JPH10153898A - Multicolor image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the manufacture, assembly and maintenance of a multicolor image forming device extremely easy and to prevent an image forming device from being made large-sized by using an intermediate transfer belt. SOLUTION: This multicolor image forming device possesses the intermediate transfer belt where a toner image on a photoreceptive drum is transferred and a transferring means transferring the toner image on the intermediate transfer belt on transfer paper. In this case, a device possesses first and second image forming means 1 and II freely attachably/detachably arranged with an interval to each other along the intermediate transfer belt 10 and having the same consitution, and a first image forming unit possesses one photoreceptive drum 15 and a developing unit 18 developing an electrostatic latent image on the photoreceptive drum with black toner, and a second image forming unit possesses one photoreceptive drum 25 and the developing unit 28 developing the electrostatic latent image on the photoreceptive drum with color toner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for temporarily transferring a toner image of a plurality of colors formed on an image carrier such as a photosensitive drum to an intermediate transfer belt, and transferring the transferred toner image on the intermediate transfer belt. The present invention relates to a multicolor / multicolor image forming apparatus for transferring an image to a transfer paper.

[0002]

2. Description of the Related Art As a multi-color image forming apparatus, a toner image obtained by developing an electrostatic latent image on a photosensitive drum by four developing devices arranged around a part of one photosensitive drum is obtained. Is temporarily transferred to an intermediate transfer belt and a toner image on the intermediate transfer belt is transferred to transfer paper (Japanese Patent Application Laid-Open No. 8-160597), or a plurality of transfer belts are supported on a transfer belt that supports and transports the transfer paper. Color image forming apparatus having a plurality of image forming means arranged side by side (JP-A-2-122)
No. 73, FIG. 6) is known.

[0003]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. 8-16069
Since the four developing devices of the color image forming apparatus described in Japanese Patent Application Laid-Open No. H07-214,197 are arranged on a part of the periphery of the photosensitive drum, even if each developing device has the same configuration, the attitude with respect to the photosensitive drum is changed. Since they are different from each other, there is a problem that they lack compatibility and cause inconvenience. A color image forming apparatus in which a plurality of image forming means are arranged side by side on a transfer belt that supports and conveys the transfer paper not only requires a means for supporting the transfer paper on the transfer belt, but also requires a length of the transfer belt. There is a problem that only transfer paper of a size corresponding to the size can be used.

[0004]

According to the first aspect of the present invention,
In the multicolor image forming apparatus, an intermediate transfer belt on which the toner image on the image carrier is transferred, and the multicolor image forming apparatus for transferring the toner image on the intermediate transfer belt to transfer paper by a transfer means, The image forming apparatus includes at least two image forming units that are arranged at regular intervals along the same moving surface of the belt. The first image forming unit includes an image carrier and an electrostatic latent image on the image carrier. Developing means for developing with one color developer, wherein the second image forming means
And a developing means for developing with a developer of a different color from the developer of the first image forming means.

According to a second aspect of the present invention, in the multicolor image forming apparatus according to the first aspect, the developing means of the first image forming means or the second image forming means is a developing means of black.

According to a third aspect of the present invention, there is provided an intermediate transfer belt on which a toner image on an image carrier is transferred, and a multicolor image forming apparatus for transferring the toner image on the intermediate transfer belt to transfer paper by transfer means. And three image forming means units arranged at regular intervals along the same moving surface of the intermediate transfer belt, and the first image forming means
One image carrier and developing means for developing the electrostatic latent image on the image carrier in black, and the second image forming means
Three image carriers and developing means for developing the electrostatic latent image on the image carriers with an A color developer other than black.
Is characterized by having one image carrier and developing means for developing the electrostatic latent image on the image carrier with a developer of B color other than black and A color.

According to a fourth aspect of the present invention, there is provided an intermediate transfer belt on which a toner image on an image carrier is transferred, and a multicolor image forming apparatus for transferring the toner image on the intermediate transfer belt to transfer paper by a transfer means. And three image forming means units arranged at regular intervals along the same moving surface of the intermediate transfer belt, and the first image forming means
A developing device for developing the electrostatic latent image on the image bearing member with a developer of color A other than black;
Image forming means comprises one image carrier and developing means for developing the electrostatic latent image on the image carrier with a developer of B color other than black, and the third image forming means comprises one image carrier. The image forming apparatus is characterized by comprising a carrier and developing means for developing the electrostatic latent image on the image carrier with a C color developer other than black.

According to a fifth aspect of the present invention, there is provided an intermediate transfer belt on which a toner image on an image carrier is transferred, and a multicolor image forming apparatus for transferring the toner image on the intermediate transfer belt to transfer paper by transfer means. And four image forming means arranged at regular intervals along the same moving surface of the intermediate transfer belt, wherein the first image forming means comprises one image carrier and a static member on the image carrier. Developing means for developing the electrostatic latent image in black, wherein the second image forming means forms one image carrier and the electrostatic latent image on the image carrier out of three primary colors of A, B and C Developing means for developing with an A color developer, wherein the third image forming means converts one image carrier and the electrostatic latent image on the image carrier into three primary colors of A, B, and C. Developing means for developing with the developer of B color, Wherein the developing means comprises one image carrier and developing means for developing the electrostatic latent image on the image carrier with a developer of C color of the three primary colors of A, B and C. And

[0009] The invention according to claim 6 is based on claims 1, 2,
In the multicolor image forming apparatus described in 3, 4 or 5, the image carrier is a drum-shaped or belt-shaped photoconductor.

[0010] The invention according to claim 7 is based on claims 1 and 2,
3. The multicolor image forming apparatus according to 3, 4, 5, or 6,
The image carrier is a drum-shaped or belt-shaped photoconductor.

[0011] The invention according to claim 8 is the invention according to claims 1, 2,
3. The multicolor image forming apparatus according to 3, 4, 5, or 6,
Each image forming means is detachable from the apparatus main body.

The ninth aspect of the present invention is the first aspect of the present invention.
The multicolor image forming apparatus described in 3, 4, 5, 6, 7 or 8 is characterized in that each image forming means has the same configuration as each other.

The invention according to claim 10 is the first or second invention.
In the multicolor image forming apparatus described in 3, 4, 5, 6, 7, 8 or 9, each image forming means is arranged in the same posture and along the moving direction of the intermediate transfer belt on the same moving plane. It is characterized by.

The eleventh aspect of the present invention is the first aspect of the present invention.
The multicolor image forming apparatus described in 3, 4, 5, 6, 7, 8, 9 or 10 is characterized in that each image forming means is unitized.

According to a twelfth aspect of the present invention, in the multicolor image forming apparatus of the second, third or fifth aspect, the developing means for developing in black has a larger toner capacity than the developing means for developing in other colors. It is characterized by the following.

According to a thirteenth aspect of the present invention, there is provided an intermediate transfer belt on which a toner image on an image carrier is transferred, and a multicolor image forming apparatus for transferring the toner image on the intermediate transfer belt to transfer paper by a transfer means. Has at least two image forming units arranged at a constant interval along the same moving surface of the intermediate transfer belt, and each image forming unit has
An image carrier, charging means for uniformly charging the surface of the image carrier, means for forming an electrostatic latent image on the charged image carrier, and an electrostatic latent image on the image carrier. An image forming unit comprising a developing unit for developing and a cleaning unit for removing the toner on the image carrier after transferring the toner image on the image carrier to the intermediate transfer belt; Have the same configuration, are arranged in the same posture, along the direction of movement of the intermediate transfer belt on the same plane of movement, and are detachable from the apparatus main body.

According to a fourteenth aspect of the present invention, in the multicolor image forming apparatus according to the thirteenth aspect, the image bearing member is a drum-shaped or endless belt-shaped photosensitive member, and the image forming units are compatible with each other. It is characterized by the following.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A multicolor image forming apparatus according to the present invention has an intermediate transfer belt on which a toner image on an image carrier is transferred, and at least a first transfer belt extends along the same moving surface of the intermediate transfer belt. Two image forming units, an image forming unit and a second image forming unit, are arranged at a fixed interval. 2
When one image forming unit is provided, the first image forming unit includes one image carrier and a developing unit that develops the electrostatic latent image on the image carrier with a developer of one color, Second
The image forming means includes one image carrier and a developing means for developing with a developer of a different color from the developer of the first image forming means. The developing means of the first image forming means or the second image forming means may be black developing means. In this case, a part of the text in black characters may be replaced with a character other than black characters, for example, red characters, a red underline may be provided at a key point in the text in black characters,
A red sign or a red pattern can be given in the right place.

When three image forming means are employed, the developing means of the first image forming means is a developing means for developing in black, and the developing means of the second image forming means is a developing means of A color other than black. The developing means of the third image forming means may be a developing means of developing with a developer of B color other than black and A color. In this case, part of the text in black characters is replaced with characters other than black characters, for example, red or blue characters, red or blue underlining is applied to key parts of text in black characters, or red or blue Signs, patterns, etc. can be given.

When four image forming means are employed, the developing means of the first image forming means is a developing means for developing with a black developer, and the developing means of the second image forming means are A,
A developing means for developing with a developer of A color of the three primary colors consisting of B and C colors, a developing means of the third image forming means as a developing means for developing with a developer of B color, and a fourth image forming means May be used as a developing unit for developing with a C color developer. In this case, not only multicolor copying but also color copying or color printing can be obtained.

Each image forming means is unitized,
The intermediate transfer belts have the same configuration, are arranged in the same posture, along the moving direction of the same moving plane of the intermediate transfer belt, are detachable from the apparatus main body, and are interchangeable with each other. Therefore, an image forming unit including a developing unit having a developer of a desired color can be selectively adopted as needed.

[0022]

In FIG. 1 showing a first embodiment, an intermediate transfer belt 10 is stretched between a driving roller 11 and a driven roller 12 so that the intermediate transfer belt 10 travels in the direction of arrow a by the driving roller 11. Driven. Intermediate transfer belt 10
Has an optimal tension given by the tension roller 13. On the lower running surface of the intermediate transfer belt 10, a first image forming unit I and a second image forming unit II are arranged at a fixed interval. The first image forming unit I is detachably mounted to the apparatus main body by a pair of channel-shaped guides 70 provided on the apparatus main body side and a rail 71 provided on the image forming unit side.
A charger 16 composed of a roller for uniformly charging the surface of a photosensitive drum 15 as an image carrier;
5 is mainly composed of a writing unit 17 for writing on the charged surface 5 with a beam modulated by an image signal based on a document, a black developing unit 18, and a cleaning unit 19. The first image forming unit I includes the photosensitive drum 1
5 is slidable in the axial direction, and can be removed from the apparatus main body by pulling it out toward the front side of the apparatus main body.

The second image forming unit II has the same configuration as the first image forming unit I, and
, A charger 26, a writing unit 27, and a red developing device 2
8. A cleaning means 29 is provided, and is detachably mounted on the apparatus main body in the same posture as the first image forming unit I. The rotation of each of the photosensitive drums 15 and 25 of the image forming units I and II is synchronized with the traveling of the intermediate transfer belt 10, and the peripheral speed thereof is determined to exactly match the traveling speed of the intermediate transfer belt 10. ing. Charger 16, 2
Instead of 6, charging means using a corona discharger or a brush may be employed.

Chargers 16 and 26 and writing means 17 and 2
7, each photosensitive drum 1 formed by a known method.
Each of the electrostatic latent images on the developing rollers
The developing devices 19 and 29 for developing at 0 and 31 respectively include a developer agitator, a toner replenishing device, and the like.
Other known color developing devices described in JP-A-160697 can be employed.

A first transfer roller 51 and a second transfer roller 52, to which a bias voltage for transfer is applied, are respectively attached to and separated from the photosensitive drums 15 and 25 with the intermediate transfer belt 10 therebetween. The drive roller 11 is provided with a transfer roller 53 to which a bias voltage for transfer is applied so as to be able to freely contact and separate via the intermediate transfer belt 10. Each of the photosensitive drums 15 and 25 is slightly separated from the intermediate transfer belt 10 downward, and the first transfer roller 51 and the second transfer roller 52 are separated upward from the intermediate transfer belt 10. , Each photoconductor drum 15,
In the step of transferring the toner image on the intermediate transfer belt 25 to the intermediate transfer belt 10, the intermediate transfer belt 10 is transferred to the photosensitive drum 1 by the first transfer roller 51 and / or the second transfer roller 52.
5 and / or 25. The drive roller 11 and the transfer roller 53 constitute a toner image transfer section 54. Instead of the first transfer roller 51 and the second transfer roller 52, a transfer unit using a corona discharger or a brush charger can be employed. The driven roller 12 is provided with a cleaning device 55 that removes toner remaining on the surface of the intermediate transfer belt 10 so as to be able to freely contact and separate.

Below the first and second image forming units I and II, a sheet feeder (not shown) for feeding the stacked transfer sheets one by one rightward in FIG. 1 is arranged. One transfer sheet P sent from the sheet feeding device is fed to the transfer unit 45 by a feed roller pair 56 and a registration roller pair 57. Above the transfer unit 54, a fixing device 62 including a heating roller 60 that is driven to rotate in the direction of arrow b and a pressure roller 61 that rotates while being pressed against the heating roller 60 is disposed. A roller 63 for applying an anti-offset liquid to the surface of the heating roller 60 contacts the heating roller 60 as necessary. On the downstream side of the fixing device 62, a paper discharge roller pair 65 for transmitting the transfer paper sent from the fixing device 62 onto a paper discharge tray 64 is arranged.

The operation of the above configuration will be described. To obtain a copy or print consisting of black characters and red characters, a black developer is applied to the developing device 18 of the first image forming unit I, and a red developer is applied to the developing device 28 of the second image forming unit II. Each used, the second image forming unit II
Charger 26 and writing means 27
Thus, an electrostatic latent image corresponding to a red character is formed, and this electrostatic latent image is visualized by the developing device 28 to obtain a red toner image. This red toner image is transferred to the intermediate transfer belt 10 by the second transfer roller 52.

On the other hand, also in the first image forming unit I, an electrostatic latent image corresponding to a black character is formed on the photosensitive drum 15 by the charger 16 and the writing means 17, and this electrostatic latent image is developed. The image is visualized at 18 to obtain a black toner image. The black toner image is transferred to the second transfer belt 10 on the second transfer belt 10.
Is transferred by the first transfer roller 51 to a position not overlapping with the red toner image obtained by the image forming unit II. When the red and black toner images are finally formed on the intermediate transfer belt 10 by the first transfer roller 51, the transfer paper sent from the paper feeding device is sent to the transfer unit 53 by the registration roller pair 57, Here, the red and black toner images are transferred to the transfer paper. The transferred red and black toner images are fixed on transfer paper by a fixing device 62, and sent out to a paper discharge tray 64 by paper discharge rollers 65. The intermediate transfer belt 10 after the transfer of the red and black toner images is removed by a cleaning device 55 to remove residual toner. If a black or red underline is present in the black characters of the document, the underline can be formed by a red underline. When a mark or pattern other than a character is written on a document, the mark or pattern is formed in red.

FIG. 2 shows a second embodiment in which a third image forming unit III is added to the first and second image forming units I and II.
Shown in The third image forming unit III has the same configuration as the first image forming unit I, and is detachably attached to the apparatus main body in the same posture as the first and second image forming units I and II. The intermediate transfer belt 110 is stretched between a driving roller 111 and a driven roller 112, and is driven by the driving roller 111 to travel in the direction of arrow a.

The operation of this embodiment will be described. To obtain a copy or print consisting of black characters, red characters, and blue characters, a black developer is used in the first image forming unit I, a red developer is used in the second image forming unit II, and a third image forming unit is used. A blue developer is used for Unit III. An electrostatic latent image corresponding to a blue character is formed on the photosensitive drum 35 of the third image forming unit III by the writing means 37, and this electrostatic latent image is visualized by the developing device 38 to obtain a blue toner image. Can be This blue toner image is transferred to the intermediate transfer belt 110 by the third transfer roller 66.

On the other hand, the electrostatic latent image corresponding to the red characters formed on the photosensitive drum 25 of the second image forming unit II is visualized by the developing device 28 to obtain a red toner image. This red toner image is transferred by the second transfer roller 52 to a position on the intermediate transfer belt 110 that does not overlap the blue toner image obtained by the third image forming unit III.

Further, an electrostatic latent image corresponding to a black character is also formed on the first image forming unit I, and this electrostatic latent image is visualized by the developing device 18 to obtain a black toner image. This black toner image is transferred by the first transfer roller 51 to a position on the intermediate transfer belt 110 that does not overlap the red toner image obtained by the second image forming unit II. Each image of the three colors of toner transferred to the intermediate transfer belt 110 is transferred to transfer paper by a transfer roller 53 as in the first embodiment. Is removed.

The first, second, and third image forming units I,
FIG. 3 shows a third embodiment having a fourth image forming unit IV in addition to II and III. The third image forming unit IV also has the same configuration as the first image forming unit I, and is detachably attached to the apparatus main body in the same posture. First
A black developer is contained in the developing device 18 of the image forming unit I.
The developing device 28 of the second image forming unit II has a developer (C developer) made of cyan toner, and the developing device 38 of the third image forming unit III has a developer (M developer) made of magenta toner. However, the developing device 48 of the fourth image forming unit IV contains a developer (Y developer) composed of yellow toner. The intermediate transfer belt 210 includes a driving roller 211 and a driven roller 212
And is driven by the drive roller 211 to travel in the direction of the arrow a.

The operation of this embodiment will be described. When the original to be copied or printed is a color image, the photosensitive drum 4 of each of the image forming units IV, III, II, and I
Writing means 17, 27, 3
The electrostatic latent images formed in 7 and 47 are converted into Y developer, M developer,
The toner images obtained on the photosensitive drums 48, 38, 28, and 18 are developed by using a C developer and a black developer, respectively, and transferred onto the intermediate transfer belt 210 in a superimposed manner. Intermediate transfer belt 2
The full-color image transferred to the transfer belt 10 is transferred to a transfer sheet in the same manner as in the first embodiment.
Reference numeral 10 denotes a cleaning device for removing residual toner.

To obtain a copy or print consisting of black characters and red characters, the third image is added to the yellow toner image on the intermediate transfer belt 210 transferred from the photoconductor 45 of the fourth image forming unit IV. The magenta toner image is superimposedly transferred from the photoconductor of the forming unit III to obtain a red image on the intermediate transfer belt 210, and the first image forming unit I is provided on the intermediate transfer belt 210 at a position not overlapping the red image. Transfers a black toner image.

To obtain a copy or print consisting of black characters and blue characters, the third image forming unit III
The cyan toner image from the photoconductor of the second image forming unit II is superimposed on the magenta toner image on the intermediate transfer belt 210 transferred from the photoconductor of
A black image is transferred from the first image forming unit I to a position on the intermediate transfer belt 210 that does not overlap the blue image.

Similarly, the fourth image forming unit IV, the second
Image forming unit II and first image forming unit I
By selecting, a copy or print consisting of black characters and green characters can be obtained. Even when text is underlined or marked, a desired color underline or mark can be obtained by the four image forming units.

In the first to third embodiments, each image forming unit having a photoreceptor drum and a developing unit has the same configuration, and is arranged at regular intervals along one plane of the intermediate transfer belt. Also, since the image forming units having the same configuration are arranged in the same posture, one plane of the intermediate transfer belt is not limited to the horizontal plane, and may be a vertical plane or an inclined plane. Absent. Although not shown in each embodiment, when the present invention is applied to an electrophotographic copying machine, means for reading a document to be copied is employed. As the developer used in each image forming unit, for example, gold, silver, flesh color, fluorescent color, or the like can be used in addition to red, blue, three primary colors and black toner. Since each image forming unit has the same configuration and is arranged in the same posture along one plane of the intermediate transfer belt, there is no restriction as to which color developer should be used for which image forming unit.

[0039]

According to the present invention, each image forming unit has the same structure and is arranged in the same posture along one plane of the intermediate transfer belt. There is no restriction on the use of developer, making it extremely easy to manufacture, assemble, and maintain a multi-color image forming apparatus. In addition, the use of an intermediate transfer belt solves the problem of increasing the size of the image forming apparatus. Is done.

[Brief description of the drawings]

FIG. 1 is a side view of a multicolor image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view of a multicolor image forming apparatus according to a second embodiment of the present invention.

FIG. 3 is a side view of a multicolor image forming apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

 I First image forming unit II Second image forming unit III Third image forming unit IV Fourth image forming unit IV 10, 110, 210 Intermediate transfer belt 15, 25, 35, 45 Photoconductor drum 16, 26 Charger 17, 27, 37, 47 Writing means 18, 28, 38, 48 Developing device 51 First transfer roller 52 Second transfer roller 66 Third transfer roller 67 Fourth transfer roller 53 Transfer roller 54 Transfer unit 55 cleaning device 57 registration roller 62 fixing device

Claims (14)

[Claims] An intermediate transfer belt for transferring a toner image on an image carrier; and a multicolor image forming apparatus for transferring the toner image on the intermediate transfer belt to transfer paper by a transfer unit. The image forming apparatus has at least two image forming units arranged at regular intervals along the same moving surface, and the first image forming unit is configured to store one image carrier and an electrostatic latent image on the image carrier. Developing means for developing with a developer of one color, wherein the second image forming means develops with one image carrier and a developer of a color different from the developer of the first image forming means. And a multicolor image forming apparatus. 2. The multicolor image forming apparatus according to claim 1, wherein the developing means of the first image forming means or the second image forming means is a black developing means. . 3. A multicolor image forming apparatus for transferring a toner image on an image carrier to an intermediate transfer belt and transferring the toner image on the intermediate transfer belt to transfer paper by a transfer means. It has three image forming means units arranged at regular intervals along the same moving surface, and the first image forming means forms one image carrier and an electrostatic latent image on the image carrier. Developing means for developing in black, wherein the second image forming means is one image carrier, and developing means for developing the electrostatic latent image on the image carrier with a developer of A color other than black. Wherein the third image forming means comprises: one image carrier; and developing means for developing the electrostatic latent image on the image carrier with black and a developer of B color other than A color. A multicolor image forming apparatus. 4. A multicolor image forming apparatus for transferring a toner image on an image carrier to an intermediate transfer belt and transferring the toner image on the intermediate transfer belt to transfer paper by a transfer means. It has three image forming means units arranged at regular intervals along the same moving surface, and the first image forming means forms one image carrier and an electrostatic latent image on the image carrier. Developing means for developing with a developer of color A other than black, wherein the second image forming means develops one image carrier and develops the electrostatic latent image on the image carrier with color B other than black Developing means for developing with an agent, a third image forming means having one image carrier, and a developing means for developing an electrostatic latent image on the image carrier with a developer of C color other than black. A multi-color image forming apparatus, comprising: 5. A multicolor image forming apparatus for transferring a toner image on an image carrier to an intermediate transfer belt and transferring the toner image on the intermediate transfer belt to transfer paper by a transfer means. The image forming apparatus includes four image forming units that are arranged at regular intervals along the same moving surface, and the first image forming unit is configured to use one image carrier and the electrostatic latent image on the image carrier in black. Developing means for developing the image on the image carrier, wherein the second image forming means forms one image carrier and the electrostatic latent image on the image carrier in the three primary colors A, B and C. Developing means for developing with a developer, wherein the third image forming means forms one image carrier and the electrostatic latent image on the image carrier becomes B of three primary colors of A, B and C colors. Developing means for developing with a color developer, wherein one fourth image forming means is provided. And a developing means for developing the electrostatic latent image on the image carrier with a developer of C color of the three primary colors of A, B, and C. Color image forming apparatus. 6. A multicolor image forming apparatus according to claim 1, wherein said image carrier is a drum-shaped or belt-shaped photoconductor. 7. A multicolor image forming apparatus according to claim 1, wherein each of the image forming means has the same configuration as each other,
A multicolor image forming apparatus, wherein the multicolor image forming apparatuses are arranged in the same posture in the moving direction of the intermediate transfer belt on the same moving plane, are detachable from the apparatus main body, and are mutually compatible. 8. A multicolor image forming apparatus according to claim 1, wherein each image forming means is detachable from the apparatus main body. Image forming device. 9. A multicolor image forming apparatus according to claim 1, wherein each image forming means has the same configuration as each other. Forming equipment. 10. The method of claim 1, 2, 3, 4, 5, 6, 7, or 8.
10. The multicolor image forming apparatus according to claim 9, wherein each of the image forming units is arranged in the same posture along the moving direction of the intermediate transfer belt on the same moving plane. 11. The method of claim 1, 2, 3, 4, 5, 6, 7,
11. The multicolor image forming apparatus according to 8, 9, or 10, wherein each image forming unit is unitized. 12. A multicolor image forming apparatus according to claim 2, wherein the developing means for developing in black has a larger toner capacity than the developing means for developing in other colors. Color image forming apparatus. 13. A multi-color image forming apparatus for transferring a toner image on an image carrier to an intermediate transfer belt and transferring the toner image on the intermediate transfer belt to transfer paper by a transfer means. The image forming apparatus includes at least two image forming units that are arranged at regular intervals along the same moving surface. Each image forming unit includes an image carrier and a charging unit that uniformly charges the surface of the image carrier. Means for forming an electrostatic latent image on the charged image carrier, developing means for developing the electrostatic latent image on the image carrier, and a toner image of the image carrier on the intermediate transfer belt. Each of the image forming units includes a cleaning unit that removes the toner of the image carrier after the transfer, and the image forming units have the same configuration, and have the same posture. Transfer is disposed along the moving direction of the same movement plane of the belt, and a multicolor image forming apparatus which is a detachable from the apparatus main body. 14. A multicolor image forming apparatus according to claim 13, wherein said image carrier is a drum-shaped or endless belt-shaped photoconductor, and each image forming unit is compatible with each other. Color image forming apparatus.