JP4617731B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer in which an optical scanning device that scans and exposes a laser beam on a photoconductor.

  In recent years, in an image forming apparatus in which an optical scanning device that scans and exposes laser light on a photoconductor is mounted, it is required to reduce the size and weight of the device body.

  As this image forming apparatus, for example, a control board and a power supply board are arranged on opposite surfaces across a paper conveyance path, and both are connected by a metal cover that protects the optical scanning device, and a common ground is used. It has been proposed (see, for example, Patent Document 1).

  In this image forming apparatus, the optical scanning device can be reinforced and reduced in weight by the metal cover. However, if the optical scanning device and the fixing device are brought close to each other in order to reduce the size of the image forming apparatus main body, there is a problem that the optical scanning device is affected by the heat of the fixing device and the scanning lines are shifted.

  As a countermeasure, for example, an image forming apparatus in which a part of a lid member is extended between an adjacent optical scanning device and a fixing device has been proposed (see, for example, Patent Document 2). .

  In this apparatus, the heat of the fixing device is insulated by the lid member, and the heat transfer to the optical scanning apparatus is reduced, so that there is an advantage that the position variation of the scanning line and the magnification variation can be prevented. However, as shown in FIG. 13, in the optical scanning device 500, there is a temperature difference on the left and right when viewed in the scanning direction due to heat generated by the polygon motor 503 that rotates the polygon mirror 502. Becomes higher than the B region. In this optical scanning device 500, the laser beam is deflected by rotation of the polygon mirror 502 and transmitted through the imaging lens 504 to scan and expose the photosensitive member 506. When the temperature rises, the scanning line is shown as indicated by the dotted line in the figure. Will spread from side to side. For this reason, when the magnification of the scanning line is compared between the left and right, there is a problem that mb ′ <ma ′, and the right and left shift occurs on the image.

  Another image forming apparatus has been proposed in which a metal member is attached to a wall in the vicinity of a position where a polygon motor of an optical scanning apparatus is attached, and heat of the polygon motor is released to the outside (for example, a patent). Reference 3).

  Although this apparatus has an advantage that the vibration of the polygon motor can be suppressed by the metal member, it is necessary to provide a slit in the wall of the optical box, the mold structure is complicated, and the cost of the mold increases. Moreover, even if a metal member is attached, a temperature difference between the left and right with respect to the scanning center occurs in the optical scanning device.

  Furthermore, a straight line connecting two fixed points where the reflecting member for detecting synchronization light of the optical scanning device is fixed to the optical box and a straight line connecting two points of the fastening portions located in the vicinity of the reflecting member are substantially An image forming apparatus configured to be vertical or substantially parallel has been proposed (see, for example, Patent Document 4).

In this image forming apparatus, even if the support portion of the reflection member expands or contracts due to an environmental change in the vicinity of the reflection member, the angle change of the optical path does not occur and the synchronization light timing does not shift. However, if there is a temperature difference between the right and left with respect to the scanning center of the optical scanning device, a temperature difference occurs between the reflecting member and the synchronizing light detection device.
Japanese Patent Laid-Open No. 2001-318496 JP 2003-287988 A JP-A-11-202238 JP 2002-357778 A

  The present invention has been made in view of the above problems, and can reduce the occurrence of a temperature difference between left and right at the scanning center of an optical scanning device, and can prevent an increase in left-right displacement on the image. An object is to provide a forming apparatus.

In order to solve the above-mentioned problems, the invention described in claim 1 is directed to an optical scanning device in which a deflector, an imaging lens system, and a synchronizing light detection device are arranged to scan and expose a photosensitive member, and a toner image as a recording medium. An image forming apparatus comprising: a fixing device that fixes the optical scanning device; and a side frame in which the optical scanning device is disposed, wherein the optical scanning device is disposed on one side of the housing and deflects a laser beam A polygon motor disposed immediately below the polygon mirror and rotating the polygon mirror in a fixed direction; an imaging lens for imaging the laser beam deflected by the polygon mirror; and facing the one side are arranged along the other side, a mirror for guiding the photosensitive drum by reflecting the imaged laser beam, and wherein the optical scanning device is attached, the optical A metal member that covers an upper surface or a lower surface of the inspection device and is spanned between the side frames; and a heat that is provided on the metal member and is located between the optical scanning device and the fixing device, and is generated from the fixing device. Is transmitted to the optical scanning device side, and the heat transfer adjustment is provided on the metal member and adjusts the heat transfer from the scanning start side to the scanning end side of the optical scanning device so as to increase. And means.

In the image forming apparatus according to claim 1, the metal member covering the upper surface or the lower surface of the optical scanning device is provided with a wall portion positioned between the optical scanning device and the fixing device, and heat generated from the fixing device is generated. It is transmitted to the optical scanning device side. The heat transferred to the wall portion is transferred from the wall portion to the metal member on the upper surface or the lower surface of the optical scanning device. Further, the heat of the metal member is transmitted to the side frame and is distributed throughout the apparatus. At that time, the heat transfer adjustment means provided on the metal member, to the scan end side than the scanning start side of the optical scanning apparatus, the transmission of the heat is adjusted to so that a lot. As a result, the temperature inside the optical scanning device can be made uniform on the left and right sides of the scanning center, and the left and right shifts on the image become substantially equal.

  Further, it is not necessary to take an expensive heat countermeasure for the heat of the fixing device, and the optical box can be reinforced by bridging the metal member on the side frame. That is, the optical box can be configured in a simple shape by reducing the reinforcement of the optical box with a complicated rib shape. Therefore, since the mold cost of the optical box can be suppressed, a small and inexpensive image forming apparatus can be realized.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the heat transfer adjusting means is connected to the metal member and the wall portion at the scanning start side with respect to the scanning center. It is the structure which formed the opening part in this.

The image forming apparatus according to claim 2, wherein an opening is formed on a scanning start side with respect to the scanning center at a connection portion between the metal member and the wall portion, and the opening portion is not formed from the wall portion. More heat is transferred to the side of the member. That is, the heat transferred from the wall portion to the metal member makes a difference between the scanning start side and the scanning end side. For this reason, it becomes possible to make the temperature inside the optical scanning device uniform on the left and right of the scanning center.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect , the heat transfer adjusting means sets the contact area of the metal member to the side frame from the scanning start side with respect to the scanning center. The scanning end side is reduced in size .

In the image forming apparatus according to claim 3, the contact area of the metal member with respect to the side frame is made smaller on the scanning end side than the scanning start side with respect to the scanning center. More heat is transferred to. That is, the heat transferred from the metal member to the side frame causes a difference between the scanning start side and the scanning end side. For this reason, it becomes possible to make the temperature inside the optical scanning device uniform on the left and right of the scanning center.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, the heat transfer adjusting means is disposed on a portion of the metal member that covers an upper surface or a lower surface of the optical scanning device with respect to the scanning center. A feature is that a plurality of apertures are formed on the scanning start side .

The image forming apparatus according to claim 4, wherein a plurality of apertures are formed on a scanning start side with respect to the scanning center at a portion of the metal member that covers the upper surface or the lower surface of the optical scanning device, and the metal member extends from the wall portion. More heat is transferred to the side where the plurality of apertures are not formed. That is, the heat transferred from the wall portion to the metal member makes a difference between the scanning start side and the scanning end side. For this reason, it becomes possible to make the temperature inside the optical scanning device uniform on the left and right of the scanning center.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the wall portion is connected to the side frame.

  In the image forming apparatus according to the fifth aspect, the wall portion is connected to the side frame, and a part of the heat transmitted from the fixing device to the wall portion is transmitted to the side frame. Thereby, the heat of the fixing device can be further dispersed. Moreover, the lateral rigidity of a side frame can be improved by connecting a wall part to a side frame.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the second aspect, the synchronous light detection device is disposed on the side opposite to the side where the contact area with the side frame is reduced. Yes.

  In the image forming apparatus according to claim 6, since the synchronization light detection device is disposed on the side opposite to the side where the contact area with the side frame is reduced, the heat transmitted from the metal member to the side frame is synchronized. More on the photo detector side. The side with a small contact area is less likely to transfer heat to the side frame, and the side with a larger contact area is likely to transfer heat to the side frame. Therefore, since the heat on the opposite side of the synchronous light detection device is difficult to escape, the temperature in the optical scanning device becomes uniform (high and uniform) on the left and right. For this reason, as in the conventional image forming apparatus, it is possible to prevent the temperature on the side of the synchronous light detection apparatus from becoming high with respect to the scanning center, and it is possible to eliminate an increase in the left / right deviation on the image.

  The invention according to claim 7 is the image forming apparatus according to claim 3 or 4, wherein the synchronous light detection device is arranged on a side where the opening or the opening is formed. It is characterized by that.

  In the image forming apparatus according to the seventh aspect, since the synchronous light detecting device is disposed on the side where the opening or the opening is formed, the light is transmitted from the wall portion to the metal member on the upper surface or the lower surface of the optical scanning device. More heat is generated on the side where no opening or hole is formed. For this reason, it is possible to make the temperature inside the optical scanning device uniform, and it is possible to eliminate an increase in the left-right shift on the image on the side of the synchronous light detection device with respect to the scanning center.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, a fan that blows heat of the fixing device to the metal member and the wall portion is provided. It is characterized by being.

  In the image forming apparatus according to the eighth aspect, since the heat of the fixing unit is blown to the metal member and the wall portion by the fan, the heat of the fixing unit can be further dispersed throughout the image forming apparatus. In particular, in the configuration in which a plurality of optical scanning devices are arranged in the image forming apparatus, the effect of dispersing the heat of the fixing device is large.

  According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the metal member has a correction unit that corrects an inclination of a scanning line of the optical scanning device. It is characterized by being provided.

  In the image forming apparatus according to the ninth aspect, the inclination of the scanning line of the optical scanning device is mechanically corrected by the correcting means provided on the metal member. For this reason, it is not necessary to adjust the inclination of the scanning line with the imaging optical system as in the conventional case, and the adjustment time can be shortened. In particular, in the configuration in which a plurality of optical scanning devices are arranged in the image forming apparatus, the inclination of the scanning line of each optical scanning device can be mechanically corrected by the correcting means, and the adjustment time can be shortened.

  According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to ninth aspects, the imaging lens system includes a plastic lens.

  In general, when the imaging lens system is formed of a plastic lens, the magnification difference due to the temperature difference becomes large. However, in the image forming apparatus according to claim 10, the temperature inside the optical scanning device is the center of the scanning. Since the left and right are uniform, it is possible to prevent the difference in magnification between the left and right from becoming large.

  According to an eleventh aspect of the present invention, in the image forming apparatus according to the fourth or seventh aspect, a plurality of the optical scanning devices are respectively attached to the metal members arranged at predetermined intervals, and the optical scanning is performed. The number of the holes is sequentially reduced as the apparatus is arranged at a position away from the fixing device.

  In the image forming apparatus according to claim 11, as the optical scanning device is arranged at a position away from the fixing device, the number of openings of the metal member covering each optical scanning device is sequentially reduced, so that the side closer to the fixing device. The metal member arranged on the left side has a large difference in heat transfer between the left and right with respect to the scanning center, and the metal member arranged on the side far from the fixing device has a small difference in heat transfer between the left and right sides. That is, a part of the heat of the fixing device is transmitted to a plurality of metal members, and the heat becomes difficult to be transmitted when it is moved away from the fixing device. Therefore, the heat is distributed to the entire image forming apparatus by making the right and left heat transfer different. . For this reason, it is possible to make the left and right temperatures uniform with respect to the scanning center in each optical scanning device, and the left and right shifts on the image are substantially equal.

  Further, in the conventional multi-color image forming apparatus, three sensors (near the start of scanning, near the center of scanning, and near the end of scanning) are required in the image forming apparatus to electrically correct the magnification. In the image forming apparatus according to the present embodiment, the left-right difference of each color is substantially uniform, so that it is only necessary to correct the overall magnification of the temperature difference of each color. Therefore, it is sufficient to provide two sensors (near the start of scanning and near the end of scanning) for electrically correcting the overall magnification, and the cost can be reduced.

  Since the image forming apparatus according to the present invention is configured as described above, the left and right temperatures are uniform with respect to the scanning center inside the optical scanning apparatus, and the left and right shifts on the image can be made substantially equal.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an image forming apparatus according to a first embodiment of the invention will be described with reference to the drawings.

  First, the overall configuration of the image forming apparatus and the outline of the printing operation will be described first, and then the main part of the present invention will be described.

  As shown in FIG. 1, the image forming apparatus 10 includes a photosensitive drum 12 on which a latent image is formed. A charging roller 14, a developing device 16, and a cleaning member are disposed along the circumferential direction of the photosensitive drum 12. A device 18 is provided. In addition, an optical scanning device 20 that irradiates laser light obliquely from above the photosensitive drum 12 is provided between the charging roller 14 and the developing device 16. On the opposite side of the photosensitive drum 12 from the optical scanning device 20, a transfer roller 22 is disposed so as to face the photosensitive drum 12.

  A paper tray 24 for stacking and storing paper and the like is disposed below the developing device 16. Paper is fed from the paper tray 24 one by one by a paper feed roller (not shown), and a transport roller 26. As a result, the sheet is conveyed to the opposite portion between the photosensitive drum 12 and the transfer roller 22. A fixing device 28 including a heating roller 29 and a pressure roller 30 pressed against the heating roller 29 is disposed downstream of the transfer roller 22 in the sheet conveyance direction.

  Two developer stirring chambers 32 and 34 are disposed on the opposite side of the developing device 16 from the photosensitive drum 12, and the developer is stirred and conveyed by an auger 36 that rotates about a support shaft 35. . Then, the developer stirred in the developer stirring chamber 32 is conveyed into the developing device 16.

  In the image forming apparatus 10, the photosensitive drum 12, the charging roller 14, the developing device 16, the developer stirring chambers 32 and 34, and the cleaning device 18 are configured as an integrated image forming unit 38. The image forming unit 38 has an opening 46 through which the laser light emitted from the optical scanning device 20 passes. The image forming apparatus 10 includes a cover 43 on the front side of the housing 40, and the image forming unit 38 can be attached to and detached from the housing 40 by opening the cover 43 downward (dotted line side). Yes. In other words, in the image forming apparatus 10, the mounting direction of the image forming unit 38 is set to the front side of the housing 40, and the conveyance direction of the sheet to the transfer roller 22 is set to the rear side of the housing 40.

  In such an image forming apparatus 10, the photosensitive drum 12 is charged to a predetermined potential by the charging roller 14 by rotation in the direction of the arrow, and the surface of the photosensitive drum 12 is irradiated with laser light from the optical scanning device 20. A latent image is formed. This latent image is developed by a developing roller 44 disposed in the developing device 16, and a toner image is formed on the surface of the photosensitive drum 12.

  On the other hand, the sheet fed from the sheet tray 24 is conveyed between the photosensitive drum 12 and the transfer roller 22 by the conveying roller 26, and the toner image on the photosensitive drum 12 is moved onto the sheet by the action of the transfer roller 22. Transcribed. The sheet is conveyed to the nip portion between the heating roller 29 and the pressure roller 30 of the fixing device 28, and the toner image is heated and melted and fixed on the sheet. Further, the surface of the photosensitive drum 12 after the toner image is transferred is cleaned by the blade 19 in the cleaning device 18 to remove the transfer residual toner.

  As shown in FIGS. 2 and 3, a substrate (not shown) on which a laser diode for emitting laser light is mounted is provided in the housing 50 of the optical scanning device 20, and is emitted from the laser diode. A regular polygonal polygon mirror 52 that deflects the laser beam is disposed downstream of the laser beam in the traveling direction. A polygon motor 54 that rotates the polygon mirror 52 in the direction of the arrow is disposed below the polygon mirror 52.

  Further, an fθ-lens 58 for forming an image of the laser beam deflected by the polygon mirror 52 on the photosensitive drum 12 is disposed in the housing 50. The fθ-lens 58 is made of plastic (for example, polymethyl methacrylate), and has a curved surface that protrudes from the central portion on the downstream side in the laser beam traveling direction. On the downstream side of the fθ-lens 58, a folding mirror 60 for reflecting the laser beam and guiding it to the photosensitive drum 12 is provided. An emission window 62 through which the laser beam reflected by the folding mirror 60 passes is formed in the lower part of the housing 50.

  In addition, a reflection mirror 64 for detecting synchronization light is disposed in front of the folding mirror 60 at the end of the laser beam scanning start side in the housing 50. At a position where the laser beam reflected by the reflecting mirror 64 is incident, a synchronization light detecting device 66 is provided for detecting the synchronization of the writing position of the laser beam in the main scanning direction.

  As shown in FIGS. 2 and 3, a metal member 70 is provided on the optical scanning device 20. A base 71 of the metal member 70 covers the upper surface of the optical scanning device 20 and is fixed to the optical scanning device 20. ing. On both sides of the base portion 71, connecting portions 72 and 74 bent upward are provided, and the connecting portions 72 and 74 are attached to the side frames 41 and 42 of the image forming apparatus 10. The connecting portion 72 is formed over the entire length of the optical scanning device 20 in the depth direction. The connecting portions 74 are formed at both end portions in the depth direction of the optical scanning device 20, and the contact area with the side frame 42 is smaller than that of the connecting portion 72. The connecting portions 72 and 74 are provided with small holes 73 and 83, respectively, and fastened to the side frames 41 and 42 with screws 75.

  Further, the metal member 70 has a wall portion 76 disposed between the optical scanning device 20 and the fixing device 28 by bending the base 71 side of the fixing device 28 downward (see FIG. 1). On both sides of the wall portion 76 in the width direction, connecting portions 77 and 78 attached to the side frames 41 and 42 are formed. The connecting portions 77 and 78 are provided with small holes 79 and fastened to the side frames 41 and 42 with screws 75.

  As shown in FIGS. 2 and 3, the bent portion of the base portion 71 and the wall portion 76 has a side where the synchronization light detection device 66 is disposed with respect to the scanning center A (the contact area between the connecting portion 72 and the side frame 41 is A long opening 80 is formed on the larger side. Further, the opposite side of the base portion 71 from the wall portion 76 is an overhang portion 82 that is bent upward.

  Next, the operation of the image forming apparatus 10 of the present invention will be described.

  In this image forming apparatus 10, laser light emitted from a laser diode (not shown) in the optical scanning device 20 is deflected by a polygon mirror 52 that is rotationally driven, passes through an fθ-lens 58, and is turned back into a mirror 60. Reflected by. The reflected laser light is applied to the photosensitive drum 12 from the exit window 62. At this time, main scanning is performed on the photosensitive drum 12 by the rotation of the polygon mirror 52, and sub scanning is performed by rotating the photosensitive drum 12 in the circumferential direction (the arrow direction in FIG. 1).

  In such an image forming apparatus 10, the wall portion 76 of the metal member 70 is disposed between the optical scanning device 20 and the fixing device 28, and heat of the fixing device 28 is insulated. Further, a part of the heat of the fixing device 28 is transmitted to the wall portion 76. The bent portion of the wall portion 76 and the base portion 71 is provided with an opening 80 on one side (the side of the connecting portion 72) with respect to the scanning center A (see FIG. 3). It is transmitted to the base 71 from the portion where 80 is not formed. Further, the heat of the base 71 is transmitted from the connecting portions 72 and 74 to the side frames 41 and 42, but the contact area between the connecting portion 74 and the side frame 42 is smaller than the contact area between the connecting portion 72 and the side frame 41. More heat is transferred to the side frame 41 from the connecting portion 72 than to the connecting portion 74. As a result, the heat of the fixing device 28 is dispersed throughout the image forming apparatus 10.

  In the conventional optical scanning device 500 (see FIG. 13), when the polygon mirror 502 is rotated, the air inside the optical scanning device 500 including heat such as a driving IC of the polygon motor 503 is swirled to the scanning center. The temperature of area A (synchronous light detection side) where laser beam scanning starts is higher than that of area B. For this reason, the shift on the synchronization light detection side becomes large on the image. On the other hand, in the optical scanning device 20 of this embodiment, as shown in FIGS. 2 and 3, the heat of the fixing device 28 is positively transmitted to the scanning end side of the optical scanning device 20, and the optical scanning device 20. The temperature inside is uniform (higher uniformity) with respect to the scanning center A. For this reason, the left and right shifts on the image are substantially equal.

  Further, it is not necessary to take an expensive heat countermeasure due to the heat of the fixing device 28, and the optical box can be reinforced by spanning the metal member 70 to the side frames 41 and 42. That is, the optical box can be configured in a simple shape by reducing the reinforcement of the optical box with a complicated rib shape. Therefore, since the mold cost of the optical box can be suppressed, the mold cost of the optical scanning device 20 can be suppressed and the side frames 41 and 42 can be reinforced, so that a small and inexpensive image forming apparatus 10 can be realized.

  Further, when the fθ-lens 58 is formed of plastic, generally, a magnification difference due to a temperature difference between the scanning start side and the scanning end side with respect to the scanning center is large. Since the left and right temperatures are uniform, the difference in magnification between the left and right can be reduced.

  Next, a second embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings.

  In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 4, in the image forming apparatus 90, a cover member 92 is provided so as to cover the upper surface of the optical scanning device 20, and a side frame (not shown) is hung on the cover member 92. A metal member 94 is provided. The metal member 94 and the cover member 92 are fixed to the optical scanning device 20. On both sides of the base portion 71 of the metal member 94, a connecting portion 72 and a connecting portion 96 that are attached to a side frame (not shown) are formed. The connecting portion 96 is provided over the entire length in the depth direction of the optical scanning device 20 and has the same contact area with the connecting portion 72 and a side frame (not shown). Further, a plurality of circular openings 98 are formed in the metal member 94 on the side where the synchronization light detection device 66 is disposed with respect to the scanning center of the base 71. These openings 98 are closed by a cover member 92 and are not inserted through the optical scanning device 20.

  Next, the operation of the image forming apparatus 90 of the present invention will be described.

  In the image forming apparatus 90, a part of the heat of the fixing device 28 is transmitted to the wall portion 76 of the metal member 94, and the heat of the wall portion 76 is transmitted to the base portion 71. A plurality of apertures 98 are formed in the base 71 on the side of the synchronous light detection device 66 with respect to the scanning center, and the heat of the wall 76 is largely transmitted to the side of the base 71 where the apertures 98 are not formed. Is done. Further, the heat of the base portion 71 is transmitted from the connecting portions 72 and 96 to the side frame (not shown).

  In this embodiment, a plurality of apertures 98 are formed in the base 71 on the side of the synchronous light detection device 66 with respect to the scanning center, and heat transfer by the fixing device 28 and the polygon motor 54 is different between the right and left with respect to the scanning center. is doing. For this reason, the temperature inside the optical scanning device 20 becomes uniform on the left and right, and the left and right shifts on the image become almost equal.

  Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings.

  In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st Embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 6, in this image forming apparatus 100, yellow, magenta, cyan, and black toner images are formed from the lower side to the upper side along the conveyance direction of the paper fed from the paper tray 102, respectively. Four image forming units 104Y, 104M, 104C, and 104K are provided. In each of the image forming units 104Y, 104M, 104C, and 104K, a charger 108, a developing device 110, and a cleaner 112 are disposed along the circumferential direction of the photosensitive drum 106. Between the charger 108 and the developing device 110, an optical scanning device 114 for irradiating the surface of the photosensitive drum 106 with laser light is provided. A transfer roller 116 is provided on the opposite side of the photosensitive drum 106 from the optical scanning device 114. Further, a fixing device 118 for fixing the toner image on the paper is disposed on the downstream side in the paper transport direction of each of the image forming units 104Y, 104M, 104C, and 104K.

  In each of the image forming units 104Y, 104M, 104C, and 104K, the photosensitive drum 106 is charged to a predetermined potential by the charger 108. Then, laser light is irradiated from the optical scanning device 114 to form an electrostatic latent image on the surface of the photosensitive drum 106. This electrostatic latent image is developed by the developing device 110, and a toner image is formed on the surface of the photosensitive drum 106. At this time, toner remaining on the surface of the photosensitive drum 106 without being transferred to the paper is collected by the cleaner 112.

  The sheets fed one by one from the sheet tray 102 are sequentially conveyed between the photosensitive drum 106 and the transfer roller 116 of each of the image forming units 104Y, 104M, 104C, and 104K by a conveyance roller (not shown). Then, yellow, magenta, cyan, and black toner images on the photosensitive drum 106 are sequentially transferred onto the sheet by the transfer roller 116. The toner images superimposed on the paper are heated and melted by a fixing device 118 installed on the downstream side in the transport direction, and the toner images are fixed on the paper.

  In this image forming apparatus 100, air in the vicinity of the fixing device 118 is moved between the image forming portion 104K and the fixing device 118 arranged at the uppermost stage in the directions of the image forming portions 104Y, 104M, 104C, and 104K (in the drawing). A fan 120 that blows in the direction of the arrow is provided.

  As shown in FIG. 7, inside the optical scanning device 114, a polygon mirror 122 for deflecting laser light, a polygon motor 124 for rotating the polygon mirror 122 in the direction of the arrow, and an image of the laser light on the photosensitive drum 106 are formed. An fθ-lens 126 is disposed. In this optical scanning device 114, no folding mirror is provided, and the photosensitive drum 106 is directly irradiated with laser light that has passed through the fθ-lens 126. A reflection mirror 128 for detecting synchronization light and a synchronization light detection device 130 are disposed on the scanning start side of the laser light.

  On the upper part of the optical scanning device 114, a metal member 132 is stretched over a side frame (not shown). The metal member 132 has connecting portions 134 and 136 in which both sides of the base portion 133 covering the upper surface of the optical scanning device 114 are bent upward, and the connecting portions 134 and 136 are attached to a side frame (not shown). It is done. The connecting portion 136 is formed over the entire length of the optical scanning device 114 in the depth direction. The connecting portions 134 are formed at both end portions of the optical scanning device 114 in the depth direction, and the contact area with a side frame (not shown) is smaller than that of the connecting portion 136.

  Further, the metal member 132 is provided with a wall portion 138 in which the fixing portion 118 side of the base portion 133 is bent upward. A long opening 140 is formed in the bent portion of the base portion 133 and the wall portion 138 on the side where the synchronous light detection device 130 is disposed with respect to the scanning center A. Further, on the opposite side of the base portion 133 from the wall portion 138, a protruding portion 141 that is bent upward is provided.

  Next, the operation of the image forming apparatus 100 of the present invention will be described.

  In this image forming apparatus 100, a fan 120 is provided below the fixing device 118, and heat of the fixing device 118 is forcibly blown to the wall portion 138 of each optical scanning device 114. As a result, part of the heat of the fixing device 118 is transmitted to the wall portion 138. The bent portion of the wall portion 138 and the base portion 133 is provided with an opening 140 on one side (on the side of the synchronous light detection device 130) with respect to the scanning center A, and the opening 140 forms the heat of the wall portion 138. It is transmitted to the base 133 from the part which is not made. Further, since the contact area between the connecting portion 134 and the side frame (not shown) with respect to the scanning center A is smaller than the contact area with the connecting portion 136, a large amount of heat is generated from the side of the connecting portion 136 (see FIG. (Not shown).

  Such a multi-color image forming apparatus 100 has a larger side frame (not shown) than the single-color image forming apparatus 10 (see FIG. 1). Can be dispersed. For this reason, the temperature inside the optical scanning device 114 becomes uniform with respect to the scanning center A, and the left and right shifts on the image become substantially equal. Furthermore, it is not necessary to take expensive heat countermeasures due to the heat of the fixing device 118, and the optical box can be reinforced by the metal member 132. That is, the optical box can be configured in a simple shape by reducing the reinforcement of the optical box with a complicated rib shape. Therefore, since the mold cost of the optical box can be suppressed, the mold cost of the optical scanning device 114 can be suppressed and the side frame (not shown) can be reinforced, so that a small and inexpensive image forming apparatus 100 can be realized.

  Further, in the conventional multi-color image forming apparatus, three sensors (near the start of scanning, near the center of scanning, and near the end of scanning) are required in the image forming apparatus to electrically correct the magnification. In the image forming apparatus 100 according to the present embodiment, the left-right difference of each color is substantially uniform, so that only correction of the overall magnification of the temperature difference of each color is required. Therefore, it is sufficient to provide two sensors (near the start of scanning and near the end of scanning) for electrically correcting the overall magnification, and the cost can be reduced.

  Next, an image forming apparatus according to a fourth embodiment of the invention will be described with reference to the drawings.

  In addition, the same code | symbol is attached | subjected to the member demonstrated in 3rd Embodiment, and the overlapping description is abbreviate | omitted.

  The overall configuration of the image forming apparatus is substantially the same as that of the image forming apparatus 100 shown in FIG. 6, but a cover member 144 is provided so as to cover the upper surface of the optical scanning device 114 as shown in FIG. A metal member 142 is disposed on the upper portion of the member 144. A plurality of circular apertures 146 are formed in the metal member 142 on the side where the synchronization light detection device 130 is disposed with respect to the scanning center of the base 133. These openings 146 are closed by a cover member 144 and are not inserted through the optical scanning device 114.

  In this image forming apparatus, more heat transferred from the fixing device (see FIG. 6) to the wall portion 138 is transferred from the side where the opening 146 is not formed to the base portion 133. Further, the heat of the base 133 is transmitted from the connecting portions 134 and 136 to a side frame (not shown).

  In this embodiment, the heat transfer by the fixing device and the polygon motor 124 differs between the right and left with respect to the scanning center, so that the temperature inside the optical scanning device 114 becomes more uniform with respect to the scanning center, and on the image. The left and right shifts are almost equal.

  Next, an image forming apparatus according to a fifth embodiment of the invention will be described with reference to the drawings.

  In addition, the same code | symbol is attached | subjected to the member demonstrated in 3rd Embodiment, and the overlapping description is abbreviate | omitted.

  The overall configuration of the image forming apparatus is substantially the same as that of the image forming apparatus 100 shown in FIG. 6, but as shown in FIG. 9, a cover member disposed at the top of the four optical scanning devices 114 (see FIG. 6). On the upper surface of 144 (see FIG. 8), metal members 150, 151, 152, and 153 having different shapes in the order from the upper stage to the lower stage are disposed. These metal members 150, 151, 152, and 153 are different in the number of circular openings 156 formed in the base portion 133, and in the upper metal member 150, the synchronous light detection device 130 with respect to the scanning center A. A plurality of apertures 156 are formed in the parabolic region on the side. As the lower metal members 151, 152, and 153 are moved away from the fixing device 118, the parabolic region becomes smaller and the number of the plurality of openings 156 decreases. These metal members 150, 151, 152, and 153 are not provided with openings as shown in FIG. 7 at the bent portions of the wall portion 138 and the base portion 133.

  In such an image forming apparatus, the number of the plurality of openings 156 formed in the metal members 150, 151, 152, and 153 is reduced from the upper stage to the lower stage, and the fixing device 118 (see FIG. 6) is used. As the distance increases, the heat transfer differs between the left and right sides. In the upper metal member 150, the number of openings 156 is large, so that more heat is transferred to the opposite side of the synchronous light detection device 130 (see FIG. 7), and as the distance from the fixing device 118 increases, Less. In other words, heat is less likely to be transferred away from the fixing device 118, so that heat is distributed throughout the image forming apparatus by making the left and right heat transfer different. For this reason, the temperature inside each optical scanning device 114 (see FIG. 6) is uniform on the left and right of the scanning center A, and the left and right on the images of the image forming units 104Y, 104M, 104C, and 104K (see FIG. 6). The deviation can be made almost equal.

  Next, a sixth embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings.

  In addition, the same code | symbol is attached | subjected to the member demonstrated in 3rd Embodiment, and the overlapping description is abbreviate | omitted.

  The overall configuration of this image forming apparatus is almost the same as that of the image forming apparatus 100 shown in FIG. 6, but the inclination of the scanning line of the optical scanning device 114 is applied to the metal member 160 disposed on the upper surface of the optical scanning device 114. Correction means 162 for correcting is provided.

  As shown in FIG. 10, the correction means 162 has a mounting portion 164 extending from one side portion of the metal member 160 on the same plane as the base portion 133, and a screw hole A of the mounting portion 164 is screwed into the screw hole A. 166 is fastened. As shown in FIG. 11, a leaf spring 168 is spanned between the attachment portion 164 and the support portion 201 formed in the opening 200 </ b> A of the side frame 200, and the leaf spring 168 is fastened with a screw 166. . Also, as shown in FIG. 12, one end side of a spring 169 is attached to the attachment portion 164, and the other end side of the spring 169 is attached to a support portion (not shown) so that the attachment portion 164 is a side portion in the front-rear direction of the opening 200A. It abuts on 200B and is urged in the direction of the arrow.

  Further, as shown in FIGS. 10 and 11, two attachment portions 170 are extended from the other side portion of the metal member 160 on the same plane as the base portion 133. The attachment portion 170 is a protruding portion 174 whose side end is bent upward, and a bent portion 172 bent downward is formed at the rear end of the attachment portion 170 in the front-rear direction. As shown in FIG. 12, the two attachment portions 170 are respectively supported by the two openings 202 </ b> A of the side frame 202, and the lateral contact portions 170 </ b> A formed in the attachment portion 170 are formed on the inner side surface 202 </ b> B of the side frame 202. Abutted. A spring 176 is bridged in the front-rear direction of the attachment portion 170 and attached to a support portion (not shown), so that it is urged in the arrow direction in FIG.

  In this image forming apparatus, the inclination of the scanning line of each optical scanning device 114 can be corrected by adjusting the screw 166 of the correcting unit 162. For this reason, it can be mechanically corrected according to the error of the image forming apparatus, and it is not necessary to correct by the imaging optical system, so that the adjustment time can be shortened.

  In the embodiment of the present invention, the shape of the openings 98, 146, 156 is circular. However, the shape is not limited to such a shape, and other shapes such as a long shape and a polygonal shape may be used. Good. Further, the openings need not have the same shape.

  In the embodiment of the present invention, the metal members 70, 94, 132, 142, 150, 160 and the like are arranged on the upper surface of the optical scanning device 20, 114, but may be provided on the lower surface of the optical scanning device. .

1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention. 1 is a perspective view showing an optical scanning device and a metal member used in an image forming apparatus according to a first embodiment of the present invention. 1 is a partially cut plan view of an optical scanning device and a metal member used in an image forming apparatus according to a first embodiment of the present invention. It is a schematic block diagram which shows the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the optical scanning device and metal member which are used with the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which shows the image forming apparatus which concerns on 3rd Embodiment of this invention. It is a perspective view which shows the optical scanning device and metal member which are used with the image forming apparatus which concerns on 3rd Embodiment of this invention. It is a perspective view which shows the optical scanning device and metal member which are used with the image forming apparatus which concerns on 4th Embodiment of this invention. It is a perspective view which shows the metal member used with the image forming apparatus which concerns on 5th Embodiment of this invention. It is a perspective view which shows the optical scanning device and metal member which are used with the image forming apparatus which concerns on 6th Embodiment of this invention. It is sectional drawing which shows the optical scanning device and metal member which are used with the image forming apparatus which concerns on 6th Embodiment of this invention. It is a top view which shows the optical scanning device and metal member which are used with the image forming apparatus which concerns on 6th Embodiment of this invention. It is a partial block diagram which shows an example of the conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Photosensitive drum 20 Optical scanning device 28 Fixing device 29 Heating roller 30 Pressure roller 40 Housing 41 Side frame 42 Side frame 50 Housing 52 Polygon mirror 54 Polygon motor 60 Mirror 64 Reflecting mirror 66 Synchronous light detection device 70 Metal Member 71 Base 72 Connecting portion 74 Connecting portion 76 Wall portion 80 Opening portion 90 Image forming device 92 Cover member 94 Metal member 96 Connecting portion 98 Opening 100 Image forming device 106 Photosensitive drum 108 Charger 110 Image forming device 114 Optical scanning device 118 Fixing Device 120 Fan 122 Polygon Mirror 124 Polygon Motor 128 Reflecting Mirror 130 Synchronous Light Detection Device 132 Metal Member 133 Base 134 Connection Portion 136 Connection Portion 138 Wall 140 Opening 142 Metal Member 144 Cover Member 146 Opening 150, 151, 152, 153 Metal member 156 Opening hole 160 Metal member 162 Correction means 164 Mounting portion 168 Leaf spring 169 Spring 170 Mounting portion 172 Bending portion 174 Overhang portion 176 Spring 200 Side frame 201 Supporting portion 202 Side frame

Claims (11)

An optical scanning device in which a deflector, an imaging lens system, and a synchronous light detection device are arranged to scan and expose a photosensitive member, a fixing device that fixes a toner image on a recording medium, and a side frame in which the optical scanning device is arranged An image forming apparatus comprising:
The optical scanning device includes a polygon mirror that is disposed on one side of the housing and deflects laser light, a polygon motor that is disposed immediately below the polygon mirror and rotates the polygon mirror in a predetermined direction, and the polygon mirror. An imaging lens for imaging the deflected laser beam; a mirror disposed along the other side opposite to the one side; and a mirror for reflecting the imaged laser beam to the photosensitive drum; With
A metal member that is mounted with the optical scanning device and covers an upper surface or a lower surface of the optical scanning device and is spanned between the side frames;
A wall provided on the metal member, located between the optical scanning device and the fixing device, and transmitting heat generated from the fixing device to the optical scanning device;
A heat transfer adjusting means provided on the metal member for adjusting the heat transfer from the scanning start side to the scanning end side of the optical scanning device so as to increase.
An image forming apparatus comprising:   2. The structure according to claim 1, wherein the heat transfer adjusting unit has a configuration in which an opening portion is formed on the scanning start side with respect to the scanning center at a connection portion between the metal member and the wall portion. Image forming apparatus.   3. The heat transfer adjusting means according to claim 2, wherein a contact area of the metal member with the side frame is configured such that the scanning end side is smaller than the scanning start side with respect to the scanning center. Image forming apparatus.   The heat transfer adjusting means has a configuration in which a plurality of apertures are formed on the scanning start side with respect to the scanning center in a portion of the metal member that covers an upper surface or a lower surface of the optical scanning device. The image forming apparatus according to claim 1.   The image forming apparatus according to claim 1, wherein the wall portion is connected to the side frame.   The image forming apparatus according to claim 2, wherein the synchronization light detection device is disposed on a side opposite to a side where a contact area with the side frame is reduced.   5. The image forming apparatus according to claim 3, wherein the synchronous light detection device is arranged on a side where the opening or the opening is formed. 6.   The image forming apparatus according to claim 1, further comprising: a fan that blows heat of the fixing unit to the metal member and the wall portion.   The image forming apparatus according to claim 1, wherein the metal member is provided with a correction unit that corrects an inclination of a scanning line of the optical scanning device.   The image forming apparatus according to claim 1, wherein the imaging lens system is configured by a plastic lens. A plurality of the optical scanning devices are respectively attached to the metal members arranged at a predetermined interval,
The image forming apparatus according to claim 4, wherein the number of the apertures is sequentially reduced as the optical scanning device is arranged at a position away from the fixing device.

Images