JP2012083406A - Optical scanner and image forming device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner capable of stably and surely adhering and fixing a lens to a housing without generating cost increase or giving a harmful effect to optical characteristics.SOLUTION: In the optical scanner, at least a light source, a deflector for deflecting a light beam emitted from the light source and an imaging lens 3 for converting the light beam deflected by the deflector into a scanning light having a constant velocity are housed in a housing 25, and the imaging lens 33 is fixed on a lens supporting part 25C of the housing 25 by supporting both ends in the main scanning direction of the imaging lens 33 by the lens supporting part 25C of the housing 25 and adhering the both ends in the main scanning direction of the imaging lens 33 and the lens supporting part 25C with an adhesive 50. A plurality of concave parts 33b are formed on adhesive surfaces 33a of the both ends in the main scanning direction of the imaging lens 33 along the main scanning direction.

Description

  The present invention relates to an optical scanning device for optically scanning a photoreceptor and an image forming apparatus such as a copying machine and a printer provided with the optical scanning device.

  In an image forming apparatus such as a copying machine or a printer, a photoconductor whose surface is uniformly charged by a charger is optically scanned by an optical scanning device, and an electrostatic latent image corresponding to image information is formed on the surface. . The electrostatic latent image is developed by a developing device using toner as a developer to be visualized as a toner image. The toner image is transferred onto a sheet by a transfer device and then heated and heated by a fixing device. A series of image forming operations is completed by discharging the sheet having the toner image fixed thereon by being pressed and fixed on the sheet.

  By the way, an optical scanning device that optically scans a photosensitive member to form an electrostatic latent image on a surface thereof includes a light source, a deflector that deflects a light beam emitted from the light source, and light deflected by the deflector. An imaging lens (fθ lens) that converts the beam into constant speed scanning light, a folding mirror that folds the constant speed scanning light and guides it to the photosensitive member, and the like are accommodated in the housing.

  The imaging lens provided in such an optical scanning device generally has a long shape in the main scanning direction in order to cover a predetermined scanning width, and the fixing structure to the housing is imaged by a leaf spring. There is a configuration in which the lens is pressed against the reference surface, but this structure has a problem that the number of components increases and a die for mass production of the members becomes necessary, resulting in an increase in cost.

  Therefore, Patent Document 1 proposes a method of fixing the imaging lens to the housing with an adhesive without using a leaf spring. The fixing structure proposed in Patent Document 1 is such that when the adhesive surface of the lens and the support reference surface of the mounting base are separated from each other, the adhesive that fixes the lens to the mounting base is cured and contracted. Focusing on the point that the surface is displaced in the direction of the mount, in order to prevent the displacement of the support reference plane, as shown in the sectional view of FIG. 8, the mount 101 has a support reference point P for supporting the lens 102. A support column 103 having 103a formed on the upper surface is provided, and the lens 102 and the support reference point P are brought into contact with each other, so that the surface of the projection 103a, the upper surface of the support column 103, the upper surface of the support column 103, and the support reference point P of the lens 102 are provided. The adhesive 104 is bonded to the peripheral part of the contact part. According to this fixing structure, the displacement in the mounting direction of the lens 102 (downward in FIG. 8) caused by the contraction of the adhesive 104 is reduced, the mounting accuracy of the lens 102 is increased, and the lens 102 has desired optical characteristics. Secured.

JP 7-175000 A

  However, the fixing structure proposed in Patent Document 1 focuses only on the posture change of the lens 102, and does not consider the influence of repeated thermal stress due to the linear expansion coefficient between the lens 102 and the mounting base 101. This repeated thermal stress generates a shearing force at the bonding part between the lens and the lens support part of the housing when the environmental temperature changes from the bonding temperature. When this shearing force is repeatedly applied to the bonding part, the bonding part breaks. As a result, there arises a problem that the lens is peeled off from the lens support portion.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical scanning apparatus capable of stably and surely fixing and fixing a lens to a housing without adversely affecting cost and optical characteristics. An object of the present invention is to provide an image forming apparatus provided with this.

  To achieve the above object, according to the first aspect of the present invention, at least a light source, a deflector for deflecting a light beam emitted from the light source, and a light beam deflected by the deflector are scanned at a constant speed. A lens for converting light is accommodated, both ends of the lens in the main scanning direction are supported by the lens support portions of the housing, and both ends of the lens in the main scanning direction and the lens support portions are bonded with an adhesive. In the optical scanning device in which the lens is fixed to the lens support portion of the housing, a plurality of recesses are formed along the main scanning direction on the adhesive surfaces at both ends of the lens in the main scanning direction.

  According to a second aspect of the present invention, at least a light source, a deflector for deflecting a light beam emitted from the light source, and a lens for converting the light beam deflected by the deflector into constant-speed scanning light are accommodated in the housing. Then, both ends of the lens in the main scanning direction are supported by the lens supporting portions of the housing, and the lens is housed by adhering the adhesive surfaces of the both ends of the lens in the main scanning direction to the lens supporting portions. In the optical scanning device fixed to the lens support portion, a plurality of non-adhesive portions are provided on the lens support portion of the housing.

  According to a third aspect of the present invention, at least a light source, a deflector for deflecting a light beam emitted from the light source, and a lens for converting the light beam deflected by the deflector into constant-speed scanning light are accommodated in the housing. And supporting both ends of the lens in the main scanning direction by the lens support portions of the housing and adhering both ends of the lens in the main scanning direction and the lens support portions with an adhesive. A plurality of concave portions are formed along the main scanning direction on the bonding surfaces of both ends of the lens in the main scanning direction, and a plurality of non-bonding portions are formed on the lens support portion of the housing. It is provided.

  An image forming apparatus according to a fourth aspect includes the optical scanning device according to any one of the first to third aspects.

  According to the first aspect of the present invention, since the plurality of recesses are formed along the main scanning direction on the bonding surfaces at both ends in the main scanning direction of the lens, the shear stress can be reduced by increasing the bonding distance of the lens. The adhesion area of the adhesion surface of the lens is enlarged by the recess, and both end portions in the main scanning direction of the lens are firmly fixed to the lens support portion of the housing. For this reason, the lens can be stably and reliably fixed to the lens support portion of the housing even if a shearing force due to thermal stress is repeatedly applied to the bonding portion. In addition, since a member such as a leaf spring is not used for fixing the lens, the number of parts is reduced, the cost is reduced, and distortion or the like is not generated in the lens, so that high optical characteristics are secured in the lens.

  According to the second aspect of the present invention, since the plurality of non-adhesive portions are provided in the lens support portion of the housing, a reaction force against the shearing force generated on the adhesion surface side of the lens is not generated in the adherend portion of the lens support portion. Therefore, the shearing force of the bonded portion is reduced. For this reason, even if thermal stress is repeatedly generated in the adhesive portion due to the difference in linear expansion coefficient between the lens and the housing, the lens is stably and securely fixed to the lens support portion of the housing, and the lens is prevented from peeling off. It is. Also in the present invention, since a member such as a leaf spring is not used for fixing the lens, the number of parts is reduced, the cost is reduced, and the lens is not distorted. Therefore, the lens has high optical characteristics. Secured. If a plurality of non-adhesive portions are provided on the lens support portion of the housing, the adhesion area of the lens support portion is reduced. However, since the housing is made of polycarbonate ABS or the like having high adherence, There is no shortage of adhesive strength to the lens support.

  According to the third aspect of the present invention, the plurality of concave portions are formed along the main scanning direction on the bonding surfaces at both ends in the main scanning direction of the lens, and the plurality of non-bonding portions are provided in the lens support portion of the housing. Since the bonding area of the lens bonding surface is enlarged by the concave portion to increase the bonding strength of the lens and the shearing force of the bonding portion is reduced due to a plurality of non-bonding portions formed on the lens support portion of the housing. Even if thermal stress is repeatedly generated in the adhesive portion due to the difference in linear expansion coefficient between the housing and the housing, the lens is stably and securely fixed to the lens support portion of the housing, and the lens is prevented from peeling off. Also in the present invention, since a member such as a leaf spring is not used for fixing the lens, the number of parts is reduced, the cost is reduced, and the lens is not distorted. Therefore, the lens has high optical characteristics. Secured.

  According to the fourth aspect of the present invention, since the lens of the optical scanning device is securely bonded and secured, and high optical characteristics are ensured for the lens, a high-quality image can be stably obtained.

1 is a side sectional view of an image forming apparatus (color laser printer) according to the present invention. It is a top view which shows the internal structure of the optical scanning device based on 1st invention. It is the sectional view on the AA line of FIG. It is the B section enlarged detail drawing of FIG. CC sectional view taken on the line of FIG. It is a figure similar to FIG. 5 which shows the lens fixing structure of the optical scanning device based on 2nd invention. It is a figure similar to FIG. 5 which shows the lens fixing structure of the optical scanning device based on 3rd invention. It is sectional drawing which shows the conventional lens fixing structure.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

[Image forming apparatus]
FIG. 1 is a cross-sectional view of a color laser printer as an embodiment of an image forming apparatus according to the present invention. The illustrated color laser printer is a tandem type, and a magenta image forming unit is provided at the center of the main body 100. 1M, a cyan image forming unit 1C, a yellow image forming unit 1Y, and a black image forming unit 1K are arranged in tandem at regular intervals.

  In each of the image forming units 1M, 1C, 1Y, and 1K, photosensitive drums 2a, 2b, 2c, and 2d, which are photosensitive members, are arranged, respectively, and around each of the photosensitive drums 2a to 2d, a charger 3a, 3b, 3c, 3d, developing devices 4a, 4b, 4c, 4d, transfer rollers 5a, 5b, 5c, 5d and drum cleaning devices 6a, 6b, 6c, 6d are arranged, respectively.

  Here, the photosensitive drums 2a to 2d are drum-shaped photosensitive members, and are driven to rotate at a predetermined process speed in a direction indicated by an arrow (clockwise) by a driving motor (not shown). The chargers 3a to 3d uniformly charge the surfaces of the photosensitive drums 2a to 2d to a predetermined potential by a charging bias applied from a charging bias power source (not shown).

  Further, the developing devices 4a to 4d contain magenta (M) toner, cyan (C) toner, yellow (Y) toner, and black (K) toner, respectively, and are formed on the photosensitive drums 2a to 2d. In addition, the toner of each color is attached to each electrostatic latent image, and each electrostatic latent image is visualized as a toner image of each color.

  The transfer rollers 5a to 5d are arranged so as to be able to contact the photosensitive drums 2a to 2d via the intermediate transfer belt 7 in the respective primary transfer portions. Here, the intermediate transfer belt 7 is stretched between the driving roller 8 and the tension roller 9 and is disposed on the upper surface side of each of the photosensitive drums 2a to 2d. The driving roller 8 is a secondary roller. The transfer unit is disposed so as to be in contact with the secondary transfer roller 10 via the intermediate transfer belt 7. A belt cleaning device 11 is provided in the vicinity of the tension roller 9.

  Incidentally, toner containers 12a, 12b, 12c, and 12d for supplying toner to the developing devices 4a to 4d are arranged in a line above the image forming units 1M, 1C, 1Y, and 1K in the printer main body 100. It is installed.

  Further, below the image forming units 1M, 1C, 1Y, and 1K in the printer main body 100, two optical scanning devices 13 are arranged in parallel in the paper transport direction, and the printer main body below these optical scanning devices 13 is provided. A paper feed cassette 14 is detachably installed at the bottom of 100. A plurality of sheets of paper (not shown) are stacked and stored in the paper feed cassette 14. A pickup roller 15 for picking up paper from the paper feed cassette 14 and a picked up paper are located near the paper feed cassette 14. A feed roller 16 and a retard roller 17 are provided for separating the toner and feeding them one by one to the transport path S.

  Further, the conveyance path S extending in the vertical direction on the side of the printer main body 100 includes a conveyance roller pair 18 that conveys the sheet, and the secondary transfer counter roller 8 and the second transfer opposing roller 8 at a predetermined timing after the sheet is temporarily held. A registration roller pair 19 is provided to be supplied to a secondary transfer portion which is a contact portion with the next transfer roller 10. Next to the transport path S, another transport path S ′ that is used when images are formed on both sides of the paper is formed. A plurality of reversing roller pairs 20 are appropriately used for the transport path S ′. Are provided at regular intervals.

  By the way, the conveyance path S arranged in the vertical direction on one side of the printer main body 100 extends to the paper discharge tray 21 provided on the upper surface of the printer main body 100, and the fixing device 22 and the discharge path are disposed in the middle. Paper roller pairs 23 and 24 are provided.

  Next, an image forming operation by the color laser printer having the above configuration will be described.

  When an image formation start signal is issued, the photosensitive drums 2a to 2d are driven to rotate at a predetermined process speed in the direction of the arrow (clockwise) in the image forming units 1M, 1C, 1Y, and 1K, and these photosensitive drums 2a. ˜2d are uniformly charged by the chargers 3a to 3d. Each optical scanning device 13 emits a light beam modulated by a color image signal for each color, irradiates the surface of each photosensitive drum 2a to 2d with each light beam, and each color on each photosensitive drum 2a to 2d. The electrostatic latent images corresponding to the color image signals are respectively formed.

  First, magenta toner is attached to the electrostatic latent image formed on the photosensitive drum 2a of the magenta image forming unit 1M by the developing device 4a to which a developing bias having the same polarity as the charged polarity of the photosensitive drum 2a is applied. The electrostatic latent image is visualized as a magenta toner image. This magenta toner image is moved in the direction of the arrow in the figure by the action of the transfer roller 5a to which a primary transfer bias having a polarity opposite to that of the toner is applied in the primary transfer portion (transfer nip portion) between the photosensitive drum 2a and the transfer roller 5a. Primary transfer is performed on the intermediate transfer belt 7 that is rotationally driven.

  The intermediate transfer belt 7 on which the magenta toner image has been primarily transferred as described above moves to the next cyan image forming unit 1C. In the cyan image forming unit 1C as well, the cyan toner image formed on the photosensitive drum 2b is transferred to the magenta toner image on the intermediate transfer belt 7 in the primary transfer portion in the same manner as described above.

  Similarly, yellow and black toners respectively formed on the photosensitive drums 2c and 2d of the yellow and black image forming units 1Y and 1K on the magenta and cyan toner images superimposed and transferred on the intermediate transfer belt 7, respectively. The images are sequentially superimposed at each primary transfer portion, and a full-color toner image is formed on the intermediate transfer belt 7. The transfer residual toner which is not transferred onto the intermediate transfer belt 7 and remains on the photosensitive drums 2a to 2d is removed by the drum cleaning devices 6a to 6d, and the photosensitive drums 2a to 2d are prepared for the next image formation. It is done.

  Then, in accordance with the timing at which the front end of the full-color toner image on the intermediate transfer belt 7 reaches the secondary transfer portion (transfer nip portion) between the drive roller 8 and the secondary transfer roller 10, The sheet fed to the transport path S by the feed roller 16 and the retard roller 17 is transported to the secondary transfer unit by the registration roller pair 19. Then, a full-color toner image is collectively transferred from the intermediate transfer belt 7 to the sheet conveyed to the secondary transfer unit by the secondary transfer roller 10 to which a secondary transfer bias having a polarity opposite to that of the toner is applied. .

  Thus, the sheet on which the full-color toner image has been transferred is conveyed to the fixing device 22, and the sheet on which the full-color toner image has been fixed by being heated and pressurized and thermally fixed on the surface of the sheet. Then, the paper is discharged onto the paper discharge tray 21 by the paper discharge roller pair 23 and 24, and a series of image forming operations is completed. The transfer residual toner that is not transferred onto the sheet and remains on the intermediate transfer belt 7 is removed by the belt cleaning device 11, and the intermediate transfer belt 7 is prepared for the next image formation.

[Optical scanning device]
<First invention>
Next, the basic configuration and operation of the optical scanning device 13 according to the first invention will be described with reference to FIGS. 2 is a plan view showing the internal structure of one optical scanning device according to the first invention, and FIG. 3 is a cross-sectional view taken along line AA of FIG. Note that since the basic configuration of the two optical scanning devices 13 provided in the color laser printer shown in FIG.

  The optical scanning device 13 has a housing 25 integrally formed of resin. As shown in FIG. 3, the housing 25 has a horizontal base 25A that vertically divides the inside and a frame surrounding the periphery. The side wall 25B is formed in an H-shaped side section. A polygon mirror 26 serving as a deflector is disposed at the center of the upper surface of the base 25A of the housing 25, and the upper and lower spaces defined by the base 25A in the housing 25 are centered on the polygon mirror 26. Two scanning optical systems 30 and 40 are arranged symmetrically on both sides.

  The scanning optical systems 30 and 40 include laser diodes 31 and 41 that are light sources disposed on the upper surface of the substrate 25 </ b> A in the housing 25. Each laser diode 31 and 41 has a collimator lens (not shown) incorporated therein.

  Thus, the light beam L emitted from each of the laser diodes 31 and 41 is condensed into a linear light beam by a collimator lens (not shown), and then rotated to a polygon mirror 26 that is driven to rotate at a predetermined speed. Incident from two symmetrical directions. The light beams L incident on the polygon mirror 26 are deflected by the polygon mirror 26, and the scanning optical systems 30 and 40 are arranged along the traveling direction of the light beam L on the upper surface side of the base 25A. The first imaging lenses 32 and 42, the second imaging lenses 33 and 43, the first folding mirrors 34 and 44, and the second folding mirror 35 disposed along the traveling direction of the light beam L on the lower surface side of the base 34A. , 35 and third folding mirrors 36, 46, respectively.

  By the way, one optical scanning device 13 shown in FIGS. 2 and 3 exposes and scans the photosensitive drum 2a of the magenta image forming unit 1M and the photosensitive drum 2b of the cyan image forming unit 1C shown in FIG. On the optical path connecting the third folding mirrors 36, 46 and the photosensitive drums 2a, 2b constituting the scanning optical systems 30, 40, and between the first imaging lenses 32, 42 and the second imaging lenses 33, 43. Are formed with respective first openings 25a, and second openings 25b are formed on the optical path connecting the first folding mirrors 34, 44 and the second folding mirrors 35, 45 of the substrate 25A.

  On the other hand, as shown in FIG. 2, each scanning optical system 30, 40 has a side next to the second imaging lenses 33, 43 on the base 25 </ b> A on which the polygon mirror 26 is disposed, and the polygon mirror 26 is the center. Synchronous detectors (BD sensors) 37 and 47 are respectively arranged at the point symmetry positions. These synchronization detectors 37 and 47 are arranged outside the effective scanning range of the photosensitive drums 2a and 2b by the light beam L, and by detecting the synchronization detection light beam L ′, the photosensitive drums by the light beam L. The start timing of exposure scanning (writing) onto 2a and 2b is determined.

  In each of the scanning optical systems 30 and 40, the light beam L ′ for synchronization detection is reflected on the lower surface of the base 25A and outside the effective scanning range (a point symmetrical position with the polygon mirror 26 as the center). Synchronous detection mirrors 38 and 48 for guiding to the synchronous detectors 37 and 47 are arranged, respectively.

  Thus, in the present embodiment, the first folding mirrors 34 and 44 and the second folding mirrors 35 and 45 are arranged in the middle of the synchronization detection optical path from the polygon mirror 26 to the synchronization detection mirrors 38 and 48, respectively. Has been. In addition, first imaging lenses 32 and 42 and second imaging lenses 33 and 43 are disposed in the middle of the synchronization detection optical path from the polygon mirror 26 to the first folding mirrors 34 and 44, respectively.

  Thus, the light beam L emitted from the laser diodes 31 and 41 provided in the scanning optical systems 30 and 40 in one optical scanning device 13 is condensed into a linear light beam by a collimator lens (not shown). Then, the light enters the polygon mirror 26 rotated at a predetermined speed from two symmetrical directions.

  As described above, each light beam L incident on the polygon mirror 26 is deflected by the polygon mirror 26 and then passes through the first imaging lenses 32 and 42 and the second imaging lenses 33 and 43 so as to perform constant velocity scanning. It is converted into light L. The constant-speed scanning light L is folded downward at a right angle by the first folding mirrors 42 and 44, passes through the second opening 25b formed in the base 25A, and the second folding mirrors 35 and 45. The second folding mirrors 35 and 45 are folded at a right angle and proceed horizontally along the lower surface of the substrate 25A. Thereafter, the light beam L is folded upward at a right angle by the third folding mirrors 36 and 46, passes through the first opening 25a formed in the substrate 25A, toward the photosensitive drums 2a and 2b, and these photosensitive drums 2a. , 2b are exposed and scanned.

  2 and FIG. 3 performs exposure scanning on the photosensitive drum 2a of the magenta image forming unit 1M and the photosensitive drum 2b of the cyan image forming unit 1C shown in FIG. The color laser printer shown in FIG. 1 is provided with two similar optical scanning devices 13 arranged side by side, and these two optical scanning devices 13 use the photosensitive drums 2c of the other yellow image forming unit 1Y and Bralac image forming unit 1K. , 2d, all of the four photosensitive drums 2a to 2d are exposed and scanned by the light beam L.

  The synchronous detection light beam L ′ deflected by the polygon mirror 26 is narrowed by passing through the first imaging lenses 32 and 42 and the second imaging lenses 33 and 43, and then the first folding mirror. 34 and 44 are folded downward at a right angle, pass through a second opening 25b formed in the base 25A, reach the second folding mirrors 35 and 45, and are folded at a right angle by the second folding mirrors 35 and 45. Then, it proceeds horizontally along the lower surface of the substrate 25A and reaches the synchronization detection mirrors 38 and 48. Thereafter, the light beam L ′ is reflected by the synchronization detection mirrors 38 and 48 and reaches the second folding mirrors 35 and 45, and is reflected again by the second folding mirrors 35 and 45, and is folded upward at a right angle, thereby returning the base 25A. Passing through the second opening 25b formed on the first and second mirrors 34 and 44 again.

  The light beam L ′ is folded at a right angle by the first folding mirrors 34 and 44, travels in parallel along the upper surface of the base 25 A and is guided to the synchronization detectors 37 and 47. As a result, the timing for starting exposure scanning (writing) onto the photosensitive drums 2a and 2b by the light beam L is determined as described above. In this embodiment, as shown in FIG. 3, the length of the synchronization detection optical path from the polygon mirror 26 to the synchronization detectors 37 and 47 is set to the length of the scanning optical path from the polygon mirror 26 to the photosensitive drums 2a and 2b. It is set approximately equal to the length.

  By the way, the first imaging lenses 32 and 42 and the second imaging lenses 33 and 43 provided in the scanning optical systems 30 and 40, respectively, are bonded and fixed to the housing 25 by an adhesive. A fixing structure of the lens 33 (hereinafter simply referred to as “imaging lens”) will be described with reference to FIGS. 4 and 5.

  4 is an enlarged detailed view of a portion B in FIG. 2, and FIG. 5 is a sectional view taken along the line CC in FIG. 4 and 5 show only the fixing structure of one end portion in the main scanning direction (left end portion in FIG. 2) of the imaging lens 33, the fixing structure of the other end portion in the main scanning direction (right end portion in FIG. 2) is shown. Since they are the same, illustration and explanation thereof are omitted.

  The imaging lens 33 is made of a cyclic olefin resin or the like that hardly changes over time due to moisture absorption or the like, and has an arcuate shape (bow shape) in plan view that is long in the main scanning direction (left-right direction in FIG. 2) to cover a predetermined scanning width. It has a shape. Then, fixed portions 33A extending in the left-right direction in FIG. 2 are formed in parallel to both ends in the main scanning direction of the imaging lens 33 (left-right both ends in FIG. 2).

  Further, as shown in FIG. 5, a lens support portion 25C is formed in the housing 25, and the upper surface of the lens support portion 25C constitutes a horizontal and flat support surface (adhesion surface) 25c. The housing 25 is made of polycarbonate ABS or the like having high adhesion.

  Thus, in the present embodiment, as shown in FIG. 5, the adhesive surface 33a, which is the lower surface of the imaging lens 33, has a plurality of concave portions 33b having a triangular cross section (mountain shape) in the main scanning direction (left and right in FIG. 5). The adhesive surface 33a of the imaging lens 33 forms a saw blade shape by these concave portions 33b.

  The imaging lens 33 has an adhesive surface 33a, which is the lower surface of the fixed portion 33A at both ends in the main scanning direction, placed on the support surface 25c of the lens support portion 25C of the housing 25, and an adhesive interposed therebetween. By adhering them together by 50, both ends in the main scanning direction are bonded and fixed onto the lens support portion 25C of the housing 25. Note that a curable resin or the like is used as the adhesive 50.

  By the way, since the linear expansion coefficients of the housing 25 made of polycarbonate ABS and the like and the laminated lens 33 made of cyclic olefin resin or the like are not the same, the lens of the imaging lens 33 and the housing 25 when the environmental temperature changes from the bonding temperature. Shear forces f1 and f2 indicated by solid line arrows in FIG. 5 are generated on the imaging lens 33 side of the adhesion part with the support part 25C, and the reverse direction indicated by the broken line arrow in FIG. 5 is provided on the lens support part 25C side of the housing 25. Shearing forces f1 ′ and f2 ′ are generated. When these shearing forces f1, f2, and f1 ', f2' are repeatedly applied to the bonded portion, the imaging lens 33 made of a cyclic olefin resin or the like having a particularly low adherence may be peeled off.

  However, in the present invention, since the plurality of concave portions 33b are formed along the main scanning direction on the bonding surface 33a of the fixed portion 33A at both ends of the imaging lens 33 in the main scanning direction, the bonding distance of the imaging lens 33 is increased. The shearing stress is reduced, and the bonding area of the bonding surface 33a of the imaging lens 33 is expanded by the plurality of concave portions 33b, so that both end portions in the main scanning direction of the imaging lens 33 are firmly attached to the lens support portion 25C of the housing 25. Bonded and fixed. For this reason, the imaging lens 33 can be stably and reliably fixed to the lens support portion 25C of the housing 25 even if shearing forces f1, f2 and f1 ′, f2 ′ due to repeated thermal stress act on the bonding portion. Further, peeling of the imaging lens 33 can be surely prevented.

  Further, in the present invention, since a member such as a leaf spring is not used for fixing the imaging lens 33, the number of parts is reduced, the cost is reduced, and the imaging lens 33 is not distorted. High optical characteristics are secured in the image lens 33, and a high-quality color image can be stably obtained in the color laser printer shown in FIG.

  In the embodiment of the present invention, the triangular (mountain-shaped) concave portion 33b is formed on the bonding surface 33a of each fixing portion 33A of the imaging lens 33. However, the concave portion 33b has an arbitrary shape and has a waveform. The bonding surface 33c may be a sinusoidal uneven surface by the recess 33b.

<Second invention>
Next, a lens fixing structure in the optical scanning device according to the second invention will be described below with reference to FIG.

  FIG. 6 is a view similar to FIG. 5 showing the lens fixing structure of the optical scanning device according to the second invention. In FIG. 6, the same elements as those shown in FIG. The re-explanation about them is omitted.

  The present invention is characterized in that a plurality of concave portions 25d are formed as non-adhesive portions on the support surface 25c of the lens support portion 25 of the housing 25 at appropriate intervals in the main scanning direction (left-right direction in FIG. 6). When the plurality of recesses 25d are formed on the support surface 25c of the lens support portion 25 of the housing 25 in this way, the adhesive 50 does not enter the recesses 25d due to surface tension, and therefore the recesses of the support surface 25c of the lens support portion 25C. The portion where 25d is formed becomes a non-adhesive portion that does not contribute to the adhesion of the imaging lens 33, and the portion other than the concave portion 25d of the support surface 25c contributes to the adhesion of the imaging lens 33. The viscosity of the adhesive 50 and the size of the recess 25d are set so that the adhesive 50 does not enter the recess 25d due to surface tension.

  As described above, in the present invention, the lens support portion 25C of the housing 25 is provided with the plurality of concave portions 25d as non-adhesive portions, and therefore the support surface 25c of the lens support portion 25C is generated on the adhesive surface 33a side of the imaging lens 33. The reaction force against the shearing force f2 is not generated, thereby reducing the shearing force of the bonded portion. For this reason, the imaging lens 33 is stably and securely fixed to the lens support portion 25C of the housing 25 even if thermal stress is repeatedly generated in the bonding portion due to the difference in coefficient of linear expansion between the imaging lens 33 and the housing 25. As a result, the imaging lens 33 is prevented from peeling off.

  Also in the present invention, since a member such as a leaf spring is not used for fixing the imaging lens 33, the number of parts is reduced, the cost is reduced, and the imaging lens 33 is not distorted. High optical characteristics are secured in the imaging lens 33. If a plurality of concave portions 25d are provided as non-adhesive portions on the lens support portion 25C of the housing 25, the adhesion area of the support surface 25c of the lens support portion 25C is reduced, but the material of the housing 25 is highly adherent. Since polycarbonate ABS or the like is used, the adhesive strength of the imaging lens 33 to the lens support portion 25C will not be insufficient.

<Third invention>
Next, a lens fixing structure in the optical scanning device according to the third invention will be described below with reference to FIG.

  FIG. 7 is a view similar to FIG. 5 showing the lens fixing structure of the optical scanning device according to the third invention. In this figure, the same elements as those shown in FIG. 5 and FIG. In the following, a repetitive description thereof will be omitted.

  The present invention is a combination of the first invention and the second invention. That is, a plurality of concave portions 33b having a triangular cross section (mountain shape) are formed in the adhesive surface 33a of the imaging lens 33 in the main scanning direction (left-right direction in FIG. 7), and at the support surface 25c of the lens support portion 25 of the housing 25 A plurality of recesses 25d are formed as non-bonding portions.

  Therefore, according to the present invention, the shear stress is reduced by increasing the bonding distance of the imaging lens 33, and the bonding area of the bonding surface 22a of the imaging lens 33 is enlarged by the recess 33b. The adhesive strength is increased, and the shearing force of the adhesive portion is reduced due to the plurality of concave portions 25d formed in the lens support portion 25C of the housing 25, which is caused by a difference in linear expansion coefficient between the imaging lens 33 and the housing 25. Thus, even if thermal stress is repeatedly generated in the bonded portion, the imaging lens 33 is stably and reliably fixed to the lens support portion 25C of the housing 25, and the imaging lens 33 is prevented from peeling off. Also in the present invention, since a member such as a leaf spring is not used for fixing the imaging lens 33, the number of parts is reduced, the cost is reduced, and the imaging lens 33 is not distorted. High optical characteristics are secured in the imaging lens 33.

  In the embodiment described above, a configuration is adopted in which the adhesive surface, which is the lower surface of the imaging lens, is adhered and fixed to the horizontal support surface of the lens support portion of the housing. You may employ | adopt the structure adhere | attached on the vertical support surface of a part. Although the present invention has been described with respect to a mode in which the present invention is applied to a color laser printer and an optical scanning device provided in the color laser printer, the present invention is provided in any image forming apparatus other than a color printer and the same. Of course, the present invention can be similarly applied to the optical scanning device.

1M Magenta image forming unit 1C Cyan image forming unit 1Y Yellow image forming unit 1K Black image forming unit 2a to 2d Photosensitive drum (photoconductor)
3a to 3d charger 4a to 4d developing device 5a to 5d transfer roller 6a to 6d drum cleaning device 7 intermediate transfer belt 8 drive roller 9 tension roller 10 secondary transfer roller 11 belt cleaning device 12a to 12d toner container 13 optical scanning device 14 Paper cassette 15 Pickup roller 16 Feed roller 17 Retard roller 18 Transport roller pair 19 Registration roller pair 20 Transport roller pair 21 Paper discharge tray 22 Fixing device 23, 24 Paper discharge roller pair 25 Housing 25A Housing base 25B Housing side wall 25C Housing Lens support portion 25a First opening portion 25b of housing Second opening portion 25c of housing 25c Support surface of lens support portion 25d Recessed portion of lens support portion (non-adhesive portion)
26 Polygon mirror (deflector)
30, 40 Scanning optical system 31, 41 Laser diode (light source)
32, 42 First imaging lens 33, 43 Second imaging lens 33A Imaging lens fixing part 33a Imaging lens fixing part adhesive surface 33b Imaging lens adhesive surface concave part 34, 44 First folding mirror 35 , 45 Second folding mirror 36, 46 Third folding mirror 37, 47 Third reflection mirror 38, 48 Synchronization detector 37, 47 Synchronization detection mirror 50 Adhesive L, L ′ Light beam S, S ′ Transport path

Claims (4)

The housing contains at least a light source, a deflector that deflects the light beam emitted from the light source, and a lens that converts the light beam deflected by the deflector into constant speed scanning light, and the main scanning direction of the lens Both ends are supported by the lens support portion of the housing, and the lens is fixed to the lens support portion of the housing by adhering both ends of the lens in the main scanning direction and the lens support portion with an adhesive. In the device
An optical scanning device, wherein a plurality of concave portions are formed along the main scanning direction on the bonding surfaces at both ends of the lens in the main scanning direction. The housing contains at least a light source, a deflector that deflects the light beam emitted from the light source, and a lens that converts the light beam deflected by the deflector into constant speed scanning light, and the main scanning direction of the lens Both ends are supported by the lens support portion of the housing, and the lens is fixed to the lens support portion of the housing by bonding the adhesive surfaces of the both ends of the lens in the main scanning direction and the lens support portion with an adhesive. An optical scanning device comprising:
An optical scanning device comprising a plurality of non-adhesive portions provided on a lens support portion of the housing. The housing contains at least a light source, a deflector that deflects the light beam emitted from the light source, and a lens that converts the light beam deflected by the deflector into constant speed scanning light, and the main scanning direction of the lens Both ends are supported by the lens support portion of the housing, and the lens is fixed to the lens support portion of the housing by adhering both ends of the lens in the main scanning direction and the lens support portion with an adhesive. In the device
An optical scanning device comprising: a plurality of concave portions formed along the main scanning direction on the bonding surfaces at both ends of the lens in the main scanning direction; and a plurality of non-bonding portions provided on the lens support portion of the housing. An image forming apparatus comprising the optical scanning device according to claim 1.

Images