JP2007323006A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device having a drum cartridge and a developing cartridge separately, which improves the detachability of the drum cartridge, also improves usability, and prevents a damage and deformation of the drum, when the developing cartridge is attached or detached. <P>SOLUTION: The image forming device has the developing cartridge that is spaced in conjunction with the opening and closing of the door for the drum cartridge. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an electrophotographic system, and more particularly to an image forming apparatus having a plurality of developing devices.

(Description of electrophotographic technology)
In an image forming apparatus using an electrophotographic technique, an electrophotographic photosensitive drum (hereinafter referred to as a drum), which is an image carrier uniformly and uniformly charged by a charging unit, is selectively exposed by an exposure unit. A latent image is formed on the surface, the latent image is developed with a developer (hereinafter, toner), the developed image is transferred to a recording medium (paper, OHT, etc.), and further transferred onto the recording medium by a fixing unit. Image recording is performed by pressurizing and fixing the image. After the image transfer process, the drum is subjected to an image forming process starting from charging again after the residual toner is removed by the cleaning means.

(Formation of multicolor images)
As a means for forming a multicolor image using this electrophotographic technique, a system using a plurality of developing devices is known. In particular, when a full-color image is formed, four developing devices for yellow, magenta, cyan, and black are generally used. In such an image forming apparatus corresponding to a multicolor image, a configuration having a plurality of image carriers corresponding to each developing device and a configuration in which all the developing devices use one image carrier are known. It has been. In particular, as a configuration using one image carrier, a configuration in which each developing device is arranged along the outer periphery of the image carrier, and a configuration in which each developing device is sequentially moved to a predetermined position adjacent to the image carrier, Widely known.

  FIG. 12 shows an example of the image forming apparatus 100 in which the developing devices are arranged along the outer periphery of the drum 1. The image forming apparatus 100 includes an exposure apparatus, a laser unit 101, a fixing device 110, a recording paper cassette 105, a paper discharge tray 112, a transfer station T, a charging device 17, a cleaning device 18, a drum 1, and a yellow developing device dy. A magenta developing device dm, a cyan developing device dc, and a black developing device db. Each developing device (dy, dm, dc, db) is disposed along the outer peripheral surface of the drum 1. During image formation, the recording paper P, which is a recording medium, is transported from the recording paper cassette 105 to the transfer station T, and held on the outer peripheral surface of the transfer station T by a holding mechanism (not shown). On the other hand, the developing devices (dy, dm, dc, db) act on the drum 1 in sequence, and toner images of the respective colors are formed on the drum 1 in sequence. The formed toner images are sequentially transferred onto the recording paper P. The recording paper P is separated from the transfer station T when the toner images of all colors are transferred, and after the toner images are pressed and heated and fixed by the fixing device 110, the recording paper P is conveyed to the paper discharge tray 112. .

  FIG. 13 shows an example of an image forming apparatus 100 that sequentially moves each developing device to a predetermined position adjacent to the image carrier. The image forming apparatus 100 includes a charging device 17, a cleaning device 18, a laser unit 101, a fixing device 110, a recording paper cassette 105, a paper discharge tray 112, a drum 1, a yellow developing device dy, a magenta developing device dm, and a cyan developing device dc. , A black developing device db, a transfer drum, and a developing device switching mechanism 200. The developing device switching mechanism 200 is rotatable about the rotation shaft 201 and holds each developing device (dy, dm, dc, db). When forming an image, the developing device switching mechanism 200 sequentially conveys each developing device (dy, dm, dc, db) to a position adjacent to the drum 1, and the toner images of each color are sequentially formed on the drum 1. It is formed.

  The configuration in which each developing device is arranged along the outer periphery of the drum does not require a complicated developing device switching mechanism, whereas the configuration in which each developing device is sequentially moved to a predetermined position adjacent to the image carrier is a small diameter of the drum. There is a feature that it is easy to make.

(Description of process cartridge)
In such an image forming apparatus, a drum and process means such as a cleaning device, a charging device, and a developing device are made into a cartridge and are detachable from the image device. For example, Patent Document 1 proposes that the drum, the cleaning device, and each developing device be integrated into a cartridge. For example, Patent Document 2 discloses a drum cartridge in which the drum, the cleaning device, and the charging device are integrated. A configuration has been proposed in which each developing device for each color is a developing cartridge.

Although an apparatus for directly transferring a toner image from a drum to a sheet has been described here, a toner image of each color is transferred to an intermediate transfer member, and a plurality of color toner images formed on the intermediate transfer member are transferred to a sheet. The method is also described in Patent Document 3 and the like.
JP 3-214172 JP-A-62-250481 JP 5-19589

  As shown in FIG. 14, the image forming apparatus has a configuration in which the developing devices are arranged along the outer periphery of the drum. The drum cartridge A in which the drum, the cleaning device, and the charging device are integrated, and the developing devices of the respective colors are developed cartridges. In the image forming apparatus 100 in which 8Y, 8M, 8C, and 8B are detachable, the developing cartridges 8 can be arranged in the vertical direction. In this case, the attaching / detaching path of each of the developing cartridges 8Y, 8M, 8C, 8B can be in the direction approaching / separating from the drum 1 (right direction in FIG. 14).

  One drum cartridge A can be attached or detached in a direction along the drum central axis (in the direction perpendicular to the paper surface in FIG. 14), in a direction approaching or separating from each developing cartridge 8Y, 8M, 8C, 8B (in the left direction in FIG. 14), or The upper surface direction of the apparatus (upward direction in FIG. 14) can be selected by design. However, in either case, there were the following problems.

  When the attachment / detachment path of the drum cartridge A is in the direction along the drum central axis, the apparatus must be largely released on one end side of the drum 1, so that the support structure of the drum cartridge A is complicated. It was.

  When the attachment / detachment path of the drum cartridge A is in the direction of approaching / separating from the developing cartridge 8, the attachment / detachment path of the drum cartridge A and the attachment / detachment path of the developing cartridges 8Y, 8M, 8C, 8B are opposite side surfaces. There are problems that the operability of the forming apparatus is inferior and the substantial occupied area increases.

  When the attachment / detachment path of the drum cartridge A is in the direction of the upper surface of the apparatus, the developing cartridges 8Y, 8M, 8C, 8B are arranged along the outer periphery of the drum 1, so that even when only the drum cartridge A is attached / detached, In the case of the developing cartridge from the surface, in the illustrated example, it is necessary to retract the developing cartridges 8Y and 8M, which is troublesome.

  The present invention is an image forming apparatus having a configuration in which a plurality of developing devices are arranged along the outer periphery of a drum, wherein a drum cartridge in which a drum and a cleaning device are integrated is removable from the top surface side of the image forming apparatus, and An object of the present invention is to provide a configuration capable of improving usability when each cartridge is attached / detached in the image forming apparatus in which each color developing device is detachable from one side of the image forming device as a developing cartridge. To do.

As explained above, the first invention according to the present application is
A drum cartridge that has at least an electrophotographic photosensitive drum and is detachable from the image forming apparatus; and a developing cartridge that is separate from the drum cartridge and has at least a developer carrier and is detachable from the image forming apparatus;
An openable and closable drum cartridge door that covers the attachment and detachment path of the drum cartridge;
An image forming apparatus having a mechanism for moving the developing cartridge in conjunction with opening and closing of the drum cartridge door;
When the drum cartridge door is opened by the moving mechanism, the developing cartridge is separated from the photosensitive drum, and conversely, when the drum cartridge door is closed, the developing cartridge is close to the photosensitive drum.

The second invention according to the present application is:
A developing cartridge door that covers the mounting path of the developing cartridge separately from the drum cartridge door;
The image forming apparatus according to the first aspect, wherein the developing cartridge door includes a pressing unit that brings the developing cartridge close to the photosensitive drum.

The third invention according to the present application is:
The image forming apparatus according to any one of the first and second aspects, wherein the developing cartridge is plural and can form a color image.

  According to the present invention, since the developing cartridge 8 is retracted in conjunction with the door 52 as described above, the drum cartridge A can be mounted without opening the developing cartridge door 51 and taking out or moving the developing cartridge 8. I can. That is, when the drum cartridge A is replaced, only the door 52 needs to be opened and removed.

  The drum cartridge door may be opened and closed when the drum cartridge is replaced, and the developer cartridge door may be opened and closed when the developer cartridge is replaced. The respective cartridges can be replaced without complicating workability, and usability can be improved.

  Further, the drum cartridge and the developing cartridge can be prevented from being damaged because the drum and the developing cartridge are not brought close to each other when the operator directly holds the cartridge.

  Further, it is not necessary to increase the thickness of the drum material in order to prevent its deformation in consideration of the contact with the developing cartridge, so that the cost can be reduced.

Example 1
FIG. 1 is a main sectional view of an image forming apparatus to which the present invention can be applied. FIG. 1 is a diagram showing a state in which the drum cartridge A and the four color developing cartridges 8Y, 8M, 8C, and 8B are mounted on the image forming apparatus main body 100 to enable image formation.

(Image forming device body configuration)
As shown in FIG. 1, the drum cartridge A and the developing cartridge 8 are configured to be detachable from the image forming apparatus main body 100. Here, the drum cartridge A is attached / detached in the vertical direction (upward in FIG. 1), and the developing cartridge 8 is attached / detached in the horizontal direction (rightward in FIG. 1). A drum cartridge door 52 covering the attaching / detaching path of the drum cartridge A and a developing cartridge door 51 covering the attaching / detaching path of the developing cartridge 8 are provided to be openable and closable. The drum cartridge door 52 is opened to connect the drum cartridge A to the developing cartridge door. 51 can be opened to mount the developing cartridge 8.

Here, the developing cartridge 8 has four colors of yellow 8Y, magenta 8M, cyan 8C, and black 8Y. Here, the drum cartridge A is mounted from above the image forming apparatus 100 so that the position of the drum 1 is accurately supported with respect to the image forming apparatus 100, and the drum positioning convex portion of the drum cartridge A inside the image forming apparatus 100. 2 is supported. Further, the developing cartridge 8 has four color developing cartridges 8Y, 8M, 8C, and 8B arranged vertically, mounted in the horizontal direction with respect to the drum 1, and arranged along the outer periphery of the drum 1. A cartridge guide 11 for mounting the developing cartridges 8Y, 8M, 8C, and 8B is provided. (FIG. 2) Further, the developing cartridges 8Y, 8M, 8C, and 8B have a moving mechanism (hereinafter referred to as a retracting member 54) that brings the developing cartridges 8Y, 8M, 8C, and 8B close to and away from the drum 1. (Fig. 7)
The attachment / detachment of the drum cartridge A and the developing cartridge 8 will be described later. The image forming apparatus main body 100 includes a laser unit 101, a reflection mirror 102, a recording paper cassette 105, a paper feed roller 106, a transfer station T, a fixing device 110, a paper discharge roller 111, a paper discharge tray 112, and the like.

(Drum cartridge configuration)
As shown in FIG. 1, the drum cartridge A cleans the drum 1 that is an image carrier that is rotatably supported, the charging device 17 that uniformly charges the surface of the drum 1, and the toner remaining on the drum 1. A cleaning device 18 is provided. The cleaning device 18 has cleaning means such as a blade, a fur brush, and a magnetic brush. Here, the non-contact corona charging device is used as the charging device 17 in FIG. 1, but a contact charging device using a conductive roller formed in a roller shape may be used. In addition, in order to be mounted and positioned on the image forming apparatus 100, the drum 1 has a drum positioning convex portion 2 that is coaxial with the drum 1 and protrudes at both ends of the drum cartridge A.

(Developer cartridge configuration)
Here, the configuration of the developing cartridges 8Y, 8M, 8C, and 8B will be described with reference to FIGS. The developing cartridges 8Y, 8M, 8C, and 8B each include a developing roller 4 that is a developer carrying member, a developing blade 5 that is a developer regulating member that regulates the layer thickness of the toner on the developing roller 4, and a toner containing a toner. The unit 6 and the toner storage unit 6 have a conveying unit (not shown) for conveying the toner toward the developing roller 4 and are integrally configured as developing cartridges 8Y, 8M, 8C, and 8B. A plurality of guide protrusions 10 to be mounted on the image forming apparatus 100 are provided at both ends in the longitudinal direction of the developing roller 4.

(Image forming operation)
An image forming operation in the image forming apparatus of this embodiment will be described. (Figure 1)
The surface of the drum 1 in the drum cartridge C is uniformly charged by the charging device 17 while rotating in the direction indicated by the arrow. Next, when an electrical signal corresponding to each color, here the yellow component, is transmitted to the laser unit 101, the light L modulated correspondingly is reflected by the reflecting mirror 102 and irradiated onto the surface of the drum 1. As a result, an electrostatic latent image corresponding to the image signal is formed on the photosensitive drum 1.

  The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing cartridge 8Y. That is, a voltage (for example, −500 V) having the same polarity and the same polarity as the charging polarity of the photosensitive drum 1 is applied to the toner supply roller 4Y so that the yellow toner adheres to the light irradiated portion on the photosensitive drum 1. Thus, so-called reversal development is performed. As an applied voltage, an AC voltage of several KV may be superimposed on a DC voltage of −500 V as necessary.

  Here, as a developing method, there are known two-component magnetic brush developing method, cascade developing method, touch-down developing method, shampoo developing method, cloud developing method, etc., but when developing with developing cartridge 8Y, other It is necessary to stop the developing operation of the developing cartridges 8M, 8C, and 8B. In order to stop the toner supply, a sufficient reverse bias voltage is applied to the toner supply rollers of the developing cartridges M, 8C, and 8B, and the toner supply rollers of the developing cartridges 8M, 8C, and 8B are stopped. Taken. Note that these methods may be arbitrarily combined to stop the developing operations of the developing cartridges 8M, 8C, and 8B.

  On the other hand, the recording paper P in the recording paper cassette 105 is fed by the paper feed roller 106 and wound around the transfer station T. By the way, in this embodiment, the photosensitive drum 1 and the transfer station T are arranged in parallel to each other in the axial direction thereof, and these are brought into contact with each other with a predetermined pressure by means (not shown) to form the transfer station T. .

  Then, yellow toner is transferred at the transfer station T on the recording paper P wound around the transfer station T, and a yellow visible image is formed. The transfer residual toner remaining on the drum 1 is removed by the cleaning device 18.

  The drum 1 is again uniformly charged by the charging device 17 and then irradiated with the light L corresponding to the magenta component to form an electrostatic latent image on the surface thereof. The electrostatic latent image is stored in the developing cartridge 8M. This is visualized as a visible image of magenta by the magenta toner. The magenta visible image is transferred onto the yellow visible image by repeatedly moving the transfer rotary member 107 carrying the recording paper P onto which the yellow toner is transferred to the transfer station T.

  In the same manner as above, a cyan toner image and a black toner image are sequentially formed on the photosensitive drum 1 by development with the developing cartridges 8C and 8B, and cyan toner and black toner are further transferred onto the recording paper P, and transferred. Thereafter, the recording paper P is peeled off from the transfer rotary member 107 by the separating means and sent to the fixing device 110. In the fixing device 110, the yellow toner image, the magenta toner image, the cyan toner image, and the black toner image transferred onto the recording paper P are fixed by heating and pressurizing, and the recording paper P that has been fixed on the toner image is discharged. The paper is discharged onto the paper tray 111.

  In this embodiment, a full color image is formed with four colors of yellow, magenta, cyan, and black. However, the present invention is not limited to this, and three colors of yellow, magenta, and cyan, or other colors are added. Of course, a full color image may be formed with four or more colors.

(Replacement of drum cartridge A and developing cartridge 8)
As described above, in this embodiment, the photosensitive drum 1 (hereinafter referred to as the drum 1), the charging device 17, and the cleaning device 18 are incorporated into one frame body 20 so as to be detachable from the apparatus main body 100 as a drum cartridge A. . In addition to the drum cartridge A, the developing cartridges 8Y, 8M, 8C, and 8B are detachably attached to the apparatus main body 100. Therefore, it is possible to flexibly cope with differences in the usage amounts of yellow, magenta, cyan, and black. That is, when any of the yellow, magenta, cyan, and black toners runs out, only the developing cartridge that has run out of toners can be replaced. The drum cartridge A can be replaced when it is detected that the waste toner chamber 18b of the cleaning device 18 is full or when the drum 1 reaches the end of its useful life.

(Removal of developer cartridge)
2, 3 and 4 are views when the developing cartridge 8Y is mounted. When the developing cartridge 8Y is mounted, first, as shown in FIG. 2, the developing cartridge door 51 is opened and the guide convex portion 10Y of the developing cartridge 8 is aligned with a predetermined place of each color, in the case of yellow, the cartridge guide 11Y. Insert horizontally. Here, the guide protrusions 10Y are arranged on both sides in the axial direction of the developing roller 4Y of the developing cartridge 8Y. As shown in FIG. 2, an abutting portion 11Ya is provided on the drum 1 side of the cartridge guide 11Y, and the position where the guide convex portion 10Y abuts against the abutting portion is the position of the predetermined developing cartridge 8Y. When the developer cartridge 8 is inserted to a predetermined position as shown in FIG. 3 and the developer cartridge door 51 is closed as shown in FIG. 4, the developer cartridge rear portion 8 a is moved by the pressurizing portion 13 provided on the door 51. By being pushed, the developing cartridge 8Y is fixed at a predetermined position. Therefore, even if the developing cartridge 8 is inserted to a predetermined position when it is mounted or not inserted to a predetermined position, the rear portion 8a of the developing cartridge 8 is pushed by the developing cartridge door 51 and is fixed at a predetermined position.

  When the developing cartridge 8 is taken out, the developing cartridge door 51 is opened in the reverse order of the mounting, and the exposed developing cartridge rear portion 8a is grasped and taken out.

Further, a detachable handle may be provided on the rear part 8a of the developing cartridge to facilitate detachment. (Not shown)
Although the yellow developing cartridge 8Y has been described above, the other developing cartridges 8M, 8C, and 8B can be similarly attached and detached.

  Note that the developing cartridge 8 may be attached and detached while the drum cartridge A is mounted on the apparatus main body 100. Therefore, the developing cartridge door 51 can be opened and closed regardless of whether the drum cartridge door 52 is opened or closed.

(Removal of drum cartridge)
5, 6, and 7 are views when the drum cartridge A is mounted. The drum cartridge A is attached and detached in the vertical direction. When the drum cartridge A is mounted, the drum cartridge door 52 on the upper surface of the image forming apparatus 100 is first opened (FIG. 5). In conjunction with the opening of the drum cartridge A until it can be removed (FIG. 6), all the developing cartridges 8 are separated from the position where they are in contact with the drum 1 to the positions where they are retracted from the drum 1 by the retracting member 54. (Figs. 6 and 9)
This separation mechanism will be described with reference to FIGS. FIG. 7 shows a state in which the door 52 starts to be opened, and the retracting member 54 is pulled in the direction of the arrow by the spring 53. In the position of FIG. 7, the retracting member 54 is not in contact with the guide convex portion 11 of the developing cartridge. The door 52 has a lever portion 52a. When the door 52 is further opened from the state of FIG. 7 to the state of FIG. 8, the lever portion 52a of the door 52 contacts the retracting member 54 and the retracting member 54 begins to move toward the developing cartridge 8 side. As shown in FIG. 9, when the door 52 is completely opened, the retracting member 54 pushes the guide convex portion 11 to retract the developing cartridge 8 to a position where the drum cartridge A can be taken out. Here, the retracted position of the developing cartridge 8 is as follows. First, the developing cartridges 8Y and 8M that overlap the attachment / detachment locus 14 of the drum cartridge A are retracted to a position that does not sufficiently overlap the attachment / detachment locus 14 as shown in FIG. The remaining developing cartridges 8C and 8B are retracted to a position where they are not sufficiently in contact with the drum 1 when the drum cartridge A is attached or detached. As described above, in the present embodiment, the retracting member 54 is brought into contact with the guide convex portion, but not limited to the guide convex portion 11, another place of the developing cartridge 8 may be brought into contact.

In the above embodiment, the lever 52a is provided on the door 52 and the retracting member 54 is interlocked. However, as another embodiment, the door 52 and the retracting member 54 may be interlocked by a link mechanism or the like. (Not shown)
Further, an opening / closing sensor for the door 52 may be provided, and the retracting member 54 may be moved by a force of a solenoid or the like in conjunction with the opening of the door 52. (Not shown)
When the door 52 is completely opened, the drum cartridge A is inserted into the image forming apparatus 100 along the guide 113. As shown in FIG. 10, the drum cartridge A is positioned by dropping the drum positioning projection 2 on the drum shaft into the positioning recess 113a. When the door 52 is closed, the retracting member 54 moves opposite to when the door 52 is opened, and the developing cartridge 8 contacts the drum 1. Then, the door 52 is completely closed to complete the mounting.

  As described above, the developing cartridge 8 is retracted in conjunction with the door 52, so that the drum cartridge A can be mounted without opening the developing cartridge door 51 and taking out or moving the developing cartridge 8. That is, when the drum cartridge A is replaced, only the door 52 needs to be opened and removed.

  As described above, the drum cartridge A and the developing cartridges 8Y, 8M, 8C, and 8B for the respective colors can be replaced without complicating the workability of the cartridge replacement by the operator.

  Further, the drum cartridge and the developing cartridge can be prevented from being damaged because the drum and the developing cartridge are not brought close to each other when the operator directly holds the cartridge.

  Further, the thickness of the material of the drum 1 can be reduced because it is not necessary to increase the thickness in order to prevent deformation in consideration of contact with the developing cartridge, and the cost can be reduced.

1 is a main cross-sectional view of an image forming apparatus in an embodiment of the present invention. FIG. 6 is an explanatory diagram of mounting of a developing cartridge in the embodiment of the present invention. FIG. 6 is an explanatory diagram of mounting of a developing cartridge in the embodiment of the present invention. FIG. 6 is an explanatory diagram of mounting of a developing cartridge in the embodiment of the present invention. It is explanatory drawing of drum cartridge mounting | wearing in embodiment of this invention. It is explanatory drawing of drum cartridge mounting | wearing in embodiment of this invention. It is explanatory drawing of drum cartridge mounting | wearing in embodiment of this invention. It is explanatory drawing of drum cartridge mounting | wearing in embodiment of this invention. It is explanatory drawing of drum cartridge mounting | wearing in embodiment of this invention. It is explanatory drawing of drum cartridge mounting | wearing in embodiment of this invention. It is explanatory drawing of the developing cartridge in embodiment of this invention. It is explanatory drawing of the image forming apparatus in the conventional form. It is explanatory drawing of the image forming apparatus in the conventional form. It is explanatory drawing of the image forming apparatus in the conventional form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drum 2 Drum positioning convex part 4 Developing roller 5 Developing blade 6 Toner accommodating part 8 Developing cartridge 8a Developing cartridge rear part
8Y developer cartridge (yellow)
8M developer cartridge (magenta)
8C developer cartridge (cyan)
8B Developer cartridge (Black)
DESCRIPTION OF SYMBOLS 10 Guide convex part 10Y Guide convex part 11Y Main body cartridge guide 11Y Yellow developing cartridge 11Ya Cartridge guide abutting part 13 Pressurizing part 14 Attachment / detachment locus 17 Charging device 18 Cleaning device 51 Door for developing cartridge 52 Door for drum cartridge 52a Lever part 53 Spring 54 Retracting member 100 Image forming apparatus 101 Laser unit 102 Reflecting mirror 105 Recording paper cassette 106 Paper feed roller 110 Fixing device 111 Paper discharge roller 112 Paper discharge tray 113 Drum cartridge guide 113a Concavity 200 Developing device switching mechanism 201 Rotating shaft
A Drum cartridge
T transfer station
P chart paper
L light dy yellow developing device
dm Magenta developing device
dc cyan developer
db Black developer

Claims (3)

A drum cartridge that has at least an electrophotographic photosensitive drum and is detachable from the image forming apparatus; and a developing cartridge that is separate from the drum cartridge and has at least a developer carrier and is detachable from the image forming apparatus;
An openable and closable drum cartridge door that covers the attachment and detachment path of the drum cartridge;
An image forming apparatus having a mechanism for moving the developing cartridge in conjunction with opening and closing of the drum cartridge door;
When the drum cartridge door is opened by the moving mechanism, the developing cartridge is separated from the photosensitive drum, and conversely, when the drum cartridge door is closed, the developing cartridge approaches the photosensitive drum.
An image forming apparatus characterized by that. A developing cartridge door that covers the mounting path of the developing cartridge separately from the drum cartridge door;
The image forming apparatus according to claim 1, further comprising: a pressing unit that brings the developing cartridge close to the photosensitive drum at the developing cartridge door. The image forming apparatus according to claim 1, wherein the developing cartridge is plural and can form a color image.

Images