JP2006267143A - Optical scanner and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical scanner capable of suppressing a temperature rise inside an image forming apparatus, and to obtain an image forming apparatus using the same. <P>SOLUTION: In the optical scanner 6, each exposing light beam emitted from a plurality of light sources is made incident, deflected and scanned relative to a single deflector and, after transmitted through a single optical system, separately emitted to a plurality of photoreceptors arranged with equal spaces apart in the subscanning direction to form an electrostatic latent image on each photoreceptor. The lower part of the housing of the optical scanner 6 is designed to be a tapered face, in which the optical axis center expanding upward to the outside orthogonally to the optical axis is made the lowest part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical scanning device used in an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction printer, and more particularly to a high-speed printing, high resolution, tandem type image forming apparatus corresponding to a wide paper width, and It is effective when applied to the exhaust heat of a small tandem image forming apparatus installed on a disk top and disk side.

  2. Description of the Related Art Conventionally, there has been proposed an image forming apparatus that operates stably with low cost and efficient exhaust heat so as not to overheat the image forming apparatus (see Patent Document 1).

  Here, FIG. 15 is a cross-sectional view showing the back side including the photoreceptor in the conventional image forming apparatus.

  In FIG. 15, in the housing 28 of the image forming apparatus 27, one shaft of the photosensitive member 2, which is an image carrier, is incorporated by being supported by a bearing 30 of a frame 29. A plurality of electric boards 31 incorporating a large number of complicated electronic circuit parts controlled by a microcomputer for operating the image forming apparatus 27 so as to satisfy various functions are provided in the lower part on the back side of the housing 28. Is incorporated.

  Various electrical components and the like incorporated in the electric substrate 31 include the influence of the environmental temperature in the housing 28 due to heat radiation of devices and members mainly including a fixing device (not shown) incorporated in the housing 28. The various electrical components incorporated in the circuit 31 are easily affected by heat dissipation.

  A flywheel 32 for preventing uneven rotation of the photosensitive member 2 is attached to the tip of the rotating shaft 37 of the photosensitive member 2 by an attachment member 34 attached to one surface of the flywheel 32 with a flange 33. Yes. A blower blade 35 is attached to the other surface of the flywheel 32 by a gutter 33 so that air can be blown in the direction of arrow A by the rotation of the photosensitive member 2.

  A large number of air holes 36 are provided in the casing 28 in the vicinity of the electric board 31 as shown in the figure. The air holes 36 are blown in the direction of arrow A by the blower blades 35 attached to the flywheel 32 described above. It is provided at a position corresponding to. Therefore, the flow of air blown in the direction of arrow A by the blower blades 35 escapes from the air hole 36 to the outside of the housing 28. At that time, the air flow in the direction of arrow B, which is lightened by being heated by the electrical components of the electric board 31, is also attached to the outside of the housing 28 through the air hole 36 along with the air flow in the direction of arrow A. The air flows in the direction of arrow C to the left and exits.

  Due to the air flow thus generated, the air that has been heated and lightened by the electrical components around the electrical substrate 31 flows out of the housing 28 through the air holes 36, and the electrical components of the electrical substrate 31, etc. This prevents the temperature rise of the electrical components by preventing the temperature rise.

As described above, according to the conventional technology, the exhaust blade is attached to the flywheel that prevents the rotation unevenness of the photosensitive member, and the exhaust heat is exhausted by providing the exhaust air hole in the housing corresponding to the blower blade. Unlike the installation of a dedicated cooling fan, the space for installing the cooling fan, the cost of the cooling fan itself, and the installation cost are not required, and temperature destruction of the electrical parts of the expensive electric board can be prevented at low cost. Then, there is no rotation unevenness of the photosensitive drum, and therefore a high-quality image having no unevenness in the image can be stably obtained.
Japanese Patent Application Laid-Open No. 06-332281

  However, the flywheel for preventing the rotation unevenness of the photosensitive drum requires weight in order to perform its function, and thus has the disadvantage that the weight of the product increases and the cost increases.

  Also, if the flywheel has a wing shape, it is difficult to balance the rotation by processing the wing shape, and the original effect of preventing rotation unevenness cannot be obtained. .

  Furthermore, as image forming apparatuses are printing at higher speeds and resolutions are increasing, tandem systems that print four colors at a time are the mainstream in image forming apparatuses, and the number of photosensitive drums has increased to four for each color. Therefore, it is not preferable in terms of weight to attach a flywheel.

  Here, in recent years, there is an image forming apparatus using a developing unit that frictionally charges toner for high-speed printing. In this image forming apparatus, the rotation of the developing roller inside the developing device increases, and self-heating occurs due to the friction. If this self-heating cannot be exhausted well, the temperature inside the machine rises significantly. If the toner melting point temperature is exceeded, the toner melts and adheres to the developing roller and the developing blade for layer thickness formation in the developing unit, and white is printed. It causes streaks and black streaks. On the contrary, if the melting point temperature of the toner is set high so that the toner does not adhere, the fixing temperature becomes high, resulting in an image forming apparatus with high power consumption or an image forming apparatus in which printing is faint because the fixing property is weak. End up. Further, in a small tandem image forming apparatus, when heat accumulates in the lower part of the exposure apparatus, the optical lens, the reflecting mirror, and the housing are thermally expanded, and the position of the beam to be written is changed, resulting in color misregistration.

  SUMMARY An advantage of some aspects of the invention is that it provides an optical scanning device capable of suppressing temperature rise in the apparatus and an image forming apparatus using the same.

  In order to solve this problem, the optical operation device of the present invention scans each exposure light emitted from a plurality of light sources with respect to a single deflector and scans it through a single optical system. An optical scanning device that forms a latent electrostatic image on each photoconductor by separately irradiating a plurality of photoconductors arranged at equal intervals in the sub-scanning direction. It is a surface that does not have.

  In a preferred embodiment of the present invention, a reinforcing member is provided on the inner bottom surface of the casing of the optical scanning device.

  In a further preferred aspect of the present invention, the lower part of the housing of the optical scanning device has a tapered surface that extends upward in the direction perpendicular to the optical axis.

  In a further preferred aspect of the present invention, the lower part of the housing of the optical scanning device has a tapered surface with the optical axis center as the lowest part.

  In a further preferred aspect of the present invention, the tapered surface has a plurality of inclination angles.

  In a further preferred aspect of the present invention, the optical scanning device is formed with a notch groove in which the end surface of the final optical lens on the scanned body side is open.

  The image forming apparatus of the present invention uses an optical scanning device.

  According to the present invention, since frictional heat does not accumulate in the lower part of the optical scanning device, it is received on both sides of the optical scanning device and guided upward, and then exhausted by natural convection. The effective effect that it becomes possible to suppress the temperature rise of this is acquired.

  In addition, according to the present invention, the strength of the casing is increased, and the relative positional accuracy between the exposure light and the photoconductor is ensured. Therefore, an effective effect of improving the reliability with respect to torsion and expansion accompanying a temperature rise Is obtained.

  Furthermore, according to the present invention, the frictional heat that reaches the lower part of the optical scanning device flows upward smoothly along the tapered surface, so that the exhaust efficiency is improved and the increase in the in-machine temperature is more effectively suppressed. An effective effect is obtained.

  Furthermore, according to the present invention, since the temperature rise distribution of the optical scanning device is made uniform, an effective effect of suppressing the relative positional deviation between the exposure light and the photoconductor can be obtained.

  Furthermore, according to the present invention, it is possible to obtain an effective effect that the exhaust heat efficiency can be improved even if there is no space on the side of the optical scanning device.

  And according to this invention, the effective effect that it is suppressed that heat accumulates in the end surface of the last optical lens and an optical beam shifts | deviates is acquired.

  According to the first aspect of the present invention, each exposure light emitted from a plurality of light sources is incident and deflected to a single deflector, transmitted through a single optical system, and then transmitted in the sub-scanning direction. An optical scanning device that separately irradiates a plurality of photoconductors arranged at equal intervals to form an electrostatic latent image on each photoconductor, and the lower portion of the housing of the optical scanning device is a surface having no unevenness. This is an optical scanning device that does not collect frictional heat in the lower part of the optical scanning device, but is discharged to both sides of the optical scanning device and guided upward, and then exhausted by natural convection. It has the effect that it is possible to suppress temperature rise in the machine.

  The invention according to claim 2 of the present invention is the optical scanning device according to claim 1, wherein a reinforcing member is provided on the inner bottom surface of the housing of the optical scanning device, and the strength of the housing is increased. Thus, since the relative positional accuracy between the exposure light and the photosensitive member is ensured, there is an effect that the reliability with respect to torsion and expansion accompanying temperature rise is improved.

  The invention according to claim 3 of the present invention is the invention according to claim 1 or 2, wherein at least a part of the lower portion of the housing of the optical scanning device has a tapered surface extending upward in the direction perpendicular to the optical axis. Since the frictional heat that has reached the lower part of the optical scanning device smoothly flows upward along the tapered surface, the exhaust efficiency is improved and the increase in the in-machine temperature is more effectively suppressed. It has the action.

  The invention according to claim 4 of the present invention is the optical scanning device according to claim 3, wherein the lower portion of the casing of the optical scanning device is a tapered surface with the optical axis center at the bottom. Since the temperature rise distribution of the scanning device is made uniform, the relative positional deviation between the exposure light and the photoconductor is suppressed.

  According to a fifth aspect of the present invention, in the invention according to the third or fourth aspect, the tapered surface is an optical scanning device having a plurality of inclination angles, and is spatially located laterally of the optical scanning device. Even if there is no allowance, the heat exhaust efficiency can be improved.

  According to a sixth aspect of the present invention, in the optical scanning device according to any one of the third to fifth aspects, a notch groove in which the end surface of the last optical lens on the scanned body side is opened is formed. The optical scanning device has an effect of suppressing the accumulation of heat on the end surface of the final optical lens and the deviation of the optical beam.

  The invention according to claim 7 of the present invention is an image forming apparatus in which the optical scanning device according to any one of claims 1 to 6 is used, and the temperature rise in the apparatus is suppressed, which is favorable. It has the effect that an image of print quality can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described more specifically with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. In addition, since description here is the best form by which this invention is implemented, this invention is not limited to the said form.

(Embodiment 1)
1 is a cross-sectional view showing a tandem color image forming apparatus according to Embodiment 1 of the present invention, FIG. 2 is an explanatory view showing an optical scanning device used in the image forming apparatus of FIG. 1, and FIG. 4 is a perspective view showing an optical scanning device according to the first embodiment, FIG. 4 is a sectional view showing the optical scanning device according to the first embodiment of the present invention, and FIG. 5 is a sectional view showing an optical scanning device as a modification of the present invention. 6 is a perspective view showing an optical scanning device as another modification of the present invention, FIG. 7 is a sectional view showing an optical scanning device as another modification of the present invention, and FIG. 8 is still another embodiment of the present invention. FIG. 9 is a sectional view showing an optical scanning device as still another modification of the present invention, and FIG. 10 is an optical scanning device as still another modification of the present invention. FIG. 11 is a final view of an optical scanning device as still another modification of the present invention. 12 is a perspective view showing a conventional optical scanning device, FIG. 13 is a cross-sectional view showing a conventional optical scanning device, and FIG. 14 is a perspective view showing a final lens in the conventional optical scanning device. It is.

  Referring to FIG. 1, four image forming stations 1a, 1b, 1c, and 1d are arranged in a tandem color image forming apparatus. Each of the image forming stations 1a, 1b, 1c, and 1d has a photoconductor 2a and an image carrier. 2b, 2c, and 2d, and around them, dedicated charging means 3a, 3b, 3c, and 3d for charging the periphery of the photoreceptors 2a, 2b, 2c, and 2d to a uniform potential, and the photoreceptors 2a and 2b , 2c, 2d, developing means 4a, 4b, 4c, 4d for visualizing the electrostatic latent images, and cleaning means 5a for cleaning the surfaces of the photoreceptors 2a, 2b, 2c, 2d after the toner image transfer, 5b, 5c, 5d, an optical scanning device 6 which is an exposure means for irradiating each photoconductor 2a, 2b, 2c, 2d with a laser beam (exposure light) according to image information, and photoconductors 2a, 2b, 2c. , 2 The endless intermediate transfer belt 12 provided so as to be in contact with the intermediate transfer belt 12 and the intermediate transfer belt 12 are pressed against the photoconductors 2a, 2b, 2c, and 2d to form toner images formed on the photoconductors 2a, 2b, 2c, and 2d. Transfer devices 8a, 8b, 8c, and 8d for transferring to the intermediate transfer belt 12 are disposed. The transfer means 7 is constituted by the intermediate transfer belt 12, the support rollers 10 and 11 for rotating the intermediate transfer belt 12 (rotating in the direction of arrow A), and the transfer devices 8a, 8b, 8c and 8d. In addition, the optical scanning device 6 formed of a metal or resin casing is supported by a frame 29 disposed above the image forming stations 1a, 1b, 1c, and 1d.

  FIG. 2 is an explanatory view of the optical scanning device 6 used in the image forming apparatus of FIG. 1, and each laser beam emitted from a plurality of light sources is used so that laser beam spatial separation after passing through the lens is advantageous. The light is incident in parallel with the deflection plane of the single deflector 22 in the vertical direction. A first fθ lens 24, a second fθ lens 25, and a third fθ lens 26 are sequentially disposed on the optical path from the deflector 22 to the photoreceptors 2a, 2b, 2c, and 2d, and further, the second fθ lens 25 and the third fθ lens. 26, reflection mirrors 23a, 23b, 23c, 23d, 23e, 23f, and 23g are appropriately disposed.

  Here, the image forming stations 1a, 1b, 1c, and 1d form a yellow image, a magenta image, a cyan image, and a black image, respectively. From the optical scanning device 6, the yellow image, the magenta image, the cyan image, and the black image are formed. Corresponding laser beams 9a, 9b, 9c, 9d are output.

  Opposite to the intermediate transfer belt 12, a toner density detecting means 14 for detecting the toner density of the test pattern from the test pattern generating means 13 is arranged. The toner density detecting means 14 detects the density of the test pattern generated by the test pattern generating means 13 immediately after the power is turned on or at regular intervals. The exposure intensity correction unit 15 determines the exposure power of each color based on the detection result from the toner density detection unit 14, and the development bias correction unit 16 corrects the development bias value of each color. The optical scanning device 6 outputs the determined exposure intensity from the exposure intensity correcting means 15, and the developing means 4 a, 4 b, 4 c, 4 d apply the developing bias according to the correction value from the developing bias correcting means 16.

  The sheet material 18 stored in the sheet feeding cassette 17 is fed by a sheet feeding roller 19 and is discharged to a sheet discharge tray (not shown) through a sheet material transfer roller 20 and a fixing unit 21.

  In the configuration described above, first, a latent image of the black component color of the image data is formed on the photoreceptor 2d by the electrophotographic process means such as the charging means 3d and the optical scanning device 6 of the image forming station 1d, and then the developing means 4d. Then, a black toner image is visualized as a black toner image by a developer having black toner, and the black toner image is transferred to the intermediate transfer belt 12 by the transfer device 8d.

  On the other hand, while the black toner image is transferred to the intermediate transfer belt 12, a cyan component color latent image is formed at the image forming station 1c, and a cyan toner image is obtained by the developing means 4c, and this is transferred to the transfer unit 8c. And is superposed on the black toner image previously transferred onto the intermediate transfer belt 12.

  Thereafter, image formation is similarly performed for the magenta toner image and the yellow toner image, and when the four color toner images are superimposed on the intermediate transfer belt 12, the paper is fed from the paper feed cassette 17 by the paper feed roller 19. The four color toner images are collectively transferred and conveyed onto the sheet material 18 such as paper by the sheet material transfer roller 20 and heated and fixed by the fixing means 21, and a full color image is obtained on the sheet material 18.

  The photosensitive members 2a, 2b, 2c, and 2d that have been transferred have their residual toner removed by the cleaning means 5a, 5b, 5c, and 5d, and are prepared for the next subsequent image formation, thereby completing the printing operation. .

  When such a printing operation is repeated, each image forming station 1a, 1b, 1c, 1d is continuously charged by friction between each color toner and each developing means 4a, 4b, 4c, 4d. The toner is given a positive or negative charge. This charge causes the toner to move to the photoreceptors 2a, 2b, 2c, and 2d, but heat is generated due to friction as a by-product.

  As shown in FIG. 1, the frame 29 that supports the optical scanning device 6 is configured so that the image forming station 1a is not affected by the fixing unit 21 that is the largest heat source in the image forming apparatus, and the image information is included in the image information. Holes for irradiating the corresponding photoconductors 2a, 2b, 2c, and 2d with corresponding laser beams are formed.

  Here, the frictional heat generated as a by-product passes through this hole or another hole provided for exhaust, and reaches the lower part of the optical scanning device 6. In the conventional optical scanning device 6, FIGS. As shown, since the reinforcing rib 6a of the housing is provided at the lower portion so as to partition, friction heat is accumulated inside the reinforcing rib 6a, and there is no escape space for heat, so that the center of the image forming apparatus is A temperature rise was caused in the vicinity, and as a result, the toner was fixed to the developing means, resulting in poor printing. In addition, since frictional heat accumulates in the lower part of the optical scanning device 6, thermal expansion occurs in the casing, and if the thermal expansion does not occur uniformly with respect to the casing, the optical scanning position shifts and color misregistration occurs in printing. It became a malfunction.

  Therefore, in the present application, the frictional heat accumulated in the lower part of the optical scanning device 6 is flowed to the upper part and is exhausted along the shape of the paper discharge tray as shown by the arrow E in FIG. 1 (details will be described later). ). As a result, the warm air inside the machine gathers inside the upper discharge tray, and the spatial distance between the highest temperature part in the machine and the optical scanning device and each image forming station is sufficiently maintained, so that the printing failure is caused. If the outside air is introduced from the paper feed cassette at the bottom of the image forming apparatus, there is no need to add a blower fan or the like due to the chimney effect. Temperature rise can be prevented.

  Specific examples of such a structure are shown in FIGS. As shown in the drawing, the rib for reinforcing the lower part of the optical scanning device 6 is eliminated, and the bottom surface of the housing is made a surface having no unevenness. With this shape, the frictional heat that reaches the lower part of the optical scanning device 6 is not collected in the lower part of the optical scanning device, but is carried to both sides of the optical scanning device 6 and guided to the lower part of the uppermost discharge tray. Since heat is exhausted by natural convection along the inside of the paper discharge tray, the exhaust efficiency is improved, and an increase in the in-machine temperature can be reliably suppressed at low cost without adding a fan or the like.

  FIG. 5 shows a modified example in which reinforcing ribs (reinforcing members) 6a are provided in an inner bottom surface of the optical scanning device 6 in a rectangular shape or a lattice shape in order to ensure the housing strength of the optical scanning device 6. Further, the reliability with respect to the optical writing position is improved. That is, in the tandem type image forming apparatus, the relative positional relationship of the laser beam written on the photoreceptors 2a, 2b, 2c, and 2d of the image forming stations 1a, 1b, 1c, and 1d, for example, scanning tilt, curvature, and writing position. If the above changes during printing, color deviation occurs as a printing result, which is not preferable because printing quality deteriorates. For this reason, the reinforcing rib 6a is provided on the inner bottom surface in order to ensure the positional accuracy, thereby improving the strength of the housing, thereby preventing the optical system from being deformed by twisting and expansion accompanying a temperature rise, and Improved.

  FIGS. 6 and 7 are other modifications, in which the unevenness of the bottom surface of the housing of the optical scanning device 6 is eliminated, the center of the optical axis is the lowermost portion, and the tapered shape extends upward in the direction perpendicular to the optical axis. A groove (tapered surface) is provided linearly or curvedly. As a result, the frictional heat reaching the lower part of the optical scanning device 6 smoothly flows upward along the taper surface and is guided to the lower part of the paper discharge tray, so that the exhaust efficiency is improved and the temperature inside the apparatus is more effectively increased. To be suppressed.

  In addition, including the case described below, the bottom surface itself may be tapered instead of forming such a groove on the bottom surface. That is, it is sufficient that at least a part of the bottom surface is tapered.

  Moreover, the optical axis center does not necessarily have to be the lowest part. However, if the center of the optical axis is at the bottom, the temperature rise distribution of the housing of the optical scanning device 6 is made uniform, and the relative positional deviation between the laser beam and the photosensitive members 2a, 2b, 2c, 2d is shifted. It is suppressed.

  FIGS. 8 and 9 show still another modification example, in which unevenness on the bottom surface of the housing of the optical scanning device 6 is eliminated, and a tapered groove with the optical axis center at the bottom is linearly or curvedly provided. Further, the groove is bent upward and the inclination angle is changed. That is, there are a plurality of inclination angles. As a result, in a smaller tandem image forming apparatus, the optical scanning device 6 is disposed so as to be wrapped along the optical axis direction in order to ensure the strength of the main body frame 29, and thus the frame 29 and the optical scanning device 6 are arranged. This is effective when the gap is small and it is difficult to secure a space through which frictional heat passes on both sides of the optical scanning device 6. That is, if this shape is used, a space between the frame 29 and the side surface of the optical scanning device 6 can be secured, so that frictional heat can be applied to both sides of the optical scanning device 6 and guided to the lower portion of the paper discharge tray. As a result, the exhaust efficiency is improved and the rise in the in-machine temperature can be further suppressed.

  In the case shown in the figure, the inclination angle of the tapered surface that is the groove changes once (that is, has two inclination angles), but may change more than once.

  10 and 11 show still another modification. As shown in FIG. 14, in the conventional final lens on the scanned body side, there is a rib on the end surface on the scanning direction side, so that frictional heat accumulates in this portion, and the toner scattered by the frictional heat, particularly frictional The floating charged toner finely pulverized by charging is attracted to the lens and causes a problem in the printing result. Therefore, as shown in FIGS. 10 and 11, a part of the end face of the final optical lens is made concave, and a part of the end of the part where the final lens is supported by the housing of the optical scanning device 6 is cut. By forming a notch groove with an open end face, frictional heat and floating charged toner can be received on both sides of the optical scanning device 6 and guided to the lower part of the paper discharge tray, so that the exhaust efficiency is improved and the in-machine temperature is reduced. The rise can be further suppressed.

  The present invention can be widely applied to an optical scanning device and an image forming apparatus in which the optical scanning device is used. For example, the present invention can be applied to an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction printer.

Sectional drawing which shows the color image forming apparatus of the tandem system in Embodiment 1 of this invention Explanatory drawing which shows the optical scanning device used for the image forming apparatus of FIG. 1 is a perspective view showing an optical scanning device according to a first embodiment of the present invention. Sectional drawing which shows the optical scanning device which is Embodiment 1 of this invention Sectional drawing which shows the optical scanning device as a modification of this invention The perspective view which shows the optical scanning device as another modification of this invention Sectional drawing which shows the optical scanning device as another modification of this invention The perspective view which shows the optical scanning device as another modification of this invention. Sectional drawing which shows the optical scanning device as another modification of this invention The perspective view which shows the optical scanning device as another modification of this invention. The perspective view which shows the principal part of the last lens in the optical scanning device as another modification of this invention. A perspective view showing a conventional optical scanning device Sectional view showing a conventional optical scanning device The perspective view which shows the last lens in the conventional optical scanning device Sectional drawing which shows the back side containing the photoreceptor in the conventional image forming apparatus

Explanation of symbols

1a, 1b, 1c, 1d Image forming stations 2a, 2b, 2c, 2d Photoconductors 3a, 3b, 3c, 3d Charging means 4a, 4b, 4c, 4d Developing means 5a, 5b, 5c, 5d Cleaning means 6 Optical scanning device 7 Transfer means 8a, 8b, 8c, 8d Transfer device 9a, 9b, 9c, 9d Laser beam 10, 11 Support roller 12 Intermediate transfer belt 13 Test pattern generation means 14 Toner density detection means 15 Exposure intensity correction means 16 Development bias correction means DESCRIPTION OF SYMBOLS 17 Paper feed cassette 18 Sheet material 19 Paper feed roller 20 Sheet material transfer roller 21 Fixing means 22 Deflector 23 Reflection mirror 24 1st f (theta) lens 25 2nd f (theta) lens 26 3rd f (theta) lens 27 Image forming apparatus 28 Case 1
29 Case 2
30 Bearing 31 Electric board 32 Flywheel 33 鋲 34 Mounting member 35 Blower blade 36 Air hole 37 Axis

Claims (7)

Each exposure light emitted from a plurality of light sources is incident and deflected on a single deflector, transmitted through a single optical system, and then separated into a plurality of photoconductors arranged at equal intervals in the sub-scanning direction. An optical scanning device that irradiates and forms an electrostatic latent image on each photoconductor,
The lower part of the housing of the optical scanning device is a surface having no irregularities. The optical scanning device according to claim 1, wherein a reinforcing member is provided on an inner bottom surface of the housing of the optical scanning device. 3. The optical scanning device according to claim 1, wherein at least a part of the lower portion of the housing of the optical scanning device has a tapered surface extending upward in the direction perpendicular to the optical axis. 4. The optical scanning device according to claim 3, wherein the lower portion of the housing of the optical scanning device has a tapered surface with the center of the optical axis at the bottom. The optical scanning device according to claim 3, wherein the tapered surface has a plurality of inclination angles. The optical scanning device according to any one of claims 3 to 5, wherein the optical scanning device is formed with a notch groove in which an end surface of the final optical lens on the scanned body side is opened. An image forming apparatus using the optical scanning device according to claim 1.

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