JPH0588537A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the splashing of a toner. CONSTITUTION:The developing device 1 having a magnet roller 2 and a toner supplying and recovering roller 10 facing the outer periphery in the lower part of this magnet roller 2 apart a slight spacing is provided with a biasing means 18 which positions the top end of a sheet 15 to be vibrated by impression of AC thereto near a developing region, is provided to a nonconductive member 16 on the sheet 15 and brings the sheet 15 into contact with the toner supplying and recovering roller 10 via this nonconductive member 16 and a biasing means 18 for impressing the AC to the sheet 12 so that the toner captured and dropped onto the sheet 15 is recovered to the toner supplying and recovering roller 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, an electrostatic latent image is formed by contacting a developer, which has a magnet body and a sleeve which is covered with the magnet body, with a developer consisting of toner and a carrier held on the outer circumference of the sleeve. As a developing device for developing, a toner supply / collection roller having minute irregularities on the outer peripheral surface and facing the sleeve at a minute interval is provided, and at the facing portion of the roller and the sleeve, the surface of the roller is provided. It is known that the held toner is supplied to the sleeve and the excess toner in the developer held on the surface of the sleeve is collected by a roller.

Although not limited to the above-mentioned developing device, in the developing device for developing by bringing the developer into contact with the photoconductor, scattering of the toner separated from the developer held on the outer peripheral surface of the sleeve is prevented. In order to do so, a toner receiving member is provided below the facing portion between the photoconductor and the developing device, so that the fall toner is collected.

[0004]

However, the toner accumulated in the toner receiving member may drop due to vibrations when the developing device is attached or detached, or vibrations when the image forming device is moved, and the peripheral devices may be contaminated. However, there is a problem that it is not easy to collect the toner accumulated in the toner receiving member.

[0005]

Therefore, according to the present invention, in a developing device having the toner supply / collection roller, the upper end of a thin plate vibrating when an alternating current is applied is provided in the vicinity of a facing portion between the photoconductor and the magnet roller. And a non-conductive member is provided on the thin plate, and the thin plate is brought into contact with the toner supply / collection roller via the non-conductive member, and biasing means for applying an alternating current to the thin plate, Is provided.

[0006]

According to the above construction, the toner separated from the developer held on the outer periphery of the magnet roller and falling is captured by the thin plate. On the other hand, the thin plate vibrates when an AC bias is applied, and the vibration causes the contact between the non-conductive member and the toner supply / collection roller to change little by little. Therefore, the toner captured by the thin plate moves toward the outer peripheral surface of the toner supply / collection roller while being guided by the thin plate, and is collected by the toner supply / collection roller at the contact portion of the non-conductive member.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the developing device 1 shown in FIG. 1, the magnet roller 2 arranged to face the photoconductor 100 includes a fixed magnet body 3 having a plurality of magnetic poles on the outer peripheral portion, and the magnet body 3.
And a sleeve 4 that is rotatably driven in the direction of arrow a, and a blade 5 is opposed to the outer peripheral surface of the upper portion with a predetermined minute gap. The outer peripheral surface of the upper portion of the magnet roller 2 is covered with a cover 6, and a film sheet 7 provided at the tip of the cover 6 is brought into contact with the photoconductor 100.

The developer supply vane 8 is a magnet roller 2
It is housed in a developer mixing and stirring chamber 9 provided at the rear part (on the left side in the drawing) and is driven to rotate in the direction of arrow b. The developer mixing and stirring chamber 9 contains a developer consisting of toner and carrier. Has been done.

The toner supply / collection roller 10 is a cylindrical body having minute recesses formed on its outer peripheral surface by blasting or the like, and is arranged so as to face the lower outer peripheral surface of the magnet roller 2 and is driven to rotate in the direction of arrow c. is there. Further, a blade 11 is arranged at the rear part of the toner supply / collection roller 10, its tip is in contact with the outer peripheral surface of the roller, and a toner recovery device 12 is arranged at the front part.

As shown in FIG. 2, the toner collecting device 12 comprises a supporting member 14, a thin plate 15, and a sealing material 17. The support member 14 is made of an insulating material and stands up from the lower casing 13 of the developing device 1,
It passes between the toner supply / collection roller 10 and the photoconductor 100 and extends near the facing portion of the magnet roller 2 and the photoconductor 100. The thin plate 15 is made of, for example, stainless steel or phosphor bronze having spring properties and conductivity, is obliquely supported by the support member 14, and the lower end portion covered with a dielectric 16 such as Teflon tape supplies toner. An AC bias V (AC) is applied between the toner supply / collection roller 10 and the toner supply / collection roller 10 by being in contact with the outer peripheral surface of the collection roller 10. The seal member 17
Are supported by the lower casing 13 and have their upper ends in contact with the thin plate 15 via the dielectric 16.

The stirring blade 19 is arranged in a buffer 20 facing the outer peripheral surface of the rear portion of the toner supply / collection roller 10 so as to be rotatable in the direction of the arrow d. The toner is replenished based on the rotation in the direction of arrow e.

In the developing device 1 having the above structure, the toner in the buffer 20 moves toward the outer peripheral surface of the toner supply / collection roller 10 while being stirred by the stirring blade 19.
The toner is supplied to the minute peripheral recesses of the toner supply / collection roller 10. The toner held in the minute recesses is supplied with toner.
It is conveyed in the direction of arrow c with the rotation of the collection roller 10, and after the conveyance amount is regulated by the blade 11, it is supplied to the magnet roller 2 in the supply area 23.

On the outer periphery of the magnet roller 2, a developer consisting of toner and carrier is held in a magnetic brush state,
It is conveyed in the direction of arrow a along with the rotation of the sleeve 4,
In the supply area 23, the toner is replenished to the toner-deficient portion of the developer, and the excess toner in the developer is collected by the toner supply / collection roller 10. The supply / collection here is efficiently performed by the vibration action based on the AC bias V (AC) applied to the toner supply / collection roller 10. Then, the toner collected by the toner supply / collection roller 10 is conveyed in the direction of arrow c as the roller 10 rotates, passes through the contact portion of the dielectric 16, and is conveyed into the buffer 20. On the other hand, the toner supplied to the magnet roller 2 is conveyed in the direction of the arrow a together with the magnetic brush developer, is separated from the surface of the sleeve 4 at the portion facing the stirring chamber 9, and the stirring blade 8 is rotated to rotate the stirring chamber. The toner newly mixed with the developer No. 9 and newly supplied is uniformly dispersed in the developer.

The developer agitated in the agitating chamber 9 is supplied to the magnet roller 2 by the agitating blade 8 and conveyed in the direction of the arrow a along with the rotation of the sleeve 4, and is regulated by the blade 5 with the photoreceptor 100. The electrostatic latent image is developed by moving to the facing portion (developing area), where it contacts the photoconductor 100. Further, the developer that has passed through the developing area is supplied to the supply area 23.
The toner is replenished in the amount consumed by the development.

In the developing device 1, the developer is the photosensitive member 10.
When the magnetic brush comes into contact with 0 and when the developer that has passed through the developing area gradually falls from the standing state to the sideways state,
Toner is separated and scattered from the developer. Also, from the developer held on the upper outer peripheral surface of the magnet roller 2,
In the same manner, the toner becomes dust and scatters. However, in the developing device 1, the toner that falls below the magnet roller 2 is collected by the toner collecting device 12, and the toner that rises as the dust is raised by the cover 6 and the film sheet 7.
This prevents leakage to the outside.

The toner recovery by the toner recovery device 12 will be described in detail. The falling toner is received by the thin plate 15 or the support plate 14 and drops along the surface thereof. At this time, the thin plate 15 has an AC bias V (AC).
The toner on the thin plate 15 quickly reaches the surface of the toner supply / recovery roller 10 because the toner is applied and vibrates in small steps in accordance with the frequency. Further, since the contact force of the dielectric 16 with respect to the toner supply / collection roller 10 changes little by little due to the vibration, the collected toner passes through the contact portion of the dielectric 16 without being restricted by the dielectric 16. Are collected in the buffer 20. Further, the toner in the buffer 20 is prevented from leaking to the outside by the seal plate 17. Therefore, the toner dropped from the developer held on the magnet roller 2 does not scatter around, and the inside of the image forming apparatus including the developing device 1 is kept clean.

In the above embodiment, an AC bias V (AC) is applied between the thin plate 15 and the toner supply / collection roller 10.
However, AC may be applied to the thin plate 15 from a single power source. Further, in the above embodiment,
The thin plate 15 is a conductive plate covered with a dielectric tape, but may be a metal film vapor-deposited on one surface of a resin film.

[0018]

As is apparent from the above description, in the developing device according to the present invention, the upper end of the thin plate vibrating when an alternating current is applied is located near the facing portion of the photoconductor and the magnet roller, and Provide a non-conductive member on the thin plate,
There are provided a toner collecting unit that brings the thin plate into contact with the toner supply / collection roller via the non-conductive member, and a bias unit that applies an alternating current to the thin plate.

Further, by adopting the above configuration,
Toner separated from the developer held on the outer periphery of the magnet roller and falling is captured by a thin plate. On the other hand, the thin plate vibrates when an AC bias is applied, and the contact of the non-conductive member with the toner supply / collection roller changes little by little, and the captured toner is efficiently collected by the toner supply / collection roller. It

Therefore, it is possible to keep the inside of the image forming apparatus clean without the toner separated and dropped from the developer held by the magnet roller being scattered to pollute the peripheral equipment. Further, the captured toner is automatically collected and does not need to be artificially processed, which facilitates maintenance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a developing device.

FIG. 2 is an enlarged cross-sectional view of a toner recovery device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Developing device, 2 ... Magnet roller, 10 ... Toner supply / collection roller, 12 ... Toner collection device, 14 ... Support plate, 15 ... Thin plate, 16 ... Dielectric material, 18 ... AC power supply, V
(AC) ... AC bias.

Claims (1)

[Claims] 1. A magnet roller facing the photoconductor,
A toner supply / collection roller located below the magnet roller and facing the magnet roller with a minute gap therebetween, and an upper end of a thin plate vibrating when an alternating current is applied, near the facing portion of the photoconductor and the magnet roller. And a non-conductive member is provided on the thin plate, and the thin plate is brought into contact with the toner supply / collection roller via the non-conductive member, and biasing means for applying an alternating current to the thin plate, A developing device comprising: