JP2013148658A - Scanning optical apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanning optical apparatus in which stress applied to a scanning optical element is suppressed, and accuracy of positioning of the scanning optical element with respect to a holder is excellent.SOLUTION: The scanning optical apparatus includes: a long scanning optical element 10 for forming, on a photoreceptor, an image of light emitted from a light source; a holder 50 to which the scanning optical element 10 is attached; a shaft-shaped member 81 provided in the holder 50; and a hole 16 provided in the scanning optical element 10. An inner diameter of the hole 16 is larger than an outer diameter of the shaft-shaped member 81, and the scanning optical element 10 is positioned with respect to the holder 50, by enlarging the diameter of the shaft-shaped member 81 after inserting the shaft-shaped member 81 into the hole 16.

Description

  The present invention relates to a scanning optical device.

  In recent years, the required performance for scanning optical devices has been increasing, and the mounting accuracy of optical elements incorporated therein has also been increasing. However, the scanning optical element (scanning optical element) is long, easily deformed when fixed, and difficult to handle.

  For this reason, there is a need for stress-free mounting of the scanning optical element to the holder, and further, it is required to suppress the looseness at the time of mounting. For example, a pin protruding from the holder is press-fitted into a hole formed in the optical element. Proposed (see Patent Document 1), or a structure in which the fitting backlash when the optical element is inserted into the holder is modified by partially deforming the outer periphery of the insertion hole (see Patent Document 2). ing.

JP-A-4-253010 JP 2003-98464 A

  However, in the configuration described in Patent Document 1, since the hole and the pin have a press-fitting tolerance, the optical element may be deformed by the stress when performing the press-fitting, and it is inserted to the end. There is a possibility that the optical element is slightly lifted and cannot be attached at a proper position.

  On the other hand, in the configuration described in Patent Document 2, since the amount of fitting play is reduced, there is a problem that the center position of the optical element is shifted by the amount of play and optical performance is deteriorated.

  The present invention has been made in order to solve the problems associated with the prior art described above, and the stress applied to the scanning optical element is suppressed, and the scanning optical element positioning accuracy with respect to the holder is good. An object is to provide an optical device.

  The above object of the present invention is achieved by the following means.

(1) a long scanning optical element for forming an image of light output from a light source on a photosensitive member;
A holder to which the scanning optical element is attached;
A shaft-like member provided in the holder;
A hole provided in the scanning optical element,
The inner diameter of the hole is larger than the outer diameter of the shaft-shaped member,
The scanning optical device is positioned with respect to the holder by expanding the diameter of the shaft-shaped member after the shaft-shaped member is inserted into the hole.

(2) The shaft-shaped member has a hole portion disposed on the end surface of the tip portion, and a press-fitting member press-fitted into the hole portion,
The outer diameter of the press-fitting member is smaller than the inner diameter of the hole portion of the scanning optical element and larger than the inner diameter of the hole portion of the shaft-shaped member,
The scanning optical device according to (1), wherein the diameter of the shaft-shaped member is increased by press-fitting the press-fitting member into the hole.

  (3) The scanning optical device according to (2), wherein the press-fitting member is spherical or truncated cone.

  (4) The scanning optical system according to (3), wherein the shaft-shaped member has a slit that is located on an outer periphery of the hole portion of the shaft-shaped member and extends in a depth direction of the hole portion. apparatus.

  (5) The scanning optical device according to (4), wherein a plurality of the slits are provided.

  (6) The scanning optical device according to (5), wherein four slits are arranged at equal intervals along the outer periphery of the hole.

  (7) The slit is positioned so as to form an angle of 45 degrees with respect to a main scanning direction and a sub-scanning direction for forming an image of light output from the light source on a photosensitive member. The scanning optical device according to (6) above.

  (8) The scanning optical device according to (5), wherein the shaft-shaped member is rotatably arranged and has directionality in the diameter expansion.

  (9) The scanning optical device according to (8), wherein the directionality of the diameter expansion is set by changing a width of the slit and / or an interval of the slit.

(10) The hole portion of the shaft-shaped member has a female screw portion extending from the bottom surface of the hole portion,
The press-fitting member has a male screw part that can be screwed with the female screw part, a connector part that can be engaged with a screwdriver, and an extension part that connects the male screw part and the connector part,
The scanning optical device according to any one of (2) to (9), wherein an outer diameter of the extension portion is larger than an inner diameter of the hole portion of the shaft-shaped member.

  (11) The scanning optical device according to any one of (1) to (10), wherein the photoconductor is a photoconductor drum of an image forming apparatus.

  According to the present invention, since the inner diameter of the hole of the scanning optical element is larger than the outer diameter of the shaft-shaped member of the holder, when inserting the shaft-shaped member into the hole and attaching the scanning optical element to the holder, it becomes a clearance fit, Does not generate stress. Therefore, the deformation of the scanning optical element and the occurrence of mounting problems are suppressed. Further, after the shaft-shaped member is inserted into the hole, the diameter of the shaft-shaped member is expanded, so that the gap between the shaft-shaped member and the hole disappears (the shaft-shaped member is thickened more than the fitting backlash). This makes it possible to position the scanning optical element with respect to the holder with high accuracy. For example, since the fitting play (gap) disappears, the position variation of the scanning optical element due to changes in the atmospheric environment may occur. It is suppressed and environmental stability is improved. Therefore, it is possible to provide a scanning optical device in which stress applied to the scanning optical element is suppressed and positioning accuracy of the scanning optical element with respect to the holder is good.

1 is a cross-sectional view for explaining an image forming apparatus according to an embodiment of the present invention. It is a top view for demonstrating the scanning optical apparatus shown by FIG. It is a perspective view for demonstrating the optical element holder shown by FIG. 2, and the end is shown. It is a perspective view for demonstrating the optical element holder shown by FIG. 2, and has shown the other end. It is sectional drawing for demonstrating the X direction press part shown by FIG. It is sectional drawing for demonstrating the Z direction press part shown by FIG. It is sectional drawing for demonstrating the positioning part shown by FIG. It is an enlarged view of the positioning part shown by FIG. It is sectional drawing for demonstrating the modification 1 which concerns on embodiment of this invention. It is sectional drawing for demonstrating the modification 2 which concerns on embodiment of this invention. It is a perspective view for demonstrating the modification 3 which concerns on embodiment of this invention. It is a top view for demonstrating the modification 3 which concerns on embodiment of this invention. It is a top view for demonstrating the modification 4 which concerns on embodiment of this invention. It is a perspective view for demonstrating the modification 5 which concerns on embodiment of this invention. It is sectional drawing for demonstrating the modification 5 which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view for explaining an image forming apparatus according to an embodiment of the present invention.

  An image forming apparatus 100 shown in FIG. 1 is a tandem type color copier, and includes a control unit 110, an image reading unit 120, an operation display unit 130, an image forming unit 140, a transfer unit 150, a fixing unit 155, and a paper transport unit. 160.

  The control unit 110 is a control circuit configured by a microprocessor or the like that executes control of the above-described units and various arithmetic processes according to a program, and each function of the image forming apparatus 100 has a program corresponding to the control unit 110. It is demonstrated by executing.

  The image reading unit 120 is used to generate document image data, and includes a light source 122, an optical system 124, and an image sensor 126. The light source 122 irradiates light on the document placed on the reading surface 128, and the reflected light is imaged on the image sensor 126 that has moved to the reading position via the optical system 124. The image sensor 126 is composed of, for example, a line image sensor, and generates an electric signal (photoelectrically converts) in accordance with the reflected light intensity. The generated electrical signal is input to the image forming unit 140 after image processing. Image processing includes A / D conversion, shading correction, filter processing, image compression processing, and the like.

  The operation display unit 130 includes, for example, an LCD (Liquid Crystal Display) and a keyboard, and is used to present a device configuration, a print job progress status, an error occurrence status, a currently changeable setting, and the like to the user. Output means and input means used for the user to perform various instructions (inputs) such as character input, various settings, and start instructions. The keyboard has a plurality of keys including a selection key for specifying the size of the paper P, a numeric keypad for setting the number of copies, a start key for instructing start of operation, a stop key for instructing stop of operation, and the like.

  The image forming unit 140 uses an electrophotographic process that uses toner, and is used to form an image on a paper P that is a recording medium. The image forming unit 140 forms an image of yellow (Y) color, magenta ( M) an image forming unit 140B that forms an image of color, an image forming unit 140C that forms an image of cyan (C), and an image forming unit 140D that forms an image of black (K).

  Each unit of the image forming unit 140 includes a photosensitive drum 142, a charging unit 143, an optical writing unit 145, a developing device 146, and a cleaning unit 148.

  The photosensitive drum 142 includes a photosensitive layer made of a resin such as polycarbonate including an organic photoconductor (OPC), and is configured to rotate at a predetermined speed. The charging unit 143 includes a corona discharge electrode arranged around the photosensitive drum 142, and charges the surface of the photosensitive drum 142 with the generated ions.

  The optical writing unit 145 incorporates a scanning optical device 170 and exposes the charged photosensitive drum 142 based on the image data input from the image reading unit 120, thereby exposing the exposed portion. The electric potential is lowered to form a charge pattern (electrostatic latent image) corresponding to the image data.

  The developing device 146 develops the formed electrostatic latent image and visualizes it with toner. That is, it is possible to form monochrome images of toners corresponding to yellow, magenta, cyan and black on the photosensitive drums 142 of the image forming units 140A, 140B, 140C and 140D, respectively.

  The cleaning unit 148 scrapes (removes) the residue such as toner and external additives remaining on the surface of the photosensitive drum 142 after the monochrome image is transferred to the intermediate transfer belt 151 described later, thereby removing the surface. Used to maintain good condition.

  The transfer unit 150 includes an intermediate transfer belt 151, a primary transfer unit 153, and a secondary transfer unit 154. The intermediate transfer belt 151 is wound around a primary transfer unit 153 and a plurality of rollers, and is supported so as to be able to run. The primary transfer unit 153 includes primary transfer modules 153A, 153B, 153C, and 153D corresponding to yellow, magenta, cyan, and black. The secondary transfer unit 154 is disposed outside the intermediate transfer belt 151 and is positioned so that the paper P can pass between the secondary transfer unit 154 and the intermediate transfer belt 151.

  The monochrome images of the respective colors formed in the image forming units 140A to 140D are sequentially transferred onto the intermediate transfer belt 151 by the primary transfer modules 153A to 153D, and the yellow, magenta, cyan, and black layers are superimposed. A color image is formed. The formed color image is transferred to the conveyed paper P by the secondary transfer unit 154.

  The fixing unit 155 is used for fixing the color image transferred to the paper P, and includes a heating roller 157 and a pressure roller 158. When the paper P passes between the heating roller 157 and the pressure roller 158, pressure and heat are applied to melt the toner, thereby fixing the color image.

  The paper transport unit 160 includes a paper feed unit 162, a registration roller 164, a fixing transport roller 165, a paper discharge roller 166, and a paper reversing unit 168.

  The paper feed unit 162 includes paper feed trays 162A to 162C that store paper P, a feed roller 163A, and a separation roller 163B. The feed roller 163A and the separation roller 163B feed sheets one by one from the sheet feed trays 162A to 162C to the transport path.

  The registration roller 164 conveys the paper P fed from the paper feeding unit 162 to the secondary transfer unit 154. The fixing conveyance roller 165 conveys the paper P that has passed through the secondary transfer unit 154 and the fixing unit 155 toward the paper discharge roller 166. The paper discharge roller 166 discharges the conveyed paper P to the outside of the apparatus.

  The paper reversing unit 168 introduces the paper P that has passed through the fixing conveyance roller 165 into a conveyance path between the paper feed trays 162 </ b> A to 162 </ b> C and the paper discharge roller 166 instead of a conveyance path toward the paper discharge roller 166. The sheet P is used to turn the paper P upside down and discharge it, or to form images on both sides of the paper P.

  Next, the scanning optical device 170 incorporated in the optical writing unit 145 will be described in detail.

  FIG. 2 is a plan view for explaining the scanning optical device shown in FIG.

  The scanning optical device 170 includes a light source 172, a light source holder 174, optical systems 176 and 178, a deflector 180, scanning optical elements 10 and 10A, optical element holders 50 and 50A, a condensing lens 182 and a beam detection sensor 184. These are accommodated in a housing 186 made of a box-shaped frame. In the scanning optical device 170, as will be described later, the stress applied to the scanning optical elements 10, 10A is suppressed, and the positioning accuracy of the scanning optical elements 10, 10A with respect to the optical element holders 50, 50A is good. is there.

  The light source 172 is made of a semiconductor laser and is held by a light source holder 174 fixed to the housing 186. The optical system 176 has a collimator lens and converts the light emitted from the semiconductor laser into parallel light. The optical system 178 has a cylindrical lens and collects parallel light in the sub-scanning direction (converts it into convergent light). The deflector 180 includes a polygon mirror unit, and deflects the convergent light in the main scanning direction Y at an equal angular velocity. The main scanning direction Y and the sub scanning direction Z are orthogonal to each other.

  The scanning optical elements 10 and 10A are held (attached) by optical element holders 50 and 50A fixed to the housing 186. The scanning optical elements 10 and 10A are elongated and extend in the main scanning direction Y. The light is condensed on the photosensitive drum 142, and the photosensitive drum 142 is scanned and exposed in the main scanning direction M. That is, the scanning optical elements 10 and 10 </ b> A are used to form an image of the light beam output from the light source 172 on the photosensitive drum 142.

  The condenser lens 182 and the beam detection sensor 184 are used for adjusting the timing of the image writing position. The condensing lens 182 condenses the light transmitted through the scanning optical element 10 toward the beam detection sensor 184, and the beam detection sensor 184 detects the beam transmitted through the condensing lens 182. The beam detection sensor 184 includes, for example, a photoelectric conversion element, and the detection signal is input to a control circuit (not shown) in order to generate a synchronization signal.

  Next, the optical element holder 50 and the scanning optical element 10 will be described in detail. The optical element holder 50A and the scanning optical element 10A have substantially the same configuration as that of the optical element holder 50 and the scanning optical element 10, and therefore the description thereof is omitted to avoid duplication.

  3 and 4 are perspective views for explaining the optical element holder shown in FIG. 2, showing one end and the other end thereof, respectively, and FIG. 5 shows the X direction pressing portion shown in FIG. FIG. 6 is a cross-sectional view for explaining the Z-direction pressing portion shown in FIG. 3, FIG. 7 is a cross-sectional view for explaining the positioning portion shown in FIG. 3, and FIG. FIG. 7 is an enlarged view of the positioning portion shown in FIG. 6.

  The optical element holder 50 is configured such that the scanning optical element 10 is inserted from the X direction, and an X direction pressing portion 60 and a Z direction pressing portion 70 disposed at both ends, and a positioning portion 80 disposed at the center portion. And having. The X direction pressing unit 60 is used to press the scanning optical element 10 in the X direction. The Z direction pressing part 70 is used for pressing the scanning optical element 10 in the Z direction (sub-scanning direction). The positioning unit 80 is used for positioning the scanning optical element 10 in the X direction, Y direction (main scanning direction), and Z direction.

  The scanning optical element 10 has a protruding portion 12, a semi-cylindrical portion 14, and a hole portion 16. The protruding portion 12 has a curved surface shape (so-called SR shape) that constitutes a part of a virtual spherical surface (see FIG. 5), protrudes in the X direction, and is formed so as to cooperate with the X direction pressing portion 60. Has been. The semi-cylindrical portion 14 extends in the X direction (see FIG. 6) and is formed so as to cooperate with the Z direction pressing portion 70. The hole 16 extends in the X direction (see FIG. 7) and is formed so as to cooperate with the positioning unit 80.

  As shown in FIG. 5, the X direction pressing portion 60 of the optical element holder 50 includes a receiving surface 61, a sphere 62, a leaf spring 63, a holding member 64, and a fastening member 67. The receiving surface 61 is formed so as to contact the protruding portion 12 of the scanning optical element 10. The spherical body 62 is disposed on the opposite side of the protruding portion 12 of the scanning optical element 10.

  The holding member 64 has cylindrical holes 65 and 66 extending (penetrating) in the X direction, and is fixed to the optical element holder 50. In the hole 65, the sphere 62 is inserted, and the movement of the sphere 62 is regulated (the sphere 62 is positioned). The fastening member 67 has a shaft portion and an enlarged hemispherical head portion. The shaft portion is inserted into the hole 66. The head portion fastens (fixes) one end of the leaf spring 63 (the end distal from the sphere 62).

  Therefore, since the sphere 62 is positioned on the opposite side of the protruding portion 12 of the scanning optical element 10 and the hole 65 into which the sphere 62 is inserted extends in the X direction, the sphere 62 is pressed by the leaf spring 63. The spherical body 62 presses the scanning optical element 10 in the X direction. That is, the X-direction pressing portion 60 can press (bias) the scanning optical element 10 in the vertical direction with respect to the receiving surface 61, and the scanning optical element 10 is elastically positioned in the X direction. .

  As shown in FIG. 6, the Z-direction pressing portion 70 of the optical element holder 50 includes a cylindrical member 71, a stepped portion 72, a sphere 73, a pressing member 74, a hole 77, and a leaf spring 78.

  The cylindrical member 71 extends in the Y direction along the side surface of the scanning optical element 10 and is in contact with the semicylindrical portion 14 of the scanning optical element 10 in a state orthogonal (rotated by 90 degrees). The stepped portion 72 is formed on the inner wall of the optical element holder 50, and supports the cylindrical member 71 in cooperation with the side surfaces of the scanning optical element 10 facing each other.

  The spherical body 73 is disposed so as to contact the side surface of the scanning optical element 10 distal to the cylindrical member 71 in the Z direction. The pressing member 74 is hemispherical and has a flat surface portion 75 and a spherical portion 76. The flat portion 75 is in contact with the sphere 73. The hole 77 extends in the Z direction, and the sphere 73 and the pressing member 74 are inserted therein. The leaf spring 76 presses the spherical portion 76 of the pressing member 74. Therefore, the pressing member 74 can press (bias) the scanning optical element 10 in the Z direction via the sphere 73, and the scanning optical element 10 is elastically positioned in the Z direction.

  As shown in FIGS. 7 and 8, the positioning portion 80 of the optical element holder 50 includes a shaft-like member 81 and a press-fitting member 90. The shaft-like member 81 is inserted into the hole 16 extending in the X direction in the scanning optical element 10. The inner diameter of the hole 16 of the scanning optical element 10 is larger than the outer diameter of the shaft-shaped member 81, and the scanning optical element 10 is formed by expanding the diameter of the shaft-shaped member 81 after inserting the shaft-shaped member 81 into the hole 16. The optical element holder 50 is positioned.

  In other words, since the inner diameter of the hole 16 of the scanning optical element 10 is larger than the outer diameter of the shaft-shaped member 81, when the shaft-shaped member 81 is inserted into the hole 16 and the scanning optical element 10 is attached to the optical element holder 50, there is a clearance. Fits and does not cause stress. Therefore, the deformation of the scanning optical element 10 and the occurrence of mounting problems are suppressed. Further, after the shaft-shaped member 81 is inserted into the hole portion 16, the diameter S of the shaft-shaped member 81 is increased, so that the gap S between the shaft-shaped member 81 and the hole portion 16 disappears (more than the fitting backlash). Because the backlash is absorbed by thickening the shaft-like member), positioning with respect to the optical element holder 50 can be performed with high accuracy. For example, the fitting backlash (gap) disappears, so that the scanning optics due to changes in the atmospheric environment Variation in the position of the element is suppressed, and environmental stability is improved.

  In the present embodiment, the shaft-like member 81 has a counterbore (hole) 82 formed on the end surface of the tip, and the outer diameter of the press-fitting member 90 is larger than the inner diameter of the hole 16 of the scanning optical element 10. It is smaller and larger than the inner diameter of the counterbore part 82. Therefore, the shaft-shaped member 81 is expanded in diameter by press-fitting the press-fitting member 90 into the counterbore part 82. For example, the outer diameter of the press-fit member 90 is 1.59 mm, the outer diameter of the shaft-shaped member 81 is 1.99 mm, the inner diameter of the counterbore part 82 is 1.54 mm (50 μm smaller than the outer diameter of the press-fit member 90), The distance D between the position (contact position) C at which the press-fitting member 90 and the counterbore part 82 are in contact with the bottom surface of the counterbore part 82 is 0.7 mm.

  In other words, when the press-fitting member 90 is press-fitted into the shaft-like member 81, the outer periphery of the press-fitting member 90 abuts against the wall surface of the counterbore portion 82 and pushes the wall surface, whereby the tip 83 of the counterbore portion 82 is deformed, and the outer side And the shaft diameter increases (the outer diameter increases). As a result, the gap S that originally existed disappears in the tip region of the counterbore part 82 (absorbs the looseness of the clearance fit and becomes loose), and the scanning optical element 10 is positioned on the YZ plane. On the other hand, positioning in the X direction is performed by friction between the tip 83 of the counterbore part 82 and the inner wall 17 of the hole part 16.

  The tip 83 opened to the outside in the counterbore part 82 is configured to bite into the inner wall 17 of the hole 16 of the scanning optical element 10 in order to improve the friction effect (positioning function in the X direction) with the inner wall 17 of the hole 16. It is preferable to do. The biting width W by the tip 83 of the counterbore part 82 is, for example, 0.3 mm, which is a small part of the inner wall 17 of the hole part 16, and its influence can be stored in a limited area of the hole part 16. Thus, the stress on the scanning optical element 10 is suppressed.

  The tip 83 of the counterbore part 82 preferably forms a chamfer 84. In this case, the press-fitting member 90 can be easily inserted, and the press-fitting member 90 functions as a guide for matching the center of the inner diameter of the counterbore part 82 with the center of the press-fitting member 90. The press-fitting member 90 is press-fitted while being automatically aligned. .

  The amount of increase in the outer diameter of the tip 83 of the counterbore part 82 can be controlled by appropriately setting the outer diameter (true spherical diameter) of the press-fitting member 90 and the shape of the counterbore part 82, for example. In consideration of machining errors, the outer diameter enlargement amount is preferably set slightly larger than the clearance fit backlash amount. In this case, the tip 83 of the counterbore part 82 bites into the inner wall 17 of the hole 16 of the scanning optical element 10 by the difference amount.

  Next, modifications 1 to 5 according to the embodiment of the present invention will be described in order.

  9 and 10 are cross-sectional views for explaining the first and second modifications according to the embodiment of the present invention.

  The press-fitting member 90 is not limited to be spherical. For example, the press-fitting member 90 has a truncated cone shape as shown in Modification 1 of FIG. 9 or a cone shape as shown in Modification 2 of FIG. Is also possible.

  FIG. 11 and FIG. 12 are a perspective view and a plan view for explaining a third modification according to the embodiment of the present invention.

  In the third modification, the counterbore part 82 of the shaft-shaped member 81 has a plurality of slits 86. The slit 86 is located on the outer periphery of the counterbore part 82 and extends in the depth direction of the counterbore part 82. The presence of the slit 86 weakens the rigidity of the counterbore part 82 (strength is reduced) and facilitates deformation (expansion) of the wall surface of the tip 83 of the counterbore part 82, thereby reducing the pressure input of the press-fitting member 90. Is possible.

  Four slits 86 are arranged at equal intervals along the outer periphery of the counterbore part 82, and are positioned so as to form an angle of 45 degrees with respect to the Y direction (main scanning direction) and the Z direction (sub scanning direction). It is preferable. In this case, the thickness of the wall surface located between the slits 86 is the same (uniform), and the outer diameter and the inner diameter of the counterbore part 82 are coaxial. Therefore, when the press-fitting member 90 is press-fitted, the wall surface of the tip 83 of the counterbore part 82 is , And tilts in the Y direction and the Z direction (equal to the left and right and back and forth), so that it is possible to effectively remove the rattling in the orthogonal biaxial direction (YZ plane). Note that the number of slits is not limited to four, and can be changed as needed.

  FIG. 13 is a plan view for explaining the modification 4 according to the embodiment of the present invention.

  The diameter expansion of the counterbore part 82 of the shaft-shaped member 81 is not limited to a form (form in which the slits 86 of the same shape are arranged at equal intervals) that are generated evenly, and if necessary, give directionality to the diameter expansion ( It is also possible to expand the diameter unevenly.

  This can be achieved by changing the width of the slit 86 and / or the interval between the slits 86. In the fourth modification, the slit 86 includes two wide slits 86A and two narrow slits 86B. The rigidity of the tip 83A located between the wide slits 86A is weak (the strength is reduced). Therefore, at the time of diameter expansion, the tip 83A of the counterbore part 82 falls preferentially in the direction of the arrow (more than the other tip 83B). That is, by changing the tilting amount of the tip 83 (83A, 83B) of the counterbore part 82 between left and right, it is possible to give directionality in the backlash direction.

  Since the shaft-like member 81 is inserted into the hole 16 of the scanning optical element 10, the relative position with respect to the optical element holder 50 changes (is biased) due to the effect of uneven diameter expansion. Therefore, when giving directionality to diameter expansion, it is preferable to arrange | position the shaft-shaped member 81 rotatably. For example, the optical performance of the scanning optical element 10 is ascertained before the counterbore portion 82 is expanded, and the relative position of the scanning optical element 10 with respect to the optical element holder 50 is changed. When the performance is improved, the press-fitting member 90 can be press-fitted and diameter-expanded after the shaft-shaped member 81 is rotated so that the direction in which the optical performance is improved and the directionality of diameter-expansion coincide.

  14 and 15 are a perspective view and a cross-sectional view for explaining a fifth modification according to the embodiment of the present invention.

  In the fifth modification, the shaft-like member 81 has a female screw portion 88, and the press-fitting member 90 has a male screw portion 92, an expansion portion 94, and a connector portion 96. The female thread portion 88 of the shaft-shaped member 81 is formed extending from the center of the bottom surface of the counterbore portion 82.

  The male screw portion 92 of the press-fitting member 90 is located at the tip end in the press-fitting direction, and is configured to be screwable (screwable) with the female screw portion 88, and the outer diameter thereof is smaller than the inner diameter of the counterbore portion 82. The extended portion 94 has a spherical shape, is located between the male screw portion 92 and the connector portion 96 (connects the male screw portion 92 and the connector portion 96), and has an outer diameter larger than the inner diameter of the counterbore portion 82. The connector part 96 has a plus groove at the tip, and is configured to be freely engageable with a cross screwdriver (not shown) to be inserted. The outer diameter of the connector part 96 is smaller than the outer diameter of the expansion part 94.

  Therefore, when the male screw portion 92 of the press-fitting member 90 is inserted into (threaded into) the female screw portion 88 of the counterbore portion 82 and is inserted into the connector portion 96 and rotated, the male screw portion 92 of the press-fit member 90 is rotated. Is advanced by being screwed into the female thread portion 88, whereby the expanded portion 94 of the press-fitting member 90 abuts against the tip 83 of the counterbore portion 82 and expands in diameter. That is, since the press-fitting of the press-fitting member 90 is executed by rotating the screwdriver, a dedicated press-fitting jig can be dispensed with. Note that the amount of collapse (the amount of diameter expansion) of the wall surface of the counterbore portion 82 can be controlled by the screwing amount of the male screw portion 92 of the press-fitting member 90.

  The extension part 94 is not limited to a spherical shape. The tip shape of the connector part 96 is not limited to the plus groove, and can be appropriately changed according to the applied screwdriver. In order to reduce the pressure input of the press-fitting member 90, a plurality of slits 86 are arranged. However, it may be omitted if necessary, or may be configured to give directionality to the diameter expansion (Modification 4). It is.

  As described above, in this embodiment, since the inner diameter of the hole of the scanning optical element is larger than the outer diameter of the shaft-shaped member of the holder, when inserting the shaft-shaped member into the hole and attaching the scanning optical element to the holder It becomes a clearance fit and does not generate stress. Therefore, the deformation of the scanning optical element and the occurrence of mounting problems are suppressed. Further, after the shaft-shaped member is inserted into the hole, the diameter of the shaft-shaped member is expanded, so that the gap between the shaft-shaped member and the hole disappears (the shaft-shaped member is thickened more than the fitting backlash). This makes it possible to position the scanning optical element with respect to the holder with high accuracy. For example, since the fitting play (gap) disappears, the position variation of the scanning optical element due to changes in the atmospheric environment may occur. It is suppressed and environmental stability is improved. Therefore, it is possible to provide a scanning optical device in which stress applied to the scanning optical element is suppressed and positioning accuracy of the scanning optical element with respect to the holder is good.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, the image forming apparatus is not limited to a copying machine, and a printer dedicated to printing, or an MFP (Multi-Function Peripheral) having a copy function, a printer function, and a scan function can also be applied. Further, the scanning optical element is not limited to the transmission optical element as shown in FIG. 2, but can be applied to a reflection optical element.

10, 10A scanning optical element,
12 protrusions,
14 semi-cylindrical part,
16 holes,
17 Inner wall,
50, 50A optical element holder,
60 X direction pressing part,
61 Reception surface,
62 sphere,
63 leaf spring,
64 holding members,
65,66 holes,
67 fastening members,
70 Z direction pressing part,
71 cylindrical member,
72 steps,
73 Sphere,
74 pressing member,
75 plane part,
76 bulbous part,
77 holes,
78 leaf spring,
80 positioning part,
81 shaft-shaped member,
82 counterbore part,
83, 83A, 83B tip,
84 Chamfering,
86 slits,
86A wide slit,
86B narrow slit,
88 female thread,
90 press-fit members,
92 Male thread,
94 Extension,
96 Connector part,
100 image forming apparatus,
110 control unit,
120 image reading unit,
122 light source,
124 optical system,
126 imaging device,
128 reading surface,
130 operation display section,
140 Image forming unit,
140A-140D image forming unit,
142 photosensitive drum,
143 charging unit,
145 optical writing unit,
146 Development device,
148 Cleaning section,
150 Transfer section,
151 Intermediate transfer belt,
153 Primary transfer part,
153A to 153D primary transfer module,
154 secondary transfer part,
155 fixing unit,
157 heating roller,
158 pressure roller,
160 paper transport section,
162 paper feeder,
162A paper feed tray,
163A delivery roller,
163B judgment roller,
164 Registration roller,
165 fixing conveyance roller,
166 paper discharge roller,
168 Paper reversing section,
170 scanning optical device,
172 light source,
174 light source holder,
176,178 optical system,
180 deflector,
182 condenser lens,
184 beam detection sensor,
186 housing,
C contact position,
D distance,
P paper,
S gap,
W bite width,
Y main scanning direction,
Z Sub-scanning direction.

Claims (11)

A long scanning optical element for forming an image of light output from the light source on the photosensitive member;
A holder to which the scanning optical element is attached;
A shaft-like member provided in the holder;
A hole provided in the scanning optical element,
The inner diameter of the hole is larger than the outer diameter of the shaft-shaped member,
The scanning optical device is positioned with respect to the holder by expanding the diameter of the shaft-shaped member after the shaft-shaped member is inserted into the hole. The shaft-shaped member has a hole portion disposed on the end face of the tip portion, and a press-fitting member press-fitted into the hole portion,
The outer diameter of the press-fitting member is smaller than the inner diameter of the hole portion of the scanning optical element and larger than the inner diameter of the hole portion of the shaft-shaped member,
The scanning optical device according to claim 1, wherein the diameter of the shaft-shaped member is increased by press-fitting the press-fitting member into the hole.   The scanning optical device according to claim 2, wherein the press-fitting member has a spherical shape or a truncated cone shape.   The scanning optical device according to claim 3, wherein the shaft-shaped member has a slit that is located on an outer periphery of the hole portion of the shaft-shaped member and extends in a depth direction of the hole portion.   The scanning optical device according to claim 4, wherein a plurality of the slits are provided.   The scanning optical device according to claim 5, wherein four slits are arranged at equal intervals along the outer periphery of the hole.   The slit is positioned so as to form an angle of 45 degrees with respect to a main scanning direction and a sub-scanning direction for forming an image of light output from the light source on a photosensitive member. 6. The scanning optical device according to 6.   The scanning optical device according to claim 5, wherein the shaft-shaped member is rotatably arranged and has directionality in the diameter expansion.   9. The scanning optical apparatus according to claim 8, wherein the directionality of the diameter expansion is set by changing a width of the slit and / or an interval of the slit. The hole of the shaft-shaped member has a female screw portion extending from the bottom surface of the hole,
The press-fitting member has a male screw part that can be screwed with the female screw part, a connector part that can be engaged with a screwdriver, and an extension part that connects the male screw part and the connector part,
The scanning optical device according to any one of claims 2 to 9, wherein an outer diameter of the extension portion is larger than an inner diameter of the hole portion of the shaft-shaped member.   The scanning optical device according to claim 1, wherein the photoconductor is a photoconductor drum of an image forming apparatus.

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