JP3997196B2 - Process cartridge and developing separation member - Google Patents

Description

The present invention relates to a process cartridge and a developing separation member that can be attached to and detached from the process cartridge .

  Here, the electrophotographic image forming apparatus is an apparatus that forms an image on a recording medium using an electrophotographic image forming system, such as an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), A facsimile machine and a word processor are included.

  The process cartridge is a cartridge in which at least one of charging means, developing means and cleaning means and an electrophotographic photosensitive drum are integrally formed, and the cartridge can be attached to and detached from the image forming apparatus main body. is there.

  Image forming apparatuses such as copiers, laser printers, and facsimile machines selectively expose a photosensitive drum (image carrier) uniformly charged by a charging device to form an electrostatic latent image. The latent image is developed as a toner image by attaching toner with a developing device, and then the toner image is transferred to a recording agent such as paper to form an image. Then, the toner remaining on the surface of the image carrier after the transfer of the toner image is removed by a cleaning device and used for the next image forming apparatus.

  In recent years, a photosensitive cartridge having a photosensitive image carrier, a charging device, a developing device, a cleaning device, and the like integrated into a cartridge container as a process cartridge is known. The process cartridge is configured to be detachable from the main body of the image forming apparatus. When the user mounts the process cartridge on the main body of the image forming apparatus, the user can easily supply toner and replace the photosensitive drum with confidence. It is possible to make maintenance easier.

  Further, in recent years, independent developing devices for yellow, magenta, cyan, and black are selectively disposed on the photosensitive drum to perform a developing operation, or are fixedly disposed on the photosensitive drum and are respectively disposed. An image forming apparatus for forming a multicolor image by selectively driving a developing device has been devised, and a process cartridge used for the multicolor image forming apparatus has been put into practical use.

  Here, as the charging device in the above-described process cartridge, a non-contact method using corona discharge and a contact method using a charging roller are generally used, but in recent years, the latter is used for the purpose of preventing ozone generation. The contact method is generally used.

  However, if the above-described contact-type charging device is left in contact with the photosensitive drum for a long period of time, a portion of the charging member (for example, a charging roller) that contacts the photosensitive drum will be removed. It may cause permanent deformation and change in charging ability, resulting in image defects such as density unevenness. Also on the surface of the photosensitive drum, the photosensitive drum and the charging member rub against each other due to vibrations when the process cartridge is transported, and a history remains as a charging memory, which may cause image defects such as density unevenness. Therefore, when image formation is not performed, it is better to reduce the contact pressure between the charging member and the photosensitive drum. For the same reason, it is preferable that the developer carrying member and the photosensitive drum that are in contact with each other when the image is formed are not in contact with each other when the image is not formed.

  Here, as a means for solving the above problem, a spacer member is conventionally provided in an area (non-image forming area) between the surface of the photosensitive drum and the charging member and outside the area (image forming area) where an image is written. A method of holding the two in an unused state (especially during transport) (see, for example, Patent Document 1), a method of performing pressure separation using a solenoid (see, for example, Patent Document 2), etc. Is disclosed. Further, by connecting one end of the toner seal to this spacer member, a configuration is disclosed in which the toner seal is unsealed and the spacer is removed at one time to reduce the user's work and less burden is imposed (for example, Patent Document 3). Yes. However, in the method in which the spacer member is sandwiched between the photosensitive drum and the charging member, even in the non-image forming region, the photosensitive drum, the charging member, and the spacer member are rubbed to change the surface state, and the contact between them changes. End up. In addition, when separating using a solenoid, it is necessary to newly provide a complicated circuit. Also, a strong force is required to simultaneously open the toner seal and remove the spacer.

Further, when trying to separate the developer carrying member and the photosensitive drum as well as the charging member and the photosensitive drum, there are problems that the number of parts increases, the cost increases, and the usability deteriorates.
JP-A-2-39169 JP-A-6-316349 JP 2001-201914 A

  The present invention provides a process cartridge and an image forming apparatus in which the above-described method is improved and the charging means can be moved in the contact and separation direction from the image carrier without increasing the burden on the user with a simple configuration. It is intended.

The present invention is for solving the above problems,
An image carrier;
Charging means for charging the image carrier in contact with the image carrier;
In a process cartridge detachable from the image forming apparatus main body,
A first frame for holding the image carrier rotatably and holding the charging means movably in a contact and separation direction with respect to the image carrier;
A developer carrying member carrying a developer for developing an electrostatic latent image formed on the surface of the image carrying member;
A second frame that is movable with respect to the first frame and provided with the developer carrier;
A biasing member that biases the first frame and the second frame to bring the developer carrier and the image carrier into contact with each other;
When the developing separation member is mounted on the process cartridge, the developing separation member moves the first frame and the second frame against the urging force of the urging member to move the developer. The charging unit and the image carrier when the carrier and the image carrier are separated from each other and the charging unit and the image carrier are separated from each other or when the developing separation member is mounted on the process cartridge. And keep it weaker than the contact pressure with
When the developing separation member is removed from the process cartridge, the developer carrier and the image carrier are in contact with each other, and the charging member and the image carrier are in contact with each other. is there.

As an effect of the present invention , since the charging member can be positioned by a member that separates the developer carrier, each contact / separation state can be set without using a plurality of members.

  Examples will be described below.

[Overall Description of Image Forming Apparatus]
First, the overall configuration of the color image forming apparatus will be schematically described with reference to FIG.

  FIG. 1 is an explanatory diagram of the overall configuration of a laser printer which is an embodiment of a color image forming apparatus.

  As shown in FIG. 1, the color laser printer has an image that rotates at a constant speed for each color, Y (yellow), M (magenta), C (cyan), Bk (black) (the subscripts of the numbers represent the colors below). An image forming unit having process cartridges 2Y, 2M, 2C, and 2Bk having a carrier (photosensitive drum) 21 and a transfer material that is developed in the image forming unit and held in multiple transfer and is fed from the feeding unit The intermediate transfer member 35 further transfers to P, the fixing unit 50 that fixes the color image to the transfer material P to which the color image is transferred, and a discharge roller group 53.45.55 that discharges the transfer material P onto the discharge tray 56 on the upper surface of the apparatus. . The four-color process cartridges 2 are individually detachable from the printer body. Here, the process cartridge is a product in which at least one of charging means, developing means, and cleaning means and an electrophotographic photosensitive drum are integrally formed into a cartridge, and the cartridge can be attached to and detached from the image forming apparatus main body. It is.

  Next, the configuration of each part of the image forming apparatus will be sequentially described in detail.

[Image carrier]
The photosensitive drum 21 (21Y, 21M, 21C, 21Bk), which is an image carrier, is configured by applying an organic photoconductive layer to the outer peripheral surface of an aluminum cylinder, and rotates to the photosensitive drum frame 24 of the photosensitive drum 21. It is supported freely. In addition, by transmitting a driving force of a driving motor (not shown) to one rear end in the figure, the photosensitive drum 21 is rotated counterclockwise in the drawing according to an image forming operation.

[Charging means]
The charging means uses a contact charging system, and a conductive charging roller 23 formed in a roller shape is brought into contact with the surface of the photosensitive drum 21 and a voltage is applied to the charging roller, whereby the photosensitive drum 21 is charged. Is uniformly charged.

[Exposure means]
The image carrier 21 is exposed from the scanner unit 1 (1Y, 1M, 1C, 1Bk). When the image signal is applied to the laser diode, the laser diode irradiates the polygon mirror 11 (11Y, 11M, 11C, 11Bk) with the image light 10 corresponding to the image signal. The polygon mirror 11 is rotated at a high speed by a scanner motor 12, and the image light 10 reflected by the polygon mirror 11 selectively exposes the surface of the image carrier 21 rotating at a constant speed via the imaging lens 13, resulting in an image. An electrostatic latent image is formed on the carrier 21.

[Development means]
In order to make the electrostatic latent image visible, it is composed of four developing units capable of developing colors of yellow, magenta, cyan, and black. Each of the four color developing devices is disposed at a position facing the photoconductive drum 21 and the developing roller 22 in contact with the photoconductive drum 21 while rotating, and forms a visible image on the photoconductive drum 21 with each color toner.

[Intermediate transfer member]
The intermediate transfer member 35 rotates clockwise in the drawing in synchronization with the outer peripheral speed of the photosensitive drum 21 in order to multiplex-transfer the toner image on the photosensitive drum 21 visualized by each developing device 2 during the color image forming operation. The toner image formed on the photoconductive drum 21 is arranged at a position facing the photoconductive drum 21 with the intermediate transfer body 35 interposed therebetween, and the primary transfer roller 34 (34Y, 34M, 34C, 34Bk) to which a voltage is applied. Multiple transfer is performed on the intermediate transfer body 35 at the primary transfer portion T1 (T1Y, T1M, T1C, T1Bk) which is a contact. The intermediate transfer member 35 that has received the multiple transfer sandwiches and conveys the transfer material P by the secondary transfer roller 51 to which a voltage is applied in the secondary transfer portion T2, thereby transferring each color toner image on the intermediate transfer member 35 to the transfer material 2. Simultaneous multiple transfer.

  The intermediate transfer member (intermediate transfer belt) 35 according to this embodiment is formed of a seamless resin belt having a circumferential length of about 620 mm, and is stretched around three axes of a drive roller 31, a secondary transfer counter roller 32, and a tension roller 33. Further, both ends of the tension roller 33 are loaded with springs, and even when the peripheral length of the intermediate transfer belt 35 changes due to temperature and humidity in the main body and changes with time, the amount of change can be absorbed.

  A guide rib (not shown) made of rubber is affixed to the entire circumference of one side edge portion inside the intermediate transfer member 35 with an adhesive. Further, a flange (not shown) made of resin is disposed at one end of the tension roller 33, and a guide rib (not shown) and a flange (not shown) are connected to the traveling direction of the intermediate transfer body 35. It regulates the movement in the direction that goes straight (hereinafter referred to as “slip”).

  The intermediate transfer member 35 is supported by the main body with the driving roller 31 as a fulcrum, and the driving force of a driving motor (not shown) is transmitted to one end of the driving roller 31 at the rear of the drawing, so that the intermediate transfer member 31 is subjected to an image forming operation. It is made to rotate clockwise in the figure.

[Paper Feeder]
The sheet feeding unit feeds the transfer material P to the image forming unit. From the cassette 7 storing a plurality of transfer materials P, the sheet feeding roller 41, the separation pad 42, the sheet feeding guide 43, and the registration roller pair 44. Mainly composed. At the time of image formation, the paper feed roller 41 is driven and rotated according to the image forming operation, and the transfer material P in the cassette 4 is separated and fed one by one, guided by the paper feed guide 43, and registered via the transport roller. The roller 44 is reached. During the image forming operation, the registration roller 44 performs a non-rotating operation for causing the transfer material P to stand still and a rotating operation for conveying the transfer material P toward the intermediate transfer body 35 in a predetermined sequence, and is the next step. The image and the transfer material P are aligned in the transfer process.

[Secondary transfer section]
The secondary transfer unit is composed of a swingable secondary transfer roller 51. The secondary transfer roller 51 has a metal shaft wound with a medium-resistance foamed elastic body, is movable in the vertical direction in the figure, and has a drive. The secondary transfer roller 51 is pressed against the intermediate transfer member 35 by a cam member (not shown) at an upper position, that is, through the transfer material P at a predetermined pressure in accordance with the timing of transferring the color image to the transfer material P. At the same time, a bias is applied to the secondary transfer roller 51, and the toner image on the intermediate transfer body 35 is transferred to the transfer material P. Here, since the intermediate transfer body 35 and the secondary transfer roller 51 are respectively driven, the transfer material P sandwiched between the two is transported at a predetermined speed in the left direction in the drawing at the same time as the transfer process is performed. Then, the toner is conveyed by the conveying belt 52 toward the fixing device 50 which is the next process.

[Fixing part]
The fixing unit 50 fixes the toner image formed on the transfer material P via the intermediate transfer body 35 with the toner image formed by the developing means, and includes a ceramic heater 63 for applying heat to the transfer material P. It comprises a built-in film guide unit 61 and a pressure roller 62 for pressing the transfer material P against the film guide unit 61. That is, the transfer material P holding the toner image is conveyed by the film guide unit 61 and the pressure roller 62, and the toner is fixed to the transfer material P by applying heat and pressure.

[Image forming operation]
Next, an operation when image formation is performed by the apparatus configured as described above will be described.

  First, the sheet feeding roller 41 shown in FIG. 1 is rotated to separate one sheet of the transfer material P in the sheet feeding cassette 7 and conveyed to the registration roller 44.

  On the other hand, the photosensitive drum 21 and the intermediate transfer member 35 rotate in the direction indicated by the arrow at a predetermined outer peripheral speed V (hereinafter referred to as a process speed).

  The photosensitive drum 21 whose surface is uniformly charged by the charging roller 23 is subjected to laser 10 exposure to form an image.

  Since the image forming operation for each color is the same, a yellow image will be described here.

Yellow Image Formation A yellow image is formed on the photosensitive drum 21Y by irradiating the laser image 10Y of the yellow image with the scanner unit 1Y. Simultaneously with the formation of the latent image, the yellow developing unit 22Y is driven to apply a voltage having the same polarity as the charging polarity of the photosensitive drum 21Y so that yellow toner adheres to the latent image on the photosensitive drum 21Y. Develop. At the same time, the yellow toner image on the photosensitive drum 21Y is primarily transferred onto the outer periphery of the intermediate transfer member 35 at the first transfer position T1Y downstream of the developing position . At this time, primary transfer is performed by applying a voltage having a reverse characteristic to that of the yellow toner to the intermediate transfer member 35.

  In the same manner as described above, magenta, cyan, and black images are formed, and latent image formation, development, and toner transfer to the intermediate transfer body 35 are performed in the order of yellow, magenta, cyan, and black, respectively, at primary transfer positions T1Y, T1M, and T1C. , T1K, and a full-color image composed of four types of toners of yellow, magenta, cyan, and black is formed on the surface of the intermediate transfer member 35.

  Before the transfer of the black toner to the intermediate transfer body 35 is completed, that is, before the leading edge of the intermediate transfer body 35 that has formed the full color image after the primary transfer of the black toner of the fourth color reaches the second transfer portion T2. In addition, the transfer material P that has been waiting by the above-described registration roller 44 is transported at the same timing. At the time of image formation of each color on the four-color intermediate transfer member 35, the secondary transfer roller 51, which waits downward and is not in contact with the intermediate transfer member 35, is simultaneously moved upward by a cam (not shown). The transfer material P is brought into pressure contact with the second transfer portion T2 of the intermediate transfer body 35, and at the same time, a bias having a characteristic opposite to that of the toner is applied to the secondary transfer roller 51, whereby the full color image on the intermediate transfer body 35 is applied to the transfer material P all at once. Transfer four colors simultaneously. The transfer material P that has passed through the second transfer portion T2 is peeled off from the intermediate transfer body 35, conveyed to the fixing portion 50, and after toner fixing, the image is transferred onto the discharge tray 56 at the top of the main body via the discharge roller pairs 53, 54, and 55. The sheet is discharged with the surface facing downward, and the image forming operation is completed.

  FIG. 4 is a schematic cross-sectional view illustrating a state when the opening / closing cover of the image forming apparatus is opened.

  The main body opening / closing cover 14 has a center of rotation at the lower front side of the color image forming apparatus A. Since the intermediate transfer member 35 is provided on the opening / closing cover 14 side, the process cartridges 2Y, 2M, 2C, 2Bk can be accessed by opening the opening / closing cover 14.

  Reference numeral 101 denotes a CRG holding plate that integrally holds the process cartridges 2Y, 2M, 2C, and 2Bk. A pivot point of the CRG holding plate 101 is provided above the apparatus, and is connected to the opening / closing cover 14 by a link mechanism described later. As a result, when the opening / closing cover 14 is opened, the CRG holding plate 101 and the process cartridges 2Y, 2M, 2C, and 2Bk are rotated about the pivot point so as to be held at a predetermined angle. In this embodiment, the angle at this time is about 45 degrees.

  In this state, there is no obstruction when the process cartridge is attached and detached in the direction of the arrow in the figure, and the operation becomes easy.

  I will explain in more detail.

  FIG. 2 is a schematic perspective view showing the periphery of the process cartridge held by the CRG holding plate. For convenience of explanation, the process cartridges 2Bk and 2C are not shown.

  101a is a CRG holding right side plate for holding each process cartridge 2Y, 2M, 2C, 2Bk, and 101b is a CRG holding left side plate for holding each process cartridge 2Y, 2M, 2C, 2Bk. In this embodiment, the holding member is separated and the CRG holding right side plate 101a and the CRG holding left side plate 101b are provided in order to realize low cost. However, the holding members may be integrated or connected by separate members. It doesn't matter.

  This time, the holding member is the CRG holding right side plate 101a and the CRG holding left side plate 101b which are separate bodies. It is a holding member.

  Both the CRG holding right side plate 101a and the CRG holding left side plate 101b are provided with guide ribs 101a-a and 101b-a for supporting the lower side of the process cartridge when inserting the process cartridge and for smooth insertion. Further, pivot portions 101a-b and 101b-b are provided as rotation centers when the process cartridges are integrated together. In addition, openings 101a-c and 101b-c for escaping the driving side coupling portions and the non-driving side positioning bearing portions of the process cartridges 2Y, 2M, 2C, and 2Bk are provided. In addition, two bosses that are connecting portions to a link mechanism described later are provided.

  Next, the connection of the CRG holding plate 101 with the link mechanism and the actual movement will be described.

  3, 4, and 5 are schematic perspective views of the inside of the apparatus showing details of a link mechanism that is connected to the CRG holding right side plate 101 a and the CRG holding left side plate 101 b. FIG. 3 shows the state of the link mechanism at the position at the time of image formation, and FIG. 4 shows the state of the link mechanism when the open / close cover 14 is fully opened.

  FIG. 5 is an enlarged detailed perspective view of the link mechanism portion in the state of FIG.

  A state in which the opening / closing cover 14 is closed will be described with reference to FIGS. 3 and 5. The CRG holding plate 101 is pushed in by the link member group connected to the opening / closing cover 14, the door connecting plate 105, the intermediate rod 104, the rotating rod 103, and the CRG holding plate connecting rod 102, and is held by the holding spring 109. Yes. At that time, each process cartridge 2 is urged by a spring (not shown) so that the bearings of the process cartridge 2 are pressed against the two rear end faces and the lower end face of the printer main body of the positioning hole 106a provided in the central plate 106 on the main body. ing. The positioning of the process cartridge is performed on the main body side separately from the CRG holding plate 101 in this way, so that the CRG holding plate 101 has only a function as a rough guide for the process cartridge 2. Even when the process cartridge 2 is mounted, the operator may perform rough operations. Therefore, it is not necessary for the operator to mount the process cartridge 2 while confirming whether or not the process cartridge 2 is properly mounted, and the operability is improved.

  Finally, a state where the opening / closing cover 14 is completely opened will be described with reference to FIG. The link member group connected to the opening / closing cover 14, the door connecting plate 105, the intermediate rod 104, the rotating rod 103, and the CRG holding plate connecting rod 102 bring the CRG holding plate 101 into the position at the time of image formation as shown in FIG. Compared to the position having an angle of about 45 degrees. By moving the process cartridge 2 to such a position, access to the process cartridge 2 is improved, and attachment and removal are facilitated.

  Next, the process cartridge 2 of the present invention will be described in detail with reference to FIGS.

  FIG. 6 is a schematic sectional view of the process cartridge 2, and FIGS. 7 and 8 are schematic perspective views. The yellow, magenta, cyan, and black cartridges have the same configuration.

  The process cartridge 2 includes a photosensitive drum unit 2a that is a first frame including a photosensitive drum 21, a charging roller 23, and a cleaning unit, and a second developing unit that develops an electrostatic latent image on the photosensitive drum 21. Development unit 2b which is a frame body.

  In the photosensitive drum unit 2a, the photosensitive drum 21 is rotatably attached to the cleaning frame via a bearing. On the periphery of the photosensitive drum 21, a charging roller 22 that is a primary charging roller for uniformly charging the surface of the photosensitive drum 21 and a developer (toner) remaining on the photosensitive drum 21 are removed. The residual toner removed from the surface of the photosensitive drum 21 by the cleaning blade 28 is sequentially fed to a waste toner chamber 30 provided behind the cleaning frame 24 by the toner feeding mechanism 29. Then, the driving force of a driving motor (not shown) is transmitted to one end at the rear of the drawing, so that the photosensitive drum 21 is driven to rotate counterclockwise in the drawing according to the image forming operation.

  The developing unit 2b includes a developing roller 22 that is a developer carrying member that rotates in the direction of arrow Y in contact with the photosensitive drum 21, a toner container 70 that contains toner that is a developer containing portion, and a developing portion that is a developing portion. And a container 71. The developing roller 22 is rotatably supported by a developing container 71 via a bearing member, and a toner supply roller 72 and a developing blade 73 that rotate in the direction of arrow Z in contact with the developing roller 22 on the periphery of the developing roller 22. Are arranged respectively. Further, in the toner container 70, a toner stirring mechanism 74 for stirring the contained toner and transporting it to the toner supply roller 72 is provided. The toner container 70 and the developing container 71 are closed with a toner seal as a seal member so that the toner does not leak before use, such as at the time of shipment. By opening the toner seal at the start of use, the toner container 70 and the developing container 72 communicate with each other, and the toner in the toner container moves to the developing container.

  The developing unit 2b is configured such that the entire developing unit 2b is swingable with respect to the photosensitive drum unit 2a by pins 77a around support holes 77 provided in bearing members 75 and 76 attached to both ends of the developing unit 2b. When the image is formed, that is, at the time of image formation, the supporting roller 77 is used as a biasing member so that the developing roller 22 comes into contact with the photosensitive drum 21 by a rotational moment. The developing unit 2b is always urged by the springs 124a and 124b. At the time of non-image formation in which image formation is not performed, such as when transported or left for a long period of time, as shown in FIG. 13, a separation member 123 as a development separation member is attached to resist the pressure springs 124a and 124b. The separation member top surface grips the photosensitive drum unit top surface 3a, the separation member bottom surface 123c grips the development unit bottom surface 3b, and the developing roller 22 and the photosensitive drum 21 are brought into a non-contact state. Prevents deformation of the rollers. By removing the separating member 123, the separated state between the developing roller 22 and the photosensitive drum 21 can be released and brought into a contact state. When the developing roller 22 and the photosensitive drum are separated from each other, the rotation and positioning accuracy are better when the respective frames are supported and the respective frames are brought into contact with each other. Can be configured.

At the time of development, when the toner accommodated by the toner stirring mechanism 74 is conveyed to the toner supply roller 72, the toner supply roller 72 that rotates in the arrow Y direction slides with the developing roller 22 that rotates the toner in the arrow Z direction. The toner is supplied to the developing roller 22 by rubbing and is carried on the developing roller 22. The toner carried on the developing roller 22 reaches the developing blade 73 as the developing roller 22 rotates, and the developing blade 73 regulates the toner to give a desired charge amount, and a predetermined toner thin layer. To form. The regulated toner is transported to a developing position where the photosensitive drum 21 and the developing roller 22 are in contact with each other as the developing roller 22 rotates, and is subjected to photosensitivity by a DC developing bias applied to the developing roller 22 from a power source (not shown) at the developing position . The toner remaining on the surface of the body drum 21 is peeled off and collected from the developing roller 22. The collected toner is stirred and mixed with the remaining toner by the toner stirring mechanism 74.

  In the contact development method in which the development is performed with the photosensitive drum 21 and the developing roller 22 in contact as in the present invention, the photosensitive drum 21 is preferably a rigid body, and the developing roller 22 is preferably a roller having an elastic body. As this elastic body, a solid rubber single layer or a solid rubber layer coated with a resin coating in consideration of charge imparting property to toner is used.

  Next, the configuration according to the present invention will be described in detail with reference to FIGS.

(Charging roller)
The charging roller 23 and the supporting structure of the charging roller will be described with reference to FIG. The charging roller is configured by forming a conductive rubber member 23 a around a core bar 23 b and is pressed against the photosensitive drum 21 by a pressure spring (biasing member) 132 via a bearing 131 . The charging roller 23 is rotatably supported by the charging roller bearing 131, and the charging roller bearing 131 is supported by the guide portion 133. Here, the charging roller bearing 131 and the guide portion 133 are slidable, and the charging roller 23 is rotatable, and in the direction of the arrow in FIG. It is possible to move to.

(Charging moving member)
With reference to FIGS. 10 and 11, the separation member 123, which is a charging moving member , the supporting member 121, the charging moving portion 123 d, and the action portion 123 d-1 acting on the supporting member 121 in a part of the charging moving portion will be described. The support member 121 is formed of a bearing portion 121a, a connecting portion 121b, and an action hole portion 121c, and the charging roller core metal 23a is slidable on the bearing portion 121a. 121a is designed not to come into contact with the photosensitive drum 21, so that the surface of the photosensitive drum 21 is not damaged. The charging moving portion 123d moves the charging roller 23 in the contact and separation direction with respect to the photosensitive drum 21 through the support member by inserting the action portion 123d-1 into the action hole portion 121c of the support member 121. The insertion position is restricted by providing an insertion hole (not shown) in the photosensitive drum frame 24.

(Charging roller separation)
Since the charging roller is not strict in positioning accuracy and the like unlike the developing roller, the charging roller is not required to have a complicated configuration if the separation mechanism is provided with the same frame. A configuration for moving the charging roller will be described with reference to FIGS. 11 and 12. When the charging roller 23 is attached to the process cartridge with the charging roller 23 in contact with the photosensitive drum 21, the charging moving portion 123-d is inserted from an insertion hole (not shown) provided in the cartridge frame. When the action part 123d-1 enters the action hole part 121c and is further inserted, the action hole part 121c moves because the tip of the action part 123d-1 is inclined. By transmitting the movement of the action hole 121c to the bearing 121a via the connecting part 121b, the charging roller 23 is moved in a direction away from the photosensitive drum. The movement direction of the support member 121 is preferably substantially the same as the direction of the guide portion 133 of the charging roller bearing 131 and the overhead line connecting the center of the photosensitive drum and the center of the charging roller. On the opposite side in the longitudinal direction (not shown), the charging roller 23 is separated with the same configuration, and the pressure applied to the charging roller is released. Since the mechanism acts on the charging roller via the support member that supports the charging roller instead of directly acting on the charging roller 23 in this way, it is inserted into the frame around the charging roller that requires accuracy and rigidity. There is no need for special designs such as drilling holes. In addition, the charging and moving member can be adjusted by simply inserting and removing the charging roller by making the charging roller member a bar-shaped member with a tip at the tip and the support member as a hole. There is no need to provide it. In addition, since the contact and separation can be manually repeated even after the charging roller is released from the separated state, when the charging roller is released and the process cartridge is used, image formation is not performed for a long time. Can separate the charging roller again by applying a separation member to the process cartridge. In addition, since the charging moving member is moved substantially perpendicularly to the contact / separation direction of the charging roller 23 to make the charging roller 23 contact / separate, the charging moving member can be extended in the short direction. It becomes a simple structure without providing a new mechanism. In this embodiment, the charging roller 123 and the photosensitive drum 21 are completely separated from each other by the charging moving unit 123d. However, in order to release the pressure between the charging roller and the photosensitive drum, the charging roller 21 is slightly moved in the separation direction. It is good also as a structure which only moves. That is, during non-image formation when image formation is not performed, the separation member 123 is attached to the process cartridge 2 so that the pressure between the charging roller and the photosensitive drum is released, and when image formation is performed, that is, development is performed. If the configuration is such that the relative position in the contact / separation direction is determined by the charging moving member so that the separation member 123 is removed from the process cartridge and moved to a contact state where the charging roller can perform its function, the charging roller can be used. It does not matter whether the photosensitive drum is completely separated from the photosensitive drum.

In this embodiment the spacer member 123 is adapted to alternate the development separation member and the charging moving member. That is, the separation member 123 includes development separation action portions 123b and 123c, which separate the development roller 22 and the photosensitive drum 21. In addition, the charging roller 123d can be moved by the charging moving unit 123d. Therefore, when the separation member 123 is removed and the separation state of the developing roller is released, the charging roller can be brought into contact with the contact state capable of forming an image at the same time. Thus, when the user releases the separated state of the charging roller 23 and the separated state of the developing roller, the object can be achieved by a single operation of removing the separating member 123.

(Separation member and toner seal are connected)
The configuration of the present embodiment is almost the same as that of the first embodiment. However, as shown in FIG. 12, the end of the toner seal 82 is further affixed to the toner seal affixing surface 123a of the spacing member 123 as shown in FIG. ing. With such a configuration, when the user opens the toner seal, the separated state of the charging roller 23 and the separated state of the developing roller are released, so that there is no possibility of forgetting to remove the charging moving member. Also, the configuration for realizing this can be made very simple.

(Toner seal has extra length)
As in the second embodiment, the configuration of the present embodiment is such that a toner seal is connected to a spacing member. FIG. 14 shows a state in which the separation member 123 is attached to the cartridge frame 2, and FIG. 15 shows a state in which the separation member 123 is pulled out from the cartridge frame 2 to a predetermined position and the developing roller and the charging roller are in contact with the photosensitive drum. . The toner seal 125 has an extra length portion (flexible portion) 125 a in a state where the separation member 123 is attached to the cartridge frame 2. The length of the extra length portion 125a is set so that the extra length portion disappears after the separation member 123 is pulled out of the cartridge frame 2 and the development separation and the charging separation are released. That is, when the separation member is removed, if the separation member 123 moves to a predetermined position, the development separation / charging separation is released, and at that time, the toner seal is not opened, and then the separation member is further moved from the predetermined position. In this way, a two-step process is performed in which the toner seal is unsealed. Thereby, it mean that pulling force F ₂ required during the pulling-out force F ₁ and the toner seal pulling required when clearing away is configured not to act simultaneously.

In the present embodiment, the separation member 123 is described as a structure that serves as both a charging movement member and a development separation member. However, only the charging movement member (a structure that does not have a separation structure for the developing roller) or only the development separation member. even in the (mobile structure without the structure of the charging roller) to the toner seal was attached with extra length to the configuration, pulling force F ₂ required during the pulling-out force F ₁ and the toner seal pulling required spacing released simultaneously If it doesn't work, it will give a good effect. Accordingly, the separation member and the toner seal can be pulled out with a relatively light force.

  In the above-described embodiment, the separation member 123 can be removed from the process cartridge, but it is not always necessary to remove it. When the separation member is configured as a part of the process cartridge, after the separation member is moved and development separation, charging separation, etc. are released, the development separation member remains connected to the process cartridge, so the user removed the development separation member Later, the process of discarding it becomes unnecessary.

  In addition, this invention is not limited to the said Example. Forms other than the embodiments and arrangement of the constituent elements are possible, but the scope of the present invention is limited.

1 is a schematic cross-sectional view of a state during operation of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic perspective view showing the periphery of a process cartridge according to an embodiment of the present invention. 1 is a schematic perspective view showing the inside of an operating state of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic perspective view showing the inside of the image forming apparatus according to an embodiment of the present invention when the front door is opened. 1 is an enlarged schematic perspective view of a part of an internal state of an image forming apparatus according to an embodiment of the present invention during operation. 1 is a schematic sectional view of a process cartridge according to an embodiment of the present invention. 1 is a schematic perspective view of a process cartridge according to an embodiment of the present invention. 1 is a schematic perspective view of a process cartridge according to an embodiment of the present invention. 1 is a schematic side view of a charging roller according to an embodiment of the present invention. 1 is a schematic perspective view of a charging roller and a support member according to an embodiment of the present invention. 1 is a schematic perspective view of a charging roller, a supporting member, and a charging moving member according to an embodiment of the present invention. 1 is a schematic perspective view of a separation member according to an embodiment of the present invention. 1 is a schematic perspective view of a process cartridge when a separation member is mounted according to an embodiment of the present invention. The schematic top view of the process cartridge at the time of mounting of the separation member based on the Example of this invention The schematic top view of the process cartridge at the time of extraction of the spacing member concerning the example of the present invention

Explanation of symbols

2 process cartridge 2a photosensitive drum unit 2b developing unit 3a photosensitive drum unit top surface 3b developing unit bottom surface 11 polygon mirror 12 scanner motor 14 opening / closing cover 21 photosensitive drum 22 developing roller 23 charging roller 23a charging roller rubber portion 23b charging roller core metal 24 photosensitive Body drum frame 25 developing device 27 bearing 28 cleaning blade 29 toner feeding mechanism 30 waste toner chamber 35 intermediate transfer member (intermediate transfer belt)
50 Fixing portion 53, 54, 55 Discharging roller 56 Discharging tray 70 Toner container 71 Developing container 71a Opening portion 72 Toner supply roller 73 Developing blade 74 Toner stirring mechanism 75, 76 Bearing member 77 Support hole 77a Pin 101 CRG retaining plate 101a CRG retaining Right side plate 101a-a, 101b-a Guide rib 101a-c, 101b-c Opening 102 CRG holding plate connecting rod 101b CRG holding left side plate 103 Rotating rod 104 Intermediate rod 105 Door connecting plate 121 Support member 121a Bearing portion 121b Connecting portion 121c Action hole portion 123 Separating member 123a Toner seal sticking surface 123b Separating member top surface 123c Separating member bottom surface

Claims (7)

An image carrier;
Charging means for charging the image carrier in contact with the image carrier;
A first frame for holding the image carrier rotatably and holding the charging means movably in a contact and separation direction with respect to the image carrier;
A developer carrying member carrying a developer for developing an electrostatic latent image formed on the surface of the image carrying member;
A second frame which is movable with respect to the first frame and provided with the developer carrier; and the first frame for bringing the developer carrier and the image carrier into contact with each other. And a process cartridge that is attachable to and detachable from the image forming apparatus main body, and a biasing member that biases the second frame.
When the developing separation member is mounted on the process cartridge, the developing separation member moves the first frame and the second frame against the urging force of the urging member to move the developer. The charging unit and the image carrier when the carrier and the image carrier are separated from each other and the charging unit and the image carrier are separated from each other or when the developing separation member is mounted on the process cartridge. And keep it weaker than the contact pressure with
A process cartridge according to claim 1, wherein when the developing separation member is removed from the process cartridge, the developer carrier and the image carrier are in contact with each other, and the charging member and the image carrier are in contact with each other.   The process cartridge according to claim 1, wherein the development separation member and the image carrier are not in contact with each other when the development separation member is attached to the process cartridge.   The process cartridge according to claim 1, wherein the developing separation member can be manually attached to or detached from the process cartridge.   The developing separation member can be attached to or removed from the process cartridge by moving substantially perpendicular to the contact and separation direction in which the charging unit is movable. The process cartridge according to any one of claims 1 to 3.   The process cartridge according to claim 1, wherein the charging unit is supported by a support member that supports the charging unit without contacting the image carrier.   The support member has a hole, the developing separation member has a rod-shaped portion having an inclined tip, and the charging means is moved by inserting the rod-shaped portion into the hole. Item 6. The process cartridge according to Item 5. The second frame body develops the image carrier with a developer container for containing a developer for developing the electrostatic latent image formed on the surface of the image carrier, and the developer. A developing portion, and an opening communicating the developer containing portion and the developing portion,
A seal member that closes the opening is connected to the development spacing member;
The seal member closes the opening when the developer carrying member and the image carrying member are brought into contact with each other by moving the developing separation member from a state where it is attached to the process cartridge to a predetermined position. Remain
7. The process cartridge according to claim 1, wherein the seal member is opened by further moving the developing separation member from a predetermined position.

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