JP3103558B1 - Color image recording device - Google Patents

Abstract

An object of the present invention is to provide an excellent color image recording apparatus in which the configuration of an intermediate transfer unit is small, simple, and easy to maintain. SOLUTION: Developing units 1Bk, 1Y, 1M, 1C
Are mounted on the support from the cover 46 on the upper surface of the apparatus with the openings thereof facing upward, are rotated and arranged at the image forming position, and are arranged to face the photoconductor 9. The image developed on the photoconductor 9 at the image forming position is transferred to the intermediate transfer belt 32.
Is transferred to the recording paper by the second transfer roller 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color printer,
The present invention relates to a color image recording device that can be applied 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 in 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 and repeatedly opposed to 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 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. 5 shows an outline of the entire configuration of the conventional example, and the configuration and operation will be briefly described below. In FIG. 5, 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 Bk developing unit 109 for black, and the whole is rotated so that each developing unit can be sequentially developed so as to face the photoconductor 101. The toner density is detected by an optical detection means for detecting the toner density on the developing roller at the developing position, and the toner is replenished at another position rotated by 90 ° from the developing position in accordance with the toner density detected value.
When the single color is continuous, the entire unit rotates at the time when the toner density is lowered, and the developing device whose toner density is lowered is moved to the toner supply position to supply the toner. The main body is provided with a toner hopper 118 corresponding to the toner of each developing device, and a mechanism for sending the toner to a toner supply position. Each developing unit is provided with an opening for replenishing the toner sent from the toner hopper 118 and a replenishing mechanism, so that the toner can be replenished at the toner replenishing position when the toner runs short.

During operation, the transfer drum 112 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 developing unit 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 on the sheet and meets the sheet.

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.

[0010]

In the above configuration, since the toner hopper is provided on the main body side, a complicated mechanism for supplying toner to the developing unit is required, and the apparatus becomes large and complicated. In addition, the developing unit requires an opening for replenishing toner, so toner spills during toner replenishment not only contaminates the main unit, but also causes spills when replacing the developing unit, making replacement difficult. To Further, the toner supply path from the hopper on the main body side to the developing device becomes long, and the toner may be clogged in the supply path due to the environment or the like, and the toner supply may not be performed normally. Further, in the above configuration, when the image is continuously output in a single color and the toner density is reduced, it is necessary to move the developing device to the toner replenishing position, which hinders the continuous output of the image.

In view of the above problems, an object of the present invention is to provide a color image recording apparatus which is simple and compact in construction of a developing section, does not cause toner spill, and has excellent maintainability.

[0012]

According to a color image recording apparatus of the present invention, a plurality of developing units each having a toner storage portion and a developing roller are assembled in a substantially cylindrical shape with the developing roller always located on the outer peripheral side. The developing unit has a rotating body disposed therein, and the developing unit is configured to be detachably attached to the rotating body from a lid on the upper surface of the apparatus only in a state where an opening near the developing roller is directed upward, and a photosensitive unit is provided at an image forming position. An image, which is arranged to face a body and is developed on a photoconductor by the developing roller, is transferred to recording paper via an intermediate transfer body.

As a result, it is possible to obtain a small and simple developing unit and a color image recording apparatus having good maintainability.

In particular, since the developing unit is operated with the opening disposed upward, the toner can be prevented from spilling from the unit when the unit is replaced. The replacement work can be performed while confirming.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can adopt the following embodiments. The present invention provides an electrostatic image carrier, a plurality of fan-shaped developing units each having a different color developer, and sequentially positioning each of the plurality of developing units at a developing position facing the electrostatic image carrier. Moving means for rotating and moving the substantially circular whole in which the fan-shaped developing unit is combined, and transferring means for sequentially transferring each color toner image developed on the electrostatic image carrier to obtain a color image, A first hopper unit in which each of the developing units stores a developer in which a carrier and a toner are mixed; and a second hopper unit adjacent to the first hopper unit via a toner supply unit and storing only toner Wherein the second hopper in the developing unit is located above the first hopper at the developing position.

Further, according to the present invention, there is provided an electrostatic image carrier, a plurality of developing units each having a developer of a different color, and a plurality of fan-shaped developing units each of which is provided with a developing unit opposing the electrostatic image carrier. Moving means for rotating the whole of the substantially circular shape combined with the fan-shaped developing unit for sequentially positioning the toner image in the position, and sequentially transferring each color toner image developed on the electrostatic image carrier to obtain a color image Transfer means,
A single unit that is attached to the main body in proximity to the outer wall of the developing unit when positioned at the developing position and that can detect the toner concentration of the developer of each color in the developing unit sequentially positioned at the developing position. And a first hopper section in which each of the developing units accommodates a developer in which a carrier and a toner are mixed, and a toner hopper adjacent to the first hopper section via a toner replenishing section to detect only toner. A second hopper section for storing, wherein at least a part of the first hopper and a part of the second hopper are located near a rotation center side of the developing unit. Device.

Further, according to the present invention, there are provided an electrostatic image carrier, a plurality of developing units each having a developer of a different color, and a plurality of fan-shaped developing units each of which is provided with a developing unit opposing the electrostatic image carrier. Moving means for rotating the whole of the substantially circular shape combined by the fan-shaped developing unit in order to sequentially position the toner images, and sequentially transferring the color toner images developed on the electrostatic image carrier to obtain a color image Transfer means,
A single unit that is attached to the main body in proximity to the outer wall of the developing unit when positioned at the developing position and that can detect the toner concentration of the developer of each color in the developing unit sequentially positioned at the developing position. And a first hopper section in which each of the developing units accommodates a developer in which a carrier and a toner are mixed, and a toner hopper adjacent to the first hopper section via a toner replenishing section to detect only toner. A second hopper section for housing, and a means for driving the toner replenishing means in response to a signal from the toner density detecting means is provided on the main body side.

In the above configuration, since the toner hoppers are all contained in the developing units of the respective colors and the toner is not supplied from the outside, the mechanism for supplying the toner is simple, and the toner is spilled when the toner is supplied. And contamination by toner inside the machine is small. In addition, maintenance can be performed simply by replacing the developing units of each color, so that the user can easily perform maintenance. Further, in the above-described configuration, the toner in the toner hopper is configured to accumulate in the toner supply unit in the hopper when the unit is located in the developing position while being naturally stirred when the developing unit is rotationally moved. Therefore, it is not necessary to provide a stirring mechanism, and the configuration of the developing unit can be simplified. Also,
Even when the remaining amount of toner in the hopper becomes small, the toner supply is performed smoothly.

Further, since the toner hopper in the developing unit at the developing position is located above the developer hopper which contains the developer and stirs, the toner can be easily supplied at the developing position. I can do it. Furthermore, since toner density detection and toner replenishment are performed at the developing position, a stable image can be output without lowering the toner density even when a single color is continuously output. Furthermore, in the above configuration, since the developing unit moves, only one toner density sensor whose position is fixed is used for four developing units, so that the configuration of each developing unit is simplified and cost is reduced. It leads to reduction. Furthermore, in the above configuration, since the toner supply is driven on the main body side, there is no need to provide a complicated mechanism for supplying toner on the developing unit side, and the configuration of the developing unit is simplified.

Hereinafter, a color electrophotographic apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of a color electrophotographic apparatus according to an embodiment of the present invention. First, black, yellow, magenta,
4 fan-shaped developing units 1B for each color of cyan
k, 1Y, 1M, and 1C constitute a developing unit group, and are arranged in an annular shape as shown in the figure. Reference numeral 2 denotes a photoreceptor / belt unit, which includes a photoreceptor unit and an intermediate transfer unit. Each developing unit is made of the same constituent members except for a developer to be put in the developing unit. Therefore, for simplification of the description, the developing unit for black will be described, and 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 the black developing unit 1Bk in detail.

In FIG. 2, reference numeral 14a denotes a first hopper containing a developer in which a carrier and a toner are mixed, and 14b
Is a second hopper containing only toner, 15 is an opening opened for toner supply, 16 is a lid for opening and closing the opening 15, and 17 is an agitator for toner supply, 18a and 18b. Reference numeral denotes an agitator for transporting the developer in the first hopper 14a to the developing portion.

Reference numeral 19 denotes a rotatable developing electrode roller made of aluminum; 20, a non-rotating magnet coaxially fixed inside; 21, 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 electrode roller 19 has a diameter of 1
It was rotated in the direction of the arrow at a peripheral speed of 60 mm / s at 6 mm.

In the first hopper 14a, 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 electrode roller 19 by conveyance by the agitators 18a and 18b and magnetic force. The toner used is obtained by dispersing a pigment or the like in a polyester resin and further adding an additive. The developer 26BK attached to the electrode roller 19 is transported to a developing site in a state where the layer is regulated by the blade 22, and is used for development.

In the second hopper 14b, 400 g of toner is hermetically stored at the time of assembling the developing unit, and it is possible to output 5,000 originals corresponding to 5% A4 single color without replenishing toner from outside the unit. I have. When the toner in the second hopper 14b runs out, the user only needs to replace the developing unit.

The developing unit shown in FIG. 2 is a black developing unit and also shows the vertical position of the developing unit at the developing position. In the figure, since the developer second hopper 14b containing the toner 25Bk is located above the first hopper 14a, the unit can be provided inside the toner hopper 14b without providing a feed mechanism or a stirring mechanism for moving the toner. The toner is supplied to the vicinity of the opening 15 by the rotational movement and the weight of the toner, and the toner can be smoothly supplied.

Reference numeral 28 denotes a cover for protecting the electrode roller 19, and FIG. 2 shows a state opened for development. When the developing unit is located at a position other than the developing position, the cover 28 holds the electrode roller 1 carrying the developer.
9 to prevent contamination due to developer dust and the like and contamination inside the apparatus due to toner when the unit rotates.

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

Referring again to FIG. 1, the configuration of the printer unit will be described. Reference numeral 9 denotes an organic photoreceptor in which phthalocyanine is dispersed in a polycarbonate-based binder resin, 10 denotes a charging roller for negatively charging the photoreceptor, 13 denotes a signal beam by a laser beam, and 27 denotes cleaning of toner remaining on the photoreceptor surface after transfer. It is a cleaner. Developing units 1Bk, 1Y, 1M, and 1C arranged in a ring form a support (not shown).
As a whole, is driven by a moving motor 30 as a moving means controlled by a control circuit 29, and is rotatable in a direction indicated by an arrow around a cylindrical fixed and non-rotating shaft 31. . Each developing unit is sequentially moved to a developing position 50 facing the photoconductor 9. The support of the developing units 1BK, 1Y, 1M, and 1C has a means (not shown) for detecting that each developing unit has moved to the developing position 50. Each time the movement of each unit is completed, the movement is completed. The corresponding signal is transmitted to the control circuit 29.

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.
And irradiates the photosensitive member 9 to form a latent image.

Numeral 60 denotes a magnetoresistive toner concentration sensor installed on the shaft 31 so that the toner concentration in the first hopper 14a of the developing unit can be detected when the developing unit is moved to the developing position 50. ing. The thickness of the side wall of the developing unit corresponding to the position of the toner density sensor 60 is set thin so that the toner density can be stably detected. Further, in order to further stabilize the detection, the side wall of the unit corresponding to this sensor may be changed to a material having good smoothness and strength even though it is thin. In this embodiment, the toner concentration sensor 60 is fixed without using the separation / contact mechanism, but the position of the toner concentration sensor 60 is slightly shifted to the inside of the rotation when the unit is rotated using the separation / contact mechanism. A configuration in which a separation / contact mechanism may be used, or a configuration in which a spring member or the like is used to press against the side wall of the unit from behind may be used. Further, in this embodiment, the toner density sensor 60 is of a magnetoresistive type. However, for this sensor, for example, an optical reflection density sensor or the like may be used in which the corresponding side wall of the developing unit is transparent. Needless to say.

Next, the operation of the printer will be described with reference to FIG. The diameter of the photoconductor 9 is 30 mm, and the peripheral speed is 60 mm /
s rotated in the direction of the arrow.

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.

Next, the surface of the photoreceptor 9 is set to 400
Developer 2 in a state where layers are opposed and spaced apart by μm
It passed in front of the electrode roller 19 carrying 6BK. When the photosensitive member 9 passes through the uncharged area, an AC high voltage power supply 21 applies a 750 V0-p (1.5 kV peak-to-peak) AC voltage (frequency 1 kHz) superimposed on the electrode roller 19 to the electrode roller 19. Applied. Then, -7
When passing through the surface of the photoreceptor 9 charged with the electrostatic latent image and charged to 00 V, the electrode roller 19 is superposed by a high voltage power supply 21 on which a DC voltage of -400 V is superimposed. 5 kV) AC voltage (frequency 1.5 kHz) was applied. As a result, a negative-positive inverted toner image was left only on the image portion on the photoconductor 9. The carrier and the toner attached to the electrode roller 19 rotating in the direction of the arrow are returned to the developer first hopper 14a again and used for the next development.

Thus, a black toner image is obtained on the photoreceptor 9. Reference numeral 32 denotes an intermediate transfer belt, which is an endless belt-like semiconductive urethane film having a thickness of 100 μm, and a transfer roller 33 and a stainless steel roller 34 around which are formed a urethane foam having a low resistance treatment. And can be moved in the direction of the arrow.

The transfer roller 33 is lightly pressed against the photosensitive member 9 via the intermediate transfer belt 32. The transfer roller 33 is connected to the roller 34 via the intermediate transfer belt 32.
A second transfer roller 35 having the same configuration as described above is lightly pressed so as to be able to be driven and rotated.

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 40 denotes a belt cleaner section including a belt cleaner for cleaning the intermediate transfer belt. The waste toner collected by the belt cleaner 40 is sent to the photoconductor cleaner 27 via a waste toner conveying pipe 37.

The photoreceptor / belt unit 2 includes a photoreceptor 9,
Charging roller 10, photoreceptor cleaner 27, intermediate transfer belt 32, transfer roller 33, roller 34, waste toner conveying pipe 3
7, and the structure including the belt cleaner portion 40 allows easy replacement.

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

The above is the description of the main structure of the electrophotographic apparatus and the developing unit of the present invention. Next, the operation of this apparatus during color development will be described.

First, each developing unit is located at a position as shown in FIG. 1, the developing unit 1Bk for black is located at a developing position 50 facing the photoreceptor 9, and a toner density is provided on a side wall of the developing unit. The sensor 60 is positioned so as to be almost in contact as shown. Black signal light is input to the photoconductor 9 by the laser exposure device 3, and development with black toner is performed. At the same time as the development is started, the toner concentration sensor 60 starts detecting the toner concentration of the developer in the first hopper 14a,
The toner supply is performed according to the detection signal.

FIG. 3 shows a driving section of the toner supply agitator 17 of the unit under development. 70 is a gear for rotating the agitator 17, and 71 is a gear 7 provided on the main body side.
The reference numeral 72 denotes a motor for driving 0, and 72 denotes a gear for transmitting the drive of the motor 71 to the gear 70. When replenishing toner in accordance with the output of the toner density sensor 60, the motor 71 rotates, the driving force is transmitted to the agitator 17 via the gear 72 and the gear 70, and the agitator 17 rotates, and the inside of the second hopper 14b Is supplied into the first hopper 14a. When the developing unit group is rotationally moved, the gear 72 is separated from the gear 70, and can be connected when the movement of the unit group is completed. In the present embodiment, a motor for supplying toner is newly provided on the main body side. However, the drive may be transmitted from a driving unit provided on the main body side for another purpose, such as a motor for driving a photoconductor. . In this case, the drive control of the agitator 17 can be easily performed by providing a drive separation / contact means such as a clutch during the transmission of the drive.

As shown in FIG. 2, the lid 16 in the developing unit is rotatably fixed to one side by a hinge so as to open only when a force is applied from the second hopper 14b side, and is opened when no force is applied. A torsion spring (not shown) is attached to close the part 15. In addition, the agitator 17 is configured to push open the lid 16 while stirring the surrounding toner to supply the toner. With this configuration, toner replenishment is performed according to a signal from the toner density sensor 60. Actually, the toner density detection is started three seconds after the start of the development so that the detection of the toner density can be performed after the output of the sensor is stabilized. Agitator 17 when toner supply is not performed
Is stopped at a position where the lid 16 cannot be pushed open. In addition, when the developing unit is not developing, especially when the developing unit is moved to a place other than the developing position, the lid 16 is provided with a lock mechanism (not shown) provided on a support (not shown) of the developing unit. (Not shown) to prevent the toner from being mixed into the first hopper from the second hopper except at the time of toner replenishment.

The black toner image developed on the photosensitive member 9 is sequentially transferred onto the intermediate transfer belt 32 by the action of the transfer roller 33.

Developing unit group 1Bk, 1Y, 1M, 1C
The whole is driven by the movement motor 30 to rotate integrally in the direction of the arrow in FIG. 1 and stops at the position where the developing unit 1Y reaches the developing position 50 by just rotating by 90 degrees, and the developing unit 1Y is positioned. . Since the portion other than the electrode roller 19 of the developing unit is located inside the rotating arc at the tip of the electrode roller 19, the photoconductor 9 does not contact the developing unit. Also, the cover 28 of the electrode roller 19
Each of the developing units is opened according to the movement before being positioned at the developing position 50 and can be stored in the developing unit as shown in FIG. 2, and is closed again when the movement is completed after the development is completed. As before, the laser exposure device inputs signal light to the developing unit 1Y using the yellow signal, 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 cleaner section 40 are slightly separated from the intermediate transfer belt, and do not act on the toner image thereon.

The same operation as described above is performed for magenta and cyan, and the four color toner images are superimposed on the intermediate transfer belt in a position-matched 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 and prepared for the next development.

Next, the operation in the monochrome mode will be described. In the single color mode, first, a developing unit of a predetermined color is moved to a developing position and positioned. Next, development of a predetermined color and transfer to the intermediate transfer belt are performed in the same manner as before, and this time, the transfer is continued as it is, and then transferred to the sheet sent from the sheet supply unit by the next second transfer roller. To go.

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 developing 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 developing unit of the target color is moved to the upper position (the developing unit in FIG. 1). 1C). Then, as shown in FIG. 3, the operator opens the cover 46 located at the upper part of the apparatus main body, takes out only the developing unit of interest from the outside of the apparatus, and mounts a new developing unit of that color.

At this time, since the electrode roller cover is in the closed state, the worker does not stain his hands with the developer or spills the developer.

Further, since the developing unit to be replaced can be replaced at an upper position different from the developing position, the developing unit can be easily taken out of the apparatus because it is not disturbed by the related members such as the transfer portion and is not positioned. And maintainability is excellent.

For the photoreceptor / belt unit 2, the operator is notified of the replacement time by displaying on the panel of the main body that the life of the unit has expired. The operator opens the front door 47 based on this display, removes the used photoconductor / belt unit 2, and mounts a new unit. 4
Reference numeral 8 denotes a shutter that covers a portion where the photoconductor 9 of the photoconductor / belt unit 2 contacts the electrode roller 19 of the developing unit.
Reference numeral 9 denotes a shutter that covers a portion where the belt 32 of the photoreceptor / belt unit contacts the second transfer roller 35.
Reference numeral 9 denotes a configuration in which the front door 47 is opened, and the shutter 48 closes when the photoconductor / belt unit is removed from the main body. Thereby, the operator can replace the photoconductor / belt unit 2 without touching the intermediate transfer belt and without spilling waste toner.

The above is the description of the configuration and operation of the embodiment.
In this configuration, the intermediate transfer member is used. However, the essence and the function and effect of the present invention are not changed even when a transfer method such as a transfer drum method in which paper is wound directly onto paper is used.

In the above-described embodiment, a specific developing method is used for the developing unit. However, if a method of mixing a carrier and a toner is used, a developing unit having a structure using another developing method may be used. However, the essence and effect of the present invention do not change.

[0055]

As described above, according to the present invention, the developing units are completed independently as one developing unit for each color, and the structure is simplified without requiring a complicated toner supply mechanism. Further, the photoconductor unit and the intermediate transfer belt unit are also unitized, so that the user only has to replace the developing unit and the photoconductor belt unit of each color, and the maintenance property is excellent.

In addition, each developing unit is configured so that toner can be easily replenished, and only one toner concentration sensor and toner replenishing mechanism need to be mounted on the main body for each of the four developing units. The configuration is simplified.

Since the size of the intermediate transfer member can be reduced, the size of the apparatus can be reduced.

[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 a developing unit used in the color electrophotographic apparatus according to the embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating transmission of driving of a toner supply unit according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram when the developing unit and the photoconductor / belt unit are replaced.

FIG. 5 is a configuration diagram of a conventional color electrophotographic apparatus.

[Explanation of symbols]

 1Bk, 1C, 1M, 1Y Developing unit 2 Photoreceptor / belt unit 3 Laser exposure device 9 Photoreceptor 13 Signal light 28 Electrode roller cover 32 Intermediate transfer belt 33 Transfer roller 35 Second transfer roller 50 Developing position 60 Toner density sensor

Continuation of the front page (56) References JP-A-60-208779 (JP, A) JP-A-63-177165 (JP, A) JP-A-62-163071 (JP, A) JP-A-5-249795 (JP) JP-A-4-43374 (JP, A) JP-A-6-138744 (JP, A) JP-A-6-110261 (JP, A) JP-A-4-318875 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 15/08-15/095 G03G 15/16

Claims (2)

(57) [Claims] 1. A plurality of developing units each having a toner container and a developing roller include a rotating body that is collectively arranged in a substantially cylindrical shape in a state where the developing rollers are always located on the outer peripheral side. Only when the opening in the vicinity of the developing roller is directed upward, it is detachably attached to the rotating body from the lid on the upper surface of the apparatus, and at the image forming position,
A color image recording apparatus, which is arranged to face a unitized photoreceptor, and transfers an image developed on the photoreceptor by the developing roller to recording paper via an intermediate transfer member. 2. A developing unit for use in the color image recording apparatus according to claim 1, wherein the developing unit contains color toner therein, and is detachably attached to a rotating body with the developing roller facing upward. A developing unit.