JPS60162272A - Developing device of copying machine - Google Patents

Abstract

PURPOSE:To prevent leak of a toner and to prevent dirt of a device by arranging plural magnetic poles, whose same poles face each other, close to each other in the edge part of an aperture part, where a developing vessel faces a photosensitive body, to form a magnetic shield. CONSTITUTION:A developing vessel 6 incorporates a developing roll 7 and the toner and faces a photosensitive body 5 through an aperture part 6a, and a trimmer 9 which controls a toner layer 7a to a prescribed quantity is provided above the toll 7. The developing vessel 6 consists of a nonmagnetic material such as plastics, aluminium, or the like, and a shield means 8 is provided in the end part of the developing vessel 6. In the figure, only the upper part of the developing vessel 6 is shown but the lower part is omitted. The shield means 8 consists of plural magnets 10a and 10b which are arranged on the inside and the outside at the end part of the vessel 6 so that the same poles are close to each other. A magnetic curtain is formed by the repulsive magnetic field in a space A between the developing vessel 6 and the photosensitive body. Thus, leak of the toner from the space A is prevented to prevent dirt of the inside of the copying machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device using magnetic component toner, and particularly to a developing device capable of preventing leakage of toner to the outside of a developing container.

[Prior art]

In the developing device of a copying machine, toner, which is a lightweight fine particle, is adsorbed to the developing roll installed in the developing container, so the toner easily scatters from the developing roll as the developing roll rotates. Floating inside the developer container. Then, this floating toner leaks out from the gap between the photoreceptor and the developing container and stains the inside of the machine, so a means for preventing this is required.

For this reason, conventionally, for example, developing devices using magnetic component toner have been proposed that are equipped with a toner leak prevention means as shown in FIG. That is,
In a developer container (2) that is provided close to the photoreceptor (1) and is open on the photoreceptor (1) side, this is applied to the outer wall surface of the developer container (2) along the opening edge of the developer container (2). magnet(
3) is attached, and the magnet (
3) to the magnetic pole portion (8a) and its vicinity, thereby preventing toner from leaking to the outside of the developer container (2).

However, this type of product is designed to attract floating toner, so if used for a long time,
A large number of toners are attracted to the magnetic pole part (3a) and its vicinity, and as a result, the suction force is reduced.
) Only the toner in the immediate vicinity can be adsorbed; other toner leaks outside, causing problems.

[Purpose of the invention]

The present invention aims to eliminate the above-mentioned problems in the conventional developing device of a copying machine. More specifically, by utilizing magnetic repulsion, the leakage of floating toner to the outside of the developing container is prevented. It is an object of the present invention to provide a developing device for a copying machine which can effectively prevent the output from occurring over a long period of time.

[Structure of the invention]

That is, the present invention provides a developing device for a copying machine in which a developing roll housed in a developing container is opposed to a photoreceptor through an opening provided in the developing container, and development is performed using a magnetic component toner. A shielding means consisting of a plurality of magnets having similar poles arranged close to each other is provided at the edge of the opening of the developer container, and the shielding means is provided in the gap between the developer container and the photoreceptor. (Formation of a magnetic shield (hereinafter referred to as a magnetic curtain) by two anti-1'f1 magnetic fields,
Thereby, the floating toner inside the developer container is sealed off by the magnetic curtain, and leakage to the outside of the developer container is prevented.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A developing device for a copying machine according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 2 shows a developing device for a copying machine to which the present invention is applied. A developing roll (7) housed in the developing container (6) and facing the photoreceptor (5) through the opening (6a), and a shielding means provided at the edge of the opening of the developing container (6). (8).

The developing roll (7) is composed of a sleeve (circuit) whose outer peripheral surface rotates in the opposite direction to that of the photoreceptor (5), and a plurality of magnets (circuits) fixed inside the sleeve,
The toner is magnetically attracted onto the sleeve, and the toner is layered (
7a) is formed.

The developer container (6) is made of a non-magnetic material such as aluminum or plastic, and a trimmer (9) is provided on the inner wall above the developer roll (7) to regulate the toner layer (7a) to a predetermined thickness. ) is provided.

The shielding means (8) is composed of a plurality of magnets with similar poles arranged close to each other along the opening edge of the developer container (6). An inner magnet (-) and an electromagnet (,1
Ob) are installed with their poles aligned. Therefore, the gap (A) between the developer container (6) and the photoreceptor (5)
A magnetic curtain (circuit) is formed by the repelling magnetic field between the north poles.

The shielding means (8) may be a magnet as shown in FIG. 4, for example, a bipolar magnet (such as Il+) in which the magnetic poles on the opening side of the developer container (6) are of the same type and have a bipolar structure. It is also possible to use

Further, the magnet used in the above-mentioned shielding means (8) of the present invention may be a permanent magnet, as long as a predetermined effect can be obtained.
Any electromagnetic method can be used, and there are no particular limitations.

Therefore, according to this embodiment, even if the toner scatters from above the rotating developing roll (7) during development and becomes floating toner, and heads towards the space (A) between the developing container (6) and the photoreceptor (5),
Since the shielding means (8) forms a magnetic curtain (circuit) in this gap (A) and magnetically seals off the floating toner o3, the floating toner o3 is repelled by the magnetic curtain and the developing container ( 6) No leakage outside.

Furthermore, even if development is carried out over a long period of time, the floating toner 02 does not adhere to the magnetic pole portion of the magnet that constitutes the shielding means (8) facing the photoreceptor (5) and its vicinity, so that the effect is not increased. Target (Can prevent leakage of Nitoner.

〔Effect of the invention〕

Since the present invention has the above-described configuration, it is possible to prevent toner from leaking over a long period of time, and it is possible to reliably prevent staining caused by toner inside the copying machine, and its effects are tremendous.

Further, since the present invention utilizes magnetic repulsion, toner is not attracted to the shield means, and maintenance management is easy.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a toner leak prevention means in a conventionally used developing device of a copying machine, FIG. 2 is a schematic sectional view of a developing device of a copying machine to which the present invention is applied, and FIG.
The figure is an enlarged sectional view of the main part of FIG. 2, and FIG. 4 is a schematic sectional view showing a modification of the shielding means according to the present invention. Code explanation fi+ +51... Photoreceptor (21 (61...
...Developer container (3) ... Magnet (7) ...
... Developing roll (8) ... Shield means (10a) (, 10b) ... Inner magnet, outer magnetic surface (
11) ... Bipolar magnet Zero ... Floating toner (A) ... Gap Patent applicant Fuji Xerox Co., Ltd. Agent Tomohiro Donakamura, patent attorney Katsuo Naruse No. 1 Figure 2

Claims (1)

[Claims] In a developing device that performs development using a magnetic component toner by arranging a developing roll housed in the developing container to face a photoreceptor through an opening provided in the developing container, an opening edge of the developing container is provided. 1. A developing device for a copying machine, characterized in that said developing device is provided with a shield means comprising a plurality of magnets having similar poles arranged close to each other.