusted can be displaced. The same problem as when the frictional force with the adjusted lens 41 is too large can occur. The adjusted lens 41 of the lens unit 200 is provided with a glass plate 41b having a hardness higher than that of the resin lens body 41a on the upper surface of the lens body 41a. As a result, the tip of the adjustment screw 44 is prevented from being embedded in the lens 41 to be adjusted, the damage of the lens 41 to be adjusted caused by the tip of the adjustment screw 44 being embedded in the lens 41 to be adjusted, and the lens to be adjusted. 41 can be prevented from changing, the lens holder 40 from being bent, and the like.

  Further, the difference in the amount of change in the scanning direction due to thermal expansion can occur not only between the lens holder 40 and the adjusted lens 41 but also between the holder main body 43 and the top plate 42 constituting the lens holder 40. If the amount of change in the scanning direction due to thermal expansion differs between the holder body 43 and the top plate 42 that fix both ends at the both ends in the scanning direction, the amount of change between the holder body 43 and the top plate 42 is large. There is a risk that the direction will be curved. This occurs because the distance between the end portions of the holder body 43 in the scanning direction is different from the distance between the end portions of the top plate 42 in the scanning direction. For such a problem, the lens holder 40 of the lens unit 200 has a through-hole through which the fixing screw 42a that fixes both ends of the holder main body 43 and the top plate 42 penetrates the top plate 42. In contrast to the round hole 42b, the back side in FIG. 6 is a long hole 42c whose scanning direction is the longitudinal direction. Thereby, the end of the top plate 42 on the side of the round hole 42b is fixed in the scanning direction with respect to the fixing portion 43b of the end of the holder body 43, but the end of the top plate 42 on the side of the elongated hole 42c is fixed to the holder body. With respect to the fixing portion 43c at the end of 43, the scanning direction can be shifted within the longitudinal direction of the long hole. As described above, one of the fixing portions of the top plate 42 and the holder main body 43 can be shifted in the longitudinal direction, so that the larger the amount of change due to thermal expansion between the holder main body 43 and the top plate 42 is curved. Can be prevented.

In the lens unit 200, the configuration in which the glass plate 41 b is provided on the upper surface of the lens body 41 a as the sliding member provided between the tip of the adjustment screw 44 and the adjusted lens 41 has been described. The sliding member provided between the tip of the adjusting screw 44 and the lens to be adjusted 41 is not limited to the glass plate 41b, but may be a sliding roller 44a as shown in FIG.
Hereinafter, a configuration in which the sliding member is the sliding roller 44a will be described with reference to FIG. In the lens unit 200 shown in FIG. 9, a sliding roller 44a is fixed to the tip of the adjusting screw 44, and the sliding roller 44a can rotate around a rotation axis parallel to the optical axis direction which is the front-back direction in the figure. It has become.
With such a configuration, it is possible to prevent the tip of the adjustment screw 44 from being buried in the adjusted lens 41 and damaging the adjusted lens 41 as in the case where the sliding member is the glass plate 41b. Further, the sliding of the upper surface of the adjusted lens 41 with respect to the adjusting screw 44 can be promoted.

  In the lens unit 200 described with reference to FIGS. 5, 6, etc., the opening 42 d is provided at the center of the top plate 42, and the upper surface pressing spring 49 is fixed to the upper surface of the top plate 42 by the upper surface spring fixing screw 49 b. The upper surface pressing portion 49a passes through the opening 42d and comes into contact with the upper surface of the adjusted lens 41. As shown in FIG. 10, the upper surface pressing spring 49 may be configured to be fixed to the lower surface of the top plate 42 by an upper surface spring fixing screw 49b. With the configuration of FIG. 10, it is not necessary to provide the opening 42 d in the top plate 42.

  In the present embodiment, the case where the optical element is the adjustable lens 41 as a long lens has been described, but the optical element is not limited to a long lens. For example, even in the case of a long concave mirror, the bending state of the scanning line on the photosensitive member scanned by the optical scanning device having the optical system including the concave mirror can be adjusted by adjusting the bending state in the longitudinal direction. it can. Therefore, the characteristic part of this embodiment is applicable even if an optical element is a concave mirror.

As described above, according to the present embodiment, the lens to be adjusted is provided in the direction corresponding to the sub-scanning direction of the lens 41 to be adjusted, which is an optical element, by including the upper surface pressing spring 49 and the restricting portion upper surface 47a as the central portion fixing means. The position of the lens center portion 41 with respect to the lens holder 40 which is a holding member can be fixed. Further, by providing two sets of adjusting screws 44 and a lower surface pressing spring 45 as a bending adjusting means, the position of the lens end portion which is the scanning direction end portion of the adjusted lens 41 in the vertical direction with respect to the lens central portion is adjusted. Thus, it is possible to adjust the curved state of the adjusted lens 41, and the two sets of adjusting screws 44 and the lower surface pressing spring 45 move the position of the lens end portion up and down relative to the position of the lens central portion of the adjusted lens 41. It can be displaced in both directions. For this reason, by fixing the position in the direction corresponding to the sub-scanning direction with respect to the lens holder 40 in the center of the lens 41 to be adjusted, the position of the center of the lens 41 to be adjusted in the direction corresponding to the sub-scanning direction is fixed. Thus, it is possible to prevent the position where the laser light emitted from the LD unit 70 passes from shifting. Further, the position of the lens end portion can be displaced in both directions in the direction corresponding to the sub-scanning direction with respect to the position of the center of the lens, that is, in the vertical direction, so that the curved state of the adjusted lens 41 can be changed in the vertical direction. It is also possible to make the adjustment to be convex. This prevents the scanning line irradiated on the surface of the photoconductor 10 from being distorted due to the shift of the position where the laser beam passes with respect to the center position of the adjusted lens 41 in the direction corresponding to the sub-scanning direction, In addition, it is possible to correct both the scanning line curvature convex in the surface moving direction of the photoconductor 10 and the scanning line curvature convex in the opposite direction.
Further, there are curvature adjusting portions on both sides in the scanning direction with respect to the center portion of the lens 41 to be adjusted, and two sets of adjusting screws 44 as pressing members and lower surface pressing springs 45 as elastic members are provided as bending adjusting means, By adjusting the pressing amount of the adjusting screw 44, the bending state of the adjusted lens 41 can be adjusted by displacing the position of the bending adjusting unit in the direction corresponding to the sub-scanning direction.
Further, by rotating as a pressing member, the position of the tip portion in the direction corresponding to the sub-scanning direction with respect to the lens holder 40 can be displaced, and the tip portion is adjusted to press the curve adjusting portion of the lens 41 to be adjusted. By using the screw 44, the bending adjusting means can be realized with a simple configuration.
Further, by providing a glass plate 41b that is a sliding member between the tip of the adjusting screw 44 and the lens body 41a that is an optical element, damage to the adjusted lens 41 and changes in the curved state of the adjusted lens 41, The bending of the lens holder 40 can be prevented.
Further, by providing the central portion positioning means with the protrusion 46 of the adjusted lens 41 and the regulating portion 47 having the groove 47b, the optical axis of the laser light L passes through the center of the adjusted lens 41 in the scanning direction. It is possible to realize a configuration to
Further, as a central portion fixing means, a regulating portion 47 that is a butting member and an upper surface pressing spring 49 that is a central elastic member are provided, and the regulating portion 47 and the upper surface pressing spring 49 are fixed to the lens holder 40. Thus, it is possible to realize a configuration in which the position in the direction corresponding to the sub-scanning direction with respect to the lens holder 40 at the center of the lens 41 to be adjusted is fixed.
Further, by adjusting the curved state of the adjusted lens 41, which is a long lens whose scanning direction of the transmitted laser light is the longitudinal direction, the scanning line bending on the surface of the photoreceptor 10 of the transmitted irradiation light is corrected. be able to.
Further, in the case of the optical scanning device 4 including the lens unit 200, the scanning line irradiated on the surface of the photoconductor 10 is prevented from being distorted, and the scanning line curve that is convex in the surface moving direction of the photoconductor 10 is also reversed. It is possible to realize an optical scanning device capable of correcting a scanning line curve that is convex in the direction.
In addition, the inclination of the scanning direction of the lens unit 200 with respect to the housing 400 of the optical scanning device 4 can be adjusted, whereby the inclination of the scanning line on the surface of the photoconductor 10 can be corrected.
Further, since the unit rotation shaft 48 is fixed to the lens holder 40, the lens holder 40 can be positioned with respect to the housing 400 by positioning the unit rotation shaft 48 with respect to the housing 400.
Further, since the unit rotation shaft 48 is positioned with respect to the unit support member 53 that is a rotation shaft support member fixed to the housing 400, it is possible to realize a configuration in which the lens holder 40 is positioned with respect to the housing 400. it can.
Further, in the case of the printer 100 as an image forming apparatus provided with the optical scanning device 4, the scanning lines on the photoconductor 10 can be prevented from being distorted, and the scanning line bending can be corrected, so that good image formation is performed. be able to. Furthermore, even if the scanning line curvature of each color is different in the 4-drum tandem system as shown in FIG. It can be kept small.

The front schematic diagram of the lens unit of this embodiment. 1 is a schematic configuration diagram of a printer according to an embodiment. 1 is a schematic configuration diagram of an image forming station. FIG. FIG. The perspective exploded explanatory drawing of a lens unit. FIG. 6 is a perspective explanatory view of a lens unit to which a rotary shaft positioning spring is attached. The front schematic diagram of the lens unit which attached the rotating shaft positioning spring. The front schematic diagram of the lens unit whose sliding member is a sliding roller. FIG. 3 is an exploded perspective view of a lens unit that fixes an upper surface pressing spring to the lower surface of the top plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Paper feed cassette 3 Image forming station 4 Optical scanning device 5 Intermediate transfer unit 6 Fixing unit 7 Toner bottle 8 Paper discharge tray 10 Photoconductor 11 Charging device 12 Developing device 40 Lens holder 41 Adjustable lens 42 Top plate 42a Fixed Screw 42b Round hole 42c Elongated hole 42d Opening 43 Holder body 44 Adjustment screw 44a Sliding roller 45 Lower surface pressing spring 45a Lower surface pressing portion 46 Projection portion 47 Restricting portion 47a Restricting portion upper surface 47b Groove portion 48 Unit rotating shaft 49 Upper surface pressing spring 49a Upper surface Pressing part 49b Upper surface spring fixing screw 50 Projection piece 51 Positioning pin 53 Unit support member 54 Stepping motor 55 Drive gear 56 Power transmission piece 57 Rotating shaft positioning spring 80 Polygon mirror 100 Printer 200 Lens unit 400 Housing

Claims (10)

An optical element that forms an image of the deflected and scanned irradiation light on the surface to be scanned;
A holding member for holding the optical element;
In the optical element unit and a regulation to that bay song adjusting means a curved state of the optical element in the direction corresponding to the sub-scanning direction on the surface to be scanned,
A central portion fixing means for fixing a position in a direction corresponding to the sub-scanning direction with respect to the holding member at the central portion in the scanning direction of the optical element;
On both sides of the scanning direction with respect to the central portion in the scanning direction of the optical element, there is a curvature adjusting unit that applies a force in a direction corresponding to the sub-scanning direction,
The bending adjusting means is a pressure whose position in the scanning direction with respect to the holding member is fixed, presses the bending adjusting portion of the optical element from one of the directions corresponding to the sub-scanning direction, and can adjust the pressing amount. A member, and an elastic member that opposes the pressing member and the optical element so as to oppose the bending amount adjustment portion of the optical element toward the pressing member, and
By adjusting the pressing amount of the pressing member, the position in the direction corresponding to the sub-scanning direction of the curvature adjusting unit with respect to the position of the central portion in the scanning direction of the optical element is displaced , Adjusting the curved state of the optical element by displacing the position in both directions in the direction corresponding to the sub-scanning direction with respect to the position of the central part in the scanning direction of the optical element ;
The optical element and the holding member differ in the amount of change in the scanning direction due to thermal expansion,
An optical element unit, wherein a sliding member that facilitates sliding between the pressing member and the optical element is provided between the pressing member and the optical element . In the optical element unit 請 Motomeko 1,
The pressing member is an adjusting screw, and by rotating the adjusting screw, the position of the tip portion in a direction corresponding to the sub-scanning direction with respect to the holding member is displaced, and the tip of the adjusting element is used to displace the tip of the optical element. An optical element unit that presses the bending adjustment unit. In the optical element unit according to claim 1 or 2,
An optical element unit comprising: a center part positioning means for positioning in the scanning direction between the center part in the scanning direction of the holding member and the center part in the scanning direction of the optical element. In the optical element unit according to claim 1, 2 or 3,
The center fixing means includes an abutting member that abuts from one of the directions corresponding to the sub-scanning direction with respect to the central portion of the optical element in the scanning direction, and the abutting member that faces the optical element across the optical element. A central elastic member for applying an elastic force to the abutting member side with respect to the central portion of the element, and the abutting member and the central elastic member are fixed to the holding member. Optical element unit. According to claim 1, 2, 3 or 4 of the optical element unit,
The optical element unit is a long lens in which a scanning direction of incident irradiation light is a longitudinal direction. A light source;
Light deflecting means for deflecting and scanning the irradiation light from the light source;
In an optical scanning device having an optical system that forms an image of the irradiation light from the light deflecting unit on the surface to be scanned,
Optical system according to claim 1, 2, 3, an optical scanning device which comprises an optical element unit 4 or 5. The optical scanning device according to claim 6 .
The optical element unit is swingable with respect to the housing of the optical scanning device about a unit rotation axis whose axial direction is a direction orthogonal to the scanning direction and the direction corresponding to the sub-scanning direction. An optical scanning device capable of adjusting an inclination of the optical element unit with respect to the casing with respect to the center. The optical scanning device according to claim 7 .
The unit rotation axis is an optical scanning apparatus characterized by being et provided integrally with the holding member of the optical element unit. The optical scanning device according to claim 8 .
The optical scanning device according to claim 1, wherein the unit rotation shaft is positioned with respect to a rotation shaft support member fixed to the housing. By irradiating the surface of the latent image carrier with scanning light using an optical scanning unit, a latent image is formed on the surface of the latent image carrier, and an image obtained by developing the latent image is finally recorded. In an image forming apparatus that forms an image by transferring it onto a material,
An image forming apparatus using the optical scanning device according to claim 6, 7, 8, or 9 as the optical scanning unit.

Images