JPS59229583A - Developing method of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To enable development of longitudinal and lateral lines to almost equal line width and to enhance development efficiency by alternately arranging magnets different in polarity from each other under the photosensitive layer of a photosensitive drum so as to incline the direction of each magnet to a generation line of the drum. CONSTITUTION:Plural N pole and S pole magnets are arranged alternately and slantly to the generation line of a photosensitive drum 1, under the photosensitive layer 2 to form a cylindrical magnet layer 3. The magnetic force distribution of the surface of the layer 2 provided with the layer 3 under it inclines to the radial direction of the drum 1. The drum 1 and a magnetic roll 4 rotate in the arrow directions, respectively, and when a magnetic brush 5 formed on the roll 4 develops an electrostatic latent image, the magnetic force distribution on the drum 1 changes every moment with its rotation, resulting in activating the movement of the developer forming the magnetic brush. As a result, development can be carried out in equal line width of both longitudinal and lateral lines, and development efficiency can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developing system for an electrophotographic copying machine, and more specifically, to a developing system using a photoreceptor with high developing efficiency.

BACKGROUND TECHNOLOGY In general, in magnetic brush development, a magnetic brush is formed on a cylindrical sleeve made of non-magnetic material containing a plurality of magnets, and in the case of a two-component developer, toner is attached to a chain of carriers. In addition, in the case of a component developer, a magnetic brush consisting of a chain of toner is formed, and such magnetic brush comes into contact with the electrostatic latent image on the surface of the photoreceptor and develops it. There is. Toner particles of a magnetic brush formed on a magnetic roll such as a magnet and a cylindrical sleeve are attached in a chain on the surface of the magnetic roll under the action of the magnetic force of the magnetic roll. The movement of the magnetic roll in the radial direction and generatrix direction is small, so when the magnetic brush comes into contact with the photoconductor surface, toner particles pass through without contributing to the development of the electrostatic latent image on the photoconductor surface. There was a considerable amount of deterioration, and high development efficiency could not be obtained. For example, there is a difference in development efficiency between an electrostatic image parallel to the circumference of the photosensitive drum and a static 1JL latent image perpendicular to this (generating line direction of the photosensitive drum). The image (vertical image) tends to be developed thickly, and the image in the direction perpendicular to this (horizontal image) tends to be developed thinly, and the aspect ratio of the line width of the developed image is 1.1 to 1.2: It was 1.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a developing system that does not cause such a difference in aspect ratio and can achieve development with substantially equal line widths in both the vertical and horizontal directions.

Structure of the Invention The object of the present invention is achieved by alternately arranging magnets having different polarities under the photosensitive layer of the photosensitive drum so as to be diagonal to the generatrix of the photosensitive drum.

The present invention will be described in detail below with reference to the drawings. In FIG. 1, 1 is a photosensitive drum, and a plurality of N-pole and 8-pole magnets are alternately arranged under a photosensitive layer (2) to form a cylindrical magnetic layer (6). are doing. Second
The figure shows the state of this magnet layer, in which N-pole magnets and S-pole magnets are arranged alternately and obliquely along the generatrix of the cylinder. Therefore, the distribution of magnetic force in the cylindrical magnet layer is biased in the radial direction of the cylinder, and therefore the distribution of magnetic force on the surface of the photosensitive layer on the back side of which this cylindrical magnet layer is provided is also biased in the radial direction of the photosensitive drum. It turns out.

According to the present invention, the photosensitive drum (1) and the magnetic roll (
4) rotate in the directions of the arrows, and when the magnetic brush (5) on the magnetic roll develops the electrostatic latent image on the surface of the photosensitive drum, the distribution of magnetic force on the photosensitive drum changes moment by moment as the photosensitive drum rotates. As a result, the behavior of the developer forming the magnetic brush is activated, and the development efficiency is therefore increased. That is, according to the present invention, the vertical to horizontal line width ratio of the developed image is about 1:1, and the developing efficiency is increased by 10 to 20 q6 compared to the conventional magnetic brush development, and excellent copies can be obtained.

Effects of the Invention According to the present invention, the behavior of toner particles in the magnetic brush is activated during the development process, and the vertical and horizontal line width ratio of the developed image is increased by 10 to 20 inches compared to conventional magnetic brush development, resulting in high development efficiency. You can get

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the present invention, and FIG. 2 is a diagram showing a cylindrical magnet layer according to the present invention.

Claims (1)

[Claims] A developing system for an electrophotographic copying machine, characterized in that a plurality of magnets having different polarities are alternately arranged under a photosensitive layer of a photosensitive drum so as to be diagonal to the generatrix of the photosensitive drum.