JP2019174517A - Optical writing device - Google Patents

Abstract

To provide an optical writing device that can suppress degradation of an optical performance.SOLUTION: An optical writing device comprises: image formation means that causes light deflected by a deflector to b image-formed on a scanned surface; and a housing 60 that holds the image formation means. The image formation means includes a scan optical member 47 that has power in a sub scan direction. The housing 60 protrudes in the sub scan direction (a z-axis direction), and includes an alignment part 61 that contacts with the scan optical member 47 in the sub scan direction. The housing 60 and the scan optical member 47 are subjected to a thick film adhesion, using an adhesive agent 53 shrinking upon hardening. The housing 60 includes a groove 63 where the adhesive agent 53 is coated. The groove 63 is a plane surface that includes an intermediate position of the sub scan direction in the groove 63, and is asymmetric with respect to the plane surface PL1 in which the sub scan direction is a normal line. When virtually segmenting the groove 63 with the plane surface PL1, a volume of the groove 63 existing on an alignment part 61 side further than the plane surface PL1 is greater than that of the groove 63 existing on a side opposite the alignment part 61 further than the plane surface PL1.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an optical writing device. More specifically, the present invention relates to an optical writing device that can suppress deterioration of optical performance.

  The electrophotographic image forming apparatus includes a scanner function, a facsimile function, a copying function, a function as a printer, a data communication function, and a server function, an MFP (Multi Function Peripheral), a facsimile apparatus, a copying machine, a printer, and the like. is there.

  Some electrophotographic image forming apparatuses form an electrostatic latent image by scanning a light beam from an optical writing device onto an image carrier. The image forming apparatus develops an electrostatic latent image using a developing unit to form a toner image, transfers the toner image to a sheet, and then fixes the toner image on the sheet by a fixing unit. Form.

  In an image forming apparatus that performs color printing, the optical writing device emits laser light for each color of Y (yellow), M (magenta), C (cyan), and K (black), and a light source. A deflector (polygon mirror) that deflects and scans the emitted light, an imaging means that forms an image of the light deflected by the deflector on the surface to be scanned, and a housing that holds the imaging means Yes. The image forming means includes a scanning optical member having power in the sub-scanning direction. The optical writing device forms an electrostatic latent image on the image carrier for each color of YMCK by performing exposure processing for irradiating the image carrier for each color of YMCK with laser light.

  FIG. 13 is a cross-sectional view schematically showing a configuration of an adhesive portion between the scanning optical member 147 and the housing 160 in the conventional optical writing apparatus. In the drawing, the z-axis direction is the sub-scanning direction, and the scanning optical member has power. The x-axis direction is the optical axis direction. The y-axis direction is the main scanning direction and is the extending direction of the scanning optical member. The x axis, the y axis, and the z axis are orthogonal to each other.

  Referring to FIG. 13, the housing 160 is in contact with the scanning optical member 147 with a positioning portion 161 protruding in the sub-scanning direction (z-axis direction), and the positioning portion 161 moves the scanning optical member 147 in the z-axis direction. Positioning is performed. Similarly, the housing 160 is in contact with the scanning optical member 147 with a positioning unit 162 protruding in the optical axis direction (x-axis direction), and the positioning unit 162 positions the scanning optical member 147 in the x-axis direction. .

  The scanning optical member 147 is bonded to the housing 160 with an adhesive 53. When the temperature around the scanning optical member 147 changes, the upper surface 53u (contact surface with the scanning optical member 147) or the lower surface of the adhesive 53 is caused by the difference in thermal expansion coefficient between the scanning optical member 147 and the housing 160. A tensile force is generated at 53v (contact surface with the housing 160). As a result, when the method of bonding the scanning optical member 147 and the housing 160 is thin film bonding, the adhesive is easily peeled off. Therefore, by adhering the scanning optical member 147 and the housing 160 by thick film bonding, the tensile force due to the difference in the thermal expansion coefficient is alleviated.

  Further, the positioning portion 162 is arranged in a direction (downward direction in FIG. 13) in which the scanning optical member 147 tends to move due to the shrinkage of the adhesive 53, so that the contraction stress σ in the optical axis direction generated by the shrinkage of the adhesive is caused. The scanning optical member 147 can be pressed against the positioning portion 162, and the displacement of the scanning optical member 147 in the optical axis direction can be effectively suppressed.

  Patent Document 1 listed below discloses a technique for fixing a scanning optical member. In Patent Document 1 below, a lens adhesive is bonded by melting a thermoplastic adhesive by infrared laser irradiation in a state where an adhesive portion formed in a leaf spring shape of a lens fixing frame is elastically displaced in a contact direction of the lens. A technique for instantly bonding to a part is disclosed. When the elastic displacement of the adhesive portion of the lens fixing frame is released, the restoring force of the adhesive portion is always generated in the anti-contact direction, and the lens and the lens fixing frame are in contact with each other at the positioning portion without using the thermoplastic adhesive.

JP 2008-216891 A

  A scanning optical member having power in the sub-scanning direction is required to have high positional accuracy not only in the optical axis direction but also in the sub-scanning direction. This is because even if the positional deviation of the scanning optical member in the sub-scanning direction is slight, the optical performance of the optical writing device is deteriorated.

  The conventional scanning optical member has a problem in that it is likely to be displaced in the sub-scanning direction due to an impact during assembly or transportation, and the optical performance of the optical writing device is likely to deteriorate.

  The present invention is for solving the above-described problems, and an object thereof is to provide an optical writing device capable of suppressing deterioration of optical performance.

  An optical writing device according to one aspect of the present invention includes a light source, a deflector that deflects and scans light emitted from the light source, and an image that forms an image of the light deflected by the deflector on a surface to be scanned. And a housing for holding the imaging means, wherein the imaging means includes a scanning optical member having power in the sub-scanning direction, and the casing projects in the sub-scanning direction. A positioning portion that contacts the scanning optical member in the sub-scanning direction, and the casing and the scanning optical member are thick-film bonded using an adhesive that shrinks when cured, and the casing is a casing to which the adhesive is applied. The housing side groove further includes a body side groove, and the housing side groove is a housing side plane including an intermediate position in the sub scanning direction in the housing side groove, and is asymmetric with respect to the housing side plane with the sub scanning direction as a normal line. When the housing side groove is virtually divided, it exists on the positioning part side of the housing side plane. The volume of the housing groove is greater than the volume of the housing groove present on the opposite side of the positioning portion than the housing-side plane.

  Preferably, in the above optical writing device, the scanning optical member includes a scanning lens having power in the sub-scanning direction, and a lens holder that holds the scanning lens and is coated with an adhesive.

  Preferably, in the above optical writing device, the lens holder includes a concave portion to which an adhesive is applied, and the concave portion is an optical member side plane including an intermediate position of the concave portion in the sub scanning direction, and the sub scanning direction is a normal line. It is symmetrical with respect to the optical member side plane.

  Preferably, in the optical writing device, the concave portion is a through hole penetrating on the opposite side of the lens holder from the side where the housing is present.

  Preferably, in the optical writing device, the region to which the adhesive is applied in the scanning optical member is a flat surface.

  An optical writing device according to another aspect of the present invention includes a light source, a deflector that deflects and scans the light emitted from the light source, and an image that forms an image of the light deflected by the deflector on the surface to be scanned. And a housing for holding the imaging means, wherein the imaging means includes a scanning optical member having power in the sub-scanning direction, and the casing projects in the sub-scanning direction. And a positioning unit that contacts the scanning optical member in the sub-scanning direction. The casing and the scanning optical member are bonded to each other with a thick film using an adhesive that shrinks when cured, and the scanning optical member is coated with an adhesive. An optical member side groove, the optical member side groove is an optical member side plane including an intermediate position in the sub scanning direction of the optical member side groove, and is asymmetric with respect to the optical member side plane having the sub scanning direction as a normal line. When the optical member side groove is virtually divided on the side plane, The volume of the optical member side groove and the positioning portion than the side plane on the opposite side is greater than the volume of the optical member side groove present in the positioning portion than the optical member side plane.

  Preferably, in the optical writing device, the region to which the adhesive is applied in the housing is a flat surface.

  In the optical writing device, preferably, the scanning optical member is long in the main scanning direction.

  According to the present invention, it is possible to provide an optical writing device capable of suppressing deterioration of optical performance.

1 is a cross-sectional view schematically showing a configuration of an image forming apparatus 1 in a first embodiment of the present invention. It is a side view which shows the structure of the optical writing apparatus 2 in the 1st Embodiment of this invention. It is a figure which shows the structure at the time of seeing the scanning optical member 47 in the 1st Embodiment of this invention from the positive side of an x-axis. Sectional drawing which shows typically the structure of the adhesion part of the scanning optical member 47 and the housing | casing 60 in the optical writing device 2 of the 1st Embodiment of this invention (sectional drawing along the IV-IV line in FIG. 3) ). It is a top view which shows the structure of the groove | channel 63 when the groove | channel 63 in the 1st Embodiment of this invention is seen from the positive side of the x-axis. It is a top view which shows the structure of the groove | channel 63 when the groove | channel 63 in the modification of the 1st Embodiment of this invention is seen from the positive side of the x-axis. 4 is a cross-sectional view schematically showing a force acting on a scanning optical member 47 in the first embodiment of the present invention. FIG. It is sectional drawing which shows typically the structure of the adhesion part of the scanning optical member 47 and the housing | casing 60 in the optical writing device 2 of the 2nd Embodiment of this invention. It is sectional drawing which shows typically the force which acts on the scanning optical member 47 in the 2nd Embodiment of this invention. It is sectional drawing which shows typically the structure of the adhesion part of the scanning optical member 47 and the housing | casing 60 in the optical writing device 2 of the 3rd Embodiment of this invention. It is a top view which shows the structure of the groove | channel 52 at the time of seeing the groove | channel 52 in the 3rd Embodiment of this invention from the negative side of an x-axis. It is sectional drawing which shows typically the force which acts on the scanning optical member 47 in the 3rd Embodiment of this invention. It is sectional drawing which shows typically the structure of the adhesion part of the scanning optical member 147 and the housing | casing 160 in the conventional optical writing device.

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

  In the following embodiment, a case where the image forming apparatus is an MFP will be described. The image forming apparatus may be a printer, a facsimile machine, a copying machine, or the like in addition to the MFP.

  [First Embodiment]

  First, the configuration of the image forming apparatus in the present embodiment will be described.

  FIG. 1 is a cross-sectional view schematically showing the configuration of the image forming apparatus 1 according to the first embodiment of the present invention.

  Referring to FIG. 1, image forming apparatus 1 in the present exemplary embodiment mainly includes a paper transport unit 10, a toner image forming unit 20, a fixing device 30, and a control unit 31.

  The paper transport unit 10 transports the paper M along the transport path TR. The paper transport unit 10 includes a paper feed tray 11, a paper feed roller 12, a plurality of transport rollers 13, a paper discharge roller 14, and a paper discharge tray 15. The paper feed tray 11 accommodates paper M for forming an image. There may be a plurality of paper feed trays 11. The paper feed roller 12 is provided between the paper feed tray 11 and the transport path TR. Each of the plurality of transport rollers 13 is provided along the transport path TR. The paper discharge roller 14 is provided in the most downstream portion of the transport path TR. The paper discharge tray 15 is provided at the top of the image forming apparatus main body 1a.

  The toner image forming unit 20 combines four color images of YMCK by a so-called tandem method, and forms a toner image on the conveyed paper M. The toner image forming unit 20 includes an optical writing device 2 (an example of an optical writing device), an image forming unit 20a for each color of YMCK, an intermediate transfer belt 22, a primary transfer roller 23 for each color of YMCK, and a secondary. And a transfer roller 24.

  The image forming units 20a for each color of YMCK are arranged in the horizontal direction in this order, and the optical writing device 2 is disposed below the image forming unit 20a for each color of YMCK. The image forming unit 20a for each color of YMCK includes a photosensitive drum 25, a charging roller 26, a developing device 28, a cleaning device 29, and the like. The photosensitive drum 25 is rotationally driven in a direction indicated by an arrow α in FIG. A charging roller 26, a developing device 28, and a cleaning device 29 are provided around the photosensitive drum 25.

  The intermediate transfer belt 22 is provided above the image forming unit 20a for each color of YMCK. The intermediate transfer belt 22 has an annular shape and is stretched around a rotating roller 22a. The intermediate transfer belt 22 is rotationally driven in a direction indicated by an arrow β in FIG. Each of the primary transfer rollers 23 faces each of the photosensitive drums 25 with the intermediate transfer belt 22 interposed therebetween. The secondary transfer roller 24 is in contact with the intermediate transfer belt 22 in the transport path TR.

  The fixing device 30 fixes the toner image on the paper M by transporting the paper carrying the toner image along the transport path TR while gripping the paper.

  The control unit 31 includes a CPU (Central Processing Unit) that controls the entire image forming apparatus 1 according to a control program, a ROM (Read Only Memory) that stores the control program, and a RAM (Random Access Memory) that forms a work area of the CPU. Etc.

  The image forming apparatus 1 rotates the photosensitive drum 25 and charges the surface of the photosensitive drum 25 with the charging roller 26. The image forming apparatus 1 performs exposure according to the image formation information by the optical writing device 2 on the charged surface of the photosensitive drum 25 to form an electrostatic latent image on the surface of the photosensitive drum 25.

  Next, the image forming apparatus 1 performs development by supplying toner from the developing device 28 to the photosensitive drum 25 on which the electrostatic latent image is formed, and forms a toner image on the surface of the photosensitive drum 25.

  Next, the image forming apparatus 1 sequentially transfers the toner image formed on the photosensitive drum 25 onto the surface of the intermediate transfer belt 22 using the primary transfer roller 23 (primary transfer). In the case of a full-color image, a toner image obtained by combining toner images of YMCK colors is formed on the surface of the intermediate transfer belt 22.

  The image forming apparatus 1 uses a cleaning device 29 to remove toner remaining on the photosensitive drum 25 without being transferred to the intermediate transfer belt 22.

  Subsequently, the image forming apparatus 1 conveys the toner image formed on the surface of the intermediate transfer belt 22 to a position facing the secondary transfer roller 24 by the rotation roller 22a.

  On the other hand, the image forming apparatus 1 feeds the paper M stored in the paper feed tray 11 by the paper feed roller 12, and each of the plurality of transport rollers 13 and the secondary transfer belt 22 along the transport path TR. Guided to the transfer roller 24. Then, the image forming apparatus 1 transfers the toner image formed on the surface of the intermediate transfer belt 22 onto the paper M by the secondary transfer roller 24.

  The image forming apparatus 1 guides the paper M on which the toner image is transferred to the fixing device 30, and fixes the toner image on the paper M by the fixing device 30. Thereafter, the image forming apparatus 1 discharges the paper M on which the toner image is fixed to the paper discharge tray 15 by the paper discharge roller 14.

  Next, the configuration of the optical writing device in the present embodiment will be described.

  FIG. 2 is a side view showing the configuration of the optical writing device 2 according to the first embodiment of the present invention.

  Referring to FIG. 2, the optical writing device 2 includes a light source 41 (an example of a light source), a deflector 42 (an example of a deflector), an imaging unit 43 (an example of an imaging unit), and a housing 60. And. The housing 60 accommodates the light source 41, the deflector 42, and the imaging unit 43, and holds the light source 41, the deflector 42, and the imaging unit 43.

  The light source 41 is a semiconductor laser device, for example, and emits laser light for each color of YMCK. The laser light emitted from the light source 41 passes through a collimator lens, a cylindrical lens (not shown), etc., and enters the mirror surface of the deflector 42.

  The deflector 42 is composed of a polygon mirror, and deflects and scans the light emitted from the light source 41. The deflector 42 rotates a polygon mirror having a plurality of reflecting surfaces on its side surface by a motor, deflects and scans the laser light incident on the reflecting surface.

  The imaging unit 43 images each of the four lights deflected by the deflector 42 on the surface of each of the four photosensitive drums 25. The imaging unit 43 includes a lens 44, reflection mirrors 45Y, 45M, 45C, and 45Y, scanning optical members 47Y, 47M, 47C, and 47K (an example of a scanning optical member), auxiliary reflection mirrors 49Y, 49M, and 49C. Each of the scanning optical members 47Y, 47M, 47C, and 47K has power in the sub-scanning direction.

  The reflection mirror 45Y, the scanning optical member 47Y, and the auxiliary reflection mirror 49Y are optical elements for yellow (Y). The reflection mirror 45Y reflects the yellow laser beam LY deflected by the deflector 42 and passed through the lens 44. Each of the scanning optical member 47Y and the auxiliary reflecting mirror 49Y transmits the laser beam LY reflected by the reflecting mirror 45Y, and reflects the laser beam LY toward the surface of the photosensitive drum 25 for yellow.

  The reflection mirror 45M, the scanning optical member 47M, and the auxiliary reflection mirror 49M are magenta (M) optical elements. The reflection mirror 45M reflects the magenta laser light LM deflected by the deflector 42 and passed through the lens 44. Each of the scanning optical member 47M and the auxiliary reflecting mirror 49M transmits the laser beam LM reflected by the reflecting mirror 45M, and reflects the laser beam LM toward the surface of the photosensitive drum 25 for magenta.

  The reflection mirror 45C, the scanning optical member 47C, and the auxiliary reflection mirror 49C are optical elements for cyan (C). The reflection mirror 45C reflects the cyan laser light LC that has been deflected by the deflector 42 and passed through the lens 44. Each of the scanning optical member 47C and the auxiliary reflecting mirror 49C transmits the laser light LC reflected by the reflecting mirror 45C, and reflects the laser light LC toward the surface of the cyan photosensitive drum 25.

  The reflection mirror 45K and the scanning optical member 47K are black (K) optical elements. The reflection mirror 45K reflects the black laser light LK deflected by the deflector 42 and passed through the lens 44. The scanning optical member 47M transmits the laser beam LK reflected by the reflecting mirror 45K and irradiates the surface of the photosensitive drum 25 for black.

  Hereinafter, any of the scanning optical members 47Y, 47M, 47C, and 47K may be referred to as the scanning optical member 47.

  Then, the structure of the bonded part in the scanning optical member 47 and the housing | casing 60 is demonstrated.

  FIG. 3 is a diagram showing a configuration when the scanning optical member 47 according to the first embodiment of the present invention is viewed from the positive side of the x-axis. FIG. 4 is a cross-sectional view schematically showing a configuration of a bonding portion between the scanning optical member 47 and the housing 60 in the optical writing device 2 according to the first embodiment of the present invention (in the line IV-IV in FIG. 3). It is sectional drawing along). Note that, in the cross-sectional views of FIGS. 4, 7 to 10, 12, and 13, the positioning portion 62 and the region RG <b> 2 do not actually appear, but are shown for convenience of explanation.

  3 and 4, the scanning optical member 47 and the housing 60 are bonded to each other with a thick film using an adhesive 53 (an example of an adhesive). Thick film adhesion means adhesion with an adhesive having a thickness of 0.5 mm or more (length in the x-axis direction). The adhesive 53 has a property of shrinking when cured. The adhesive 53 may be thermosetting or photocurable.

  The scanning optical member 47 includes a lens holder 51 (an example of a lens holder) and a scanning lens 59 (an example of a scanning lens). The scanning lens 59 has power in the sub-scanning direction (z-axis direction) and is long in the main scanning direction (y-axis direction). The lens holder 51 holds the scanning lens 59. The lens holder 51 is long in the main scanning direction and includes a hole 51a formed at the center in the main scanning direction. A scanning lens 59 is fitted in the hole 51a. An adhesive 53 is applied to the regions RG1 at both ends of the lens holder 51 in the main scanning direction. Region RG1 is a plane.

  The housing 60 has an L shape when viewed in the cross section of FIG. 4 and includes positioning portions 61 (an example of a positioning portion) and 62 and a groove 63 (an example of a housing side groove). . The positioning part 61 (an example of a positioning part) is for fixing the position of the scanning optical member 47 in the sub-scanning direction. The positioning unit 61 protrudes in the sub scanning direction and is in contact with the lens holder 51 in the sub scanning direction. The positioning unit 62 is for fixing the position of the scanning optical member 47 in the optical axis direction (x-axis direction). The positioning part 62 protrudes in the optical axis direction and is in contact with the region RG2 of the lens holder 51 in the optical axis direction.

  The groove 63 is formed in a region RG3 to which the adhesive 53 is applied in the housing 60. An adhesive 53 is applied in the groove 63. The groove 63 includes a bottom surface 63a that is a plane parallel to the region RG1 of the lens holder 51 and a bottom surface 63b that is a plane (slope) inclined with respect to the region RG1 of the lens holder 51. The bottom surface 63b is provided on the opposite side of the positioning portion 61 from the bottom surface 63a, and the depth of the groove 63 in the bottom surface 63b is gradually shallower than the depth of the groove 63 in the bottom surface 63a.

  FIG. 5 is a plan view showing the configuration of the groove 63 when the groove 63 is viewed from the positive side of the x-axis in the first embodiment of the present invention.

  Referring to FIG. 5, a plane including an intermediate position in the sub-scanning direction in groove 63 and having a normal to the sub-scanning direction is referred to as plane PL1 (an example of a housing side plane). Since groove 63 includes bottom surfaces 63a and 63b, groove 63 is asymmetric with respect to plane PL1. Further, when the groove 63 is virtually divided on the plane PL1, the volume V1a of the groove 63 present on the positioning portion 61 side from the plane PL1 is the groove 63 present on the opposite side of the positioning portion 61 from the plane PL1. Is larger than the volume V1b.

  FIG. 6 is a plan view showing the configuration of the groove 63 when the groove 63 in the modification of the first embodiment of the present invention is viewed from the positive side of the x-axis.

  Referring to FIG. 6, groove 63 is asymmetric with respect to plane PL1, and volume V1a of groove 63 present on positioning part 61 side with respect to plane PL1 is on the opposite side of positioning part 61 with respect to plane PL1. It only needs to be larger than the volume of the groove 63. In this modification, when the groove 63 is viewed in plan from the positive side of the x-axis, the area of the groove 63 existing on the positioning part 61 side with respect to the plane PL1 is opposite to the positioning part 61 with respect to the plane PL1. It is larger than the area of the groove 63 existing on the side. The bottom surface of the groove 63 is configured only by a plane parallel to the region RG1 of the lens holder 51, and does not include a plane (slope) inclined with respect to the region RG1 of the lens holder 51. As a result, the groove 63 is asymmetric with respect to the plane PL1, and the volume V1a of the groove 63 existing on the positioning part 61 side with respect to the plane PL1 is the volume of the groove 63 existing on the opposite side of the positioning part 61 with respect to the plane PL1. It is larger than V1b.

  Next, the effect of the optical writing device in the present embodiment will be described.

  Referring to FIG. 13, in the conventional configuration, the portion to which adhesive 53 is applied in scanning optical member 147 and the portion to which adhesive 53 is applied in housing 160 are both flat.

  The adhesive 53 tries to shrink by a length Lx in the x-axis direction during curing, but since the scanning optical member 147 is positioned by the positioning unit 162, it cannot move in the negative x-axis direction. . As a result, the cured adhesive 53 is stretched by a length Lx in the x-axis direction. On the upper surface 53u (the surface in contact with the scanning optical member 147) and the lower surface 53v (the surface in contact with the housing 160) of the cured adhesive 53, the adhesive 53 has a length Lx in the x-axis direction. It will be in the state where contraction stress (sigma) 1 generated by being extended was added. When the Young's modulus of the adhesive 53 is E, the shrinkage stress σ1 is expressed by the following formula (1).

  Shrinkage stress σ1 = Lx / E (1)

  On the other hand, since both side surfaces 53w of the adhesive 53 are not restrained, the adhesive 53 contracts by a length Lz in the z-axis direction during curing. Furthermore, since the adhesive 53 cannot shrink in the x-axis direction, it further shrinks by ΔLz in the z-axis direction during curing in an attempt to compensate for shrinkage in the x-axis direction. When the adhesive 53 contracts by ΔLz in the z-axis direction, the contraction stress σ1 is relaxed by the stress σ2. The stress σ2 is expressed by the following formula (2).

  Stress σ2 = ΔLz / E (2)

  As a result, a shrinkage stress σ expressed by the following formula (3) is applied to the cured adhesive 53 in the x-axis direction.

  Shrinkage stress σ = σ1−σ2 = (Lx−ΔLz) / E (3)

  The contraction stress σ acts as a force for pressing the scanning optical member 147 in the direction of the positioning portion 162, and the contraction force of the adhesive 53 is used to suppress displacement of the scanning optical member 147 in the optical axis direction (x-axis direction). be able to. On the other hand, in the conventional configuration, the shrinkage stress in the z-axis direction out of the shrinkage stress generated during curing cancels each other. For this reason, the contractive force of the adhesive 53 cannot be used to suppress the displacement of the scanning optical member 147 in the sub-scanning direction (z-axis direction).

  FIG. 7 is a cross-sectional view schematically showing the force acting on the scanning optical member 47 in the first embodiment of the present invention.

  Referring to FIGS. 7 and 13, when the groove 63 is present in the region to which the adhesive 53 is bonded (in the case of FIG. 7), x is compared with the case without the groove 63 (in the case of FIG. 13). The axial shrinkage stress σ1 increases. On the other hand, since the area of both side surfaces 53w of the adhesive 53 is hardly changed, the shrinkage amount ΔLz in the z-axis direction is hardly changed, and the stress σ2 for relaxing the shrinkage stress σ1 is hardly changed. As a result, according to the present embodiment, the groove 63 is provided, so that the planar area of the region to which the adhesive 53 is bonded is not changed, and the adhesive 53 generated during curing in the x-axis direction is changed. The shrinkage stress σ can be increased.

  Referring to FIG. 7, adhesive 53 applied between region RG3a in the groove 63 near the side surface on the positioning portion 61 side and region RG1a on the opposite side to positioning portion 61 in region RG1 of lens holder 51 is referred to. This portion is referred to as an adhesive 53a (FIG. 7A). The portion of the adhesive 53 applied between the bottom surface 63b provided on the opposite side of the positioning portion 61 in the groove 63 and the region RG1b on the positioning portion 61 side in the region RG1 of the lens holder 51 is the adhesive 53b ( FIG. 7B).

  In the present embodiment, groove 63 is asymmetric with respect to plane PL1, and volume V1a of groove 63 present on positioning portion 61 side with respect to plane PL1 is a groove on the opposite side of positioning portion 61 with respect to plane PL1. It is larger than 63 volume V1b. For this reason, the magnitude of the shrinkage stress σa (FIG. 7A) generated when the adhesive 53a is cured is larger than the magnitude of the contraction stress σb (FIG. 7B) generated when the adhesive 53b is cured. large. A force corresponding to a vector V (FIG. 7A) obtained by subtracting the z-axis component of the contraction stress σb from the z-axis component of the contraction stress σa always acts as a force for pressing the lens holder 51 toward the positioning unit 61. As a result, the shrinkage force of the adhesive 53 can be used to suppress the displacement of the scanning optical member 47 in the sub-scanning direction (z-axis direction). Even when receiving an impact during assembly or transportation, the scanning optical member 47 is unlikely to be displaced in the sub-scanning direction, and deterioration of the optical performance of the optical writing device 2 can be suppressed.

  Furthermore, since the scanning optical member 47 holds the scanning lens 59 with the lens holder 51, the deformation of the scanning lens 59 due to the contraction stress when the adhesive 53 is cured can be suppressed.

  [Second Embodiment]

  FIG. 8 is a cross-sectional view schematically showing a configuration of an adhesive portion between the scanning optical member 47 and the housing 60 in the optical writing device 2 according to the second embodiment of the present invention.

  Referring to FIG. 8, in the present embodiment, lens holder 51 includes a through hole 54 (an example of a recess) formed at a position opposite to the position where adhesive 53 is applied in housing 60. . An adhesive 53 is applied to the inside of the through hole 54 in a range including the side surface 54a. The through hole 54 penetrates from the side of the lens holder 51 where the housing 60 exists (the negative side of the x axis) to the side opposite to the side where the housing 60 exists (the positive side of the x axis). A plane including an intermediate position in the sub-scanning direction (z-axis direction) in the through hole 54 and having a normal line in the sub-scanning direction is defined as a plane PL2 (an example of an optical member side plane). The through hole 54 is symmetric with respect to the plane PL2.

  The configurations of the image forming apparatus and the optical writing device in the present embodiment other than those described above are the same as the configurations of the image forming apparatus and the optical writing device in the first embodiment, and thus description thereof will not be repeated. .

  FIG. 9 is a cross-sectional view schematically showing the force acting on the scanning optical member 47 in the second embodiment of the present invention.

  Referring to FIG. 9, according to the present embodiment, since lens holder 51 is bonded by adhesive 53 in through hole 54, the bonding surface of the lens holder is not a plane parallel to the sub-scanning direction. The side surface 54a can be a side surface that is inclined with respect to the sub-scanning direction (preferably a surface perpendicular to the sub-scanning direction). As a result, the force (the magnitude of the vector V) for pressing the lens holder 51 in the direction of the positioning portion 161 can be increased.

  In addition, when the adhesive 53 is a photocurable adhesive, light (ultraviolet rays) is transmitted to the adhesive 53 through the through hole 54 from the downstream side in the optical axis direction of the scanning optical member 47 (the positive side of the x axis). The adhesive 53 can be cured by irradiating AR. As a result, even when the groove 63 is deep, the adhesive 53 applied in the groove 63 can be easily cured, and the workability of bonding can be improved.

  In addition, the through-hole 54 in this Embodiment may be the recessed part which has not penetrated to the opposite side (positive side of x-axis) from the side where the housing | casing 60 exists. In this case, the light AR cannot be applied to the adhesive 53 through the through hole 54, but the force (the magnitude of the vector V) for pressing the lens holder 51 in the direction of the positioning portion 161 is increased as in the case of the through hole 54. I can.

  [Third Embodiment]

  FIG. 10 is a cross-sectional view schematically showing a configuration of an adhesion portion between the scanning optical member 47 and the housing 60 in the optical writing device 2 according to the third embodiment of the present invention.

  Referring to FIG. 10, in the present embodiment, region RG3 to which adhesive 53 is applied in housing 60 is a flat surface. The lens holder 51 includes a groove 52 (an example of an optical member side groove). The groove 52 is formed in a region RG1 where the adhesive 53 in the lens holder 51 is applied. An adhesive 53 is applied in the groove 52. The groove 52 includes a ceiling surface 52a which is a plane parallel to the region RG3 of the housing 60 and a ceiling surface 52b which is a plane (slope) inclined with respect to the region RG3 of the housing 60. The ceiling surface 52b is provided closer to the positioning portion 61 than the ceiling surface 52a, and the depth of the groove 52 in the ceiling surface 52b gradually decreases from the depth of the groove 52 in the ceiling surface 52a.

  FIG. 11 is a plan view showing the configuration of the groove 52 when the groove 52 according to the third embodiment of the present invention is viewed from the negative side of the x-axis.

  Referring to FIG. 11, a plane including an intermediate position in the sub-scanning direction in groove 52 and having a normal in the sub-scanning direction is defined as plane PL3 (an example of an optical member side plane). Since groove 52 includes ceiling surfaces 52a and 52b, groove 52 is asymmetric with respect to plane PL3. Further, when the groove 52 is virtually divided on the plane PL3, the volume V2b of the groove 52 existing on the opposite side of the positioning portion 61 from the plane PL3 is the groove 52 existing on the positioning portion 61 side of the plane PL3. Is larger than the volume V2a.

  The configurations of the image forming apparatus and the optical writing device in the present embodiment other than those described above are the same as the configurations of the image forming apparatus and the optical writing device in the first embodiment, and thus description thereof will not be repeated. .

  Next, the effect of the optical writing device in the present embodiment will be described.

  FIG. 12 is a cross-sectional view schematically showing the force acting on the scanning optical member 47 in the third embodiment of the present invention.

  Referring to FIG. 12, according to the present embodiment, by providing groove 52, adhesive 53 that is generated during curing can be obtained without changing the planar area of the region to which adhesive 53 is bonded. The shrinkage stress σ in the x-axis direction can be increased.

  The portion of the adhesive 53 applied between the ceiling surface 52b provided on the positioning portion 61 side in the groove 52 and the region RG3c on the opposite side of the positioning portion 61 in the region RG3 of the housing 60 is the adhesive 53c. (FIG. 12A). The portion of the adhesive 53 applied between the region RG1c near the side surface of the groove 52 opposite to the positioning portion 61 and the region RG3d on the positioning portion 61 side in the region RG3 of the housing 60 is the adhesive 53d ( FIG. 12B).

  In the present embodiment, groove 52 is asymmetric with respect to plane PL3, and volume V2b of groove 52 that is on the opposite side of positioning part 61 from plane PL3 is a groove that is on the side of positioning part 61 relative to plane PL3. It is larger than the volume V2a of 52. For this reason, the magnitude of the shrinkage stress σd (FIG. 12B) generated when the adhesive 53d is cured is larger than the magnitude of the contraction stress σc (FIG. 12A) generated when the adhesive 53c is cured. large. A force corresponding to a vector V (FIG. 12B) obtained by subtracting the z-axis component of the contraction stress σc from the z-axis component of the contraction stress σd always acts as a force for pressing the lens holder 51 toward the positioning unit 61. As a result, the shrinkage force of the adhesive 53 can be used to suppress the displacement of the scanning optical member 47 in the sub-scanning direction (z-axis direction). Even when receiving an impact during assembly or transportation, the scanning optical member 47 is unlikely to be displaced in the sub-scanning direction, and deterioration of the optical performance of the optical writing device 2 can be suppressed.

  [Others]

  In the above-described embodiment, the case where the scanning optical member is configured by the lens holder and the scanning lens has been described. However, the scanning optical member only needs to have power in the sub-scanning direction, and a mirror is used instead of the lens. It may be. Further, the scanning optical member may not include a holder, and an adhesive may be directly applied to a lens or a mirror.

  The above-described embodiments and modifications can be combined as appropriate.

  The above-described embodiments and modifications should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1a Image forming apparatus main body 2 Optical writing apparatus (an example of an optical writing apparatus)
DESCRIPTION OF SYMBOLS 10 Paper transport part 11 Paper feed tray 12 Paper feed roller 13 Transport roller 14 Paper discharge roller 15 Paper discharge tray 20 Toner image forming part 20a Image forming unit 21 Optical writing device 22 Intermediate transfer belt 22a Rotating roller 23 Primary transfer roller 24 Two Next transfer roller 25 Photosensitive drum 26 Charging roller 28 Developing device 29 Cleaning device 30 Fixing device 31 Control unit 41 Light source (an example of a light source)
42 Deflector (an example of a deflector)
43 Imaging part (an example of imaging means)
44 Lens 45C, 45K, 45M, 45Y Reflective mirror 47, 47C, 47K, 47M, 47Y, 147 Scanning optical member (an example of a scanning optical member)
49C, 49M, 49Y Auxiliary reflection mirror 51 Lens holder (an example of a lens holder)
51a Lens holder hole 52, 63 groove (an example of a housing side groove and an optical member side groove)
52a, 52b Groove ceiling surface 54 Through hole (an example of a recess)
54a Side surface of through hole 53, 53a, 53b, 53c, 53d Adhesive (an example of an adhesive)
53u, 53v, 53w Adhesive surface 59 Scan lens (an example of a scan lens)
60,160 case (example of case)
61, 62, 161, 162 Positioning part (an example of a positioning part)
63a, 63b Bottom surface of groove AR light LC, LK, LM, LY Laser light M paper PL1, PL2, PL3 plane (an example of housing side plane and optical member side plane)
RG1, RG1a, RG1b, RG1c, RG2, RG3, RG3a, RG3c, RG3d region TR transport path V vector V1a, V1b, V2a, V2b volume ΔLz shrinkage σ, σ1, σ2, σa, σb, σc, σd stress

Claims (8)

A light source;
A deflector that deflects and scans the light emitted from the light source;
Imaging means for imaging light deflected by the deflector on a scanned surface;
An optical writing device comprising a housing for holding the imaging means,
The imaging means includes a scanning optical member having power in the sub-scanning direction,
The housing includes a positioning portion that protrudes in the sub-scanning direction and contacts the scanning optical member in the sub-scanning direction,
The casing and the scanning optical member are thick-film bonded using an adhesive that shrinks when cured,
The case further includes a case side groove to which the adhesive is applied,
The housing-side groove is a housing-side plane including an intermediate position in the sub-scanning direction in the housing-side groove, and is asymmetric with respect to the housing-side plane having the normal in the sub-scanning direction,
When the housing-side groove is virtually divided on the housing-side plane, the volume of the housing-side groove existing on the positioning unit side with respect to the housing-side plane is more than the positioning portion than the housing-side plane. An optical writing device having a volume larger than the volume of the housing side groove existing on the opposite side.   The optical writing device according to claim 1, wherein the scanning optical member includes a scanning lens having power in the sub-scanning direction, and a lens holder that holds the scanning lens and is coated with the adhesive. The lens holder includes a recess to which the adhesive is applied,
3. The optical document according to claim 2, wherein the concave portion is an optical member side plane including an intermediate position in the sub scanning direction in the concave portion, and is symmetric with respect to the optical member side plane having the sub scanning direction as a normal line. Device.   The optical writing device according to claim 3, wherein the concave portion is a through hole penetrating to a side of the lens holder opposite to a side where the housing is present.   The optical writing apparatus according to claim 1, wherein a region to which the adhesive is applied in the scanning optical member is a flat surface. A light source;
A deflector that deflects and scans the light emitted from the light source;
Imaging means for imaging light deflected by the deflector on a scanned surface;
An optical writing device comprising a housing for holding the imaging means,
The imaging means includes a scanning optical member having power in the sub-scanning direction,
The housing includes a positioning portion that protrudes in the sub-scanning direction and contacts the scanning optical member in the sub-scanning direction,
The casing and the scanning optical member are thick-film bonded using an adhesive that shrinks when cured,
The scanning optical member includes an optical member side groove to which the adhesive is applied,
The optical member side groove is an optical member side plane including an intermediate position in the sub scanning direction in the optical member side groove, and is asymmetric with respect to the optical member side plane having the sub scanning direction as a normal line,
When the optical member-side groove is virtually divided on the optical member-side plane, the volume of the optical member-side groove existing on the opposite side of the positioning portion side from the optical member-side plane is the optical member-side plane. An optical writing device that is larger than the volume of the optical member side groove present on the positioning part side.   The optical writing device according to claim 6, wherein a region to which the adhesive is applied in the housing is a flat surface.   The optical writing device according to claim 1, wherein the scanning optical member is long in a main scanning direction.

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