JPH11249402A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce stress of a developer and to stably realize high speed development over a long period. SOLUTION: In this developing device for electrophotographic printing device, a developer storing part 17 is disposed near by a developing vessel 1 provided with developing rolls 4 to 6. At the time of completing the developing work, a developer 2 used in the developing vessel 1 is allowed to shift in the developer storing part 17 by the device of such as a transporting roll 3 through a discharging port 16A. At the time of starting the developing work, a developer located in the developer storing part 17 is allowed to return to the developing vessel 1 through a feed-in member 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an electrophotographic printing apparatus such as an electrophotographic printer.

[0002]

2. Description of the Related Art Conventionally, a multi-stage roll developing machine has been employed in a developing device for a high-speed LBP (laser beam printer). The multi-stage roll developing machine is a multi-stage development roll in which a multi-stage development roll is arranged along a photoreceptor in a development container arranged in the vicinity of the photoreceptor. Are configured to rotate in the same direction as the rotation direction of the photoconductor, and a plurality of developing rolls disposed on the downstream side in the rotation direction of the photoconductor are configured to rotate in a direction opposite to the rotation direction of the photoconductor. A transfer roll is provided at the top of the developing container, and a toner hopper is provided at the top of the developing container, and a mixing / stirring device is provided at the back of the developing roll. A developing machine having such a configuration is disclosed in JP-A-6-202484. Also,
When the developing machine has finished the operation, the developer is in a state of being retained between the bottom of the developing container and the transport roll.

[0003] When the speed of the developing apparatus of this type is increased, the number of rotations of the developing roll increases, the mechanical stress applied to the developer increases, and the developer becomes more fatigued. If the developer that has become heavily fatigued is stored in the bottom of the developer, the developer is further subjected to stress due to the weight of the transport roll, the magnetic attraction of the transport roll, and the like.

[0004]

As described above, if the stress is continuously applied to the developer, the charging performance of the developer is deteriorated, and it takes time to reach a charge amount of a desired polarity. Many stains (fog) of the background portion occur, and the print quality deteriorates.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device which reduces the stress of the developer and realizes stable high-speed development for a long time.

[0006]

In order to solve the above-mentioned problems, the present invention is basically configured as follows.

That is, in a developing device of an electrophotographic printing apparatus, a developer storage section is provided beside a developing container having a developing roll, and when the developing operation is completed, the developer used in the developing container is stored in the developer storing section. The image forming apparatus further includes means for moving, and means for returning the developer in the developer storage section to the developing container at the start of the developing operation.

According to the above construction, when the operation of the developing device is completed, the developer moves from the developing container to the developer storing section, so that the developer can be stored without being subjected to stress due to the weight of the transport roll and magnetic force. At the start of the operation, the developer is returned to the developing container, so that the developer stored in a healthy state can be reused.

[0009]

(Embodiment 1) An embodiment of the present invention will be described with reference to FIGS. 1A is a cross-sectional view illustrating a developing operation state of the developing device according to the present embodiment, FIG. 1B is a cross-sectional view illustrating a state in which the developing operation is completed without the photoconductor 10, and FIG. The state at the start is determined by the photoconductor 10
3 is a side view and a front sectional view of the developer carrying member 18 used in the above embodiment.

As shown in FIG. 1A, reference numeral 10 denotes a photoconductive member having photoconductivity, reference numeral 1 denotes a developing container serving as a main body of a developing device. On one side of the container (the side facing the photoreceptor 10), multi-stage developing rolls 4, 5, and 6 are arranged along the surface of the photoreceptor 10, of which the developing rolls are arranged on the upstream side in the rotation direction of the photoreceptor 10. The configuration is such that the roll 4 rotates in the same direction as the rotation direction of the photoconductor 10, and a plurality of developing rolls 5, 6 arranged on the downstream side in the moving direction of the photoconductor 10 rotate in the opposite direction to the rotation direction of the photoconductor 10. A transport roll 3 that supplies the developer 2 to the upper part of the developing container 1 is disposed at the lowermost part.

A toner hopper 7 for replenishing the toner 8 to the developing unit is provided at the uppermost portion of the developing container 1, and a stirring member 9 for mixing and stirring the replenished toner 8 and the developer 2 is provided below the toner hopper 7.
Here, the developer 2 is composed of a toner and a carrier.

On the side wall of the developing container 1, a developer outlet 16A and a door 16 for opening and closing the outlet 16A are provided below the stirring member 9. The door portion 16 has a function of turning down to the scraper 15 side in the developing container 1 when opening and closing, and guiding the developer 2 to the discharge port 16A side as shown in FIG. 1B.

A developer storage section 17 is provided beside (side) the side opposite to the photoreceptor 10 in the developing container 1. The developer storage section 17 has a substantially V shape, one end of which is connected to the discharge port 16A of the developer container 1, and the other end of which has a developer return port (transport opening) 19A provided at the upper part of the developer container 1. It is connected. The developer return port 19A is provided with a door 19 for opening and closing the return port 19A. Developer return port 19A
Is disposed above the stirring member 9.

A developer carrying member (developer conveying mechanism) for returning the developer 2 to the developing container 1 is provided in the developer storage section 17.
18 are arranged. As shown in FIG. 3, the developer carrying member 18 has a plurality of buckets 21 attached to the outer periphery of a rubber belt 20 in a fixed direction by an adhesive, and pulleys 22 at both ends of the inner periphery of the belt 20. 23 are provided. Since the belt 20 is stretched between the pulleys 22 and 23 with a constant tension, a stable operation can be performed.

A motor 25 is attached to a pulley 22 provided on the upper part.
The developer carrying member 18 is movable by rotating the pulley 22. The belt 20 is preferably made of a non-conductive belt in order to prevent problems due to voltage leakage.

Here, the operation during the development will be described with reference to FIG. During development, the developer 2 is in the developer container 1, and the developer discharge port 16A and the return port 19A are in a closed state.

A part of the developer 2a of the developer 2 is transported on the surface of the roll 3 by the magnetic attraction of the transport roll 3,
It is peeled off by the scraper 14 and is transferred to the developing roll 6 by the guide action of the scraper 14. The developer 2 d remaining on the surface of the transport roll 3 is
And is returned to the lower portion of the developing container 1. The developer 2 a transferred to the developing roll 6 is then transferred to the developing roll 5, transported between the photoreceptor 10 and the developing rolls 5 and 6, and contacts the photoreceptor 10 to develop.

The developer 2a remaining on the surface of the developing roll 6
Is scraped off by the scraper 13 and returned to the lower portion of the developing container 1.

On the other hand, the developer 2b distributed by the developer regulating member 11 is conveyed between the photosensitive member 10 and the developing roll 4, and is brought into contact with the photosensitive member 10 and developed.

The developer 2b remaining on the surface of the developing roll 4
Is scraped off by the scraper 12. The scraped developer 2b falls on the stirring member 9 together with the toner 8 supplied from the toner hopper 7, is mixed and stirred, and is returned to the lower portion of the transport roll 3. The developer 2 distributed by the developer regulating member 11 and not conveyed to the surface of the developing roll 4
c drops by gravity and returns to the lower part of the developing container 1 as it is.

Next, the state when the operation of the developing device 1 is completed will be described with reference to FIG. When receiving the work end signal, the transport roll 3 and the developing rolls 4, 5, and 6 are driven for a predetermined time, and the scraper 14 moves to the vicinity of the developing roll 6. Further, the door portion 16 of the developer outlet 16A falls down into the developing container 1. This turning is performed so as to be in contact with the scraper 15.

The movement of the scraper 14 and the turning operation of the door 16 for discharging the developer are performed simultaneously. Therefore, the developer 2 is conveyed along the surface of the transport roll 3 without being transferred from the transport roll 3 to the developing roll 6, and denoted by reference numeral 2d.
As shown in (1), it is peeled off by the scraper 15, then guided by the door section 16, moved to the developer storage section 17 side through the discharge port 16A, and stored in the developer storage section 17.
Further, the developer 2b transported on the surface of the developing roll 4
After passing through the stirring member 9, the door 1 for opening and closing the developer outlet is also provided.
6 and a developer storage section 17 through a discharge port 16A.
Moved to the side and stored. In this way, the developer 2 can be stored without receiving any stress. The transport roll 3 and the developing rolls 4 to 6 perform the above-described operations, and serve as a unit for moving the developer 2 used in the developing container 1 to the developer storage unit 17 at the end of the developing operation.

Next, the operation when the developing operation is started again will be described with reference to FIG. In response to the work start signal, the door 19 of the developer return port 19A slides upward and opens.
Thereafter, the upper pulley 22 of the developer carrying member 18 rotates counterclockwise by the rotation of the motor 25. The shape of the developer carrying member 18 is such that the bucket 2 is placed on the belt-like member 20.
1 are provided, and when the developer carrying member 18 rotates, the developer 2 stored in the developer storage 17 is provided.
e is pumped up by the bucket 21 on the developer carrying member 18 and returned to the inside of the developing container 1 through the developer return port 19A by using the developer carrying auxiliary member 24.

At this time, the developer 2e is preliminarily stirred by the rotation of the developer carrying member 18. Thereafter, since the developer return port 19 is provided above the stirring member 9, the carried-in developer 2 e is further stirred and mixed by the stirring member 9 and then enters the lower portion of the developing container 1.

Since the developer 2e is mixed and stirred by the developer carrying member 18 and the stirring member 9 before starting the operation, a stable image quality can be obtained. By repeating the above operation for a certain period of time, all the developer 2e in the storage 17 is returned to the inside of the developing device 1. Thereafter, the developer carrying member 18 stops,
Thereafter, the developer carrying-in port 19 slides downward to close the developer returning port 19A, and the developing device 1 enters a work start state. By performing the above-described operation, the developer carrying member 18 serves as a unit for returning the developer in the developer storage unit 17 to the developing container 1 at the start of the developing operation.

(Embodiment 2) A second embodiment of the present invention will be described with reference to FIG.

FIGS. 4 (a) and 4 (b) are cross-sectional views showing an operation state in which the developer is automatically replaced in the developing device according to the second embodiment. Omitted.

In this embodiment, the basic structure is the same as that of the first embodiment, except that a discharge container 27 for discharging the developer 2 is provided below the developer storage section 17. The developer 2 is placed in the discharge container 27.
Is provided at one end of the developer storage section 17, and a developer discharge port 16A of the developer container 1 is obliquely inserted into the receiving port 26A from above. The positional relationship is set so that you can face it.

A part of the developer storage part 17 is provided with a new developer supply part 28 so as to be located near the upper part of the pulley 23 below the developer carrying member 18.

Reference numeral 31 denotes a new developer to be supplied into the developer storage unit 17. A developer supply port 29 is provided at an upper part of the developer supply part 28, and a developer supply port 30A and a supply port 30 are provided at a lower part.
A door 30 that opens and closes A is provided.

Although not shown, during development, the door 1
6 and the door 19 are both closed, and the developing operation at this time is performed in the same manner as in FIG. When the developing operation is completed, the door 19 is closed and the door 16 is open, and the same operation as in FIG. 1B is performed. When the development is restarted, the door 16 is closed and the door 19 is opened, and the same operation as in FIG. 2 is performed. Further, when the developer is worn out and needs to be replaced, the operations shown in FIGS. 4A and 4B are performed, and this operation will be described below.

As shown in FIG. 4A, when the developer is replaced, the door 16 of the developer outlet 16A is connected to the developing container 1A.
The door 16 falls into the open state, and the tip of the door 16 contacts the scraper 15 so that the door 16 becomes a developer conveying path. In this state, the conveying rolls 3 and the developing rolls 4, 5, and 6 are driven for a predetermined time. The developer moves from the developing container 1 to the developer storage 17 side.

The developer 2e discharged from the developer outlet 16A
Enters the discharge container 27 through the developer receiving port 26A, and is then discarded.

After the old developer is discharged as described above, as shown in FIG. 4B, the door 16 returns to the original position, the developer discharge port 16 is closed, and the developer supply container The developer supply port 30A of the developer supply section 28 opens, and a new developer 31 enters the developer storage section 17. In this state, since the developer carrying member 18 is operating and the door 19 is also open, a new developer 31 is carried into the developing container 1. By performing the above operation, the replacement with the new developer is completed. This operation can be automatically performed by a signal from a page counter, a sensor for sensing the driving time of the developing container, or the like.

If a problem occurs during the use of the developer 2 and it becomes necessary to replace the developer 2 with a new developer, the above operation can be performed manually regardless of the signal from the sensor. I can do it. New developer 31 can be replenished into the developer replenishing chamber 28 at any time through a developer charging port 29 provided in the upper part of the developer replenishing container 28.

The developer outlet 16 can be provided at the lower part of the developing container 1.

[0037]

According to the present invention, since the stress on the developer due to the high speed can be reduced, stable and good image quality can be obtained.

[Brief description of the drawings]

FIG. 1A is a schematic sectional view showing a working state of a developing device of an electrophotographic printing apparatus according to one embodiment of the present invention,
(B) is a schematic sectional view showing the end of the operation of the developing device of the electrophotographic printing apparatus according to the present invention.

FIG. 2 is a schematic cross-sectional view showing the start of the operation of the developing device of the electrophotographic printing apparatus according to the embodiment.

FIG. 3 is an enlarged view of a developer carrying member.

FIGS. 4A and 4B are schematic cross-sectional views illustrating a developer replacement state of a developing device according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Development container, 2 2a, 2b, 2c, 2d, 2e ... Developer, 3 ... Conveying member, 4, 5, 6 ... Development roll, 7 ... Toner hopper, 8 ... Toner, 9 ... Stirring member, 10 ... Photosensitivity Body, 11: developer regulating member, 12: scraper, 13
... Scraper, 14 ... Scraper, 15 ... Scraper,
16A: developer discharge port, 17: developer storage section, 18: developer carrying member, 19A: developer carrying port, 20: belt,
21: bucket, 22, 23: pulley, 24: developer carrying-in auxiliary member, 25: motor, 26: developer discharging member, 2
7: discharge container, 28: developer supply chamber, 29: developer supply port, 30: developer supply port, 31: new developer.

Claims (3)

[Claims] In a developing device of an electrophotographic printing device,
Means for providing a developer storage section beside a developing container having a developing roll, means for moving the developer used in the developing container to the developer storing section at the end of the developing operation, and storing the developer at the start of the developing operation Means for returning the developer in the section to the developing container. 2. A stirring means for preliminarily mixing and stirring the developer in the developer storage section.
The developing device as described in the above. 3. A developing device for supplying a developer to a photoconductive photoreceptor and performing magnetic brush development, wherein a developer storage unit is provided beside a developing container having a developing roll. Means for moving the developer used in the container to the developer storage section, means for returning the developer in the developer storage section to the developer container at the start of the developing operation, and A developing device comprising: means for discharging the developer from the container; and means for replenishing the developing container or the developer storage with new developer after the developer is discharged.