JPH01282579A - Electrophotographic copying device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic device in which an electrostatic latent image formed on a photoreceptor is visualized using toner particles, transferred to paper, and fixed by heat or pressure. It is something.

Conventional technology Until now, most electrophotographic devices have been devices that use dry toner, and have been put into practical use as copiers, laser printers, etc.This electrophotographic device is a device that applies electrophotographic process technology. , an electrostatic latent image formed on a photoreceptor is developed using toner particles.Electrophotographic devices that employ a two-component development method that uses a mixture of toner and carrier as a developer are generally filled with a developer. It has a developing vat and a toner hopper that stores toner for replenishment.The toner in the toner hopper falls into the developing vat by the rotation of the toner discharge roller, so that the mixture ratio of toner and carrier in the developing vat is always constant. The toner filled in the toner hopper decreases as it is used, and some of the toner may adhere to the inner wall of the toner hopper and cause toner blocking (solidification). When toner remains in the toner hopper, the volume of the toner hopper is substantially reduced.

Therefore, various attempts have been made to reduce the amount of toner remaining in the stagnation area and to completely replenish the toner in the toner hopper to the outside.

A conventionally employed electrophotographic apparatus will be described above with reference to the drawings.

FIG. 3 is a side view of a conventional electrophotographic apparatus, and FIG. 4 is a perspective view of a portion of a toner hopper of the conventional electrophotographic apparatus. In FIGS. 3 and 4, reference numeral 1 denotes a photoreceptor which is made of a tube made of aluminum or the like, and has a thin film coated with a photosensitive layer such as selenium (Se) or organic photoconductor (OPC) 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 and a grid plate 5 made of sheet metal. By applying a high voltage to the charging wire 3, the charging wire 3 causes corona discharge, and the photoreceptor is uniformly charged via the grid plate 5. 6 is an exposure light beam emitted from an optical unit (not shown).

When an electrophotographic device is used in a copying machine, the exposure light beam is a reflected light beam from a document, and when an electrophotographic device is used in a laser printer, the exposure light beam is an image data beam. In the case of a laser printer, the exposure beam 6 is controlled by signals from a host computer (not shown), and the desired image is formed on the photoreceptor 1 as an electrostatic latent image. A developing device 7 includes a toner hopper 9 for storing toner 8 and a developing vat 12. The developing vat 12 stores toner 8 and carrier 10 which is magnetic particles such as iron powder. After the carrier 10 and toner 8 are mixed and stirred, they are conveyed to a developing sleeve 11 to form a magnetic brush. 13 is a toner hopper lid. Reference numeral 14 denotes a toner discharge roller whose both ends are rotatably supported within the toner hopper 9 . The toner discharge roller 14 blocks the toner discharge port 15 of the toner hopper 9, and as the toner discharge roller 14 rotates, the toner adhering to the surface of the toner discharge roller 14 is removed from the toner discharge port 1.
It is discharged from 5. 16a and 16b are loop-shaped motion transmitting members such as belts, chains, ropes, etc.
It is arranged at both ends of 7. Motion transmission member 16a, 1
6b is a sprocket 18a fixed to a rotating shaft 17 whose both ends are supported so as to be parallel to the toner discharge roller 14;
, 18b and the fixed shaft 19. Then, it runs in a direction perpendicular to the axis of the toner discharging roller 14 so as to cross the upper part of the toner discharging roller 14 . 2o is the rotation axis 1
7, and both ends are connected to rotating members 16a, 16.
This is a round bar-shaped stirring member attached to b. The sprockets 18a, 18b and the toner discharge roller 14 are connected to a drive source 22, such as a stepping motor, disposed on a chassis 21 of the machine body via an idler gear 23.24.25. Further, a sprocket gear 26 and a toner discharge roller gear 27 are also connected to the drive source 22 via idler gears 23, 24, and 25. A developer mixer 28 is disposed within the developing vat 12 and stirs and mixes the toner 8, and conveys the mixed toner to the developing sleeve 11. Conveyed toner 8
The carrier 10 is formed into a magnetic brush by the magnetic force of a magnet roller 29 fixed within the developing sleeve 11, 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 the toner 8 is attached to the electrostatic latent image portion of the photoreceptor 1 to form a powder image. 31 is a toner concentration sensor for detecting the mixing ratio of toner 8 and carrier 10, and is attached to doctor blade 30. 32
is a developing section that performs development.

Next, the operation of the above configuration will be explained. First, a corona discharge is performed 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 six directions of the arrows 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 sufficiently frictionally charged by the developer mixer 28 and the magnetic roller 29
is sucked into the developing section 3 by rotation of the developing sleeve 11.
2. In this developing section 32, the carrier 10 and the toner 8 form a magnetic brush and come into contact with the photoreceptor 1. At this time, when a potential difference is applied between the developing sleeve 11 and the photoreceptor 1, the toner 8 adheres to the portion of the photoreceptor 1 where the electrostatic latent image is formed, forming a visible image, and the development is completed. Career 1 here
The mixing ratio of toner 8 and toner 8 is constantly detected by a toner concentration sensor 31. The toner 8 is applied to the photoreceptor 1 in the developing section 32.
When the toner concentration sensor 31 detects that the mixture ratio of carrier 10 and toner 8 in the developing vat 12 is lower than a certain value, the detection signal is transmitted to a microcomputer (not shown). ). Then, as shown in Figure 4, the microcomputer
The driving force of the drive source 22 is transmitted to the toner discharge roller 14 via idler gears 23, 24, 25, sprocket gear 26, and toner discharge roller gear 27.
and rotates the toner discharge roller 14. As a result, the toner 8 in the toner hopper 9 is replenished onto the developer mixer 28 in the developing vat 12 through the toner discharge port 15 to restore the set mixing ratio and 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 a state shown by line B. Simultaneously with the rotation of the toner discharge roller 40 by the power of the drive source 22, the motion transmission members 16a and 16b rotate in a loop between the rotary shaft 17 and the fixed shaft 19. Accordingly, the agitating member 20 stirs the toner 8 along the entire bottom surface of the toner hopper 9 in a direction perpendicular to the axial direction of the toner discharging roller 14 while crossing the upper part of the toner discharging roller 14 . (in the direction of arrow H). However, since the bottom surface of the toner hopper 9 is configured to have the same height over almost the entire area, the toner 8 on the bottom surface 9a is pushed by the stirring member 20, adheres to the stirring member 20, and passes over the toner discharge roller 14. ,
It had accumulated on the bottom surface 9b as shown in section E. Therefore, the toner 8 remained in the toner hopper 9, and the volume of the toner hopper 9 was substantially reduced.

Means for Solving the Problems The present invention eliminates the above drawbacks by forming a low height part and a high part on the bottom of the toner hopper, and providing a toner discharge port at the boundary between the low height part and the high height part. The toner hopper is provided with a toner discharge roller that closes the toner discharge port, and a stirring member is provided that runs across the upper part of the toner discharge roller and runs from the lower bottom surface to the higher bottom surface of the toner hopper.

Operation By the above means, the direction of movement of the stirring member changes upward above the toner discharge roller. Therefore, acceleration is applied to the stirring member above the toner discharge roller, and the toner adhering to the stirring member is dropped onto the toner discharge roller by the acceleration.

Example Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

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

In FIG. 1 and FIG. 2, the parts given the same numbers as those in the conventional example are the same as those in the conventional example, and therefore the description thereof will be omitted.

In FIGS. 1 and 2, the bottom surface of the toner hopper 9 is divided into two by a toner discharge port 15, and one bottom surface 9b is formed higher than the other bottom surface 9a. Further, the stirring member 20 is configured to move along the lower bottom surface 9a, then gradually move upward, pass the upper part of the discharge roller 14, and then move along the higher bottom surface 9b.

Next, the operation of the electrophotographic apparatus of the present invention configured as described above will be explained. First, while rotating the photoreceptor 1 in the direction of arrow E, a corona discharge is caused by the charging wire 3 in the charger 2 connected to a high-voltage power source to uniformly cover the surface of the photoreceptor 1 at a voltage of -600V to -
Charge it to about 700v. Next, when the exposure light beam 6 is irradiated onto the uniformly charged surface of the photoreceptor 1, the charge disappears in the irradiated area, and an electrostatic latent image is formed. - The carrier 10 and toner 8 in the visible image vat 12 are stored in the developer mixer 2.
8 and is sufficiently frictionally charged and attracted to the magnet roller 29, and as the developing sleeve 11 rotates, the developing section 32
transported to. In the developing section 32, the carrier 10 and the toner 8 form a magnetic brush and come into contact with the photoreceptor 1. 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. When the toner 8 adheres to the photoreceptor 1 in the developing section 32 and is consumed, the amount of toner in the developing vat 12 decreases. When the amount of toner in the developing vat 12 reaches a predetermined level, the toner concentration sensor 31 detects the amount of toner in the developing vat 1.
It is detected that the mixing ratio of the carrier 10 and toner 8 in the toner 2 has become lower than a preset value, and the detection signal is sent to a host computer (not shown). Then, the microcomputer outputs a control signal to start the drive source 22, and the rotational force of the drive source 22 is applied to various gears 23, 24, 25.
, 26, 27 to the toner discharging roller 14, causing the toner discharging roller 14 to rotate. Then, the toner adhering to the surface of the toner discharge roller 14 is removed from the toner discharge port 1.
5 and falls into the developing vat 12. This operation is continued until a predetermined mixing ratio of toner 8 and carrier 10 is reached.
A constant mixing ratio will be maintained. In the toner hopper 9, the toner 8 is initially in a state indicated by a line F. The driving force of the driving source 22 causes the toner discharge roller 14 to rotate and the rotating shaft 17 . sprocket 18a,
18b rotates, and the motion transmitting members 16a, 16b rotate in a loop between the rotating shaft 17 and the fixed shaft 19. Accordingly, the stirring member 20 first moves along the lower bottom surface 9a in the toner hopper 9, crosses the upper part of the toner discharge roller 14 while rising, and moves along the lower bottom surface 9b. As the stirring member 20 moves, the toner 8 is stirred and pushed toward the toner discharge roller 14.

When the amount of toner 8 decreases and the toner discharge roller 14 is exposed, the toner adhering to the stirring member 20 falls onto the toner discharge roller 14. Here, the stirring member 20
Since the toner is rising above the toner discharge roller 14, acceleration is applied to the agitating member 2o, making it easier to fall than the agitating member 20.

Effects of the Invention As described above, in the present invention, after the stirring member moves along the lower bottom surface of the toner hopper, it rises while crossing at least the upper part of the discharge roller, so that the toner adhering to the stirring member is removed from the discharge roller. Therefore, the toner adhering to the agitating member is less likely to pass through the upper part of the discharge roller, reducing the amount of toner that accumulates in the toner hopper.This makes the capacity of the toner hopper more effective. You can use it.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the electrophotographic apparatus of the present invention, FIG. 2 is a perspective view of a part of the same toner hopper, FIG. 3 is a side view of a conventional electrophotographic apparatus, and FIG. 4 is a side view of the same toner hopper. It is a partial perspective view. 1... Photoreceptor 2... Charger 3...
Charged wire 4... Shield plate 5... Grid plate 6.
...Exposure light beam 7...Developing device 8...Toner 9.
... Toner hopper 12 ... Developing vat
10...Carrier 11...Developing sleeve 13
... Toner hopper lid 14 ... Toner discharge roller
15... Toner discharge ports 16a, 16b... Motion transmission member 17... Rotating shafts 18a, 18b... Sprocket 19... Fixed shaft 20... Stirring member 2
1... Chassis 22... Drive source 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 ... Developing section substitute Name of person: Patent attorney Toshio Nakao and 1 other person 5---
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Claims (1)

[Claims] A part of the bottom of the toner hopper is formed lower than the other part, and a toner discharge port is placed at the boundary between the lower bottom and the higher bottom, and by blocking the toner discharge port and rotating, the toner adheres to the surface. A toner discharge roller is provided for discharging the toner from the toner discharge port, and the roller moves from the lower bottom surface to the higher bottom surface and along almost the entire surface of the lower bottom surface and the higher bottom surface. An electrophotographic apparatus characterized in that a stirring member is provided that returns above the lower bottom surface.