JP3231037B2 - Color image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color printer,
The present invention relates to a color image recording apparatus applicable to a color copying machine, a color facsimile, and the like.

[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 material has been adopted. As a method of forming this color image, a toner image of each color is sequentially formed on one photoconductor, and the transfer material wound around the transfer drum is rotated to repeatedly oppose the photoconductor, and the color of each color sequentially formed there is formed. A transfer drum system in which toner images are superimposed and transferred, and a plurality of image forming units are arranged side by side, and each color toner image is sequentially transferred to a transfer material conveyed by a belt or the like by passing through the position of each image forming unit. In general, a continuous overlapping method in which the sheets are overlapped is performed.

The former using the transfer drum system is an example of a color image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 1-252982.

FIG. 4 shows an outline of the entire configuration of the conventional example, and the configuration and operation will be briefly described below. In FIG. 4, reference numeral 101 denotes a photosensitive member, and
02, a developing unit 103, a transfer drum 104, and a cleaner 105 are provided. The developing unit 103 includes a Y developing unit 106 for forming a yellow toner image, an M developing unit 107 for magenta, and a C developing unit 10 for cyan.
8, a K developing device 109 for black, and the whole is rotated so that each developing device can be developed in a state where the developing device can face the photoconductor 101 sequentially.

During operation, the transfer drum 104 and the photoreceptor rotate at a constant speed in the direction of the arrow while facing each other.

First, when the operation is started, the photosensitive member 101 rotates in the direction of the arrow, and the surface thereof is uniformly charged by the charger 102.

Thereafter, the surface of the photoreceptor is irradiated with a laser beam 110 modulated by a signal for forming a first color yellow image.
To form a latent image. Further, this latent image is first developed in the yellow Y developing device 106 facing the photoreceptor to form a yellow toner image. By the time the formed yellow toner image comes to a position facing the transfer drum 104, one sheet of the transfer material sent from the sheet feeding unit 111 has already been formed on the outer periphery of the transfer drum 104 with the claw part. The toner image is formed such that the yellow toner image on the photoreceptor is opposed to a predetermined position of the paper and is wrapped around the paper.

After the yellow toner image on the photoreceptor is transferred to the sheet by the operation of the transfer charger 113, the surface of the photoreceptor is cleaned by the cleaner 105 to prepare for the formation of the next color image. Subsequently, magenta, cyan, and black toner images are formed in the same manner. At that time, the developing unit 103 sets each developing unit that uses the color corresponding to the photoconductor to be in a developable state. The diameter of the transfer drum is large enough to allow the longest sheet to be wound and to replace the developing device between the images of each color.

Laser beam 110 for forming images of each color
Is performed at a timing such that the toner images of the respective colors on the photoreceptor and the toner images already transferred onto the paper on the transfer drum are aligned and faced with each other as they rotate. In this manner, the four color toner images are transferred to the transfer drum 10.
4, the image is transferred onto the sheet, and a color image is formed on the sheet. After the toner images of all colors have been transferred, the sheet is peeled off from the transfer drum 104 by the peeling claws 114, the upper toner image is fixed by the fixing device 116 via the transport section 115, and the sheet is discharged out of the apparatus. The above is a brief description of the configuration and operation of the conventional example.

On the other hand, as an example of a color image forming apparatus using the continuous transfer system, there is Japanese Patent Application Laid-Open No. 1-250970. In this example, four image forming stations each including a photoreceptor and an optical scanning unit are arranged for forming images of four colors, and the paper conveyed to the belt passes under the respective photoreceptors and passes therethrough. The toner images are superimposed.

Further, as another method of forming a color image by superimposing toner images of different colors on a transfer material, a method of superimposing toner images of respective colors sequentially formed on a photoreceptor on an intermediate transfer member is performed. Is transferred to the transfer material at once as disclosed in JP-A-2-183276.

[0012]

Among the conventional examples described above, in the transfer drum system, a transfer drum is used to align and overlap toner images of different colors. The transfer drum is rotated at the same speed with respect to the photosensitive member, and the timing of the leading edge of the image is adjusted to match the mutual positions of the toner images of the respective colors when a color image is formed. However, in the above configuration, since the paper must be wound around the transfer drum, the diameter of the transfer drum needs to be a certain size or more, and the structure is very complicated. Had become.

Further, rigid paper such as postcards and cardboard cannot be used because they cannot be wound around the transfer drum.

Further, maintenance such as replacement of the photoreceptor requires a very complicated operation, and requires a skilled expert.

On the other hand, the continuous transfer system has an image forming position corresponding to the number of colors, and a sheet is required to be passed one after another. Therefore, a transfer drum is not necessary. A latent image forming means such as a laser optical system for forming a latent image is required corresponding to the number of colors, and the structure is very complicated and expensive at this portion. Furthermore, since there are a plurality of image forming positions, the relative positional relationship between the image forming units of each color greatly affects the color shift. In particular, it is necessary to accurately position each color of the latent image by the latent image forming means, and as shown in the example of JP-A-1-250970, the image exposure system of the latent image forming means is required. There was a problem that a considerable device and a complicated configuration were required.

In addition, when components such as a photoconductor are replaced during maintenance due to the complexity of the alignment, accurate reproducibility of the alignment is extremely difficult, and the maintenance is complicated.

Further, JP-A-2-1 using an intermediate transfer member
In the example disclosed in JP-A-83276, the shape of the photoconductor becomes large so that a toner image of each color can be formed on one photoconductor by each color developing unit. For example, a belt-shaped photoconductor is required. It becomes. In addition, there is a problem that the maintenance of the developing units and the photosensitive members of each color is also difficult. For example, each developing device requires image adjustment and position adjustment with the photoconductor at the time of maintenance, and the same applies when the photoconductor is replaced.

In view of the above problems, it is an object of the present invention to eliminate the need for a complicated transfer drum and a complicated structure for aligning an image exposure system. An object of the present invention is to provide an excellent color image recording apparatus which can be accurately performed, has a simple configuration of a toner image forming section including a photoconductor and a developing device, is small in size, and has good maintainability.

[0019]

In order to achieve the above object, a color image recording apparatus according to the present invention rotates a plurality of individual units each having an opening for supplying the color toner contained therein to the outside of the unit. In a state where the opening is detached in the direction perpendicular to the axis and arranged and arranged in a substantially columnar shape, and stops at a state where the opening is located at an exchange position, and the opening is directed upward. Said individual
The unit is moved vertically from the opening / closing part on the top of the device to the axis of the rotating body.
The individual unit can be taken out in the vertical direction and
The opening is inserted from the opening / closing part in a direction perpendicular to the axis of the rolling body.
A rotating body that can be mounted with its face up
Moving means for rotating the rotating body;
The image formed on the photoreceptor by the toner
Transfer and further transfer the image transferred to the intermediate transfer member for recording
Image forming means for fixing after transferring to paper
A color image recording apparatus, wherein each color machine during color image formation is
Within a period of time, the rotation of the intermediate transfer member is stopped or
While switching to the low-speed running state,
The rotating unit is rotated to switch the individual units.
U, adopt a configuration.

Further, in the color image recording apparatus of the present invention, a plurality of individual units each having an opening for supplying the color toner contained therein to the outside of the unit can be substantially detachably mounted in a direction perpendicular to the rotation axis. In a replacement position, the opening is stopped in a state where the opening is located upward, and the opening is directed upward.
The individual unit in the state is moved from the opening / closing section on the upper surface of the apparatus to the
It can be taken out in the direction perpendicular to the axis of the rotating body, and
A slot from the opening / closing section in a direction perpendicular to the axis of the rotating body.
And the opening can be mounted with the opening facing upward.
The, a moving means for rotating a rotating body, the rotating body,
The image formed on the photoreceptor by the color toner,
Transferred to the intermediate transfer member, and further transferred to the intermediate transfer member
Image forming means for fixing an image after transferring it to recording paper
And a color image recording apparatus comprising:
Between each color process during formation, the color image currently being transferred is processed.
After the image is transferred to the intermediate transfer body,
Rotation speed is changed from transfer speed to stop or low speed
While the intermediate transfer member is stopped or low.
When the vehicle is in a high-speed running state,
Rotate to place the individual unit for the next color in the operating position
Take a configuration.

[0021]

[0022]

According to this configuration, during the switching time of the individual units, since the rotation of the intermediate transfer body in a stopped state or a low speed running condition, the time for switching the individual unit as it is but, the individual units operating position of the next color The next color individual unit moves to the operating position so that the leading edge of the previous color image on the transfer body does not reach the transfer position before the leading edge of the image supplied from that individual unit reaches the transfer position. During this time, the rotation of the intermediate transfer member is stopped or in a low-speed running state, so that the time until the next color image is transferred onto the intermediate transfer member can be shortened. This allows the next color to be reached immediately after reaching the operating position of the individual unit for the next color.
Can be started, and the printing time can be shortened as a whole .

The peripheral length of the intermediate transfer member can be shortened by adjusting the speed of the intermediate transfer member not only when the rotation of the intermediate transfer member is stopped but also at a low speed.
That is, it is possible to reduce the length of a portion (a portion that can be called a seam) of the intermediate transfer member other than the image transfer portion. As a result, the size of the intermediate transfer unit can be reduced, and the size of the apparatus can be reduced. Furthermore, the low-speed running state is suitable especially for an apparatus in which the speed of image formation on the photosensitive member is high or when the load for driving the intermediate transfer body is large. Can be shortened until the vehicle starts running at a constant speed. As described above, according to the configuration of the present invention, it is possible to simultaneously reduce the printing time and the size of the transfer unit.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises an electrostatic image carrier, each rotating at least, and developing means having toners of different colors, respectively. A plurality of image forming units capable of forming a toner image, a transfer body capable of forming a color image by superimposing a plurality of color toner images formed by the image forming unit, and a state in which the transfer body is stopped or running at a low speed. Driving means capable of switching driving to high-speed running, transfer means for transferring the toner image on the electrostatic image carrier to the transfer body at a single transfer position, and a single exposure corresponding to the transfer position An exposure unit for performing image exposure at a position, and moving the entire image forming unit group to sequentially position each of the plurality of image forming units at an image forming position corresponding to the exposure position and the transfer position. Moving means for causing the transfer body to stop or travel at a lower speed than at the time of image formation, including part or all of the time during which the entire image forming unit group moves by the moving means. This is a color image recording apparatus characterized by the following. Further, the present invention includes an electrostatic image carrier each rotating at least, and developing means having toners of different colors, and can form toner images of different colors on the electrostatic image carrier, respectively. A plurality of image forming units, a transfer body capable of forming a color image by superimposing a plurality of color toner images formed by the image forming units, a unit for detecting a predetermined position on the transfer body, Transfer means for transferring the toner image on the electrostatic image carrier to the transfer body at a transfer position, exposure means for performing image exposure at a single exposure position associated with the transfer position, and the plurality of images Moving means for moving the entire image forming unit group to sequentially position each of the forming units at an image forming position corresponding to the exposure position and the transfer position, and detecting the position of the transfer body means When detecting the position of the transfer body, the circumferential length of the transfer body from the transfer position on the transfer body to the leading end position of the image, the electrostatic length from the exposure position on the electrostatic image carrier to the transfer position A color image recording apparatus characterized by being longer than the circumference of the image carrier. Further, the present invention includes an electrostatic image carrier each rotating at least, and developing means having toners of different colors, and can form toner images of different colors on the electrostatic image carrier, respectively. A plurality of image forming units;
A transfer body capable of forming a color image by superimposing a plurality of color toner images formed by the image forming unit, a unit for detecting a predetermined position on the transfer body, and stopping the transfer body or running at a low speed. A drive unit that can be driven to switch to constant speed traveling, a transfer unit that transfers the toner image on the electrostatic image carrier to the transfer body at a single transfer position, and a single unit that is associated with the transfer position. An exposure unit for performing image exposure at an exposure position, and moving the entire image forming unit group to sequentially position each of the plurality of image forming units at an image forming position corresponding to the exposure position and the transfer position. Moving means for changing the speed of the transfer body by the drive means, and then detecting the position of the transfer body in a state where the transfer body reaches a predetermined speed. It is a color image recording apparatus characterized by the provision. By the way, when a transfer body is run at a constant speed without using the above configuration in a color image recording apparatus that superimposes a color image on a transfer body using an intermediate transfer body, the circumference of the transfer body is determined by an image forming unit. It is necessary to increase the length of the transfer member while taking into consideration the travel length of the transfer member.
If this length is not long enough, before the movement of the unit is completed, the leading edge position of the image on the transfer body passes through the predetermined exposure start position, and again until the leading edge position of the image passes the predetermined position. Image formation cannot be started. Further, the time required for the movement of the unit tends to vary depending on the weight of the unit, the environment, and the like, and it is difficult to determine the circumference of the transfer body. In particular, in the case of an apparatus having a high image forming speed, or an apparatus in which the load of the unit movement is large and the movement takes a long time, the transfer body needs a sufficient length, and the apparatus becomes huge, and the transfer body becomes large. Operability also worsens. By using the configuration of the present invention, even in the case of a high-speed image forming apparatus,
Even in the case of an apparatus that takes a long time to move the unit, or in a case where the time required for the movement of the unit varies, the peripheral length of the transfer body does not need to be increased, and the apparatus can be downsized. Further, by making the circumference from the transfer position on the transfer body to the leading end position of the image when detecting the position of the transfer body longer than the circumference from the exposure position on the electrostatic image carrier to the transfer position, After detecting the position, the exposure can be started in accordance with the position, and accurate positioning can be performed without wasting time. Furthermore, by detecting the position of the transfer body after the speed of the transfer body reaches a predetermined speed after switching the speed of the transfer body, the travel length of the transfer body from the position detection time to the transfer time is reduced. Stable positioning can be easily realized. Hereinafter, the configuration of the color image recording apparatus will be described with reference to the drawings using 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.
k is shown in detail.

In FIG. 2, reference numeral 9 denotes an organic photoreceptor in which phthalocyanine is dispersed in a polycarbonate binder resin;
0 is a non-rotating magnet fixed coaxially with the photosensitive member 9;
Denotes a charging roller for negatively charging the photoreceptor, 13 denotes signal light by a laser beam, and 14 denotes a developer hopper.

In the developer hopper 14, a two-component developer 26 is prepared by mixing a ferrite carrier 24Bk having a particle diameter of 50 μm, the surface of which is coated with a silicone resin, and a toner 25Bk.
Bk was added, and was adhered to the surface of the photoconductor 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.

Reference numeral 17 denotes a rotatable collecting electrode roller made of aluminum, 16 denotes a non-rotating magnet coaxially fixed inside, 18 denotes an AC high-voltage power supply for applying a voltage to the collecting electrode roller, and 19 denotes a power supply on the collecting electrode roller. A scraper made of polyester film that scrapes toner. Photoconductor 9
Has a diameter of 30 mm and is rotated in the direction of the arrow at a peripheral speed of 60 mm / s. The collection electrode roller 17 has a diameter of 16 mm and a peripheral speed of 60 mm / s.
It was rotated in the direction of the arrow at mm / s.

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 photoconductor 9 was charged to −500 V by the charging roller 11. A signal light 1 by a laser beam is applied to the photosensitive member 9.
Irradiation No. 3 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor was -100V.

On the surface of the photosensitive member 9, a two-component developer 26
Bk was deposited by magnetic force in the developer hopper 14. Next, the surface of the photoconductor 9 was passed in front of the collection electrode roller 17. When the photosensitive member 9 passes through the uncharged area, the collection electrode roller 17 is superposed by a high-voltage power supply 18 on which a DC voltage of +100 V is superimposed to 750 V0-p (peak-to-peak 1.
5 kV) AC voltage (frequency 1 kHz) was applied. Thereafter, when passing through the surface of the photoconductor 9 on which the electrostatic latent image is written by being charged to −500 V, a DC voltage of −350 V is superimposed on the collection electrode roller 17 by an AC high voltage power supply 7.
An AC voltage (frequency 1.5 kHz) of 50 V0-p (1.5 kV peak-to-peak) was applied. Then, the toner adhered to the carrier and the charged portion on the photoconductor 9 was collected by the collection electrode roller 17, and a negative-positive toner image was left only on the image portion on the photoconductor 9. The carrier and the toner attached to the collecting electrode roller 17 rotating in the direction of the arrow are
It is scraped off by the scraper 19 and again the developer hopper 1
4 and used for the next image formation.

Thus, a black toner image is obtained on the photoreceptor 9. The image forming unit shown in FIG. 2 is an image forming unit for black, and also shows the vertical position of the image forming unit at the image forming position. In the figure, two-component developer 2
Since the developer hopper 14 containing 6Bk is located on the upper side and the cleaner 27 is located on the lower side, there is no need to provide a feed mechanism or a stirring mechanism for moving the developer or toner inside the developer hopper or the cleaner. However, development and cleaning can be performed smoothly. That is, in the developer hopper, the developer is supplied onto the photoconductor 9 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 photoconductor.

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

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 (not shown), and are generally driven by a moving motor 30 as moving means controlled by a control circuit 29, and are fixed in a cylindrical shape and do not rotate. It is rotatable about the axis 31 in the direction of the arrow. Each image forming unit is sequentially moved to an image forming position 50 facing a first transfer roller 33 that supports an intermediate transfer belt 32 described below, and is positioned. The image forming position 50 is also an exposure position by the signal light 13. The circumference of the photoconductor from the exposure position on the photoconductor 9 at the image forming position 50 to the transfer position is 45 mm. Image forming unit 1Bk, 1
The Y, 1M, and 1C supports have means (not shown) for detecting that each image forming unit has moved to the image forming position 50. Each time the movement of each unit is completed, it corresponds to the completion of the movement. The signal is transmitted to the control circuit 29. In this embodiment, the detecting means detects that the movement is completed.
It goes without saying that the position of the unit may be detected during the movement as long as the means for accurately predicting the time required for the completion of the movement.

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 passes through the optical path formed between the fan sectors of Y, enters the mirror 5 fixed inside the shaft 31 through the transparent window 4 opened in a part of the shaft 31, and is reflected to the image forming position 50. The photosensitive member 9 of a certain image forming unit is irradiated to form a latent image.
In the state of FIG. 1, it acts on the image forming unit 1Bk for black.

Here, since the optical path to the mirror 5 is along the wall surface of the fan-shaped image forming units on both sides, there is almost no wasteful area occupied by the image forming unit group. Further, since the mirror 5 is provided at the center of the image forming unit group, it can be constituted by only one fixed mirror, and has a simple and highly reliable structure for alignment and the like. The reflecting surface of the mirror 5 is
Since the optical path is set so as to face downward, dust and the like inside the device are less likely to collect on the reflection surface.

Reference numeral 32 denotes an intermediate transfer belt having a thickness of 100 μm.
Is wound around a first transfer roller 33 and a stainless steel roller 34, which are formed of an endless belt-shaped film made of semiconductive urethane as a base material, and around which are formed a urethane foam with a low resistance treatment, and move in the direction of the arrow. It is possible. The width of the intermediate transfer belt 32 is wider than the maximum image width (A4 in this embodiment).
A mark (not shown) for detecting a position corresponding to the traveling direction of the belt is provided outside the image area on the second belt 2, and a support (not shown) of the intermediate transfer belt 32 is provided at a position where the mark can be detected. An optical position detection sensor 60 is provided. When the position detection sensor 60 detects the position of the mark on the intermediate transfer belt 32, the image forming position 50 is
The image formation of the image forming unit starts. In this embodiment,
The position of the mark for position detection with respect to the belt traveling direction on the intermediate transfer belt 32 is made to coincide with the leading end position of the image. Was set to be at a position of 50 mm. The position detection sensor 60 includes a light emitting unit and a light receiving unit, and detects a position by receiving reflected light of light output from the light emitting unit. In this embodiment, an optical position detecting means for reading the reflected light is used as the belt position detecting means. However, the same optical type or transmission type position detecting means may be used. It goes without saying that a position detecting means or an electric position detecting means may be used.

In this embodiment, a pulse motor (not shown) is used as a driving means of the intermediate transfer belt 32. At this time, the intermediate transfer belt 32 is stopped at 60 mm / s.
It takes 0.1 s during acceleration and 0.05 s during deceleration to switch to the constant speed traveling. When the driving load of the belt is large, the time required for the speed switching is long and the variation is large. On the other hand, the intermediate transfer belt 32
The time required to switch between low-speed traveling at a speed of mm / s and constant-speed traveling at a speed of 60 mm / s is about half that in the stopped state both during acceleration and deceleration. Rarely occurs. Therefore, when the driving load is large, rather than switching between the stopped state and the constant speed traveling,
It is more effective to use switching between low-speed running in which the speed is sufficiently reduced to about 10 mm / s or less and constant-speed running at 60 mm / s, because the time required for the switching is short and the fluctuation is small.

In this embodiment, the driving load of the intermediate transfer belt 32 is sufficiently small, the variation in the acceleration / deceleration time from the stop state is small, and the positioning can be stably realized by switching between the stop state and the constant speed traveling. .

In this embodiment, the intermediate transfer belt 32
Is set to be 80 mm longer than the maximum printing length (in this embodiment, the length in the longitudinal direction of A4 paper). This is because when the position of the intermediate transfer belt 32 is detected by the position detection sensor 60 to be 20 mm until the speed of the intermediate transfer belt 32 is sufficiently stabilized when the speed is switched between the stop state and the constant speed traveling of 60 mm / s. Is a setting obtained by adding a margin of 10 mm to the length of 50 mm from the transfer position to the leading end of the image. By setting the circumference of the intermediate transfer belt 32 in this manner, the intermediate transfer belt 3 at the position where the position detection sensor 60 is installed is set.
The speed 2 always runs at a constant speed of 60 mm / s.

The first transfer roller 33 is used for the intermediate transfer belt 3
2 is lightly pressed against the photosensitive member 9 of the image forming unit 1Bk at the image forming position. A second transfer roller 35 having the same configuration as the first transfer roller 33 is lightly pressed against the roller 34 via the intermediate transfer belt 32 so as to be driven and rotatable.

The intermediate transfer belt 32 and the second transfer roller 35
The paper feed sections 36a and 36b
The paper transport path is formed so that paper is sent from the printer.

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

Reference numeral 44 denotes a fixing unit for fixing the toner image on the sheet after transfer, and reference numeral 45 denotes a discharge roller for discharging the sheet after fixing.

The main configuration of the color electrophotographic apparatus and the image forming unit according to the embodiment of the present invention has 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 a position as shown in FIG. 1 and the image forming unit 1Bk for black is used.
Are positioned at the image forming position 50. It also faces the first 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. At this time, the image forming speed of the image forming unit 1Bk (equal to the peripheral speed of the photoconductor) and the intermediate transfer belt 3
2 are set to be the same, and the image is formed and at the same time, by the action of the first transfer roller 33,
The black toner image is transferred to the intermediate transfer belt 32. Immediately after all the black toner images have been transferred, the intermediate transfer belt 32 stops, and the image forming unit groups 1Bk, 1Y, 1B
M and 1C are entirely driven by the moving motor 30 to rotate integrally in the direction of the arrow in FIG. 1, rotate exactly 90 degrees, stop at the position where the image forming unit 1Y reaches the image forming position 50, and perform image forming. The unit 1Y is positioned. During this movement, the intermediate transfer belt 32 is stopped. Since the portion of the developer hopper 14 (see FIG. 2) other than the photoconductor of the image forming unit is located inside the rotation arc at the tip of the photoconductor, the intermediate transfer belt 32 does not contact the image forming unit.

When the image forming unit 1C arrives at the image forming position 50, a signal is transmitted from the position detecting means provided on the unit support, and the stopped intermediate transfer belt 32 corresponding to the signal starts to be driven again. .

The position detection sensor 60 detects the position of the intermediate transfer belt 32 that has started running again, and issues a signal for starting image formation. In response to this signal, the laser exposure device 3 inputs signal light to the image forming unit 1Y using the yellow signal, as before, and the yellow toner image is formed and transferred. At this time, the timing of writing the yellow signal light is controlled such that the next yellow toner image is positionally matched with the black toner image previously transferred onto the intermediate transfer belt 32.
During this time, the second transfer roller 35 and the belt 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 above is performed for magenta and cyan, and four color toner images are superimposed on the intermediate transfer belt so as to be aligned with each other to form a color image. After the transfer of the last cyan toner image, the toner images of the four colors are collectively transferred to the sheet sent from the sheet feeding section 36a or 36b by the action of the second transfer roller 35 at the same time. 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 operation of the belt 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.

Next, maintenance of the apparatus will be described with reference to FIG. It is assumed that the developer of a specific color is not consumed and maintenance is performed. First, the image forming unit group is rotated by the action of the moving motor 30 controlled by the control circuit 29 in response to a command from an operator (by a switch (not shown)), and the image forming unit of the target color is moved to the upper position (FIG. 1). Image forming unit 1C
Position). Then, as shown in FIG. 3, the operator opens the cover 46 located at the upper part of the apparatus main body, and takes out only the image forming unit of interest from the outside of the apparatus. Next, a new image forming unit of the color adjusted in advance as an image forming unit is mounted.

Therefore, after mounting, image formation can be started without any adjustment. At this time, since the photoconductor cover is in the closed state, the worker does not touch the photoconductor.

Further, since the image forming unit to be replaced can be replaced at an upper position different from the image forming position, it is not hindered by the related members such as the transfer unit and is not positioned, so that it can be easily mounted outside the apparatus. It can be taken out easily and maintenance is excellent.

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 unit is completed independently as one image forming unit for each color, so that the configuration is simple, and the maintainability such as easy replacement of each color is also excellent.

Further, in this configuration, since each image forming unit including the photosensitive member can be independently adjusted externally, for example, a unit which has been adjusted at the time of shipment from a factory can be easily replaced without adjustment on site. .

Since the photoreceptor is covered except during the image formation, the photoreceptor 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.

Furthermore, in the present configuration, even when a color image is continuously formed, each photosensitive member is inactive every time while forming another color, so that a stable image without electrostatic fatigue can be obtained. can get.

In the above embodiment, a specific developing method is used for the image forming unit. However, even in the case of an image forming unit having a structure using another developing method, the essence and the function and effect of the present invention are not changed. Will not change.

[0061]

As described above, according to the present invention, the next color
Immediately after reaching the operating position of another unit, start the process for the next color
To reduce printing time as a whole.
There is an effect that can be achieved. It also collects color toner.
Using a rotating body in which individual units
In this configuration, individual units can be attached to and detached from the
When the opening / closing part is opened, the opening of the individual unit
The parts can be confirmed, and the unit can be easily replaced .

Further, since the size of the intermediate transfer member can be reduced, the apparatus can be downsized and the printing time can be shortened.
The superposition of the toner images of the respective colors on the intermediate transfer member can be easily and accurately adjusted.

[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 a color electrophotographic apparatus according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram when an image forming unit is replaced.

FIG. 4 is a configuration diagram of a conventional color image forming apparatus.

[Explanation of symbols]

 1Bk, 1C, 1M, 1Y Image forming unit 3 Laser exposure device 5 Mirror 9 Photoconductor 13 Signal light 28 Photoconductor cover 32 Intermediate transfer belt 33 First transfer roller 35 Second transfer roller 50 Image forming position

Continuation of the front page (56) References JP-A-3-191368 (JP, A) JP-A-63-177165 (JP, A) JP-A-3-1711072 (JP, A) JP-A-62-287264 (JP, A) JP-A-63-296078 (JP, A) JP-A-62-163072 (JP, A) JP-A-60-208779 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB G03G 13/01 G03G 15/01-15/01 117 G03G 15/16 G03G 15/08-15/095 G03G 15/00 550 G03G 21/16-21/18

Claims (2)

(57) [Claims] A plurality of individual units each having an opening for supplying a color toner housed therein to the outside of the unit are collectively arranged in a substantially cylindrical shape so as to be detachable in a direction perpendicular to a rotation axis; And, while stopping in a state where the opening is located at the exchange position, the individual unit in a state where the opening is directed upward,
Take out from the opening / closing part on the top of the device in the direction perpendicular to the axis of the rotating body
Possible and the individual unit is perpendicular to the axis of the rotating body.
Insert from the opening / closing part in the vertical direction and turn the opening upward
A rotating body configured to be mounted in a state where the rotating body is rotated, a moving unit for rotating the rotating body, and an image formed on a photoconductor by the color toner,
An image forming means for transferring the image transferred to the intermediate transfer member, and further transferring the image transferred to the intermediate transfer member to recording paper and then fixing the transferred image onto recording paper. A color image recording apparatus, wherein the rotation of the intermediate transfer body is switched to a stopped state or a low-speed running state, and the moving unit rotates the rotator to switch the individual units. A plurality of individual units each having an opening for supplying the color toner accommodated therein to the outside of the unit are arranged and arranged in a substantially cylindrical shape so as to be detachable in a direction perpendicular to a rotation axis; And, while stopping in a state where the opening is located at the exchange position, the individual unit in a state where the opening is directed upward,
Take out from the opening / closing part on the top of the device in the direction perpendicular to the axis of the rotating body
Possible and the individual unit is perpendicular to the axis of the rotating body.
Insert from the opening / closing part in the vertical direction and turn the opening upward
A rotating body configured to be mounted in a state where the rotating body is rotated, a moving unit for rotating the rotating body, and an image formed on a photoconductor by the color toner,
An image forming means for transferring the image transferred to the intermediate transfer member, and further transferring the image transferred to the intermediate transfer member to recording paper and then fixing the transferred image onto recording paper. In, while the image of the color currently being transferred is transferred to the intermediate transfer body, the rotational speed of the intermediate transfer body is switched from the transfer speed traveling to a stopped state or a low-speed traveling state, while the intermediate transfer body is stopped or In the low-speed running state, the rotating unit is rotated by the moving unit, and the individual unit of the next color is moved to the operating position.
Allowed to place the location, color image recording apparatus characterized by.