JPH11316480A - Electrophotographic color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain a satisfactory image by supporting a developing unit which is made nearer to and away from an image carrier at a proper position at all times, when an image is formed in an electrophotographic color image forming device, in which at least one of plural developing units is made nearer to and away from the image carrier. SOLUTION: An image forming device main body 10 is provided with recording medium feeding paths 62 and 65 from a front side, and image carriers 11 and 17 behind them and the plural developing units 15 and 16 on a rear side. Then, at least one of the plural developing units, for instance the black developing unit 16 is made freely turnable by centering a turn supporting point, such as a supporting shaft 85 supported by a side plate at the inside of the device main body 10, so as to be capable of taken or removed from the first image carrier 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color copying machine
The present invention can be applied to a color image forming apparatus that records a color image on a recording medium such as paper, such as a color facsimile / color printer and a multifunction peripheral thereof. In particular, the present invention relates to an electrophotographic color image forming apparatus that performs recording using an electrophotographic process such as charging, writing, development, transfer, and fixing.

[0002]

2. Description of the Related Art Conventionally, in this type of electrophotographic color image forming apparatus, a monochrome image is sequentially formed on a first image carrier by repeating charging, writing, development, transfer, cleaning, and the like. In some cases, the monochromatic images are sequentially transferred to form a composite color image on a second image carrier, and the color images are collectively transferred to record a color image on a recording medium.

In such a color image forming apparatus, not only a color image is recorded but also a monochrome image is frequently recorded. Therefore, the consumption amount of the black developer is much larger than the consumption amount of the color developer. More. Therefore, a black developing device for storing the black developer is provided separately from a color developing device for storing the other color developers, so that a large amount of the black developing agent can be stored, and the black developing device can be replaced independently with a new one. There is something that I did.

When a color image is recorded on a recording medium, for example, with the rotation of the first image carrier,
First, a color developing device at an upstream position forms a color monochromatic image on the first image carrier, and then a black developing device at a downstream position forms a black monochromatic image on the first image carrier. And

At this time, when a color monochromatic image is formed on the first image carrier, the black developing device is formed using a cam member so that the black developing device located at the downstream position does not disturb the image. When forming a black monochromatic image by sliding away from the first image carrier by sliding against the urging force, the black developing device was slid based on the urging force and approached to the first image carrier.

[0006]

However, if the black developing device is slid away from the first image carrier or moved closer to the first image carrier as described above, the sliding resistance is reduced due to the sliding resistance. The operation became unstable, the black developing device could not always be held at an appropriate position, and there was a problem that a good image could not be obtained stably.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic color image forming apparatus as described above, in which a developing unit is always kept at a proper position when an image is formed, and a good image is stably obtained. To be able to do it.

[0008]

For this reason, the invention according to claim 1 is, for example, as described in the following embodiments with reference to the drawings, from the front side of the image forming apparatus main body 10.
The recording medium transport paths 62 and 65, and the image carrier 11.1.
7. In an electrophotographic color image forming apparatus further including a plurality of developing devices 15 and 16 at the back thereof, at least one of the plurality of developing devices 15 and 16, for example, a black developing device 1
6 is rotatable about a rotation fulcrum such as a support shaft 85 so as to be able to approach or move away from the image carrier 11.

According to the first aspect of the present invention,
At least one developing device 16 is rotated about a rotation fulcrum. When developing is performed using the developing device 16, the developing device 16 approaches the image carrier 11, and when not performing development, moves away from the image carrier 11.

According to a second aspect of the present invention, in the electrophotographic color image forming apparatus according to the first aspect, for example, as in an embodiment described with reference to the following drawings, the inside of the image forming apparatus main body 10 is provided. A support shaft 85 is provided and the support shaft 85 is provided.
Is provided on the developing device 16 which is rotatable about the rotating fulcrum, and a fitting hole 93a is provided. Hole 9
A notch 93b that fits into the hole 3a or comes out of the fitting hole 93a is provided in the fitting hole 93a in the mounting / removing direction of the developing device 16.

[0011] In the invention according to claim 2,
When taking out the developing device 16 rotatable about the rotation fulcrum from the image forming apparatus main body 10, the supporting shaft 85 fitted in the fitting hole 93 a is pulled out through the notch 93 b, and the developing device is removed. Pull out 16. When the developing device 16 is mounted in the image forming apparatus main body 10, the support shaft 85 passes through the notch 93b, is fitted into the fitting hole 93a, and the developing device 16 is inserted.

According to a third aspect of the present invention, in the electrophotographic color image forming apparatus according to the first or second aspect,
For example, as in an embodiment described with reference to the following drawings, a developing device 1 that is rotatable around the pivot point.
6 is provided on one of the upper and lower sides, and the other is
6 is provided with an action lever 88 for rotating the same.

In the invention according to claim 3,
The operating lever 88 is driven to rotate the developing device 16 which is rotatable about the rotation fulcrum.

[0014] The invention described in claim 4 is the first or second invention.
Alternatively, in the electrophotographic color image forming apparatus described in item 3, for example, as in an embodiment described with reference to the following drawings, when the image forming apparatus is approached to the image carrier 11, the image forming apparatus is rotatable about the rotation fulcrum. A positioning member 86 that determines the rotation position of the developing device 16 is supported by the same side plate that supports an image forming system in the image forming apparatus main body 10 together with the rotation fulcrum such as the support shaft 85. , Characterized in that.

In the invention according to claim 4,
When developing is performed by the developing device 16 that is rotatable around the pivot point, the pivot position of the developing device is determined by the pivot member and the positioning member 86 supported by the same side plate.

According to a fifth aspect of the present invention, in the electrophotographic color image forming apparatus according to the third or fourth aspect,
For example, as in an embodiment described with reference to the following drawings, the operating lever 88 is also used as a guide for attaching and detaching the developing device 16 that is rotatable about the pivot point. Features.

Further, in the invention according to claim 5,
When attaching / detaching the developing device 16 which is rotatable about a pivot point, the operation lever 88 is also used as a guide.

According to a sixth aspect of the present invention, there is provided the electrophotographic color image forming apparatus according to the first aspect, wherein the plurality of developing units 15 and 16 are provided as in an embodiment described with reference to the following drawings. A black developing device 16 for storing a black developer and a color developing device 15 for storing a plurality of color developers are provided, and the black developing device 16 is installed on the color developing device 15 to perform black development. The color developing device 15 is also used as a guide when the black developing device 16 is attached and detached, while the device 16 is rotatable about the pivot point.

In the invention according to claim 6,
When attaching / detaching the black developing device 16 which is rotatable about a pivot point, the color developing device 15 is also used as a guide.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall schematic configuration of an internal mechanism in an electrophotographic color laser printer according to the present invention. FIG. 2 shows a partially enlarged configuration around the first image bearing member and the two developing devices in the use state of the black developing device.

Reference numeral 10 in the drawing denotes a printer main body. An image forming system is provided in the printer apparatus main body 10, and an endless belt-shaped first image carrier 11 is provided at a position slightly closer to the front (rightward in the figure). The first image carrier 11 is
As shown in FIG. 2, the driving roller 12 and the driven roller 13
I will hang over it.

Around the first image carrier 11, a charger 14 provided thereunder provides a first image carrier 1.
1 in the transport direction a shown by an arrow in FIG.
5, a black developing device 16, an endless belt-shaped second image carrier 17, a cleaning device 18, and the like. A laser writer 19 is provided below the color developing device 15.

The color developing device 15 is, as shown in FIG.
In a cylindrical case 22 having a plurality of guide ribs 22a,
A support frame 24 is provided supported by the center shaft 23. In the supporting frame 24, a developing device 25 containing a yellow developer and a developing device 2 containing a magenta developer, respectively.
5 and a developing device 25 containing cyan developer are attached. The support frame 24 is centered on the center axis 23.
To rotate a developing roller 30 described later of each developing device 25,
The first image carrier 11 can be sequentially opposed.

As can be seen from FIG.
A first developer conveying member 27, a second developer conveying member 28, a supply roller 29, and a developing roller 30 are provided in parallel with each other. In FIG. 2, one developing unit 25 is used.
Only the inside is shown, and the other developing units 25 are omitted because they have the same configuration.

At one end of such a color developing device 15, as shown in FIG. 3, a fan-shaped developer accommodating portion 31 for each color is provided so as to be combined with the whole circular shape. Outside the developer storage portions 31
The developer cartridge 32 for replenishing the developer is detachably attached.

As shown in FIG. 2, the black developing device 16 accommodates a black developer and is set on the color developing device 15. In the developing case 34, agitators 35 and 36, a supply roller 37 and a developing roller 38 are provided. Etc.

The second image carrier 17 is in the form of an endless belt and extends between a driving roller 40 and a driven roller 41.
A part thereof contacts the first image carrier 11. A transfer device 42 is provided inside the contact position. Then, the transfer roller 44 of the composite image transfer device 43 is pressed against the outer periphery of the drive roller 40 from the right side, and the cleaning member 46 of the cleaning device 45 is pressed from the left side.

The transfer roller 44 and the cleaning member 46 are movable by a contact / separation mechanism (not shown), and are appropriately brought into contact with and separated from the second image carrier 17 during recording.

The cleaning device 18 presses the cleaning member 48 against the outer periphery of the drive roller 12 of the first image carrier 11. Then, the residual toner on the first image carrier 11 after the image transfer is removed by the cleaning member 48, and is collected and stored inside.

A laser writer 19 irradiates a laser beam L based on the write information, performs writing at an image writing position provided on the outer periphery of the drive roller 12, and forms an electrostatic latent image on the first image carrier 11. I do.

The printer main body 10 also includes a fixing device 50 above the black developing device 16, a discharge roller pair 51 on the left side of the fixing device 50, and a printer main body 10 on the left side. A discharge stack unit 52 is provided above. The fixing device 50 includes a fixing roller 5 having a built-in heater.
3 and a pressure roller 54 pressed against the fixing roller 53
And an oil supply mechanism 55 for applying oil to the peripheral surface of the fixing roller 53.

Further, although not shown, the printer device main body 10 further includes, for example, an electric device on the left side of the color developing device 15 and a ventilation fan. A paper cassette 57 containing the paper P is provided at the bottom so as to be freely taken in and out.

When recording is performed by using the printer shown in the figure, the paper P in the paper cassette 57 is fed by rotating the paper feed roller 60, and is conveyed through the recording medium conveyance path 62 by the conveyance roller pair 61. To stop against the pair of registration rollers 63.

At the same time, the first image carrier 11 is
And transports the second image carrier 17 in the transport direction b. First, with the transport of the first image carrier 11, the surface thereof is uniformly charged by the charger 14, and then the first image carrier 11 is charged.
A laser writer 19 irradiates a laser beam L based on the color writing information to form a first color electrostatic latent image on the first image carrier 11.

Then, at the position of the color developing device 15, the first developing device 25 moved to the developing position in contact with the first image carrier 11 adheres the first color toner to develop the electrostatic latent image. Then, the visible image is once transferred onto the second image carrier 17 by the transfer device 42. After the image transfer, the residual toner of the first color remaining on the first image carrier 11 is removed by the cleaning member 48 of the cleaning device 18.

Thereafter, when forming images of the second color and the third color, laser writing is similarly performed on the basis of the respective writing information to form respective electrostatic latent images, and the second and third colors are formed. Is moved to a developing position in contact with the first image carrier 11 to develop an electrostatic latent image, and these visible images are respectively transferred onto the second image carrier 17 to transfer the image. Later first
Of the image carrier 11 is cleaned.

When a black developer is used, similarly, an electrostatic latent image is formed by performing laser writing based on the writing information, and the developing roller 38 of the black developing device 16 is moved to the first position.
To contact the image carrier 11 to develop the electrostatic latent image, transfer the visible image onto the second image carrier 17, and transfer the first image after the image transfer.
Of the image carrier 11 is cleaned.

After each cleaning of the first image carrier 11, the surface thereof is neutralized by, for example, a neutralizer (not shown) to prepare for the next writing.

After the composite color image is formed on the second image carrier 17 as described above, the transfer roller 44 of the composite image transfer unit 43 and the cleaning member 46 of the cleaning unit 45 are moved to move the second image. While contacting the carrier 17, the paper P
Is transported between the transfer roller 44 and the second image carrier 17.
Then, the composite color image on the second image carrier 17 is transferred to the lower surface of the sheet P by the transfer roller 44.

After the image transfer, the sheet P is conveyed between the fixing roller 53 and the pressure roller 54 through the recording medium conveying path 65 with the recording surface facing down. Then, heat and pressure are applied between the rollers to fix the transferred image, and after the fixing, the sheet is discharged from the sheet discharge port 66 onto the sheet discharge stack section 52 by the sheet discharge roller pair 51 and is sequentially stacked.

On the other hand, after the image is transferred onto the second image carrier 17, the toner remaining on the second image carrier 17 is removed by the cleaning member 46 of the cleaning device 45. Then, the collected toner is conveyed toward the cleaning device 18. Then, the toner is stored in the waste toner tank 68 together with the toner collected by the cleaning device 18.

In the illustrated color laser printer, the recording medium transport paths 62.6
5, when the paper P is jammed in the recording medium transport paths 62 and 65, the front cover 70 provided on the front side of the apparatus main body 10 is attached to the mounting shaft 71 as shown in FIG.
And the recording medium transport paths 62 and 65
To release. Then, the front cover 70 is biased by, for example, a spring (not shown) and held at the open position. The front cover 70 includes one roller 61 a of the above-described conveying roller pair 61, a pair of registration rollers 63,
3 and the like.

As shown in FIG. 5, the mounting shaft 71 penetrates the boss 72a and is supported by the side plate 72.
The arm 70a extends from the base of the arm 70a through the distal end hole 70b, and the other end passes through the engaging hole 73a of the intermediate frame 73. The side plates 72 are provided on the left and right sides of the apparatus main body 10 so as to face each other, and between the image carriers 11 and 17 and the developing devices 15 and
16 and a member for supporting an image forming system such as the cleaning units 18 and 45.

As shown in FIG. 6, the above-described engaging holes 73a are formed in the intermediate frames 73 provided on the left and right, respectively.
In addition, a bearing hole 73b is provided thereon, and a first engaging concave portion 73c and a second engaging concave portion 73d are provided adjacent to the peripheral edge. Further, guide grooves 73e are provided on the inner surface so as to face each other.

The left and right intermediate frames 73
Are connected to both ends of the transport guide plate 75 so as not to be twisted by the transport guide plate 75 which also serves as a reinforcing member. Further, bearings 77 are provided in the bearing holes 73b by being urged by springs 76, respectively, and the roller shaft of the other roller 61b of the transport roller pair 61 is rotatably supported between the bearings 77. In the state shown in FIG. 1, the other roller 61b is pressed against the one roller 61a by being urged by a spring 76.

As shown in FIG. 6, between the intermediate frames 73, the left and right guide projections 81a are fitted into the guide grooves 73e from above, and the process cartridge 80 is inserted by being inserted into the transport guide plate 75. .

The process cartridge 80 collectively accommodates the above-described first image carrier 11, charging device 14, second image carrier 17, transfer device 42, cleaning devices 18 and 45, etc., in a cartridge case 81. I do. On the left and right sides of the cartridge case 81, a guide recess 81b is provided along with the guide protrusion 81a.

Normally, as shown in FIG. 7A, the distal end of a leaf spring 83 fixed in the apparatus main body 10 is pressed against the bottom edge 73f of the intermediate frame 73 and stored in the transport guide plate 75. 1 and 4, the process cartridge 80 is held in the apparatus main body 10 in a state where the process cartridge 80 is slightly moved backward.

However, when the process cartridge 80 is to be replaced, repaired, cleaned, or the like, the process cartridge 80 housed in the transport guide plate 75 is put on the mounting shaft 71 together with the intermediate frame 73 by putting a hand on the handle recess 81b. The plate spring 83 is rotated as a center to the position shown in FIG.
Is engaged with the first engaging concave portion 73c of the intermediate frame 73, and the process cartridge 80 is held in a substantially upright state as shown in FIG.

Then, in this state, the left and right hand recesses 8 are formed.
1b, the process cartridge 80 provided at the back of the recording medium transport path 62 is attached and detached.

At this time, if the position of the center of gravity of the process cartridge 80 is set on the vertical line of the mounting shaft 71, the elastic force of the leaf spring 83 is reduced, and
Can be improved.

When the process cartridge 80 is housed in the transport guide plate 75, the process cartridge 80 is further rotated around the mounting shaft 71 to the position shown in FIG.
Can be engaged with the second engaging concave portion 73d of the intermediate frame 73, fall down to the near side in the apparatus main body 10 as shown in FIG. 9, and can be held on the open front cover 70. it can.

Then, as shown by an arrow in the figure, the waste toner tank 68 can be taken out above, and
The color developing device 15 and the black developing device 16 provided on the back side of the process cartridge 80 can be taken out to the front side.

As shown in FIG. 10, the apparatus main body 10 is supported by the above-mentioned side plate for supporting the image forming system.
A support shaft 85 is provided on the left and right sides on the front side, a shaft-shaped positioning member 86 is provided on the lower left and right sides of the back side, and a lever shaft 87 is provided in parallel with the support shaft 85 on the back side. Two action levers 88 extending toward the front side are attached to the lever shaft 87 so as to be separated to the left and right, and the base end of a bracket 89 is attached to one end. The tip of the bracket 89 comes into contact with the peripheral surface of the eccentric cam 90. The compression lever 91 biases the compression lever 91 from above to a position slightly behind the support shaft 85 to push the lever 9.
2 is provided.

On the other hand, the black developing device 16 having a slightly
On the left and right sides of the front side, a resin arm 9 faces upward from the top.
Extend 3 At the tip of the arm 93, a fitting hole 93a into which the support shaft 85 fits without loosening is provided. Fitting hole 93a
Is provided with a notch 93b facing backward, through which the support shaft 85 finally passes when a strong force is applied.

When the black developing device 16 is mounted, the front cover 70 is opened and the process cartridge 8
11, the black developing device 16 is inserted horizontally from the front side as shown in FIG. 11, and is placed on the color developing device 15 under the support shaft 85, and the black developing device 16 is mounted on the above-described guide rib 22a. The push lever 92 is pushed up while pushing up the pressing lever 92 against the compression spring 91, and then the support shaft 85 is inserted into the fitting hole 93a through the notch 93b. Inset. Thereafter, the process cartridge 80 is again pushed down to the rear side, and the front cover 70 is closed to bring the state shown in FIG.

When the black developing device 16 is used, the eccentric cam 90 is rotated by a driving source (not shown) to rotate the bracket 89, and the operation lever 88 is pivoted about the lever shaft 87 in the figure. It rotates clockwise, the black developing device 16 rotates about the support shaft 85 as a rotation fulcrum, approaches the first image carrier 11, and finally contacts the positioning member 86 to actuate the operating lever 8.
8 is separated from the black developing device 16. Thereby, as shown in FIG. 2, the developing roller 38 is brought into contact with the first image carrier 11, and is pressed from above by the pressing lever 92 based on the urging force of the compression spring 91 to determine its rotational position.

Thereafter, when the use of the black developing device 16 is finished, the eccentric cam 90 is rotated by a driving source (not shown) to rotate the bracket 89, and the operating lever 88 is turned around the lever shaft 87 in the drawing. It rotates clockwise, contacts the black developing device 16, rotates it around the support shaft 85 as a rotation fulcrum, and moves away from the first image carrier 11 while pushing up the pressing lever 92 against the compression spring 91. Then, it returns to the state shown in FIG.

When taking out the black developing device 16, from the state shown in FIG. 12, the front cover 70 is opened and the process cartridge 80 is moved down to the front side to obtain the state shown in FIG. Then, the black developing device 16 is pulled out to the front side by holding a handle (not shown), and the support shaft 85 passes through the notch 93b and is pulled out from the fitting hole 93a.

In the illustrated color laser printer, when the developing units 15 and 16 are to be attached / detached, it is necessary to open the front cover 70 and then lower the process cartridge 80 to the front side to take out the process cartridge 80 from the apparatus main body 10 once. Therefore, the operability of attaching and detaching the developing units 15 and 16 can be improved.

In the illustrated color laser printer, endless belt-shaped image carriers 11 and 17 are used, but drum-shaped ones can also be used. For example, when a drum-shaped first image carrier 11 is used, the first image carrier 11 can be made rigid, and during development, the developing roller 38 is connected to the first image carrier 11.
To determine the rotational position of the black developing device 16,
The positioning member 86 can be dispensed with.

[0063]

According to the present invention, a recording medium transport path, an image carrier in the back, and a plurality of developing devices in the back are provided from the front side of the image forming apparatus main body. By opening the front side of the main body of the apparatus, the recording medium transport path is opened to enable the removal of jammed paper, and the removal of the image carrier and the developing unit. Therefore, it is not necessary to secure an operation space for maintenance, and the installation space can be reduced.

Further, since the jam processing can be performed without taking out the image forming units such as the image carrier, the developing device and the cleaning device, the operability of the jam processing is improved, and the toner scattering at the time of the jam processing is improved. The possibility of occurrence can be eliminated.

Further, the developing device is rotated about a pivot point to approach the developing device, and moves away when the developing process is not performed. Therefore, when using the developing device, the developing device is rotated to approach the image carrier. While the toner image can be formed on the image carrier, when it is not used, the toner image is rotated and moved away from the image carrier so as not to disturb the toner image formed on the image carrier by another developing device. Can be

As compared with the conventional case of sliding closer or farther away, the sliding resistance can be reduced and the operation stability can be improved.

According to the second aspect of the present invention, when the developing device rotatable about the rotation fulcrum is taken out of the image forming apparatus main body, the support shaft fitted in the fitting hole is cut off. When pulling out through the notch and mounting it in the main body of the device, on the contrary, the support shaft only needs to be inserted into the fitting hole through the notch. Can be.

According to the third aspect of the present invention, a rotating fulcrum is provided on one of upper and lower sides of a developing device which is rotatable about a rotating fulcrum, and an action lever for rotating the developing device is provided on the other. Since the developing device is rotated by the action lever, the developing device can be easily rotated with a simple configuration, and can be moved in and out in the horizontal direction, so that the operability of attaching and detaching the developing device can be improved.

According to the fourth aspect of the present invention, the rotation fulcrum and the positioning member are supported by the same side plate supporting the image forming system in the image forming apparatus main body, and the developing fulcrum and the positioning member are developed by the rotation fulcrum and the positioning member. To determine the rotation position of the developing device when performing
By improving the positional accuracy of the developing device with respect to other image forming systems, particularly the image carrier, it is possible to form a good image without banding or the like.

According to the fifth aspect of the present invention, when the developing device which is rotatable about the rotation fulcrum is attached and detached, the operating lever is also used as a guide, and according to the sixth aspect of the present invention. For example, since the color developing device is also used as a guide, it is possible to accurately guide the detachable developing device without providing a dedicated guide member, thereby preventing damage to the image carrier and the developing roller.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram of an internal mechanism in an electrophotographic color laser printer according to the present invention.

FIG. 2 is a partially enlarged configuration diagram around a first image carrier and two developing devices in a use state of the black developing device.

FIG. 3 is a schematic perspective view of a color developing device used in the color laser printer.

FIG. 4 is an overall schematic configuration diagram showing the color laser printer with a front cover opened.

FIG. 5 is an exploded perspective view of a pivot point portion of the front cover.

FIG. 6 is an exploded explanatory view of a process cartridge mounting portion in the color laser printer.

FIGS. 7A and 7B are explanatory diagrams of the operation of the process cartridge mounting portion, in which FIG. 7A shows a use state, FIG. 7B shows a take-out state, and FIG. 7C shows a retracted state when the developing device is replaced.

FIG. 8 is an overall schematic configuration diagram showing the color laser printer with a process cartridge attached and detached.

FIG. 9 is an overall schematic configuration diagram showing the developing device in a detached state.

FIG. 10 is a perspective view of a black developing device mounting portion in the color laser printer.

FIG. 11 is an explanatory side view showing a state where the black developing device is attached.

FIG. 12 is an explanatory side view showing a state after the attachment.

[Explanation of symbols]

 Reference Signs List 10 apparatus main body 11 first image carrier 15 color developing device 16 black developing device 17 second image carrier 62 recording medium transport path 65 recording medium transport path 85 support shaft (rotation fulcrum) 86 positioning member 88 operating lever 93a Fitting hole 93b Notch

Claims (6)

[Claims] 1. An electrophotographic color image forming apparatus comprising a recording medium conveying path, an image carrier in the back, and a plurality of developing devices in the back, from the front side of the image forming apparatus main body.
An electrophotographic color image forming apparatus, wherein at least one of the plurality of developing devices is rotatable about a rotation fulcrum so as to be able to approach or move away from the image carrier. 2. A fitting shaft is provided in the image forming apparatus main body, and the support shaft is used as the rotation fulcrum. On the other hand, a fitting hole is provided in a developing device which is rotatable about the rotation fulcrum. 2. A notch provided in the fitting hole in the attaching / detaching direction of the developing device, wherein the notch which the support shaft passes through and which fits into or comes out of the fitting hole when the developing device is attached / detached. 2. The electrophotographic color image forming apparatus according to 1. 3. A developing device which is rotatable around said pivot point, said pivot point being provided on one of upper and lower sides, and an operating lever for rotating said developer unit is provided on the other side. Or the electrophotographic color image forming apparatus according to 2. 4. A positioning member that determines a rotation position by applying a developing device that is rotatable around the rotation fulcrum when approaching the image carrier, together with the rotation fulcrum,
4. The electrophotographic color image forming apparatus according to claim 1, wherein the electrophotographic color image forming apparatus is supported by the same side plate supporting an image forming system in the image forming apparatus main body. 5. The electrophotographic color image according to claim 3, wherein the action lever is also used as a guide for attaching and detaching a developing device that is rotatable about the rotation fulcrum. Forming equipment. 6. A black developing device for storing a black developer and a color developing device for storing a plurality of color developers as the plurality of developing devices, and the black developing device is provided on the color developing device. The black developing device is installed so as to be rotatable around the pivot point, and the color developing device is also used as a guide for attaching and detaching the black developing device.
An electrophotographic color image forming apparatus according to claim 1.