JP2002174938A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily replace a developing cartridge of a color image forming device of a simple constitution. SOLUTION: Pressing members 57a, 57b, 57c and 57d of a prescribed length are separately installed in the developing cartridges 24a, 24b, 24c and 24d, and also, each center of gravity is deviated to one side. Besides, a switching mechanism constituted of an operation lever 51, etc., provided with a supporting mechanism and a pressure part 54, stoppers 55a, 55b, 55c and 55d and an abutting member 58 are installed in the main body. And by rotating the operation lever 51 of the switching mechanism in a prescribed direction, all the developing cartridges in a 1st developing allowable state are put in a 2nd attachable/ detachable state, and also, by rotating the lever 51, all the developing cartridges are attached, and then, the cartridges in the 2nd state are put in the 1st developing allowable state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a copying machine,
The present invention relates to a color image forming apparatus having a plurality of photosensitive drums and a developing cartridge in a printer, a facsimile or the like.

[0002]

2. Description of the Related Art A conventional color image forming apparatus has a plurality of photosensitive drums for colorizing an image, and a charging device, an exposure device, a developing device, a transfer device, and a cleaning device are provided around the photosensitive drum. Are provided in this order, and each unit sequentially performs each processing to obtain an image reproduced corresponding to a color image. Such a device having a plurality of photosensitive drums and performing sequential processing is called a tandem type.

[0003] Specifically, a tandem type color image forming apparatus includes four magenta, cyan, yellow and black color image forming apparatuses.
In order to form an image corresponding to a color, four sets of image forming stations are provided. Each image forming station is provided with a photoconductor drum that is driven to rotate to form an image, and a charging device that uniformly charges the photoconductor drum around the photoconductor drum, and a photoconductor drum on the photoconductor drum. A developing device that develops the electrostatic latent image formed on the photosensitive drum, a transfer roller that transfers the developed toner image on the photosensitive drum to a recording sheet, and a cleaning device that removes toner remaining on the photosensitive drum. They are sequentially arranged along the rotation direction of the photosensitive drum.

[0004]

However, in the above-described color image forming apparatus, the developing device is a cartridge, and when a predetermined number (life cycle) of development is performed, the developing cartridge is replaced. Need to be done. Therefore, when replacing the developing cartridge of the conventional color image forming apparatus, it is necessary to remove and attach each of the developing cartridges provided separately for four colors. That is, since the pressing and separating operations of the respective developing cartridges are performed separately, there is a problem that the replacement operation is very troublesome and time-consuming.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a color printer having a simple structure and capable of easily replacing a developing cartridge. An object of the present invention is to provide an image forming apparatus.

[0006]

According to a first aspect of the present invention, a plurality of photosensitive drums for forming an image and a developing cartridge provided at a developing position corresponding to the photosensitive drum are provided. A first state in which the developing cartridge is provided with a pressing member having a predetermined length, and the pressing members connect the developing cartridges to each other to form a developable position; A switching mechanism is provided for releasing the connection by the member and switching to a second state in which each of the developing cartridges is in a detachable position separated from the photosensitive drum.

According to this configuration, all the developing cartridges in the first state can be moved to the second state separated from the photosensitive drum at a time, and the developing cartridge in the second state can be moved. The cartridge can be moved to the first state at a time, and replacement of the developing cartridge is facilitated.

According to a second aspect of the present invention, the center of gravity of the developing cartridge is set such that when the pressing member is connected or disconnected, the developing cartridge is rotated by its own weight in a direction away from the photosensitive drum. It is characterized by being.

According to this structure, a special mechanism for rotating the developing cartridge and a special operation are not required, the structure can be simplified, and the replacement of the developing cartridge is further facilitated.

According to a third aspect of the present invention, when the pressing member is attached to the developing cartridge via an elastic member and the connection of the pressing member is released, the developing cartridge is exposed to light by a restoring force of the elastic member. It is characterized in that it is configured to rotate and move in a direction away from the body drum.

According to this configuration, it is not necessary to take time and effort to rotate the developing cartridge, the replacement of the developing cartridge is made easier, and the operation for connecting by the pressing member can be performed smoothly.

A fourth aspect of the present invention is characterized in that a stopper for positioning the developing cartridge in the second state is provided.

According to this configuration, the developing cartridge can be restricted to the predetermined position in the second state, and the detachment becomes easy.

According to a fifth aspect of the present invention, the switching mechanism presses a developing cartridge placed on the most upstream side,
It is characterized by comprising an operation lever for switching the developing cartridge between the first state and the second state, and a supporting mechanism for rotatably and detachably supporting the developing cartridge.

According to this configuration, the developing cartridge can be rotatably and detachably supported with a simple configuration.

A sixth invention is characterized in that a rolling element is provided at the tip of the pressing portion of the operation lever.

According to this configuration, the pressing by the operating lever and the releasing operation thereof can be performed smoothly.

According to a seventh aspect of the present invention, the support mechanism includes a support shaft provided at a bottom portion of the developing cartridge and a support member rotatably supporting the support shaft. And is detachably attached to the support member and rotatably supported.

According to this configuration, according to this configuration, the developing cartridge can be rotatably and detachably supported with a simple configuration.

An eighth invention is characterized in that a lock mechanism is provided on the support shaft and the support member.

According to this configuration, the developing cartridge can be more securely mounted.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a tandem-type color copying machine will be described below with reference to the drawings. The present invention can be applied to a printer, a facsimile, and the like in addition to a color copying machine. FIG. 1 is a front layout diagram showing the overall schematic configuration of an embodiment of the present invention.

As shown in FIG. 1, a document table 11 on which a document to be read is placed is provided on the upper surface of the main body of the color copying machine, and the document table 11 is placed inside the body. An image reading unit 1 for reading an image of a document, an image forming unit 2 for forming a toner image corresponding to the document image, and a recording sheet serving as a recording medium is supplied to the image forming unit 2. A paper transport unit 3 for discharging the formed recording paper 31 is provided. Also, platen 1
An automatic document feeder (hereinafter, referred to as an ADF) for automatically feeding a document is mounted on the upper side of the printer 1 so as to be freely opened and closed.

The image reading section 1 is disposed below the document table 11 and reciprocates in parallel along the lower surface of the document table 11, a document scanning body 13, an optical lens 15, and a CCD line sensor as a photoelectric conversion element. ADF12
The image of the original sent to the original platen 11 from the original is read.

The paper transport section 3 is disposed below the image forming section 2 and includes a paper feed mechanism 32, registration rollers 33, driven rollers 34, a transfer transport belt 36, a drive roller 38, a discharge roller 39, and the like. The paper feed mechanism 32 separates the recording papers 31 stored in the paper feed cassette one by one and supplies them to the image forming unit 2. Then, the recording paper 31 separated one by one is conveyed to the image forming unit 2 with the timing controlled by a pair of registration rollers 33 disposed in front of the image forming unit 2.

The transfer conveyance belt 36 is disposed immediately below the image forming section 2, and has a driving roller 38 at both ends and a driven roller 34.
It is stretched so as to extend substantially in parallel between the two. The transfer transport belt 36 is frictionally driven by a drive roller 38, electrostatically attracts the recording paper 31 sent from the paper feed mechanism 32, and transports the recording paper 31 in the direction indicated by the solid line arrow in the drawing.

A fixing device 40 for fixing the toner image transferred and formed on the recording paper 31 is disposed downstream of the transfer conveyance belt 36. The recording paper 31 fixed by passing through the fixing device 40 is discharged onto a discharge tray 41 by a discharge roller 39.

The image forming section 2 is disposed between the image reading section 1 and the sheet transport section 3 and has four image forming stations 2a, 2b, 2c, 2d. Each of the four image forming stations 2a, 2b, 2c, 2d is arranged in order from the upstream side of the transport path of the recording paper 31, and has substantially the same configuration.

More specifically, a photosensitive drum 21a is rotatably provided in the image forming station 2a.
Around the photosensitive drum 21a, a charging device for uniformly charging the photosensitive drum 21a, a developing device for developing an electrostatic latent image formed on the photosensitive drum 21a, and a developed photosensitive drum 21a A transfer roller 22a for transferring the upper toner image onto the recording paper 31 and a cleaning device for removing toner remaining on the photosensitive drum 21a are sequentially arranged along the rotation direction of the photosensitive drum 21a. Note that a developing cartridge 24a is used as a developing device. The same applies to the other image forming stations 2b, 2c and 2d. A transfer roller 22b is provided corresponding to the photosensitive drum 21b, and a developing cartridge 24b is used as a developing device. A transfer roller 22c is provided corresponding to the photosensitive drum 21c, and a developing cartridge 24c is used as a developing device. Further, a transfer roller 22d is provided corresponding to the photosensitive drum 21d, and a developing cartridge 24d is used as a developing device.

A laser beam scanner unit 23a is disposed above the photosensitive drum 21a of the image forming station 2a. The laser beam scanner unit 23a includes a semiconductor laser device that emits dot light modulated according to image data, a polygon mirror (deflecting device) for deflecting a laser beam from the semiconductor laser device in the main scanning direction, and a polygon mirror. A lens and a mirror for imaging the laser beam deflected by the laser beam on the surface of the photosensitive drum 21a. The same applies to the other image forming stations 2b, 2c, and 2d. The image forming station 2b is provided with a laser beam scanner unit 23b, and the image forming station 2c is provided with a laser beam scanner unit 23c.
The image forming station 2d is provided with a laser beam scanner unit 23d.

A pixel signal corresponding to a black component image of a color original image is supplied to the laser beam scanner unit 23a.
A pixel signal corresponding to the cyan color component image of the color original image is supplied, and the laser beam scanner unit 23c
A pixel signal corresponding to the magenta component image of the color original image is supplied, and a pixel signal corresponding to the yellow component image of the color original image is supplied to the laser beam scanner unit 23d. Therefore, the photosensitive drums 21a, 21
On each of b, 21c and 21d, an electrostatic latent image corresponding to the color-converted document image information is formed.

The developing cartridge 24a contains black toner, the developing cartridge 24b contains cyan toner, the developing cartridge 24c contains magenta toner, and the developing cartridge 24d
Contains yellow toner, and the electrostatic latent images on the photosensitive drums 21a, 21b, 21c, and 21d are developed by the toners of these colors. Therefore, the document image information color-converted by the image forming unit 2 is reproduced as a toner image of each color. Photoconductor drums 21a, 21b, 21
Each of the toner images formed on c and 21d is sequentially transferred to the recording paper 31 conveyed by the transfer conveyance belt 36 by the action of the transfer rollers 22a, 22b, 22c and 22d.

In a position directly above the driving roller 38 between the image forming station 2d and the fixing device 40,
A static eliminator 25 is provided. An AC current for separating the recording sheet 31 electrostatically attracted to the transfer / transport belt 36 from the transfer / transport belt 36 is applied to the neutralizer 25, and when the image transfer by the image forming station 2d is completed, the AC current is applied. , The recording paper 31
The toner image is sent to the fixing device 40 where the toner image is fixed, and then discharged onto the paper discharge tray 41.

FIG. 2 shows the developing cartridges 24a, 24
FIG. 3 is a front layout diagram showing a schematic configuration around a portion where b, 24c, and 24d are arranged. FIG.
It is explanatory drawing which expanded the part of a. FIG. 4 is a top plan view showing a schematic configuration around a portion where the developing cartridges 24a, 24b, 24c, and 24d are provided. In FIGS. 2, 3 and 4, parts corresponding to those in FIG. 1 are denoted by the same reference numerals.

As shown in FIG. 3, the developing cartridge 24 includes a developing roller 61, a supply roller 62, a toner container 65 and the like corresponding to the developing area of the photosensitive drum 21a.
a is attached. In the toner container 65, a front plate F is disposed on the photosensitive drum 21a side, and a rear plate B is disposed on the upstream side remote from the photosensitive drum 21a. The rear side plate B is
It has a predetermined curved surface shape, and as shown in FIG. 2, when the operation lever 51 is operated, the pressing portion 54 moves smoothly. The other developing cartridges 24b, 24c, and 24d have the same configuration.
As shown in FIGS. 2 and 4, the developing cartridge 21a is mounted at the most upstream position on the transport path, the second developing cartridge 24b is mounted, the third developing cartridge 24c is mounted, and the developing cartridge 2
4d is attached. Developing cartridges 24a,
Each of 24b, 24c, and 24d can be in a state of contacting or approaching the photosensitive drums 21a, 21b, 21c, and 21d and a state of being separated from each other by a switching mechanism including a support mechanism and an operation lever 51 and the like. It is configured as follows.

More specifically, as shown in FIG. 3, the support mechanism in the switching mechanism is constituted by a support shaft 64 provided on the bottom of the developing cartridge 24a and serving as a rotation shaft, and a support member 59a provided on the main body side. It is configured. The support member 59a engages with the support shaft 64, and the developing cartridge 24a
Is rotatably supported. The other developing cartridge 2
4b, 24c, and 24d have the same configuration, and a supporting member 59b is provided corresponding to the developing cartridge 24b, and a supporting member 59c corresponding to the developing cartridge 24c.
Are provided, and a support member 59d is provided corresponding to the developing cartridge 24d.

The operating lever 51 has a substantially L-shape, and has a pressing portion 54 for pressing the rear plate B (see FIG. 4) of the developing cartridge 24a located on the most upstream side. Is provided so as to be rotatable around the fulcrum. A roller 53 is provided at the distal end of the pressing portion 54 provided on the operation lever 51, and is configured so that resistance due to friction during switching operation by the operation lever 51 is reduced.

Further, the developing cartridges 24a, 24
The pressing members 57a, 57 having a predetermined length are provided on the front side plate F of each of the toner storage portions 65 of the b, 24c, 24d.
b, 57c, 57d are elastic members 56a, 56b, 56
c, 56d, and the pressing member 57
The a, 57b, 57c, and 57d are configured such that, when a force is applied to their ends, the elastic members 56a, 56b, 56c, and 56d retract to a predetermined position while contracting.
In addition, the elastic force of the elastic members 56a, 56b, 56c, and 56d is set to be larger on the upstream side of the transport path. In addition, a contact member 58 with which the pressing member 57d of the developing cartridge 24d, which is the most downstream in the transport path, abuts is disposed at a predetermined position on the downstream side of the main body.

Accordingly, the pressing portion 54 of the operation lever 51
Pressing members 57a, 57b, 57c provided on each of the developing cartridges 24a, 24b, 24c, 24d,
The developing cartridges 24a, 24b, 24c and 24d are positioned at predetermined positions by 57d and a contact member 58 provided on the main body. In this positioned state, the developing roller 61 provided in the developing cartridge 24a is in a first developable first state as shown by a solid line in FIG. 3, that is, close to or in contact with the photosensitive drum 21a. Be in contact. Similarly, the developing roller 61 provided in each of the developing cartridges 24b, 24c, and 24d is in a predetermined first developable state, that is, close to or in contact with the photosensitive drums 21b, 21c, and 22d. State. In this state, the optical path of the laser beam from the laser beam scanner units 23a, 23b, 24c, 24d to the photosensitive drums 21a, 21b, 21c, 21d is secured as shown in FIG.

As shown in FIG. 3, the center of gravity of the developing cartridge 24a is set on the operation lever 51 side.
Similarly, the center of gravity of the developing cartridge 24b is set on the side of the developing cartridge 24a, the center of gravity of the developing cartridge 24c is set on the side of the developing cartridge 24b, and the center of gravity of the developing cartridge 24d is set on the side of the developing cartridge 24c. Therefore, the developing cartridge 24
When the operating lever 51 is rotated to release the connecting force, each of the members a, 24b, 24c, and 24d has a biased center of gravity and elastic members 56a, 56b, 56c, and 56d.
By using the restoring force, the photosensitive drums 21a, 21b, 21c, and 22d are rotated about the respective support shafts 64 as fulcrums (clockwise in FIG. 3).

Further, the developing cartridge 24a on the main body side
A stopper 55a is provided at a predetermined position below the nearby operation lever 51. This stopper 55a
Is located at a position where the developing cartridge 24a rotates clockwise, and the developing roller 61 is separated from the photosensitive drum 21a and can be pulled out in the axial direction. That is, as shown by a broken line in FIG. It is a state of. The same applies to other parts related to the developing cartridges 24b, 24c, and 24d. A stopper 55b is provided corresponding to the developing cartridge 24b, and a stopper 55c is provided corresponding to the developing cartridge 24c.
A stopper 55d is provided corresponding to.

The operation of each part when the developing cartridges 24a, 24b, 24c, 24d are replaced in the embodiment constructed as described above will be described in further detail. FIG. 5A shows the developing cartridges 24a, 24b,
It is explanatory drawing which shows the 2nd state in which 24c and 24d become detachable. FIG. 5B is an explanatory diagram illustrating a first state in which development is possible. In FIGS. 5A and 5B, portions corresponding to FIGS. 1, 2, 3, and 4 are:
The same reference numerals are given.

First, as shown in FIG. 5A, when the operation lever 51 is rotated in a counterclockwise direction (shown by a in the figure),
The pressing portion 54 of the operation lever 51 is connected to the developing cartridge 24a.
The developer cartridge 24a moves in a direction away from the rear side plate B, and the pressing of the developing cartridge 24a is released. Then, the force for connecting the developing cartridges 24a, 24b, 24c, and 24d does not work, so that the developing cartridges 24a,
Each of b, 24c, and 24d rotates clockwise (see a in the drawing) with the respective support shaft 64 as a fulcrum due to the rotation by its own weight and the restoring force of the elastic members 56a, 56b, 56c, and 56d.
1 to a4), the rotation starts to be started from the upstream side. Then, the developing cartridges 24a, 24b, 24
The second detachable second plates c and 24d are in contact with the main body side stoppers 55a, 55b, 55c and 55d, and the developing rollers 61 are separated from the photosensitive drums 21a, 21b, 21c and 21d. State. In this state, the developing cartridges 24a, 24b,
24c and 24d are respectively supported by support members 59a and 59d.
b, 59c, 59d, which can be drawn out in the longitudinal direction, and the used developing cartridges 24a, 24b, 2
4c and 24d are removed. Then, unused developing cartridges 24a, 24b, 24c, 24d are mounted.

Next, as shown in FIG. 5B, when the operating lever 51 is rotated clockwise (indicated by b in the figure), the pressing portion 54 of the operating lever 51 pushes the rear plate B of the developing cartridge 24a. And starts to rotate in the counterclockwise direction (indicated by b1 to b4 in the figure) sequentially from the upstream side. That is,
The pressing member 57a of the developing cartridge 24a presses the rear plate B of the developing cartridge 24b, whereby the pressing member 57b of the developing cartridge 24b
The pressing member 57c of the developing cartridge 24d presses the rear plate B of the developing cartridge 24d, whereby the pressing member 57d of the developing cartridge 24d presses the contact member 58 on the main body side.
Then, the developing cartridges 24a, 24b, 24c, 2
4d are positioned and the first developable first
It returns to the state of.

Therefore, the embodiment configured as described above has the following effects. The effect is that all the developing cartridges in the first state in which development can be performed are changed to the second state in which the developing cartridges can be detached and mounted by operating the lever once, and all the developing cartridges in the second state with the developing cartridge attached thereto are mounted. Is that it can be switched to the first state in which development can be performed by operating the lever once. Therefore, with a simple configuration, it is possible to extremely easily exchange a plurality of developing cartridges arranged in parallel.

Next, another embodiment will be described. In the above-described embodiment, the developing cartridges 24a,
The case where the positioning of the developing rollers 61 of 24b, 24c, 24d and the surfaces of the photosensitive drums 21a, 21b, 21c, 21d is defined by the lengths of the pressing members 57a, 57b, 57c, 57d has been described. A positioning member is provided at an end of the developing roller 61, and the positioning member and the photosensitive drums 21a, 21b, and 2 are disposed.
An arrangement may be made in which the end portions 1c and 21d are brought into contact with each other so that they can be aligned. With such a configuration, the design tolerance for the length of the pressing members 57a, 57b, 57c, and 57d can be increased, and the design can be easily performed.

The developing cartridges 24a, 24b,
Pressing members 57a, 57b provided on 24c, 24d,
Coloring corresponding to the toner color stored in the developing cartridge may be applied to 57c and 57d. By doing so, the color of the developing cartridge can be easily identified, and erroneous mounting in the replacement operation can be prevented.

The developing cartridges 24a, 24b,
The support mechanisms 24c and 24d can be constituted by conventionally known mechanisms. FIGS. 6 and 7 show specific examples in this case. As shown in FIG. 6, a lock portion 71 having a larger diameter than the support shaft 64 is formed on the near side (left side in the drawing) of the support shaft 64 provided at the bottom of the developing cartridge 24a in the insertion direction. Then, the support member 59
On the side a, as shown in FIG. 7, when the developing cartridge 24a is mounted on the support member 59a, a bearing 74 to which the tip of a support shaft 64 (shown by a broken line in the drawing) is engaged, and a guide for guiding the support shaft 64. The groove 73 and the lock portion 7 provided on the support shaft 64
1 and a lock hole 72 into which is inserted. With this configuration, when the developing cartridge 24a is mounted, the support shaft 64 can be easily inserted along the guide groove 73. After the insertion, the tip of the support shaft 64 is in contact with the bearing 74. The lock portion 71 of the support shaft 64 is fitted into the lock hole 72 and locked, and in this state,
The developing cartridge 24a can be rotatably supported. The other developing cartridges 24b, 24c, 2
4d has the same configuration, and the lock 64
Are formed, and the supporting members 59b, 59c, 59d on the main body side are formed.
Are provided with a bearing 74, a guide groove 73, and a lock hole 72, respectively.

It should be noted that the present invention is not limited to each of the above embodiments, and each embodiment can be appropriately modified within the scope of the technical idea of the present invention. Further, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, and shape suitable for carrying out the present invention. In each drawing, the same components are denoted by the same reference numerals.

[0050]

Therefore, according to the present invention, the following effects can be obtained. The effect is that all the developing cartridges in the first state in which development can be performed are changed to the second state in which the developing cartridges can be detached and mounted by operating the lever once, and all the developing cartridges in the second state with the developing cartridge attached thereto are mounted. Is that it can be switched to the first state in which development can be performed by operating the lever once. Therefore, with a simple configuration, it is possible to extremely easily exchange a plurality of developing cartridges arranged in parallel.

[Brief description of the drawings]

FIG. 1 is a front layout view showing the overall schematic configuration of an embodiment of the present invention.

FIG. 2 is a front layout diagram illustrating a schematic configuration around a location where a developing cartridge is provided according to the embodiment of the present invention.

FIG. 3 is an enlarged explanatory view of a developing cartridge according to an embodiment of the present invention.

FIG. 4 is a top plan view showing a schematic configuration around a portion where a developing cartridge is provided in one embodiment of the present invention.

FIG. 5 is an explanatory diagram used for describing the operation of the embodiment of the present invention.

FIG. 6 is an explanatory diagram used to describe a support mechanism of the developing cartridge.

FIG. 7 is an explanatory diagram used for describing a support mechanism of the developing cartridge.

[Explanation of symbols]

2a, 2b, 2c, 2d Image forming stations 21a, 21b, 21c, 21d Photoconductor drums 22a, 22b, 22c, 22d Transfer rollers 23a, 23b, 23c, 23d Laser beam scanner units 24a, 24b, 24c, 24d Developing cartridge 34 Driven roller 36 Transfer / transport belt 38 Drive roller 51 Operating lever 52 Lever shaft 53 Roller 54 Pressing portions 55a, 55b, 55c, 55d Stoppers 56a, 56b, 56c, 56d Elastic members 57a, 57b, 57c, 57d Pressing member 58 Contact member 59a , 59b, 59c, 59d Supporting member 61 Developing roller 62 Supply roller 64 Support shaft 65 Toner container 71 Lock portion 72 Lock hole 73 Guide groove 74 Bearing B Rear plate F Front plate

Claims (8)

[Claims] 1. A color image forming apparatus comprising: a plurality of photosensitive drums for forming an image; and a developing cartridge provided at a developing position corresponding to the photosensitive drum. A first state in which each of the developing cartridges is connected to the developing position by the pressing member, and the developing cartridge is separated from the photosensitive drum by releasing the connection by the pressing member. And a switching mechanism for switching to a second state in which the removable position can be set. 2. When the connection of the pressing member is released,
2. The center of gravity of the developing cartridge is set such that the developing cartridge rotates and moves in a direction away from the photosensitive drum by its own weight.
The color image forming apparatus as described in the above. 3. The developing cartridge is separated from the photosensitive drum by the restoring force of the elastic member when the pressing member is attached to the developing cartridge via an elastic member and the connection of the pressing member is released. The color image forming apparatus according to claim 1, wherein the color image forming apparatus is configured to rotate and move in a direction in which the color image is formed. 4. A color image forming apparatus according to claim 1, further comprising a stopper for positioning said developing cartridge in said second state. 5. A switching unit for switching a developing cartridge between the first state and the second state, wherein the switching mechanism presses a developing cartridge placed on the most upstream side, and an operating lever for switching the developing cartridge between the first state and the second state. 5. The color image forming apparatus according to claim 1, further comprising a support mechanism rotatably and detachably supported. 6. The color image forming apparatus according to claim 5, wherein a rolling element is provided at an end of the pressing portion of the operation lever. 7. The support mechanism includes a support shaft provided at a bottom portion of the developing cartridge, and a support member rotatably supporting the support shaft, and the developing cartridge supports the support via the support shaft. 6. The color image forming apparatus according to claim 5, wherein the color image forming apparatus is detachably attached to a member and rotatably supported. 8. The color image forming apparatus according to claim 7, wherein a lock mechanism is provided on the support shaft and the support member.