JPH07234575A - Carrier replenishing method for two-component developing device and the same device - Google Patents

Abstract

(57) [Abstract] [Objective] A carrier replenishing method for a two-component developing device, which enables downsizing of the device and cost reduction by commonly using carrier replenishing means for a plurality of developing devices, and To provide a carrier supply device. [Structure] The carrier replenishment method is based on a plurality of developing devices 4, 1.
One carrier replenishing means 22 is provided, and the carrier replenishing means 22 is commonly used to replenish the carrier to each developing device 4. The carrier replenishing device includes a plurality of developing devices 4D, one carrier replenishing means 40, and a revolver portion 27d that supports the developing device 4D. The carrier replenishing means 40 is attached integrally with the developing device 4D, and the carrier replenishing means 40 is attached to the developing device. It is characterized in that it is configured to rotate in conjunction with the movement of 4D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-component developing device used in an image forming apparatus such as a color electrophotographic copying machine, a facsimile, and a color laser beam printer.
More specifically, the present invention relates to a carrier replenishment method for supplying a carrier of a two-component developer in a developing device into the developing device when the carrier is replaced.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus adopting an electrostatic recording system, an electrostatic latent image corresponding to an original image is formed on a photoconductor surface, and the electrostatic latent image is visualized by a developing device containing a developer. An image is formed by transferring the image to a transfer paper and fixing it. As shown in FIG. 8, a copying machine, which is one of the image forming apparatuses, has a photoconductor drum 1 (for example, an organic photoconductor: OPC) which is a latent image carrier at approximately the center of a base frame (not shown).
And the drum 1 is rotatably mounted around a rotation axis (not shown) perpendicular to the plane of the drawing. A document placing surface on which a document is placed is provided above the photoconductor drum 1. The document image on the document placing surface is read as an image signal by a well-known image reading element (not shown), and the read image signal is digital. The image is processed, image-processed, and sent to a known optical writing unit 3.
The optical writing unit 3 is composed of a polygon mirror and a laser diode (not shown), and is driven based on the above-mentioned image-processed signal, and optical writing is performed on the photosensitive drum 1 by laser light. At this time, the charging charger 2 has already been
Thus, an electrostatic latent image is formed on the surface of the photosensitive drum 1 that is uniformly charged.

This electrostatic latent image is made into a visible image by a two-component developing device 4 provided opposite to the side of the photosensitive drum 1, and this visible image is transferred from a paper feeding section 5. It is transferred to the paper by the corona discharge of the transfer charger 6. After this transfer, the transfer paper is separated from the surface of the photoconductor drum 1 by a separation charger (not shown), the transfer image on the transfer paper is fixed by a fixing unit (not shown), and then the paper is discharged to a paper discharge tray (not shown) outside the base frame. The toner remaining on the surface of the photosensitive drum 1 after the transfer is removed by the cleaning device 7.
Are removed by. The developer used in this developing device is a one-component developer capable of directly supplying a charged toner to the surface of the photoconductor to visualize an electrostatic latent image, and a toner which is attracted to the surface of a carrier by frictional charging and is There is known a two-component developer that can supply a carrier to the surface of a photoconductor to visualize an electrostatic latent image.

The toner used in this developing device is repeatedly supplied to the surface of the photosensitive member and consumed until it is utilized for visualizing. The carrier in the two-component developer adsorbs toner on its surface by frictional charging, the carrier with the toner is supplied to the photoconductor surface, and the electrostatic latent image on the photoconductor surface attracts the toner from the carrier to electrostatically charge it. The latent image has been developed. When the carrier of such a two-component developer approaches the use limit, in most cases, it causes poor charging and deteriorates. If such a charging failure occurs,
Since an abnormal image or the like is generated due to toner scattering due to excessive toner, carrier replacement or developer replacement is performed at appropriate times.

For example, Japanese Laid-Open Patent Publication No. 53-22747 discloses a single developing device. As shown in FIG. 9, the apparatus includes carrier replenishing means for replenishing carriers independently. The carrier 11 stored in the carrier cartridge 9 which is the carrier replenishing means is conveyed to the developer stirring section 15 in the developing container 14 by the conveying force of the auger 12 driven by the motor MA and the auger 13 driven by the motor MB. The deteriorated carrier is discarded by the auger 19 driven by the motor MC through the developer recovery port 16 provided near the powder surface of the stirring unit 15. The toner is replenished little by little from the toner cartridge 10 by the toner replenishing roller 17. The amount of carrier replenished is appropriately controlled by the amount of recovery of the auger 12, and the toner concentration in the developer stirring unit 15 is made substantially constant by the controller 18 according to the amount of toner consumed for image formation, the amount of toner replenished, and the amount of carrier discarded. To be kept.

As described above, in this developing device,
A certain amount of the carrier 11 is supplied to the developer in the developing container 14, the same amount of the developer in the developing container is discharged to the developer waste container 20, and a part of the deteriorated carrier is replaced. . Further, in this developing device, the amount of the developer in the developing container is constantly detected by the volume detecting means 21, and when the toner is consumed and the amount of the developer in the developing container decreases by a predetermined amount, the toner is supplied. I am trying to do it. Japanese Unexamined Patent Publication (Kokai) No. 61-117575 discloses an electrophotographic copying machine, a color recording device for a computer, and the like.
Disclosed is a dry type rotary developing device for color or monochromatic color of three or more colors, so-called multicolor or full color. The dry type rotary developing device adopting this revolver system is yellow,
Magenta, cyan, and black developing units are integrally housed in a rotating body. Further, each toner from the toner replenishing device is supplied to each developing unit into each developing unit through the hollow shaft of the rotating body, the toner is stirred with the carrier in each developing unit, and then the developing roller in each developing unit. When the developing unit for each color is rotationally moved to the developing position, the electrostatic latent image corresponding to each color is developed to obtain a visible image.

[0007]

If the single developing device as described above is applied to a color image forming apparatus, two to four sets of similar developing devices are prepared for each color. If the replenishing means is mounted on each developing device, it will be very large, and it is easily expected that the cost will be greatly increased. On the other hand, in the revolver type color developing device as described above, there is disclosed a toner replenishing method capable of replenishing toner without causing color mixture during development by the developing units of a plurality of colors. However, regarding the carrier in each developing unit of this color developing device, there is no disclosure about replenishment, and in this case, it is presumed that a service person will collectively discard used developer and replenish it. It

It is desired to eliminate the need for such carrier replacement work by a service person and reduce the cost and time required for maintenance work.

In order to meet this requirement, a plurality of the above-mentioned single developing devices having means for storing carriers in the device and automatically replacing a part or all of the carriers are installed in parallel in a color developing device. It may be incorporated. However, when such a conventional developing device capable of automatically exchanging carriers is applied to a color developing device having a plurality of developing devices, the size of the device becomes very large and the cost increases. The present invention has been made in view of the above problems, and a first object of the present invention is to reduce the size of an apparatus by commonly using carrier replenishing means for a plurality of developing apparatuses. It is an object of the present invention to provide a carrier replenishing method for a two-component developing device, which enables cost reduction and cost reduction. The second and third objects are two components that can reduce the size and cost of the device by moving the developing device or the carrier replenishing means to a common carrier replenishable position and then performing the carrier replenishing operation. Another object of the present invention is to provide a carrier replenishing method for a developing device.

A fourth object of the present invention is to provide a carrier replenishing device for a two-component developing device capable of interlocking the carrier replenishing means with the developing device so as to charge the carrier and then supply it to minimize image deterioration. To provide. A fifth object is to provide a carrier replenishing device for a two-component developing device that can quantify the amount of replenishing the carrier and obtain a stable image. A sixth object of the present invention is to provide a carrier replenishing method for a two-component developing device in which toner corresponding to each developing device is prevented from being mixed by intervening carrier replenishing means and no color mixture of toner occurs.

[0011]

In order to achieve the above object, in the method invention of claim 1, a plurality of developing devices and one carrier replenishing means are provided, and carrier replenishment for each developing device is performed by the carrier replenishing. It is characterized in that it is commonly performed by means.

According to a second aspect of the present invention, a plurality of developing devices can be moved to a common carrier replenishable position corresponding to the carrier replenishing means, and the developing device for replenishing the carrier is placed at the carrier replenishable position. After moving,
It is characterized by performing a carrier supply operation. Claim 3
In the method invention of claim 1, in the carrier replenishing method according to claim 1, the carrier replenishing means is configured to be movable to a carrier replenishable position of each developing device, and the carrier replenishing means is adapted to the carrier replenishing device. After moving to the possible position, the carrier replenishing operation is performed.

According to the invention of claim 4, a plurality of developing devices, 1
One carrier replenishing means and a revolver type developing device moving means for supporting the developing device are provided, the carrier replenishing means is attached integrally with the developing device, and the carrier replenishing means is configured to rotate in association with the movement of the developing device. It is characterized by According to a fifth aspect of the invention, in the carrier replenishing device according to the fourth aspect, a pumping means for pumping the carrier in a fixed amount according to the rotation is provided inside the carrier replenishing means,
It is characterized in that the carrier replenishment amount is quantified by the pumping means. According to a sixth aspect of the present invention, in the carrier replenishing device according to the fourth aspect, a powder conveying means for mixing and conveying the carrier and the toner is provided, and a carrier replenishing point is arranged on the upstream side of the flow path of the powder conveying means. It is characterized in that the toner supply point is arranged on the downstream side.

[0014]

According to the first aspect of the present invention, the carrier replenishing means is commonly used for replenishing the carrier to each developing device, so that the carrier replenishing means in the developing device used here can be simplified and downsized. According to the second aspect, the carrier replenishing operation is performed after the developing device for replenishing the carrier is moved to the position where the carrier can be replenished. Therefore, the carrier conveying path in the developing device used here can be simplified and downsized easily. Become. According to the third aspect, since the carrier replenishing operation is performed after the carrier replenishing means is moved to the carrier replenishable position corresponding to the developing device for replenishing the carrier, the carrier conveying path in the developing device used here is simplified. , Easy to miniaturize.

According to the present invention, a plurality of developing devices, one carrier replenishing means, and a revolver type developing device moving means for supporting the developing device are provided, and the carrier replenishing means is attached integrally with the developing device. Is rotated in conjunction with the movement of the developing device, it is possible to precharge the carrier before replenishment and then replenish the carrier.
According to claim 5, in the carrier replenishing device according to claim 4, since the carrier replenishing means is provided with the pumping means for pumping the carrier quantitatively according to the rotation, the carrier replenishing amount is quantified by the pumping means. Therefore, it becomes possible to supply a fixed amount of carrier accurately and stably. According to a sixth aspect of the present invention, in the carrier replenishing device according to the fourth aspect, the powder replenishing means for mixing and conveying the carrier and the toner is provided, and the replenishment point of the carrier is arranged upstream of the flow path of the powder replenishing means. Since the replenishment point is disposed on the downstream side, it is possible to prevent the toner corresponding to each developing device from being mixed by the interposition of the carrier replenishing means.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a carrier replenishing device of a two-component developing device used in the developing method of claim 1. This apparatus may be installed in a copying machine as an image forming apparatus as shown in FIG. 2, and can be applied to other full-color image forming apparatuses such as an electrophotographic system and an electrostatic recording system such as a printer. Here, first, the carrier replenishing device of the two-component developing device (hereinafter simply referred to as developing device) 4A shown in FIG. 1 will be described. The copying machine in this example separately forms electrostatic latent images of four colors of cyan, magenta, yellow, and black.
One photosensitive drum 1a and a transfer belt 8 that circulates so as to sequentially face the four photosensitive drums 1a arranged in series are arranged in a base frame (not shown). Here, the means for image formation as described with reference to FIG. 8 is similarly arranged in the vicinity of the outer periphery of each of the photosensitive drums 1a, but redundant description will be omitted here.

On the photosensitive drum 1a, color-specific original images obtained by color-separating original images are read by an image reading device (not shown), and the read image signals are sent to an optical writing unit (not shown) for optical writing. The unit is driven based on an image signal, and optical writing is performed on the photosensitive drum 1a, so that electrostatic latent images of different colors are formed on the surface of the photosensitive drum 1a. Each electrostatic latent image on each photoconductor drum 1a is visualized by each color-specific developing device 4A provided on the side of the photoconductor drum 1a, and the visible image for each color is transferred to the transfer belt 8. The images are transferred one on top of the other, transferred onto a transfer paper (not shown), and the transfer image on the transfer paper is fixed to form a full-color image. The developing device 4A for each color is a toner hopper 20C.
20M, 20Y, 20Bk and toner replenishing rollers 21C, 21M, 21Y, 21Bk below each toner hopper
Each developing device 23 is replenished with toner and also replenished with a common carrier by a single carrier replenishing means 22.
Equipped with C23M23Y23Bk. Each developing device 2
3C, 23M, 23Y, and 23Bk stir the supplied toner and carrier to develop rollers 24C, 24M, and 24Y.
・ It circulates and supplies it to 24Bk, and the same roller is used for each photosensitive drum 1.
The electrostatic latent image for each color on the surface of a is visualized.

The carrier replenishing means 22 branches the single carrier cartridge 25 and the carrier of the carrier cartridge 25 into respective developing devices 23Y, 23M, 23C and 23B.
Auger 26C / 26M / 26Y / 2 to be individually transported to k
6Bk. Each auger rotatably drives the screw by a carrier / toner supply motor (not shown) to supply the carrier in an amount corresponding to the amount of rotation. In addition, each developing device 2
3C, 23M, 23Y, and 23Bk are carrier replenishing means 2
At the same time, the carrier is replenished from the carrier 2, and the deteriorated carrier is sequentially discharged from the developer recovery port (not shown) in an amount corresponding to the overflow. Each developing device 23C
The usage ratios of the 23M, 23Y, and 23Bk carriers are not constant, and their supply amounts are not the same. here,
Control means (not shown) are the developing devices 23C, 23M, 23Y.
The usage ratio of the 23 Bk developer is obtained, the rotation amount of each auger corresponding to each usage ratio is calculated, and each auger 26C, 26M, 26Y, 26Bk is driven by the respective rotation amount.

As described above, a plurality of the developing devices 4A of FIG. 1 are provided for each color of cyan, magenta, yellow and black, and one carrier replenishing means 22 is provided opposite thereto, and these developing devices 4A are used. According to all development methods,
The common carrier replenishing means 2 does not need to replenish the respective developing devices 4A with independent carrier replenishing means.
2 can be carried out without excess or deficiency, and in particular, since only one carrier cartridge 25 is provided, only one carrier cartridge needs to be replaced and the operability is excellent. It should be noted that the storage amount of the carrier may be expanded to the extent that it can withstand the life of the apparatus, cartridge replacement may be abolished, and maintenance may be omitted. FIG. 2 shows a developing device 4B used in the developing method of claim 2.

The developing device 4B adopts a revolver developing system and is provided with a revolver portion 27 as a developing device moving means. The revolver portion 27 is sequentially rotated around its rotation center line 271 (a line perpendicular to the paper surface in FIG. 2). Formed possible,
Cyan, magenta, yellow,
The developing device 4B for each color of black is integrally mounted. Each developing device 4B basically has the same structure,
Developing devices 28C, 28M, 28Y, 28Bk for each color,
Developing chambers 29C / 29M / 29Y / 29B inside them
k, the developing rollers 30C, 30M, 30Y, and 30Bk fitted into the windows on the outer peripheral wall side of each developing chamber, and the shutters 31 which are arranged in the vicinity of the windows on the outer peripheral wall side of each developing chamber. It is configured with each carrier supply port 32.

Here, the developing device rollers 30C, 30M, 30Y, and 30B in the developing device supported by the revolver unit 27 are provided.
k is sequentially applied to the developing position P1 facing the photosensitive drum 1b,
By rotating and moving, an electrostatic latent image corresponding to each color is developed.
Here, a color-specific electrostatic latent image corresponding to the color-specific image obtained by color-separating the original image is sequentially formed on the photosensitive drum 1b for each rotation, and the color-specific electrostatic latent image of the revolver unit 27 is formed. The image is developed by the developing device rollers 30C, 30M, 30Y, and 30Bk for each color, which are switched to the developing position P1 for each quarter rotation, and the visible image for each color obtained by this is transferred to the transfer belt 8.
Are sequentially superposed and transferred onto a transfer sheet (not shown), the transfer image on the transfer sheet is fixed, and a full-color image is formed.

Here, the developing devices 28C, 28M, 28Y
28Bk sets each carrier supply port 32 to the carrier supply possible position P2 when reaching the uppermost position. At this time, the shutter 31 is opened by the action of an opening / closing lever driven by a solenoid (not shown), and is normally closed by elastic force. The shutter 31 may be opened only at the time of replenishment by a cam mechanism or the like (not shown) that is interlocked with the rotation of the revolver unit 27. Immediately above the carrier supply port 32 at the carrier supply possible position P2, a fixed carrier replenishing means 22b is provided opposite thereto. The carrier replenishing means 22b includes a single carrier cartridge 25b and the developing devices 28C and 28M which have reached the carrier supply position P2 for the carrier of the carrier cartridge 25b.
・ Carrier replenishing roller 3 that can replenish 28Y ・ 28Bk
3 and 3.

The carrier replenishing roller 33 is rotationally driven by a carrier supply motor (not shown) to supply the carrier in an amount corresponding to the amount of rotation. In addition, each developing device 28C / 28
To the M, 28Y and 28Bk, toner supply means (not shown) (which may be a toner cartridge shown in FIG. 4, which will be described later) is attached to the M, 28Y and 28Bk.・ 28 Bk
Supplied within. Here, the control means (not shown) obtains the usage ratio of the developer of each of the developing devices 28C, 28M, 28Y, and 28Bk, and drives the carrier replenishing roller 33 and the toner supply means (not shown) in accordance with each usage ratio, for each color. Each toner and carrier replenishment amount is controlled. As described above, the developing device 4B of FIG. 2 is provided for each color of cyan, magenta, yellow and black, and one carrier replenishing means 22b is provided opposite to the plurality of developing devices 4B. In particular, each developing device 4B has a carrier replenishing means 2
It is configured to be movable to a common carrier replenishable position P2 corresponding to 2b.

In the developing method using such an apparatus,
After moving the developing device 4B for the purpose of carrier replenishment to the carrier replenishment possible position P2, the carrier replenishing means 22
The carrier is replenished by b. Therefore, one carrier replenishing means 22b only needs to replenish the carrier to each developing device 4B which has reached the carrier supply possible position P2, and the carrier supply operation is simplified. Particularly, in the device used here, it is shown in FIG. Since the augers 26C, 26M, 26Y, and 26Bk as the carrier transporting means are not required, the apparatus can be greatly simplified, and the size and cost can be easily reduced.

FIG. 3 shows a developing device 4C used in the developing method of claim 3. This apparatus may be installed in a copying machine as an image forming apparatus, and can be applied to other full-color image forming apparatuses such as an electrophotographic system and an electrostatic recording system such as a printer. The developing device 4C in this example forms electrostatic latent images of four colors of cyan, magenta, yellow, and black separately, and also forms four photosensitive drums 1c and four photosensitive drums 1c arranged in series. A transfer belt 8c, which circulates so as to sequentially face each other, is arranged in a base frame (not shown). Here, a color-specific original image obtained by color-separating the original image is read by an image reading device (not shown), the read image signal is sent to an optical writing unit (not shown), and the optical writing unit is driven based on the image signal. Then, optical writing is performed on each photoconductor drum 1c, and a color-specific electrostatic latent image is formed on the surface of the photoconductor drum 1c. Each electrostatic latent image on each photoconductor drum 1c is visualized by each color-specific developing device 4C provided on the side of the photoconductor drum 1c, and the color-visible image is transferred to the transfer belt 8c. The images are transferred one on top of the other, transferred onto the transfer paper from the paper feed unit, and the transfer image on the transfer paper is fixed to form a full-color image.

The developing device 4C for each color includes a toner hopper 20.
C, 20M, 20Y, 20Bk and toner replenishing rollers 21C, 21M, 21Y, 21 under each toner hopper
Developers 23C / 23M / 2 with toner supplied from Bk
3C ・ 23Bk and each developing device 23C ・ 23M ・ 23Y ・
23Bk is provided with a single carrier replenishing means 22c. Each developing device 23C, 23M, 2
3Y · 23Bk agitates the supplied toner and carrier and circulates them to the developing rollers 24C · 24M · 24Y · 24Bk, and the rollers form a visible image of the electrostatic latent image of each color on the surface of each photosensitive drum 1c. Turn into. The carrier replenishing means 22c is composed of a single carrier cartridge 25c and a horizontal moving device M1 for moving the cartridge horizontally. The horizontal moving device M1 is a carrier cartridge 25c.
Rail 34 and feed screw 35 for sequentially guiding the developing devices 23C, 23M, 23Y, 23Bk to the carrier supply ports 32c, a carrier cartridge moving motor 36 for driving the feed screw 35, and a drive control for the moving motor 36. Control means that does not.

A carrier replenishing roller 37 is provided below the carrier cartridge 25c, and the roller is rotationally driven by a carrier supply motor (not shown) to supply the carrier in an amount corresponding to the amount of rotation. In addition, each developing device 23C
・ 23M ・ 23Y ・ 23Bk are carrier replenishing means 22c
As the carrier is replenished, the deteriorated carrier overflow is discharged from a developer recovery port (not shown). Each developing device 23C, 23M, 23Y, 23B
The carrier supply port 32c of k is arranged at each carrier supply possible position P2, is normally closed by the shutter 31c, and when the supply port of the carrier cartridge 25c faces each other, it is operated by an opening / closing lever driven by a solenoid (not shown). It is configured to be opened.
In addition, the shutter 31 is provided only at the time of replenishment by a cam mechanism or the like (not shown) that is interlocked with the movement of the carrier cartridge 25c.
You may open c.

As described above, the developing device 4C of FIG. 3 is provided for each color of cyan, magenta, yellow, and black.
One carrier replenishing means 2 is provided to the plurality of developing devices 4C.
2c is installed opposite. In particular, the carrier replenishing means 22c for replenishing the carrier is configured to be driven by the horizontal moving device M1 so as to be movable to the carrier replenishable position P2 of each developing device 4C. In the developing method using such an apparatus,
Carrier cartridge 25c of carrier replenishing means 22c
Is moved to the carrier replenishable position P2 of the developing device 4C for the purpose of replenishing the carrier, and then the carrier replenishing operation is performed. Therefore, the common carrier replenishing means 22c can be used to replenish the carriers to the respective developing devices 4C without using independent carrier replenishing means. In particular, since only one carrier cartridge 25c is provided, one carrier cartridge 25c can be provided. It is easy to replace the carrier cartridge and has excellent operability. Furthermore, here, the auger 2 in FIG.
By removing the 6C / 26M / 26C / 26Bk and adding a low-priced and highly reliable horizontal moving device M1, a considerable function can be secured.

FIG. 4 shows a developing device 4D as an embodiment corresponding to claims 4, 5 and 6. This developing device 4D adopts a revolver developing system, is provided with a revolver portion 27d as a developing device moving means, and is formed so that the revolver portion 27d can be sequentially rotated around its rotation center line 271. The revolver portion 27d is provided with cyan magenta. The developing device 4D for each color of yellow and black is integrally mounted. Each developing device 4D basically has the same structure, and in particular,
The revolver portion 27d has a carrier cartridge 4 as carrier replenishing means in the longitudinal direction of the rotation center line 271.
0, toner cartridge 41 and developing device 42C / 42M
・ 42Y and 42Bk (see Fig. 7) are integrally mounted in this order.

As shown in FIG. 5, the carrier cartridge 40 has a cylindrical shape, and a predetermined amount of carrier is retained at the bottom of the carrier cartridge 40. When the carrier cartridge 40 rotates, these carriers are stirred and charged. The carrier cartridge 40 has four hoppers 43C, 43M, 43Y, and 43Bk inside thereof at equal intervals along the rotation direction.
And four stoppers 44 in the shape of a curved plate, which are arranged at the portions facing the openings of the respective hoppers, and these protrude from the inner wall of the carrier cartridge 40. In addition, a normally-closed port for supplying the carrier at a proper time is formed on a part of the outer wall of the carrier cartridge 40, and the carrier is replenished into the carrier cartridge 40 at the time of maintenance.

When the carrier cartridge 40 is rotated, the stoppers 44 scrape up the low-position carrier, and the hoppers 43C, 43M, and 43Y are opposed to each other as the carrier 44 rotates.
-Supply to the carrier holding area of 43 Bk. Each hopper 4
When 3C, 43M, 43Y, and 43Bk sequentially reach near the front and rear of the carrier supply possible position P2 which is the highest position,
Carriers can be supplied to the developing devices 4D for each color of cyan, magenta, yellow, and black. Here, the carriers in the carrier holding areas of the hoppers 43C, 43M, 43Y, and 43Bk are augers 44C, 44M, 44Y, which will be described later.
44Bk carrier supply port 441C / 441M / 441
From Y ・ 441Bk Developing device 42C ・ 42M ・ 4 for each color
2Y ・ 42Bk can be supplied.

As shown in FIG. 6, each toner cartridge 41 has a cylindrical shape, and the inside thereof has four toner chambers 45C, 45M, 45Y, and 45 at equal intervals along the rotation direction.
Each of the toner chambers is divided into Bk
Auger 44C communicating with C ・ 43M ・ 43Y ・ 43Bk
・ 44M ・ 44Y ・ 44Bk toner supply port 46C ・ 4
6M, 46C and 46Bk are opened. Here, the low wall plate 4 of each toner chamber 45C, 45M, 45C, 45Bk
7 is a toner supply port 442C / 442M / 44 for each auger
2Y · 442Bk are formed in proximity to each other, and when each toner chamber reaches the vicinity of the uppermost position, the toner on the low wall plate 47 can easily be replenished with toner by the toner supply ports 442C, 442M, 442Y, 442.
It is configured to be supplied to Bk. In addition, each toner chamber 4
A non-illustrated normally-closed port for supplying the toner of each color at a proper time is formed on a part of the outer wall of 5C, 45M, 45Y, 45Bk, and the toner of each color is replenished during maintenance. As shown in FIG. 7, the developing device 42C.4 for each color
2M / 42Y / 42Bk have a developing chamber 48 inside them.
C, 48M, 48Y, and 48Bk, and developing rollers 49C, 49M, 49Y, which are fitted into the windows on the outer peripheral wall side of each developing chamber.
49Bk, these developing chambers and toner chambers 45C and 45
M ・ 45Y ・ 45Bk and each hopper 43C ・ 43M ・
Auger 44C / 44M that communicates with 43Y / 43Bk
It is composed of 44Y and 44Bk.

Each auger 44C, 44M, 44Y, 44B
k is provided with a carrier / toner supply motor 50 supported by the revolver unit 27d, and the screw is rotatably driven by the motor to feed direction, that is, developing units 42C and 42 for each color.
The carrier and toner are fed in an amount corresponding to the rotation amount in the direction toward M, 42Y, 42Bk. Here, the control means (not shown) controls the developing devices 42C, 42M, 42Y for the respective colors.
The respective usage ratios of the 42 Bk developer are calculated, the rotation amount of the carrier / toner supply motor 50 is calculated according to each usage ratio, the same amount of rotation is driven, and each toner and carrier replenishment amount for each color is controlled. Is done. Although the carrier is largely different from the toner replenishment amount, the amount adjustment is performed by adjusting the rotation amount of each auger or each stopper 44C, 44M, 44C.
It can be adjusted by the shape of 44Bk or hopper 43C / 43M / 43C / 43Bk. Furthermore, each developing device 42C
Of the developers in 42M, 42C, and 42Bk, part of the deteriorated developer may be configured to be discharged to the outside by an overflow amount from a discharge port (not shown), and in some cases, may be discharged during maintenance. good.

Here, the auger 44C / 44M / 44Y / 4
4Bk is a carrier supply port 441 on the upstream side in the feeding direction.
C, 441M, 441Y, 441Bk, and the toner supply port 442C, 442M on the downstream side of the carrier supply port.
-442Y and 442Bk, and a discharge port 443 at the downstream end
C, 443M, 443Y and 443Bk are formed respectively. Therefore, each auger 44C / 44M / 44Y
The 44Bk conveys a commonly used carrier from the carrier cartridge 40, and receives the toner from the developing devices 42C, 42M, 42Y, 42Bk for each color at the downstream thereof, and discharge ports 443C, 443M, 443Y, 443Bk.
More developing devices for each color 42C / 42M / 42Y / 42Bk
Then, the developer in which the toner and the carrier are mixed is replenished.
Therefore, each developing device 42C, 42M, 42Y, 42Bk
The color mixture of the toners supplied to is reliably prevented.

When the developing device 4D adopting such a revolver developing system is driven, each developing device roller 49C, 49M, 49Y in the developing device supported by the revolver portion 27d.
49Bk is a developing position P1 facing the photosensitive drum 1d
Then, the electrostatic latent images corresponding to the respective colors are developed. Here, a color-specific electrostatic latent image corresponding to the color-specific image obtained by sequentially separating the original image is formed on the photosensitive drum 1d for each rotation, and the color-specific electrostatic latent image of the revolver unit 27d is formed. The image is developed by the developing roller 49C, 49M, 49Y, 49Bk for each color, which is switched to the developing position P1 for every 1/4 rotation, and the visible images for each color are sequentially superposed on the transfer paper. After the transfer, the transfer image on the transfer paper is fixed, and a full-color image is formed. At this time, the carrier cartridge 40, the toner cartridge 41, and the developing devices 42C supported by the revolver unit 27d.
・ The 42M, 42Y, and 42Bk are integrally rotated to stir the internal carrier, the toner, and the carrier and the developer mixed with the toner. At the same time, the carrier cartridge 40, the toner cartridge 41, and the developing devices 42C
Among the 42M, 42Y, 42Bk, the augers 44C, 44M, 44Y, 44Bk corresponding to the colors located at the respective uppermost positions are rotationally driven by an appropriate amount, and the developing devices 42C, 42M, 42Y, 42
The carrier and toner in Bk are replenished.

As described above, the developing device 4D of FIG. 4 rotates the revolver unit 27d every time an image of a different color is formed, and moves the developing device of the target color to the developing position P1. At the same time, the carrier cartridge 40 and the toner cartridge 41
Since the toner is rotated, the carrier is agitated to ensure that triboelectrification is performed before it is replenished to the developing device side, it is possible to prevent replenishment while it is uncharged, and it is possible to prevent the occurrence of abnormal images due to uncharged carrier supply. . Furthermore, the carrier cartridge 40
A fixed amount of carrier is pumped from each stopper 44 to the inner hoppers 43C, 43M, 43Y, 43Bk,
For this reason, it is possible to accurately replenish the carrier simply by rotating the auger for an arbitrary sufficient period without performing complicated rotation control of the auger. Further, when the auger is also used for toner transport as in the developing device of FIG. 4, the rotation time can be independently controlled for any period without considering the carrier replenishment amount according to the required toner replenishment amount. Therefore, it is very effective in simplifying the configuration.

[0037]

As described above, according to the first aspect of the present invention, a common carrier can be commonly supplied to a plurality of developing devices by a single carrier replenishing means. Therefore, the developing device used here can be easily simplified, downsized, and reduced in cost, and an image forming apparatus that can be easily maintained due to the carrier life can be provided.
According to the second aspect of the present invention, the developing device to which the carrier is to be replenished is moved to the carrier replenishable position before the carrier is replenished. Therefore, the carrier transport path of the developing device used here is simplified or It is possible to provide an image forming apparatus that can be eliminated, facilitates simplification, size reduction, and cost reduction of the apparatus, and is easy to maintain due to carrier life. According to the third aspect of the invention, the carrier replenishment is performed after the carrier replenishing means is moved to the carrier replenishable position of the developing device in which the carrier replenishment is to be performed.
It is not necessary to provide a dedicated carrier transport path for each developing device from the carrier replenishing device used here, which simplifies the device, downsizes the cost, and reduces the cost easily. Can be provided.

According to the invention of claim 4, a plurality of developing devices, one carrier replenishing means, and a revolver type developing device moving means for supporting the developing device are provided, and the carrier replenishing means is attached integrally with the developing device. Since the carrier replenishing means is rotated in conjunction with the movement of the developing device, it is possible to agitate the carrier and charge the carrier in advance before replenishing the carrier, and prevent image deterioration due to replenishing the carrier. it can. According to the invention of claim 5, in the carrier replenishing device of claim 4, since the carrier replenishing means is provided with the pumping means for pumping the carrier by a constant amount according to the rotation, the carrier replenishing amount is quantified by the pumping means. As a result, it is possible to accurately and stably supply a fixed amount of carrier and obtain a stable image. According to a sixth aspect of the present invention, in the carrier replenishing device according to the fourth aspect, the powder replenishing means for mixing and conveying the carrier and the toner is provided, and the replenishment point of the carrier is arranged upstream of the flow path of the powder replenishing means. Since the replenishment point is arranged on the downstream side, it is possible to prevent the toner from being mixed due to the interposition of the carrier replenishing means commonly used in each developing device, and it is possible to provide the image forming apparatus without the image deterioration due to the toner color mixture. Become.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a developing device used in a developing method as an embodiment corresponding to claim 1 of the present invention.

FIG. 2 is a schematic configuration diagram of a developing device used in a developing method as an embodiment corresponding to claim 2 of the present invention.

FIG. 3 is a schematic configuration diagram of a developing device used in a developing method as an embodiment corresponding to claim 3 of the present invention.

FIG. 4 is a schematic configuration diagram of a developing device as an embodiment corresponding to claims 4, 5, and 6 of the present invention.

5 is a sectional view taken along the line AA of the developing device in FIG.

6 is a sectional view of the developing device of FIG. 4 taken along the line BB.

FIG. 7 is a sectional view taken along line CC of the developing device of FIG.

FIG. 8 is a schematic configuration diagram of an image forming apparatus.

9 is an enlarged schematic configuration diagram of a developing device in the image forming apparatus of FIG.

[Explanation of symbols]

 1a photoconductor drum 1b photoconductor drum 1c photoconductor drum 1d photoconductor drum 4 developing device 4A developing device 4B developing device 4C developing device 4D developing device 22 carrier replenishing means 22b carrier replenishing means 25 carrier cartridge 25b carrier cartridge 25c carrier cartridge 26C auger 26M auger 26Y auger 26Bk auger 27 revolver unit 28C developing device 28M developing device 28Y developing device 28Bk developing device 40 carrier cartridge 41 toner cartridge 44C auger 44M auger 44Y auger 44Bk auger P2 carrier supply position

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location G03G 15/01 113 Z (72) Inventor Kai Kai 1-3-6 Nakamagome, Ota-ku, Tokyo -In stock company Ricoh (72) Inventor Nobuto Yokokawa 1-3-6 Nakamagome, Ota-ku, Tokyo-In stock company Ricoh (72) Yoshiko Ishii 1-3-6 Nakamagome, Ota-ku, Tokyo-shares Inside Ricoh Company (72) Inventor Satoshi Muramatsu 1-3-6 Nakamagome, Ota-ku, Tokyo, Stock Company Ricoh Company (72) Masako Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Company Within

Claims (6)

[Claims] 1. A carrier replenishing method for a two-component developing device, comprising: a plurality of developing devices; and one carrier replenishing means, wherein carrier replenishing for each developing device is commonly performed by the carrier replenishing means. . 2. The carrier replenishing method according to claim 1, wherein a plurality of developing devices are configured to be movable to a common carrier replenishable position corresponding to the carrier replenishing means, and the developing device for replenishing the carrier is the carrier. A carrier replenishing method for a two-component developing device, which comprises performing a carrier replenishing operation after moving to a replenishable position. 3. The carrier replenishing method according to claim 1, wherein the carrier replenishing means is configured to be movable to a carrier replenishable position of each developing device, and the carrier replenishing means is a carrier corresponding to the developing device for replenishing the carrier. A carrier replenishing method for a two-component developing device, which comprises performing a carrier replenishing operation after moving to a replenishable position. 4. A plurality of developing devices, one carrier replenishing means, a revolver type developing device moving means for supporting the developing device, wherein the carrier replenishing means is attached integrally with the developing device, and the carrier replenishing means is provided. A carrier replenishing device for a two-component developing device, wherein the carrier replenishing device is configured to rotate in association with the movement of the developing device. 5. The carrier replenishing device according to claim 4, wherein the carrier replenishing means is provided with a pumping means for pumping the carrier in a fixed amount according to the rotation, and the carrier replenishing amount is quantified by the pumping means. A carrier replenishing device for a two-component developing device. 6. The carrier replenishing device according to claim 4, further comprising a powder conveying means for mixing and conveying the carrier and the toner, wherein a carrier replenishing point is arranged upstream of the flow path of the powder conveying means. A carrier replenishing device for a two-component developing device, characterized in that the replenishing point is arranged on the downstream side.