Image forming device

Abstract

To prevent the occurrence of a reduction in image quality due to pressing on an optical box.SOLUTION: An image forming apparatus 1 comprises: an optical scanner 2 having a semiconductor laser, a deflector 7 that includes a rotary polygon mirror 4 for deflecting and scanning a laser beam emitted from the semiconductor laser, an optical box 3 that includes imaging lenses 8, 9 for forming the deflected and scanned laser beam into an image, and a lid member 5 that covers the optical box 3; and photoconductor drums 11 that carry toner images. The image forming apparatus 1 has a cartridge tray 40 that is movable to the outside of the image forming apparatus. The cartridge tray 40 and the optical scanner 2 are arranged opposite to each other. The lid member 5 is arranged in contact with a space generated when the cartridge tray 40 is moved to the outside of the image forming apparatus 1.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus, such as a copying machine or a printer, that is equipped with an optical scanning device. [Background technology]

[0002] Conventionally, an image forming apparatus for forming a color image irradiates laser light from a plurality of light sources of an optical scanning device onto a corresponding photosensitive drum to form an electrostatic latent image, and forms a color image by superimposing a toner image visualized by a plurality of toners. Each process cartridge corresponding to a plurality of color toners is integrated with process means such as a photosensitive drum, a charging means, and a developing means, and is detachably disposed in the image forming apparatus main body. In addition, the image forming apparatus is provided with a paper feed cassette that contains recording material for forming a toner image, and is configured such that when the remaining amount of recording material becomes low, the paper feed cassette is pulled out from the image forming apparatus main body, refilled with recording material, and then stored back in the image forming apparatus main body.

[0003] For example, Patent Document 1 describes a configuration in which a tray that supports a plurality of arranged process cartridges, called an in-line system, is provided inside the image forming apparatus, and the tray is pulled out to the outside of the image forming apparatus when replacing the process cartridges.Also, for example, Patent Document 2 describes an image forming apparatus that includes a paper feed cassette for storing recording materials inside the image forming apparatus, and the paper feed cassette is pulled out to the outside of the image forming apparatus to replenish recording materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-003413 A [Patent Document 2] JP 2017-90769 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the image forming apparatus described in Patent Document 1, when the tray on which the process cartridge is placed is pulled out to the outside of the image forming apparatus, an empty space is generated where the process cartridge was placed. Then, a person can insert his / her hand into the empty space, and the person's hand can directly touch the optical box of the optical scanning device arranged adjacent to the empty space. Also, in the image forming apparatus described in Patent Document 2, a person can insert his / her hand into the empty space generated when the paper feed cassette is pulled out to the outside of the image forming apparatus. Since there is a partition between the paper feed cassette and the optical scanning device, the person's hand cannot directly touch the optical box of the optical scanning device, but for example, if the partition is removed to reduce the size of the image forming apparatus, the person's hand can directly touch the optical box.

[0006] In the configuration of Patent Document 1 and the configuration of Patent Document 2 in which the partition is removed, if a human hand touches and presses the optical box, there is a concern that the optical box will be deformed by the applied stress. When stress is applied to the optical box, the posture of optical components such as lenses and folding mirrors arranged inside the optical box will change. As a result, the irradiation position of the laser light emitted from the optical scanning device on the photosensitive drum will change, and there is a concern that the desired image quality will not be obtained for the formed image. In addition, the optical box and the like may become charged when a human hand touches the optical scanning device. As a result, electrostatic discharge (ESD) may occur in ICs such as the laser driver, motor driver, and BD sensor inside the optical scanning device, which may damage the ICs.

[0007] The present invention has been made under these circumstances, and an object of the present invention is to prevent deterioration of image quality caused by pressing the optical box. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention has the following configuration.

[0009] (1) An image forming apparatus including an optical scanning device having a light source, a deflector having a rotating polygonal mirror for deflecting and scanning a laser beam emitted from the light source, an imaging lens for imaging the deflected and scanned laser beam, an optical box for holding the light source, the deflector, and the imaging lens, and a lid member for covering an opening of the optical box, an image carrier having an electrostatic latent image formed on a surface thereof by being scanned with the laser beam emitted from the optical scanning device, and a developing means for supplying toner to the image carrier to develop the electrostatic latent image, the image forming apparatus having a moving unit movable to the outside of the image forming apparatus, the moving unit and the optical scanning device are disposed opposite to each other when the moving unit is housed inside the image forming apparatus, no partition is provided between the optical scanning device and the moving unit, and the optical scanning device is disposed so that the lid member is exposed to a space generated when the moving unit is moved to the outside of the image forming apparatus, The optical box is provided with a backup section having a clearance with respect to the lid member that is smaller than the clearance with respect to the optical components including the imaging lens, and even if a user inserts his / her hand into the space and pushes the lid member with his / her hand, causing the lid member to bend, the lid member is supported by contact with the backup section, thereby preventing the lid member from coming into contact with the optical components. An image forming apparatus comprising: Effect of the Invention

[0010] According to the present invention, it is possible to prevent deterioration of image quality caused by pressing the optical box. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a configuration of an image forming apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic cross-sectional view showing a configuration of an optical scanning device according to a first embodiment. [Diagram 3] FIG. 1 is a diagram for explaining replacement of a process cartridge according to the first embodiment; [Figure 4] FIG. 1 is a diagram for explaining replacement of a process cartridge according to the first embodiment; [Diagram 5] FIG. 1 is a diagram for explaining replacement of a process cartridge according to the first embodiment; [Figure 6] FIG. 1 is a diagram for explaining replacement of a process cartridge according to the first embodiment; [Figure 7] FIG. 1 is a diagram for explaining a method for fixing a cover member of the optical scanning device according to the first embodiment. [Figure 8]FIG. 1 is a diagram for explaining deformation of a cover member of the optical scanning device according to the first embodiment; [Figure 9] FIG. 11 is a schematic cross-sectional view showing a configuration of an image forming apparatus according to a second embodiment of the present invention. [Figure 10] FIG. 13 is a diagram showing a configuration of an optical scanning device according to a second embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view showing the configuration of an optical scanning device according to a second embodiment. [Figure 12] FIG. 11 is a diagram illustrating a state in which the paper feed cassette is pulled out according to the second embodiment. [Figure 13] FIG. 11 is a diagram for explaining a method for fixing a cover member of an optical scanning device according to a second embodiment. [Figure 14] FIG. 13 is a diagram for explaining deformation of a cover member of the optical scanning device according to the second embodiment. [Figure 15] FIG. 13 is a diagram illustrating a cover member of the optical scanning device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0013] [Image forming equipment] FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus 1 of the first embodiment, and the image forming apparatus 1 has a configuration in which an optical scanning device 2 and process cartridges PY, PM, PC, and PK are attached to a main body. The image forming apparatus 1 of this embodiment forms a full-color image by superimposing toner images visualized with four colors of toner, namely, yellow (Y), magenta (M), cyan (C), and black (K). As shown in FIG. 1, the process cartridges PY, PM, PC, and PK have the same configuration, and the suffixes a, b, c, and d of the reference numerals of the members of each process cartridge indicate that they are the members of the process cartridges PY, PM, PC, and PK, respectively. In the following description, the suffixes a, b, c, and d of the reference numerals are omitted except when referring to a member of a specific process cartridge.

[0014] In addition, in the first embodiment, the side of the image forming apparatus 1 where a door 41, which will be described later, is provided is referred to as the "front" side of the image forming apparatus 1, and the side opposite the door 41 is referred to as the "rear" side of the image forming apparatus 1. Furthermore, the right side when looking at the "rear" side of the image forming apparatus 1 from the "front" side is referred to as the "right", and the left side when looking at the "rear" side of the image forming apparatus 1 from the "front" side is referred to as the "left".

[0015] The configuration of the image forming apparatus 1 and the image forming process will be described with reference to FIG. 1. The optical scanning device 2 is disposed vertically above the process cartridges PY, PM, PC, and PK, and irradiates the photosensitive drum 11, which is an image carrier that carries the toner image of the process cartridges PY, PM, PC, and PK, with laser beams L1, L2, L3, and L4 according to image data. The photosensitive drum 11 of each process cartridge is charged to a uniform potential in advance by a charging roller 12, and an electrostatic latent image is formed on the surface of the photosensitive drum 11 by discharging the charge only in the portion irradiated with the laser beam from the optical scanning device 2. Toner is attached to the electrostatic latent image on each photosensitive drum 11 by each developing roller 13, and a toner image is formed. A primary transfer roller 22 is disposed at a position facing each photosensitive drum 11, and a transfer voltage is applied to the primary transfer roller 22, so that the toner images on each photosensitive drum 11 are transferred to the intermediate transfer belt 21 in a superimposed manner in sequence.

[0016] On the other hand, the recording material S, which is a recording medium placed in a paper feed cassette 31 arranged vertically below the intermediate transfer belt 21, is fed from the paper feed cassette 31 by a pickup roller 32 in synchronization with the image forming process of the process cartridge described above. The recording material S fed from the paper feed cassette 31, which is a stacking section, is conveyed to a secondary transfer roller 33, which transfers the four-color toner image transferred onto the intermediate transfer belt 21 onto the recording material S. The recording material S onto which the toner image has been transferred is conveyed to a fixing device 34, where the toner image is fixed to the recording material S by applying heat and pressure. Thereafter, the recording material S that has passed through the fixing device 34 is discharged to an external discharge tray 37 by discharge rollers 35 and 36.

[0017] [Optical scanning device] 2 is a schematic cross-sectional view showing the configuration of an optical scanning device 2 that exposes a photosensitive drum 11, which is a photosensitive body shown in FIG. 1. The optical scanning device 2 deflects each laser light (light beam) L1, L2, L3, and L4 emitted from a semiconductor laser (not shown) that is a plurality of light sources by a rotary polygon mirror 4 of a deflector 7, and irradiates the corresponding photosensitive drums 11a, 11b, 11c, and 11d through optical members. The optical scanning device 2 has a deflector 7 having a rotary polygon mirror 4, first imaging lenses 8a and 8b that are imaging members of the laser light, second imaging lenses 9a to 9d, folding mirrors 10a to 10f that are reflecting members, and an optical box 3 in which these members are arranged. Furthermore, in order to seal the optical box 3, it has a cover member 5 that closes (covers) the opening of the optical box 3.

[0018] 2, a backup section 6, which is a rib section, is provided near the optical components (optical system) inside the optical box 3. The backup section 6 stands from a structural member, a supporting member, or a bottom surface inside the optical box 3 in the direction of the lid member 5, and has a length such that a clearance (distance) between the tip end in the direction of the lid member 5 and the lid member 5 is about 1 mm. Therefore, it is possible to prevent direct contact between the lid member 5 and an optical component (e.g., the second imaging lens 9, etc.) inside the optical scanning device 2, which is arranged with a clearance larger than the clearance between the tip end of the backup section 6 and the lid member 5.

[0019] The optical box 3 is disposed vertically above the process cartridges PY, PM, PC, and PK, and the cover member 5 is disposed vertically below the optical box 3. That is, the cover member 5 is disposed on the side facing the process cartridges PY, PM, PC, and PK. In addition, the deflector 7 has a drive substrate 7a for driving and rotating the rotating polygon mirror 4 fixed to the bottom surface of the optical box 3, and the rotating polygon mirror 4 is disposed vertically below the drive substrate 7a.

[0020] Next, the operation of the optical scanning device 2 will be described. Laser beams L1, L2, L3, and L4 emitted from a plurality of semiconductor lasers (not shown) pass through a plurality of lenses (not shown), are incident on a rotating polygon mirror 4 at an angle with respect to a scanning plane D, and are deflected (deflection scanning) by the rotating polygon mirror 4. The laser beam L1 deflected by the rotating polygon mirror 4 passes through a first imaging lens 8a, and then has its optical path deflected by a folding mirror 10c corresponding to the process cartridge PY. The laser beam L1 then passes through a second imaging lens 9a and an opening of a cover member 5, and scans the surface of the photosensitive drum 11a of the corresponding process cartridge PY at a constant speed while forming a spot on the photosensitive drum 11a.

[0021] The laser beam L2 deflected by the rotating polygon mirror 4 passes through a first imaging lens 8a, and then has its optical path deflected by folding mirrors 10a and 10b corresponding to the process cartridge PM. The laser beam L2 then passes through a second imaging lens 9b and the opening of the cover member 5, and scans the surface of the photosensitive drum 11b of the corresponding process cartridge PM at a constant speed while forming a spot on the photosensitive drum 11b.

[0022] The laser beam L3 deflected by the rotating polygon mirror 4 passes through the first imaging lens 8b, and then has its optical path deflected by the folding mirror 10d corresponding to the process cartridge PC. The laser beam L3 then passes through the second imaging lens 9c, the folding mirror 10e, and the opening of the cover member 5, and scans the surface of the photosensitive drum 11c of the corresponding process cartridge PC at a constant speed while forming a spot on the photosensitive drum 11c.

[0023] The laser beam L4 deflected by the rotating polygon mirror 4 passes through the first imaging lens 8b, and then the optical path is deflected by the folding mirror 10f corresponding to the process cartridge PK. The laser beam L4 then passes through the second imaging lens 9d and the opening of the cover member 5, and scans the surface of the photosensitive drum 11d of the corresponding process cartridge PK at a constant speed while forming a spot on the photosensitive drum 11d.

[0024] [Replacing the process cartridge] 3 to 6 are diagrams illustrating a method for replacing a process cartridge in the image forming apparatus 1. In each of the process cartridges PY, PM, PC, and PK, the toner (developer) contained in the developing device 14 is consumed as the cartridge is used for image formation. When the toner is consumed and image formation is no longer possible, the process cartridge from which the toner has run out is replaced with a new process cartridge. The process cartridges PY, PM, PC, and PK in this embodiment are placed on a cartridge tray 40 (moving unit) of a drawer type. Therefore, the process cartridge is replaced by pulling out the cartridge tray 40 from the image forming apparatus 1, replacing the corresponding process cartridge, and then storing the cartridge tray 40 back into the image forming apparatus 1.

[0025] [Image forming device door] FIG. 3 is a schematic cross-sectional view of the image forming apparatus 1 for explaining a maintenance door 41 of the image forming apparatus, and FIG. 3 shows the door 41 in an open state. The door 41 has a grip 41a (finger hook) at one end for opening and closing the door 41, and the other end is rotatable about a horizontal shaft 42. As shown in FIG. 3, the door 41 is opened and closed when the cartridge tray 40 is pulled out or when the cartridge tray 40 is stored inside the image forming apparatus 1. Note that FIG. 1 shows both the closed and open states of the door 41. When the door 41 is opened, an opening 50 is created through which the cartridge tray 40 passes.

[0026] FIG. 4 is a perspective view showing a state in which the door 41 is opened and the cartridge tray 40 is housed in the image forming apparatus 1. Meanwhile, FIG. 5 is a perspective view showing a state in which the door 41 is opened and the cartridge tray 40 is pulled out from the image forming apparatus 1. As shown in FIG. 4, the door 41 has a horizontal shaft 42 as a hinge passing through the left and right sides in the figure, and is rotatable about the horizontal shaft 42 with respect to the image forming apparatus 1. That is, the door 41 can be rotated so as to stand upright in the upward direction in the figure about the horizontal shaft 42 to close the opening 50 of the image forming apparatus 1. Meanwhile, the opening 50 can be opened by rotating the door 41 so as to fall down toward the front side (lower right side in the figure) of the image forming apparatus 1 about the horizontal shaft 42. A pair of left and right tray holding members 61L and 61R for holding the cartridge tray 40 are disposed inside the left frame 60L and inside the right frame 60R that form the frame of the image forming apparatus 1. The tray holding members 61L and 61R are provided facing each other, and the cartridge tray 40, which is a frame-shaped member, is sandwiched between the tray holding members 61L and 61R. As shown in Fig. 5, the cartridge tray 40 is sandwiched between the tray holding members 61L and 61R and is therefore movable in the front-rear direction along the tray holding members 61L and 61R. In this manner, the process cartridges PY, PM, PC, and PK are placed and supported on the cartridge tray 40, and each process cartridge is individually and removably attached as required.

[0027] 6 is a schematic cross-sectional view showing a state in which the cartridge tray 40 carrying the process cartridges PY, PM, PC, and PK is pulled out to the outside of the image forming apparatus 1 in order to replace the process cartridges. As shown in FIG. 6, the cartridge tray 40 can be moved from the storage position on the tray holding members 61L and 61R to the front direction of the image forming apparatus 1 through the opening 50 by opening the door 41. In FIG. 6, the cartridge tray 40 is in a state in which the process cartridges PY, PM, PC, and PK carried on the cartridge tray 40 are pulled out to the outside of the image forming apparatus 1 (pulled out position). When the cartridge tray 40 is pulled out to the outside of the image forming apparatus 1 by a predetermined amount from the tray holding members 61L and 61R, a stopper portion (not shown) restricts further pulling out movement, and the pulled out position is maintained.

[0028] Then, when the cartridge tray 40 is pulled out from the image forming apparatus 1, the process cartridge is replaced. First, the used process cartridge to be replaced is lifted upward in the figure and removed from the cartridge tray 40. Next, a new process cartridge is placed on the cartridge tray 40 at the position of the removed process cartridge, and attached to the cartridge tray 40. Then, when the replacement of the process cartridge is completed, the cartridge tray 40 is moved from the pulled-out position to the outside of the image forming apparatus 1 to a storage position to store it in the image forming apparatus 1, and when the movement to the storage position is completed, the door 41 is closed. Then, in conjunction with the operation of closing the door 41, the cartridge tray 40 moves from the storage position to a transfer contact position where the photosensitive drum 11 in each process cartridge faces the primary transfer roller 22. In conjunction with the movement of the cartridge tray 40, each process cartridge PY, PM, PC, PK is pressed by a pressing member (not shown) and fixed in a predetermined position. As a result, as shown in FIG. 1, the photosensitive drum 11 of each process cartridge PY, PM, PC, and PK is fixed in a position facing the corresponding primary transfer roller 22, and the toner image on the photosensitive drum 11 comes into contact with the intermediate transfer belt 21, making it possible to form an image.

[0029] Incidentally, when the cartridge tray 40 is pulled out to the outside of the image forming apparatus 1 when replacing the process cartridge, an empty space 51 is generated inside the image forming apparatus 1 at the position where the cartridge tray 40 was stored before being pulled out. Since there is no partition between the optical scanning device 2 and the process cartridges PY, PM, PC, and PK in order to reduce the size, the cover member 5 of the optical scanning device 2 is exposed in the empty space 51. Therefore, a person can insert his / her hand H1 into the empty space 51 through the opening 50 and may accidentally touch the cover member 5 of the optical scanning device 2 and press the cover member 5.

[0030] [Installation of the cover of the optical scanning device] Fig. 7 is a schematic diagram for explaining a method for fixing the cover member 5 to the optical scanning device 2. As shown in Figs. 1 and 2, the optical scanning device 2 is arranged so that the optical box 3 is on the upper side in the vertical direction and the cover member 5 is on the lower side in the vertical direction. Fig. 7 is a perspective view showing the external shape of the optical scanning device 2 when viewed from the cover member 5 side. The four elongated openings provided in the cover member 5 are openings through which the laser beams L1 to L4 shown in Fig. 2 pass.

[0031] The cover member 5 has snap-fit ​​structures 5a, 5b, 5c, and 5d molded integrally with the cover member 5 in order to fix it to the optical box 3. The snap-fit ​​structures 5a, 5b, 5c, and 5d are each shaped like a square with an opening in the center. Meanwhile, protrusions 3a, 3b, 3c, and 3d for fixing the cover member 5 are provided near the four corners of the optical box 3 of the optical scanning device 2.

[0032] When the cover member 5 is attached to the optical box 3, each snap-fit ​​structure 5 elastically bends, so that the cover member 5 passes over each protrusion 3 provided on the optical box 3 corresponding to each snap-fit ​​structure 5, and the protrusion 3 engages with the opening of each snap-fit ​​structure 5. As a result, the protrusions 3a, 3b, 3c, and 3d protrude from the openings of the snap-fit ​​structures 5a, 5b, 5c, and 5d, respectively, and the cover member 5 is fixed to the optical box 3.

[0033] [Deformation of the cover of the optical scanning device] FIG. 8 is a cross-sectional view of the optical scanning device 2 for explaining the deformation of the cover member 5 when a person's hand H1 touches the cover member 5 of the optical scanning device 2. FIG. 8 is a cross-sectional view of the optical scanning device 2 in FIG. 7, taken from a cut surface near where the protrusions 3a and 3b engage with the snap-fit ​​structures 5a and 5b, respectively, in a state where the cover member 5 shown in FIG. 7 is fixed to the optical scanning device 2, as viewed from the rear side to the front side. In FIG. 8, the second imaging lens 9a through which the laser light L1 passes can be seen from the cut surface. In addition, three rib portions standing from the center of the optical box 3 in FIG. 8 toward the cover member 5 are backup portions 6 (6a, 6b, 6c) to be described later.

[0034] As shown in FIG. 8, when replacing a process cartridge, if a hand H1 is inserted from the opening and touches the cover member 5 of the optical scanning device 2, a pressing force P1 of 5 to 20 N is applied to the cover member 5 in the direction of the optical box, based on the pressing force of an average person. When the cover member 5 is bent by the pressing force P1, the snap-fit ​​structures 5a and 5b (snap-fit ​​structures 5c and 5d are not shown in FIG. 8) which are fixing parts provided on the cover member 5 are elastically deformed in the directions of the arrows Ra and Rb in the figure. At the same time, the cover member 5 is deformed from the original position 5' (shown by a dotted line in the figure) in the direction toward the inside of the optical box 3, and comes into contact with the backup part 6 provided on the optical box 3 for restricting the deformation. The backup part 6 is provided near an optical component (for example, the second imaging lens 9a) arranged in the optical box 3. The backup part 6 has a length such that the clearance (distance) between the tip end in the cover member 5 direction and the cover member 5 is about 1 mm. Therefore, it is possible to prevent direct contact between the cover member 5 and optical components inside the optical scanning device 2, which are arranged with a clearance larger than the clearance between the cover member 5 and the backup section 6.

[0035] As described above, even if a person's hand H1 touches the optical scanning device 2 when the cartridge tray 40 is moved outside the image forming apparatus 1 during process cartridge replacement, the position of the optical components does not fluctuate, causing changes in the optical characteristics or degradation in image quality.

[0036] In this embodiment, the backup section 6 for reducing the deflection caused when the human hand H1 contacts the cover member 5 is provided on the optical box 3 side. However, the backup section 6 may be provided on the cover member 5 side as follows. That is, the backup section 6 is provided on the surface of the cover member 5 facing the bottom surface of the optical box 3 where the optical member is disposed or the internal structure, etc., and is provided vertically toward the optical box 3, with a length such that the clearance between the tip of the backup section 6 and the facing surface of the optical box 3 is about 1 mm. As a result, even if the cover member 5 is pressed toward the optical box 3, the backup section 6 provided on the cover member 5 contacts the facing surface of the optical box 3 before the cover member 5 contacts the optical member. This makes it possible to prevent the cover member 5 from coming into direct contact with the optical components inside the optical scanning device 2, which are arranged with a clearance larger than the clearance of the backup section 6.

[0037] As described above, according to this embodiment, it is possible to prevent deterioration of image quality caused by pressing the optical box. EXAMPLES

[0038] In the first embodiment, an example of an image forming apparatus having a configuration in which an optical scanning device is disposed at the vertical upper part of a process cartridge is described. In the second embodiment, an example of an image forming apparatus having an optical scanning device disposed at the vertical lower part of a process cartridge and a paper feed cassette (moving unit) for feeding a recording material disposed at the vertical lower part of the optical scanning device is described.

[0039] [Image forming equipment] FIG. 9 is a schematic cross-sectional view showing the configuration of an image forming apparatus 100 of the second embodiment. The image forming apparatus 100 has a configuration in which an optical scanning device 101 and image forming units of yellow (y), magenta (m), cyan (c), and black (k) are attached to a main body. The image forming apparatus 100 of this embodiment forms a full-color image by superimposing toner images visualized with four colors of toner, yellow (y), magenta (m), cyan (c), and black (k). As shown in FIG. 9, each image forming unit has a different toner color but has the same configuration. In addition, the suffixes y, m, c, and k of the reference numbers of the members of each image forming unit indicate that the members are image forming units with toner colors of yellow (y), magenta (m), cyan (c), and black (k), respectively. In the following description, the suffixes y, m, c, and k of the reference numbers are omitted except when referring to a specific image forming unit member.

[0040] In the second embodiment, the side of image forming apparatus 100 from which sheet feed cassette 306, described later, is pulled out is defined as the "front" side of image forming apparatus 100, and the side from which sheet feed cassette 306 is pushed in is defined as the "rear" side of image forming apparatus 100. Furthermore, the right side when looking at the "rear" side of image forming apparatus 100 from the "front" side is defined as the "right", and the left side when looking at the "rear" side of image forming apparatus 100 from the "front" side is defined as the "left". In FIG. 9, the "front" side of image forming apparatus 100 is the front side of FIG. 9, and the "rear" side of image forming apparatus 100 is the back side of FIG. 9.

[0041] The configuration of the image forming apparatus 100 and the image forming process will be described with reference to FIG. 9. The optical scanning device 101 is disposed vertically below the photosensitive drums 301 of the image forming units, and irradiates the photosensitive drums 301y, 301m, 301c, and 301k of the image forming units with laser beams Ly, Lm, Lc, and Lk according to image data. The photosensitive drums 301 of the image forming units are charged to a uniform potential in advance by the charging roller 302, and an electrostatic latent image is formed on the surface of the photosensitive drum 301 by discharging the electric charge only in the portion irradiated with the laser beam from the optical scanning device 101. Toner is attached to the electrostatic latent image on each photosensitive drum 301 by each developing roller 303, and a toner image is formed. A primary transfer roller 304 is disposed at a position facing each photosensitive drum 301, and a transfer voltage is applied to the primary transfer roller 304, so that the toner images on each photosensitive drum 301 are transferred sequentially onto the intermediate transfer belt 305 in a superimposed manner.

[0042] Meanwhile, a recording material 307 placed in a paper feed cassette 306 arranged vertically below the optical scanning device 101 is fed from the paper feed cassette 306 by a pickup roller 308 in synchronization with the image forming processes in the above-mentioned image forming units. The recording material 307 fed from the paper feed cassette 306 is conveyed to a secondary transfer roller 309, which transfers the four-color toner image transferred onto the intermediate transfer belt 305 onto the recording material 307. The recording material 307 onto which the toner image has been transferred is conveyed to a fixing device 310, where the toner image is fixed to the recording material 307 by applying heat and pressure. The recording material 307 that has passed through the fixing device 310 is then discharged to the outside of the image forming apparatus 100 by a discharge roller 311.

[0043] [Optical scanning device] 10 and 11 are diagrams for explaining the configuration of the optical scanning device 101. Fig. 10 is a diagram showing the configuration of the optical scanning device 101 when the optical scanning device 101 is viewed from the lid member 105 side (opening side) in a state where the lid member 105 covering the opening of the optical scanning device 101 is removed. Fig. 11 is a schematic cross-sectional view for explaining the configuration of the optical scanning device 101 and the correspondence between the laser light emitted from the optical scanning device 101 and the photosensitive drum 301.

[0044] In the optical scanning device 101 of this embodiment, the laser light L emitted from the semiconductor lasers 201, which are a plurality of light sources, is deflected by the rotating polygon mirror 104 of the deflector 107, and the laser light L is irradiated onto the corresponding photosensitive drums 301 through the optical members. The optical scanning device 101 has semiconductor lasers 201y, 201m, 201c, and 201k, collimator lenses 202y, 202m, 202c, and 202k, and cylindrical lenses 203y, 203m, 203c, and 203k. The optical scanning device 101 also has deflectors 107a and 107b having rotating polygon mirrors 104a and 104b, first imaging lenses 108a, 108b, 108c, and 108d, which are imaging members of the laser light, and second imaging lenses 109a, 109b, 109c, and 109d. Furthermore, the optical scanning device 101 has folding mirrors 110a, 110b, 110c, and 110d which are reflective members, an optical box 103 in which the above-mentioned optical members are attached, and a cover member 105 for sealing the optical box 103.

[0045] Optical box 103 is disposed vertically below the image forming unit described above, and lid member 105 is disposed vertically below optical scanning device 101. That is, lid member 105 is disposed on the side facing paper feed cassette 306 relative to optical box 103. Deflectors 107a, 107b have drive substrates 107aa, 107ba for driving and rotating rotating polygon mirrors 104a, 104b fixed to the bottom surface side of optical box 103, and rotating polygon mirrors 104a, 104b are disposed vertically below drive substrates 107a, 107b.

[0046] 10, backup portions 106, which are ribs, are provided near the longitudinal ends of the first imaging lenses 108a, 108b, 108c, and 108d. The backup portions 106 stand upright from the bottom surface of the optical box 103 toward the lid member 105, and have a length such that the clearance (distance) between the tip end toward the lid member 105 and the lid member 105 is about 1 mm. This makes it possible to prevent direct contact between the lid member 105 and optical components (such as the first imaging lens 108) inside the optical scanning device 2, which are arranged with a clearance larger than the clearance between the backup portions 106 and the lid member 105.

[0047] Next, the operation of the optical scanning device will be described. The laser light Ly emitted from the semiconductor laser 201y is made substantially parallel by the collimator lens 202y and enters the cylindrical lens 203y. The substantially parallel light beam that enters the cylindrical lens 203y is emitted as it is in the state of parallel light beam in the main scanning section, and the light beam is condensed in the sub-scanning section, enters the rotating polygon mirror 104a, and is deflected by the rotating polygon mirror 104a. Then, the deflected laser light Ly passes through the first imaging lens 108a, and then the optical path is deflected by the folding mirror 110a. The laser light Ly that has been deflected passes through the second imaging lens 109a and the opening of the optical box 103, and scans the surface of the photosensitive drum 301y at a constant speed while forming a spot on the corresponding photosensitive drum 301y.

[0048] The laser beam Lm emitted from the semiconductor laser 201m is collimated by the collimator lens 202m and enters the cylindrical lens 203m. The approximately parallel beam entering the cylindrical lens 203m is emitted as a parallel beam in the main scanning cross section, and is focused in the sub-scanning cross section, enters the rotating polygon mirror 104a, and is deflected by the rotating polygon mirror 104a. The deflected laser beam Lm passes through the first imaging lens 108b, and then has its optical path deflected by the folding mirror 110b. The laser beam Lm, whose optical path has been deflected, passes through the second imaging lens 109b and the opening of the optical box 103, and scans the surface of the photosensitive drum 301m at a constant speed while forming a spot on the corresponding photosensitive drum 301m.

[0049] The laser beam Lc emitted from the semiconductor laser 201c is collimated by the collimator lens 202c and enters the cylindrical lens 203c. The approximately parallel light beam that enters the cylindrical lens 203c is emitted as a parallel light beam in the main scanning cross section, and is focused in the sub-scanning cross section, enters the rotating polygon mirror 104b, and is deflected by the rotating polygon mirror 104b. The deflected laser beam Lc passes through the first imaging lens 108c, and then is deflected in its optical path by the folding mirror 110c. The laser beam Lc that has been deflected in its optical path passes through the second imaging lens 109c and the opening of the optical box 103, and scans the surface of the photosensitive drum 301c at a constant speed while forming a spot on the corresponding photosensitive drum 301c.

[0050] The laser beam Lk emitted from the semiconductor laser 201k is collimated by the collimator lens 202k and enters the cylindrical lens 203k. The approximately parallel light beam that enters the cylindrical lens 203k is emitted as a parallel light beam in the main scanning section, and is focused in the sub-scanning section, enters the rotating polygon mirror 104b, and is deflected by the rotating polygon mirror 104b. The deflected laser beam Lk passes through the first imaging lens 108d, and then is deflected in its optical path by the folding mirror 110d. The laser beam Lk that has been deflected in its optical path passes through the second imaging lens 109d and the opening of the optical box 103, and scans the surface of the photosensitive drum 301k at a constant speed while forming a spot on the corresponding photosensitive drum 301k. The laser beams Ly and Lm are deflected by different adjacent surfaces of the rotating polygon mirror 104a. Further, the laser beams Lc and Lk are also deflected by different adjacent surfaces of the rotating polygon mirror 104b.

[0051] [Replacing recording material] 12 is a diagram for explaining a method of replacing a recording material in the image forming apparatus 100 of the second embodiment. When a print job is executed, an image forming operation is performed in the image forming unit described above, and an image is formed on the recording material 307 fed from the paper feed cassette 306, thereby consuming the recording material 307 contained in the paper feed cassette 306. When the remaining amount of the recording material 307 in the paper feed cassette 306 is low or when all the recording materials 307 have been used up, the user or the like replenishes the recording material 307 in the paper feed cassette 306. As shown in FIG. 12, in this embodiment, the recording material 307 is replenished by pulling out the drawer-type paper feed cassette 306 to the front of the image forming apparatus 100.

[0052] FIG. 12 is a schematic cross-sectional view showing a state in the middle of the movement of the paper feed cassette 306 from a storage position where the paper feed cassette 306 is mounted in the image forming apparatus 100 to a pull-out position where the paper feed cassette 306 is pulled out from the image forming apparatus 100 to the outside. The paper feed cassette 306 is placed on a holding rail (not shown) so as to be slidable in the front-rear direction of the image forming apparatus 100. When the recording material 307 is to be added, the paper feed cassette 306 is pulled out to the outside (to the front in the figure) of the image forming apparatus 100. When the paper feed cassette 306 is pulled out to the outside from the image forming apparatus 100 by a predetermined amount, a stopper portion (not shown) restricts the paper feed cassette 306 from being pulled out further. In this way, when the paper feed cassette 306 is pulled out, the recording material 307 can be removed from the paper feed cassette 306 to add more recording material 307 or to change the type of recording material 307. When a force is applied in a direction to pull the paper feed cassette 306 further out from the position where the pull-out movement is restricted, the paper feed cassette 306 can be removed from the holding rail on which it was placed. Removing the sheet feed cassette 306 from the holding rails is performed, for example, to make it easier to refill the recording material, or to remove jammed paper when a jam occurs in which the recording material 307 gets caught in the transport path during image formation. Then, when the refilling of the recording material 307 or the removal of jammed paper from the transport path is completed, the sheet feed cassette 306 is moved on the holding rails from the position where it was pulled out or the position where it was placed on the holding rail and removed to a storage position where it is attached to the image forming apparatus 100. Then, when the sheet feed cassette 306 moves to the pushed-in position, it is fixed in a predetermined position and is ready for image formation.

[0053] As shown in FIG. 9, the optical scanning device 101 is disposed below each image forming unit in the vertical direction and above the sheet feed cassette 306 that contains the recording material 307. No partition is disposed between the optical scanning device 101 and the sheet feed cassette 306 in order to reduce the size of the image forming device 100. The sheet feed cassette 306 is made of a frame-shaped molded member, and as shown in FIG. 12, when the sheet feed cassette 306 is pulled out from the image forming device 100, the upper part of the sheet feed cassette 306 in the vertical direction is opened, and an opening 150 is formed. Therefore, a person can insert a hand H2 through the opening 150, and there is a risk that the person may accidentally touch the cover member 105 of the optical scanning device 101 and press the cover member 105.

[0054] [Installation of the cover of the optical scanning device] Fig. 13 is a schematic diagram for explaining a method for fixing cover member 105 to optical scanning device 101. As shown in Fig. 11, optical scanning device 101 is disposed so that optical box 103 is on the upper side in the vertical direction and cover member 105 is on the lower side in the vertical direction. Fig. 13 is a perspective view showing the external shape of optical scanning device 101 when optical scanning device 101 is viewed from the cover member 105 side.

[0055] The cover member 105 has snap-fit ​​structures 105a, 105b, 105c, and 105d molded integrally with the cover member 105 in order to fix it to the optical box 103. The snap-fit ​​structures 105a, 105b, 105c, and 105d are each shaped like a square with an opening in the center. Meanwhile, protrusions 103a, 103b, 103c, and 103d for fixing the cover member 105 are provided near the four corners of the optical box 103 of the optical scanning device 101.

[0056] When the lid member 105 is attached to the optical box 103, the snap-fit ​​structures 105a to 105d are elastically bent, so that the lid member 105 passes over the protrusions 103a to 103d provided on the optical box 103 corresponding to the snap-fit ​​structures 105a to 105d. Then, the protrusions 103a to 103d engage with the openings of the snap-fit ​​structures 105a to 105d. As a result, the protrusions 103a, 103b, 103c, and 103d protrude from the openings of the snap-fit ​​structures 105a, 105b, 105c, and 105d, respectively, and the lid member 105 is fixed to the optical box 103.

[0057] [Deformation of the cover of the optical scanning device] Fig. 14 is a cross-sectional view of the optical scanning device 101 for explaining the deformation of the cover member 105 when a person's hand H2 touches the cover member 105 of the optical scanning device 101. Fig. 14 is a cross-sectional view of the optical scanning device 101 viewed from the front side to the rear side, cutting the vicinity of where the snap-fit ​​structures 105a, 105d engage with the protrusions 103a, 103d in a state where the cover member 105 shown in Fig. 13 is fixed to the optical scanning device 101. In Fig. 14, the cut surface shows the rotating polygon mirrors 104a, 104b, the first imaging lenses 108a-108d, the second imaging lenses 109a-109d, and the folding mirrors 110a-110d through which the laser beams Ly, Lm, Lc, and Lk pass. Further, a backup portion 106 is provided near the first imaging lenses 108a to 108d, and the clearance (distance) between the tip end and the cover member 105 is smaller than that of the first imaging lenses 108a to 108d and the reflecting mirrors 110a to 110d.

[0058] As shown in FIG. 14, when replenishing or replacing the recording material 307, if a hand H2 is inserted through the opening 150 (FIG. 12) and touches the cover member 105, a pressing force P2 of 5 to 20 N is applied to the cover member 105 in the direction of the optical box, based on the pressing force of an average person. When the cover member 105 is bent by the pressing force P2, the snap-fit ​​structures 105a and 105d (snap-fit ​​structures 105b and 105c are not shown in FIG. 14) provided on the cover member 105 are elastically deformed in the direction of the arrow Rc in the figure. At the same time, the cover member 105 is deformed from the original position 105' (shown by a dotted line in the figure) in the direction toward the inside of the optical box 103, and comes into contact with the backup portion 106 provided on the optical box 103 for restricting the deformation. As described above, the backup portion 106 is provided near the optical components (for example, the first imaging lens 108) provided in the optical box 103. Backup part 106 has a length such that the clearance (distance) between the tip end toward cover member 105 and cover member 105 is about 1 mm. Therefore, it is possible to prevent direct contact between cover member 105 and optical components (such as first imaging lens 108) inside optical scanning device 101 that are arranged with a clearance larger than the clearance between backup part 106 and cover member 105.

[0059] As described above, even if a person's hand H2 touches the optical scanning device 101 when the paper feed cassette 306 is moved outside the image forming apparatus 100 to refill or replace the recording material, the position of the optical components does not fluctuate, causing a change in the optical characteristics or a deterioration in image quality.

[0060] In this embodiment, the configuration has been described in which the backup section 106 is provided on the optical box 103 to reduce the deflection that occurs when the human hand H2 touches the cover member 105. The backup section 106 is not limited to the optical box 103 side, and may be provided on the cover member 105 side. That is, the backup section 106 is provided on the surface of the cover member 105 facing the bottom surface of the optical box 103 on which the optical members are disposed, and is erected toward the bottom surface of the optical box 103 and has a length such that the clearance between the tip of the backup section 106 and the bottom surface of the optical box 103 is about 1 mm. As a result, even if the cover member 105 is pressed toward the optical box 103, the backup section 106 provided on the cover member 105 comes into contact with the bottom surface of the optical box 103 before the cover member 105 comes into contact with the optical members. As a result, even if the backup section 106 is provided on the cover member 105, the same effect as when the backup section 106 is provided on the optical box 103 can be achieved. In addition, regarding the position where the human hand H2 contacts the cover member 105, FIG. 14 describes the case where the hand H2 contacts the cover member 105 near the deflector 107b of the optical scanning device 101, but the same effect can be achieved even if the hand H2 contacts the cover member 105 near the other deflector 107a.

[0061] As described above, according to this embodiment, it is possible to prevent deterioration of image quality caused by pressing the optical box. EXAMPLES

[0062] In the first and second embodiments, a backup portion that is a rib portion that protects the cover member of the optical scanning device from contacting the optical components and the like arranged in the optical scanning device when the cover member is pressed and bent is described. In the third embodiment, the processing and material of the cover member that protects the electronic devices inside the optical scanning device having such a backup portion from static electricity is described.

[0063] [Cover part for optical scanning device] Fig. 15 is a perspective view of optical scanning device 401 having an external shape similar to that of optical scanning device 101 described in Example 2. Optical scanning device 401 has an optical box 403 and a lid member 405, and Fig. 15 is a perspective view of optical scanning device 401 with the opening of optical box 403 sealed with lid member 405, as viewed from the direction of lid member 405.

[0064] The cover member 405 of this embodiment is molded from resin, and the flat area 402, which is the outer surface that can be touched by a human hand H2 described in the second embodiment (the surface of the cover member 405 opposite to the surface facing the optical box 403), is roughened by embossing. The embossing is performed using a processing method such as etching, sandblasting, or hairline finishing, and the roughened flat area 402 is shown by hatching in FIG. 15. Generally, when two substances come into contact and then separate, the atoms of each substance move and remain in one of the substances, so that electrons are biased toward one substance and electrons are reduced in the other substance. In particular, the greater the frictional force when the two substances come into contact, the greater the amount of static electricity that the substances are charged with. As described above, when a person's hand touches cover member 405 of optical scanning device 401 and optical scanning device 401 becomes charged with static electricity, the greater the roughness of the roughened surface provided on flat area 402 of cover member 405, the smaller the frictional force between cover member 405 and the person's hand. As a result, the amount of charge on cover member 405 also becomes smaller.

[0065] The cover member 405 is made of resin, and the resin material has a surface electrical resistivity of 1×10 11 A material with static electricity dissipation properties of Ω / m or less is used. The resin material used for the cover member 405 of this embodiment is difficult to be charged because of its high surface electrical resistivity, and even if a charged object (human hand) comes into contact with it, the charge can be dissipated relatively quickly. As a result, the cover member 405 does not cause a strong electrostatic discharge (ESD), so that the ICs such as the laser driver, motor driver, and BD sensor inside the optical scanning device 401 can be protected from electrostatic discharge. This makes it possible to prevent degradation of image quality due to IC damage, etc.

[0066] In this embodiment, the entire outer surface of the cover member 405 is configured as a flat surface, and the entire flat surface is roughened by embossing. For example, if the cover member 405 has unevenness and cannot be configured as a single flat surface, a part of the cover member 405 near the driver IC that controls the deflector can be roughened to protect electrical components that are vulnerable to electrostatic discharge from static electricity, and the same effect can be achieved. In this embodiment, the optical scanning device 401 having the same external shape as the optical scanning device 101 of the second embodiment is used for the description, but the optical scanning device 2 of the first embodiment can also achieve the same effect by performing the same embossing on the cover member 5.

[0067] As described above, according to this embodiment, even if a hand inserted into the image forming apparatus touches the cover member when replacing a cartridge or replenishing a recording material, the amount of charge on the cover member can be reduced. Therefore, an optical scanning device having resistance to various ESD modes can be provided in an optical scanning device having electronic components that are vulnerable to electrostatic discharge. In addition, in the above-mentioned first and second embodiments, the present invention has been described using an optical scanning device used in an image forming apparatus called an in-line type in which multiple process cartridges are arranged. The present invention can also be similarly applied to an optical scanning device of a monochrome image forming apparatus having one process cartridge.

[0068] As described above, according to this embodiment, it is possible to prevent deterioration of image quality caused by pressing the optical box. [Explanation of symbols]

[0069] 1. Image forming device 2 Optical Scanning Device 3 Optical box 5 Cover member 40 Cartridge Tray

Claims

1. an optical scanning device having a light source, a deflector having a rotating polygonal mirror for deflecting and scanning a laser beam emitted from the light source, an imaging lens for imaging the deflected and scanned laser beam, an optical box for holding the light source, the deflector, and the imaging lens, and a lid member for covering an opening of the optical box; an image carrier having an electrostatic latent image formed on a surface thereof by being scanned with the laser beam emitted from the optical scanning device; and a developing means for supplying toner to the image carrier to develop the electrostatic latent image, the image forming apparatus has a movable unit movable to the outside of the image forming apparatus, the movable unit and the optical scanning device are arranged opposite to each other when the movable unit is housed inside the image forming apparatus, no partition is provided between the optical scanning device and the movable unit, and the optical scanning device is arranged so that the cover member is exposed to a space generated when the movable unit is moved to the outside of the image forming apparatus, The optical box is provided with a backup section whose clearance with the lid member is smaller than the clearance with the optical components including the imaging lens, and even if a user inserts their hand into the space and pushes the lid member with their hand, causing the lid member to bend, the lid member is supported by contact with the backup section, thereby preventing the lid member from coming into contact with the optical components.

2. 2. The image forming apparatus according to claim 1, wherein the moving unit is a process cartridge having the image bearing member, or a cartridge tray for accommodating the process cartridge.

3. 3. The image forming apparatus according to claim 1, wherein the optical scanning device is disposed vertically above and the image carrier is disposed vertically below, and the cover member has an opening for passing the laser light therethrough.

4. 2. The image forming apparatus according to claim 1, wherein the moving unit is a paper cassette for accommodating a recording medium onto which a toner image is transferred.

5. 5. The image forming apparatus according to claim 1, wherein the optical scanning device is disposed vertically below and the image carrier is disposed vertically above, and the optical box has an opening for passing the laser light.

6. 6. The image forming apparatus according to claim 1, wherein the rotary polygon mirror is disposed vertically below a drive board for driving the deflector.

7. 7. The image forming apparatus according to claim 6, wherein the cover member has a plurality of fixing portions for fixing to the optical box, at least some of the plurality of fixing portions being elastically fixed.

8. 8. The image forming apparatus according to claim 6, wherein the cover member is made of resin, and at least a part of the area on the side facing the moving unit is roughened.

9. The cover member is made of resin and has a surface electrical resistivity of 1×10 １１ 9. The image forming apparatus according to claim 6, wherein the resistance is Ω·m or less.

Images