JP3078988B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, such as an electrostatographic copying apparatus, which recycles a developer collected by a cleaning means after image formation to a developing process by a transport device. The present invention relates to an image forming apparatus that replenishes a developing device after mixing and stirring a developer and a fresh developer in a hopper.

[0002]

2. Description of the Related Art As is well known, an electrostatic latent image is formed on an electrostatic latent image carrier, and the electrostatic latent image is developed with a developer. Such an image forming apparatus is widely put to practical use. In a series of processes of such an image forming apparatus, an image formed on the electrostatic latent image carrier is transferred to a transfer material, and then fixed on the transfer material via a fixing device. At this time, the residual developer that has not been transferred onto the transfer material is further removed from the electrostatic latent image carrier by a cleaning device disposed downstream of the electrostatic latent image carrier in the rotation direction.

Conventionally, the developer collected by the cleaning device has been discarded as waste developer because it contains foreign substances such as paper dust. However, in recent years, while effective use of resources has been called for in recent years, in order to effectively reuse the collected developer, the collected developer from which contaminants have been removed through a regeneration device such as a filter is a developer that supplies fresh developer. The toner is collected in a hopper and is again subjected to development together with a fresh developer by a developing device.

[0004]

However, in the above-mentioned conventional example, in the case of a configuration in which the recovered developer is directly returned to the fresh developer in the developer hopper by the transport device, the discharge port of the transport device is blocked by the fresh developer. As a result, the collected developer is not efficiently discharged. Also, when dropping the collected developer from above the fresh developer,
The recovered developer is deposited in a layer on the fresh developer. Therefore, when it is supplied to the developing device, there is a problem that the developed image is deteriorated because the recovered developer is partially large.

In order to solve this problem, a proposal has been made in which a fresh developer and a recovered developer are mixed in advance in a stirring chamber and then replenished to a developing device, but the device becomes complicated. However, there is a problem that the cost is increased.

Accordingly, a first object of the present invention is to provide an image forming apparatus capable of replenishing a developing device after sufficiently mixing and stirring a collected developer and a fresh developer with a simple configuration. .

A second object of the present invention is to provide an image forming apparatus capable of always keeping the amount of the collected developer taken in the fresh developer constant even when a large amount of the collected developer is generated. That is.

[0008]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
A cleaning unit that collects residual developer after image formation on the image carrier; and a hopper unit that stores developer to be supplied to the developing device, wherein the developer collected by the cleaning unit is transported by the transport device. Returning to the hopper section, in the image forming apparatus to be subjected to the development process again, the hopper section is provided with a stirring means for the developer, and a discharge section of the conveyance device for conveying the collected developer is disposed near the stirring means, The periphery of the discharge portion is covered with a partition member having only a lower portion opened in the direction of gravity, and the developer collected in the space covered by the partition member is discharged into the hopper portion, and the developer is discharged into the hopper portion. An image forming apparatus characterized in that a mixed developer and a fresh developer are mixed and stirred, and then the mixed developer is supplied to the developing device.

It is preferable that the stirring means is configured to be driven in a direction in which the collected developer discharged into the hopper is taken into the fresh developer.

It is preferable that the partition member discharge port is inclined in a direction to close the internal space.

It is preferable that a collected developer replenishing means is disposed at the partition member discharge port, and the driving of the collected developer replenishing means is synchronized with the driving of the stirring means.

The recovered developer replenishing means is a roller body, which has a predetermined gap between the partition wall member and the inner wall of the hopper, and a protrusion for scraping off the recovered developer coated on the roller body. Is preferably formed on the inner wall or the partition member of the hopper.

[0013] It is preferable that the position of the discharge portion of the conveying device is located at a position facing the developer replenishing means for replenishing the developing device with the mixed developer around the stirring means.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Embodiment 1 A first embodiment of the image forming apparatus according to the present invention will be described with reference to FIG. 1 showing the overall configuration of the image forming apparatus and FIG. 2 showing the configuration of a hopper for supplying developer to the developing device. .

In FIG. 1, the image forming apparatus has an image carrier 1 for forming a latent image substantially at the center, and a developing device 2 for developing the latent image on the image carrier 1 and an image carrier 1 around the image carrier. A transfer charger 4 for transferring the upper toner image onto the transfer material, a transfer separation charger 4a for separating the transfer material from the image carrier 1, and a cleaner 5 for collecting the developer remaining on the image carrier 1. A collected developer transporting device 6 for transporting the developer collected by the cleaner 5 to a hopper 3 described below, a primary charger 7 for charging the image carrier 1, an optical system 8 for reading a document image, and an image carrier 1. An exposure unit 8a for writing a latent image and a document processing unit 9 for guiding a document to a reading unit are provided.

The image forming apparatus includes a transfer material feeding unit 10 for feeding a transfer material to an image forming unit, a transfer table 11 for transferring a transfer material on which a toner image has been transferred to a fixing unit 12, and a transfer device for transferring a toner image. A fixing unit 12 for fixing the transfer material, a transfer material discharging unit 13 for discharging the transfer material after the image formation is completed, and an intermediate tray 1 for forming the transfer material having the image formed on the first surface on the second surface.
5, a re-feeding transfer material guiding section 14, an intermediate tray 15
And a transfer material re-feeding section 16 for feeding the transfer material stored in the image forming section to the image forming section again.

Next, the developing device 2 and the hopper 3 attached to the developing device 2 will be described with reference to FIG. The developing device 2 is disposed so as to face the image carrier 1, and has a blade 20.
A developing sleeve 201 for developing the developer coated on the image bearing member 1 on the image carrier 1, and is rotated in the direction of the arrow by a driving unit (not shown) to
Agitating means 203 and 204 for feeding the developer to the side 01, and a remaining amount detecting sensor 205 for detecting the remaining amount of the developer in the developing device
It has.

Next, the hopper 3 for feeding the replenishment developer to the developing device 2 will be described. The hopper unit 3 includes a replenishing magnet roller 301 for replenishing the developer in the hopper unit to the developing device 2 and a replenishing magnet roller 3 for supplying the developer.
A stirring bar 302 is provided near the stirring bar 302 and is provided near the stirring bar 302. The partition wall member 303 is opened only at the bottom in the direction of gravity and closed at the top. The stirring rod 302 is driven to rotate by a drive system (not shown) in the direction of the arrow so as to easily pull the collected developer T1 into the fresh developer T2. In the space formed by the partition member 303, the discharge portion 6a of the collected developer transport device 6 is disposed, and the collected developer is discharged into the space.

Next, the operation of the image forming apparatus configured as described above will be described. When a copy operation button (not shown) is pressed, the document in the document processing device 9 is guided to a reading unit, and the document image is read by the optical system 8.
The image carrier 1 is charged to a predetermined potential by the primary charger 7, and then a latent image corresponding to the document image is written by the exposure unit 8a. Next, the latent image on the image carrier 1 is developed by the developing device 2. At this time, the remaining amount detection sensor 205
When the developer is detected to be insufficient in the developing device 2, the developer is appropriately replenished to the developing device 2 from the hopper 3.

When the transfer material is fed from the transfer material feeding unit 10 to the image forming unit, the image on the image carrier 1 is transferred to the transfer charger 4.
The image is transferred onto the transfer material by the transfer table 11 and sent to the fixing unit 12 by the transfer stand 11, and the image on the transfer material is fixed. In the case of one-sided copy, the copy is discharged to the transfer material discharge section 13 as it is,
In the case of the double-sided mode or the multiple mode, the sheet is not discharged as it is, and the intermediate tray 15 is
After a predetermined number of sheets are stacked and stored on the upper side, the transfer materials are separated and fed one by one by the transfer material re-feeding unit 16 and fed again to the image forming unit. Then, when the next document is placed on the platen by the document processing device 9, a second image is formed, the image is fixed by the fixing unit 12, and then discharged to the transfer material discharge unit 13.

The residual developer remaining on the image carrier 1 that has not been transferred onto the transfer material by the transfer charger 4 is scraped off by the cleaner 5 and collected by cleaning. The developer cleaned here is regenerated by a developer regenerating device (a device that separates the developer and paper dust and other foreign matters from the residual developer and extracts only the developer) (not shown).
The collected developer is transported to the hopper 3 by the developer transport device 6 and is discharged.

Next, the operation of the hopper 3 will be described. The recovered developer transported by the recovered developer transport device 6 is discharged into the space formed by the partition wall member 303. The partition member 303 is connected to the front and rear side walls of the hopper container 3a, and further, a lower portion in the direction of gravity is opened to form a discharge port 303a (the discharge port portion is inclined in a direction to further close the internal space). Since the upper portion is closed, the fresh developer filling the periphery of the partition wall member 303 is hard to enter the inside of the partition wall even if it has good fluidity. Therefore, when the collected developer T1 is discharged into the space formed by the partition member 303, the fresh developer T2 blocks the discharge port 6a of the collected developer transport device 6 and prevents the collected developer T1 from being discharged. I will not do it.

The stirring means 302 disposed near the discharge port 303a of the partition wall member 303 discharges the collected developer to the discharge port 303.
03a, the recovered developer T1 that has been discharged is rotated downward from the vicinity of the fresh developer T2.
Is easily taken into the fresh developer T2
And the recovered developer T1 are sufficiently mixed and stirred. Further, the mixed and stirred developer is conveyed to the supply magnet roller 301 by the action of the stirring rod 302, and then supplied to the developing device 2. Since the mixed developer supplied to the developing device 2 is sufficiently mixed and stirred, there is no possibility that the recovered developer is partially large and the developed image is deteriorated.

Further, in order to ensure mixing and stirring properties of the fresh developer and the collected developer, the discharge position of the collected developer conveying device is preferably arranged at a position opposed to the replenishing magnet roller around the stirring means. This is to secure an opportunity to be mixed and stirred with the fresh developer before the collected developer is supplied to the developing device.

As described above, in this embodiment, the recovered developer and the fresh developer can be sufficiently mixed and stirred by a simple structure and then replenished to the developing device. No inconsistency is caused in the developed image due to the occurrence of unevenness. Therefore, the collected developer can be reused without any trouble.

Embodiment 2 In the first embodiment, the recovered developer supplied from the recovered developer transport device was directly taken into the fresh developer, but the recovered developer was generated in a large amount when the copy density was high. And
If the developer is conveyed and discharged as it is to the hopper 3, the amount of the recovered developer may be larger than that of the fresh developer. This embodiment is characterized in that means for solving this problem are provided.

As shown in FIG. 3, the hopper section 3 of the present embodiment is characterized in that a collected developer supply roller 304 is disposed at the discharge port 303a of the partition wall member 303, and the rest is substantially the same as the first embodiment. It has the same configuration.

The developer recovered in the same manner as in the first embodiment is
The collected developer is transported to the space inside the partition member 303 by the developer transport device 6. However, the outlet 30 of the partition member 303
Since the collected developer supply roller 304 is provided in 3a, the collected developer T1 is temporarily stored on the collected developer supply roller 304 without being directly taken into the developer. Then, the collected developer supply roller 304 is driven by a drive system (not shown) in synchronization with the stirring means 302. The collected developer supply roller 304 is coated with the collected developer having a thickness corresponding to the gap with the partition member 303, and is forcibly scraped off by the protrusion 305 formed on the inner wall of the hopper container 3a. If this coating amount is set to an appropriate amount, even if a large amount of the collected developer is generated, the amount of the collected developer taken into the fresh developer can always be kept constant. The amount of the collected developer does not increase and does not deteriorate the developed image.

Embodiment 3 Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS. The present embodiment is characterized in that a configuration is provided in which the stirring means provided in the hopper section is driven when the transfer device for transferring the collected developer is driven. Further, the present embodiment has substantially the same configuration as the first embodiment, and therefore, only the characteristic portions will be described.

As shown in FIG. 4, a drive clutch 306 is connected to a rotation shaft of the supply magnet roller 301 via a second drive pulley 309, and a rotation shaft of the stirring rod 302 is connected to a first drive pulley 302b. The intermediate gear 302a is connected. A drive gear 307a is connected to the stirring rod drive motor 307, and an intermediate gear 302a is meshed with the drive gear 307a. Further, the first driving pulley 30
A drive belt 308 is stretched between 2b and the second drive pulley 309.

As shown in the block diagram of FIG. 5, a motor control unit 602 and a toner remaining amount detection control unit 603 are connected to the main body control unit 600, and the motor control unit 602 controls a motor 307 for driving a stirring rod and a collected developer. The drive of the main body drive motor 604 that drives the transport device 6 is controlled. The toner remaining amount detection control unit 603 includes a clutch control unit 6
05 is connected, whereby the engagement and disengagement of the supply roller drive clutch 306 is controlled.

In the above-described configuration, since the drive of the collected developer transporting device 6 is input from the main body driving source, the collected developer collected by the cleaner 5 is supplied to the hopper section while the apparatus main body is driven. Conveyed to 3.

The stirring rod 302 disposed near the discharge port of the partition member 303 is driven to turn on and off the collected developer downward from near the discharge port 303a in synchronization with the drive of the apparatus main body as shown in FIG. Therefore, the discharged recovered developer T1 is easily taken into the fresh developer T2 immediately by the action of the stirring bar 302. Therefore, the ratio of the collected developer T1 does not increase due to the partial volume of the collected developer T1, and the fresh developer T2 and the collected developer T1 are sufficiently mixed and stirred. Further, the mixed and stirred developer is conveyed to the supply magnet roller 301 by the action of the stirring rod 302.

When the remaining amount detecting sensor 205 detects that the developer is insufficient in the developing device 2, the driving force is transmitted to the supply magnet roller 301 by the operation of the driving clutch 306, and the developer is transferred to the developing device 2. Is supplied. Since the mixed developer supplied to the developing device 2 is sufficiently mixed and stirred, there is no possibility that the recovered developer is partially large and the developed image is deteriorated.

In this embodiment, the stirring rod and the magnet roller are driven by a dedicated drive motor.
The present invention is not limited to the present embodiment, and similar effects can be expected even if the drive is configured to be input from the main body drive source, or each is driven by a dedicated motor. That is, the gist of the present invention is to drive the agitating means at least when the collected developer transport device is driven, and to immediately take the collected developer discharged into the hopper into the fresh developer.

As described above, according to the present invention, the recovered developer and the fresh developer can be mixed and agitated by a simple structure and then replenished to the developing device. Does not occur and no inconvenience occurs in the developed image. Therefore, the collected developer can be reused without any trouble, and the cost can be reduced.

Embodiment 4 Next, a fourth embodiment of the image forming apparatus according to the present invention will be described with reference to FIG.

In the above embodiment, the case where the number of stirring rods is one has been described, but the same effect can be expected in the case of a plurality of stirring rods.

In this embodiment, as shown in FIG.
This is the same as the above-described embodiment except that the second stirring rod 310 is arranged on the downstream side of the conveyance of the stirring rod 302. The description of the drive system is omitted.

The first stirring rod 302 is turned on and off in synchronization with the driving of the main body, as in the third embodiment. The second stirring rod 310 has the same drive source as the supply magnet roller 301, and is turned on and off in the direction of the arrow shown in the drawing by detection of the remaining amount detection sensor 205 of the developing device 2.

As in the third embodiment, the collected developer transport device 6
The collected developer T1 discharged into the partition member 303 of the hopper 3 by the first stirring rod 302
Since it is rotationally driven downward in the direction of the arrow shown in FIG. 7 from below the vicinity of a, it is immediately taken into the fresh developer T2. Here, the recovered developer mixed and stirred with the fresh developer is transported to the second stirring rod 310 on the further downstream side.

Here, when the remaining amount detection sensor 205 detects that the developer is insufficient in the developing device 2, the supply magnet roller 301 and the second stirring rod 310 are driven to rotate, and the developer is transferred to the developing device 2. At the same time as replenishment, the mixed developer is conveyed to the replenishment magnet roller 301 side while further mixing and stirring the fresh developer. When the rotation driving operation is repeated, the mixed developer is supplied to the developing device 2. Since the mixed developer supplied to the developing device 2 is sufficiently mixed and stirred, there is no possibility that the recovered developer is partially large and the developed image is deteriorated.

In this embodiment, the second stirring rod 310 is driven in synchronization with the supply magnet roller 301.
The same effect can be expected even when the driving is performed in synchronization with the first stirring rod 302. Thus, the gist of the present invention is that at least when the recovered developer transport device is being driven, the stirring means disposed near the recovered developer transport device is driven,
In other words, the collected developer discharged to the hopper member is immediately taken into the fresh developer.

As described above, according to the present invention, the recovered developer and the fresh developer can be sufficiently mixed and stirred by a simple structure and then replenished to the developing device. No inconsistency arises in the developed image due to the unevenness of the image. Therefore, the collected developer can be reused without any trouble, and the cost can be reduced.

[0046]

As is apparent from the above description, the present invention provides a cleaning means for collecting the residual developer after image formation on the image carrier, a hopper for accommodating the developer to be supplied to the developing device, and In the image forming apparatus, the developer recovered by the cleaning unit is returned to the hopper unit by a transport device, and is again subjected to the developing process. The hopper unit includes a developer stirring unit, and is provided near the stirring unit. A discharge unit of a transport device for transporting the collected developer is arranged, the periphery of the discharge unit is covered with a partition member having only a lower part opened in the direction of gravity, and the developer collected in the space covered by the partition member is hopper. The mixed developer and fresh developer discharged into the hopper are mixed and stirred, and then the mixed developer is supplied to the developing device. Depending on the configuration, the recovered developer and fresh developer can be sufficiently mixed and agitated and then replenished to the developing device, so that partial unevenness due to the charging characteristics of the developer can be prevented, and a good developed image can be obtained. Obtainable. Therefore, the recovered developer can be reused without any trouble, which is very preferable in terms of economic efficiency and resource saving.

Further, the recovered developer replenishing means is a roller, which has a predetermined gap between the roller and the partition member, and which is provided with a projection for scraping off the recovered developer coated on the roller. By forming it on the inner wall, even if a large amount of collected developer is generated, the amount of collected developer taken into the fresh developer can always be kept constant. Deterioration of an image can be prevented, and a good image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a hopper section of the image forming apparatus of FIG. 1 for supplying a developer to a developing device.

FIG. 3 shows a second example of the hopper of the image forming apparatus according to the present invention.
It is a block diagram which shows an Example.

FIG. 4 is a configuration diagram of a hopper drive system, showing a third embodiment of the image forming apparatus according to the present invention.

FIG. 5 is a block diagram showing the drive system of FIG.

FIG. 6 is a timing chart showing drive timings of the drive system of FIG.

FIG. 7 is a configuration diagram of a hopper, particularly showing a fourth embodiment of the image forming apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 2 Developing device 3 Hopper part 6 Collection | recovery developer conveyance apparatus 7 Cleaning means 11 Transport means 301 Supply magnet roller (developer supply means) 302 Stirring means 303 Partition member 303a Discharge port 304 Collection developer supply means 305 Projection part T1 Recovered developer T2 Fresh developer

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI G03G 21/10 G03G 15/08 507E 21/00 326 (56) References JP-A-62-111680 (JP, A) JP-A Heisei 2-82274 (JP, A) JP-A-4-107585 (JP, A) JP-A-62-296158 (JP, A) JP-A-59-155864 (JP, A) JP-A-5-341645 (JP, A) A) JP-A-58-102271 (JP, A) JP-A-62-154463 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/08-15/095 G03G 21 / 10-21/12

Claims (6)

(57) [Claims] An image forming apparatus comprising: a cleaning unit that collects a residual developer after image formation on an image carrier; and a hopper unit that stores a developer to be supplied to a developing device, wherein the developer is collected by the cleaning unit. Returning to the hopper portion by a transport device and again performing the developing process, wherein the hopper portion has a developer stirring means, and a discharge section of the transport device which transports the collected developer to the vicinity of the stirring means. Is disposed, the periphery of the discharge portion is covered with a partition member having only a lower portion opened in the direction of gravity, and the developer collected in the space covered by the partition member is discharged into the hopper portion, An image forming apparatus comprising: mixing and agitating a collected developer and a fresh developer discharged into a hopper; and replenishing the mixed developer to the developing device. 2. An image forming apparatus according to claim 1, wherein said stirring means is driven in a direction in which the collected developer discharged into said hopper is taken into fresh developer. 3. The image forming apparatus according to claim 1, wherein an outlet of the partition member is inclined in a direction to close an internal space. 4. A recovery developer supply means is disposed at an outlet of said partition member, and the drive of said recovery developer supply means is synchronized with the drive of said stirring means.
The image forming apparatus according to any one of the above items. 5. The recovered developer replenishing means is a roller, which has a predetermined gap between the partition member and the inner wall of the hopper, and scrapes the recovered developer coated on the roller. 5. A projection formed on an inner wall of the hopper or a partition member.
Image forming apparatus. 6. The apparatus according to claim 6, wherein a position of a discharge portion of the transporting device for the collected developer is disposed at a position facing the developer replenishing device for replenishing the developing device with the mixed developer around the stirring device. The image forming apparatus according to claim 1.