JP2011215406A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which can reduce its weight while ensuring its accurate positioning by means of a positioning unit.SOLUTION: In the image forming apparatus, the positioning unit is mounted in the positioning place of an apparatus body from the opening side of an image forming space, and based on the mounting operation, pivotally supports the other-end support shaft of each photoreceptor drum, thereby positioning each photoreceptor unit relative to the apparatus body. In the image forming apparatus, the positioning unit has a positioning frame plate for positioning each photoreceptor unit to the apparatus body, the positioning frame plate has a plurality of positioning means for pivotally supporting the other-end support shaft of each photoreceptor drum, each positioning means is composed of a frame plate made of metal, and means other than each positioning means is composed of a frame plate made of resin.

Description

  The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile machine, or a multifunction machine having these functions combined, and in particular, a photosensitive unit having a photosensitive drum and a developing unit are provided in the apparatus body. The present invention relates to an image forming apparatus including a positioning unit for positioning with respect to the image forming apparatus.

  In general, in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile machine, or a multi-function machine having these functions, a photosensitive drum of an image forming unit, a charging device are provided for convenience of maintenance and inspection. The unit is composed of a unit (photoreceptor unit) such as a container and a drum cleaning device.

In addition, the color printing type image forming apparatus includes a plurality of photoconductor units for transferring magenta, cyan, yellow, and black toner images onto a sheet. These photoreceptor units are detachably disposed in the apparatus main body and are arranged in parallel on the intermediate transfer belt.

A toner image is formed on the electrostatic latent image of the original image by a developing unit disposed adjacent to the photosensitive drum of each photosensitive unit. Each photosensitive drum nips (presses) the intermediate transfer belt with the primary transfer roller, and transfers the toner image to the intermediate transfer belt by the primary transfer bias applied to the primary transfer roller.
As a result, a full color toner image in which magenta, cyan, yellow, and black toner images are superimposed is formed on the intermediate transfer belt.

  In this color printing type image forming apparatus, a plurality of photosensitive units (photosensitive drums) are positioned with respect to the apparatus main body in order to transfer a full color toner image to the intermediate transfer belt with high accuracy (high accuracy).

As a technique for positioning the photosensitive unit (photosensitive drum) with respect to the apparatus main body, the technique disclosed in Patent Document 1 includes a plurality of drum side units having photosensitive drums, and these drum side units are arranged in parallel. A photoconductor unit is formed by being supported by two side plates, a front beam and a rear beam.
In this photoconductor unit, both end support shafts of the photoconductor drum of each drum side unit are supported by two side plates, and each side plate is fixed to a front beam and a rear beam by screws. The photoreceptor unit is positioned with respect to the apparatus main body by being attached to the apparatus main body.

  However, in the technology disclosed in Patent Document 1, each side plate that supports both end support shafts of the photosensitive drum is formed by press-molding a metal plate, so that the weight of the photosensitive unit becomes heavy, and the image forming apparatus There is a problem that it is not possible to reduce the weight.

JP 2007-322733 A

  In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of reducing weight while ensuring accurate positioning by a positioning unit.

  According to a first aspect of the present invention, there is provided an image forming space formed in the apparatus main body, a plurality of photosensitive units that are detachably disposed in the apparatus main body, and a detachable attachment to the apparatus main body. A positioning unit for positioning the photosensitive unit with respect to the apparatus main body, wherein the plurality of photosensitive units have a photosensitive drum, and support both end support shafts of the photosensitive drum; The photosensitive drum is inserted into the image forming space from one end support shaft of the photosensitive drum and disposed in the apparatus main body. The positioning unit is attached to the positioning position of the apparatus main body from the opening side of the image forming space. Based on the other end support shaft of each photoconductor drum, and positioning the photoconductor unit with respect to the apparatus main body. A positioning frame plate for positioning the photosensitive units on the apparatus main body, and the positioning frame plate includes a plurality of positioning means for supporting the other end support shafts of the photosensitive drums. The present invention relates to an image forming apparatus characterized in that the means is constituted by a metal frame plate and the positioning means other than the positioning means are constituted by a resin frame plate.

The invention according to claim 2 is characterized in that the positioning frame plate is composed of a metal base frame plate and a metal reinforcing frame plate attached to a part of the base frame plate, and each positioning means includes: The bearing is disposed between a bearing that pivotally supports the other end support shaft of the photosensitive drum, a first pressing member that presses the bearing from an axial direction of the support shaft of the photosensitive drum, and the first pressing member. A second pressing member that presses the bearing from the axial direction, wherein the first pressing member is formed on the basic frame plate, and the second pressing member is formed on the reinforcing frame plate, The image forming apparatus according to claim 1, wherein the bearing is positioned in the axial direction by one pressing member and the second pressing member.

According to the first aspect of the present invention, an image forming space formed in the apparatus main body, a plurality of photosensitive units arranged to be detachable in the apparatus main body, and a detachable attachment to the apparatus main body, The photoconductor unit includes a positioning unit for positioning the photoconductor units with respect to the apparatus main body, and the photoconductor units each have a photoconductor drum, and support both end support shafts of the photoconductor drum. The one end support shaft of the photosensitive drum is inserted into the image forming space and disposed in the apparatus main body, and the positioning unit is attached to the positioning position of the apparatus main body from the opening side of the image forming space. In the image forming apparatus, based on the operation, the other end supporting shaft of each of the photosensitive drums is pivotally supported to position each of the photosensitive units with respect to the apparatus main body. And a positioning frame plate for positioning the photosensitive unit on the apparatus main body, the positioning frame plate having a plurality of positioning means for supporting the other end support shaft of the photosensitive drum, Since each positioning means is composed of a metal frame plate and other than the positioning means is composed of a resin frame plate, the positioning means for pivotally supporting the other end support shaft of the photosensitive drum is provided as a resin frame. If it is made of a metal frame plate that is stiffer than the material, even if the other end support shaft of each photoconductive drum is pivotally supported to receive the photoconductive drum, the deformation due to this is minimized, and Can be positioned.
Further, if the portion other than the positioning means is formed of a resin frame plate, the weight of the entire positioning unit can be suppressed.
This makes it possible to reduce the weight of the positioning unit while maintaining the positioning accuracy of the positioning unit.
In addition, since the resin frame plate other than the positioning means is configured, the resin frame plate can be processed into a complicated shape (resin molding), and the number of parts can be reduced and the degree of freedom of the configuration of the positioning frame plate can be increased. It becomes possible.

According to a second aspect of the present invention, the positioning frame plate is composed of a metal base frame plate and a metal reinforcing frame plate attached to a part of the base frame plate, and the positioning means. Includes a bearing that supports the other end support shaft of the photosensitive drum, a first presser member that presses the bearing from the axial direction of the support shaft of the photoconductor drum, and the bearing between the first presser member. And a second presser member that presses the bearing from the axial direction, the first presser member is formed on the basic frame plate, and the second presser member is formed on the reinforcing frame plate, Since the bearing is positioned in the axial direction by the first pressing member and the second pressing member, only the portion forming the positioning means is made of a metal base frame. Since it reinforced with arm and reinforcing members, while improving the accuracy for supporting the supporting shaft of the positioning and the photosensitive drum bearings, it is possible to reduce the weight of the positioning frame plate.
Further, since the bearing is positioned in the axial direction by the first pressing member and the second pressing member, the other end support shaft of the photosensitive drum can be supported with high accuracy.

1 is a diagram illustrating an overall configuration of an image forming apparatus according to the present invention. FIG. 2 is an enlarged view showing a relationship between a photosensitive unit, a developing unit, and a positioning unit in FIG. 1. FIG. 2 is a perspective view illustrating a relationship among a photosensitive unit, a developing unit, and a positioning unit in FIG. 1. It is a front perspective view which shows the specific structure of the positioning unit of FIG. It is a back perspective view which shows the specific structure of the positioning unit of FIG. It is a disassembled front perspective view which shows the structure of the positioning frame board of the positioning unit of FIG. It is an expanded sectional view which shows the structure of the 1st pressing member of the positioning plate of FIG. It is an expanded sectional view which shows the structure of the 2nd pressing member of the positioning plate of FIG. It is an assembly front perspective view which shows the structure of the positioning frame board of the positioning unit of FIG. FIG. 5 is an assembled rear perspective view showing a configuration of a positioning frame plate of the positioning unit of FIG. 4. It is an expanded sectional view which shows the state which positioned the bearing with the 1st and 2nd pressing member of the positioning plate of FIG. It is a side view of the positioning unit of FIG. FIG. 5 is a cross-sectional view showing a connection relationship between a toner hopper of the positioning unit of FIG. 4 and a developing unit. FIG. 5 is a cross-sectional view showing a connection relationship between the positioning unit of FIG. 4 and a photosensitive unit. It is a principal part enlarged view which shows the state before attaching a positioning unit to an apparatus main body. It is a principal part enlarged view which shows the state which attached the positioning unit to the apparatus main body.

An image forming apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing the overall configuration of an image forming apparatus according to the present invention. FIG. 2 is an enlarged view showing the relationship between the photoconductor unit, the developing unit and the positioning unit of FIG. FIG. 3 is a perspective view showing a relationship among the photosensitive unit, the developing unit, and the positioning unit of FIG. FIG. 4 is a front perspective view showing a specific configuration of the positioning unit of FIG. FIG. 5 is a rear perspective view showing a specific configuration of the positioning unit of FIG. 6 is an exploded front perspective view showing the configuration of the positioning frame plate of the positioning unit of FIG. FIG. 7 is an enlarged cross-sectional view showing the configuration of the first pressing member of the positioning plate of FIG. FIG. 8 is an enlarged cross-sectional view showing the configuration of the second pressing member of the positioning plate of FIG. FIG. 9 is an assembled front perspective view showing the configuration of the positioning frame plate of the positioning unit of FIG. FIG. 10 is an assembled rear perspective view showing the configuration of the positioning frame plate of the positioning unit of FIG. FIG. 11 is an enlarged cross-sectional view showing a state in which the bearing is positioned by the first and second pressing members of the positioning plate of FIG. FIG. 12 is a side view of the positioning unit of FIG. FIG. 13 is a cross-sectional view showing the connection relationship between the toner hopper and the developing unit of the positioning unit of FIG. FIG. 14 is a cross-sectional view showing a connection relationship between the positioning unit and the photosensitive unit in FIG. FIG. 15 is an enlarged view of a main part showing a state before the positioning unit is attached to the apparatus main body. FIG. 16 is an enlarged view of a main part showing a state in which the positioning unit is attached to the apparatus main body.

<Overall configuration of image forming apparatus>
1 to 3, an image forming apparatus (X) includes an apparatus main body (1), a plurality of photoconductor units (2M), (2C), (2Y), (2B), and a plurality of developing units (3M). ), (3C), (3Y), (3B) and a positioning unit (Y). The image forming apparatus (X) is a color printing type image forming apparatus that transfers a toner image onto a sheet as shown in FIGS.

  As shown in FIGS. 1 to 3, an image forming space (A) is formed in the apparatus main body (1). This image forming space (A) is formed over the width direction (H) of the apparatus main body (1) as shown in FIGS. 1 to 3, and as shown in FIG. 3, the front-rear direction of the apparatus main body (1). (F) is extended. Further, as shown in FIGS. 1 to 3, the image forming space (A) opens to the front side wall (1A) of the apparatus body (1) and is closed by the rear side wall (1B) of the apparatus body (1). ing.

  Further, as shown in FIG. 3, each photosensitive unit (2M), (2C), (2Y), (2B) and each developing unit (3M) are provided on the rear side wall (1B) of the apparatus main body (1). Drive means (M) for driving (3C), (3Y), and (3B) is arranged, and this drive means (M) is constituted by a drive motor, a plurality of transmission gears and the like (not shown). .

  The plurality of photoreceptor units (2M), (2C), (2Y), and (2B) form magenta, cyan, yellow, and black toner images as shown in FIGS. Each of these photoreceptor units (2M), (2C), (2Y), (2B) extends in the front-rear direction (F) of the apparatus main body (1) as shown in FIG. A frame (8) extending in (F) is provided.

  Each photoconductor unit (2M), (2C), (2Y), (2B) is arranged in the front-rear direction (1) from the frame (8) to the main body (1) as shown in FIGS. A collection cylindrical body (9) extending in F) is arranged. As shown in FIG. 14, the recovery cylindrical body (9) is open to a recovery space (B) in each of the photoreceptor units (2M), (2C), (2Y), and (2B).

As shown in FIG. 14, the recovery cylindrical body (9) has a recovery port (9A). Further, as shown in FIGS. 3, 14, and 15, a cylindrical opening / closing member (10) is fitted on the outer periphery of the recovery cylindrical body (9), and the recovery is performed by the cylindrical opening / closing member (10). The mouth (9A) is openable and closable. Further, as shown in FIGS. 3, 14 and 15, a coil spring (11) is fitted on the outer periphery of the recovery cylindrical body (9), and this coil spring (11) is connected to the cylindrical opening / closing member (10). ) And the frame (8). As shown in FIGS. 3 and 14, the coil spring (11) urges the cylindrical opening / closing member (10) toward the collection port (9A) (the front end side of the collection cylindrical body (9)). The collection opening (9A) is closed by the cylindrical opening / closing member (10).

As shown in FIGS. 1 and 2, the photosensitive units (2M), (2C), (2Y), and (2B) include a photosensitive drum (5), a charging roller pair (6), and a cleaning device ( 7), and these are integrated (unit).

As shown in FIGS. 1 to 3, the photosensitive drum (5) has both end support shafts (12A) and (12B). As shown in FIG. 3, the photosensitive drum (5) extends in the front-rear direction (F) of the apparatus main body (1), and both end support shafts (12A) and (12B) are shown in FIG. As described above, the photoconductor units (2M), (2C), (2Y), and (2B) are rotatably supported by the frame (8). Further, both end support shafts (12A) and (12B) of the photosensitive drum (5) protrude in the front-rear direction (F) from the frame (8) as shown in FIG.
As a result, each of the photosensitive units (2M), (2C), (2Y), and (2B) is supported by both end support shafts (12A) and (12B) of the photosensitive drum (5) as shown in FIGS. ) Is rotatably supported, and the photosensitive drum (5) is rotatable.

  As shown in FIGS. 1 to 3, the charging roller pair (6) extends in the front-rear direction (F) of the apparatus main body (1), and the photosensitive unit (2M), (2C), (2Y). , (2B) is rotatably supported by the frame (8). The charging roller pair (6) is in contact with the photosensitive drum (5) as shown in FIGS. 1 to 3, and the photosensitive drum (6) is charged by a charging bias applied from a charging bias power source (not shown). 5) The surface is uniformly charged to a negative potential.

  As shown in FIGS. 1, 2 and 14, the cleaning device (7) is disposed in the recovery space (B) of each photoconductor unit (2M), (2C), (2Y), (2B). And a cleaning roller (13) and a recovery screw member (14).

  As shown in FIGS. 1 to 3, the cleaning roller (13) extends in the front-rear direction (F) of the apparatus main body (1), and the photosensitive units (2M), (2C), (2Y), It is rotatably supported on the frame (8) of (2B). As shown in FIGS. 1 to 3, the cleaning roller (13) is in contact with the photosensitive drum (5) and removes toner remaining on the photosensitive drum (5).

As shown in FIGS. 1, 2, and 14, the recovery screw member (14) is arranged in the vertical direction (U) of the apparatus main body (1) and below the cleaning roller (13). As shown in FIG. 14, the recovery screw member (14) extends in the front-rear direction (F) of the apparatus main body (1), and is disposed across the recovery cylindrical body (9) and the recovery space (B). . Moreover, the collection | recovery screw member (14) is rotatably supported by the front-end | tip (9A) and flame | frame (8) of the collection | recovery cylindrical body (9), as shown in FIG.3 and FIG.14.
Accordingly, as shown in FIGS. 2 and 14, the cleaning device (7) removes the toner remaining on the photosensitive drum (5) by the cleaning roller (13), and removes the removed toner to the recovery screw member (14). ) To the collection port (9A).

  As shown in FIG. 3, the photosensitive unit (2M), (2C), (2Y), (2B) having the above-described configuration is connected to the image forming space (A) from the one end support shaft (12A) of the photosensitive drum (5). And placed in the apparatus main body (1). Each of these photoreceptor units (2M), (2C), (2Y), (2B) is juxtaposed in the width direction (H) of the apparatus main body (1) as shown in FIGS. From the one end (1a) side to the other end (1b) of the apparatus main body (1), the magenta photosensitive unit (2M), the cyan photosensitive unit (2C), and the yellow photosensitive unit (2Y). And a photosensitive unit (2B) for black.

  In addition, as shown in FIG. 3, when the photosensitive unit (2M), (2C), (2Y), (2B) is arranged in the apparatus main body (1), the rear side wall ( 1B) is connected to each transmission gear (not shown) of the driving means (M). The drive means (M) drives a drive motor (not shown), thereby passing through each transmission gear, the photosensitive drum (5), the charging roller pair (6), the cleaning roller (13), and the recovery screw member (14). Is driven to rotate.

Each of these photoreceptor units (2M), (2C), (2Y), (2B) is mounted on the apparatus main body (1) as shown in FIGS. 3 and 15, and is mounted on the photoreceptor drum (5). The other end support shaft (12B) and the collection cylindrical body (9) protrude from the opening of the image forming space (A).
Each of the photoreceptor units (2M), (2C), (2Y), and (2B) is pulled out from the image forming space (A) as shown in FIGS. It is made removable.

  A plurality of developing units (3M), (3C), (3Y), and (3B) are replenished with magenta, cyan, yellow, and black toners, and each photosensitive unit (2M), (2C), (2Y), It adheres to the photosensitive drum (5) of (2B). Each developing unit (3M), (3C), (3Y), (3B) is extended in the front-rear direction (F) of the apparatus main body (1) as shown in FIG.

Each of these developing units (3M), (3C), (3Y), and (3B) has a replenishing port (18) as shown in FIGS. As shown in FIGS. 1, 2 and 10, the supply port (18) opens into a supply space (C) in each of the developing units (3M), (3C), (3Y), (3B). Yes. Further, as shown in FIGS. 3, 13 and 15, the replenishing port (18) is opened and closed by an opening / closing member (19), and this opening / closing member (19) is shown in FIGS. As described above, the spring member (20) is biased toward the supply port (18). Thereby, as shown in FIG.3 and FIG.15, the opening-and-closing member (19) has made the replenishment port (18) into a closed state.

  Each of the developing units (3M), (3C), (3Y), (3B) is a cylindrical member that protrudes from one end in the front-rear direction (F) of the apparatus main body (1), as shown in FIGS. (22) is formed. As shown in FIG. 15, a cylindrical body (23) is fitted on the outer periphery of the cylindrical member (22). Further, as shown in FIG. 15, a coil spring (24) is fitted on the outer periphery of the cylindrical member (22), and the coil spring (24) includes a cylindrical body (23), a developing unit (3M), (3C ), (3Y), (3B). As shown in FIG. 12, the coil spring (24) urges the cylindrical body (23) toward the distal end side of the columnar member (22).

Each developing unit (3M), (3C), (3Y), (3B) houses a developing roller (15), a replenishing roller (16), and a replenishing screw member (17) as shown in FIGS. Thus, these parts are integrated (unit).

  As shown in FIGS. 1 and 2, the developing roller (15) is disposed so as to be in contact with the photosensitive drums (5) of the photosensitive units (2M), (2C), (2Y), and (2B). 3 and extends in the front-rear direction (F) of the apparatus body (1). The developing roller (15) is rotatably supported by the developing units (3M), (3C), (3Y), and (3B).

  As shown in FIGS. 1 and 2, the replenishing roller (16) is in contact with the developing roller (15), and adheres toner to the developing roller (15) by rotational driving. As shown in FIG. 3, the supply roller (16) extends in the front-rear direction (F) of the apparatus main body (1). The replenishing roller (16) is rotatably supported by the developing units (3M), (3C), (3Y), and (3B).

The replenishing screw member (17) is disposed so as to face the replenishing port (18), as shown in FIGS. As shown in FIGS. 3 and 13, the supply screw member (17) extends in the front-rear direction (F) of the apparatus main body (1). Further, it is rotatably supported by the developing units (3M), (3C), (3Y), and (3B).
As shown in FIG. 10, the replenishing screw member (17) conveys the toner replenished from the replenishing port (18) by rotational driving in the front-rear direction (F) of the apparatus main body (1).

The developing units (3M), (3C), (3Y) and (3B) having the above-described configuration are inserted into the image forming space (A) from the opposite side of the cylindrical member (22) as shown in FIG. Mounted on the main body (1).
These developing units (3M), (3C), (3Y), (3B) are juxtaposed in the width direction (H) of the apparatus main body (1), as shown in FIGS. From one end (1a) side to the other end (1b) of (1), a magenta developing unit (3M), a cyan developing unit (3C), a yellow developing unit (3Y), and a black developing unit. The units (3B) are arranged in this order.

  Further, each developing unit (3M), (3C), (3Y), (3B) has a photosensitive member unit (2M), (2C), (2Y), (2B) as shown in FIGS. ) And arranged in the apparatus main body (1), with the developing roller (15) facing the photosensitive drum (5).

As shown in FIG. 3, the developing units (3M), (3C), (3Y), and (3B) are arranged on the main body (1) of the apparatus main body (1). It is connected to each transmission gear (not shown) of the driving means (M). The drive means (M) drives a drive motor (not shown) to rotationally drive the developing roller (15), the supply roller (16), and the supply screw member (17) through each transmission gear.
As a result, each developing unit (3M), (3C), (3Y), (3B) attaches toner to the photosensitive drum (5) by the developing roller (15) as shown in FIGS. . Further, the toner replenished from the replenishing port (18) is conveyed in the front-rear direction (F) of the apparatus main body (1) by the rotational drive of the replenishing screw member (17).

Each of these developing units (3M), (3C), (3Y), (3B) forms an image of a cylindrical member (22) when mounted on the apparatus main body (1) as shown in FIGS. It protrudes from the opening of the space (A).
Each of the developing units (3M), (3C), (3Y), and (3B) is removed from the apparatus main body (1) by being pulled out from the image forming space (A) as shown in FIGS. It is made open.

As shown in FIGS. 1 to 3, the positioning unit (Y) is detachably attached to the apparatus main body (1) from the opening side of the image forming space (A), and is attached to the apparatus main body (1). The photosensitive units (2M), (2C), (2Y), (2B) and the developing units (3M), (3C), (3Y), (3B) are positioned with respect to the apparatus main body (1). .
As shown in FIG. 1, the positioning unit (Y) is arranged between the plurality of toner containers (51M), (51C), (51Y), (51B) and the paper feed cassette (54).

  As shown in FIG. 1, the image forming apparatus (X) includes a plurality of toner containers (51M), (51C), (51Y), (51B), an intermediate transfer belt (52), a fixing device (R), An exposure apparatus (Z) and a paper feed cassette (54) are provided.

  As shown in FIG. 1, a plurality of toner containers (51M), (51C), (51Y), and (51B) are in the vertical direction (U) of the apparatus main body (1) and in the image forming space (A). It is arranged on the upper side. Each of these toner containers (51M), (51C), (51Y), and (51B) stores magenta, cyan, yellow, and black toners, respectively. Further, as shown in FIG. 1, the toner containers (51M), (51C), (51Y), and (51B) are provided in the developing units (3M), (3C), (3Y), and (3B), respectively. Supply toner (magenta, cyan, yellow and black).

As shown in FIG. 1, the intermediate transfer belt (52) is in the vertical direction (U) of the apparatus main body (1), and is provided in each of the photoreceptor units (2M), (2C), (2Y), (2B). It is arranged on the upper side. As shown in FIG. 1, the intermediate transfer belt (51) extends across the width direction (H) of the apparatus main body (1) and is circulated and conveyed by a plurality of conveyance drums (55). Further, as shown in FIG. 1, the intermediate transfer belt (52) includes a photosensitive drum (5) of each photosensitive drum (2M), (2C), (2Y), (2B) and a primary transfer roller (56). ) Is pressed.
Further, as shown in FIG. 1, the intermediate transfer belt (52) is in pressure contact with a secondary transfer roller (58) disposed in the conveyance path (57).

  As shown in FIG. 1, the fixing device (R) is disposed in a conveyance path (57) on the downstream side of the intermediate transfer belt (52), and includes a heating drum (59) and a pressure roller (60). Yes.

  As shown in FIG. 1, the exposure apparatus (Z) is in the vertical direction (U) of the apparatus main body (1) and below the photosensitive unit (2M), (2C), (2Y), (2B). Arranged on the side. The exposure device (Z) modulates image information input from the control device (Q) into laser light corresponding to the digital image signal. By scanning and exposing the modulated laser beam to the photosensitive drums (5) of the photosensitive units (2M), (2C), (2Y), and (2B), image information is stored on the photosensitive drums (5). An electrostatic latent image of each corresponding color (magenta, cyan, yellow, black) is formed.

  As shown in FIG. 1, the paper feed cassette (54) is mounted on the lower side of the exposure device (Z) and stores a plurality of sheets.

<Image Forming Procedure of Image Forming Apparatus>
As shown in FIGS. 1 to 3, the control device (Q) of the image forming apparatus (X), when receiving a printing (image forming) command, drives each of the photosensitive unit (M) by driving the driving means (M). The photosensitive drum (5), the charging roller pair (6), the cleaning roller (13), and the recovery screw member (14) of 2M), (2C), (2Y), and (2B) are rotationally driven.
Further, as shown in FIGS. 1 to 3, the driving means (M) includes a developing roller (15), a replenishing roller (16) and a developing roller (15) of each developing unit (3M), (3C), (3Y), (3B). The replenishing screw member (17) is driven to rotate.
Further, as shown in FIG. 1, the control device (Q) circulates and conveys the intermediate transfer belt (52) by a plurality of conveying drums (55).

  As shown in FIGS. 1 and 2, the photosensitive drums (5) of the photosensitive units (2M), (2C), (2Y), and (2B) are made uniform by the charging bias of the charging roller pair (6). Charged to negative potential. Subsequently, as shown in FIG. 1, the exposure device (Z) modulates the image information input from the control device (Q) into a laser beam corresponding to the digital image signal, and the modulated laser beam is applied to each photoconductor. By scanning and exposing the photosensitive drums (5) of the units (2M), (2C), (2Y), and (2B), an electrostatic latent image is formed on each photosensitive drum (5).

The developing bias applied to the developing roller (15) of the magenta developing unit (3M) with respect to the electrostatic latent image formed on the photosensitive drum (5) of the magenta photosensitive unit (2M). The magenta toner is adhered by (negative potential). As a result, a magenta toner image is formed on the photosensitive drum (5) with respect to the electrostatic latent image.
During this time, the magenta toner image on the photosensitive drum (5) is primarily transferred to the intermediate transfer belt (52) by the primary transfer bias applied to the primary transfer roller (56) as shown in FIG.

The intermediate transfer belt (52) onto which the magenta toner image has been transferred is conveyed to the cyan photoconductor unit (2C) as shown in FIG. As shown in FIG. 1, a cyan toner is applied to the electrostatic latent image on the photosensitive drum (5) of the cyan photosensitive unit (2C) in the same manner as the magenta photosensitive unit (2M). An image is formed. As shown in FIG. 1, the cyan toner image is primary-transferred over the magenta toner image on the intermediate transfer belt (52).

  Similarly, the yellow toner image formed on the photosensitive drum (5) of the yellow photosensitive unit (2M) is superimposed on the magenta and cyan toner images of the intermediate transfer belt (52) as shown in FIG. The black toner image formed on the photosensitive drum (5) of the photosensitive unit (2B) for black is first transferred to magenta, cyan, cyan on the intermediate transfer belt (52) as shown in FIG. Primary transfer is performed on the yellow toner image. As a result, a full-color toner image is formed on the intermediate transfer belt (52).

  In this primary transfer, the toner remaining on the photosensitive drum (5) of each photosensitive unit (2M), (2C), (2Y), (2B) is removed by a cleaning roller (13) as shown in FIG. As shown in FIG. 14, the removed and removed toner is conveyed to the collection port (9A) by the collection screw member (14).

Then, the primary transfer intermediate transfer belt (52) is conveyed to the secondary transfer roller (58) as shown in FIG.
At the same time, as shown in FIG. 1, the control device (Q) feeds the paper in the paper feed cassette (54) to the transport path (57) by the pickup roller (61), and by a plurality of transport roller pairs (62). The sheet is conveyed to the intermediate transfer belt (52) and the secondary transfer roller (58) on the downstream side of the conveyance path (57).

  Subsequently, the sheet is nipped by the intermediate transfer belt (52) and the secondary transfer roller (58), and the full color toner image is secondarily transferred to the sheet. Then, the sheet on which the full color toner image is transferred is conveyed to the fixing device (R) as shown in FIG. As shown in FIG. 1, the fixing device (R) fixes a full-color toner image on a sheet by heating and pressing the sheet with a heating drum (59) and a pressure roller (60).

  As shown in FIG. 1, the sheet on which the full-color toner image is fixed is discharged from the transport path (57) to the discharge tray (63).

<Specific configuration of positioning unit>
Next, a specific configuration of the positioning unit (Y) will be described with reference to FIGS.

  2 to 12, the positioning unit (Y) includes a frame main body (100). The frame main body (100) includes a rectangular lower surface frame (101), a rectangular side frame (102), (103) and the like are made up of a resin frame member (104) and a metal positioning frame plate (501).

  As shown in FIGS. 2 to 5, the side frames (102) and (103) are disposed at both ends in the width direction (H) of the lower surface frame (101), and are configured integrally with the lower surface frame (101). Yes.

  As shown in FIGS. 3 and 4, the positioning frame plate (501) is disposed on the front end side in the front-rear direction (F).

  Further, as shown in FIGS. 2 and 5, a partition frame (105) is disposed on the frame member (104), and the partition frame (105) has a frame main body (105) as shown in FIGS. 100) is partitioned into an upper space (100U) and a lower space (100D) in the vertical direction (U).

  Here, a specific configuration of the positioning frame plate (501) will be described with reference to FIGS. 4 and 6 to 8.

  The positioning frame plate (501) is formed in a rectangular shape as shown in FIGS. 6, 9, and 10, and is composed of a metal base frame plate (502) and a metal reinforcing frame plate (503). It is configured. As shown in FIGS. 4 and 6 to 11, the basic frame plate (502) has an insertion opening window (106). The insertion opening window (106) opens in the upper space (100U) of the frame body (100) in the front-rear direction (F), as shown in FIGS.

  The reinforcing frame plate (503) is attached to a part of the base frame plate (502) as shown in FIGS. As shown in FIGS. 6, 9, and 10, the reinforcing frame plate (503) is disposed above the insertion opening window (106) of the basic frame plate (502).

  The positioning frame plate (501) includes a plurality of positioning means (504M), (504C), (504Y), and (504B), as shown in FIGS. These positioning means (504M), (504C), (504Y), and (504B) are formed on the basic frame plate (502) and the reinforcing frame plate (503) as shown in FIGS. ing. That is, each of these positioning means (504M), (504C), (504Y), (504B) is a basic frame positioned above the insertion opening window (106) as shown in FIGS. The plate (502) and the reinforcing frame plate (503) are formed.

  Each positioning means (504M), (504C), (504Y), (504B) includes a bearing (505), an insertion hole (506), and a plurality of first presser members as shown in FIGS. (507), an insertion hole (508), and a plurality of second pressing members (509).

  The insertion holes (506) and the plurality of first pressing members (507) of the positioning means (504M), (504C), (504Y), (504B) are as shown in FIGS. 4, 6, 7 and 10. And formed on the basic frame plate (502).

  As shown in FIGS. 4, 6 and 10, the insertion holes (506) are arranged at intervals in the width direction (H) of the positioning frame plate (501), and are formed in a circular cross section. Yes. Each of these insertion holes (506) penetrates in the front-rear direction (F: axial direction of the other end support shaft (12B) of the photosensitive drum (5)), as shown in FIGS. .

  As shown in FIGS. 4, 6, 7, and 10, the plurality of first pressing members (507) are arranged evenly around the inner periphery of the insertion hole (506), and the holding portion (507 </ b> A) and A presser part (507B) is provided.

  As shown in FIGS. 4, 6, 7, and 10, the holding portions (507 </ b> A) of the plurality of first pressing members (507) protrude in the front-rear direction (F) from the basic frame plate (502). Further, as shown in FIGS. 4, 6, 7, and 10, the presser portion (507 </ b> B) is bent and protrudes from the distal end side of each holding portion (507 </ b> A) to the insertion hole (506) side.

  Further, the insertion holes (508) of the positioning means (504M), (504C), (504Y), (504B) and the plurality of second pressing members (509) are as shown in FIGS. It is formed on a metal reinforcing frame plate (503).

  As shown in FIGS. 6, 8, and 9, the insertion holes (508) are arranged at intervals in the width direction (H) of the positioning frame plate (501), and are formed in a circular cross section. Yes. Each of these insertion holes (506) penetrates in the front-rear direction (F), as shown in FIGS.

  As shown in FIGS. 6, 8 and 9, the plurality of second pressing members (509) are arranged evenly around the inner periphery of the insertion hole (508), and extend in the front-rear direction from the reinforcing frame plate (503). It protrudes in (F).

In the positioning frame plate (501) configured as described above, the bearing (505) is inserted into each insertion hole (506) of the base frame plate (502) as shown in FIGS. 502). The bearing (505) is inserted into each insertion hole (506) from the opposite side of the plurality of first pressing members (507), as shown in FIGS.
Thereby, each bearing (505) is contact | abutted to the press part (507A) of a some 1st press member (507), as shown in FIG.4, FIG.6 and FIG.11. At this time, as shown in FIGS. 4 and 11, the bearing (505) is in contact with the presser portion (507A) on the side surface of the outer ring and does not hinder the rotation of the bearing.

  When the bearing (505) is inserted (arranged) into each insertion hole (506) of the metal base frame plate (502), the metal reinforcement frame plate (503) is attached and fixed to the base frame plate (502).

As shown in FIG. 6, each insertion hole (508) of the reinforcing frame plate (503) is opposed to each insertion hole (506) of the base frame plate (502).
In this state, when the reinforcing frame plate (503) is attached and fixed to the base frame plate (502) as shown in FIGS. 9 and 11, the plurality of second pressing members (509) of the respective insertion holes (508) are fixed. As shown in FIG. 11, the bearing (505) is in contact with the bearing (505) in a state where the bearing (505) is disposed between the plurality of first pressing members (507) of the insertion holes (506). Each second pressing member (509) is in contact with the outer ring side surface of the bearing (505) and does not hinder the rotation of the bearing.

As shown in FIG. 4, the positioning frame plate (501) is fixed to the frame member (104) with the basic frame plate (502) facing outward from the positioning unit (Y).
The basic frame plate (502) of the positioning frame plate (501) may be made of resin, thereby improving the accuracy of positioning the bearing and supporting the other end support shaft (12B) of the photosensitive drum (5). However, the weight of the positioning frame plate (501) can be reduced.

  The positioning unit (Y) includes a plurality of toner hoppers (108M), (108C), (108Y), and (108B), as shown in FIGS.

The plurality of toner hoppers (108M), (108C), (108Y), and (108B) are arranged in the upper space (100U) of the frame main body (100) as shown in FIGS. These toner hoppers (108M), (108C), (108Y), and (108B) are attached to the front frame plate (104) above the insertion opening window (106) as shown in FIG. The toner hoppers (108M), (108C), (108Y), and (108B) are juxtaposed at intervals in the width direction (H), as shown in FIGS. Located between each bearing (505).
As a result, the toner hoppers (108M), (108C), (108Y), and (108B) are arranged at positions that do not interfere with the bearings (505), as shown in FIG.

  Each toner hopper (108M), (108C), (108Y), (108B) is formed with a toner introduction port (109) that opens upward in the vertical direction (U), as shown in FIGS. The toner introduction port (109) is freely opened and closed by an introduction opening / closing member (110). As shown in FIG. 1, the toner inlets (109) of the toner hoppers (108M), (108C), (108Y), and (108B) are connected to the toner containers (51M), (51C), (51Y), ( 51B), and the toner (magenta, cyan, yellow, black) contained in each toner container (51M), (51C), (51Y), (51B) is transferred to each toner hopper (108M), (108C), (108Y) and (108B) are supplied.

  Each toner hopper (108M), (108C), (108Y), (108B) is formed with a toner opening (111) that opens downward in the vertical direction (U), as shown in FIGS. ing. As shown in FIGS. 13 and 15, the toner opening (111) is opened and closed by an opening / closing member (112), and the opening / closing member (112) is opened by a spring member (113). 111) and the toner opening (111) is closed.

As shown in FIG. 15, the open / close members (112) of the toner hoppers (108M), (108C), (108Y), and (108B) are connected to the developing units (3M), ( 3C), (3Y), and (3B). Further, as shown in FIG. 15, the opening / closing member (112) is a projection (114) that can freely contact the opening / closing member (19) of each developing unit (3M), (3C), (3Y), (3B). It has.
As a result, the toner hoppers (108M), (108C), (108Y), and (108B) pass through the toner opening (111) as shown in FIGS. 13 and 15, and the developing units (3M) and (3C). , (3Y), and (3B) can be replenished with each color (magenta, cyan, yellow, black), forming a toner replenishment path.
In each toner hopper (108M), (108C), (108Y), (108B), a screw member (123) is disposed as shown in FIG. 13, and the toner is released from the toner by the screw member (123). Transport to mouth (111).

  Further, as shown in FIGS. 2 and 5, the positioning unit (Y) includes a plurality of first receiving members (115M), (115C), (115Y), (115B), and a plurality of second receiving members (116M). , (116C), (116Y), (116B), a toner recovery pipe (117), and a toner recovery container (118).

  The plurality of first receiving members (115M), (115C), (115Y), (115B) are arranged in the upper space (100U) of the frame body (100), as shown in FIGS. It faces the insertion opening window (106) of the positioning frame plate (501). These first receiving members (115M), (115C), (115Y), and (115B) are arranged on the partition frame plate (105) at intervals in the width direction (H) as shown in FIGS. The recovery cylindrical body (9) of each of the photoreceptor units (2M), (2C), (2Y), and (2B) is formed into a freely insertable cylindrical body.

  The plurality of second receiving members (116M), (116C), (116Y), (116B) are arranged in the upper space (100U) of the frame body (100), as shown in FIGS. It faces the insertion opening window (106) of the positioning frame plate (501). These second receiving members (116M), (116C), (116Y), and (116B) are arranged on the partition frame plate (105) at intervals in the width direction (H) as shown in FIGS. The cylindrical members (22) of the developing units (3M), (3C), (3Y), and (3B) are formed in a cylindrical body that can be inserted.

As shown in FIG. 2, the toner recovery pipe (117) is attached to the partition frame plate (105) of the frame body (100), and is arranged over the width direction (H). As shown in FIGS. 2 and 14, the toner recovery pipe (117) includes the first receiving members (115M), (115C), (115Y), (115B) and the second receiving members (116M), ( 116C), (116Y), and (116B).
Thus, the plurality of first receiving members (115M), (115C), (115Y), (115B) and the toner recovery pipe (117) are connected to the respective photoreceptor units (2M), (2C), (2Y), ( 2B) forms a toner recovery path for recovering toner from the cleaning device (7). Further, the staying toner in each developing unit (3M), (3C), (3Y), (3B) is transferred from the second receiving member (116M), (116C), (116Y), (116B) to the toner recovery pipe (117). ).
A screw member (not shown) is disposed in the toner recovery pipe (117), and the recovered toner is conveyed to the toner recovery container (118) by the screw member.

  As shown in FIGS. 2 and 5, the toner recovery container (118) is accommodated in the lower space (100D) of the frame body (100). As shown in FIG. 2, the toner recovery container (118) is connected to a toner recovery pipe (117), and is recovered from each of the photoreceptor units (2M), (2C), (2Y), and (2B). Contains toner.

<Specific configuration of main body side positioning means and hook means>
As shown in FIGS. 2, 4, and 12, the image forming apparatus (X) and the positioning unit (Y) include a main body side positioning unit (130) and a hook unit (141).

As shown in FIGS. 2, 4 and 15, the main body side positioning means (130) includes positioning pins (135) and (136) and positioning holes (137) and (138). As shown in FIG. 2, the main body side positioning means (130) is arranged on a line (a) connecting the axes of the other end support shafts (12A) of the photosensitive drums (5) mounted on the apparatus main body (1). Is positioned at the positioning position (P).
The positioning pins (135) and (136) are arranged in the positioning unit (Y) as shown in FIGS. The positioning pins (135) and (136) are fixed to the positioning frame plate (501) of the frame main body (100) with an interval in the width direction (H) as shown in FIGS. ing. Further, as shown in FIG. 2, the positioning pins (135) and (136) are positioned on both ends of the positioning frame plate (501) in the width direction (H).

As shown in FIG. 15, the positioning holes (137) and (138) are formed on the front side wall (1A) of the apparatus main body (1) and face the positioning pins (135) and (136). . As shown in FIG. 12, the positioning hole (137) is formed in a long hole having the same width as the positioning pin (135), and the positioning hole (138) is formed in the same diameter as the positioning pin (136). Has been.
Accordingly, the positioning unit (Y) is positioned in the apparatus main body (1) by inserting the positioning pins (135) and (136) into the positioning holes (137) and (138).

  As shown in FIGS. 4 and 12, the hook means (141) includes a plurality of hook members (142) and (143) and a plurality of hook holes (144) and (145).

  As shown in FIGS. 4 and 12, these hook members (142) and (143) are arranged inside the side frames (102) and (103) of the frame member (104), respectively. As shown in FIG. 12, the hook members (142) and (143) are rotatably attached to the side frames (102) and (103) by a rotating shaft body (145).

  Further, as shown in FIG. 12, the hook members (142) and (143) are rotationally restricted by restriction protrusions (146), and the restriction protrusions (146) are spring members as shown in FIG. (Not shown) is urged to protrude from the side frames (102) and (103). As shown in FIG. 12, the restricting protrusion (146) contacts the hook members (142) and (143) to restrict the rotation of the hook members (142) and (143).

When the hook members (142) and (143) are rotated, the restricting projections (146) are retracted as shown in FIG. 12, and the rotation restriction of the hook members (142) and (143) is released. To do.
Each of these hook members (142), (143) protrudes from the positioning frame plate (501) of the frame body (100) to the front side (apparatus body (1) side) as shown in FIGS. .

  As shown in FIG. 12, the hook holes (144) and (145) are formed in the front side wall (1A) of the apparatus main body (1), and the hook members (142) and (143) are inserted, The positioning unit (Y) is mounted on the apparatus main body (1).

<Positioning procedure by positioning unit>
Next, the positioning procedure of the positioning unit (Y) will be described.

The operator opens an opening / closing door (not shown) of the apparatus main body (1) shown in FIG. 1, and each photosensitive unit (2M), (2C), (2Y), (2B) is a photosensitive drum (5). Is inserted into the image forming space (A) from the one end support shaft (12A) and arranged in parallel with the apparatus main body (1) (see FIGS. 1 to 3).
Also, as shown in FIGS. 1 to 3, the operator inserts the developing units (3M), (3C), (3Y), and (3B) into the image forming space (A), and the apparatus main body (1 ) In parallel.

  When mounted on the apparatus main body (1), each photosensitive unit (2M), (2C), (2Y), (2B) is connected to the other end support shaft (12B) of the photosensitive drum (5) as shown in FIG. ) And the recovery cylindrical body (9) protrude from the opening of the image forming space (A). Further, as shown in FIG. 12, each developing unit (3M), (3C), (3Y), (3B) is part of an image forming space including a cylindrical member (22) and an opening / closing member (19). It protrudes from the opening of (A).

  As shown in FIGS. 2 and 15, the operator lifts the positioning unit (Y) and performs the following operation operations [1] to [5].

[1] As shown in FIG. 15 and FIG. 16, the operator places each photoconductor unit (2M), (2C), (2Y), (2B) in each bearing (505) of the positioning unit (Y). The other end support shaft (12B) of the photosensitive drum (5) is inserted.
At this time, as shown in FIGS. 4 and 9 to 11, the bearings (505) are moved in the front-rear direction (F: axial direction) by the pressing members (507) and (509) of the positioning frame plate (501). Since it is positioned, the other end support shaft (12B) of each photosensitive drum (5) is positioned with high accuracy on the apparatus main body (1).

[2] As shown in FIG. 15 and FIG. 16, the operator places each photoconductor unit in each first receiving member (115M), (115C), (115Y), (115B) of the positioning unit (Y). The collection cylindrical body (9) of (2M), (2C), (2Y), (2B) is inserted.
Based on this insertion operation, as shown in FIGS. 14 and 16, the open / close cylindrical body (10) is connected to each of the collection cylindrical bodies (9), as shown in FIG. 14 and FIG. (115Y), (115B) abuts against the spring force of the coil spring (11) and is moved to each photosensitive unit (2M), (2C), (2Y), (2B) side, and the recovery port ( 9A) is opened.
As a result, the recovery space (B) of each photoconductor unit (2M), (2C), (2Y), (2B) is communicated with the toner recovery pipe (117) as shown in FIG. Then, the toner recovered from each photosensitive drum (5) is accommodated in the toner recovery container (118) through the toner recovery pipe (117) by the rotational drive of the recovery screw member (14).

[3] As shown in FIGS. 15 and 16, the operator places each developing unit (116M), (116C), (116Y), (116B) in each of the developing units (116M). 3M), (3C), (3Y), (3B) cylindrical member (22) is inserted.
Based on this insertion operation, each cylindrical body (23) abuts on each second receiving member (116M), (116C), (116Y), (116B) as shown in FIG. It is moved to each developing unit (3M), (3C), (3Y), (3B) against the spring force of 24).
Thereby, the replenishment space (C) of each developing unit (3M), (3C), (3Y), (3B) is communicated with the recovery path of the recovery pipe (117).

  [4] Also, as shown in FIGS. 12 and 16, the operator inserts the positioning pins (135) and (136) of the positioning frame plate (501) into the positioning holes (137) and (137) of the apparatus main body (1). 138). At this time, the displacement of the positioning unit (Y) with respect to the apparatus main body (1) is absorbed by the positioning pins (135) and the positioning holes (137), as shown in FIGS.

[5] Further, based on the mounting operation of the positioning unit (Y), the open / close members (112) of the toner hoppers (108M), (108C), (108Y), and (108B) are shown in FIGS. As described above, the toner abuts against the developing units (3M), (3C), (3Y), (3B) and is moved to the positioning unit (Y) side against the spring force of the spring member (113) to release the toner. Open mouth (111).
In conjunction with this, the open / close members (19) of the developing units (3M), (3C), (3Y), (3B) are connected to the open / close members (112) of the open / close members (112) as shown in FIGS. Abutting against the protrusion (114) and moving toward the developing units (3M), (3C), (3Y), (3B) against the spring force of the spring member (20), the supply port (20) is moved. Open.
As a result, the replenishment paths of the toner hoppers (108M), (108C), (108Y), and (108B) are as shown in FIG. 13 with the developing units (3M), (3C), (3Y), and (3B). The toner containers (51M), (51C), (51Y), and (51B) shown in FIG. 1 are connected to the replenishment space (C), and toner (magenta, cyan, yellow, black) of each color is supplied to each developing unit ( 3M), (3C), (3Y) and (3B).

As described above, when the operator positions and attaches the positioning unit (Y) to the apparatus main body (1) as shown in FIGS. 2 and 15, next, as shown in FIGS. 2 and 12. The hook members (142) and (143) are rotated.
In addition, as shown in FIG. 12, each hook member (142), (143) is based on each hook hole (144), (144) of an apparatus main body (1) based on the mounting operation of the positioning unit (Y) by an operator. 145).
Based on this rotation operation, the rotation restriction of each restriction protrusion (146) is released, and the hook members (142) and (143) are vertically moved with the rotation shaft body (145) as the center as shown in FIG. It rotates upward in the direction (U) and is locked in the hook holes (144) and (145). Then, as shown in FIG. 9, each restricting projection (146) is returned by a spring member (not shown) to restrict the rotation of each hook member (142), (143).
As a result, the positioning unit (Y) is attached to the apparatus main body (1) as shown in FIGS.

<Removal procedure of positioning unit>
When an operator performs maintenance, inspection, and replacement of each photosensitive unit (2M), (2C), (2Y), (2B) and each developing unit (3M), (3C), (3Y), (3B) 1, the open / close door (not shown) of the apparatus main body (1) is opened, and the hook members (141) and (142) of the positioning unit (Y) are rotated. As a result, the hook members (141) and (142) are unlocked, and the positioning unit (Y) can be removed (see FIG. 12).

Subsequently, as shown in FIGS. 15 and 16, the operator holds the positioning unit (Y) and removes it from the apparatus main body (1).
At this time, the positioning unit (Y) is separated from the apparatus main body (1) by the spring force of the coil springs (11) and (24) as shown in FIGS.

[A] Based on the removal operation of the positioning unit (Y), each photosensitive member unit (2M) is moved from each first receiving member (115M), (115C), (115Y), (115B) of the positioning unit (Y). ), (2C), (2Y), and (2B), the recovery cylindrical body (9) is removed (see FIG. 15).
Thereby, as shown in FIG.14 and FIG.15, each cylindrical opening-and-closing member (10) is moved to the collection port (9A) side by the spring force of a coil spring (11), and makes a collection port (9A) a closed state. To do.
As a result, the recovery space (B) of each photoconductor unit (2M), (2C), (2Y), (2B) is, as shown in FIG. 15, the toner recovery pipe (117) of the positioning unit (Y). Since the communication is cut off, the collected toner can be prevented from being scattered by the removal operation of the positioning unit (Y).
Further, from the second receiving members (116M), (116C), (116Y), (116B) of the positioning unit (Y), the cylinders of the developing units (3M), (3C), (3Y), (3B). The member (22) is removed.

[B] Based on the removal operation of the positioning unit (Y), the open / close member (112) of each toner hopper (108M), (108C), (108Y), (10B) is as shown in FIGS. Then, the spring force of the spring member (113) is moved to the toner opening (111) side to close the toner opening (111).
In conjunction with this, the open / close member (19) of each developing unit (3M), (3C), (3Y), (3B) is provided with a spring force of the spring member (20) as shown in FIGS. Is moved to the supply port (18) side to close the supply port (18).
As a result, the communication between the toner hoppers (108M), (108C), (108Y), (108B) and the developing units (3M), (3C), (3Y), (3B) is blocked. The removal operation of Y) can prevent the collected toner from scattering.

  The operator transports the positioning unit (Y) to the outside of the apparatus main body (1) and, as shown in FIG. 1, each photosensitive unit (2M), (2C), (2Y), (2B), each development Remove the units (3M), (3C), (3Y), and (3B) from the image forming space (A), and perform maintenance, inspection, and replacement.

  The present invention is suitable for an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, or a multifunction machine having these functions.

X Image forming apparatus Y Positioning unit A Image forming space 2M Photosensitive unit (for magenta)
2C photoconductor unit (for cyan)
2Y photoconductor unit (for yellow)
2B Photosensitive unit (for black)
5 Photosensitive drum 12A One end support shaft 12B The other end support shaft 501 Positioning frame plate

Claims (2)

An image forming space formed in the apparatus main body, a plurality of photoconductor units that are detachably arranged in the apparatus main body, and a detachable attachment to the apparatus main body, and the respective photoconductor units are attached to the apparatus main body. Comprising a positioning unit for positioning with respect to
The plurality of photosensitive units are:
A photosensitive drum, which supports both end support shafts of the photosensitive drum, is inserted into the image forming space from one end support shaft of the photosensitive drum, and is disposed in the apparatus main body;
The positioning unit is
The photosensitive drum is attached to the positioning position of the apparatus main body from the opening side of the image forming space, and based on this attachment operation, the photosensitive drum unit is attached to the apparatus main body by pivotally supporting the other end support shaft of the photosensitive drum. In an image forming apparatus for positioning with respect to
The positioning unit is
A positioning frame plate for positioning each of the photoreceptor units on the apparatus main body;
The positioning frame plate is
A plurality of positioning means for supporting the other end support shaft of each photosensitive drum;
An image forming apparatus characterized in that each positioning means is constituted by a metal frame plate, and other than each positioning means is constituted by a resin frame plate. The positioning frame plate is
It is composed of a metal base frame plate, and a metal reinforcing frame plate attached to a part of the base frame plate,
Each positioning means includes
A bearing that pivotally supports the other end support shaft of the photosensitive drum;
A first pressing member for pressing the bearing from the axial direction of the support shaft of the photosensitive drum;
The bearing is disposed between the first pressing members, and includes a second pressing member that presses the bearing from the axial direction;
The first pressing member is formed on the basic frame plate, and the second pressing member is formed on the reinforcing frame plate.
The image forming apparatus according to claim 1, wherein the bearing is positioned in the axial direction by the first pressing member and the second pressing member.

Images