JP3323316B2 - Color image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image which can be applied to a color printer, a color copying machine, a color facsimile and the like.
It relates to a recording device .

[0002]

2. Description of the Related Art In general, in order to form a color image by electrophotography, a method of forming a color image by superposing toner images of yellow, magenta, cyan, and black on a transfer member has been adopted. In recent years, in order to reduce the size and simplify maintenance of such an apparatus, a plurality of image forming units are held on a rotating support as shown in JP-A-62-287264, and one exposure is performed. There has been proposed an apparatus for forming a color image on paper wound on a transfer body while exchanging an image forming unit with the means. Hereinafter, an example of such an apparatus will be described with reference to FIG.

In FIG. 3, reference numeral 101 denotes four image forming units 102a, 102a,
The rotary frame 2b, 102c, and 102d is rotatably supported by the support shaft 103 and rotates at the timing of development.

[0004] Each unit containing four color toners has the same configuration, and only the toner is different. The structure of the image forming unit and the image forming process of the image forming unit 102a stopped at the image forming position in FIG. 3 will be described in detail.

The image forming unit 102a has a photosensitive drum 108 made of a sensitized organic photoconductor, a primary charger 110, and a cleaner unit 111. On the other hand, a semiconductor laser (not shown) is provided outside the image forming unit 102a, and the signal light output from the laser is axially moved on the photosensitive drum 108 by a polygon 106 rotated at a constant speed by a motor. And exposure scanning. In FIG. 3, 1
Reference numeral 07 denotes a lens system, and reference numeral 104 denotes a mirror for changing the traveling direction of laser light.

[0006] The signal light output from the semiconductor laser according to the image signal of each color exposes the photosensitive drum 108 uniformly charged by the charger 110 to form an electrostatic latent image.
Thereafter, the electrostatic latent image is developed by the developing device 109 to form a toner image on the photosensitive drum 108. On the other hand, the transfer material is fed by a feed roller 114 and is uniformly wound around the surface of the transfer drum 112. The toner image formed on the photosensitive drum 108 is transferred onto a transfer material wound around the transfer drum 112 by a transfer charger 113 provided inside the transfer drum 112.

After the transfer, the toner remaining on the photosensitive drum 108 is collected by a cleaner unit 111. The photosensitive drum 10 whose surface has been cleaned by the cleaner unit 111
Numeral 8 stops the rotation after the charge is removed by the charge removing lamp 105.

After the above-described image forming operation is completed, the rotating frame 101 is rotated by 90 ° and each unit is rotated by 90 ° so that the unit 10 is located at the lowest image forming position.
In place of 2a, the unit 102b moves and stops and is fixed.

Next, an image is created using the unit 102b. For this, the semiconductor laser is modulated according to the image signal corresponding to the color of the toner in the unit 102b,
02b, a latent image is formed and development is performed.
2 is superimposed and transferred on the toner image already transferred on the transfer material wound around 2. The following process is unit 1
02a.

As described above, the image forming process is performed for each of the four units, and four color toner images are superimposed on the transfer material held on the transfer drum 112 to form a color image. The transfer material on which the color image is formed is separated from the transfer drum 112 by the separation claw 115. Thereafter, the transfer material is conveyed on a conveyance belt 116, where the toner image is fixed by a fixing device 117, and then discharged onto a tray 118.

[0011]

When an image is output by the above-described apparatus, the toner image on the transfer material is rubbed on the surface of the photosensitive drum when the image forming unit is moved to replace the image forming unit. A good color image could not be obtained because the image due to the toner other than the color was disturbed.

An object of the present invention has been made in view of the above problems, no disturbance of the toner image, good good mosquito maintainable small
The present invention provides a color image recording apparatus .

[0013]

In order to achieve the above object, a color image recording apparatus according to the present invention comprises a plurality of image forming units having a toner accommodating section, a photosensitive member, and a developing roller. A color image recording apparatus having an image forming position, the image developed on the photoreceptor at the image forming position being transferred to a recording sheet via an intermediate transfer member rotatably housed in an intermediate transfer unit; Rotation of the rotating body
Moving the image forming unit to the image forming position.
The start and completion of the replacement operation is determined by the development process of the specific color.
Before and after the image is formed on the intermediate transfer body.
While the unprinted part passes through the transfer position,
It is characterized by doing .

Further, the color image recording apparatus of the present invention has a rotating body in which a plurality of image forming units each having a toner accommodating section, a photoconductor and a developing roller are detachably mounted. the developed image on, housed in the intermediate transfer unit via a rotatably configured intermediate transfer member, the color image recording apparatus for transferring the recording sheet, the
Immediately after the first color transfer, a toner image of the intermediate transfer body is formed.
The rotation of the rotator is performed while the
Starts to move, and the toner image on the transfer body moves to the transfer position.
Rotating the image forming unit while passing,
The toner image is formed again after the intermediate transfer member makes one rotation.
The image forming unit for the second color is formed while the non-existent portion passes the transfer position.
Place the knit at the image forming position and rotate the rotating body.
Complete .

[0015]

[0016]

[0017]

According to the structure of the present invention, when the image forming unit is replaced.
The image on the intermediate transfer member is rubbed on the surface of the photoreceptor
There is no. Also, by utilizing the rotational movement of the image forming unit group
Prevents contact between the intermediate transfer member and the image forming unit,
Intermediate rotation with each image forming unit without adding
The contact with the object can be prevented. Also, complicated machines
Since there is no additional structure, the size of the device can be reduced.
You. Therefore, a compact and
A color image recording apparatus with excellent tenability can be realized.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to an
Developing means having a carrier and developers of different colors
Each having a different color on the electrostatic image carrier.
A plurality of image forming units capable of forming a toner image, and the image
Superimpose multiple color toner images formed by the forming unit
Transfer body that can form a color image
Transferring the toner image on the electrostatic image carrier to the transfer body
Transfer means and a single exposure associated with the transfer position
Exposure means for performing image exposure at positions, and the plurality of image forming units.
Each of the sheets corresponding to the exposure position and the transfer
To sequentially position the image forming position corresponding to the position
Moving means for rotating and moving the entire image forming unit group;
And forming a toner image of at least one color on the transfer body.
After the formation, the toner from the image forming unit to the transfer body is
-Tones that have already been transferred onto the transfer body except during the image transfer process
When the toner image forming portion passes through the transfer position,
All of the image forming units are located at the image forming position.
A color image recording apparatus. Sa
Furthermore, the present invention provides an electrostatic image carrier in which
And developing means having developers of different colors, respectively.
The toner images of different colors are formed on the electrostatic image carrier.
A plurality of image forming units that can form
Knitting multiple color toner images
A transfer member capable of forming a color image and the static transfer member at a single transfer position.
Transfer means for transferring the toner image on the electrophotographic image bearing member to the transfer member
Step and a single exposure position associated with the transfer position
Exposure means for performing image exposure; and
Each corresponds to the exposure position and the transfer position
Image formation to sequentially locate the corresponding image formation positions
Moving means for rotating and moving the entire unit group,
A first color formed on the transfer body by a first image forming unit
After transferring the toner image of the eye, the second image forming unit forms
Before transferring the formed toner image of the second color, the first color
The transfer member having the toner image of
A moving period during which the image forming unit is moved.
A color image recording apparatus characterized by performing a rotational movement of a group.
It is a place. Furthermore, the present invention provides that
An image carrier having an electrostatic image carrier and developers of different colors, respectively.
Image means, each of which is different on the electrostatic image carrier.
A plurality of image forming units capable of forming a color toner image,
The multi-color toner images formed by the image forming unit are superimposed.
A transfer body that can form a color image by bonding and a single transfer
Transfer the toner image on the electrostatic image carrier to the transfer
Transfer means for copying, and a single unit corresponding to the transfer position
Exposure means for performing image exposure at an exposure position, and the plurality of image forms
Each of the forming units corresponds to the exposure position and
To be sequentially located at the image forming position corresponding to the transfer position.
Moving means for rotating the entire image forming unit group
And the image forming unit by the moving means.
Start and completion of the replacement operation for the image forming position
Is a portion where the toner image is not formed on the transfer body.
It is performed while passing through the transfer position
It is a color electrophotographic apparatus. Furthermore, the present invention provides
The rotating electrostatic image carrier and the different colors
Developing means having a developing agent, the developing means comprising:
Multiple images that can form toner images of different colors
Forming unit and a plurality formed by the image forming unit
Transfer that can form a color image by superimposing color toner images
And a toner image on the electrostatic image carrier at a single transfer position
Transfer means for transferring the image to the transfer body;
Exposure means for performing image exposure at the assigned single exposure position
And exposing each of the plurality of image forming units to the exposure
To the image forming position corresponding to the transfer position and the transfer position.
Rotate the entire image forming unit group to position it sequentially
Moving means for moving;
During the rotation of the image forming unit group, the plurality of
Not all image forming units are located at the image forming position
The rotational movement by the moving means stops or waits in a state
Is a color image recording apparatus. Configuration of the present invention
In, directly on the transfer body, or held on the transfer body
Toner image formed on transfer material (hereinafter referred to as both
The toner image on the transfer body)
Of the image forming unit when passing through the toner image transfer position
The photoreceptor at the only position that can contact the transfer surface
Because the toner is not at the transfer position,
The image does not come into contact with any part of the imaging unit.
The toner image on the transfer body is not rubbed and disturbed.
No. Also, usually, the photoconductor and the transfer member come in contact with each other and
To avoid disturbing the toner image,
-While the image passes through the transfer position,
A mechanism that can be used to separate
Methods such as applying an electric field are applied to prevent reverse transfer
However, these methods require complicated separation mechanisms or electric fields.
Requires a charger and power supply, and the sequence becomes complicated.
You. In contrast, in the configuration of the present invention, the image forming unit
Contact between transfer body and image forming unit using rotational movement of group
Device can be miniaturized, and
There is no need to add a complicated mechanism. In addition, the image forming unit
The photoconductor and the transfer member are
Caused a temporary difference in peripheral speed, so that a toner image was formed.
Performing these operations in the area may cause the toner image to be disturbed.
However, in the present invention, both operations are performed with the toner image on the transfer body.
Since the operation is performed in the area where the toner image is not formed, the toner image may be disturbed.
And not. Furthermore, make the transfer body circumference longer than the maximum image length.
Then, create a part where the toner image is not formed on the transfer body,
In this part, the photoconductor and the transfer body are exchanged.
The toner image on the transfer body is not formed immediately after the first color transfer
Involves a rotational movement while the part
In order to perform all the image forming unit replacement operations,
The portion where the toner image is not formed needs to be considerably long.
As a result, the perimeter of the transfer member becomes longer and the device becomes larger.
You. On the other hand, in the present invention, the first color toner image is transferred.
Immediately after that, the part where no toner image is formed passes through the transfer position.
The rotation of the image forming unit is started while passing the first color.
Move the photoreceptor of the eye image forming unit away from the transfer
While the upper toner image passes the transfer position, the image forming unit
After the rotation of the cartridge, the transfer member makes one rotation and
ー A part where no image is formed passes the transfer position
During this time, the photoconductor of the image forming unit for the second color contacts the transfer body
To complete the rotational movement of the image forming unit.
It is necessary to lengthen the portion of the photo object where no toner image is formed.
It is unnecessary, the circumference of the transfer body is shortened, and the device can be downsized.
You. In addition, the rotation of the image forming unit is stopped halfway
Image forming unit according to the position of the toner image on the transfer member.
Control the timing of the rotation of the
In addition to being easy to align, the toner image on the transfer
Operation of bringing the photoreceptor into contact with the transfer member
The operation of completing the rotation of the
Wear. Hereinafter, the configuration of the color image recording apparatus will be described with reference to the drawings, taking a color electrophotographic apparatus as an example .

FIG. 1 is an overall configuration diagram of a color electrophotographic apparatus according to an embodiment of the present invention. First, almost in the center, black, yellow,
Four fan-shaped image forming units 1Bk, 1Y, 1M, and 1C for each color of magenta and cyan form an image forming unit group, and are arranged in an annular shape as shown in the figure. Each image forming unit is made of the same constituent members except for the developer contained therein, so that the image forming unit for black will be described for simplification of description, and the other colors will be omitted. Note that, for each color, the same portions are denoted by the same reference numerals, and if it is necessary to distinguish each color, a character indicating each color is denoted by the reference numeral. FIG. 2 shows a black image forming unit 1B.
The details of k will be shown.

In FIG. 2, reference numeral 9 denotes an organic photoreceptor in which phthalocyanine is dispersed in a polycarbonate binder resin;
0 is a charging roller for negatively charging the photoreceptor, 13 is signal light by a laser beam, 14a is a first hopper containing a developer obtained by mixing a carrier and toner, and 14b is a first hopper containing only toner. Two hoppers, 15 is an opening opened for toner supply, 16 is a lid for opening and closing the opening 15, 17 is an agitator for toner supply, and 18a and 18b are developers in the first hopper 14a. Is an agitator for transporting to the developing section.

Reference numeral 19 denotes a rotatable developing electrode roller made of aluminum; 20, a non-rotating magnet coaxially fixed inside; 20, an AC high-voltage power supply for applying a voltage to the developing electrode roller 19; Is a magnetic blade that regulates the thickness of the toner layer. The diameter of the photoconductor 9 is 30 m
m, the electrode roller 19 was rotated in the direction of the arrow at a peripheral speed of 60 mm / s, and the electrode roller 19 was 16 mm in diameter and rotated in the direction of the arrow at a peripheral speed of 60 mm / s.

In the first hopper 14a, a ferrite carrier 2 having a surface coated with a silicon resin and having a particle size of 50 μm is provided.
Two-component developer 26B obtained by mixing 4Bk and toner 25Bk
k was added, and was adhered to the surface of the photoreceptor 9 by magnetic force. The toner used is obtained by dispersing a pigment or the like in a polyester resin and further adding an additive.

In the second hopper 14b, 400 g of toner is hermetically stored at the time of assembling the image forming unit, and it is possible to output 5,000 originals corresponding to 5% A4 single color without replenishing toner from outside the unit. ing.

Reference numeral 27 denotes a cleaner for cleaning the toner remaining on the surface of the photosensitive member after the transfer. The operation of the image forming unit configured as described above will be described below with reference to FIG.

The photosensitive member 9 is charged with a charging roller 10 at -700 V
Was charged. The photosensitive member 9 was irradiated with signal light 13 by a laser beam to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -100V.

The surface of the photosensitive member 9 is coated with a two-component developer 26B.
K was passed in front of the rotating electrode roller 19.
At this time, when the photosensitive member 9 passes through the uncharged region, the AC voltage (frequency: 750 V0-p (peak-to-peak 1.5 kV)) obtained by superimposing a DC voltage of +100 V is applied to the electrode roller 19 by the AC high-voltage power supply 21. (1.8 kHz). Thereafter, when passing through the surface of the photoconductor 9 on which the electrostatic latent image has been written and charged to -700 V, the electrode roller 19 is superposed with a DC voltage of -400 V by the AC high voltage power supply 21 to 750 V0-p (peak-to-peak). An AC voltage (frequency: 1.8 kHz) with a peak of 1.5 kV was applied. Then
A negative-positive inverted toner image was left only on the image area on the photoreceptor 9.

Thus, a black toner image is obtained on the photoreceptor 9. The image forming unit in FIG. 2 is the image forming unit 1Bk for black, and also shows the vertical position of the image forming unit at the image forming position. In the figure, toner 2
Since the developer second hopper 14b containing 5Bk is located above the first hopper 14a and the cleaner 27 is located below, the feed mechanism for moving the developer and toner inside the toner hopper 14b and inside the cleaner is used. The toner can be smoothly replenished and cleaned without providing a stirring mechanism. That is, in the toner hopper 14b, the toner is supplied to the vicinity of the opening 15 by the rotation of the unit and by its own weight, and in the cleaner, the toner scraped by the blade falls to the bottom of the cleaner by its own weight and separates from the photosensitive member 9 .

Reference numeral 28 denotes a photoreceptor cover for protecting the photoreceptor 9, and FIG. 2 shows a state in which the photoreceptor 9 is opened for image formation. The photoconductor cover 28 covers the photoconductor 9 when the image forming unit is located at a position other than the image forming position, and is configured to prevent contamination of the photoconductor 9 and contamination inside the apparatus due to toner when the unit rotates. I have.

Image forming units 1Y, 1 other than black
M and 1C have the same configuration and operate.

Referring again to FIG. 1, the configuration of the printer unit will be described. Image forming unit 1B arranged in an annular shape
k, 1Y, 1M and 1C are supported by a support body 6 and are driven by a moving motor 30 as a moving means controlled by a control circuit 29 as a whole, around a cylindrical fixed and non-rotating shaft 31. Can be rotated in the direction of the arrow. Each image forming unit sequentially has an image forming position 5 facing a transfer roller 33 that supports an intermediate transfer belt 32 described later.
It is moved to 0 and positioned. The image forming position 50 is also an exposure position by the signal light 13, and is also a transfer position where each color toner image is transferred onto the intermediate transfer belt 32.

Reference numeral 3 denotes a laser exposure device, which is a signal light 13 of a laser beam modulated by a signal input to a printer unit.
Which is generated by the image forming units 1Bk and 1Bk in FIG.
The light enters the mirror 5 fixed inside the shaft 31 through a transparent window 4 opened in a part of the shaft 31 through the optical path formed between the fan-shaped portions of C, and is reflected to the image forming position 50. The photosensitive member 9 of a certain image forming unit 1Bk is irradiated to form a latent image. In the state of FIG. 1, it acts on the image forming unit 1Bk for black. Note that the exposure position on the photoconductor 9 was located substantially opposite to the transfer position, and the circumference of the photoconductor from the exposure position to the transfer position was 47 mm.

Reference numeral 32 denotes an intermediate transfer belt having a thickness of 100 μm.
It is made of an endless belt-shaped film made of semiconductive urethane as a base material, and is wound around a transfer roller 33 and a stainless roller 34 formed of urethane foam having a low resistance treatment formed around the film, and can be moved in the direction of the arrow. Has become. The circumference of the intermediate transfer belt 32 is 340 mm.
When an image of four sizes is output, a portion where a 46 mm toner image is not formed on the intermediate transfer belt 32 between the rear end and the front end of the image is formed.

The transfer roller 33 is lightly pressed against the photosensitive member 9 of the unit 1Bk at the image forming position via the intermediate transfer belt 32. A second transfer roller 35 having the same configuration as the above-described transfer roller 33 is lightly pressed against the roller 34 via the intermediate transfer belt 32 so as to be driven and rotatable.

Intermediate transfer belt 32 and second transfer roller 35
A paper transport path is formed in the pressed nip portion so that the paper is sent from the paper supply unit 36.

Reference numeral 8 denotes an optical position detection sensor for detecting an image position on the intermediate transfer belt 32, which is provided at a position corresponding to a position 50 mm upstream of the transfer position in the belt traveling direction of the intermediate transfer belt 32. The length from the transfer position to the position detection sensor 8 is set so that the exposure can be started after the position detection sensor 8 detects the position of the image.
The length is slightly longer than the circumference from the exposure position to the transfer position.

Reference numeral 60 denotes a toner density sensor of a magnetic resistance type installed on the shaft 31.
First hopper 1 of the image forming unit when positioned at
4a so that the toner density in the area 4a can be detected.

Reference numeral 40 denotes a belt cleaner section including a belt cleaner for cleaning the intermediate transfer belt 32 .

A fixing device 44 fixes the toner image on the sheet after the transfer, and a discharge roller 45 discharges the sheet after the fixing.

The main constitutions of the color electrophotographic apparatus and the image forming unit according to the embodiment of the present invention have been described above. Next, the operation of this apparatus when forming a color image will be described.

First, each image forming unit is located at the position shown in FIG. 1 and the image forming unit 1Bk for black is used.
Is positioned at the image forming position 50, and the toner density sensor 60 is positioned so as to substantially contact the side wall of the image forming unit. This position 50 is also a position facing the transfer roller 33. The black signal light is input to the image forming unit 1Bk by the laser exposure device 3, the operation of the image forming unit is started, and an image is formed with black toner. Simultaneously with the start of image formation, the toner density sensor 60 starts detecting the toner density of the developer in the first hopper 14a,
In response to the detection signal, when the toner in the first hopper 14a runs short, the agitator 17 pushes the lid 16 open to supply toner.

The image forming speed of the image forming unit 1Bk (equal to the peripheral speed of the photosensitive member) and the moving speed of the intermediate transfer belt 32 are set to be the same. By the operation, the black toner image is transferred to the intermediate transfer belt 32. When the transfer of the black toner image is completed, the moving motor 30 starts rotating the image forming unit group before the leading end of the black toner image on the intermediate transfer belt 32 reaches the transfer position. Then, the transfer belt 32
While the upper black toner image passes through the transfer position, the moving motor 30 rotates by 70 ° in the direction of the arrow in FIG. 1 and stops. Since the portion of the image forming unit other than the photoreceptor is located inside the rotation arc at the tip of the photoreceptor, the intermediate transfer belt
32 does not contact the image forming unit.

Thereafter, the position detection sensor 8 detects the rear end of the black toner image on the intermediate transfer belt 32 and sends a signal indicating the passage of the rear end of the image to the control circuit 29. In response to the signal, the control circuit 29 instructs the stopped moving motor 30 to start moving again. Movement motor 3 resumed movement
0 is the photosensitive member of the image forming unit 1Y just after the rear end of the black toner image on the intermediate transfer belt 32 has passed the transfer position.
The image forming unit 1Y is positioned at the image forming position 50 so that the intermediate transfer belt 9 and the intermediate transfer belt 32 come into contact at the transfer position, and the rotational movement ends. The image forming unit 1Y starts rotating the photoconductor 9 and the electrode roller 19 simultaneously with the positioning. Next, the position detection sensor 8 detects the leading edge of the black toner image on the intermediate transfer belt 32 and sends a signal indicating that the leading edge of the black toner image has passed to the control circuit 29. In response to this signal, the control circuit 29 instructs the laser exposure device 3 to start exposure at a timing such that the leading end of the yellow toner image coincides with the leading end of the black toner image on the intermediate transfer belt 32. To start. The laser exposure device 3 which has received the instruction inputs signal light to the image forming unit 1Y with a yellow signal as before, and the yellow toner image is formed and transferred. During this time, the second transfer roller 35 and the cleaner section 40 are slightly separated from the intermediate transfer belt 32 , and do not act on the toner image thereon.

The same operation as described above is performed for magenta and cyan, and four color toner images are superimposed on the intermediate transfer belt 32 in a position-matching manner to form a color image. After the transfer of the final cyan toner image, the four color toner images are collectively transferred to the sheet sent from the sheet feeding unit 36 at the same time by the action of the second transfer roller 35. The toner image transferred to the paper is fixed by the fixing device 44.
Thereafter, the sheet is discharged out of the apparatus via a discharge roller 45. The transfer residual toner remaining on the intermediate transfer belt 32 is cleaned by the action of the cleaner unit 40 to prepare for the next image formation.

Next, the operation in the monochrome mode will be described. In the monochrome mode, first, an image forming unit of a predetermined color is moved to the image forming position 50 and positioned. Next, image formation of a predetermined color and transfer to the intermediate transfer belt 32 are performed in the same manner as before, and the transfer is continued as it is after the transfer to the sheet fed from the sheet feeding unit by the next second transfer roller 35. The transcription is done.

The above is the description of the configuration and operation of the embodiment.
According to the present invention, since the image formation of each color is performed at the same image forming position without using a transfer drum having a complicated structure, accurate color registration can be performed with a simple structure, and The forming units are completed independently as one image forming unit for each color, and have excellent maintenance characteristics such as simple configuration and easy replacement of each color. Become.

In this configuration, since each of the image forming units 1Bk, 1Y, 1M, and 1C including the photosensitive member 9 can be independently adjusted externally, for example, the image shape already adjusted at the time of shipment from the factory.
The unit can be easily replaced on site without adjustment.

Since the photosensitive member 9 is covered except during image formation, the photosensitive member 9 is not damaged or stained, and the inside of the apparatus is not stained by scattering of the developer.

Further, in this configuration, since the size of the intermediate transfer member can be reduced, the size of the apparatus can be reduced, and the registration position of each color toner image on the intermediate transfer member can be easily and accurately adjusted.

In the above embodiment, a color image is formed by superimposing toner images of each color on the intermediate transfer belt 32 as an intermediate transfer member. However, a drum is used as an intermediate transfer member to form a toner image of each color thereon. In a configuration in which a color image is formed by superimposing, a transfer material such as paper is held on an intermediate transfer body such as a drum and a belt, and toner images of each color are sequentially transferred directly onto the transfer material and superimposed. The essence of the present invention and the function and effect are not changed even when the color image is formed.

In the above embodiment, the separation / contact operation of the photosensitive member and the intermediate transfer member is performed by using the rotational movement of the image forming unit. However, in order to easily and surely perform this operation,
The essence and function and effect of the present invention do not change even if the mechanism is used to change the contact pressure between the photoreceptor and the intermediate transfer member and the amount of bite without using the simple mechanism.

In the above embodiment, a two-component developing method in which a carrier and a toner are mixed is used as a developing method used for an image forming unit. And the effect does not change.

[0052]

As described above, in the present invention, since the image formation of each color is all performed at the same image formation position, accurate color registration can be performed with a simple configuration. While the toner image already transferred on the intermediate transfer member passes through the transfer position, the image forming unit rotates and does not come into contact with the intermediate transfer member so that the toner image on the intermediate transfer member is not disturbed. Can be shortened. Since the timing is controlled by stopping the rotational movement of the image forming unit in the middle, the separation and contact of the photoconductor and the intermediate transfer body at a portion where the toner image is not formed on the intermediate transfer body can be easily performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a color electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an image forming unit used in the color electrophotographic apparatus according to the embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional color electrophotographic apparatus.

[Explanation of symbols]

 1Bk, 1C, 1M, 1Y Image forming unit 3 Laser exposure device 5 Mirror 6 Support 8 Position detection sensor 9 Photoconductor 13 Signal light 28 Photoconductor cover 32 Intermediate transfer belt 33 Transfer roller 35 Second transfer roller 50 Image formation position 60 Toner density sensor

Continuation of the front page (56) References JP-A-5-216325 (JP, A) JP-A-5-323761 (JP, A) JP-A-62-287264 (JP, A) JP-A-60-33575 (JP) JP-A-63-23173 (JP, A) JP-A-2-135379 (JP, A) JP-A-3-87861 (JP, A) JP-A-63-23171 (JP, A) 63-191169 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/01-15/01 117 G03G 15/16 G03G 15/08-15/095

Claims (2)

(57) [Claims] An image forming unit including a plurality of image forming units having a toner storage unit, a photoconductor, and a developing roller, the image forming unit being detachably attached to the image forming unit. In a color image recording apparatus for transferring to a recording sheet via a rotatable intermediate transfer member accommodated in a transfer unit, a start of a switching operation of the image forming unit with respect to the image forming position due to a rotational movement of the rotator And completion,
While the front and rear both at a by no image is formed on the intermediate transfer body portion of a particular color transfer process is passing through the transfer position, the color image recording apparatus characterized by performing, respectively. An image forming unit including a plurality of image forming units including a toner storage unit, a photoconductor, and a developing roller, the image forming unit being detachably attached to the image forming unit. In a color image recording apparatus that transfers to a recording sheet via a rotatable intermediate transfer member accommodated in a transfer unit, a toner image of the intermediate transfer member is formed immediately after the first color transfer.
While the unexposed part passes through the transfer position,
Rotational movement is started, and the toner image on the transfer body is moved to the transfer position.
The image forming unit is rotated while passing through
The intermediate transfer member makes a full circle to form a toner image again.
The image of the second color while the unexposed part passes through the transfer position
The rotating unit is arranged at the image forming position,
A color image recording apparatus , wherein the operation is completed .