JPS63218980A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a developer from being accumulated and scattered onto a developer control body, by constituting the titled device so that the developer carried to the latent image holding surface by a rotary sleeve is subjected to a magnetic restriction by a magnet and a magnetic member. CONSTITUTION:A developer (a) is attracted by magnetic force to the outer peripheral part of a magnet roller 2 and forms a magnetic brush a'. In this case, a magnetic member 8 is also magnetized by the magnetic force of the magnet roller 2 and a part of the developer of the magnetic brush a' is attracted, and the curtain (b) of a thin developer drawing a tail in the shape of a waterfall is formed. In such a way, the developer is scarcely accumulated on the tip face 7a of a supporting member 7, and also, even if it is accumulated, its scatter is obstructed by the curtain (b) of the developer, therefore, the stain of a photosensitive body can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in a developing device that develops an electrostatic latent image formed on a latent image holding surface.

(Prior Art) In recent years, electrophotographic copying machines in which development and cleaning are performed in the same device have been put into practical use.

(Problems to be Solved by the Invention) This type of electrophotographic copying machine employs a magnetic plan developing device, but the portion of the photoreceptor that serves as an electrostatic latent image holding surface that is in contact with the magnetic plan when it is stationary is There is a problem with smudging by the developer in the magnetic brush, causing black band smearing in the image. As a result of research into this problem, we found that in addition to dirt that occurs at the contact area, there is also damage caused by the impact when the magnet roll of the magnetic plan device starts rotating. It was found that some of the developer that had accumulated on the tip surface of the photoreceptor was scattered and adhered to the photoreceptor. Contamination at the contact area can be solved by electrostatically adsorbing the developer, but no such measures can be taken to prevent the accumulated developer from scattering. It has been desired to develop a developing device that does not cause deposits or scattering.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to eliminate the accumulation or scattering of developer on the developer regulating body and to exhibit excellent developing characteristics with less fog. [Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a developing device in which a rotating sleeve and a rotary sleeve are provided in a developer storage container. A fixed magnet is disposed, a developer regulating body is disposed in front of a position where the rotating sleeve faces the latent image holding surface, and this regulating body includes a magnetic member that cooperates with the magnet.

(Function) The developer conveyed to the latent image holding surface by the rotating sleeve is magnetically restrained by the magnet and the magnetic member, thereby preventing it from scattering.

(Example) The present invention will be described below based on an illustrated example. In the figure, reference numeral 1 denotes a developer storage container, and a magnet roll 2 is accommodated within this developer storage container 1. This magnet roll 2 includes a magnet roll main body 3 as a magnetic force generating means formed by fixedly disposing permanent magnets (not shown), and a developer support that is fitted onto the outside of the magnet roll main body 3 and rotates around the magnet roll main body 30. It consists of a cylindrical rotary sleeve 4, which attracts and carries developer a on its outer periphery in a so-called magnetic plan a.
′ is formed. Further, the rotating sleeve 4 rotates counterclockwise to convey the developer a contained in the developer storage container 1 one after another in the circumferential direction. As developer a, a mixture of magnetic powder (called carrier) made of iron powder or the like and colored resin powder (called toner) is used, but since it is affected by the magnetic field of magnet roll 2, K It is a necessary condition for the developer to have at least magnetism. As the sleeve 4 rotates, the magnetic plan a' of the developer a is continuously conveyed and brought into sliding contact with the photoconductor surface 5a of the photoconductor 5, which serves as a latent image holding surface and faces the sleeve 4. It looks like this. After making sliding contact with the photosensitive surface 5aK, the magnetic bluff a/ is forcibly scraped off from the rotary sleeve by a scraping plate 6 and stirred with the developer a in the developer storage container 1.

Further, a developer regulating body 11 is provided at the lower edge of the opening of the magnetic brush exposure window 1a of the developer storage container 1 to regulate the height of the magnetic plan, that is, the thickness of the layer of developer a. . As shown in detail in FIG. 2, this developer regulator 11 includes a support member 7 made of a non-magnetic material such as aluminum;
A magnetic member 8 such as an iron piece attached to the wall of this support member 7
It is composed of.

Note that 9 shown in FIG. 1 is a developer hopper, and 0 is a developer replenishment roller provided at a developer replenishment port of the developer hopper 9.

Next, the operation of the above embodiment will be explained.

The developer a in the developer storage container 1 is magnetically attracted to the outer periphery of the magnet roll 2 to form a magnetic plan a'. At this time, since the magnetic member 8 is also magnetized by the magnetic force of the magnet roll 2, the supporting member 7 of the developer regulator 11
A part of the developer in the magnetic plan a', which has been regulated by the magnetic plan A', is attracted, and a thin curtain b of developer with a tail as shown in FIG. 2 is formed. Therefore, almost no developer is deposited on the tip surface 7a of the support member 7 of the developer regulating body 11, and even if it were to be deposited, the developer curtain b prevents it from scattering. Therefore, staining of the photoreceptor can be prevented.

In addition, since this curtain b of the developer rubs against the surface of the magnetic pixel a', the developer just before development is well charged by friction, resulting in effects such as being able to obtain a good image without fogging. It also demonstrates. Particularly when excessive developer is replenished, if only the conventional developer regulating body (corresponding to the support member 7 of the present application) is used, the fogging density will be 0.0 in the reflection density.
In contrast, when the developer regulating body 1 in which the support member 7 and the magnetic member 8 are attached to the wall surface of the present invention is adopted, the developer concentration is reduced to less than 0.02. do.

In the above-described embodiment, the magnetic member 8 is attached to the outer wall surface of the support member 7 as a banding plate having a rectangular cross section, but the present invention is not limited to this. Of course, the mounting position can also be modified in various ways.

Note that the most effective position of the magnetic member 8 is such that it slightly adsorbs the developer on the surface of the magnetic plan.

〔Effect of the invention〕

According to the present invention, almost no developer is deposited on the front end surface of the developer regulating body, and even if it were to be deposited, the developer curtain prevents the developer from scattering, so that the latent image is retained. It can prevent surface stains. Also,
Since the curtain of developer rubs against the surface of the magnetic plan, the developer immediately before development is triboelectrically charged, resulting in a seeding effect such that a good image without fogging can be obtained.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a schematic longitudinal sectional side view, and FIG. 2 is a partially enlarged view of FIG. 1. I...Developer storage container, 3...Magnet roll,
4...Developer support, 5a...Latent image holding surface, 7...
- Support member, 8... Magnetic member, 11... Development regulator, a... Developer. Agent Patent Attorney Nori Chika Yudo Norio Ogo

Claims (1)

[Claims] A rotating sleeve (4) that faces a latent image holding surface (5a) that moves while holding an electrostatic latent image and rotates while carrying a developer (a) on its surface; a magnet (3) that is fixedly installed in a fixed state and generates a magnetic field for magnetically restraining the developer (a) carried by the rotating sleeve (4); developer regulation for regulating the layer thickness of the developer (a) carried by the rotating sleeve (4) and conveyed to a position facing the latent image holding surface (5) while being magnetically restrained; Body (1
1), and a developer storage container (1) containing the rotating sleeve (4) and storing the developer (a) carried by the rotating sleeve (4), The body (11) magnetically cooperates with the magnet (3) and is carried by the rotating sleeve (4), and the latent image retaining surface (
5) A developing device comprising a magnetic member (8) that magnetically restricts the scattering of the developer (a) that is conveyed to a position opposite to the developer (a).