JP2007304173A - Process cartridge and electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge and an electrode member capable of effectively suppressing the occurrence of a charge memory even in case of mounting the process cartridge on an image forming apparatus body and transporting both in the same packing, and to provide an image forming apparatus having them. <P>SOLUTION: An electrostatic charge electrode plate 121 and a development electrode plate 131 of the process cartridge 1 are moved from a first position which is a position to short a photoreceptor drum and a conductive member to a second position which is a position usable by opening the short-circuit. When the process cartridge 1 is discretely packed or the process cartridge 1 and the image forming apparatus body are simultaneously packed and transported, the electrostatic charge electrode plate 121 and the development electrode plate 131 are held in the first position and thereby the occurrence of the electrostatic charge memory due to shortcircuiting is obviated even if the surrounding members are frictionally charged by the vibration, impact, etc., during transportation and even if the conductive member approximate to the photoreceptor drum 11 is discharged. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus (hereinafter referred to as “image forming apparatus”) such as an electrophotographic copying machine, a facsimile machine, an electrophotographic printer, and a multifunction machine, and relates to a replaceable process cartridge attached to and detached from the image forming apparatus. Is.

  In an image forming apparatus using electrophotographic technology, an electrostatic latent image carrier such as an electrophotographic photosensitive drum (hereinafter simply referred to as “photosensitive drum”) is uniformly charged with a charger, and exposure means such as a laser scanner is used. To form an electrostatic latent image. After the electrostatic latent image is developed on the photosensitive drum with a developer (toner) by a developing device, the toner image copied on a transfer material such as a sheet as a recording medium is heated and transferred by a transfer device. Press to fix.

  In order to simplify the maintenance and replacement work of consumables such as the photosensitive drum and toner generated by image formation, the photosensitive drum as an image forming element and process means such as charging and developing acting on the photosensitive drum are arranged around the drum. Are integrated into a cartridge. A process cartridge that can be easily attached to and detached from the image forming apparatus has been put into practical use. In addition to charging and developing process means, the process cartridge includes a case in which at least one of a transfer device and a cleaning device is combined with a photosensitive drum, and is attached to and detached from the image forming apparatus. Such a process cartridge is widely used today because the user can easily perform maintenance replacement work without losing time until the maintenance worker arrives.

  In recent years, there is a tendency to transport such a cartridge mounted on the main body of the image forming apparatus in order to reduce physical distribution costs (hereinafter referred to as bundled transport). However, carrying and transporting in such a manner causes a charging memory in which the photosensitive drum is charged due to friction with the packing material due to vibration during transportation and the like, which has an effect of reducing the image quality of the formed image. It is known that a charged memory is generated not only by the influence of vibration friction but also by static electricity on the user when the user attaches / detaches the process cartridge to / from the image forming apparatus main body.

  The charged memory has the following phenomenon. If a positive charge is charged on the surface of the photosensitive drum and stops, the negative charge induced from the conductive support is captured by a deep trap and cannot move from the interface. Therefore, even if charging and exposure are repeated, the negative charge remains at the interface between the charge generation layer and the charge transport layer for a while.

  With the goal of preventing charged memory, the present applicant has previously proposed a process cartridge and an image forming apparatus having a charged memory preventing function (see, for example, Patent Document 1). In this case, the conductive member is brought close to the photosensitive drum in contact or non-contact, and the photosensitive drum and the conductive member are electrically short-circuited, and the electrically shorted state is short-circuited by the short-circuit means. It is opened electrically.

Japanese Patent Laid-Open No. 9-6221

  However, the process cartridge disclosed in Patent Document 1 leaves room for improvement in the following points.

  In order to prevent the generation of the charged memory, it is desirable that the process cartridge is transported separately packed and transported in a state where the process cartridge is mounted on the main body of the image forming apparatus. However, in recent years, there has been a situation in which the image forming apparatus main body and the process cartridge have to be transported in a bundle as demands for reducing environmental burdens and transport costs have increased. If the problem of the charged memory can be overcome, there are many advantages such as reduction of the load space during transportation by bundled transportation. Therefore, it is strongly desired to satisfy both of the problems of preventing the generation of the charged memory and carrying the package.

  As described above, an object of the present invention is to provide a process cartridge and an image forming apparatus that can effectively suppress the generation of a charging memory even when the process cartridge is attached to the image forming apparatus main body and shipped together.

In order to achieve the above object, a process cartridge of the present invention comprises an electrophotographic photosensitive member carrying an electrostatic latent image,
A conductive member disposed in the vicinity of the electrophotographic photoreceptor;
Moving between a first position where the electrophotographic photosensitive member and the conductive member are electrically short-circuited and a second position where the electrophotographic photosensitive member and the conductive member are electrically opened. Possible electrode members.

  The image forming apparatus according to the present invention includes an electrophotographic photosensitive member carrying an electrostatic latent image, a conductive member disposed in the vicinity of the electrophotographic photosensitive member, the electrophotographic photosensitive member, and the conductive member. A process cartridge having a first position in an electrically shorted state and an electrode member movable between a second position in a state in which the electrophotographic photosensitive member and the conductive member are electrically opened; Mounting means for detachably mounting the process cartridge, wherein the process cartridge is transported with the electrode member positioned at the first position.

  According to the process cartridge of the present invention, a charging memory is not generated on the electrophotographic photosensitive member by short-circuiting the electrophotographic photosensitive member and the conductive member disposed in the vicinity thereof.

  Further, according to the image forming apparatus of the present invention, the influence of the charging memory on the image can be prevented by providing the process cartridge for suppressing the generation of the charging memory.

  Hereinafter, preferred embodiments of a process cartridge, an electrode member, and an image forming apparatus including the same according to the present invention will be described in detail with reference to the drawings.

(Image forming device)
FIG. 1 shows an apparatus main body A of a laser beam printer as a specific embodiment of the image forming apparatus. In the image forming section, a process cartridge 1 containing a photosensitive drum (electrophotographic photosensitive member) 1 as an image carrier is detachable. An exposure means (laser beam optical scanning system) 2 is disposed above the process cartridge. A feeding unit that feeds a sheet-like transfer material (hereinafter simply referred to as “sheet”) 31 serving as a recording medium is disposed below the process cartridge, and the toner image formed on the photosensitive drum 11 is transferred to the sheet 31. A transfer roller 33 for transferring is disposed. Further, fixing means 34 for fixing the toner image transferred to the sheet 31 and discharging means 35 for discharging and stacking the sheet 31 outside the apparatus are arranged. Examples of the sheet 31 include plain paper, an OHP sheet, and cloth.

(Feeding department)
The feeding unit is a device that feeds the sheets 31 to the image forming unit, and includes a feeding cassette 32a that stacks and stores a plurality of sheets 31, and includes a feeding roller 32b for feeding and a retard for preventing double feeding. A roller 32c, a feeding guide 32d, a registration roller 32f, and the like are included. The feeding roller 32b is driven and rotated in accordance with the image forming operation, and separates and feeds the sheets 31 in the feeding cassette 32a one by one. The retard roller 32c prevents so-called double feeding in which several sheets 31 are fed out simultaneously. The sheet 31 is guided by a feeding guide 32d and is conveyed to a registration roller 32f via a conveyance roller 32e. During the image forming operation, the registration roller 32f performs a non-rotating operation for allowing the sheet 31 to stand still and a rotating operation for conveying the sheet 31 toward the photosensitive drum 11 in a predetermined operation order, and performs the next transfer process. And aligning the toner image with the sheet 31. Immediately after the sheet 31 is conveyed, the registration roller 32f is in a stopped state, and the skew of the conveyed sheet 31 is corrected by entering the nip portion of the registration roller 32f.

(Process cartridge)
Next, the configuration of the process cartridge 1 will be described.

  A photosensitive drum 11 that is an electrostatic latent image carrier, and a charging device, a developing device, or a cleaning device as process means acting on the photosensitive drum 11 are integrated into a cartridge and integrated into a cartridge. The image forming apparatus main body includes one that can be attached and detached. In addition, there is also included one in which at least one of a charging device, a developing device, a transfer device, and a cleaning device and the photosensitive drum 11 are integrally formed into a cartridge so that the image forming apparatus main body can be attached and detached. In that case, as shown in FIG. 1, the charging device, the developing device, and the cleaning device can be arranged around the photosensitive drum 11 to be integrated. The process cartridge 1 configured as described above is detachable from the apparatus main body A. The user can easily perform maintenance work such as toner supply by opening or closing the cartridge cover 400 in FIG. 1 to easily attach or remove the process cartridge 1. When the recognition means determines that the cartridge has reached the end of its life, the end-of-life cartridge can easily be replaced based on the notification.

  In the process cartridge 1 of the present embodiment, the photosensitive drum 11 receives the rotational power from the rotational drive source of the apparatus main body A and rotates in the clockwise direction indicated by the arrow r in FIG. A predetermined charging bias voltage is applied to the charging roller 12 of the charging device which acts as a process means on the photosensitive drum 11, and the drum surface of the photosensitive drum 11 is uniformly charged by the charging roller 12. The charged photosensitive drum 11 is exposed to a light image based on image information from the exposure device 2 to form an electrostatic latent image, and the electrostatic latent image is developed by the developing device 13.

  The developing device 13 includes a developing roller 131 that carries the developer (toner) accommodated in the developer accommodating chamber 130. The developing roller 131 is provided with a developing blade 132 that forms a toner layer imparted with triboelectric charge on the surface of the developing roller 131 by rotating the developing roller 131. As a result, a predetermined developing bias voltage is applied to the developing roller 131 by the bias voltage applying means provided in the apparatus main body A, and the toner is transferred to the photosensitive drum 11 in accordance with the electrostatic latent image to form a toner image. Visualize.

  Further, the cleaning device 14 has a cleaning blade 141, and applies a voltage having a reverse polarity to the toner image to the transfer roller 33, and scrapes off residual toner remaining on the photosensitive drum 11 after the toner is transferred to the sheet 31. Further, the cleaning blade 141 is scooped by the sheet member 142 and stored in the waste toner storage chamber 143. The residual toner remaining on the photosensitive drum 11 is removed by operating the cleaning device 14 in this way.

  That is, the process cartridge 1 of the present embodiment includes a charging roller 12, a developing roller 131, a cleaning blade 141, and the like as process means that act on the photosensitive drum 11. Among them, members that function as a bias application type process means are the charging roller 12 and the developing roller 131.

  Next, the fixing device 34 transfers the toner image on the photosensitive drum 11 onto the sheet 31 by the transfer roller 33, and heats and pressurizes the transferred toner image to fix it on the sheet 31. Therefore, a fixing roller 34a for applying heat to the sheet 31 is provided, and a pressure roller 34b for pressing the sheet 31 against the fixing roller is provided. The fixing roller 34a and the pressure roller 34b are formed in a hollow shape, and a heater (not shown) is mounted inside the hollow portion. Each roller is driven to rotate to convey the sheet 31. The sheet 31 holding the toner image is conveyed by the fixing roller 34a and the pressure roller 34b, and the toner image is fixed to the sheet 31 by heating or pressing. The sheet 31 after fixing is discharged by the discharge roller 35.

(Aspect by bundled transportation)
Next, “bundled transport” when transporting the process cartridge 1 together with the process cartridge 1 mounted on the apparatus main body A will be described.

  The sales form in which the process cartridge is attached to the image forming apparatus main body A as one set has the advantage of freeing the user from the complexity of individual purchase. In addition, if bundled transportation is possible, the packaging can be reduced in size and the transportation space can be greatly reduced compared to the case of individual packaging, which greatly reduces packing materials and transportation costs. It is effective for. In addition, since the process cartridge is already set in the main body of the image forming apparatus when unpacking after purchase, the user can save the trouble of reading and installing the instruction manual. If the image forming apparatus main body is activated by connecting a power outlet or a communication cable as it is, so-called plug and play becomes possible.

(Suppression of occurrence of charged memory)
The charged memory that may be generated by the bundled transportation is suppressed as follows.

  2 to 4 show one side cross-section of a state in which it is assumed that a charging memory is generated when the photosensitive drum 11 of the present embodiment is an organic photosensitive drum and has a laminated drum structure. That is, in this case, the laminated photosensitive drum 11 is obtained by laminating a charge generation layer 11b and a charge transport layer 11c on a conductive base 11a such as aluminum.

  As shown in FIG. 3, a charging memory is intentionally generated at a predetermined portion of the photosensitive drum 11, and an analysis of the generation mechanism is attempted. After primary charging by the charging roller 12, as shown in FIG. 4A, when a predetermined portion of the drum is exposed, injection of positive charges from the charge generation layer 11b to the charge transport layer 11c is more likely to occur than usual. As a result, the apparent sensitivity is increased, and the charge on the surface of the photosensitive member is lost at the predetermined portion as compared with other drum portions. FIG. 4B is a graph showing the surface potential of the photosensitive drum 11 under such a state. As is apparent from this graph, the positive charge is easily injected at the site where the charging memory is generated, so that the charge on the surface of the photosensitive member is lost compared to the other sites and the potential at the time of exposure is obtained. Some bright part potentials are lower than other parts. In reversal development, a larger amount of toner adheres to the part where the potential is lower than usual, so it is noticeable blacker than the surroundings. In regular development, the developer is less likely to adhere to the part where the potential is lower, so halftone images Becomes a whitish and abnormal image.

  The following phenomenon is considered as the charge that causes the charging memory. One is due to charging of the packing bag and the process cartridge frame. The insulating packing bag and the cartridge frame are charged by friction during transportation and the like, and the charge is discharged from the conductive member around the drum to the photosensitive drum 11. One is due to static electricity on the user's body. When a user's finger charged with static electricity touches the electrode of the conductive member, the electric charge is discharged from the conductive member to the photosensitive drum 11. One is due to the influence of the external electric field. That is, when the process cartridge frame is placed on the charged insulating resin, the charge is discharged from the conductive member to the photosensitive drum 11. As described above, the charge is transferred to the conductive member adjacent to the photosensitive drum 11, thereby generating a potential difference between the photosensitive drum 1 and the conductive member, and positive charge is discharged from the conductive member to the photosensitive drum 11. This causes the charging memory to be generated.

  That is, it can be seen that if an object or substance charged by friction or the like is present around the process cartridge 1, it is discharged to a conductive member in the vicinity of the photosensitive drum 11 to easily generate a charged memory. The main body of the image forming apparatus and the process cartridge 1 are composed of a large number of devices and members. Therefore, it becomes easy to be charged by friction caused by vibration or impact during transportation. In particular, during transportation by bundling, the influence of each device or member on the apparatus main body A side disposed around the process cartridge 1 becomes more remarkable.

  From the above, in order to prevent the occurrence of charging memory, it is necessary to prevent a potential difference from occurring between the conductive member adjacent to the photosensitive drum 11. In order to eliminate the potential difference so that no discharge occurs, that is, to make the photosensitive drum 11 and the conductive member have the same potential, it is conceivable to electrically short-circuit. Hereinafter, the short-circuit structure will be described in order.

  First, the process cartridge 1 is mechanically positioned and electrically connected at a predetermined position of the apparatus main body A with high accuracy, thereby enabling high-quality image formation. For this purpose, the process cartridge 1 is provided with a “cartridge positioning mechanism”, a “photosensitive drum driving mechanism”, a “charging bias applying mechanism”, and a “developing bias applying mechanism” as mechanical and electrical interfaces. ing.

(Process cartridge side interface)
As shown in FIG. 5 showing the side surface of the cartridge, a cartridge frame is formed by the exterior cover 101, and a guide member 1011 for guiding an insertion operation when the cartridge frame is mounted to the apparatus main body A is provided on the side surface of the cartridge frame. ing. The guide member 1011 has an opening 1011a, and the passive coupling 111a is viewed through the opening 1011a. The passive coupling 111a functions as a connection portion with the cartridge positioning mechanism, and also functions as a connection portion between the photosensitive drum driving mechanism, the charging bias applying mechanism, and the developing bias applying mechanism, and an interface between these four mechanisms. Also serves as.

  The photosensitive drum driving mechanism receives rotational power from a motor of a rotational driving source provided in the apparatus main body A through the drum shaft 111, and the photosensitive drum 11 is rotationally driven. The photosensitive drum 11 is grounded via a passive coupling 111a. The charging bias application mechanism has a charging electrode plate 121, and a charging bias voltage from a power supply voltage installed in the apparatus main body A is applied to the charging roller 12 via the charging electrode plate 121 when the cartridge is mounted. . The development bias application mechanism has a development electrode plate 133, and a development bias voltage from a power supply voltage is applied to the development roller 131 via the development electrode plate 133. The charging electrode plate 121 is viewed from the opening 1012 to the outside of the cartridge frame, and the developing electrode plate 133 is viewed from the opening 1013 to the outside of the cartridge frame.

  The charging bias applying mechanism and the developing bias applying mechanism can be collectively referred to as a bias applying type process means, and representative devices in both mechanisms are the charging roller 12 and the developing roller 131.

(Device main unit side interface)
FIG. 6 shows a cartridge positioning mechanism provided on the apparatus main body A side when the apparatus main body A is viewed from the side when the process cartridge 1 is taken out. When the process cartridge 1 is attached to or detached from the apparatus main body A, the user opens and closes the cartridge cover 400. The side plate 40 forming the exterior frame of the apparatus main body A is provided with a guide rail 401 that guides when the cartridge is attached / detached. A guide member 1011 (FIG. 5) provided on the process cartridge 1 side is guided and inserted into the guide rail 401 so that the process cartridge 1 can be easily and accurately mounted at a predetermined position of the apparatus main body A.

  In addition, the drive coupling 41 is engaged with the passive coupling 111a on the process cartridge 1 side when the cartridge is inserted. When the passive coupling 111a is engaged with and connected to the drive coupling 41, the rotational power of the rotational drive source motor is transmitted from the drive coupling 41 to the passive coupling 111a to rotate the photosensitive drum 11. become. By connecting the drive / passive couplings 41 and 111a, the photosensitive drum 11 is energized through the drum shaft 111 and is grounded to the ground.

  Further, the charging contact 42 and the developing contact 43 are provided through the openings 402 and 403 provided in the frame side plate 40. By inserting the cartridge, the charging contact 42 and the developing contact 43 can be electrically connected to the charging roller 12 and the developing roller 131, respectively. That is, a charging bias applying mechanism and a developing bias applying mechanism for applying a bias voltage by inserting a cartridge are electrically connected to the charging contact 42 and the developing contact 43 via the charging electrode plate 121 and the developing electrode plate 133.

(Charging electrode plate, development electrode plate)
FIG. 7 shows the photosensitive drum 11, the charging roller 12 and the developing roller 131 (conductive member), the developing blade 132, the cleaning member 141, and the like constituting the process cartridge 1. The cleaning support metal plate 141a that supports the developing blade 132 and the cleaning member 141 is a conductive member made of metal or the like.

  Therefore, the charging electrode plate 121 is a metal material having elasticity such as a spring member, and is supported so as to be swingable by support means (not shown) with respect to the swing center 121a. The charging electrode plate 121 has first to fourth connection portions, and is electrically connected to each connection portion. The first connecting portion 121b1 is in electrical contact with the charging roller shaft 12a, the second connecting portion 121b2 is in contact with the conduction plate 112, the third connecting portion 121b3 is in contact with the charging contact 42, and the fourth connecting portion 121b4 is It contacts the cleaning support sheet metal 141a.

  The developing electrode plate 133 is a spring-like metal material like the charging electrode plate 121, and is supported by a support means (not shown) so as to be swingable with respect to the swing center 133a. The developing electrode plate 133 has first to fourth connection portions, and is electrically connected to each connection portion. The first connecting portion 133b1 is in electrical contact with the developing roller shaft 131a, the second connecting portion 133b2 is in contact with the conduction plate 112, the third connecting portion 133b3 is in contact with the developing contact 43, and the fourth connecting portion 133b4 is Contact the developing blade 132.

  In the state shown in FIG. 7, the charging roller 12, the cleaning support metal plate 141 a and the conducting plate 112 are electrically connected by the charging electrode plate 121, and the developing roller 131, the developing blade 132 and the conducting plate 112 are electrically connected by the developing electrode plate 133. When it is connected.

  FIG. 8 shows the engagement between the drum shaft 111 and the exterior cover 101 with respect to the conductive plate 112. The conductive plate 112 made of a metal material has a connection portion 112 a that is electrically connected to the drum shaft 111. In the state of FIG. 7, the photosensitive drum 11, the charging roller 12, the developing roller 131, the developing blade 132, and the cleaning member support metal plate 141 a are electrically short-circuited and have the same potential. In this manner, the conductive member adjacent to the photosensitive drum 11 is electrically short-circuited, and the position state where the charging electrode plate 121 and the developing electrode plate 133 are short-circuited as shown in FIG. " On the other hand, with respect to the first position, as shown in FIG. 9, the conductive member adjacent to the photosensitive drum 11 is electrically opened, and a predetermined bias voltage is applied to the charging bias applying mechanism and the developing bias applying mechanism. Hereinafter, a position state in which can be applied is referred to as a “second position”.

  That is, as shown in FIG. 9, the charging electrode plate 121 and the developing electrode plate 133 move from the first position to the second position. That is, in FIG. 7, the charging electrode plate 121 and the developing electrode plate 133 are in a state of swinging from the first position with reference to the swing centers 121a and 133a. As is apparent from FIG. 9, the first connecting portion 121b1 of the charging electrode plate 121 is in contact with the charging roller shaft 12a as in the first position, and the second connecting portion 121b2 is separated from the conductive plate 112. The fourth connecting portion 121b4 is also separated from the cleaning support sheet metal 14a. The third connecting portion 121b3 is in contact with the charging contact 42 of the apparatus main body A. Similarly, in the developing electrode plate 133, the first connecting portion 133b1 is in contact with the developing roller shaft 131a, and the second connecting portion 133b2 is separated from the conductive plate 112. The fourth connecting portion 133b4 is at a distance away from the developing blade 132, and the third connecting portion 133b3 is in contact with the developing contact 43 of the apparatus main body A.

  Therefore, the photosensitive drum 11, the charging roller 12, the developing roller 131, the developing blade 132, and the cleaning support metal plate 14a are in the second position in FIG. At the same time, the charging contact 42 and the developing contact 43 of the apparatus main body A are electrically connected to the charging electrode plate 121 and the developing electrode plate 133, respectively.

  As is clear from the above, the second position allows the conductive member adjacent to the photosensitive drum 11 to be electrically opened, and a predetermined bias voltage can be applied to the charging bias applying mechanism and the developing bias applying mechanism. State.

  Note that both the charging electrode plate 121 and the developing electrode plate 133 are elastically urged in a direction to be held in a state of being located at the first position by an urging means (not shown) such as a spring member.

(Drive / passive coupling connection structure)
Next, a connection structure between the drive coupling 41 on the apparatus main body A side and the passive coupling portion 111a provided at the tip of the process cartridge side drum shaft 111 will be described.

  In FIG. 10 showing the drive / passive couplings 41 and 111a before connection, the passive coupling 111a at the tip of the drum shaft 111 has a connection convex portion 111a1 having a triangular cross section for drive transmission and alignment functions. ing. The connecting projection 111a2 has a connecting projection 111a2 having a circular cross section for projecting further forward from the tip of the connecting projection 111a1 for positioning in the cartridge longitudinal direction. This connection convex part 111a2 also serves as a part for connecting the photosensitive drum 11 to the ground.

  On the other hand, the drive coupling 41 is configured by providing a transmission portion 41a of a portion connected to the passive coupling 111a at the tip of the rotating shaft 41b. A connection concave portion 41a1 having a triangular cross section is provided from the front end surface of the transmission portion 41a, and the photosensitive drum 11 is rotationally driven by engaging with the connection convex portion 111a1 on the passive coupling 111a side. At the same time, automatic alignment is performed by matching the rotational axes of both the drive and passive couplings by connecting the connection uneven portions 41a1 and 111a1. At the same time, by engaging the connection convex portion 111a2 and the connection concave portion 41a2, the photosensitive drum 11 is grounded to the ground, and the earth connection is performed.

  Although not shown in the drawings, the rotary shaft 41b having the transmission portion 41a at the tip is supported so as to be movable in the direction of the rotation axis, and is urged toward the drum shaft 111 by a compression spring or the like. Yes. The drive coupling 41 is a link member and is movable in the longitudinal direction in conjunction with the opening / closing operation of the cartridge cover 400.

  Next, FIGS. 11A to 11C show connection and disconnection operations of the drive coupling 41 and the passive coupling 111a.

  The photosensitive drum 11 has a shape in which a drum shaft 111 is inserted through an inner central axis of a cylindrical drum cylinder 110. As shown in FIG. 2 and the like, the drum cylinder 110 has a laminated structure in which a charge generation layer 11b and a charge transport layer 11c are sequentially laminated on a conductive support 11a such as aluminum. Connected. The drum cylinder 110 is coupled to the drum shaft 111 on the same axis by a drum flange 113, and includes a ground plate 114 for electrically connecting the drum cylinder 110 and the drum shaft 111.

  FIG. 11A shows a separated state before the drive coupling 41 and the passive coupling 111a are connected. From this state, the drive coupling 41 slides in the longitudinal direction in conjunction with the opening / closing operation of the cartridge cover 400. When the cartridge cover 400 is opened, the drive coupling 41 is in the standby position and is separated from the passive coupling 111a. This is because when the process cartridge 1 is attached to or detached from the apparatus main body A, the mounting direction is mounted in a direction perpendicular to the drum shaft 111 (see FIG. 6). That is, if the drive coupling 41 does not stand by at a position separated from the process cartridge 1, the mounting is hindered.

  Next, as shown in FIG. 11B, when the cartridge cover 400 is closed by the user, the drive coupling 41 moves toward the drum shaft 111 by the operation of a link member (not shown). At this time, when the triangular phase of both the connection concave portion 41a1 and the connection convex portion 111a1 having a triangular cross section are different, the end surface of the connection convex portion 111a1 and the inlet end surface of the connection concave portion 41a1 come into contact, and the transmission portion 41a stops here. It will be in the state. The overstroke in the amount of movement of the drive coupling 41 is absorbed by the slide means or the compression spring. In this state, the photosensitive drum 11 cannot be rotated or grounded.

  Further, when the triangular phases of both the connection concave portion 41a1 and the connection convex portion 111a1 are substantially the same, as shown in FIG. 11C, the connection convex portions 111a1 and 111a1 are engaged with the connection concave portions 41a and 41a2. The photosensitive drum 11 can be rotated and connected to the ground. This state is referred to as a usable state in the following description.

  When in the standby state, the rotational shaft 41b is driven to rotate so that the triangular phases of both the connection recess 41a1 and the connection protrusion 111a1 are matched. At this time, the transmission portion 41a is pushed out in the direction of the drum rotation axis by a compression spring or the like, and the connection concave portion 41a1 and the connection convex portion 111a1 are engaged to become usable.

  On the other hand, FIGS. 12A and 12B show the connection convex portion 111a1 and the connection concave portion 41a1 in the aligning operation for matching the axes at the time of coupling connection. The connection convex portion 111a1 has an equilateral triangle shape with the rotation axis C2 at the center of the drum shaft 111 as the centroid, and the connection recess portion 41a1 has an equilateral triangle shape with the rotation axis C1 at the center of the rotation shaft 41b as the centroid. The circumscribed circle R2 of the connecting convex portion 111a1 is set to be smaller than the circumscribed circle R3 of the connecting concave portion 41a1 and larger than the inscribed circle R1.

  As shown in FIG. 12A, by rotating the rotation shaft 41b, each side of the connection concave portion 41a1 engages with each vertex of the connection convex portion 111a1, thereby enabling drive transmission. At this time, each side of the connection concave portion 41a1 is limited to one place where each vertex of the connection convex portion 111a1 comes into contact, so that the rotation axis C2 of the photosensitive drum 11 and the rotation axis C1 of the rotation shaft 41b coincide with each other. It is aligned.

  Even when the rotation axis C1 of the rotation shaft 41b is deviated from the rotation axis C2 of the drum shaft 111 as shown in FIG. Is aligned. Therefore, when the process cartridge 1 is mounted on the apparatus main body A, a high-accuracy image can be obtained even if the mounting position of the process cartridge 1 is slightly rough.

(Operation of electrode plate)
Next, FIGS. 13A to 13C typically show the operation of the charging electrode plate 121 out of the charging electrode plate 121 and the developing electrode plate 133, and FIG. 13A shows the retraction of the drive coupling 41. FIG. 4B shows a standby state, and FIG. 3C shows a usable state.

  In this embodiment, the movement between the first position of the charging electrode plate 121 (and the developing electrode plate 133) and the second position in the applied state is interlocked with the movement of the drive coupling 41. Specifically, as the drive coupling 41 moves from the retracted state to the usable state, the charging electrode plate 121 comes into contact with the second connecting portion 121b2 and the end surface of the drive coupling 41 on the drum shaft 111 side. Move from the first position to the second position.

  That is, when the drive coupling 41 is in the retracted state, the charging electrode plate 121 is held in the first position by the urging means as shown in FIG. Therefore, the charging roller 12, the photosensitive drum 11 and the cleaning support metal plate 141a (via the conductive plate 112) are electrically short-circuited by the first connecting portion 121b1, the second connecting portion 121b2, and the fourth connecting portion of the charging electrode plate 121. It is in the state.

  In the standby state, the drive coupling 41 enters the drum opening 1011a as shown in FIG. 13B. In this state, the drive coupling 41 and the second connection portion 121b2 are separated from each other. Yes. That is, the charging electrode plate 121 remains held at the first position.

  Next, when in a usable state, as shown in FIG. 13C, the coupling 41 and the second connecting portion 121b2 come into contact with each other and are pushed in (upward in the drawing). Here, since the charging electrode member 121 is supported so as to be swingable with respect to the swing center 121a, the charge electrode member 121 swings with respect to the swing center 121a as shown in FIG. At this time, the second connecting portion is separated from the conducting plate 112, the fourth connecting portion 121b4 is separated from the cleaning support metal plate 141a, and the third connecting portion 121b3 is in contact with the charging contact 42 of the apparatus main body. That is, the charging electrode plate 121 moves from the first position to the second position during the period from the standby state to the usable state.

  When the process cartridge 1 is attached or detached, the drive coupling 41 is again retracted by opening the cartridge cover 400, and the charging electrode plate 121 is moved from the second position to the first position in accordance with this operation. It moves by the urging force of the urging means. That is, the charging electrode plate 121 is moved from the first position to the second position by the drive coupling 41. Therefore, when the process cartridge 1 is outside the apparatus main body A, it is held in the first position when the drive coupling 41 is in the retracted state or standby state even if it is attached to the apparatus main body A. When the process cartridge 1 is mounted on the apparatus main body A and the drive coupling 41 is in a usable state, the process cartridge 1 is held in the second position by the drive coupling 41.

  Thus, when the process cartridge 1 is outside the apparatus main body, the charging electrode plate 121 and the developing electrode plate 133 are each held in the state of the first position.

  Accordingly, as described above, the photosensitive drum 11 and the conductive member adjacent to the photosensitive drum 11 are electrically short-circuited. Therefore, in the single state of the process cartridge 1, it is possible to prevent charging memory due to (a) charging of the packing bag and the process cartridge frame, (b) static electricity of the user, and (c) influence of an external electric field. It becomes.

  When in the retracted state, as shown in FIG. 13A, the drive coupling 41, the charging electrode plate 121, and similarly the developing electrode plate 133 are in an unloaded state with respect to the mounting direction of the process cartridge. Therefore, when the process cartridge 1 is attached to and detached from the apparatus main body A, the process can be performed smoothly.

(Installation of process cartridge when installed)
The drive coupling 41 has three states: a retracted state (FIG. 11 (a)), a standby state (FIG. 11 (b)), and a usable state (FIG. 11 (c)). When carrying out attachment bundling and carrying the apparatus main body A, it is as follows.

  First, in order to bring the drive coupling 41 into the retracted state, the cartridge cover 400 must be opened. As a matter of course, since transporting in this state does not reduce the transportation cost, it is necessary to hold the drive coupling 41 in the retracted state even when the cartridge cover 400 is closed in order to realize mounting and packaging. is there. For this reason, the link means for moving the drive coupling 41 for the opening / closing operation of the cartridge cover 400 needs to perform an operation corresponding to a normal attaching / detaching operation and an operation corresponding to mounting and packaging, so that the link member is complicated. It will become something.

  In such a retracted state, as shown in FIG. 13A, the process cartridge 1 can be smoothly attached and detached. That is, in this state, if a vibration or impact is applied due to transportation during mounting and packaging, the process cartridge may be exposed in the apparatus main body and may be damaged.

  Next, in the usable state, as shown in FIG. 9 and FIG. 11C, the charging electrode plate 121 and the charging contact 42, the developing electrode plate 133 and the developing contact 43, which are electrical interfaces, are connected to the ground. The connecting projection 111a2 of the passive coupling 111a to be performed and the connecting recess 41a2 of the drive coupling 41 are in contact with each other.

  That is, the charging electrode plate 121, the developing electrode plate 133, and the connecting convex portion 111a2 are disposed on the process cartridge 1 side, and the charging contact 42, the developing contact 43, and the connecting concave portion 41a2 are disposed on the apparatus main body A side. Therefore, if vibration or impact during transportation is applied, there is a possibility that damage or deformation due to the influence of each vibration or impact, or shaving powder due to rubbing may occur.

  Further, as shown in FIG. 11C, the coupling portion 111 and the driving coupling 41 which are driving and positioning interfaces are also connected to the connecting convex portion 111a1 having a triangular cross section and engaged with the concave portion 41a1. And the front end surface of the connection convex part 111a2 and the bottom face of the connection recessed part 41a2 will be in the contact state. Therefore, like the electrical interface, there is a possibility of being affected by vibration and impact during transportation.

  Each vertex of the equilateral triangle of the connection convex portion 111a1 and each side of the equilateral triangle of the connection concave portion 41a1 are extremely important portions when aligning the photosensitive drum 11 and the drive coupling 41, and this portion is damaged. In some cases, there is a possibility that the respective centers will be shifted. As a result, there is a possibility that the photosensitive drum 11 will cause rotation unevenness. As for the usable state, since the charging electrode plate 121 and the developing electrode plate 133 are in the second position, there is a possibility that a charging memory is generated.

  Next, in the standby state, as shown in FIG. 11B, in the standby state, the phase of the equilateral triangle of the connection convex portion 111a1 having a triangular cross section and the phase of the equilateral triangle of the connection concave portion 41a1 are different. Therefore, the front end surface of the connection convex portion 111a1 is in contact with the inlet end surface of the connection concave portion in the connection portion 41a. In that case, each vertex in the equilateral triangle of the connection convex part 111a1 is not contacting any part. Moreover, the connection convex part 111a2 is accommodated in the inside of the connection concave part 41a1, and it is not in contact with any part also in the front end surface of the connection convex part 111a1 which is a longitudinal positioning and earthing connection part. Therefore, even if there is a vibration or impact during transportation, each vertex in the equilateral triangle of the connection convex portion 111a1 is not damaged. Further, the transmission portion 41a is housed in the drum opening portion 1011a, and a gap is formed between the outer shape of the transmission portion 41a and the drum opening portion 1011a as shown in FIG. This gap is set to be sufficiently smaller than the gap formed between the outer diameter of the connection convex portion 111a2 and the connection concave portion 41a2. Therefore, even if there is a vibration or impact at that time during transportation in this state, the connection convex portion 111a2 and the connection concave portion 41a2 do not contact each other.

  That is, in the standby state, the process cartridge 1 and the apparatus main body A are in contact with only the outer shape of the connecting portion 41a, the inner surface of the drum opening 1011a, and the front end surface of the convex triangular portion 111a1 and the inlet end surface of the concave triangular portion. is there. Since neither of these is a portion having a function as an interface between the process cartridge 1 and the apparatus main body A, even if it is slightly damaged by vibration or impact during transportation, there is almost no problem in terms of quality.

  Further, since the charging electrode plate 121 and the developing electrode plate 133 are in the first position in the standby state, no charging memory is generated, and at the same time they are separated from the charging contact 42 and the developing contact 43 of the apparatus main body A. is there. Therefore, problems such as damage and deformation of these parts and scraping powder due to rubbing do not occur. That is, if the process cartridge 1 is mounted on the apparatus main body so as to be in a standby state when packaged and transported, it can be transported without causing the problems raised so far.

  Next, how the process cartridge 1 is mounted on the apparatus main body A so as to be in a standby state will be described.

  Regarding the mounting and bundling performed by a production department such as a factory, when producing the apparatus main body A and the process cartridge 1, by deciding how the phases of the connection concave portion 41a and the connection convex portion 111a1 should be determined upon completion, It is always possible to wear it in a standby state. On the other hand, when the user performs mounting and packaging, it is difficult to rotate the drum shaft 11 and the drive coupling 41 of the process cartridge 1 alone as in the production department. Therefore, the apparatus main body A is used to realize mounting in the standby state. First, a drive sequence (hereinafter referred to as a mounting and bundling sequence) for mounting and bundling is prepared in the apparatus main body A. The mounting bundling sequence is a sequence executed based on the operation flowchart (step S1 to step S8) shown in FIG.

  The operation of each step of the mounting bundling sequence and the actual phase movement of the connecting convex portion 111a1 and the connecting concave portion 41a1 will be described with reference to FIGS. 11 (a) to 11 (c).

  First, in step S1, the user executes a mounting and bundling sequence. The mounting and bundling sequence is executed in a state where the process cartridge 1 is mounted on the apparatus main body. As an execution method, there is a method of providing a specific command on an operation panel (not shown) of the apparatus main body A or a device connected to the apparatus main body.

  Recognizing that the mounting and bundling sequence has been executed, the apparatus main body A rotationally drives the drive coupling (step: S2) and stops in the state when the phase is as shown in FIG. : S3). In this state, the user takes out the process cartridge 1 from the apparatus main body (step: S4). At this time, the connection convex portion 111a1 is in a state in which the vertex of the regular triangle faces upward. After the process cartridge is taken out, the drive coupling rotates again (step: S5), and this time, it stops in the state when the phase shown in FIG. 11B is reached (step: S6). At this time, the connection recess 41a1 is in a state where the apex of the regular triangle faces downward. Subsequently, the user mounts the process cartridge on the apparatus main body (step: S7), and the mounting and bundling sequence ends (step: S8).

  By executing the above mounting and bundling sequence, the phase of the connection convex portion 111a1 and the phase of the connection concave portion 41a1 are always different, so the connection convex portion 111a1 and the connection concave portion 41a1 are not engaged. Can be packaged.

(Image formation process)
When transported by mounting and packaging, the drive coupling 41 is in a standby state. Therefore, the drive coupling 41 is driven and rotated, and the charging bias voltage and the developing bias voltage are applied after the standby state becomes usable. In this embodiment, since the coupling used for the drive transmission interface is an equilateral triangle, the phase of the connection convex portion 111a1 and the connection concave portion 41a1 must be in agreement with each other if they are rotated by 120 degrees or more. Is ready to use. In other words, even in the standby state, after the drive coupling 41 has rotated 120 degrees or more, it can be used, and the application of the charging bias voltage and the developing bias voltage may be executed thereafter.

   As described above, when the electrode member is in the first position, the conductive member adjacent to the photosensitive drum 11 is brought into an electrically shorted state with the photosensitive drum 11. As a result, it is possible to prevent the occurrence of a charged memory due to (1) charging of the package and the process cartridge frame, (2) static electricity of the user, and (3) the influence of an external electric field. The electrode member moves the electrode member from the first position to the second position by the operation of mounting the process cartridge 1 on the apparatus main body A and engaging the drive coupling 41. As a result, the electrical short-circuit state becomes an open state and can be used.

  When the conductive member is a charging bias applying mechanism or a developing bias applying mechanism, the electrode member is connected to the bias applying mechanism of the apparatus main body A when the electrode member is in the second position by the connecting portion of the electrode member. A bias voltage can be applied. Here, when the electrode member is in the first position, the contact between the electrode member and the apparatus main body is separated, and therefore, the electrode plate and the contact of the apparatus main body are not damaged even when the electrode member is moved during mounting. In addition, since the drive coupling 41 is held at the standby position during transportation when mounted and bundled, the portion for aligning and positioning is not damaged.

  In addition, although the said embodiment was described about this invention, it is not limited to that embodiment, As long as it is in the range which does not deviate from the main point of this invention, other embodiment, an application example, a modification, and those combination Is also possible.

  For example, in the above embodiment, the structure in which the electrode member moves from the first position to the second position by engagement with the drive coupling has been described. However, a dedicated moving means for moving the electrode member is provided. Also good.

  In the above embodiment, the electrophotographic photosensitive member is a photosensitive drum, the charging unit is a charging roller, the developing unit is a developing roller, and the regulating member that regulates the developer on the developing roller is a developing blade and the cleaning unit. Uses a cleaning blade. However, as long as the configuration has the same function, the electrophotographic photosensitive member may be a photosensitive belt, the charging unit may be a corona charger, the cleaning unit may be a roller cleaner, or the like. As for developing means, a magnetic developing method using a magnetic developer, a non-magnetic developing method using a non-magnetic developer, a contact developing method in which a developing roller and a photosensitive drum are brought into contact with each other, and a predetermined distance between the developing roller and the photosensitive drum. A non-contact developing method having a gap of 2 may be used in appropriate combination.

1 is an overall configuration diagram of a laser beam printer which is an embodiment of an electrophotographic image forming apparatus. The figure which shows the one end surface side explaining a laminated type organic photoreceptor drum. The figure which shows the one end surface side explaining a laminated type organic photoreceptor drum similarly. The figure which shows the one end surface side explaining a laminated type organic photoreceptor drum similarly. The side view which shows the process cartridge in this embodiment. FIG. 3 is a diagram illustrating a process cartridge mounting unit in the image forming apparatus main body. FIG. 4 is a partially enlarged view of a perspective view showing each part and each device constituting the process cartridge. FIG. 3 is a partial cross-sectional view in a planar direction when the process cartridge is viewed from above. FIG. 4 is a partially enlarged view of a perspective view showing each part and each device constituting the process cartridge. The elements on larger scale of the perspective view of a passive coupling and a drive coupling. The elements on larger scale of the longitudinal cross-sectional view of a drive coupling and a photoreceptor drum. The schematic diagram which shows a connection convex part and a connection recessed part. FIG. 6 is a partial cross-sectional view in a plane direction schematically showing the operation of the drive coupling and the operation of the charging electrode plate that moves along with the drive coupling. The flowchart which shows operation | movement of each step of a mounting | wearing bundling sequence.

Explanation of symbols

1 Process Cartridge 101 Cartridge Cover 11 Photosensitive Drum (Electrophotographic Photoconductor)
DESCRIPTION OF SYMBOLS 110 Drum cylinder 11a Conductive support 11b Charge generation layer 11c Charge transport layer 111 Drum shaft 111a Coupling part 112 Conducting plate 12 Charging roller (conductive member)
121 Charging electrode plate (electrode member)
13 Developing means 131 Developing roller (conductive member)
132 Developing blade 133 Developing electrode plate (electrode member)
14 Cleaning Means 141 Cleaning Member 141a Cleaning Support Sheet Metal A Apparatus Main Body (Image Forming Apparatus Main Body)
400 Cartridge cover 41 Drive coupling 41a Connecting portion 41b Rotating shaft 42 Charging contact 43 Development contact

Claims (7)

In a process cartridge detachable from an electrophotographic image forming apparatus main body for forming an image on a recording medium,
An electrophotographic photoreceptor carrying an electrostatic latent image;
A conductive member disposed in the vicinity of the electrophotographic photoreceptor;
Moving between a first position where the electrophotographic photosensitive member and the conductive member are electrically short-circuited and a second position where the electrophotographic photosensitive member and the conductive member are electrically opened. Possible electrode members;
A process cartridge.   2. The process cartridge according to claim 1, wherein the conductive member is a process unit that acts on the electrophotographic photosensitive member.   3. The process according to claim 2, wherein at least one of the process means is a charging roller that is charged with a charging bias voltage by a bias applying means provided in a main body of the image forming apparatus and charges the electrophotographic photosensitive member. cartridge.   3. The process according to claim 2, wherein at least one of the process means is a developing roller that is applied with a developing bias voltage by a bias applying means provided in a main body of the image forming apparatus and acts on the electrophotographic photosensitive member. cartridge.   5. The method according to claim 2, wherein when the electrode member is located at the second position, the process means is electrically connected directly or indirectly to the bias applying means via the electrode member. The process cartridge according to claim 1. In an image forming apparatus that can be transported in a state where a process cartridge is mounted on an electrophotographic image forming apparatus main body that forms an image on a recording medium,
An electrophotographic photosensitive member carrying an electrostatic latent image, a conductive member disposed in the vicinity of the electrophotographic photosensitive member, and a first state in which the electrophotographic photosensitive member and the conductive member are electrically short-circuited. A process cartridge having a position and an electrode member movable between a second position in a state where the electrophotographic photosensitive member and the conductive member are electrically opened;
A mounting means for detachably mounting the process cartridge;
Have
The image forming apparatus, wherein the process cartridge is transported in a state where the electrode member is located at the first position.   The image forming apparatus according to claim 6, wherein the electrode member is positioned at the second position when an image forming process is performed in the image forming unit.

Images