JP2008058405A - Image forming apparatus and process unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process unit for an image forming apparatus which is easy to assemble and wherein a photoreceptor drum and a developing roller can surely be positioned. <P>SOLUTION: The process unit 5 includes a photoreceptor unit 7 having the photoreceptor drum and a housing 301 supporting it, a developing unit 6 having the developing roller 33 and a housing 201 supporting it, and a positioning member 304 which positions the photoreceptor drum 12 and developing roller 33. The housing 301 of the photoreceptor unit 7 has a pressed surface 307 and the housing 201 of the process cartridge 5 has a rotatable holder 265. The holder 265 has a holder main body 271 which freely rotates on the housing 301 and a spring 275 which energizes a pressing member 277. The holder main body 271 is fixed to the housing 201 by a fixing bolt 27 not to rotate while the pressing member 277 is pressed against the pressed surface 307 by the spring 275. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a configuration of an image forming apparatus such as a printer, a facsimile, or a copier that forms an image such as a character or a graphic on a recording medium such as paper. The present invention also relates to a process unit configuration used in such an image forming apparatus.

This type of image forming apparatus is disclosed in Patent Document 1, for example. The image forming apparatus of Patent Document 1 includes a unit accommodating portion (recording portion), and is configured so that a photosensitive unit provided with a photosensitive drum and a developing unit provided with a developing roller are respectively mounted. The body frame is provided with an opening for mounting both units, and a lid member capable of opening and closing the opening. When the lid member is closed, the lid member pushes the photoreceptor unit, and the position regulating member pushes the developing unit in conjunction with the closure of the lid member. As a result, each of the photosensitive unit and the developing unit is positioned with respect to the unit housing portion, and as a result, the photosensitive drum and the developing roller are positioned so as to contact each other.
JP 2004-54082 A

  The configuration of Patent Document 1 is a configuration in which the photosensitive unit and the developing unit are mounted on the apparatus, respectively. For example, when the photosensitive drum and the developing unit are removed from the main body for maintenance, they are integrally handled. However, there is still room for improvement in terms of ease of conveyance and the like.

  Also, since the photosensitive drum and the developing roller are positioned relative to each other by positioning the photosensitive unit and the developing unit with respect to the apparatus, better positioning accuracy than when both units are directly positioned. It was difficult to realize.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, a process unit of an image forming apparatus having the following configuration is provided. That is, a photosensitive drum, a photosensitive frame that supports the photosensitive drum, a developing roller for developing toner on the electrostatic latent image on the photosensitive drum, a developing frame that supports the developing roller, and the developing the photosensitive drum A positioning member for positioning with respect to the roller. One of the developing frame and the photosensitive frame is provided with a pressed surface, and the other frame is provided with a holder so as to be rotatable. The holder includes a holder main body that is rotatably supported with respect to the other frame, a pressing member that can contact the pressed surface, and a biasing member that is disposed between the holder main body and the pressing member. And comprising. The holder body is fixed to the other frame by the fixing means so as not to be rotatable in a state where the pressing member presses the pressed surface by the biasing member.

  With this configuration, the photosensitive drum and the developing roller can be integrated and handled, so that conveyance and maintenance work can be easily performed. Further, since the photosensitive frame and the developing frame are positioned (directly) with each other by the positioning member, it is possible to improve the mutual positioning accuracy between the photosensitive drum and the developing roller. Furthermore, even if the photosensitive frame or the developing frame is distorted when the process unit is transported, the pressing member urged by the urging member presses the pressed surface, and the photosensitive drum follows the distortion. And the positional relationship between the developing roller and the developing roller can be appropriately maintained. Further, even if the resilient force of the biasing member is set large for reliable positioning, the biasing member strongly presses the pressed surface via the pressing member with a simple operation of rotating the holder. The state can be realized. Therefore, the photosensitive frame and the developing frame can be assembled in a simple and accurate positional relationship by fixing the holder so that it cannot be rotated after being adjusted.

  In the process unit of the image forming apparatus, it is preferable that the holder body has an arc-shaped long hole, and a screw member as the fixing means is disposed in the long hole.

  With this configuration, if the screw member is loosened, the holder can be freely rotated within the range of the length (angle) of the long hole. On the other hand, by tightening the screw member, the holder can be easily fixed so as not to rotate. Therefore, the assembly / separation of the photosensitive frame and the development frame can be easily performed.

  In the process unit of the image forming apparatus, a spring accommodating hole is formed in the holder main body, a spring as the biasing member is disposed in the spring accommodating hole, and the pressing portion is pressed to the opening of the spring accommodating hole. It is preferable that the members are arranged.

  With this configuration, a simple configuration in which the pressing member is urged by the spring is realized. Further, since the spring can be housed and protected in the spring housing hole, a stable pressing operation of the pressing member can be obtained, and reliable positioning can be realized.

  In the process unit of the image forming apparatus, the spring is a coil spring, and a fitting protrusion is formed on the bottom of the spring accommodating hole and the pressing member, and the fitting protrusion is an end portion of the spring. It is preferable that it is fitted inside.

  With this configuration, the spring and the pressing member can be held so as not to fall out of the holder body simply by fitting the fitting protrusion into the coil spring. Therefore, the structure of the holder can be simplified.

  The process unit of the image forming apparatus is preferably configured as follows. That is, one of the developing frame and the photosensitive frame is rotatably supported with respect to the other via a rotating shaft. The pivot shaft is detachable from the other frame.

  With this configuration, the photosensitive drum and the developing roller can be reliably and accurately positioned at the two points of the rotation shaft and the positioning member. Even if the structure is distorted when the process unit is transported, one frame rotates around the rotation axis to properly follow the distortion and maintain the positional relationship between the photosensitive drum and the developing roller. it can.

  According to another aspect of the present invention, there is provided an image forming apparatus provided with the process unit detachably.

  With this configuration, when removed from the image forming apparatus for inspection or the like, the photosensitive drum and the developing roller can be easily handled as an integrated process unit. In addition, since the positioning of the photosensitive drum and the developing roller is reliably and stably realized, it is possible to provide an image forming apparatus with good image quality.

  Next, the image forming apparatus of this embodiment will be described with reference to the drawings. 1 is an external perspective view of a copy facsimile multifunction peripheral according to an embodiment of the present invention, FIG. 2 is a front sectional view showing the inside of the main body of the multifunction peripheral, and FIG. 3 is a front sectional view showing the state of an image forming unit in detail. It is an enlarged view. FIG. 4 is an external perspective view showing the overall configuration of the process cartridge, and FIG. 5 is an explanatory view seen from the direction A in FIG. 4 showing a state in which the photosensitive unit is supported by the developing unit. FIG. 6 is an explanatory view showing a state in which the photosensitive unit is rotated from the state of FIG. 5 to position the developing roller and the photosensitive drum, and the holder is rotated. FIG. 7 is an enlarged view of a main part showing the state of FIG. 6 in detail.

  As shown in the external perspective view of FIG. 1, a copy facsimile multifunction peripheral 501 as an image forming apparatus instructs an image reading unit 511 functioning as a flatbed scanner and an auto document feed scanner, the number of copies, a facsimile transmission destination, and the like. An operation panel 512, a main body 513 including an image forming unit that forms an image on a sheet as a recording medium, and a sheet feeding cassette 514 that sequentially supplies the sheet.

  The copy facsimile multifunction peripheral 501 includes a front cover 521 on the front side of the main body 513 (the side on which the operation panel 512 is provided) and a jam access cover 522 on one side surface. The front cover 521 and the jam access cover 522 are provided so as to be openable and closable. For example, when performing maintenance work, the inside of the main body 513 can be accessed by opening the covers 521 and 522.

  The inside of the main body 513 of the copy facsimile multifunction machine 501 is shown in FIG. As shown in FIG. 2, a paper feed cassette 514 that supplies paper 100 is provided below the main body 513. This paper feed cassette 514 is configured to be able to be pulled out to the front side of the apparatus (the front side of the paper in FIG. 2). An image forming unit 11 is disposed above the paper feed cassette 514, and a fixing unit 91 and a paper discharge tray 515 are provided above the image forming unit 11.

  Inside the main body 513, a transport path 531 for transporting the paper 100 from the paper feed cassette 514 to the paper discharge tray 515 is formed. The conveyance path 531 extends upward from one end side of the paper feed cassette 514 to the image forming unit 11, further extends upward, passes through the fixing unit 91, and then curves in the horizontal direction to be discharged in the paper discharge tray 515. It is configured to reach the top. Although not shown in FIG. 2, the image reading unit 511 and the operation panel 512 are disposed above the paper discharge tray 515.

  The paper feed cassette 514 is formed to be open upward, and a plate-like flapper 532 is rotatably provided at the bottom. A plurality of sheets 100 are stacked on the flapper 532. A paper feed roller 21 is disposed above the flapper 532. Then, the paper feed roller 21 is driven while pushing up the flapper 532 upward by a biasing spring (not shown), whereby the uppermost paper 100 is separated and picked up and sent out toward the transport path 531. .

  A separation roller 22 is disposed immediately downstream of the paper feed roller 21 in the transport path 531. The separation roller 22 is driven while the paper 100 is nipped between the rollers arranged opposite to the roller, and separates the paper 100 one by one. A registration roller 23 is disposed on the downstream side of the separation roller 22. The registration roller 23 is driven while the paper 100 is nipped between the registration roller 23 and a roller disposed opposite to the registration roller 23, thereby conveying the paper 100 to the downstream image forming unit 11 while correcting the skew of the paper 100.

  As shown in FIG. 2 and FIG. 3, which is an enlarged view of a main part thereof, the image forming unit 11 includes a charger 13, an LED head 14, a developing device 15, a transfer roller 16, around the photosensitive drum 12. The cleaner 17 is arranged.

  The photosensitive drum 12 is configured such that a photoconductive film made of an organic photoreceptor is formed on the surface and is rotated by an electric motor (not shown). The charger 13 is configured as a non-contact corona charging type so-called scorotron charger, and the surface of the photosensitive drum 12 is uniformly charged, for example, negatively by the charger 13.

  The LED head 14 as an exposure device is disposed downstream of the charger 13 (refers to the downstream side in the rotation direction of the photosensitive drum 12. Hereinafter, the same applies to the description of the developing device 15, the transfer roller 16, and the cleaner 17). In this configuration, a large number of light emitting diodes (LEDs) are arranged in the paper width direction. A lens array in which a large number of gradient index lenses are arranged is disposed on the surface of the LED head 14. The LED head 14 selectively emits light corresponding to the image data of the facsimile original received via the telephone line or the image data read by the image reading unit 511. As a result, the surface of the photosensitive drum 12 is selectively exposed, and the electrostatic energy is formed by losing the charge energy of the exposed portion.

  The developing device 15 is disposed on the downstream side of the LED head 14. The developing device 15 is configured in a two-component developing system that uses toner and carrier as developers. Specifically, the developing device 15 includes a developer container 35 made of synthetic resin, two screw-shaped stirring members 31 and 32 disposed inside the developer container 35, and a slight amount relative to the photosensitive drum 12. A developing roller 33 as a developer carrier supported by the developer container 35 and a regulating blade 34 disposed in the vicinity of the surface of the developing roller 33. I have.

  The agitating members 31 and 32 are driven to rotate, whereby the two-component developer is circulated in the developer container 35 while uniformly mixing the toner and the carrier. The developing roller 33 is formed of a non-magnetic material in a cylindrical shape, and is rotatably fitted to the outside of the cylindrical magnetic body 36. The internal magnetic body 36 attracts the two-component developer to the surface of the developing roller 33 by the magnetism, and the two-component developer is held on the surface of the developing roller 33 by rotating the developing roller 33 in this state. Then, it is sent to the photosensitive drum 12 side. Note that the thickness of the two-component developer on the surface of the developing roller 33 is regulated to be uniform by the regulating blade 34.

  Thereafter, in the vicinity of the photosensitive drum 12 and the developing roller 33, only the portion of the two-component developer on the surface of the developing roller 33 where the toner corresponds to the exposed portion by the LED head 14 moves to the surface of the photosensitive drum 12. Move selectively. As a result, a toner image corresponding to the electrostatic latent image is formed on the surface of the photosensitive drum 12. Of the two-component developer, the remaining toner that has not moved to the carrier and the photosensitive drum 12 is collected in the developer container 35.

  The transfer roller 16 is disposed on the downstream side of the developing device 15 and is disposed on the opposite side of the photosensitive drum 12 with the conveyance path 531 interposed therebetween. A predetermined voltage from a power source is applied to the transfer roller 16. Accordingly, the toner image formed on the surface of the photosensitive drum 12 moves so as to approach the transfer roller 16 side by the rotation of the photosensitive drum 12, and is transferred to the paper 100 by the electric field attraction force.

  The cleaner 17 is disposed on the downstream side of the transfer roller 16 and is configured to scrape and store residual toner that has not been transferred to the paper 100 at the transfer roller 16 portion from the surface of the photosensitive drum 12. .

  Of the configuration of the image forming unit 11, at least the photosensitive drum 12, the charger 13, the developing device 15 (including the developing roller 33), and the cleaner 17 are integrated as a process cartridge (process unit) 5. Composed. The process cartridge 5 is detachably attached to the image forming unit 11. When the developer in the developing unit 15 runs out or the photosensitive drum 12 reaches the end of its life, the process cartridge 5 is removed from the copy facsimile multifunction machine 501. Can be exchanged for new ones. The sheet 100 on which the toner image is transferred in the image forming unit 11 is sent to the fixing unit 91 on the downstream side of the conveyance path 531 by the rotation of the photosensitive drum 12.

  As shown in FIGS. 2 and 3, the fixing unit 91 includes a heat roller 92 that incorporates a heat source (such as a halogen lamp) and is driven to rotate, and a press roller 93 that is disposed to face the heat roller 92. It is equipped with. The press roller 93 is pressed against the heat roller 92 by a biasing spring (not shown). With this configuration, when the paper 100 passes between the heat roller 92 and the press roller 93, the toner of the toner image is melted and fixed to the paper 100 by the heat of the high-temperature heat roller 92 and the pressure by the press roller 93. The fixing unit 91 is provided with a separation claw 94 for preventing the paper 100 from being wrapped around the heat roller 92 while being stuck.

  As shown in FIG. 2, a conveyance roller 95 is provided on the downstream side of the fixing unit 91, and a paper discharge roller 96 is provided on the further downstream side. With this configuration, the sheet 100 sent from the fixing unit 91 is nipped between the transport roller 95 and the driven roller disposed opposite thereto, and is sent downstream. Further, the paper 100 is nipped between the paper discharge roller 96 and a driven roller disposed opposite thereto, and is discharged onto the paper discharge tray 515.

  Next, the process cartridge 5 will be described with reference to FIG. As shown in FIG. 4, which is an external perspective view, the process cartridge 5 is configured by combining a developing unit 6 that stores a developing unit 15 (developing roller 33) and a photosensitive unit 7 that stores the photosensitive drum 12. Has been.

  The developing unit 6 includes a housing (developing frame) 201 made of synthetic resin, and supports the developing roller 33 rotatably therein. As shown in FIG. 3, the housing 201 is configured to also serve as the developer container 35 in the developing device 15.

  Bearings 262 that rotatably support the developing roller 33 are disposed in the housing 201 at positions at both ends in the axial direction of the developing roller 33. Further, the housing 201 is formed with an elongated opening 202 as shown in FIG. 4, so that the LED head 14 provided on the main body 513 side can be inserted from the opening 202 (see FIG. 3). .

  The photosensitive unit 7 includes a synthetic resin housing (photosensitive frame) 301 and rotatably supports the photosensitive drum 12 therein. The housing 301 is configured to also serve as a storage container for residual toner in the cleaner 17.

  On both side surfaces of the housing 301, round bar-shaped protrusions (rotating shafts) 302 are provided. An insertion groove 261 is formed in the housing 201 of the developing unit 6 at a position corresponding to the protrusion 302. By inserting the protrusion 302 into the insertion groove 261, the housing 301 of the photosensitive unit 7 can be rotatably supported by the housing 201 of the developing unit 6. Further, by removing the protrusion 302 from the insertion groove 261, the photosensitive unit 7 can be detached from the developing unit 6 and separated.

  A positioning member 304 is fitted to the central shaft 303 of the photosensitive drum 12, and a contact surface 305 is formed at one end of the positioning member 304. With this configuration, when the developing device unit 6 and the photosensitive unit 7 are assembled, the contact surface 305 of the positioning member 304 contacts the outer peripheral surface of the bearing 262 that pivotally supports the development roller 33, so that the development roller 33. In contrast, the photosensitive drum 12 can be accurately positioned.

  As shown in FIG. 5, which is a view of the process cartridge 5 as viewed from the direction A in FIG. 4, a cylindrical convex portion 306 is formed in the vicinity of the central shaft 303, and an outer peripheral surface (upper surface) of the convex portion 306 is formed. ) Is a pressed surface 307. The pressed surface 307 can be pressed by a pressing member 277 of a holder 265 described later.

  Further, a boss portion 263 projects from the housing 201 of the developing unit 6, and a holder 265 is attached to the boss portion 263. Specifically, the boss portion 263 is formed in a columnar shape, and a circular shaft hole is formed in the holder main body 271 of the holder 265. By fitting the shaft hole into the boss portion 263, A holder 265 is rotatably supported with respect to the housing 201.

  The holder main body 271 includes a concave portion 272 having a size that allows the convex portion 306 to be inserted, and a spring accommodating hole 273 is formed in the vicinity of the concave portion 272. The spring accommodating hole 273 is disposed so as to form an opening on the concave portion 272 side. A cross rib 274 protrudes from the bottom of the spring accommodating hole 273, and a spring (biasing member) 275 is disposed inside the spring accommodating hole 273. The spring 275 is formed in a coil spring shape, and the cross rib 274 is fitted inside one end thereof.

  A pressing member 277 is disposed at the opening of the spring accommodating hole 273. The pressing member 277 is configured to be able to contact the pressed surface 307 of the convex portion 306. Further, a cross rib (fitting protrusion) 276 protrudes from the surface of the pressing member 277 facing the spring accommodating hole 273, and inside the end of the spring 275 on the opening side of the spring accommodating hole 273, The cross rib 276 is fitted.

  In the present embodiment, the dimensions of the cross ribs 274 and 276 are set slightly larger than the inner diameter of the spring 275, and the spring 275 is wound around the outer surface of the cross ribs 274 and 276 and tightened, whereby the pressing member 277, The spring 275 and the holder main body 271 are assembled so as not to fall apart. However, a stopper for restricting the removal of the spring 275 and the dropping of the pressing member 277 may be provided in the spring accommodating hole 273, for example.

  Further, a long hole 278 is formed in the holder body 271. The elongated hole 278 is formed in an arc shape centering on the rotation center of the holder 265 (the boss portion 263). A shaft portion of a fixing bolt (screw member) 279 as a fixing means is inserted into the long hole 278, and the fixing bolt 279 is not shown in the screw hole formed in the housing 201 of the developing unit 6. Are screwed together.

  A process of assembling the process cartridge 5 by assembling the developing unit 6 and the photosensitive unit 7 with the above configuration will be described. FIG. 5 shows a state in which the protrusion 302 on the photosensitive unit 7 side is inserted into the insertion groove 261 on the developer unit 6 side. At this time, the housing 301 of the photosensitive unit 7 is rotatable around the protrusion 302 with respect to the housing 201 of the developing unit 6.

  When the housing 301 of the photosensitive unit 7 is lowered from the state shown in FIG. 5, the contact surface 305 of the positioning member 304 on the photosensitive unit 7 side comes into contact with the outer peripheral surface of the bearing 262 on the developing unit unit 6 side. As a result, the photosensitive drum 12 and the developing roller 33 are accurately positioned so as to have a predetermined inter-axis distance.

  In this state, the holder 265 is rotated counterclockwise in FIG. 5 within the range of the length (angle) of the long hole 278 (note that the fixing bolt 279 is loosened in advance so that the holder 265 can be rotated). To keep). Then, as shown in FIG. 6, the concave portion 272 of the holder main body 271 moves to the position of the convex portion 306, and the pressing member 277 contacts the pressed surface 307 of the convex portion 306. When the holder 265 is further rotated, the spring 275 is compressed, so that the pressing member 277 presses the pressed surface 307 with the repulsive force of the spring 275. As a result, the housing 301 of the photosensitive unit 7 is pushed counterclockwise in FIG. 6, so that the contact surface 305 of the positioning member 304 is securely in contact with the bearing 262.

  Then, in the state where the spring 275 is compressed, the fixing bolt 279 is tightened to fix the holder 265 so as not to rotate. By doing so, the spring force of the spring 275 always acts on the housing 301 of the photosensitive unit 7, and the contact surface 305 of the positioning member 304 is always pressed against the bearing 262. Therefore, the positional relationship between the photosensitive drum 12 and the developing roller 33 is reliably maintained so as to be a predetermined position.

  Since the developing unit 6 and the photosensitive unit 7 constituting the process cartridge 5 have different lifetimes, for example, there are cases where only one of the developing unit 6 or the photosensitive unit 7 needs to be repaired or replaced. In this case, the fixing bolt 279 is loosened to release the pressing of the convex portion 306 by the pressing member 277, the holder 265 and the housing 301 of the photosensitive unit 7 are slightly rotated, and then the protrusion 302 is removed from the insertion groove 261. It ’s fine. By doing so, the developing unit 6 and the photosensitive unit 7 can be separated from each other, and maintenance work can be easily performed.

  As described above, the process cartridge 5 of the copy facsimile multifunction peripheral 501 of this embodiment includes the photosensitive drum 12, the housing 301 (on the photosensitive unit 7 side) that supports the photosensitive drum 12, and the electrostatic capacitance of the photosensitive drum 12. A developing roller 33 for developing the latent image with toner and a housing 201 (on the side of the developing unit 6) that supports the developing roller 33 are provided, and the photosensitive drum 12 is positioned with respect to the developing roller 33. Positioning member 304 is provided. The housing 301 of the photosensitive unit 7 includes a pressed surface 307, and the housing 201 of the developing unit 6 includes a holder. The holder 265 is disposed between a holder main body 271 that is rotatably supported by the housing 201, a pressing member 277 that can contact the pressed surface 307, and the holder main body 271 and the pressing member 277. And a spring 275 to be provided. The holder 265 is non-rotatably fixed to the housing 201 of the developing unit 6 by a fixing bolt 279 in a state where the pressing member 277 presses the pressed surface 307 by a spring 275.

  As a result, the photosensitive unit 7 and the developing unit 6 can be handled as an integrated process cartridge 5, so that conveyance and maintenance work can be easily performed. Further, since the photosensitive unit 7 and the developing unit 6 are directly positioned with respect to each other by the positioning member 304, the mutual positioning accuracy between the photosensitive drum 12 and the developing roller 33 can be improved. Further, even if the photosensitive unit 7 and the developing unit 6 are distorted due to an impact applied when the process cartridge 5 is conveyed, the pressing member 277 biased by the spring 275 causes the pressed surface 307 of the convex portion 306 to be pressed. By pressing, the positional relationship between the photosensitive drum 12 and the developing roller 33 can be appropriately maintained following the distortion. Furthermore, even if the spring force of the spring 275 is set to be large in order to perform positioning reliably by pressing the positioning member 304 with a strong force, the spring 275 causes the pressing member 277 to be moved by a simple operation of rotating the holder 265. Thus, it is possible to realize a state in which the pressed surface 307 is pressed strongly. Specifically, when the process cartridge 5 is assembled, the entire holder 265 is simply rotated around the boss portion 263, the pressing member 277 is pressed against the pressed surface 307 of the convex portion 306, the spring 275 is compressed, and the spring 275 is compressed. The housing 301 of the photosensitive unit 7 can be pressed counterclockwise in FIG. 6 (FIG. 7) by a strong reaction force. Accordingly, it is possible to reduce the number of manufacturing steps and the time required for assembly of the process cartridge 5.

  In order to obtain a pressing force for positioning, protrusions are provided on each of the housing 301 of the photosensitive unit 7 and the housing 201 of the developing unit 6, and both ends of the extended spring are engaged with the protrusions. A configuration in which the positioning member 304 is pressed against the outer peripheral surface of the bearing 262 by the tensile force of the spring is also conceivable. However, since the spring often has a large spring force for improving positioning accuracy, in the above configuration, the end of the spring is gripped with a tool such as pliers at the time of assembly to resist the large spring force. Therefore, it is difficult to engage with the protrusions while stretching, leading to a decrease in the efficiency of the assembly work. In this respect, in the configuration using the holder 265 of the present embodiment, even if a spring 275 having a large spring force is used, the spring 275 is compressed by simply holding and rotating the holder 265, and the fixing bolt is fixed in that state. Since it can be fixed using 279, the assembly workability is very good.

  In the present embodiment, the holder main body 271 includes an arc-shaped elongated hole 278, and a fixing bolt 279 is disposed in the elongated hole 278, and the holder 265 is fixed by the fixing bolt 279 so as not to rotate. It has become.

  As a result, it is possible to easily switch between the non-rotatable / unrotatable state of the holder 265 by a simple operation of tightening or loosening the fixing bolt 279. Therefore, assembly / separation of the developing unit 6 and the photosensitive unit 7 can be easily performed.

  In this embodiment, the holder main body 271 is formed with a spring accommodation hole 273, the spring 275 is disposed in the spring accommodation hole 273, and the pressing member 277 is formed in the opening of the spring accommodation hole 273. Is arranged.

  Thereby, a simple configuration in which the pressing member 277 is urged by the spring 275 is realized. Further, since the spring 275 can be housed and protected in the spring accommodating hole 273, a stable pressing operation of the pressing member 277 can be obtained, and reliable positioning can be realized.

  In the present embodiment, the spring 275 is a coil spring, and cross ribs 274 and 276 are formed at the bottom of the spring accommodating hole 273 and the pressing member 277, and the cross ribs 274 and 276 are formed on the spring 275. It is fitted so as to be inserted into the end portion.

  Thereby, the spring 275 and the pressing member 277 can be held with respect to the holder main body 271 with a simple configuration, and the manufacturing cost can be reduced.

  In this embodiment, the housing 301 of the photosensitive unit 7 is rotatably supported with respect to the housing 201 of the developing unit 6 via the protrusions 302. The projection 302 is configured to be detachable from the housing 201 of the developing unit 6.

  As a result, the projection 302 and the contact surface 305 of the positioning member 304 can be reliably and accurately positioned. Further, for example, even if the structure is distorted due to an impact or the like when the process cartridge 5 is transported, the photosensitive unit 7 appropriately rotates to follow the distortion by rotating around the protrusion 302, and the developing roller 33. The positional relationship with the photosensitive drum 12 can be appropriately maintained. Further, by removing the protrusion 302 from the housing 201 of the developing unit 6, the developing unit 6 and the photosensitive unit 7 can be easily separated.

  Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.

  The positioning member 304 can be changed so as to be integrally formed with the housing 301 of the photosensitive unit 7, for example. Further, the position can be changed so as to contact with any other member instead of the bearing 262 on the developing device unit 6 side. Further, the positioning member can be changed to be provided not on the photosensitive unit 7 side but on the developing device unit 6 side.

  The protrusions formed in the spring accommodating hole 273 and the pressing member 277 can be formed in other shapes such as a columnar shape in addition to the cross ribs 274 and 276. Further, instead of the coil spring-like spring 275, a torsion coil spring-like one or an elastic member such as rubber can be employed.

  The protrusion 306 (the pressed surface 307) can be provided in the housing 201 on the developing unit 6 side, and the holder 265 can be provided in the housing 301 on the photosensitive unit 7 side.

  Instead of providing the protrusion 302 on the photosensitive unit 7 side and providing the insertion groove 261 on the developing unit unit 6 side, a modification may be made such that a protrusion is provided on the developing unit unit 6 side and an insertion groove is provided on the photosensitive unit side. it can.

  Instead of positioning so as to form a small gap between the photosensitive drum 12 and the developing roller 33, it is possible to change the positioning so that both are in contact with each other.

  The configuration of the present invention can be applied to, for example, a printer, a copier, a facsimile machine, and the like instead of the copy facsimile multifunction machine 501.

1 is an external perspective view of a copy facsimile multifunction peripheral according to an embodiment of the present invention. FIG. 3 is a front cross-sectional view showing the inside of the main body of the multifunction machine. The front cross-sectional enlarged view which shows the mode of an image formation part in detail. FIG. 2 is an external perspective view showing an overall configuration of a process cartridge. FIG. 5 is an explanatory diagram viewed from the direction A in FIG. 4 showing a state in which the photosensitive unit is supported by the developing unit. FIG. 6 is an explanatory diagram illustrating a state in which the photosensitive unit is rotated from the state of FIG. 5 to position the developing roller and the photosensitive drum, and the holder is rotated. The principal part enlarged view which shows the state of FIG. 6 in detail.

Explanation of symbols

5 Process cartridge (process unit)
6 Developing Unit 7 Photosensitive Unit 11 Image Forming Unit 12 Photosensitive Drum 33 Developing Roller 201 Housing (Developing Frame)
265 Holder 271 Holder body 272 Recess 273 Spring accommodating hole 274 Cross rib 275 Spring (biasing member)
276 Cross rib (fitting protrusion)
277 Press member 278 Long hole 279 Fixing bolt (fixing means, screw member)
301 Housing (photosensitive frame)
302 Protrusion (rotating shaft)
304 Positioning member 306 Projection 307 Pressed surface 501 Copy facsimile multifunction peripheral (image forming apparatus)

Claims (6)

A photosensitive drum;
A photosensitive frame that supports the photosensitive drum;
A developing roller for developing toner on the electrostatic latent image on the photosensitive drum;
A developing frame that supports the developing roller;
A positioning member for positioning the photosensitive drum with respect to the developing roller;
With
One of the development frame and the photosensitive frame is provided with a pressed surface, and the other frame is rotatably provided with a holder.
The holder is
A holder main body rotatably supported with respect to the other frame;
A pressing member capable of contacting the pressed surface;
A biasing member disposed between the holder body and the pressing member;
With
The image forming apparatus according to claim 1, wherein the holder body is fixed to the other frame so as not to be rotatable by a fixing means in a state where the pressing member presses the pressed surface by the biasing member. Process unit. A process unit of the image forming apparatus according to claim 1,
A process unit of an image forming apparatus, wherein the holder body is provided with an arc-shaped long hole, and a screw member as the fixing means is disposed in the long hole. A process unit of the image forming apparatus according to claim 1,
The holder body is formed with a spring accommodating hole, a spring as the biasing member is disposed in the spring accommodating hole, and the pressing member is disposed in an opening of the spring accommodating hole. Process unit of image forming apparatus. A process unit of the image forming apparatus according to claim 3,
The spring is a coil spring, and a fitting projection is formed on the bottom of the spring accommodating hole and the pressing member, and the fitting projection is fitted inside the end of the spring. A process unit of the image forming apparatus. A process unit of the image forming apparatus according to any one of claims 1 to 4,
One of the developing frame and the photosensitive frame is supported rotatably with respect to the other via a rotating shaft,
The process unit of an image forming apparatus, wherein the rotation shaft is detachable from the other frame.   An image forming apparatus comprising the process unit according to claim 1 in a detachable manner.

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