JP2010224122A - Color electrophotographic image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce impact applied to a unit 200 in which a plurality of cartridges 33 (33Y, 33M, 33C and 33K) are mounted and an apparatus body 100A, when the unit 200 is rotated in the apparatus body 100A, in a color electrophotographic image forming apparatus 100 in which the cartridges 33 are detachably attached to the apparatus body 100A, to form an image on a recording medium S. <P>SOLUTION: An energizing member 48 is provided between the unit 200 and the apparatus body 100A. When the unit 200 is rotated to an image forming position A, the energizing member 48 comes into contact with the unit 200, to absorb the impact. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  Here, the color electrophotographic image forming apparatus 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. The recording medium is an image on which an image is formed by an electrophotographic image forming apparatus, and includes, for example, paper, an OHT sheet, and the like.

  The cartridge is, for example, a process cartridge or a developing cartridge, and contributes to an image forming process for forming an image on a recording medium in a state where the cartridge is detachably attached to the main body of the electrophotographic image forming apparatus. is there. The process cartridge is one in which at least one of charging means, developing means, and cleaning means as process means and an electrophotographic photosensitive drum are integrally formed into a cartridge and detachably attached to the apparatus main body. Therefore, the process cartridge includes one in which the developing means as the process means and the electrophotographic photosensitive drum are integrally formed into a cartridge and detachably attached to the main body of the electrophotographic image forming apparatus. 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 integrally including an electrophotographic photosensitive drum and developing means is referred to as a so-called integrated 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. That is, a process cartridge in which the developing means is provided in a developing unit separate from the process cartridge and forms an image in a pair with the developing unit 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 contains a developer (toner) used for developing the electrostatic latent image formed on the electrophotographic photosensitive drum by the developing roller. Is to be detachably mounted. In the case of a developing cartridge, the electrophotographic photosensitive drum is attached to the apparatus main body or a cartridge support member. Alternatively, the electrophotographic photosensitive drum is provided in the so-called separation type process cartridge (in this case, the process cartridge does not have developing means). The developing cartridge can also be attached to and detached from the main body by the user himself. Therefore, maintenance of the apparatus main body can be easily performed.

  Therefore, the cartridge includes the so-called integral type or the 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. The cartridge includes a case where the electrophotographic photosensitive drum is fixedly attached to the apparatus main body or the cartridge support member, and the developing cartridge is detachably used so as to act on the electrophotographic photosensitive drum.

  As described above, conventionally, an electrophotographic image forming apparatus that forms an image on a recording medium using an electrophotographic image forming process is known. In this electrophotographic image forming apparatus, the process cartridge system described above is known. Alternatively, a developing cartridge system that is separate from the photosensitive drum and includes only the developing unit described above is known. The cartridge system includes the process cartridge system and the developing cartridge system described above. The process cartridge and the developing cartridge described above have a developer accommodating portion that accommodates a developer (toner) used for developing the electrostatic latent image.

  Patent Document 1 discloses an image forming apparatus capable of forming a color image. In this image forming apparatus, cartridge replacement work can be easily performed by pulling out a cartridge tray as a drawer member on which a plurality of cartridges are mounted in the same direction as the adjacent direction in which each cartridge is adjacent.

JP 2007-213025 A

  The present invention is a further development of the conventional configuration described above. An object of the present invention is to provide a color electrophotographic image forming apparatus in which an impact applied to an image forming unit or an apparatus main body is reduced when an image forming unit on which a cartridge is mounted is rotated in the apparatus main body. Another object of the present invention is to provide a color electrophotographic image forming apparatus capable of replacing the cartridge without retracting the image exposure apparatus when replacing the cartridge.

  A typical configuration of a color electrophotographic image forming apparatus according to the present invention for achieving the above object is a color electrophotographic image forming apparatus for forming a color image on a recording medium, and includes a plurality of developers. A cartridge, a transfer body for transferring the developer image formed on the electrophotographic photosensitive drum to the recording medium, and a cartridge mounting portion for mounting the cartridge; An image forming unit that is movable between an image forming position for forming an image with respect to the main body of the color electrophotographic image forming apparatus and a detachable position at which the cartridge different from the image forming position can be attached and detached. And an attachment for contacting both the image forming unit and the apparatus main body when the image forming unit moves from the attachment / detachment position to the image forming position. And having a member.

  According to the present invention, it is possible to provide a color electrophotographic image forming apparatus in which an impact applied to the image forming unit and the apparatus main body is reduced when the image forming unit on which the cartridge is mounted is rotated in the apparatus main body. Further, it is possible to provide a color electrophotographic image forming apparatus capable of replacing a cartridge without retracting the image exposure apparatus when replacing the cartridge.

1A is an external perspective view of an image forming apparatus according to an embodiment, and FIG. 1B is a vertical left side view of the image forming apparatus. FIG. 2 is an enlarged view of an image forming unit portion in FIG. (A) is a left perspective view of one photoconductor unit, and (b) is a perspective view of a photoconductor case in which a drum, a charging roller, and a cleaning blade are removed from the unit of (a). 3A is a right perspective view of the photosensitive member case of FIG. 3B, and FIG. 4B is an enlarged vertical sectional view of a removed developer discharge portion of the photosensitive member case. (A) is a right perspective view of one cartridge, (b) is a left perspective view. (A) is a left perspective view of the image forming unit, and (b) is a right perspective view. (A) is a left perspective view of the apparatus main body with the maintenance cover open, and (b) is a right perspective view. FIG. 6 is an explanatory diagram of a regulation unit on the apparatus main body side and a regulated unit on the image forming unit side. It is explanatory drawing of a maintenance button. FIG. 6 is an explanatory diagram of a procedure for mounting the image forming unit to the apparatus main body. (A) is explanatory drawing of the attachment procedure of the image forming unit with respect to an apparatus main body, (b) is a right side perspective view of a waste developer container. (A) is a left perspective view of a waste developer container, and (b) is a cross-sectional view taken along the section line (12)-(12) in (b) of FIG. FIG. 4 is an explanatory diagram of a procedure for attaching and detaching a waste developer container to and from an image forming unit. FIG. 4 is an explanatory diagram of a procedure for attaching and detaching a cartridge to and from an image forming unit. FIG. 4 is an explanatory diagram of a procedure for attaching and detaching a cartridge to and from an image forming unit. FIG. 4 is an explanatory diagram of a procedure for attaching and detaching a cartridge to and from an image forming unit. FIG. 4 is an explanatory diagram of a procedure for attaching and detaching a cartridge to and from an image forming unit. FIG. 4 is an explanatory diagram of a procedure for attaching and detaching a cartridge to and from an image forming unit. FIG. 4 is an explanatory diagram of a procedure for attaching and detaching a cartridge to and from an image forming unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

[Example]
<< Overall Schematic Configuration of Color Electrophotographic Image Forming Apparatus Example >>
FIG. 1A is an external perspective view of a color electrophotographic image forming apparatus (hereinafter referred to as an image forming apparatus) 100 in this embodiment. 2B is a longitudinal left side view of the image forming apparatus 100. FIG. The image forming apparatus 100 is a four-color full-color laser printer using an electrophotographic process. That is, the image forming apparatus 100 forms a full-color image on the recording medium (paper) S based on an electrical image signal input to the control circuit unit 300 from an external host device 400 such as a personal computer, an image reader, or a counterpart facsimile machine. .

  In the following description, with respect to the image forming apparatus 100, the front side (front side) is the side from which the feeding cassette 19 in which the recording medium S is stacked and stored is pulled out from the inside of the apparatus main body 100A to the outside. The rear side is the opposite side. The upper side is the side where the maintenance cover 10 is opened. The front-rear direction is a direction (front direction) from the rear side to the front side of the image forming apparatus and a reverse direction (rear direction). Left and right are left or right when the image forming apparatus 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). The longitudinal direction is the axial direction of the electrophotographic photosensitive drum or the developing roller. The apparatus main body 100A is an image forming apparatus portion excluding the cartridge 33 (33Y, 33M, 33C, and 33K) and the image forming unit 200. In the image forming apparatus of this embodiment, the right side is the driving side, and the left side is the non-driving side.

  The image forming apparatus 100 is mounted on a substantially horizontal installation surface F such as a mounting table, desk, or floor. An image forming unit 200 is disposed in the center of the apparatus main body 100A. FIG. 2 is an enlarged view of the image forming unit 200 portion in FIG. The unit 200 has a single cartridge mounting portion (mounting guide) 32l for detachably mounting a plurality of cartridges, in the present embodiment, the first to fourth developing cartridges 33 (33Y, 33M, 33C, and 33K). Intermediate transfer member (transfer member) 34. In this embodiment, the electrophotographic photosensitive drum 32a corresponding to each developing cartridge 33 is attached to the unit 200 as a photosensitive unit 32 (32Y, 32M, 32C, 32K) together with a charging roller 32b and a cleaning blade 32c. . The charging roller 32b and the cleaning blade 32c are process means. The image forming apparatus 100 forms a color image on the recording medium S by detachably attaching a plurality of cartridges 33 to the apparatus main body 100A (unit 200). A more detailed configuration of the unit 200 will be described later. In the present embodiment, the developing cartridges 33 have the same configuration except that the color of the stored developer (toner) is different. However, it is not limited to this. For example, the developer cartridge 33K that stores a black developer may have a larger capacity of the developer storage portion 33c than the developer cartridge 33 that stores a developer of another color. In this embodiment, a developing cartridge will be described as an example of the cartridge, but the present invention is not limited to this. For example, in this embodiment, the drum 32a, the charging roller 32b, and the cleaning blade 32c attached to the unit 200 may be attached to the developing cartridge 33. In such a configuration, the cartridge is referred to as a process cartridge rather than a developing cartridge. This is because the drum 32a, the charging roller 32b as the process means, the developing roller 33b, and the cleaning blade 32c are integrally formed as a cartridge and detachably attached to the apparatus main body 100A.

(Photoreceptor unit)
Each unit 32 (32Y, 32M, 32C, 32K) is fixed to the subframe 31 of the image forming unit 200. Each unit 32 has a drum 32a. In addition, a charging roller 32b and a cleaning blade 32c for removing the developer remaining on the surface of the drum 32a are provided as process means acting on the drum 32a. In addition, a transport screw (transport member) 32e that transports the developer removed by the cleaning blade 32c in the axial direction of the drum 32a is provided. The drum 32a, the charging roller 32b, the cleaning blade 32c, and the conveying screw 32e are assembled to the case 32d in a predetermined arrangement relationship.

  (A) of FIG. 3 is the perspective view which looked at the unit 32M from the left side. (B) is a perspective view of the photoconductor case 32d in which the drum 32a, the charging roller 32b, and the cleaning blade 32c are removed from the unit 32M of (a). 4A is a perspective view of the case 32d of FIG. 3B viewed from the right side, and FIG. 4B is an enlarged vertical sectional view of the removed developer discharge portion 32f of the case 32d. Since the other units 32Y, 32C, and 32K have substantially the same configuration, the unit 32M will be described as an example in the description of the photosensitive unit 32. Bearing portions 32d1 and 32d2 each having a through hole are provided on the right end side and the left end side of the case 32d, respectively, and rotatably support the drum 32a. Further, inside the bearing portions 32d1 and 32d2, end seal members 32k1 and 32k2 that are in contact with the drum 32a and a sheet-like seal member 32h that extends in the axial direction of the drum 32a are provided. Each of the sealing members 32k1, 32k2, and 32h is in contact with the surface of the drum 32a to prevent the developer in the case 32d from leaking out. Inside the case 32d, a conveying screw 32e is provided in the longitudinal direction. A conveying gear 32i is provided on the right end side of the screw 32e, and receives a driving force from a drum gear 32a1 provided on the right end side of the drum 32a via an idler gear 32j. The screw 32e is configured to convey the removed developer in the case 32d in the direction of arrow X7 (left direction) by its rotational operation. The removed developer conveyed by the screw 32e is carried to the removed developer discharge portion 32f on the left end side of the screw 32e. The discharge portion 32f has a shape protruding outward from the left end side of the case 32d. The removed developer conveyed by the screw 32e is discharged to the outside through an opening 32g1 provided in the discharge portion 32f. The opening 32g1 is provided with a rotatable shutter 32g. The shutter 32g is rotated to move between an open position where the opening 32g1 is opened and a closed position where the opening 32g1 is closed. The shutter 32g is moved to the open position by the mounting operation of the waste developer container 40 (FIGS. 12 and 13) described later with respect to the unit 200. As a result, the removed developer in the case 32d can be discharged into the container 40. When the container 40 is not attached, the shutter 32g is biased to the closed position by a spring (not shown), so that the developer does not leak outside.

  On the right end side and the left end side of each unit 32, there is a mounting portion 32l for mounting the cartridge 33 extending in a direction orthogonal to the axis of the drum 32a. A part of the mounting portion 32l is provided with a recessed portion 32la for receiving the guided portions (restricted portions) 33e1 and 33e3 (FIG. 5) of the cartridge 33. Further, a regulating member 36 that regulates the position of the cartridge 33 and a biasing member 37 that biases the regulating member 36 are provided adjacent to the recess 32la.

  As described above, since each unit 32 is provided with the conveying screw 32e that conveys the removed developer to the outside, a space for accommodating the removed developer is not required inside, so that the unit 32 can be reduced in size. In the present embodiment, the example in which the unit 32 is fixed to the unit 200 has been described. Accordingly, when the drum 32a or the like is consumed, the unit 200 is replaced. However, the unit 32 may be configured to be detachable from the unit 200 so that only the unit 32 can be replaced.

(cartridge)
As shown in FIG. 2, each cartridge 33 (33Y, 33M, 33C, 33K) supplies developer to the case 33a and the drum 32a, that is, the electrostatic latent image formed on the drum 32a is used as the developer image. A developing roller 33b is provided for development. The cartridge 33 also includes a developer accommodating portion 33c that accommodates a developer used for developing the electrostatic latent image, and a supply roller 33d that supplies the developer in the developer accommodating portion 33c to the developing roller 33b. The developer accommodating portion 33c is provided with a conveying member 33f for conveying the internal developer to the supply roller 33d. The first cartridge 33Y stores a yellow (Y) developer in the developer storage portion 33c, and forms a Y developer image on the surface of the corresponding drum 32a. The second cartridge 33M stores a magenta (M) color developer in the developer storage portion 33c, and forms an M color developer image on the surface of the corresponding drum 32a. The third cartridge 33C stores cyan (C) color developer in the developer storage portion 33c, and forms a C color developer image on the surface of the corresponding drum 32a. The fourth cartridge 33K stores a black (K) developer in the developer storage portion 33c, and forms a K color developer image on the surface of the corresponding drum 32a.

  5A is a perspective view of the cartridge 33Y viewed from the right side, and FIG. 5B is a perspective view of the cartridge 33Y viewed from the left side. Each cartridge 33 will be described by taking this cartridge 33Y as an example. The cartridge 33Y is mounted in the direction of the arrow X10 with respect to the mounting portion 32l of the unit 200. Further, the cartridge 33Y is detached from the mounting portion 32l of the unit 200 in the direction of the arrow X11 opposite to the arrow X10. The cartridge 33Y has a developing roller 33b on the tip side in the mounting direction. A gear 50 is provided on the right end side of the developing roller 33b, and receives the driving force from the drum gear 32a1 to rotate the developing roller 33b. The gear 50 further transmits drive to the supply roller 33d and the conveyance member 33e via a gear train (not shown). On the right end side and the left end side of the cartridge 33Y, guided portions 33e1, 33e2, 33e3, 33e4 are provided for guiding the cartridge 33Y when the cartridge 33Y is mounted on the unit 200, respectively. The guided portions 33e1 and 33e3 each have a cylindrical shape, and protrude to the outside on the right end side and the outside on the left end side of the cartridge 33Y. Each of the guided portions 33e2 and 33e4 has a substantially rectangular parallelepiped shape, protrudes to the outside on the right end side and the outside on the left end side of the cartridge 33Y, and extends in a direction orthogonal to the longitudinal direction of the cartridge 33. The guided portions 33e1 and 33e3 are located downstream of the guided portions 33e2 and 33e4 in the mounting direction X10 of the cartridge 33Y. Further, on the opposite side to the developing roller 33b side of the cartridge 33Y, a first grip portion 39 (see FIG. 2) for gripping the cartridge 33Y, in which the bottom plate of the case 33a is recessed, is provided. A second grip 38 for gripping the cartridge 33Y is provided above the cartridge 33Y. The user can attach / detach the cartridge 33 </ b> Y to / from the unit 200 by gripping the flat portion 38 a of the first grip portion 39 and the second grip portion 38. Further, the user can attach and detach the cartridge 33Y to and from the unit 200 by holding the second grip portion 38. As described above, the cartridge 33 </ b> Y has the first grip portion 39 and the second grip portion 38. Further, the other cartridges PM, PC, and PK have only the first gripping portion 39. Other cartridges PM, PC, and PK can be attached to and detached from the unit 200 by holding the first holding portion 39 and the upper surface portion of the case 33a.

  In the present embodiment, the intermediate transfer member 34 is a cylindrical drum disposed horizontally so that the axis of the rotation center 34a is in the left-right direction and is rotatable about the axis. The cartridges 33 are arranged on the front surface side of the intermediate transfer body 34 in a substantially horizontal posture with respect to the installation surface F of the apparatus main body 100A, and adjacently arranged in the vertical direction from top to bottom. In the image forming apparatus of the present embodiment, the first cartridge 33Y is the uppermost stage, and the second cartridge 33M is positioned therebelow. The third cartridge 33C is located further below. The fourth cartridge 33K is the lowest stage. The developing roller 33b of each cartridge 33 may be in contact with the drum 32a as a contact developing method, or has a predetermined small gap (a constant distance) with respect to the drum 32a as a non-contact developing method. May be separated.

(Scanner unit)
Referring to FIG. 1, a laser scanner unit 11 as an image exposure device is disposed on the front side (front portion) of each cartridge 33. This unit 11 is disposed in the apparatus main body 100A between the front frame 110a of the main frame 110 serving as a skeleton of the apparatus main body and each cartridge 33. The unit 11 includes a laser diode, a polygon mirror, an Fθ lens, a reflection mirror, and the like. The unit 11 outputs a laser beam L (LY, LM, LC, LK) modulated in accordance with image information of each color of Y, M, C, K input from the external host device 400 to the control circuit unit 300. Then, the drum 32a in the corresponding color cartridge 33 is scanned and exposed.

(Recording medium transport mechanism)
A feeding unit 18 is disposed below the image forming unit 200. The feeding unit 18 includes a feeding cassette 19 on which the recording medium S is stacked and stored, a feeding roller 20, a separation pad 21, and the like. The feeding cassette 19 can be taken in and out (inserted / removed) freely from the front side of the apparatus main body 100A (front loading). Further, in the apparatus main body 100A, a recording medium conveyance path Z extending from the feeding roller 20 to the upper rear side in the apparatus main body 100A is provided between the intermediate transfer member 34 and the rear frame 110b of the apparatus main body 100A. It is arranged. A registration roller pair 18a, a secondary transfer roller 22, a fixing device 23, and a discharge roller pair 24 are arranged along the transport path Z from the bottom to the top. The fixing device 23 has a fixing film unit 23a and a pressure roller 23b. The discharge roller pair 24 is a discharge roller 24a and a discharge roller 24b. A maintenance cover 10 that also serves as a discharge tray that receives the recording medium S on which an image has been formed is disposed on the upper surface of the apparatus main body 100A. The cover 10 is an opening / closing member capable of opening and closing an opening 100B provided on the upper surface of the apparatus main body 100A. As will be described later, the opening 100B is an opening for attaching and detaching the cartridge 33 to and from the unit 200 positioned at the attachment / detachment position B (FIGS. 10B and 14) where the cartridge can be attached to and detached from the apparatus main body. It is.

  FIG. 1B shows a state in which the image forming apparatus 100 can perform an image forming operation. In this state, the cover 10 is closed at the closing position G that closes the opening 100B. The unit 200 is mounted with each cartridge 33 and is located at an image forming position A where image formation is performed on the apparatus main body. A drive output portion (not shown) provided on the apparatus main body 100A side is connected to a gear 34b (FIG. 6) which is a drive input portion of the intermediate transfer member 34 of the unit 200. In addition, a power supply system (not shown) provided on the apparatus main body 100 </ b> A side is electrically connected to an electrical contact (not shown) between each unit 32 and the cartridge 33. Here, the drive system and the bias application system described above are omitted in the drawing for the sake of simplicity, but the same configuration as that of a normal image forming apparatus can be employed.

  The operation for forming a full-color image is as follows. Referring to FIGS. 1B and 2, each drum 32a is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined speed. The charging roller 32b rotates following the rotation of the drum 32a. The intermediate transfer member 34 is also driven to rotate in the clockwise direction indicated by the arrow (forward direction with respect to the rotation of the drum 32a) at a speed corresponding to the speed of the drum 32a. Further, the developing roller 33b and the supply roller 33d are each driven to rotate in the clockwise direction indicated by the arrows at a predetermined speed. The scanner unit 11 is also driven. In synchronization with this drive, a predetermined charging bias is applied to each charging roller 32b at a predetermined control timing. As a result, the surface of each drum 32a is uniformly charged to a predetermined polarity and potential by the charging roller 32b. The scanner unit 11 scans and exposes the surface of each drum 32a with laser light L (LY, LM, LC, LK) modulated according to the corresponding image signals of Y, M, C, and K. Thereby, an electrostatic latent image corresponding to the image signal of the corresponding color is formed on the surface of the drum 32a of each cartridge P. Then, the electrostatic latent image formed on the surface of each drum 32 a is developed as a developer image by the developing roller 33 b of the corresponding cartridge 33. A predetermined developing bias is applied to each developing roller 33b at a predetermined control timing. By the electrophotographic image forming process operation as described above, a Y color developer image corresponding to the Y color component of the full color image is formed on the drum 32a facing the cartridge 33Y. Then, the developer image is primarily transferred onto the intermediate transfer member 34 at a primary transfer nip portion that is a contact portion between the drum 32 a and the intermediate transfer member 34. An M color developer image corresponding to the M color component of the full color image is formed on the drum 32a facing the cartridge 33M. Then, the developer image is superimposed on the Y color developer image already transferred onto the intermediate transfer member 34 at the primary transfer nip portion where the drum 32a and the intermediate transfer member 34 are in contact with each other. Is done. A C-color developer image corresponding to the C-color component of the full-color image is formed on the drum 32a facing the cartridge 33C. The developer image is superimposed on the Y + M color developer image that has already been transferred onto the intermediate transfer member 34 in the primary transfer nip portion where the drum 32a and the intermediate transfer member 34 are in contact with each other. Primary transcription. A K color developer image corresponding to the K color component of the full-color image is formed on the drum 32a facing the cartridge 33K. Then, the developer image is superimposed on the Y color + M color + C color developer image already transferred onto the intermediate transfer member 34 in the primary transfer nip portion where the drum 32a and the intermediate transfer member 34 are in contact with each other. The primary transfer is done. In this way, a full-color unfixed developer image of Y color + M color + C color + K color is synthesized and formed on the intermediate transfer member 34. Note that the color order of the developer images sequentially superimposed and transferred onto the intermediate transfer member 34 is not limited to the above order. The residual transfer developer remaining on the drum surface after the primary transfer of the developer image to the intermediate transfer member 34 in each drum 32a is removed by the cleaning blade 32c, and the waste developer container 40 (see FIG. 13) is conveyed via the conveying screw 32e. (B)).

  On the other hand, the feeding roller 20 is driven at a predetermined control timing. As a result, the sheet-like recording medium S stacked and stored in the feeding cassette 19 is separated and fed one by one in cooperation with the feeding roller 20 and the separation pad 21. Then, the recording medium S is introduced into the secondary transfer nip portion which is a contact portion between the intermediate transfer body 34 and the secondary transfer roller 22 at a predetermined control timing by the registration roller pair 18a. A secondary transfer bias having a polarity opposite to the charging polarity of the developer is applied to the secondary transfer roller 22 at a predetermined control timing. Thus, the four-color superimposed developer image on the intermediate transfer member 34 is secondarily transferred onto the surface of the recording medium S in order while the recording medium S is nipped and conveyed through the secondary transfer nip portion. The recording medium S that has passed through the secondary transfer nip is separated from the surface of the intermediate transfer member 34 and introduced into the fixing device 23 where it is heated and pressurized at the fixing nip. Thereby, the color mixing of the developer images of the respective colors and the fixing to the recording medium S are performed. Then, the recording medium S exits the fixing device 23 and is discharged onto the cover 10 serving also as a discharge tray by the discharge roller pair 24 as a full-color image formed product. The secondary transfer residual toner remaining on the surface of the intermediate transfer member 34 after the separation of the recording medium S from the intermediate transfer member 34 is removed. In the case of the present embodiment, it adheres electrostatically to the surface of the drum 32a at the primary transfer nip portion between the drum 32a of the unit 32Y and the intermediate transfer member 34, and is removed by the cleaning blade 32c.

  The intermediate transfer body 34 is a drum-shaped rotating body. On the intermediate transfer member 34, developer images of different colors formed on the respective drums 32a are transferred in a superimposed manner. Then, the intermediate transfer member 34 collectively transfers the developer images transferred in a superimposed manner onto the recording medium S. As a result, a color image is formed on the recording medium S. In the case of forming a monochrome image, the K developer image formed on the drum 32a facing the cartridge 33K is transferred to the intermediate transfer member 34. Then, the intermediate transfer member 34 transfers the transferred K color developer image to the recording medium S. A K color image is formed on the recording medium S. In this embodiment, the secondary transfer roller 22 is brought into contact with the intermediate transfer body 34 by a shift mechanism (not shown) to form a secondary transfer nip portion, and is not in contact with the intermediate transfer body 34. It is possible to move to a second position apart. The secondary transfer roller 22 is moved to the first position during the image forming operation of the image forming apparatus 100, and is moved to the second position during non-image formation. A configuration in which the secondary transfer roller 22 is always in contact with the intermediate transfer member 34 can also be adopted.

<Image forming unit>
The configuration of the unit 200 will be described with reference to FIG. (A) is the perspective view which looked at the unit 200 from the left side, (b) is the perspective view which looked at the right side. The unit 200 includes a subframe 31 that can be attached to and detached from the main frame 110 of the apparatus main body 100A. The subframe 31 rotatably supports an intermediate transfer member 34 whose peripheral surface is covered with an elastic body. The intermediate transfer member 34 is supported between a left side plate 31L and a right side plate 31R of the subframe 31 so that a left end portion and a right end portion of a center axis (rotation center) 34a are rotatably supported. On the outer surface side of the left side plate 31L and the right side plate 31R, a left shaft portion 45L and a right shaft portion 45R are integrally fixed to the side plates 31L and 31R, coaxially with the central shaft 34a of the intermediate transfer member 34, respectively. It is installed. A gear 34b that transmits a driving force to each drum 32a is provided on the right end side of the intermediate transfer member 34, and the driving force transmitted from an apparatus main body drive source (not shown) is transmitted to the drum gear 32a1. Around the intermediate transfer member 34, the above-described photoreceptor units 32 (32Y, 32M, 32C, and 32K) are arranged in a state where the drums 32a are in contact with the intermediate transfer member 34. Each of the units 32 is positioned with respect to the subframe 31 by a positioning configuration (not shown) and fixed by screws or the like. Accordingly, the drum 32a and the intermediate transfer member 34 of each unit 32 can be positioned with high accuracy. Each drum 32a is in contact with the intermediate transfer member 34 with a predetermined pressing force. Each unit 32 is inserted and fixed to the subframe 31 from the direction of the arrow X1. At this time, the removed developer discharge portion 32f provided on the left end side of each unit 32 is inserted into the subframe 31 through the corresponding opening 31k provided on the left side plate 31L of the subframe 31. The removed developer discharge portion 32f is installed on the subframe 31 so as to protrude outward from the left side plate 31L. By providing the opening 31k, even the removed developer discharge portion 32f protruding in the axial direction of the drum 32a can be attached in a direction orthogonal to the axial line of the drum 32a. The right side plate 31R of the subframe 31 is provided with a regulated portion 31l that regulates the rotation of the unit 200 within the apparatus main body 100A. The unit 200 is positioned in the apparatus main body 100A by the left shaft portion 45L, the right shaft portion 45R, and the regulated portion 31l. Details will be described later. By providing the left shaft portion 45L and the right shaft portion 45R, which are positioning portions of the intermediate transfer body 34 in the apparatus main body 100A, and the rotation restricted portion 31l in the subframe 31 which is the same member, the intermediate transfer body. The position of 34 in the apparatus main body 100A is determined with high accuracy. In order to rotate the unit 200 by a predetermined angle, a grip portion 31 m is provided on the upper portion of the subframe 31. The user grasps the grasping portion 31m, so that the unit 200 is moved to the image forming position A (FIG. 1B, FIG. 2) for image formation and the attachment / detachment position B (FIG. 10) for attaching / detaching the cartridge 33. (B) and FIG. 14). In addition, a part of the right side plate 31R of the subframe 31 is provided with a rotation restricted portion 31n for restricting the rotation position of the unit 200 when the unit 200 is rotated by a predetermined angle. The regulated portion 31n is engaged with a later-described regulating portion 46 (FIGS. 7 and 8) on the apparatus main body 100A side to regulate the position. The regulated portion 31n is a through hole having a triangular cross section. A guide portion 31o for guiding the rotation restricting portion 46 is provided on the right side plate 31R reaching the restricted portion 31n, and guides the restricting portion 46 to the restricted portion 31n. The top plate 31C connecting the left side plate 31L and the right side plate 31R of the subframe 31 is pressed by a unit biasing spring 35 described later provided on the cover 10 to position the unit 200 in the apparatus main body 100A. The pressed part 31p is provided. As described above, each photoconductor unit 32 fixed to the sub-frame 31 is provided with the cartridge mounting portion 32l for detachably mounting the cartridge 33. The mounting portion 32l of the cartridge 33Y is divided into a first mounting portion (mounting guide) 32l1 and a second mounting portion (mounting guide) 32l2. The mounting portions 32l1 and 32l2 include a mounting portion 32l of the unit 32Y, a left side plate 31L, and a right side plate 31R. The function of each mounting part will be described later.

(Image forming unit mounting part)
As shown in FIG. 7, a left guide plate 80L and a right guide plate 80R are fixedly disposed inside the left frame 110L and the right frame 110R of the apparatus main body 100A so as to face each other. The guide plates 80L and 80R respectively include a positioning portion 80a that rotatably supports the left and right shaft portions 45L and 45R of the subframe 31, and a guide portion 80b that guides the shaft portions 45L and 45R to the positioning portion 80a. It has. The right guide plate 80R is provided with a rotation restricting portion 80c continuous with the guide portion 80b. The rotation restricted portion 31l provided in the unit 200 is in contact with the right guide plate 80R to restrict the rotation of the unit 200. On the upper side of the right guide plate 80R, a restricting portion 46 that restricts the rotational angle position of the unit 200 via the restricted portion 31n of the unit 200 is provided so as to freely advance and retract. As shown in FIG. 8A, the tip of the restricting portion 46 has a tapered surface 46a. The restricting portion 46 is biased by the biasing member 47 in the direction of the arrow Y0 toward the inside of the apparatus main body 100A. The restriction portion 46 is provided with a flange portion 46b to prevent the restriction portion 46 from falling off the guide plate 80R.

(Installation of image forming unit)
Next, mounting of the unit 200 in the apparatus main body 100A will be described. The back side of the cover 10 is rotatably connected to the apparatus main body 100A via a hinge shaft 10a, and a closing position G (FIG. 1 (b)) for closing the opening 100B on the upper surface of the apparatus main body 100A. And an open position H (FIG. 7) for opening the opening 100B. That is, the cover 10 is an opening / closing member that can be opened / closed and rotated around the hinge shaft 10a above the apparatus main body 100A to open / close the opening 100B. As shown in FIG. 9A, the cover 10 is closed on the side of the maintenance button 36 disposed on the front surface of the apparatus main body 100A and on the cover 10 side. It is maintained by engagement (latching engagement) with the provided locking claw portion 10b. The locking claw portion 36a is a main body side locking portion, and the locking claw portion 10b is an opening / closing member side locking portion. The cover 10 is released by pressing the button 36. When the button 36 is pushed backward against a return spring (not shown), the latching claw 36a on the button 36 side escapes rearward from the latching claw 10b of the cover 10 as indicated by a two-dot chain line, and latches. Mismatch. Thereby, the cover 10 can be rotated to the open position H around the hinge shaft 10a, so that the opening 100B can be largely opened. In the present embodiment, the locking claw portion 36a and the locking claw portion 10b are elastically and releasably locked. However, the present embodiment is not limited to this. For example, a claw (locking portion) provided on the other side may be elastically and releasably locked on a hole (locking portion) provided on one side.

  As shown in FIG. 10A, when the unit 200 is mounted in the apparatus main body 100A, the cover 10 is rotated to the open position H to largely open the opening 100B. Then, the unit 200 is inserted into the apparatus main body 100A from the opening 100B. The unit 200 is inserted into the apparatus main body 100A by engaging the left and right shaft sections 45L and 45R with the guide sections 80b provided facing the left and right guide plates 80L and 80R on the apparatus main body 100A side. Installed. Thereafter, the shaft portions 45L and 45R are brought into contact with the positioning portion 80a provided on the extension line of the guide portion 80b ((b) in FIG. 10). At this time, a gear 34b (FIG. 6) provided on one end side of the intermediate transfer member 34 is connected to a drive gear (not shown) provided in the apparatus main body 100A. Thereafter, the unit 200 is rotated in the direction of the arrow X2 shown in FIG. A spring member 48 is provided on the upper surface of the lower stay 110c of the main frame 110 below the arrow X2 in the apparatus main body 100A. The spring member 48 has a function of abutting against the lower surface of the subframe 31 of the unit 200 when the unit 200 is rotated, and mitigating an impact caused by the rotation operation of the unit 200. The unit 200 rotated in the direction of the arrow X2 stops the rotation operation while being urged upward by the spring member 48. Thereafter, the cover 10 is rotated to the closed position G, and the mounting of the unit 200 in the apparatus main body 100A is completed. The unit 200 is disposed between the left and right guide plates 80L and 80R in the apparatus main body 100A so as to be rotatable around the shaft portions 45L and 45R, that is, the rotation center 34a of the intermediate transfer body 34. As a result, the unit 200 takes the image forming position A (FIG. 1 (a), FIG. 2) for image formation and the attachment / detachment position B (FIG. 10 (b)) for attaching / detaching the cartridge 33. obtain. This will be described later.

(Waste developer container)
11B is a right perspective view of the waste developer container 40, FIG. 12A is a left perspective view, and FIG. 11B is a cross-sectional view taken along the section line (12)-(12) in FIG. FIG. As described above, in each photosensitive unit 32 (32Y, 32M, 32C, and 32K), the developer remaining on the surface of the drum 32a is removed by the cleaning blade (cleaning member) 32c, and then the conveying screw (conveying member). 32e is transported in the transport direction. The conveyed waste developer is accommodated in a container 40 that is detachably provided on the left end side of the unit 200 that is downstream in the conveying direction of the conveying screw 32e. The container 40 is obtained by integrating a storage container 41 and a lid 42 by welding or the like. The storage container 41 is provided with a waste developer receiving opening 41 a corresponding to each unit 32. Each opening 41 a is located in a recess 41 b provided in the storage container 41, and the recess 41 b has a size that allows passage of the removed developer discharge portion 32 f of the unit 32. Around each opening 41b, there is provided a seal member 43 that contacts the removed developer discharge portion 32f and prevents the developer from scattering to the outside. The seal member 43 is fixed to the storage container 41 with a double-sided tape or the like. The seal member 43 is provided with an opening having substantially the same size as the opening 41a. A storage portion 41c is formed below the opening 41a to store the waste developer received through the opening 41a. Guided portions 41 d to 41 f for mounting the container 40 to the unit 200 are provided on the right side of the storage container 41. The container 40 is mounted and positioned on the unit 200 via the guided portions 41d to 41f. The lid 42 is provided with a gripping portion 42 a for attaching and detaching the container 40 to and from the unit 200. The gripping portion 42a is configured to have a recess in the lid 42. When a predetermined amount or more of the waste developer is stored in the container 40, the user grasps the grasping portion 42a and removes it from the unit 200, and replaces it with a new container 40. Alternatively, it is possible to discard the waste developer in the container 40 and use it again.

(Installation of waste developer container in image forming unit)
The container 40 is attached / detached in a state where the unit 200 is located at the attachment / detachment position B (FIG. 10 (b)). Guide portions 31m1 to 31m3 are provided on the outer surface of the left side plate 31L of the subframe 31 as shown in FIG. 6 (a) and FIG. 13 (a). The guided portions 41d to 41f provided in the container 40 are inserted into the guide portions 31m1 to 31m3 in the direction of the arrow X3. A leaf spring-like biasing member 49 is provided in the guide portion 31m2, and after receiving the guided portion 41e, the guided portion 41e is biased in the direction of the arrow X4. The guided portion 41e is urged by the urging member 49 so that the positioned portion 41e1 ((b) of FIG. 11) is brought into contact with the positioning portion 31m4 provided at the rear end of the guide portion 31m2. Position in the front-rear direction. Further, since the vertical width of the guided portion 41e is substantially the same as the vertical width of the guide portion 31m2, the vertical positioning is also performed at the same time. Furthermore, since the urging member 49 restricts the movement in the direction opposite to the direction of the arrow X3, the unit 200 does not come out of the unit during the turning operation. As described above, the container 40 is attached to and detached from the unit 200 (FIG. 13B). By this series of mounting operations, the container 40 moves the shutter 32g provided in each unit 32 to the open position by an actuator (not shown). When the mounting is completed, the opening 41a provided in the container 40 faces the opening 32g1 provided in the unit 32, and it becomes possible to receive the waste developer conveyed by the conveying screw 32e.

When replacing the container 40, as described above, the grip portion 42a is gripped and removed from the unit 200. With the unit 200 positioned at the attachment / detachment position B, the container 40 can also be exchanged at the same position as the attachment / detachment position B of the cartridge 33 described later. In accordance with the operation of removing the container 40, the opening of the unit 32 is closed by the movement of the shutter 32g by the spring member. On the other hand, the opening 41a of the container 40 is not provided with a member such as a shutter in order to reduce costs. However, since the opening 41a does not face downward in the direction of gravity in the attaching / detaching direction of the container 40 (X3 direction in FIG. 13A and the opposite direction), the internal waste is not provided without providing a shutter or the like. It is possible to suppress the leakage of the developer to the outside as much as possible. Since the container 40 can be attached to and detached from the unit 200, the user can replace the cartridge 33 and replace the container 40 by the same method, which is excellent in usability. Moreover, since the attachment / detachment direction of the container 40 and the attachment / detachment direction of the cartridge 33 to be described later are set in the same direction, the user can easily perform both operations. Here, the same direction means that the container 40 and the cartridge 33 may be attached and detached without changing the position of the unit 200, and the directions may be slightly shifted. The guide portions 31 m 1 to 31 m 3 of the unit 200 to which the container 40 is attached are provided on the outer surface of the subframe 31. Accordingly, there is no need to provide a storage space for storing the container 40 in the subframe 31, and the apparatus can be reduced in size. The attachment position of the container 40 is provided in the axial direction of the drum 32a on the non-drive side opposite to the drive side on which drive systems (drive transmission units) such as the drum gear 32a1 and the transport gear 32f are provided. Therefore, it is possible to give a degree of freedom to the arrangement of the drive system, and as a result, it is possible to reduce the size of the apparatus.

(Installation of cartridge)
The cartridges 33 (33Y, 33M, 33C, and 33K) are attached to and detached from the unit 200 in a state where the unit 200 is positioned at the attachment / detachment position B ((b) of FIG. 10). First, the cover 10 is moved from the closed position where the opening 100B is closed to the open position where the opening 100B is opened ((a) of FIG. 11). Next, the holding part 31m provided in the unit 200 is held and the unit 200 is rotated to the attachment / detachment position B ((b) of FIG. 10). When the rotation operation is performed at a predetermined angle, the restricting portion 46 provided in the apparatus main body 100A engages with the restricted portion 31n provided in the subframe 31. At this time, the position of the unit 200 is regulated by the regulating unit 46 at the attachment / detachment position B. That is, the unit 200 is temporarily fixed at the attachment / detachment position B and is restricted from moving in the direction of the image forming position A. Since the unit 200 is restricted to the attachment / detachment position B, the user can perform the attachment / detachment work of the cartridge 33 in a state where the grip portion 31m is released, so that the usability is good.

  First, a first grip 39 (FIG. 2) provided in the cartridge 33 (33M, 33C, 33K) and a part of the developer case 33a are gripped. With respect to the cartridge 33Y, the flat surface portion 38a (FIG. 5) of the first grip portion 39 and the second grip portion 38 is gripped. Alternatively, only the second grip 38 is gripped. Then, each cartridge 33 is mounted on the corresponding mounting portion 32 l of the unit 200. The mounting direction is mounted from a direction (mounting direction) orthogonal to the rotation axis of the developing roller 32b. That is, as shown in FIGS. 14A and 18A, the guided portions 33e1 and 33e3 on the cartridge 33 side are inserted into the mounting portion 32l on the unit 200 side. FIGS. 14A and 18A show the case where the cartridge 33Y is mounted. When the cartridge 33Y is mounted, it is inserted into the first mounting portion 32l1. Subsequently, the guided portions 33e2 and 33e4 are inserted. The guided portions 33e1 to 33e4 are guided by the mounting portion 32l and are inserted into the interior toward the drum 32a. The guided portions 33e1 and 33e3 are in contact with the regulating member 36 provided in the mounting portion 32l. In this embodiment, the regulating member 36 is a chevron-shaped member, and the guided portions 33e1 and 33e3 abut on the chevron-shaped portion. In the free state, the restricting member 36 is pushed up by the urging force of the urging member 37 so that the chevron-shaped portion enters the recess 32la of the mounting portion 32l and the upper surface abuts against the ceiling surface of the recess 32la and is received. Yes. The pushing position of the regulating member 36 at this time is defined as a regulating position D. When the cartridge 33 is further inserted, the guided portions 33e1 and 33e3 act to push down against the urging force of the urging member 37 urging the regulating member 36 with the angled portion of the regulating member 36 as the cam inclined surface. To do. As a result, the restricting member 36 is pushed down in the direction of the arrow X5 retracted from the recess 32la of the mounting portion 32l, and the guided portions 33e1 and 33e3 enter between the upper surface of the restricting member 36 and the ceiling surface of the recess 32la. ((B) of FIG. 18). At this time, the pressing position of the restricting member 36 is set as an allowable position E, and the cartridge 33 is allowed to be attached and detached. As a result, the guided portions 33e1 and 33e3 enter the inner side of the recess 32la beyond the restricting member 36. The guided portions 33e2 and 33e4 also enter the recess 32la of the mounting portion 32l ((c) in FIG. 18). Thereby, the mounting of the cartridge 33 into the unit 200 is completed. When the guided portions 33e1 and 33e3 pass, the restricting member 36 moves again in the direction of the arrow X6, which is opposite to the direction of the arrow X5, and returns to the original restricting position D by the urging force of the urging member 37. The user pushes down the restricting member 36 against the urging force of the urging member 37, and the restricting member 36 returns to the original restricting position D to release the urging force, thereby obtaining an appropriate cartridge mounting feeling. Can do. In this state, the guided portions 33e1 and 33e3 are in a state where movement of the guided portions 33e1 and 33e3 to the upstream side in the mounting direction is restricted by the restriction member 36. Therefore, even if the cartridge 33 moves to move upstream in the mounting direction, the movement is restricted by the restriction member 36 and does not fall out of the unit 200. The position of the restricting member 36 when the restricting member 36 allows the mounting of the cartridge 33 is defined as an allowable position E (position where the restricting member 36 is pushed down in the arrow X5 direction), and the position when restricting the movement of the cartridge 33 is restricted. The position is D (the position shown in FIG. 14A). The cartridge 33 is mounted on the unit 200 in a state where the guided portions 33e1 and 33e3 are movable in the recess 32la. The user needs only to install the cartridge 33 in the unit 200 roughly. That is, since the cartridge 33 does not have to be positioned with respect to the unit 200 at the attachment / detachment position B, the mounting operation is simple. In the present embodiment, an example in which the regulating member 36 is provided in the unit 200 is shown. However, a regulating member may be provided outside the unit 200. That is, as long as the cartridge 33 can be prevented from dropping out of the unit 200, the regulating member 36 may be provided anywhere.

(Moving the image forming unit to the image forming position)
As shown in FIG. 14B, when the mounting of each cartridge 33 to the unit 200 is completed, the user rotates the unit 200 in the direction of the image forming position A. First, the second holding portion 38 of the cartridge 33Y provided at the uppermost stage of the unit 200 is held, or the holding portion 31m provided on the subframe 31 of the unit 200 is held, and the unit 200 is moved in the direction of the arrow X8. Apply power. In the unit 200 to which the force is applied, the restricting portion 46 that restricts the position (attachment / detachment position) B is detached from the restricted portion 31n, and becomes rotatable. As shown in FIG. 8B, the restricting portion 46 and the restricted portion 31n form a surface inclined with respect to the arrow X8 that is the rotation direction of the unit 200. Then, as shown in FIG. 8C, the unit 200 is rotated by the restricted portion 31n retracting the restricting portion 46 in the arrow Y1 direction by the turning operation in the arrow X8 direction. By setting the urging member 47 that urges the regulating member 46 in the direction of the arrow Y0 to a certain or greater urging force, the regulated portion 31n is regulated in the attachment / detachment operation of the cartridge 33 at the attachment / detachment position B of the unit 200. Do not come off part 46. On the other hand, it is preferable to set the biasing force so that the restriction is released in the turning operation by the user. The unit 200 rotates around the left shaft portion 45L and the right shaft portion 45R while being supported by the positioning portion 80a.

  The unit 200 moves in the direction of the arrow X8 when the user holds the second grip 38 or the grip 31m. The user may hold either the second holding part 38 or the holding part 31m. In the present embodiment, since the second grip 38 provided on the cartridge 33Y is on the outside of the unit 200, it is easy to grip and recognize. That is, the second gripping portion 38 is located outside the gripping portion 31m in the radial direction of the unit 200. The second grip 38 has a recess 38b through which a user can insert a hand. Since the recess 38b is opened outward in the radial direction of the unit 200, it is easy to operate when moving the unit 200. The second grip 38 is a part that grips the unit 200 so as to rotate from the attachment / detachment position B to the front / removal position C in FIG. 15A or from the attachment / detachment position B to the image forming position A. In addition, the unit 200 is also a part for gripping the unit 200 at the front / rear position C or the image forming position A to rotate to the attachment / detachment position B. The second grip 38 is provided on the most downstream side in the rotation direction (the direction of the arrow X9) from the image forming position A to the attaching / detaching position B among the plurality of cartridges 33 (33Y, 33M, 33C, 33K). The cartridge 33Y is provided. If the cartridge 33Y is not mounted, it is preferable to grip the grip portion 31m provided on the subframe 31.

  When the user operates the unit 200 while holding the second holding portion 38, the movement of the guided portions (restricted portions) 33e1 and 33e3 is restricted by the restriction member 36 located at the restriction position D. . Accordingly, when the unit 200 is moved while gripping the second gripping portion 38, even if a force with which the cartridge 33Y is pulled out of the unit 200 is applied to the cartridge 33Y, it is restricted by the restriction member 36 and falls out of the unit 200. There is nothing to do. That is, the regulating member 36 prevents the cartridge 33Y from dropping out when the unit 200 is rotated from the attaching / detaching position B to the attaching / detaching position C or the image forming position A, or in the opposite direction. regulate. At this time, the restricting member 36 is located at the restricting position D. The urging force of the urging member 37 that urges the restricting member 36 restricts the movement of the guided portions 33e1 and 33e3 to the outside when the second holding portion 38 is held and the unit 200 is rotated. . At the attachment / detachment position B, the guided portions 33e1 and 33e3 move the restricting member 36 to the allowable position E in accordance with the attaching / detaching operation of the user, and set to an urging force that can get over the restricting member 36. Regarding the other cartridges 33 (33M, 33C, 33K), the guided portions 33e1 and 33e3 are regulated by the regulating member 36, so that they do not fall out of the unit 200. Further, since the top and bottom of the guided portions 33e1 and 33e3 are also regulated by the mounting portion 32l, even if the user grips the second gripping portion 38 and moves the unit 200 in the directions of the arrows X8 and X9, The cartridge 33Y does not come out to the outside.

  In the apparatus main body 100A, a spring member (biasing member) 48 is provided on the upper surface of the lower stay 110c of the main frame 110. When the unit 200 is rotated from the attaching / detaching position B in FIG. 14B to the image forming position A, as shown in FIG. 15A, at the position C before the image forming position A, The lower surface of the sub-frame 31 of the unit 200 abuts on the spring member 48 described above. FIG. 16B is an enlarged view of the unit 200 portion of FIG. Therefore, even if the user rotates the unit 200 downward with a certain strong force, the force can be received by the spring member 48. Since the urging force of the spring member 48 is sufficiently larger than the force generated downward due to the weight of the unit 200, the unit 200 stops in a state where the urging force is received by the spring member 48. At this time, the rotation restricted portion 31l (FIG. 6B) of the unit 200 is not in contact with the rotation restricting portion 80c (FIG. 7A) provided on the guide plate 80R, but from the image forming position A. Is located in the foreground. This position is referred to as a front / rear position C. By providing the spring member 48, when the user rotates the unit 200, the unit 200, the cartridge 33, the photosensitive unit 32, and the members in the apparatus main body 100A are prevented from being damaged by an impact or the like. can do. The spring member 48 only needs to be provided between the unit 200 and the apparatus main body 100 </ b> A, and may be provided in the unit 200. In other words, when the unit 200 is moved from the attachment / detachment position B to the image forming position A, the unit 200 may be configured to come into contact with both the unit 200 and the apparatus main body 100A. In this embodiment, a plate-like spring member is used as the spring member 48, but it may be formed of a coil spring or the like. The spring member 48 may be omitted depending on the weight of the unit 200 and the cartridge 33 inserted therein. FIG. 17 is a view when the spring member 48 is omitted. In this case, the unit 200 is positioned at the image forming position A with the lower surface of the subframe 31 directly received by the upper surface of the lower stay 110c of the main frame 110 without passing through the position C before attachment / detachment. As shown in FIG. 15A, the user stops gripping the second gripping portion 38 or the gripping portion 31m while the unit 200 is positioned at the front / removal position C, and closes the cover 10 from the open position H. It moves to the position G ((b) of FIG. 15). When the cover 10 is rotated to a position before the closing position G, the urging spring (pressing member) 35 provided on the inner surface side of the cover 10 is located at the attaching / detaching front position C. Abuts against a pressed portion 31p (FIG. 6) provided on the top plate 31C. Thereafter, the cover 10 is rotated in the closing direction against the urging force of the spring 35 and the spring member 48. Since the urging force of the urging spring 35 is larger than the urging force of the spring member 48, the unit 200 abuts the shaft portions 45L and 45R against the positioning portion 80a against the urging force of the spring member 48. Further, the rotation restricted portion 31l is brought into contact with the rotation restricting portion 80c provided on the guide plate 80R. As a result, the unit 200 is positioned at the image forming position A with respect to the apparatus main body 100A. Further, as shown in FIG. 9B, the locking claw portion 10b provided on the cover 10 side corresponds to the locking claw portion 36a provided on the maintenance button 36 side. When the cover 10 is sufficiently moved to the closed position G by further rotation of the cover 10 in the closing direction, the locking claw portion 10b on the cover 10 side is moved to the maintenance button 36 as shown in FIG. It engages (latching engagement) with the side locking claw 36a. As a result, the cover 10 is locked at the closed position G. The cover 10 is moved and biased in the opening direction by the compression reaction force (elastic force) of the spring 35 and the spring member 48, but is fixed to the apparatus main body 100A by the locking claws 10b and 36a as described above. Is done. Therefore, the unit 200 is stopped by being pressed at the image forming position A by being pressed against the apparatus main body 100A by the spring 35 ((b) in FIG. 1, (a) in FIG. 16). That is, the unit 200 forms an image by cooperation of the cover 10, the cover-side locking claw portion 10b, the maintenance button-side locking claw portion 10b, the spring 35, the rotation restricted portion 31l, and the rotation restriction portion 80c. Locked to position A. In the present embodiment, the example in which the biasing spring 35 is attached to the cover 10 has been described. However, the unit 200 may be provided with a biasing spring, and a part of the cover 10 may be brought into contact with the biasing spring. That is, any structure may be used as long as it is sandwiched between and in contact with both the unit 200 and the cover 10 in conjunction with the closing operation of the cover 10.

  The apparatus main body 100A includes cartridge urging members 51a to 51d that urge each cartridge 33 toward the corresponding photosensitive unit 32 in a state where the unit 200 is located at the image forming position A. The urging members 51 a to 51 d are provided at both ends in the longitudinal direction (left-right direction) of the cartridge 33, and two urging members 51 a to 51 d are provided for each cartridge 33. The urging members 51a to 51d are sequentially brought into contact with the rear end portions of the cartridges 33 in accordance with the rotation operation toward the image forming position A of the unit 200. By adopting a method in which the urging members 51 a to 51 d are sequentially brought into contact with the cartridge 33, the mounting property can be improved. That is, the load generated by the urging member can be distributed as compared with the method in which all the urging members are brought into contact with each other at a time, so that the load during operation can be reduced. As shown in FIG. 1B, when the unit 200 is positioned at the image forming position A, the cartridge 33 is urged in the direction of the arrow Y2 by the urging members 51a to 51d. The developing roller 33b accommodated in the cartridge 33 comes into contact with the drum 32a with a constant urging force by bringing the regulation roller 60 (FIG. 5) provided at both ends thereof into contact with the drum 32a. The urging force by the urging members 51a to 51d maintains a good contact state (or separated state) between the developing roller 33b and the drum 32a.

  When the unit 200 to which the cartridge 33 is mounted is positioned at the image forming position A, the guided portions 33e1 and 33e3 provided in the cartridge 33 are urged by the regulating member 36 as shown in FIG. It is located in a position that does not receive. That is, the guided portions 33e1 and 33e3 are located at positions where they do not contact the regulating member 36. At this time, a gap g is provided between the guided portions 33e1 and 33e3 and the regulating member 36. Accordingly, the urging force of the urging member 37 that urges the restricting member 36 is not affected by the urging force of the cartridge 33 with respect to the unit 32. Therefore, the urging force of the cartridge 33 can be maintained with high accuracy. Further, when the cartridge 33 moves from the attachment / detachment position B to the image forming position A (or when moving in the opposite direction), the size of the gap g is changed to a member of the apparatus main body 100A (cartridge urging members 51a to 51d). It is better to set the size so that it does not come into contact. As a result, it is possible to achieve both the high accuracy of the biasing force of the cartridge 33 on the drum 32a and the stable operation of the unit 200 described above.

  With the above operation, the image forming apparatus 100 is ready for an image forming operation (printing operation), and the above-described image forming operation is performed based on the image forming start signal (print start signal). That is, a drive output unit (not shown) on the apparatus main body side is connected to a gear 34b which is a drive input unit of the intermediate transfer member 34 of the unit 200 located at the image forming position A. The drum gear 32a1 of each photoconductor unit 32 is connected to the gear 34b. Further, the gear 50 of the developing roller 33b of each cartridge 33 is connected. In addition, the power supply system on the apparatus main body side is electrically connected to the electrical contacts of the photosensitive unit 32 and the cartridge 33. As a result, the image forming apparatus is ready for an image forming operation.

  As shown in FIG. 1B, the image forming apparatus 100 according to the present embodiment is substantially aligned in the horizontal direction with respect to the installation surface F, and includes a scanner unit 11, a cartridge 33, a drum 32a, an intermediate transfer member 34, and A conveyance path Z for the recording medium S is arranged. A cover 10 that also serves as a discharge tray is disposed above the apparatus 100, and a cassette 19 is disposed below the apparatus 100. Then, the laser beam L (LY / LM / LC / LK) from the scanner unit 11 is applied to the drum 32 a from the rear of the cartridge 33. Further, the developer images of the respective colors transferred from the respective drums 32a to the intermediate transfer body 34 are transferred to the recording medium S on the side opposite to the positions where the respective drums 32a are arranged with the intermediate transfer body 34 interposed therebetween. . Further, according to the present embodiment, the unit 200 is placed between the image forming position AA and the attaching / detaching position B in a state where the drum 32a is attached to the unit 200 and the cartridge 33 is detachably attached to the unit 200 (mounting portion 32l). You can rotate between them. Then, the cartridge 200 is attached to and detached from the unit 200 by rotating the unit 200 from the image forming position A to the attachment / detachment position B. With such a configuration, the apparatus 100 can be miniaturized.

(Replacement of cartridge and waste developer container)
As each cartridge 33 (33Y, 33M, 33C, and 33K) is used for image formation, the developer stored in the developer storage portion 33c of the cartridge 33 is consumed. Therefore, for example, a means (not shown) for detecting the developer remaining amount of each cartridge 33 is provided, and the control circuit unit 300 sets the detected remaining amount value to a preset threshold value for cartridge life warning or life warning. Compare with For the cartridge 33 whose detected remaining value is smaller than the threshold value, the display unit 102 ((a) of FIG. 1) provided in the operation unit 101 of the image forming apparatus 100 predicts the life of the cartridge 33. Alternatively, a life warning is displayed. Alternatively, a life warning or life warning about the cartridge 33 is displayed on the display unit (not shown) of the external host device 400. This prompts the user to prepare a cartridge for replacement, or prompts the user to replace the cartridge to maintain the quality of the output image. Further, with respect to the waste developer container 40, it is detected that the waste developer more than the specified amount is stored in the container, and this is displayed on the display unit 102 or the like to prompt the user to replace the container 40. Yes.

  In the image forming apparatus 100 of this embodiment, the replacement of each cartridge 33 mounted on the unit 200 and the replacement of the waste developer container 40 are performed by opening the cover 10 and opening the upper surface opening 100B of the apparatus main body 100A. Is made by As shown in FIG. 1B, the cover 10 that is locked at the closed position G is released from the closed state by using the maintenance button 36 disposed on the front surface of the apparatus main body 100A with a two-dot chain line in FIG. This is done by pressing the user as shown. When the user pushes the button 36 backward against a spring (not shown), the locking claw 36a on the button 36 escapes backward from the locking claw 10b on the cover 10 side as shown by a two-dot chain line. Latch release. As a result, the cover 10 is pushed up by the compression reaction force (elastic force) of the spring 35 and the spring member 48. The cover 10 rotates in the opening direction from the apparatus main body 100A by an angle corresponding to the operating length of the spring 35 and the spring member 48 (the length of restoration to the free length) around the hinge shaft 10a. That is, the cover 10 is automatically half-opened by the elastic force of the spring 35 and the spring member 48. FIG. 9B and FIG. 15B show the cover 10 in a half-open state. The button 36 then returns to its original position by the force (elastic force) of an urging spring (not shown) when the user releases the finger. At this time, since the latching claw portion 10b is positioned upward by the half-opening movement of the cover 10, it does not engage with the restored latching claw portion 36a ((b) of FIG. 9). The user puts his / her finger on the handle 10d of the cover 10 which is in the half-opened state, and opens the cover 10 to the open position H by manual operation as shown in FIG. By sufficiently opening the cover 10 to the open position H, the cover 10 is received by the stopper portion on the apparatus main body side, and the open state is stably maintained even when the rear hand is released. Alternatively, the open state is stably maintained even if the rear hand is released by being locked by a click stop mechanism or a catch mechanism. As a result, the upper surface opening 100B of the apparatus main body 100A is opened sufficiently large. Further, the unit 200 is released from the urging force (pressing) by the urging spring 35 by releasing the locking of the cover 10 with respect to the closed position G. As a result, the unit 200 moves from the image forming position A to the front / removal position C by the biasing force of the spring member 48. The unit 200 that has moved to the front / removal position C is exposed in the opening 100A that is opened when the cover 10 is opened. The user sees the unit 200 that has moved to the position C before the attachment / detachment, and is then instructed to operate the unit 200. That is, the user intuitively sees that the cartridge 33 attached to the unit 200 moves in the direction of the attachment / detachment position (movement in the direction of the arrow X9), and the user intuitively performs the next operation in the direction of the arrow X9 of the unit 200. Since the user can feel the operation, the user's operation can be assisted. Further, since the second gripping portion 38 of the cartridge 33Y and the gripping portion 31m of the sub-frame 31 pop out in the rotation direction of the unit 200 (direction of the opening 100B), the user can It is easy to recognize the part 31m and easily execute the subsequent operation. The user holds either the first holding part 38 or the holding part 31m, rotates the unit 200 in the direction of the arrow X9, and positions the unit 200 at the attachment / detachment position B ((b) of FIG. 14). . When the spring member 48 is not used (FIG. 17), the unit 200 located at the image forming position A is moved to the attachment / detachment position B while holding the second holding part 38 or the holding part 31m. As described above, the unit 200 located at the attachment / detachment position B is temporarily fixed at the attachment / detachment position B by the restriction portion 46 on the apparatus main body 100A side engaging the restricted portion 31n on the unit 200 side, and the image forming position A The movement in the direction is restricted. In this state, an operation of removing the cartridge 33 and the container 40 or the cartridge 33 or the container 40 in the direction opposite to the attaching operation described above is performed. That is, the cartridge 33 and the container 40 are configured to be detachable from the unit 200 when the unit 200 is positioned at the detachment position B.

  Here, with respect to the cartridge 33Y in which the unit 200 is located on the most downstream side in the rotation direction X9 from the image forming position A to the attachment / detachment position B, the attachment / detachment operation can be performed also at the position C before the attachment / detachment. This will be described with reference to FIG. 16B and FIG. As described above, the mounting portion 32l of the cartridge 33Y is divided into the first mounting portion 32l1 and the second mounting portion 32l2. The cartridge 33Y can be attached to and detached from the unit 200 at the attachment / detachment position B by using the first mounting portion 3211 (FIGS. 14A and 18). Further, the cartridge 33Y can be attached to and detached from the unit 200 by using the first and second attachment portions 32l1 and 32l2 at the front position C (or the attachment position B). That is, as shown by a two-dot chain line in FIG. 14A, the cartridge 33Y can be attached to and detached from the unit 200 from the direction of the arrow Y3 and the direction of the arrow Y4. As shown in FIG. 17, when the spring member 48 is omitted, the cartridge 33Y can be attached and detached at the image forming position A. Specifically, the cartridge 33Y is mounted such that the guided portions 33e1 and 33e3 of the cartridge 33Y are positioned corresponding to the second mounting portion 32l above the first and second mounting portions 32l1 and 32l2. Further, the guided portions 33e2 and 33e4 are positioned corresponding to the first mounting portion 32l1 ((a) of FIG. 19). Then, the cartridge 33Y is moved in the direction of the arrow Y3. As a result, the guided portions 33e1 and 33e3 enter the recess 32la of the second mounting portion 3212 (inside the recess 32la on the far side from the position of the regulating member 36). Further, the guided portions 33e2 and 33e4 enter the recess 32la on the front side of the position of the regulating member 36 ((b) in FIG. 19). Further, the cartridge 33Y is moved downstream in the mounting direction indicated by the arrow Y6. As a result, the cartridge 33Y is mounted on the unit 200 (FIG. 19C). Conversely, when the cartridge 33Y is removed from the unit 200 at the front position B (or the image forming position A), the first grip portion 38 is gripped and the cartridge 33Y is moved upstream in the mounting direction indicated by the arrow Y5. Thereafter, the guided portions 33e1 and 33e3 are detached from the second mounting portion 32l2 and the guided portions 33e2 and 33e4 are detached from the first mounting portion 32l1 by lifting in the cartridge 33Y arrow Y4 direction. Thereby, the cartridge 33Y is removed from the unit 200. Since the path of the first mounting portion 3211 and the second mounting portion 3212 intersect each other, the cartridge 33Y can be attached and detached in two different directions. Further, since the notch 31q is provided above the cartridge 33Y in the subframe 31 of the unit 200, the cartridge 33Y can be removed upward using the second mounting portion 32l2 as described above. Further, the cartridge 33Y can be mounted downward using the second mounting portion 3212. The notch 31q is a concave portion formed by the side plates 31L and 31R and the top plate 31C. By adopting the above-described configuration, the cartridge 33Y can perform the attaching / detaching operation without the operation of moving the unit 200 to the attaching / detaching position B. Therefore, the merit for the user is great.

  With the configuration of the image forming apparatus as described above, a configuration in which the cartridge 33 can be replaced without retracting the laser scanner unit (image exposure apparatus) 11 can be realized. As a result, the user can replace the developing cartridge 33 with relative ease. Further, the intermediate transfer member 34 is a cylindrical drum, and the unit 200 is configured to rotate around the central axis of the intermediate transfer member 34. Thereby, in the movement of the unit 200 between the image forming position A and the attachment / detachment position B, it is not necessary to retract the members in the apparatus main body 100A more than necessary. Further, since the internal cartridge 33 can be replaced without having to pull out the unit 200 outside the apparatus main body 1010A, it contributes to downsizing of the image forming apparatus 100. In this embodiment, the intermediate transfer member 34 for indirectly transferring from the drum 32a to the recording medium S has been described as an example of the transfer member. However, a method of directly transferring from the drum 32a to the recording medium S may be used. At this time, the transfer body 34 serves to directly transfer the developed image on the drum 32 a onto the recording medium S. Further, in this embodiment, the configuration in which the cartridge to be replaced is the developing cartridge 33 in the separation type process cartridge is shown. The cartridge to be replaced may be an integrated process cartridge in which the photosensitive unit 32 and the developing cartridge 33 are replaced as a unit.

  The configuration of the image forming apparatus 100 of the above embodiment is summarized as follows. The color electrophotographic image forming apparatus 100 forms a color image on a recording medium S. It has a plurality of cartridges 33 (33Y, 33M, 33C, 33K) for accommodating the developer. An image forming unit 200 is included. The unit 200 includes a transfer body 34 for transferring the developer image formed on the electrophotographic photosensitive drum 32a to the recording medium S, and a cartridge mounting portion 32l for mounting the cartridge 33. In the main body 100A of the image forming apparatus, the unit 200 is mounted between an image forming position A where image formation is performed and an attachment / detachment position B where a cartridge 33 different from the image formation position can be attached and detached. Is movable. Further, when the unit 200 moves from the attachment / detachment position B to the image forming position A, an urging member 48 for contacting both the unit 200 and the apparatus main body 100A is provided. The apparatus main body 100A has an opening 100B for attaching and detaching the cartridge 33. The opening / closing member 10 can open and close the opening 100B, and has an opening / closing member 10 that can take a closing position G for closing the opening 100B and an opening position H for opening the opening 100B. In addition, a pressing member 35 for contacting both the opening / closing member 10 and the image forming unit 200 is provided. Then, as the opening / closing member 10 moves from the open position H to the closed position G, the pressing member 35 comes into contact with both the unit 200 and the opening / closing member 10 and resists the urging force of the urging member 48, so that the unit 200. Is moved to the image forming position A. As the opening / closing member 10 is moved from the closed position G to the open position H, the unit 200 is released from being pressed by the pressing member 35, and is biased by the biasing member 48 in the direction from the image forming position A to the attaching / detaching position B. It is located at the position C before the moved attachment / detachment. Among the plurality of cartridges 33, the cartridge 33Y provided on the most downstream side in the moving direction from the image forming position A to the attachment / detachment position C has a grip portion 31m for gripping the unit 200 to rotate to the attachment / detachment position B. Have. Then, as the unit 200 moves from the image forming position A to the front / removal position C, the grip portion 31m moves toward the opening 100A. The unit 200 can rotate between the image forming position A and the attachment / detachment position C.

  100..Color electrophotographic image forming apparatus, 100A..Main body, 100B..Opening part 10 ... Opening / closing member, G..Closed position, H..Opening position, 200..Image forming unit, S .. Recording medium, 32a..electrophotographic photosensitive drum, 3211..cartridge mounting portion, 33 (33Y.33M.33C.33K) .. cartridge (developing cartridge), 34..transfer body, 35..pressing member, 31 m ..38..Grip part, A..Image forming position of image forming unit, B..Cartridge detaching position of image forming unit, C..Front position of detaching, 48.

Claims (5)

A color electrophotographic image forming apparatus for forming a color image on a recording medium,
A plurality of cartridges containing developer;
A transfer body for transferring the developer image formed on the electrophotographic photosensitive drum) to the recording medium, and a cartridge mounting portion for mounting the cartridge, and with the cartridge mounted, In the main body of the color electrophotographic image forming apparatus, an image forming unit capable of moving between an image forming position where image formation is performed and an attachment / detachment position where the cartridge different from the image formation position is attachable / detachable;
An urging member for contacting both the image forming unit and the apparatus main body when the image forming unit moves from the attach / detach position to the image forming position;
A color electrophotographic image forming apparatus comprising: The apparatus main body includes an opening for attaching and detaching the cartridge;
An opening and closing member capable of opening and closing the opening, and an opening and closing member capable of taking a closed position for closing the opening and an opening position for opening the opening;
A pressing member for contacting both the opening / closing member and the image forming unit;
As the opening / closing member moves from the open position to the closed position, the pressing member abuts both the image forming unit and the opening / closing member and resists the biasing force of the biasing member. The color electrophotographic image forming apparatus according to claim 1, wherein the image forming unit is moved to the image forming position.   As the opening / closing member is moved from the closed position to the open position, the image forming unit is released from being pressed by the pressing member, and is moved from the image forming position to the detachable position by the urging force of the urging member. The color electrophotographic image forming apparatus according to claim 2, wherein the color electrophotographic image forming apparatus is located at a position in front of the attachment / detachment moved in the direction.   Among the plurality of cartridges, a cartridge provided on the most downstream side in the moving direction from the image forming position to the attaching / detaching position has a grip portion for gripping the image forming unit to rotate to the attaching / detaching position. 4. The color electronic apparatus according to claim 3, wherein the gripping portion moves toward the opening as the image forming unit moves from the image forming position to the front position of the attachment / detachment. Photo image forming apparatus.   5. The color electrophotographic image forming apparatus according to claim 1, wherein the image forming unit is rotatable between the image forming position and the attachment / detachment position.