JP4193907B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus typified by an electrophotographic printer, copying machine, facsimile machine, multifunction machine, and the like. In particular, an electrostatic latent image is formed by exposing a photoconductor to light according to image information. The present invention relates to an image forming apparatus of a type in which a light exit surface portion of an exposure apparatus to be formed is disposed at a position below a developing apparatus.

  In this type of image forming apparatus, as illustrated in FIG. 12, basically, the surface of the drum-shaped photoconductor 110 rotating in the direction of the arrow is uniformly charged by the charging device 120 and then charged. The surface of the photosensitive member is exposed to light H corresponding to image information from the exposure device 130 to form an electrostatic latent image, and then the electrostatic latent image is passed from the housing 141 to the developing roll when passing through the developing device 140. The developed image is developed by developing with the developer supplied via the developer carrier 142, and the developed development image is transferred directly to a recording medium such as recording paper or via an intermediate transfer member. In particular, an image is formed by fixing, and in particular, a light exit surface portion (a transparent glass window, a reflection mirror, or a lens) 135 from which the light H of the exposure device 130 exits toward the photosensitive member 110 is provided. developing It may be disposed below the position of the location 140.

  In this case, the light emission surface 135 is roughly arranged at a position below the developing device 140 together with the main body 131 including the light source of the exposure device 130 (FIG. 5A), and the light emission. The surface portion 135 is disposed at a lower position of the developing device 140, but the main body portion 131 may be disposed at the same height position as the developing device 140 or a higher position (FIG. 5B). In particular, in the latter case, the light exit surface 135 has a configuration in which an optical device such as a reflection mirror that forms an optical path for guiding the light emitted from the main body 131 to the photosensitive member 110 is arranged.

  However, the image forming apparatus of the type in which the light exit surface portion 135 of the exposure device 130 is disposed below the developing device 140 has the following problems.

  That is, because the light exit surface 135 of the exposure device 130 is located below the developing device 140, a small amount of developer may fall from the developing device 140 onto the light exit surface 135, and the light exit surface may become dirty. In this case, the light H emitted from the light exit surface 135 due to the contamination and exposed to the photoconductor 110 is not normally emitted, and an electrostatic latent image cannot be favorably formed on the photoconductor 110. There is a problem that image quality defects occur.

  Conventionally, in general, in order to prevent the developer supplied from the developing device to the photosensitive member from rising and leaking into the apparatus from the developing device and being contaminated, the developing device is brought into contact with the surface of the photosensitive member. It is known to provide a film seal that seals the gap between the photosensitive member (Japanese Patent Laid-Open No. 10-10864, etc.). However, in this case, the developer accumulates between the film seal or the seal and the attachment site (such as the housing of the developing device), and the accumulated developer is caused by vibration during operation or external impact. It may fall and adhere to the surface (developer layer) of the developing roll in a solidified state. When the development is performed with the solid developer adhered, there is a possibility that a development failure and an image quality defect may occur. Therefore, the proposed means cannot be an effective means for solving the above problem.

  The present invention has been made in view of such circumstances, and its main object is to form an image of the type in which the light exit surface portion of the exposure apparatus as described above is disposed at a lower position of the developing device. An object of the present invention is to provide an image forming apparatus capable of reliably preventing a light exit surface portion of an exposure apparatus from being contaminated by a developer that falls from the developing device and obtaining a good image quality without image quality defects.

The image forming apparatus of the present invention (first invention) capable of solving the above-described problems includes a photosensitive member rotating in a predetermined direction, a charging device for charging the surface of the photosensitive member, and the photosensitive member charged by the charging device. An exposure apparatus that forms an electrostatic latent image by exposing light according to image information to the surface of the body, and development that develops the electrostatic latent image formed by the exposure apparatus with a developer supplied from within the housing A plurality of image forming units having at least a developing device having a roll and arranged in a row, and arranged in contact with the photoconductor above the plurality of image forming units. An intermediate transfer member to which an image formed by development of the developing device is transferred to the photosensitive member of an image unit; and a light exit surface portion of the light in the exposure device disposed at a position below the developing device ; It said each of the imaging unit From a state in which the definitive photoreceptor and the developing device are disposed an image formed on the row USo fixing position, wherein the photosensitive member to a predetermined retracted position apart from the developing device, intersects the direction obtained by arranging said plurality of image forming units a lifting and lowering mechanism for raising along the lifting movement direction, with mounted on the charging device side a and the portion close to the photosensitive body housing of the developing device, the photosensitive member is positioned in front KiSo fixing position A film-like member that is in contact with the surface of the photoconductor in a state and is spaced from the surface of the photoconductor in a state in which the photoconductor is located at the retracted position. It is attached so that it may incline to the said developing roll side with respect to the said raising / lowering direction when it is spaced apart from the surface.
In addition, the present invention includes at least the charging device, the exposure device, and the developing device, a plurality of image forming units arranged in a row, and the photoconductor above the plurality of image forming units. An intermediate transfer member to which an image formed by development of the developing device is transferred to the photosensitive member of each image forming unit, and the exposure disposed at a position below the developing device. and Idemitsu surface of the in the device light, the said photosensitive between a predetermined retracted position photoconductor and said developing device to an image forming row USo fixing position photoconductor is spaced apart from the developing device in image forming units An elevating mechanism that elevates the body along an elevating direction that intersects the direction in which the plurality of image forming units are arranged , and a portion of the housing of the developing device that is on the charging device side and close to the photoconductor. And Furthermore, a film-like member that is in contact with the surface of the photoconductor when the photoconductor is in the regular mounting position and that is separated from the surface of the photoconductor when the photoconductor is in the retracted position. The film-like member is attached so as to be inclined to the developing roll side with respect to the ascending / descending direction when contacting the surface of the photoreceptor. It is.

  The image forming apparatus according to the second aspect of the present invention is the image forming apparatus premised on the first aspect of the invention, in the exposure direction of the light emitted from the light exit surface portion between the charging device and the developing device. A passage forming member that forms a passage through which air flows is disposed up to a position approaching the photoconductor, and a portion of the housing of the developing device that is close to the photoconductor and adjacent to the charging device or the passage formation A film-like member is attached to a portion of the member that is close to the photosensitive member and adjacent to the developing device in a state where the upper end of the member is in contact with the surface of the photosensitive member.

  In the image forming apparatus according to the first and second aspects of the present invention, the film-like member is a cross section that gradually widens toward the upper end side of the film-like member between the housing part or the passage-forming member part as an attachment site. At the time when the photosensitive member and the developing device are set in the proper mounting position in a state where a gap space having a shape is formed, the upper end side of the film-like member is pressed against the surface of the photosensitive member. Then, it bends toward the housing part or the passage forming member part serving as the attachment part and touches at least the front edge of the housing part or the passage forming part so as to close the gap space so as to contact the surface of the photoreceptor. It is good to comprise so that it may touch.

  As described above, according to the present invention, in the image forming apparatus of the type in which the light exit surface portion of the exposure apparatus is disposed at the lower position of the developing device, the light exit surface portion of the exposure apparatus is caused by the developer falling from the developing device. Can be reliably prevented. As a result, it is possible to perform good image formation free from image defects due to contamination of the light exit surface portion.

[Embodiment 1]
1 and 2 show Embodiment 1 of the present invention. FIG. 1 is a schematic view showing an image forming apparatus to which the present invention is applied, and FIG.

  The image forming apparatus intermediates four color toner images of yellow (Y), magenta (M), cyan (C), and black (K) formed individually by four image forming units 10Y, 10M, 10C, and 10K. It is possible to form a so-called full-color image by performing primary transfer so as to be superimposed on the surface of the intermediate transfer belt 20 of the transfer mechanism and then performing secondary transfer from the intermediate transfer belt 20 to the recording paper P side as a recording material. This is a possible color image forming apparatus. Further, this apparatus can also form a monochrome image or the like by operating only some of the four image forming units, for example, the black image forming unit 10K. .

  First, each of the image forming units 10 forms the toner images of the four colors described above by an electrophotographic process. The image forming unit 10 is formed on the lower side of the intermediate transfer belt 20 at the substantially central portion of the image forming apparatus main body 1. Are arranged in a horizontal state with a space therebetween. Each of the image forming units 10 basically has a photosensitive drum 11 in which an organic photosensitive layer or the like is disposed on an outer peripheral surface of a drum that is rotationally driven in a direction indicated by an arrow at a predetermined speed. A charging roll 12 that uniformly charges the surface, an exposure device 13 as a latent image forming device that forms an electrostatic latent image by exposing the surface of the charged photosensitive drum 11 to light according to image information, and A developing device 14 that develops the electrostatic latent image with a developer of a predetermined color, a primary transfer roll 15 that electrostatically transfers a toner image formed by the development to the intermediate transfer belt 20, and the surface of the photosensitive drum 11. And a drum-type drum cleaning device 16 for cleaning the drum.

  Among these, the exposure device 13 is housed in a housing sealed box 17 disposed on the lower side of the four image forming units 10, and is converted into image signals separated for each color from four semiconductor lasers (not shown). Laser beams LB-Y, LB-M, LB-C, and LB-K emitted in response to the rotary polygon mirror 18 through a predetermined optical system (lens or the like) are deflected and scanned, and then a plurality of unillustrated ones. Scanning exposure is performed obliquely from below on the respective photosensitive drums 11 facing each other through a single reflection mirror. Reference numeral 17a in the figure denotes a light output surface portion provided with a transparent glass surface for transmitting and emitting each laser beam LB from the inside of the housing sealed box 17 toward the photosensitive drum 11 of each image forming unit 10.

  Further, each developing device 14 uses a two-component developer composed of toner and carrier as the developer G, and as shown in FIG. The developer G is accommodated in the developer and is agitated and conveyed by two developer agitating / conveying members (for example, augers) 42 and 43 that rotate in a parallel state. Finally, an opening of the housing 40 facing the photosensitive drum 11 44 is supplied to a developing roll 45 that is rotationally driven to 44. Further, each of the developing devices 14 is illustrated from toner cartridges 19Y, 19M, 19C, and 19K in which the corresponding colors (Y, M, C, and K) of toner T (or developer G) are accommodated. The developer storage / circulation conveyance path 41 is appropriately replenished via a developer replenishing device. Further, a primary transfer bias having a polarity opposite to the charging polarity of the toner image on the photosensitive drum 11 is applied to the primary transfer roll 15 from a bias power supply device (not shown).

  In each of the image forming units 10, after the surface of the photosensitive drum 11 rotating in the direction of the arrow is uniformly charged by the charging roll 12, the image signal is color-separated from the exposure device 13 on the charged surface. The electrostatic latent image is written by scanning and exposing the laser beam LB corresponding to the light through the light exit surface portion 17a, and then the latent image is developed with the toner T of the developer G supplied from the developing device 14. The toner image is finally transferred onto the surface of the intermediate transfer belt 20 passing between the photosensitive drum 11 and the primary transfer roll 15 in sequence. The surface of the photosensitive drum 11 after the transfer is cleaned by removing residual toner and the like by the blade of the drum cleaning device 16.

  Next, the intermediate transfer belt 20 has an endless shape having a two-layer structure in which a surface layer such as silicone rubber is laminated on a belt base material such as a polyimide film containing a conductive material and the like and adjusted in volume resistivity. A belt, which is stretched around a drive roll 21, a backup roll 22 of a secondary transfer unit, and a plurality of driven rolls 23, 24... And between the driven rolls 23, 24, the photosensitive drum of each image forming unit 10. 11 is in contact with each other, and is rotated in the direction of arrow B by the rotational power of the drive roll 21.

  Further, a secondary transfer roll 25 is disposed around the intermediate transfer belt 20 to press the intermediate transfer belt 20 against the backup roll 22 to form a pressure contact area of the secondary transfer portion. A power supply member 27 for supplying a secondary transfer bias having the same polarity as the charging polarity of the toner image on the intermediate transfer belt 20 from a bias power supply device (not shown) to the conductive shaft of the backup roll 22 is provided. It arrange | positions so that it may contact. Further, a blade type belt cleaning device 26 for cleaning the surface of the belt 20 is disposed at a position facing the drive roll 21 of the intermediate transfer belt 20.

  The toner image (multiple) transferred to the intermediate transfer belt 20 is conveyed to a secondary transfer portion facing the secondary transfer roll 25 arranged to face the backup roll 22 as the belt 20 rotates. Is done. The toner image on the intermediate transfer belt 20 is sent out by a paper feeding mechanism 31 from a paper storage tray 30 disposed below the exposure device 13 in accordance with the image formation and secondary transfer timing of the toner image. Then, electrostatic transfer is electrostatically transferred onto the recording paper P having a predetermined size that is conveyed to the secondary transfer portion through the paper conveyance path on which the resist roll 32 and the like are arranged. The surface of the intermediate transfer belt 20 after the secondary transfer is cleaned by removing residual toner and the like by the blade of the belt cleaning device 26. A one-dot chain line in FIG.

  In addition, the recording paper P on which the toner image is transferred from the intermediate transfer belt 20 is naturally peeled off from the intermediate transfer belt 20 portion when passing through the secondary transfer portion, and then pressed with the heating roll 36 in the fixing device 35. A member (pressure pad, pressure roll, etc.) 37 is sent so as to pass through the pressure contact area of the member 37 and subjected to heat fixing processing, and then discharged to the outside of the apparatus main body 1 (paper discharge accommodating portion 1a) by the discharge roll 38. Is done. A desired color image or the like is formed on the recording paper P through the above process.

  In this image forming apparatus, as shown in FIGS. 2 and 3, the film-like member 50 is in contact with the surface of the photosensitive drum 11 on the housing 40 of the developing device 14 in each image forming unit 10. It is attached with.

  The film-like member 50 is attached to a portion 40 </ b> A that is close to the photosensitive drum 11 of the housing 40 and adjacent to the charging device 12. In this example, the opening 44 of the housing 40 is attached to the end near the charging device 12. The film-like member 50 is not particularly limited as long as it is a film-like material that does not wear and damage the surface of the photosensitive drum 11 due to contact and is easy to be in uniform contact with the surface. Materials such as film are used. Further, the thickness, dimensions, etc. of the film-like member 50 are also selected as appropriate.

  In addition, as shown in FIG. 3a, the film-like member 50 has a cross-sectional shape (for example, a wedge shape or the like) that gradually spreads toward the upper end side of the film-like member 50 between the housing portion 40A that is an attachment site in advance. Are attached in such a manner that a gap space E having a V-shaped cross section is formed. In this example, a notch taper surface 46 is formed in advance on the distal end side of the end of the housing portion 40A, which is the attachment site, and is inclined so as to move away from the surface side of the photosensitive drum 11 and approach the developing roll 45 side. The upper end 50a side of the film-like member 50 is opposed to the tapered surface 46 to be a free end, and the remaining lower end 50b is attached to the original outer peripheral surface of the housing portion 40A with an adhesive or the like. It is fixed by fixing means as appropriate. In addition, as shown in FIG. 3b, the film-like member 50 is indicated by a dotted arrow F at the upper end portion 50a side of the film-like member when the photosensitive drum 11 and the developing device 14 are set to the proper mounting position. As described above, the photosensitive drum 11 is pushed by the surface of the photosensitive drum 11 so as to bend toward the housing portion 40A and touches at least the front end edge of the housing portion 40A to close the gap space E. It is attached so as to contact the surface. In this example, the upper end side 50a of the film-like member 50 is deformed so as to be in full contact with the notch taper surface 46, and thus the gap space E disappears (is eliminated). The case where it contacts with the surface of is shown.

  Therefore, in this image forming apparatus, by attaching the film member 50 as described above, the gap between the end 40A of the housing 40 of the developing device 14 near the charging device 12 and the surface of the photosensitive drum 11 is closed. Therefore, only the toner of the developer G or the toner and the carrier are prevented from dropping from the developing device 14 to the light exiting surface portion 17a of the exposure device 13 at the lower position, and the light exiting surface portion 17a is soiled by the developer G. Almost no. As a result, at the time of image formation, the laser beam LB from the exposure device 13 is normally emitted from the light exit surface portion 17a and irradiated onto the surface of the photosensitive drum 11, so that a good latent image is formed, and consequently the light exit surface portion. It is possible to perform good image formation free from image quality defects due to 17a.

  Further, the film-like member 50 is mounted in advance in such a state that the gap space E as described above is formed between the film portion 50 and the housing portion 40A, and the photosensitive drum 11 and the developing device 14 are set at a proper mounting position. Since the upper end portion 50A side is bent to the surface of the photosensitive drum 11 and closes the gap space E, the film-like member 50 is contacted with the surface of the photosensitive drum 11. There is no space for the developer G to accumulate between the mounting portion and the housing portion 40A.

[Embodiment 2]
FIG. 4 is an enlarged view showing a main part in the second embodiment of the present invention. The image forming apparatus according to the second embodiment is the same as the first embodiment except that a passage forming member 60 is disposed and the film member 50 is attached to a part of the passage forming member 60 as shown in FIG. The image forming apparatus has the same configuration.

  The passage forming member 60 forms a passage through which air flows between the charging device 12 and the developing device 14 along the exposure direction of the laser beam BK emitted from the light exit surface portion 17a. In this example, as shown in FIGS. 4 and 5, three first to third partition panels 61 to 63 are used as the passage forming member 60.

  Among these, the first partition panel 61 is arranged in a state of partitioning between the light exit surface portion 17a and the charging device 12 (housing 12a) and closing the gap therebetween, and the second partition panel 62. Is arranged with a predetermined gap near the developing device 14 of the first partition panel 61, and in a state of partitioning between the light exit surface portion 17a and the vicinity of the photosensitive drum 11 and closing the gap therebetween. It is installed. A first air passage 65 having a state along the exposure direction of the laser beam LB emitted from the light exit surface portion 17a is formed between the first partition panel 61 and the second partition panel 62. Further, the third partition panel 63 is arranged in a state of being spaced apart from the developing device 14 of the second partition panel 62 by a predetermined distance, and is also arranged in a state of being spaced from the housing 40 of the developing device 14. It is installed. The third partition panel 63 forms a second air passage 66 that communicates with and is adjacent to the first air passage 65 with the second partition panel 62. Moreover, the third partition panel 63 forms a third air passage 67 adjacent to the second air passage 66 between the third partition panel 63 and the outer peripheral surface of the housing 40 of the developing device 14. Each of the partition panels 61 to 63 is formed of a metal plate or a plastic molding plate such as ABS. Reference numeral 69 in the drawing is a seal member for closing the gap between the upper end portion of the first partition panel 61 and the housing 12a of the charging device 12.

  Further, a film-like member 50 similar to that of the first embodiment is attached to the upper end portion 63A of the third partition panel 63 in the passage forming member 60. Also in this example, a notched tapered surface 63b is formed at the upper end portion of the panel 63 so that the gap space E is formed between the film-like member 50 and the upper end portion of the third partition panel 63 in advance. (Fig. 5a).

  In the image forming apparatus according to the second embodiment, when the photosensitive drum 11 and the developing device 14 are set at the regular mounting positions, as shown in FIGS. 4 and 5b, the third of the passage forming member 60 is provided. The film-like member 50 attached to the upper end portion 63A of the partition panel 63 is deformed in the same manner as in the first embodiment, and the upper end portion 60a is in contact with the surface of the photosensitive drum 11. As a result, the gap between the upper end portion 63A of the third partition panel 63 and the surface of the photosensitive drum 11 is closed by the film-like member 50, so that the developer G from the developing device 14 falls to the first air passage 65 side. Intrusion is prevented.

  In this image forming apparatus, the first air passage 65, the second air passage 66, and the third air passage 67 are formed by the passage forming member 60, so that, for example, in the main body 1 of the image forming apparatus. In the case where an exhaust fan is provided, the air moves so as to rise in the first air passage 65 (dashed line arrow N1), and the suction force by the exhaust fan acts in the second air passage 66. After the air N1 that has risen in the first air passage 65 flows in, the air N1 moves toward the lower side of the passage 66 (a dashed line arrow N2), and in the third air passage 67, the suction force by the exhaust fan is increased. The air moves so that the air flows toward the lower side of the passage 67 (one-dot chain arrow N3). Thereby, after the air in the first air passage 65 rises, an air flow that flows so as to flow into the second air passage 66 and to be discharged is generated (dashed line arrows N1 and N2). The developer G or the like does not fall into the passage 65 and enter. Further, the airflow at that time is surely generated because the gap between the upper end portion 63A of the third partition panel 63 and the surface of the photosensitive drum 11 is closed by the film-like member 50. Furthermore, when a cloud or the like in which toner particles float is generated near the opening 44 of the developing device 14, the toner or the like is discharged through the third air passage 67.

  Therefore, in this image forming apparatus, since the developer G falling from the developing device 14 is blocked by the film-like member 50, it is also blocked by the above-described airflow through each passage formed by the passage forming member 60. The light exit surface portion 17a is further prevented from being soiled by the developer G. As a result, at the time of image formation, the laser beam LB from the exposure device 13 is normally emitted from the light exit surface portion 17a and irradiated onto the surface of the photosensitive drum 11, so that a good latent image is formed, and consequently the light exit surface portion. It is possible to perform good image formation free from image quality defects due to 17a. In addition, since the film-like member 50 is attached in the same manner as in the first embodiment, the above-described effects can be obtained in substantially the same manner as in the first embodiment.

  In the second embodiment, if necessary, a blower fan or the like is connected to the first air passage 65 so that air is gently blown, or the second or third air passages 66, 67 are configured. An air intake fan or the like may be connected to the air intake so as to actively suck air. As a result, the airflow as described above can be generated more reliably, and as a result, the intrusion of the developer into the first air passage 65 can be more reliably prevented.

  Moreover, in Embodiment 2, it is good also as a structure illustrated in FIG.6 and FIG.7 as a channel | path formed with the channel | path formation member 60 as needed. The configuration example shown in FIGS. 6 and 7 does not use the third partition panel 63 in the second embodiment, but uses the first partition panel 61 and the second partition panel 62, and the first air passage 65 and Since the second air passage 66 is formed, the third air passage 67 as described above is not formed. In this configuration example, a part of the outer peripheral surface of the housing 40 of the developing device 14 is also used as a passage forming member formed by the second air passage 66. And when comprised in this way, it is the same as that of the case in above-mentioned Embodiment 2 except the movement (N3) of ventilation | gas_flowing by the passage not producing | generating by the 3rd air passage 67 being formed. The effect is obtained.

[Embodiment 3]
8 and 9 show the third embodiment of the present invention. FIG. 8 is a schematic view showing the main part of the image forming apparatus, and FIG. 9 is an explanatory view showing the attachment state of the film-like member. .

  As shown in FIG. 8, the image forming apparatus according to this embodiment integrates related parts (a driving roll 21, a primary transfer roll 15, a cleaning device 26 and the like) around the intermediate transfer belt 20. In addition to the transfer unit 200, the photosensitive drum 11, the charging device 12, and the cleaning device 16 among the image forming units 10 are integrated into a “process cartridge 100”, and then the intermediate transfer unit 200 and the process cartridge 100 are combined. The image forming apparatus has the same configuration as that of the image forming apparatus according to the first embodiment except that the image forming apparatus is configured to be moved up and down by a predetermined lifting mechanism. In other words, in this image forming apparatus, the intermediate transfer unit 200 and the process cartridge 100 are both moved upward (in the direction of the arrow X) from the normal mounting position by operating the lifting mechanism in maintenance work, component replacement, or the like. As a result, it rises to a predetermined retreat position. At this time, the developing device 14 does not rise and is in a fixed position. Further, the intermediate transfer unit 200 and the process cartridge 100 are stopped in a state where they are separated by a predetermined distance K when they are raised to their retracted positions.

  As a result, the process cartridge 100 (particularly the photosensitive drum 11) is separated from the developing device 14. In addition, the surface of the photosensitive drum 11 is kept away from the intermediate transfer belt 20. In this state, maintenance work and replacement work for the process cartridge 100 and the intermediate transfer unit 200 are performed. When the operation is completed, the above-described lifting mechanism is operated again, so that the intermediate transfer unit 200 and the process cartridge 100 are lowered (in the arrow Y direction) and stopped at the regular mounting position. ing.

  In the image forming apparatus having such an intermediate transfer unit 200 and a process cartridge 100 ascending / descending mechanism, as shown in FIG. 9, the film-like member 50 is moved in particular in the ascending / descending direction of the process cartridge 100 (arrow X, Y direction, This also corresponds to the vertical direction) and is attached in advance to the attachment site (developing device housing portion 40A and passage forming member portion) so as to be inclined to the developing device 14 side. That is, the film is attached so that the angle θ formed by the film-like member 50 with respect to the up-and-down movement direction becomes larger than 0 °. Preferably, the angle θ is set to be about 10 to 30 °.

  In this image forming apparatus, by attaching the film-like member 50 as described above, as shown in FIG. 10, the upper end portion 50a of the film-like member is a photosensitive drum particularly when the process cartridge 100 is raised and lowered. 11 is separated from or comes into contact with the surface of the film 11, but since the angle θ is set to an angle larger than 0 °, the upper end portion 50a of the film-like member is in contact with the photosensitive drum at the time of the lowering contact. 11 is in gentle contact with the surface (cylindrical surface) 11 and bent flexibly. As a result, the upper end portion 50a of the film-like member is prevented from being deformed or the surface of the photosensitive drum 11 is prevented from being damaged.

Further, since the film-like member 50 is attached to the developing device 14 side with respect to the up-and-down movement direction of the process cartridge 100 corresponding to the vertical direction, the film-like member 50 is separated when it is raised. In this case, even if it is restored to a state where it is separated from the housing portion 40A or the like of the attachment site, the inclined state is still maintained. As a result, even if the developer adheres to the inner side surface (the surface on the developing device side) of the upper end portion 50a of the film-like member at that time, it falls to the inside of the housing 40, and the light exit surface portion 17a of the exposure device 13 on the side of there is an advantage cormorants have and less likely to fall. Therefore, it is possible to prevent the light exit surface portion 17a from being contaminated by the falling developer.

[Other embodiments]
In the first to third embodiments, as a means for attaching the film-like member 50 to the housing part 40A or the like, which is an attachment part, so as to form a gap space E, a notched tapered surface 46 or the like is formed on the attachment part side. However, as shown in FIG. 11a, the mounting surface of the housing portion 40A, which is the mounting portion, is flat and the film-like member 50 is fixed to the lower end 50b side. Then, it may be configured to be attached in advance so that the upper end portion 50a side is kept away from the attachment surface. Even in such a configuration, when the photosensitive drum 11 and the developing device 14 are set at the proper mounting position, the film-like member 50 is deformed so as to bend toward the mounting surface as shown in FIG. With the space E closed, it comes into contact with the surface of the photosensitive drum 11. Also in this case, when the process cartridge 100 is configured to move up and down as described above, the film-like member 50 is on the developing device 14 side with respect to the moving up and down direction (arrow X, Y direction). It is desirable to attach it in a state inclined at about the angle θ described above.

  In the first to third embodiments, when the film-like member 50 is attached to the housing portion 40A or the passage forming member portion 60 (63) of the developing device 14, a sponge or the like is present so as to be present in the gap space E described above. You may comprise so that a soft elastic material may be attached. In such a configuration, when the film member 50 is deformed so as to fall into the housing portion 40A or the passage forming member portion 60 (63), a waste of developer or the like is accumulated between the attachment portions. It is possible to accurately avoid the formation of a gap.

  In the first to third embodiments, the case where the main body of the exposure device 13 is disposed at a position below the developing device 14 has been exemplified. However, in the present invention, the main body has a height equal to or higher than the developing device 14. The present invention can be similarly applied to an image forming apparatus having a configuration in which only the light exit surface portion (17a) is disposed at a position below the developing device.

  Further, in Embodiments 1 to 3, the drum-shaped photoconductor (11) is exemplified, but in the present invention, a belt-shaped photoconductor may be used. Further, although the case where the intermediate transfer belt 20 is used has been described, the present invention may of course be an image forming apparatus that does not use the intermediate transfer method.

1 is a schematic diagram illustrating a color image forming apparatus according to Embodiment 1. FIG. The principal part sectional drawing which shows the structure which attached the film-like member in each image forming unit. Explanatory drawing which shows the attachment state of the film-like member of FIG. FIG. 6 is a cross-sectional view of a main part showing a configuration in which a film-like member and a passage forming member are attached in each image forming unit of the image forming apparatus according to Embodiment 2. Explanatory drawing which shows the attachment state of the film-like member of FIG. FIG. 10 is a main part sectional view showing a modification of the image forming apparatus according to the second embodiment. Explanatory drawing which shows the attachment state of the film-like member of FIG. FIG. 9 is a schematic diagram illustrating a main part of an image forming apparatus according to a third embodiment. FIG. 9 is a main part explanatory view showing a configuration of a film-like member attached in each image forming unit of the image forming apparatus of FIG. 8. FIG. 9 is a schematic explanatory diagram illustrating a state during a lifting operation in the image forming apparatus of FIG. 8. Explanatory drawing which shows the other structural example regarding attachment of a film-like member. The conceptual diagram which shows the structural example regarding arrangement | positioning of the light emission surface part of exposure apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Photosensitive drum (photoconductor), 12 ... Charging device, 13 ... Exposure device, 14 ... Developing device, 17a ... Light emission surface part, 40 ... Housing, 40A ... Housing part, 50 ... Film-like member, 50a ... Upper end part, 60 ... passage forming member, 61 to 63 ... partition panel (passage forming member), 63A ... passage forming member portion, E ... gap space.

Claims (2)

A photosensitive member rotating in a certain direction, a charging device for charging the surface of the photosensitive member, and the surface of the photosensitive member charged by the charging device is exposed to light according to image information to form an electrostatic latent image. An exposure apparatus to be formed, and a developing apparatus having at least a developing roll for developing the electrostatic latent image formed by the exposure apparatus with a developer supplied from within the housing, and arranged in a row. A plurality of image forming units ,
An intermediate transfer member that is disposed in contact with the photoconductor on the upper side of the plurality of image forming units, and onto which an image formed by development of the developing device is transferred to the photoconductor of each image forming unit;
A light exit surface portion of the light in the exposure apparatus disposed at a position below the developing device ;
Wherein the state of the photosensitive member and the developing device are disposed an image formed on the row USo fixing position in each image forming unit, wherein the photosensitive member to a predetermined retracted position apart from the developing device, the plurality of image forming units An elevating mechanism that elevates along the elevating direction intersecting the aligned direction ;
Wherein together is attached to the charging device side a and the portion close to the photosensitive body housing of the developing device, said state in which the photosensitive member is positioned in front KiSo fixing position in contact with the surface of the photosensitive member, and the A film-like member spaced from the surface of the photoconductor in a state where the photoconductor is located at the retracted position;
The image forming apparatus, wherein the film-like member is attached so as to be inclined to the developing roll side with respect to the ascending / descending direction when being separated from the surface of the photoreceptor. . A photosensitive member rotating in a certain direction, a charging device for charging the surface of the photosensitive member, and the surface of the photosensitive member charged by the charging device is exposed to light according to image information to form an electrostatic latent image. An exposure apparatus to be formed, and a developing apparatus having at least a developing roll for developing the electrostatic latent image formed by the exposure apparatus with a developer supplied from within the housing, and arranged in a row. A plurality of image forming units ,
An intermediate transfer member that is disposed in contact with the photoconductor on the upper side of the plurality of image forming units, and onto which an image formed by development of the developing device is transferred to the photoconductor of each image forming unit;
A light exit surface portion of the light in the exposure apparatus disposed at a position below the developing device ;
It said plurality of image forming units the photosensitive member between a predetermined holding position where the photoconductor photosensitive member and the developing device is an image forming row USo fixing position is apart from the developing device in the image forming units An elevating mechanism that elevates along the elevating direction intersecting the aligned direction ;
It is attached to the charging device side of the housing of the developing device and a portion approaching the photoconductor, and in contact with the surface of the photoconductor when the photoconductor is in the regular mounting position, and A film-like member spaced from the surface of the photoconductor in a state where the photoconductor is located at the retracted position;
The image forming apparatus, wherein the film-like member is attached so as to be inclined toward the developing roll side with respect to the ascending / descending direction when contacting the surface of the photoreceptor.

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