JP2010224117A - Color electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color electrophotographic image forming apparatus capable of raising operability of a cartridge support member. <P>SOLUTION: In an image forming apparatus 50 including: electrostatic charge contacts 37Y-37K; a ground spring 36; a ground contact 39; power supply contacts 42Y-42K; a ground spring 46; a ground contact 45; a tray 61; and a door 31, the ground spring 36, the ground contact 39, and the ground spring 46, and the ground contact 45 ground the electrostatic charge contacts 37Y-37K and the power supply contacts 42Y-42K before a photoreceptor drum 1 and a belt 13 are pulled apart based on an opening operation of the door 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a color electrophotographic image forming apparatus in which a plurality of process cartridges are detachably attached to an apparatus body to form an image on a recording medium.

  Conventionally, a color electrophotographic image forming apparatus as described in Patent Document 1 is known as a process cartridge replacement mechanism for an image forming apparatus main body. The color electrophotographic image forming apparatus described in Patent Document 1 has a configuration in which a plurality of process cartridges are accommodated in a tray (cartridge support member), and the process cartridges are replaced in a state where the tray is pulled forward.

Japanese Patent Laid-Open No. 2007-121983

  However, if the photosensitive drum and the intermediate transfer belt are in the attracting state when the tray is pulled out, the operation force when pulling out the tray is increased.

  SUMMARY An advantage of some aspects of the invention is that it provides a color electrophotographic image forming apparatus in which the operability of a cartridge support member is improved.

  In order to achieve the above object, a color electrophotographic image forming apparatus according to the present invention includes a plurality of process cartridges having an electrophotographic photosensitive drum, a cartridge contact for supplying power to the process cartridge, and a cartridge contact for grounding the cartridge contact. An earthing means, an intermediate transfer belt to which a toner image is transferred from the electrophotographic photosensitive drum, and an inner peripheral side of the intermediate transfer belt are arranged to transfer the toner image on the electrophotographic photosensitive drum to the intermediate transfer belt. A transfer means for supplying power, a transfer contact for supplying power to the transfer means, a transfer contact grounding means for grounding the transfer contact, and an inner side that supports the process cartridge and the process cartridge is located inside an image forming apparatus main body. Position and the outside of the apparatus main body to which the process cartridge can be attached and detached. A color electrophotographic image, comprising: a cartridge support member movable between outer positions, and an opening / closing member that opens and closes an opening of a passage path through which the cartridge support member passes during movement between the inner position and the outer position. In the forming apparatus, before the electrophotographic photosensitive drum and the intermediate transfer belt are separated from each other based on the opening operation of the opening / closing member, the cartridge contact grounding means and the transfer contact grounding means are the cartridge contact and the transfer contact. Is grounded.

  As described above, according to the present invention, the cartridge contact grounding means and the transfer contact grounding means are connected to the cartridge contact and transfer contact before the electrophotographic photosensitive drum and the intermediate transfer belt are separated based on the opening operation of the opening / closing member. Is grounded. Therefore, before the user pulls out the cartridge support member and replaces the process cartridge, the electrophotographic photosensitive drum and the intermediate transfer belt are grounded. As described above, after the electrophotographic photosensitive drum and the intermediate transfer belt are grounded and the adsorption force is reduced, the electrophotographic photosensitive drum and the intermediate transfer belt are separated. As a result, the operability of the cartridge support member can be improved.

1 is a perspective view of a color electrophotographic image forming apparatus according to a first embodiment of the present invention. It is sectional drawing of the color electrophotographic image forming apparatus shown in FIG. It is a perspective view of a cartridge. It is a perspective view which shows the state of a tray when a door is located in a closed position. (A) It is a side view which shows the state of a tray when a door is located in a closed position. (B) It is a side view which shows the state of a tray when a door opens to the middle position. (C) It is a side view which shows the state of a tray when a door moves to an open position. (D) It is a side view which shows the process of the tray pulled out by the user after a door moves to an open position. It is sectional drawing which shows the state of a tray when a door is further opened rather than an open position. It is a perspective view which shows the state of the tray at the time of the door located in the closed position based on 2nd Embodiment of this invention. (A) It is a side view which shows the state of a tray when a door is located in a closed position. (B) It is sectional drawing which shows the state of a tray when a door opens to the middle position. (C) It is sectional drawing which shows the state of a tray when a door opens to the middle position. (D) It is a side view which shows the state of a tray when a door moves to an open position. It is sectional drawing of the exchange mechanism of the cartridge which concerns on other embodiment.

  Hereinafter, a color electrophotographic image forming apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. However, since the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions, there are particularly specific descriptions. As long as there is not, it is not the meaning which limits the scope of the present invention only to them.

  A color electrophotographic image forming apparatus described later forms a color image on a recording medium using an electrophotographic image forming process. Examples of the color electrophotographic image forming apparatus include a color electrophotographic copying machine, a color electrophotographic printer (for example, a color laser beam printer, a color LED printer), a color facsimile apparatus, a color word processor, and the like.

  A recording medium described later is an image on which an image is formed by an electrophotographic image forming apparatus, and includes, for example, paper, an OHP sheet, and the like.

  The cartridge to be described later is, for example, a process cartridge or a developing cartridge, which is detachably mounted on the main body of the electrophotographic image forming apparatus and contributes to an image forming process for forming an image on a recording medium.

  The process cartridge described later is a cartridge in which at least one of a charging unit, a developing unit, and a cleaning unit as a process unit and an electrophotographic photosensitive drum are integrally formed and detachably mounted on the main body of the electrophotographic image forming apparatus. It is a thing. Accordingly, the process cartridge includes one in which the developing means as the process means and the electrophotographic photosensitive drum are integrally formed as a cartridge and detachably attached to the main body of the electrophotographic image forming apparatus. Further, the process cartridge includes a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive drum as process units are integrated into a cartridge and detachably mounted on the apparatus main body.

  A process cartridge that integrally includes an electrophotographic photosensitive drum and developing means is referred to as a so-called integral type. A process cartridge that integrally includes an electrophotographic photosensitive drum and process means other than the developing means is referred to as a so-called separation type. The process cartridge can be attached to and detached from the apparatus main body by the user himself. Therefore, maintenance of the apparatus main body can be easily performed. The process means acts on the electrophotographic photosensitive drum.

  The developing cartridge has a developing roller, and stores the developer (toner) used to develop the electrostatic latent image formed on the electrophotographic photosensitive drum by the developing roller, and is removable from the main body. It is to be attached to. In the case of the developing cartridge, the electrophotographic photosensitive drum is attached to the apparatus main body or a cartridge support member described later. Alternatively, the electrophotographic photosensitive drum is provided in a so-called separation type process cartridge (in this case, the process cartridge does not have a developing unit). Note that the developing cartridge can also be attached to and detached from the apparatus main body by the user. Therefore, maintenance of the apparatus main body can be easily performed.

  Therefore, the cartridge includes a so-called integral type or a so-called separation type process cartridge. The cartridge includes a case where a so-called separation type process cartridge and a developing cartridge are used as a pair. In addition, the cartridge includes a case where the electrophotographic photosensitive drum is fixedly attached to the apparatus main body or a cartridge support member which will be described later, and the developing cartridge is detachably used so as to act on the electrophotographic photosensitive drum. .

(First embodiment)
(Overall schematic configuration of image forming apparatus)
First, an overall schematic configuration of a color electrophotographic image forming apparatus (hereinafter referred to as an image forming apparatus) 50 according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a perspective view showing the configuration of an image forming apparatus 50 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of the image forming apparatus 50. As shown in FIGS. 1 and 2, the image forming apparatus 50 is a four-color full-color laser printer using an electrophotographic process. The image forming apparatus 50 forms an image on a recording medium (paper) based on an electrical image signal input from an external host device (not shown) such as a personal computer, an image reader, or a counterpart facsimile machine.

  In the following description, with respect to the image forming apparatus 50 or the color electrophotographic image forming apparatus main body (hereinafter referred to as the apparatus main body) 50A, the front side (front side) is the side on which the door 31 that is an “opening / closing member” is disposed. . The rear side (back side) is the opposite side. The front-rear direction is a direction from the rear side of the apparatus main body 50A toward the front side (front direction) and the opposite direction (rear direction). Left and right are left or right when the apparatus main body 50A is viewed from the front side. The left-right direction is a direction from left to right (left direction) and the opposite direction (right direction). Further, the apparatus main body 50A has a configuration in which each cartridge P is removed from the image forming apparatus 50.

  Inside the apparatus main body 50A, first to fourth four cartridges PY, PM, PC, PK are arranged in a horizontal direction from the rear side to the front side (in-line configuration, tandem type). The cartridges have the same configuration except that the color of the contained toner is different.

  Each of these plural, ie, four cartridges P (PY, PM, PC, PK) has a photosensitive drum 1 which is an electrophotographic photosensitive drum. The cartridges PY to PK are configured to be detachable from a drawer tray (hereinafter referred to as a tray) 61 that is a cartridge support member. The tray 61 supports the cartridge P and is configured to be movable between an inner position I (see FIG. 2) and an outer position O (see FIG. 6). The inner position I (see FIG. 2) is located inside the apparatus main body 50A where the cartridge P can form an image. The outer position O (see FIG. 6) is located outside the apparatus main body 50A to which the cartridge P can be attached and detached.

  FIG. 3 is a perspective view showing the configuration of the cartridge P. FIG. FIG. 3A is a perspective view of the configuration of the cartridge as viewed from the drive side. FIG. 3B is a perspective view of the configuration of the cartridge P as viewed from the non-driving unit side. As shown in FIGS. 3A and 3B, the cartridge P includes a cartridge frame 5. The frame body 5 is provided with a flange 56 on the upper surface 5A. An exposure window 6 is provided on the upper surface 5A of the frame 5. An electrophotographic photosensitive drum (hereinafter referred to as a photosensitive drum) 1 is disposed inside the frame 5. Although not shown in FIGS. 3 (a) and 3 (b), as shown in FIGS. 1 and 2, the frame 5 is otherwise charged as a process means that acts on the photosensitive drum 1. A device 2, a developing device 3, and a cleaning device 4 are integrally provided. The charger 2 is a contact charging roller. The developing device 3 has a developing roller 3a, and a developer (toner) is accommodated in the developer container. The cleaning device 4 is of a blade type. In FIG. 3, 51 is a drive side bearing portion, 52 is a bearing portion, 53 is a coupling fitting portion, and 55 is a cartridge potential contact.

  Here, referring again to FIG. 2, in the first cartridge PY, the developing device 3 contains yellow (Y) toner and forms a Y-color toner image on the surface of the photosensitive drum 1. In the second cartridge PM, magenta (M) toner is accommodated in the developing device 3, and an M color toner image is formed on the surface of the photosensitive drum 1. The third cartridge PC stores cyan (C) toner in the developing device 3 and forms a C-color toner image on the surface of the photosensitive drum 1. The fourth cartridge PK stores black (K) toner in the developing device 3 and forms a K-color toner image on the surface of the photosensitive drum 1.

  A laser scanner unit 11 is provided above each cartridge P. The unit 11 outputs laser light L modulated in accordance with image information of each color input from the external host device, and scans and exposes the drum surface of each cartridge P through the exposure window 6 provided on the upper surface of the frame 5. .

  Below each cartridge P, an intermediate transfer belt unit 12 is disposed. The belt unit 12 includes a flexible endless belt 13 made of a dielectric material as an intermediate transfer belt. Further, the belt unit 12 includes a driving roller 14, a turn roller 15, and a tension roller 16 that suspends and stretches the belt 13 to circulate. The drive roller 14 and the tension roller 16 are disposed on the rear side inside the apparatus main body 50A. The turn roller 15 is disposed on the front side inside the apparatus main body 50A. The lower surface of the photosensitive drum 1 included in each cartridge P is in contact with the upper belt surface of the belt 13. Inside the belt 13, four primary transfer rollers 17 are arranged at positions facing the photosensitive drum 1 of each cartridge P with respect to the belt 13. A secondary transfer roller 22 is brought into contact with the driving roller 14 via the belt 13.

  A feeding unit 18 is disposed below the belt unit 12. The unit 18 includes a feeding tray 19, a feeding roller 20, a separation pad 21, and the like. The feeding tray 19 can be freely inserted and removed from the front side of the apparatus main body 50A (front loading).

  A fixing device 23 and a discharge roller pair 24 are disposed on the upper rear side in the apparatus main body 50A. The upper surface of the apparatus main body 50 </ b> A is a discharge tray 25. The fixing device 23 has a fixing film assembly 23a and a pressure roller 23b. The roller pair 24 is a roller 24a and a roller 24b.

  Each cartridge P in a state of being mounted at the mounting position inside the apparatus main body 50A is held in a state of being pressed by a pressing member described later and fixed to a predetermined positioning portion. Further, the drive output unit on the side of the apparatus main body 50A is coupled to the drive input unit of the cartridge P. In addition, the power supply system on the apparatus main body 50A side is electrically connected to the electrical contacts of the cartridge P.

  The operation for forming a full-color image is as follows. The photosensitive drum 1 of each of the first to fourth cartridges P is rotationally driven at a predetermined control speed in the counterclockwise direction indicated by the arrow. The belt 13 is also rotationally driven at a speed corresponding to the speed of the photosensitive drum 1 in the clockwise direction of the arrow (forward direction with respect to the drum rotation). The unit 11 is also driven. In synchronism with this drive, the charger 2 uniformly charges the surface of the photosensitive drum 1 to a predetermined polarity and potential in each cartridge P at a predetermined control timing. The unit 11 scans and exposes the surface of each photosensitive drum 1 with a laser beam L modulated according to the image signal of each color. Thereby, an electrostatic latent image corresponding to the image signal of the corresponding color is formed on the surface of each photosensitive drum 1. The formed electrostatic latent image is developed as a toner image by the developing device 3.

  By the electrophotographic image forming process operation as described above, a Y toner image corresponding to the yellow component of the full color image is formed on the photosensitive drum 1 of the cartridge PY, and the toner image is primarily transferred onto the belt 13. An M color toner image corresponding to the magenta component of the full color image is formed on the photosensitive drum 1 of the cartridge PM, and the toner image is primary-transferred superimposed on the Y color toner image already transferred on the belt 13. The A C color toner image corresponding to the cyan component of the full color image is formed on the photosensitive drum 1 of the cartridge PC, and the toner image is superimposed on the Y color + M color toner image already transferred onto the belt 13 to be primary. Transcribed. A K color toner image corresponding to the black component of the full color image is formed on the photosensitive drum 1 of the cartridge PC, and the toner image is superimposed on the Y color + M color + C color toner image already transferred onto the belt 13. The primary transfer. In this way, a four-color full-color unfixed toner image of Y color + M color + C color + K color is synthesized and formed on the belt 13.

  In each cartridge P, the transfer residual toner remaining on the surface of the photosensitive drum 1 after the primary transfer of the toner image to the belt 13 is removed by the cleaning device 4.

  On the other hand, the roller 20 is driven at a predetermined control timing. As a result, the sheet (recording medium) S stacked on the feeding tray 19 is separated and fed by the cooperation of the roller 20 and the separation pad 21, and the secondary transfer roller 22 and the belt 13 are separated. It is introduced into the nip portion (secondary transfer nip portion). As a result, the four color superimposed toner images on the belt 13 are sequentially transferred onto the surface of the sheet S in a batch as the sheet S is nipped and conveyed through the nip portion.

  The sheet S is separated from the surface of the belt 13 and introduced into the fixing device 23, and is heated and pressurized at the fixing nip portion. As a result, the color toner images are mixed and fixed onto the paper S. Then, the sheet S exits the fixing device 23 and is discharged onto the discharge tray 25 by the roller pair 24 as a full-color image formed product.

  In this embodiment, the secondary transfer residual toner remaining on the surface of the belt 13 after paper separation is electrostatically adhered to the surface of the photosensitive drum 1 in the primary transfer portion of the first cartridge PY, for example, and cleaning is performed. It is removed by the vessel 4.

(Cartridge replacement method)
Next, the cartridge replacement mechanism 100 will be described with reference to FIGS.

  FIG. 2 is a cross-sectional view illustrating a configuration of the image forming apparatus 50. As shown in FIG. 2, as each of the first to fourth cartridges P is used for image formation, the developer (toner) accommodated in the developing device 3 is consumed. Then, when the developer is consumed to such an extent that an image with satisfactory quality cannot be formed for the user who purchased the cartridge, the cartridge is replaced with a new cartridge P.

  For this reason, for example, a means (not shown) for detecting the remaining amount of developer in each cartridge P is provided, and the control unit sets the detected remaining amount value to a preset threshold value for cartridge life warning or life warning. Let them compare. For the cartridge P whose detected remaining amount value is smaller than the threshold value, a life warning or life warning for the cartridge P is displayed on the display unit. This prompts the user to prepare a new cartridge P for replacement, or prompts the user to replace the cartridge P to maintain the quality of the output image.

  In the image forming apparatus 50 of the present embodiment, the replacement of the cartridge P is a system in which the cartridge P is placed on the drawer tray (cartridge support member) 61 and exchanged by front access in order to improve usability.

  That is, on the front side of the image forming apparatus 50, an opening 30 through which the cartridge P passes is provided in order to insert the cartridge P into the apparatus main body 50A and to remove the cartridge P from the apparatus main body 50A. .

  And the door (opening-closing member) 31 which can move between the closed position which closes this opening part 30, and the open position which opens the opening part 30 is provided. The door 31 opens and closes around a door shaft 32.

  FIG. 4 is a perspective view showing a state of the tray 61 when the door 31 is arranged at the closed position (90-degree position). Fig.5 (a) is a side view which shows the state of the tray 61 when the door 31 is arrange | positioned in a closed position (90 degree position). The door 31 is configured to open and close the opening 30 of the passage path 29 through which the tray 61 can pass during movement between the inner position I and the outer position O. As shown in FIGS. 4 and 5A, the door 31 is provided with a link lever 33. The lever 33 engages with one end 34A of the link member 34 on the cartridge side and one end 40A of the link member 40 on the belt side. Further, the other end 34B of the link member 34 engages with a ground rod (cartridge ground means moving member) 35 on the cartridge side. The other end 40B of the link member 40 engages with a belt-side earth rod (belt earth means moving member) 41.

  The ground rod 35 and the ground rod 41 are held by the apparatus main body 50A so as to be horizontally movable (not shown). The earth rod 35 has four spring protrusions 35J that protrude upward at predetermined intervals. An earth spring (cartridge contact earth means) 36 on the cartridge side is attached to the earth rod 35. At the time of attachment, the ground spring (conductive elastic member) 36 is hooked on the spring projection 35J of the ground rod 35. Therefore, the earth rod 35 can move integrally with the earth spring 36. The ground spring 36 is bent downward in a convex shape, and is disposed so as to be able to contact a charging contact 37 on the cartridge side described later based on the movement of the ground rod 35.

  The earth rod 41 has four spring protrusions 41J that protrude upward at predetermined intervals. A belt-side ground spring (transfer contact grounding means) (conductive elastic member) 46 is attached to the ground rod 41. In the attachment, the ground spring 46 is hooked on the spring convex portion 41J of the ground rod 41. Therefore, the earth rod 41 can move integrally with the earth spring 46. The ground spring 46 is bent downward and convex, and is arranged so as to come into contact with a power supply contact 42 on the belt side described later based on the movement of the ground rod 41.

  The apparatus main body 50A includes a cartridge-side charging contact (cartridge contact) 37 (37Y, 37M, 37C, 37K) that supplies power to the charging roller of each cartridge P, and a cartridge-side ground contact (cartridge contact grounding means) 39. Is attached. The ground contact 39 is disposed so as to always contact the ground spring 36. That is, when the tray 61 moves between the inner position I and the outer position O, the charging contact 37 (37Y to 37K) is always in contact with the earth spring 36. For this reason, as the “cartridge contact grounding means”, there are the above-described ground spring 36 and ground contact 39, which are configured to ground the charging contact 37.

  Further, a relay contact 38 (38Y, 38M, 38C, 38K) that electrically relays between the charging contact 37 and the cartridge P is attached to the tray 61. When the door 31 is disposed at the closed position, the charging contacts 37Y, 37M, 37C, and 37K and the relay contacts 38Y, 38M, 38C, and 38K are disposed so as to be in contact with each other. Thereby, each cartridge P can be charged. That is, the charging contact 37Y and the relay contact 38Y, the charging contact 37M and the relay contact 38M, the charging contact 37C and the relay contact 38C, and the charging contact 37K and the relay contact 38K are electrically connected.

  An endless belt (intermediate transfer belt) 13 to which the toner image is transferred from the photosensitive drum 1 is disposed below the passage path 29 for the tray 61 to move between the inner position I and the outer position O. . A transfer roller (transfer means) 44 (44Y, 44M, 44C, 44K) for transferring the toner image on the photosensitive drum 1 to the belt 13 is disposed on the inner peripheral side of the belt 13.

  A belt-side power supply contact (transfer contact) 42 (42Y, 42M, 42C, 42K) for supplying power to the transfer roller 44 and a belt-side ground contact (transfer contact grounding means) 45 are attached to the apparatus main body 50A. It has been. The ground contact 45 is disposed so as to always contact a belt-side ground spring (conductive elastic member) 46. That is, when the tray 61 moves between the inner position I and the outer position O, the power supply contact 42 always contacts the earth spring 46. For this reason, the “transfer ground contact means” includes the above-described ground spring 46 and ground contact 45, which are configured to ground the power supply contact 42.

  Further, a relay contact 43 (43Y, 43M, 43C, 43K) that electrically relays between the power supply contact 42 and the transfer roller 44 is attached to the belt unit 12 having the transfer roller 44. In FIGS. 4 and 5A, the ground rod 41 and the ground spring 46 are partially cut so that the power feeding portion on the belt side can be confirmed. The power supply contact 42M disposed in the apparatus main body 50A is in contact with the relay contact 43M. Further, the relay contact 43M is in contact with the transfer roller 44M and supplies power to the transfer roller 44M.

  Therefore, when the door 31 is disposed at the closed position, the power supply contact 42 and the relay contact 43 are disposed so as to be in contact with each other. As a result, the transfer roller 44 can supply power.

  Then, before the photosensitive drum 1 and the belt 13 are separated based on the opening operation of the door 31, the ground spring 36 and the ground contact 39 are configured to ground the charging contact 37. Further, before the photosensitive drum 1 and the belt 13 are separated from each other based on the opening operation of the door 31, the ground spring 46 and the ground contact 45 are configured to ground the power feeding contact 42.

  FIG. 5B is a cross-sectional view showing a state of the tray 61 when the door 31 is opened to a midway position (45 ° position). As shown in FIG. 5B, when the door 31 opens, the ground rod 35 is pulled by the link member 34 and moves horizontally to the right. Then, the ground spring 36 on the exchange mechanism 100 side comes into contact with the charging contact 37 on the apparatus main body 50A side, and the electric charge remaining in the cartridge P is removed. Similarly, the earth rod 41 is pulled by the link member 40 and moves horizontally in the right direction. Then, the ground spring 46 on the exchange mechanism 100 side comes into contact with the power supply contact 42 on the apparatus main body 50 </ b> A side, and the electric charge remaining on the transfer roller 44 is removed.

  FIG. 5C is a side view showing a state of the tray 61 when the door 31 is moved to the open position (0 degree position). As shown in FIG. 5C, the door 31 is further opened to the open position (0 degree position). At this point, the photosensitive drum 1 and the belt 13 are in contact.

  FIG. 5D is a side view showing the process of the tray 61 pulled out by the user after the door 31 has moved to the open position (0 degree position). As shown in FIG. 5D, the tray 61 is pulled out while changing its direction gradually in the order of the diagonally upward direction E and the horizontal right direction F. At this time, since the photosensitive drum 1 and the belt 13 are grounded, the attractive force is reduced and they are smoothly separated without being attracted to each other.

  FIG. 6 is a cross-sectional view showing a state of the tray 61 when the door (opening / closing member) 31 is further opened from the open position (0 degree position). As shown in FIG. 6, when the tray 61 is moved from the inner position I to the outer position O, the door 31 is further opened to the opening limit position (−20 degrees position). At this time, the tray 61 is pulled out to the outer position O, that is, the replacement position where the cartridge P is replaced, along the guide member 62 provided on the inner surface of the apparatus main body 50A. Each cartridge P is exchanged at this outer position O. At this time, the residual charge inside the cartridge P is removed. Therefore, even if the user touches the charging contact of the cartridge P, the user does not receive an impact.

  In addition, it is assumed that the user places a cartridge P charged with static electricity in the tray 61 and inserts the tray 61 into the apparatus main body 50A. Even in this case, since the charging contact of the cartridge P falls to the ground, the electric circuit (not shown) is not damaged.

  As described above, according to the replacement mechanism 100, the ground spring 36 and the ground rod 35 ground the cartridge P before the photosensitive drum 1 and the belt 13 are separated by the opening operation of the door 31. Therefore, before the user pulls out the tray 61 and replaces the cartridge P, the photosensitive drum 1 is grounded. Similarly, the earth spring 46, the earth rod 41, and the earth contact 45 ground the belt 13 before the photosensitive drum 1 and the belt 13 are separated based on the opening operation of the door 31. Therefore, before the user pulls out the tray 61 and replaces the cartridge P, the belt 13 is grounded. As described above, after the photosensitive drum 1 and the belt 13 are grounded and the suction force is reduced, the photosensitive drum 1 and the belt 13 are separated. As a result, the operability of the tray 61 is improved, and the cartridge P can be exchanged without the user receiving an electric shock.

  While the tray 61 moves between the inner position I and the outer position O, charging of the cartridge P and the belt 13 is suppressed. As a result, the tray 61 is easily pulled out.

(Second Embodiment)
Next, a cartridge replacement mechanism 200 applied to the color electrophotographic image forming apparatus according to the second embodiment of the present invention will be described with reference to FIGS.

  Of the configuration of the exchange mechanism 200 of the second embodiment, the same configurations and effects as those of the exchange mechanism 100 of the first embodiment are denoted by the same reference numerals and description thereof is omitted as appropriate. Since the second embodiment can be applied to the same image forming apparatus as that of the first embodiment, the entire description of the image forming apparatus will be omitted as appropriate.

  FIG. 7 is a perspective view showing the state of the tray 61 when the door 31 is located at the closed position (90-degree position). FIG. 8A is a side view showing a state of the tray 61 when the door 31 is located at the closed position (90-degree position). As shown in FIGS. 7 and 8A, the exchange mechanism 200 is different from the exchange mechanism 100 in the following points. That is, the exchange mechanism 200 is different in that an earth rod 85 is used instead of the earth rod 35. Further, the exchange mechanism 200 is different in that instead of the cartridge P, cartridges PY2, PM2, PC2, and PK2 are used.

  The cartridge-side earth rod 85 is provided with an upward convex surface 51 (51E, 51F, 51G, 51H) as an “upward convex surface protruding upward” which is a “pressing surface” at predetermined intervals. The convex surface 51 can press the cartridges PY2 to PK2 upward.

  On the other hand, the cartridges PY2, PM2, PC2, and PK2 have downward convex surfaces 52 (52E, 52F, 52G, and 52H) as “downward convex surfaces that project downward”, which are “pressed surfaces” at predetermined intervals. Is provided. The convex surface 52 can be pressed by the convex surface 51.

  When the door 31 is located at the closed position (90-degree position), each convex surface 51 and each convex surface 52E are arranged in a state in which contact is released. That is, the convex surface 51 and the convex surface 52E are in a state of being separated from each other. However, as the door 31 moves to the open position (0-degree position), each convex surface 51 and each convex surface 52 shift to a contacted state, and the contact force is strengthened.

  FIG. 8B is a cross-sectional view showing the state of the tray 61 when the door 31 is opened to the midway position (about 60 degrees position). As shown in FIG. 8B, when the door 31 opens, the ground rod 85 is pulled by the link member 34 and moves horizontally to the right. Then, the ground spring 36 on the replacement mechanism 200 side contacts the charging contact 37 (37Y to 37K) on the apparatus main body 50A side. Then, the charge remaining in the cartridges PY2, PM2, PC2, and PK2 is removed. Similarly, the earth rod 41 is pulled by the link member 40 and moves horizontally in the right direction. Then, the ground spring 46 on the exchange mechanism 200 side contacts the power supply contact 42 (42Y to 42K) on the apparatus main body 50A side, and the electric charge remaining on each transfer roller 44 is removed.

  FIG. 8C is a cross-sectional view showing the state of the tray 61 when the door 31 is opened to the middle position (about 30 degrees position). As shown in FIG. 8C, when the door 31 is opened, each convex surface 51 presses while sliding up the slope of each convex surface 52. The cartridges PY <b> 2 to PK <b> 2 are lifted by the pressed state of the slope of the ground rod 85 and the slopes of the cartridges PY <b> 2 to PK <b> 2. Then, the photosensitive drums 1Y to 1K provided below the cartridges PY2 to PK2 are pulled away from the belt 13. Thus, the earth rod 85 moves the earth spring 36. Thus, the convex surfaces 51E to 51H press the convex surfaces 52E to 52H to separate the photosensitive drum 1 and the belt 13 from each other.

  FIG. 8D is a side view showing a state of the tray 61 when the door 31 is moved to the open position (0 degree position). As shown in FIG. 8D, the door 31 is further opened to the open position (0 degree position). In the process of opening the door 31 in this way, each convex surface 52 is released from pressing while sliding down along the slope of each convex surface 51. The cartridges PY <b> 2 to PK <b> 2 are lowered due to the pressed release state of the slope of the ground rod 85 and the slopes of the cartridges PY <b> 2 to PK <b> 2. Then, the photosensitive drums 1Y to 1K provided under the cartridges PY2 to PK2 come into contact with the belt 13 again.

  Thereafter, the exchange mechanism 200 operates in the same manner as the exchange mechanism 100 in the first embodiment described above (see FIG. 5D). As shown in FIG. 8D, after the door 31 is moved to the open position (0 degree position), the user pulls out the tray 61 while changing its direction gradually in the order of the diagonally upward direction E and the horizontal right direction F. To go. At this time, the photosensitive drum 1 and the belt 13 are once separated. Therefore, the adsorption power of both is reduced, and they are smoothly separated without adsorbing each other.

  Further thereafter, the exchange mechanism 200 operates in the same manner as the exchange mechanism 100 in the first embodiment described above (see FIG. 6). When the tray 61 is moved from the inner position I to the outer position O, the door 31 is further opened to the opening limit position (−20 degrees). At this time, the tray 61 is pulled out to the outer position O, that is, the replacement position for replacing the cartridge P along the guide member 62 (FIG. 6) provided on the inner surface of the apparatus main body 50A. At this outer position O, the cartridges PY2 to PK are exchanged. At this time, the residual charges inside the cartridges PY to PK are removed. Therefore, even if the user touches the charging contacts of the cartridges PY to PK, the user does not receive an impact.

  In addition, it is assumed that the user puts the electrostatically charged cartridges PY2 to PK2 in the tray 61 and inserts the tray 61 into the apparatus main body 50A. Even in this case, the charging contacts of the cartridges PY2 to PK2 are grounded. Therefore, the electric circuit provided in the apparatus main body 50A is not damaged.

  As described above, according to the replacement mechanism 200, the ground spring 36 and the ground rod 85 ground the cartridges PY2 to PK2 before the photosensitive drum 1 and the belt 13 are separated by the opening operation of the door 31. Accordingly, the photosensitive drum 1 is grounded before the user pulls out the tray 61 and replaces the cartridges PY2 to PK2. Similarly, the earth spring 46, the earth rod 41, and the earth contact 45 ground the belt 13 before the photosensitive drum 1 and the belt 13 are separated based on the opening operation of the door 31. Therefore, before the user pulls out the tray 61 and replaces the cartridges PY2 to PK2, the belt 13 is grounded. As described above, after the photosensitive drum 1 and the belt 13 are grounded and the suction force is reduced, the photosensitive drum 1 and the belt 13 are separated. As a result, the operability of the drawer tray 61 can be improved.

  While the drawer tray 61 moves between the inner position I and the outer position O, charging of the cartridges PY2 to PK2 and the belt 13 is suppressed. As a result, the drawer tray 61 is easily pulled out.

  The convex surfaces 51E to 51H of the earth rod 85 press the convex surfaces 52E to 52H of the cartridges PY to PK, and the photosensitive drum 1 and the belt 13 are separated from each other while being grounded. For this reason, the photosensitive drum 1 and the belt 13 are in a state in which the mutual attractive force is suppressed to a minimum. As a result, the drawer tray 61 that supports the cartridges PY to PK is efficiently pulled out from the apparatus main body 50A.

(Modified embodiment)
FIG. 9 is a cross-sectional view showing a configuration of a cartridge exchange mechanism 300 according to a modified embodiment of the second embodiment. In the exchange mechanism 200 in the second embodiment, the interval between the convex surfaces 53 of the ground rod 85 is set to a constant dimension. Further, in the replacement mechanism 200, the intervals between the convex surfaces 54 of the cartridges PY3, PM3, PC3, and PK3 are set to constant dimensions. However, it is not limited to the above embodiment. For example, as shown in FIG. 9, in the exchange mechanism 300, the interval between the upward convex surfaces 53 (53E, 53F, 53G, 53H) of the cartridge-side earth rod 95 is set to an irregular dimension. In the replacement mechanism 300, the intervals between the downward convex surfaces 54 (54E, 54F, 54G, 54H) of the cartridges PY3, PM3, PC3, and PK3 are set to irregular dimensions.

  Temporarily, the position where each of the convex surfaces 53E to 53H presses each of the convex surfaces 54E to 54H with the maximum load is set as the maximum pressing points 53E1 to 53H1. Further, the positions at which the convex surfaces 54E to 54H are pressed from the convex surfaces 53E to 53H are set as the maximum pressed points 54E1 to 54H1. In this case, the relative positions of the maximum pressing points 53E1 to 53H1 with respect to the maximum pressed points 54E1 to 54H1 are different for each combination of the convex surfaces 53E to 53H and the convex surfaces 54E to 54H.

  As described above, according to the exchange mechanism 300, any one of the convex surfaces 53E, 53F, 53G, and 53H and the convex surfaces 54E, 54F, 54G, and 54H is in the pressed state when any one is in the pressed state. Is set as follows. That is, the timing at which the respective convex surfaces 53E, 53F, 53G, and 53H press the corresponding convex surfaces 54E, 54F, 54G, and 54H can be shifted. Each of the cartridges PY3 to PK3 is pulled away from the belt 13 at different timings. As a result, the load required for opening and closing the door 31 is averaged and the maximum load is reduced.

  DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum (electrophotographic photosensitive drum), 13 ... Belt (intermediate transfer belt), 31 ... Door (opening / closing member), 35 ... Earth rod (cartridge earth means moving member), 36... Earth spring (cartridge contact grounding means), 37Y to 37K... Charging contact (cartridge contact), 39... Earth contact (cartridge contact grounding means), 41. ), 42Y to 42K... Feeding contact (transfer contact), 44Y to 44K... Transfer roller, 45... Ground contact (transfer contact grounding means), 46. ... Image forming apparatus, 50A ... Main body, 61 ... Tray, I ... Inside position, O ... Outside position, PY-PK, PY2-PK2, P 3~PK3 ··· cartridge

Claims (4)

A plurality of process cartridges having an electrophotographic photosensitive drum, a cartridge contact for supplying power to the process cartridge, a cartridge contact grounding means for grounding the cartridge contact, and an intermediate transfer for transferring a toner image from the electrophotographic photosensitive drum A belt, a transfer means disposed on the inner peripheral side of the intermediate transfer belt, for transferring the toner image of the electrophotographic photosensitive drum to the intermediate transfer belt, a transfer contact for supplying power to the transfer means, and the transfer contact. A transfer contact grounding means for grounding, an inner position where the process cartridge is supported and located inside the apparatus main body capable of forming an image, and an outer position where the process cartridge is removable. A cartridge support member movable between outer positions and the cart In the color electrophotographic image forming apparatus comprising a closing member Tsu di support member to open and close the opening of the passage way through during the movement between the inner position and the outer position, a
The cartridge contact grounding means and the transfer contact grounding means ground the cartridge contact and the transfer contact before the electrophotographic photosensitive drum and the intermediate transfer belt are separated from each other based on the opening operation of the opening / closing member. A color electrophotographic image forming apparatus.   When the cartridge supporting member moves between the inner position and the outer position, the cartridge contact and the cartridge contact grounding means are always in contact with each other, and the transfer contact and the transfer contact grounding means are always in contact with each other. The color electrophotographic image forming apparatus according to claim 1. A cartridge grounding means moving member capable of moving the cartridge contact grounding means;
A pressing surface formed on the cartridge earth means moving member and capable of pressing the process cartridge;
A pressed surface formed on the process cartridge and pressed against the pressing surface,
2. The apparatus according to claim 1, wherein when the cartridge grounding means moving member moves the cartridge contact grounding means, the pressing surface presses the pressed surface to separate the electrophotographic photosensitive drum from the intermediate transfer belt. The color electrophotographic image forming apparatus according to claim 1 or 2.   A position where each of the pressing surfaces presses each of the pressed surfaces with a maximum load is a maximum pressing point, and a position where each of the pressed surfaces is pressed with a maximum load from each of the pressing surfaces is a maximum pressing point. 4. The color electrophotographic image according to claim 3, wherein the relative position of the maximum pressing point with respect to the maximum pressed point is different for each combination of the pressing surface and the pressed surface. Forming equipment.

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