JPS61281269A - Single component developing device - Google Patents

Abstract

PURPOSE:To execute clear development without impression of an alternating current bias and fogging by building in a rotating magnet at the part to face to a developing sleeve of a static latent image holding body. CONSTITUTION:Even at the part to face to a developing sleeve 3 of a photosensitive body drum 1 formed by a non-magnetic member, the second magnet roller 6 constructed in the same way as the first magnet roller 4 is freely rotatably built in. Both magnet rollers 4 and 6 are constructed so that the circumferential side part can run counter, and when these magnet rollers 4 and 6 are rotated, the magnetic flux density is changed. Consequently, when the developing sleeve 3 and both magnet rollers 4 and 6 are rotated, a developing powder 7 transported up to the developing area by the developing sleeve 3 vibrates at the developing area and is stuck to the part where the static latent image of the photosensitive body drum 1 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION B) Field of Industrial Application The present invention relates to a developing device that develops an electrostatic latent image using only a one-component developing agent without using a so-called carrier.

(b) Conventional technology The developing device uses a one-component developer and is fixed f'.
A type in which a magnet rotates inside a non-magnetic developing sleeve (JP-A-58-66975, JP-A-56-1220)
66) and a type in which a non-magnetic developing sleeve is rotatably fitted onto a fixed nt magnet (see Japanese Patent Publication No. 58-32375).

(c) Problems to be Solved by the Invention Fixed f'Lt In a developer bag @ in which a magnet rotates inside a non-magnetic developer sleeve, the developer is likely to vibrate and be agitated, making it difficult to transport the developer. Not enough.

There is an advantage that the electrostatic latent image is sufficiently supplied with developer.

However, it is difficult to form a thin layer of developer on the developing sleeve, and so-called capri is likely to occur.

In a developing device in which the t% is fixed and a non-magnetic developing sleeve is rotatably fitted to a magnet, a thin layer of developer can be easily formed, but the developer vibrates in the developing area. However, there was a problem in that sufficient development could not be achieved unless an alternating current bias was applied.

The present invention is a developing device that forms a thin layer on the developing sleeve and can vibrate the developer in the developing area.

2) Means for Solving the Problems The present invention is characterized in that the electrostatic latent image carrier is formed of a non-magnetic material, and that the electrostatic latent image carrier is formed of a non-magnetic material. This is a one-component developing device characterized by a built-in magnet.

(E) Operation When the magnet built into the electrostatic latent image carrier rotates, the developer vibrates in the portion of the developing sleeve that faces the electrostatic latent image carrier.

(f) Example FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In this figure, (11 is the circumference of the aluminum Ecum cylinder)
An electrostatic latent image is formed on a photoreceptor drum, which serves as an electrostatic latent image carrier, and has a photoconductive layer of amorphous silicon or the like footed on its surface by a means (not shown).

[2] is the main body of the developing device, with an opening formed in the part facing the photoreceptor drum +11, and a cylindrical developing device made of a non-magnetic material P+ such as aluminum at the opening. A sleeve 111 is rotatably attached.

In addition, the developing sleeve 1jlltl! It should rotate at 70'rpm.

It is connected to a motor (not shown).

Inside the developing sleeve [31], magnets are arranged as rotating magnets so that different magnets a appear alternately on the surface, and a first magnetic roller (4) in the shape of a cylindrical cylinder can rotate freely once. The ζO magnet roller (4) is configured to rotate clockwise by a driving means (not shown).

A magnetic doctor grade (61) is provided on the top of the developing sleeve (3). A positive bias voltage is applied to the developing sleeve IjllK.

A second magnet roller (6) having the same structure as the first magnet roller (4) is also rotatably built in a portion of the photoreceptor drum +1) facing the developing sleeve +3+ 1c.

The first magnet roller a) and the second magnet roller (6) are configured to rotate at the same rotation speed in opposite directions.

The developer (7) is made by mixing plastic particles such as polystyrene with a pigment such as carbon and a magnetic member such as ferrite.

Fig. 2 is a developed view of the parts where the two magnetic rollers (4) (υ) approach each other. When these magnetic rollers (4) (υ) rotate, their magnetic flux density changes as shown in FIG.

Therefore, the developing sleeve (6) and both magnetic rollers (a)
) (6) rotates, the developer gun conveyed to the developing area by the developing sleeve etc.) vibrates in the developing area and hits the part of the photoreceptor drum (1) where the electrostatic latent image is formed. adhere to.

FIG. 4 is a schematic configuration diagram showing another embodiment.

This embodiment differs from the previous embodiments in that the electrostatic latent image carrier is composed of a photoreceptor belt (8), and the second magnetic roller (
6) serves as an idler for this photoreceptor belt (8). The structure of the developing device main body V) is the same as that of the previous embodiment.

The photoreceptor belt (8) is a flexible plastic belt on which a conductive layer and a photoconductive layer are laminated.

In the present embodiment, the first magnet roller (4) is rotatably inserted into the developing sleeve (3), but the first magnet roller (4) does not necessarily have to be present. , developer V) vibrates in the development area.

(G) Effects of the Invention In the present invention, since a rotating magnet is built in the portion of the static latent image bearing member that faces the developing sleeve, the developer vibrates in the developing area and an alternating current bias is applied. without any
Clear development without capri can be performed.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing the first embodiment, Fig. 2 is an exploded view of the main parts, Fig. 6 is a graph showing changes in magnetic flux density, and Fig. 4 is a graph showing changes in magnetic flux density.
The figure is a schematic configuration diagram showing a second embodiment. (1)...Photosensitive drum (electrostatic latent image carrier), ■01
．． Developing device main body, (b)...Developing sleeve, (4) (
6)... Magnet roller (rotating magnet), (8)... Photosensitive belt (electrostatic latent image carrier).

Claims (1)

[Claims] 1. A developing device that is provided with an electrostatic latent image carrier and a cylindrical developing sleeve that holds a magnetic one-component developer and conveys it to the electrostatic latent image carrier. In the apparatus, the electrostatic latent image carrier is formed of a non-magnetic material, and a rotating magnet is built in a portion of the electrostatic latent image carrier that faces the developing sleeve. One-component developing device. 2. The one-component developing device according to claim 1, wherein the developing sleeve has a built-in rotating magnet. 3. The one-component developing device according to claim 1 or 2, wherein the rotating magnet is formed of a cylindrical body in which different magnetic poles alternately appear on the circumferential surface.