JPH01314266A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To prevent toner blocking arising on the inner wall, etc., of a toner hopper by providing an agitating means which orients toward one side of the bottom of the toner hopper from the other side and which travels along an almost entire bottom of the toner hopper and a control means changing the moving direction while the agitating member travels. CONSTITUTION:The title device is provided with the agitating member 20 which divides the bottom of the toner hopper 9 with the aid of a recessed part 9b possessing a toner discharge port 15, houses a toner discharge roller 14 blocking the toner discharge port 15 in the recessed part 9b, pass above the recessed pat 9b toward the one side divided by the recessed part 9b and moves to the other of the bottom, and the control means changing the moving direction while the agitating member travels. Consequently, a toner 8, adhering to the surface of the toner discharge roller 14 and never falling from the toner discharge port 15, can again be returned to the recessed part 9b by the agitating member 20 even if it returns to the toner hopper 9. Thus, the toner 8 never resides in the toner hopper 9 due to a blocking phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to electrophotography in which an electrostatic latent image formed on a photoreceptor is developed using toner particles, the toner is transferred to paper, and the image is fixed by heat, pressure, etc. It is related to the device.

2. Description of the Related Art Conventionally, most electrophotographic devices have been devices that use dry toner, and have been put into practical use as copying machines, laser printers, and the like. This electrophotographic apparatus is a device that applies electrophotographic process technology, and in the electrophotographic process, a developing process is to develop an electrostatic latent image formed on a photoreceptor using toner particles. A device that constitutes a developing process. For example, a developing device that uses a two-component developing method that uses a mixture of toner and carrier as a developer generally uses a developing vat filled with developer and a toner hopper that stores replenishment toner. It has become. The toner in the toner hopper falls into the developing vat by the rotation of the toner supply roll, and is controlled so that the mixing ratio of toner and carrier in the developing vat is always kept constant. The toner filled in the toner hopper decreases as the toner is used, and some of the toner may adhere to the inner wall of the toner hopper, causing toner blocking (solidification), or be deposited in stagnation areas. When toner remains in the toner hopper, the capacity of the toner hopper is substantially reduced. Therefore, various attempts have been made to reduce toner blocking and toner remaining in the stagnation.

Hereinafter, a conventional developing device in an electrophotographic apparatus will be described with reference to the drawings.

FIG. 5 is a side sectional view of a conventional developing device, and FIG. 6 is a perspective view of a main part of a toner hopper of the conventional developing device.

In FIGS. 5 and 6, reference numeral 1 denotes a photoreceptor which is made of a cylinder made of aluminum or the like, and has a photosensitive layer such as selenium (Se) or organic photoconductor (OPC) applied in the form of a thin film on its outer peripheral surface. Reference numeral 2 denotes a charger, which is composed of a charging wire 3 made of tungsten wire or the like, a shield plate 4 made of a metal plate, and a grid plate 5. By applying a high voltage to the charging wire 3, the charging wire 3 causes corona discharge, and the photoreceptor 1 is uniformly charged via the grid plate 4. 6 is an exposure light beam emitted from an optical unit (not shown);
In the case of a copying machine, this is document light, and in the case of a laser printer, it is image data light. In the case of a laser printer, this exposure beam 6 is controlled by signals from a host computer (not shown), and the desired image is formed as an electrostatic latent image on the photoreceptor l. 7 is a developing device, which includes a toner hopper 9 that stores toner 8, and a developing device that stores toner 8 and carrier 10, which is magnetic particles such as iron powder, and after mixing and stirring, transports the toner to developing sleeve 11 to form a magnetic brush. It consists of a bat 12. 13 is a toner hopper lid. 14 is rotatably supported at both ends within the toner hopper 9.
This is a toner discharge roller that supplies a certain amount of toner 8 into the developing vat 12 and closes the toner discharge port 15. Reference numerals 16a and 16b are loop-shaped motion transmitting members such as belts, chains, or lobes. Motion transmission member 16a
, 16b are sprockets 18a, 18 fixed to a rotating shaft 17 whose both ends are supported in parallel with the toner discharge roller 14.
b and the fixed shaft 19. 20 is arranged substantially parallel to the rotating shaft 17, and has both ends connected to the motion transmitting member 16.
This is a shaft-shaped stirring member attached to parts a and 16b. Sprockets 18a, 18b and toner discharge roller 1
4 is rotated by driving a sprocket gear 26 and a toner discharge roller gear 27, respectively, via idler gears 23, 24, and 25 using power from a motor 22 such as a stepping motor disposed on a chassis 21 of the machine body. Furthermore, the toner discharge roller 14 is arranged close to the toner hopper inner wall 9a. Motion transmission members 15a, 16b1 rotating shaft 17, sprockets 18a, 1
8b, the rotating shaft 19 is attached to move the stirring member 20 along the inner wall of the toner hopper 9. 2
8 is a developer mixer, which is disposed within the development vat 12.

The developer mixer 28 stirs and mixes the toner 8 supplied from the toner hopper 9 through the toner discharge port 15 and the carrier 10, charges the toner, and conveys the toner to the developing sleeve 11.

The transported toner 8 and carrier 10 are transferred to the developing sleeve 11
A magnetic brush is formed by the magnetic force of a magnet roller 29 fixed therein, and its height is limited by a doctor blade 30. As the developing sleeve 11 rotates, the magnetic brush comes into contact with the photoreceptor 1 and causes the toner 8 to adhere to the portion of the photoreceptor 1 where the electrostatic latent image is formed, thereby forming a powder image. 31 is a toner concentration sensor for detecting the mixing ratio of toner 8 and carrier 10;
is attached to. 32 is a developing section where development is performed.

Next, the operation of the above configuration will be explained. First, a corona discharge is caused by a charging wire 3 in a charger 2 connected to a high-voltage power source to uniformly charge the surface of the photoreceptor 1 to about -600V to -700V. Next, the photoreceptor 1 is rotated in the direction of arrow A and an exposure beam 6 such as a laser beam is irradiated onto the uniformly charged surface of the photoreceptor 1, and the irradiated portion of the photoreceptor 1 loses its charge. An electrostatic latent image is formed. On the other hand, the carrier 10 and toner 8 in the developing vat 12 are transferred to the developer mixer 28.
is sufficiently frictionally charged and attracted to the magnet roller 29, and is conveyed to the developing section 32 by the rotation of the developing sleeve 11. In this developing section 32, the carrier 10 and the toner 8 form a magnetic brush and come into contact with the photoreceptor l. At this time, if a potential difference is applied between the developing sleeve 11 and the photoreceptor 1,
The toner 8 adheres to the electrostatic latent image portion on the photoreceptor 1 to form a visible image, and development is completed. Here carrier 10 and toner 8
The mixing ratio with toner is constantly sensed by the toner concentration sensor 31. When the toner 8 adheres to the photoreceptor 1 in the developing section 32 and is consumed, the toner concentration sensor 31 detects the toner in the developing vat 12.
It is detected that the mixing ratio of carrier 10 and toner 8 in the motor 2 is lower than a preset value, and the detection signal is sent to a host computer (not shown), and as shown in FIG.
2 and rotates the toner discharge roller 14 through various gears 23, 24, 25, 26, 27 to open the toner discharge port 1.
5, the toner 8 in the toner hopper 9 is replenished onto the developer mixer 28 in the developing vat 12, and the set mixing ratio is restored to maintain a constant mixing ratio.

Problems to be Solved by the Invention In the conventional developing device configured as described above, the toner 8 in the toner hopper 9 is initially in the state shown by line B in FIG. 5 when it is filled. As the toner discharge roller 14 rotates, the toner 8 in the toner hopper 9 falls into the developing vat and gradually decreases. The toner 8 filled between the toner discharge roller 14 and the toner hopper inner wall 9b is stirred by the stirring member 20 as the motion transmission members 16a and 16b rotate in the direction of arrow C, and the toner 8 is transferred to the toner discharge roller 14 side. 8 is pushed aside. This prevents the toner 8 from stagnation, accumulation, and blocking. However, even if the toner 8 on the stirring member 20 side runs out, the toner 8 on the toner discharge roller 14 remains as shown in D (
There was a phenomenon where blocking occurred and the data remained unconsumed. This phenomenon occurred particularly in high temperature and high humidity conditions such as an air temperature of 40° C. and a relative humidity of 80%.

Means for Solving the Problems However, the present invention eliminates the above drawbacks by providing a stirring member that runs from one side of the bottom surface of the toner hopper to the other and along almost the entire bottom surface of the toner hopper, Furthermore, a control means is provided for changing the moving direction of the stirring member during operation.

Effect: With the above means, toner falls from the toner outlet as the toner discharging roller rotates, and some of the toner adheres to the surface of the toner discharging roller and returns to the toner hopper.
Alternatively, the toner on the agitation member passes over the toner ejection roller and causes blocking in the toner hopper, but when the moving direction of the toner ejection roller changes, the blocked toner is transported to the toner ejection roller again by the agitation member. It will be done. This can prevent toner blocking that occurs on the inner wall of the toner hopper.

Example An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view showing an embodiment of the electrophotographic apparatus of the present invention, and FIG. 2 is an exploded perspective view of a portion of the toner hopper of the electrophotographic apparatus of the present invention.

In FIGS. 1 and 2, 1 is a photoreceptor, 2 is a charger, and is composed of a charging wire 3, a shield plate 4, and a grid plate 5. 6 is an exposure light beam emitted from an optical unit (not shown). A developing device 7 includes a toner hopper 9 for storing toner 8 and a developing vat 12.

A carrier 10 is mixed with the toner 8 and stirred. The toner 8 and carrier 10 are then conveyed to a developing sleeve 11 to form a magnetic brush. 13 is a toner hopper lid. A toner discharging roller 14 is rotatably supported at both ends within the toner hopper 9, supplies the toner 8 within the toner hopper 9 into the developing vat 12, and closes the toner discharging port 15.

9c is a recess formed on the bottom surface of the toner hopper 9, dividing the bottom surface into two. Further, the toner discharge roller 14 has a concave portion 9
It is stored in c. 16a and 16b are loop-shaped motion transmitting members such as belts, chains, lobes, etc.

The rotating shaft 19 is supported at both ends so as to be parallel to the toner discharge roller 14 . Sprockets 18a and 18b are fixed near both ends of this rotating shaft 19. The motion transmitting members 16a and 16b are sprockets 18a.

18b and the fixed shaft 19, and runs across the upper part of the toner discharging roller 14 in a direction perpendicular to the axis of the toner discharging roller 14. Here, a rotating shaft or a sprocket may be used instead of the fixed shaft 19. Reference numeral 20 denotes a stirring member arranged substantially parallel to the rotating shaft 19 and having both ends attached to the motion transmitting members 16a and 16b, and is shaped like a round bar. The sprockets 18a, 18b and the toner discharge roller 14 are connected to an idler gear 23.2 by a motor 22, such as a stepping motor, disposed on the chassis 21 of the machine body.
4.25.

The sprocket gear 26 and toner discharge roller gear 27 are driven by the motor 22, thereby rotationally driving the sprockets 18a, 18b and the toner discharge roller 14. A developer mixer 28 is disposed in the developing vat 12 and stirs and mixes the toner 8 supplied from the toner hopper 9 through the toner discharge port 15 and conveys it to the developing sleeve 29. The transported toner 8 and carrier 10 are transferred to a magnetic roller 29 fixedly disposed within the developing sleeve 11.
A magnetic brush is formed by the magnetic force of the developing sleeve 11, and its height is limited by the doctor blade 30.
As the magnetic brush rotates, the magnetic brush comes into contact with the photoreceptor l, and the photoreceptor l
Toner 8 is attached to the electrostatic latent image portion to form a powder image. 31 is a toner concentration sensor for detecting the mixing ratio of toner 8 and carrier 10;
is attached to. 32 is a developing section where development is performed.

FIG. 3 is a block diagram of the main parts of the circuit of the electrophotographic apparatus of the present invention. In FIG. 3, reference numeral 33 denotes a control device including a microcomputer, and a toner concentration sensor 31 is connected to an input terminal. 34 is a driver for the motor 22, and is connected to an output terminal of the control device 33.

A power source 35 supplies power to the control device 33 and the driver 34.

Next, the operation of the above configuration will be explained. First, a corona discharge is caused by a charging wire 3 in a charger 2 connected to a high voltage power source, and the surface of the photoreceptor 1 is uniformly charged to about -600V to -700V. Next, the photoreceptor 1 is rotated in the direction of arrow E and the exposure light beam 6 is irradiated onto the uniformly charged surface of the photoreceptor 1.
The charge disappears from the irradiated area and an electrostatic latent image is formed. on the other hand,
The carrier 10 and toner 8 in the developing vat 12 are sufficiently triboelectrically charged by the developer mixer 28 , attracted by the magnet roller 29 , and conveyed to the developing section 32 by the rotation of the developing sleeve 11 . In this developing section 32, the carrier 10
The toner 8 forms a magnetic brush and contacts the photoreceptor l.

At this time, when a potential difference is applied between the developing sleeve 11 and the photoreceptor 1, the toner 8 is attached to the electrostatic latent image portion on the photoreceptor 1 to form a visible image, and the development is completed.

The operation of the electrophotographic apparatus of the present invention will be described below with reference to the flowchart shown in FIG. In step a, the mixing ratio of carrier 10 and toner 8 is constantly sensed by toner concentration sensor 31. When the toner 8 adheres to the photoreceptor 1 in the developing section 32 and is consumed, when the toner concentration sensor 31 detects that the mixture ratio of the carrier 10 and the toner 8 in the developing vat 12 is lower than a certain value, step b is performed. Then, the motor 22 is rotated forward at a predetermined number of rotations. As a result, the driving force of the motor 22 rotates the toner discharge roller 14 via various gears 23, 24, 25, 26, 27, and the toner discharge port 15.
The toner 8 in the toner hopper 9 is passed through the developing vat 1.
Replenish the developer onto the developer mixer 28 in 2. motor 22
When the motor 22 rotates forward at a predetermined number of rotations, the process proceeds to step C, where the motor 22 is rotated in the reverse direction at a predetermined number of rotations. After the motor 22 is reversely rotated by a predetermined number of rotations, the process proceeds to step d, where it is checked whether or not the toner in the toner hopper 9 has run out, and if the toner has run out, the operation is terminated. If the toner has not run out, the process proceeds to step e, and it is checked whether the toner concentration in the developing vat 12 has recovered to the set value. If the toner density has not recovered to the set value, the process returns to step b; if the toner density has recovered to the set value, the process returns to step a. In this way, the toner concentration in the developing vat 12 is restored to the set mixing ratio, and a constant mixing ratio is maintained.

In the developing device of the present invention configured as described above, the toner 8 in the toner hopper 9 is initially in the F state, and simultaneously with the rotation of the toner discharge roller 14, the power of the motor 54 is applied to the rotating shaft 17. The motion transmitting members 16a and 16b are connected to the rotating shaft 17 and the fixed shaft 1 through the sprockets 18a and 18b.
Rotate in a loop between 9. Accordingly, the stirring member 20
G along the entire bottom surface of the toner hopper 9 in a direction perpendicular to the axial direction of the toner discharge roller 14
While crossing the vertical upper part of the toner 8, the toner 8 is agitated and pushed toward the toner discharge roller 14 (in the H direction). As a result, the amount of toner above the toner discharge roller 14 gradually decreases. After the motor 22 has rotated a predetermined number of revolutions, the direction of rotation is reversed, so toner is not blocked at a specific location within the toner hopper.

In the above embodiment, the direction of rotation of the motor 22 is reversed after the motor 22 has rotated a predetermined number of revolutions, but the direction of rotation of the motor 22 may be reversed every time the stirring member 20 rotates once. However, after rotating the motor 22 for a predetermined period of time, the direction of rotation of the motor 22 may be reversed. Furthermore, the rotation direction may be reversed each time the motor 22 is started.

Effects of the Invention As described above, the present invention divides the bottom surface of a toner hopper by a recess having a toner discharge port, stores a toner discharge roller that blocks the toner discharge port in the recess, and transfers the bottom surface divided by the recess from one side to the other. Since we provided a stirring member that moves toward the direction of the toner by passing over the recess and a control means that changes the direction of movement of the stirring member during operation, toner that adheres to the surface of the toner discharge roller and does not fall from the toner discharge port is removed. Even if the toner returns to the toner hopper, the agitating member returns the toner to the concave portion, preventing the toner from accumulating in the toner hopper due to the blocking phenomenon.

Therefore, almost all of the toner stored in the toner hopper can be used, and the toner in the toner hopper is not wasted. Furthermore, since the capacity of the toner hopper is fully used, the interval between toner replenishment can be extended.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the electrophotographic apparatus of the present invention, FIG. 2 is a perspective view of a portion of the toner hopper, FIG. 3 is a circuit block diagram of the main part, and FIG. 4 shows the same operation. 5 is a side view of the conventional electrophotographic apparatus, and FIG. 6 is a perspective view of the toner hopper portion of the same. l...Photoreceptor 2...Charger 3...
Charged wire 4... Shield plate 5... Grid plate 6.
・・Exposure light beam 7・Developing bag M 8・Toner 9・
... Toner hopper 10 ... Carrier 1
1...Developing sleeve 12...Developing vat 13
... Toner hopper lid 14 ... Toner discharge roller
15... Toner discharge port 9b... Concave portion 16a
, 16b...Motion transmission member 17...Rotating shaft 18
a, 18b... Sprocket 19... Fixed shaft 20
... Stirring member 21 ... Chassis 22 ... Motor 23.24.25 ... Idler gear 26 ... Sprocket gear 27 ... Toner discharge roller gear 28 ... Developer mixer 29 ... Magnet roller 30...Doctor blade 31...Toner concentration sensor 32...Name of developing department agent Patent attorney Toshio Nakao and 1 other person No. 5
Figure A
C? ″in

Claims (1)

[Claims] A recess is formed in the bottom of the hopper for storing toner so as to divide the bottom, a toner discharge port is formed in the bottom of the recess, and the toner discharge port is closed and rotated to remove the toner adhering to the surface from the discharge port. A toner discharging roller to be discharged is housed in the recess, and a stirring member is provided that moves across the recess from one bottom surface of the hopper to the other and returns to one of the bottom surfaces again, and the toner discharging roller and the stirring member are provided. An electrophotographic apparatus, characterized in that it is provided with a control means for controlling the moving direction of the electrophotographic apparatus to be changed while the electrophotographic apparatus is in operation.