JPS61158358A - Developing device - Google Patents

Abstract

PURPOSE:To execute efficient development and to stabilize a reproduced picture by providing the titled device with a rotatable multi-magnetic pole sleeve whose N and S magnetic poles are alternately arranged in its circumferential direction and a multi- magnetic pole magnet arranged in the multi-magnetic pole sleeve and forming respective N and S magnetic poles alternately in its circumferential direction. CONSTITUTION:Developer 11 adsorbed to the multi-magnetic pole sleeve 8 is carried in the rotational direction of the sleeve 8 and regulated at a fixed brush height by a magnetic blade 12 and the regulated developer 11 is carried to the most adjacent part between a photosensitive body 7 and the magnetic blade 12. The line of magnetic force formed by the sleeve 8 and the multi-magnetic pole magnet 9 during the period is always changed by the rotation of the sleeve 8 and the magnet 9 in the arrow direction. The developer 11 is moved on the surface of the sleeve 8 while changing the bristle upstanding state periodically in accordance with the strength of the magnetic force of the sleeve 8 which is generated on the basis of the relative movement and the developer 11 generates frictional charge with the surface of the sleeve 8. Thus, the sufficiently frictionally charged developer 11 is adsorbed to an electrostatic latent image formed on the surface of the photosensitive body 7 to develop the electrostatic latent image.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a developing device used in an electrophotographic copying machine, etc., and particularly to a developing device for developing an electrostatic latent image on a photoreceptor to obtain a copied image of a document. The present invention relates to a developing device.

[Prior art]

FIG. 2 is a sectional view of essential parts of an electrophotographic copying machine equipped with a conventional developing device.

In the conventional developing device, the developing roll is composed of a non-magnetic sleeve 3 made of a conductive material and a magnet roll 2 which is disposed inside the non-magnetic sleeve 3 and has a plurality of magnetic poles on its surface. rotate counterclockwise,
As the magnet roll 2 rotates clockwise, the developer 5 made of only magnetic toner contained in the flopper 4 is attached onto the non-magnetic sleeve 3 by the magnetic force of the magnet roll 2, and the developer 5 is transported. conduct.

This is a device that develops an electrostatic latent image formed on a photoreceptor 1 in a developing section which is the closest portion.

[Problems with conventional technology]

In the above-mentioned developing devices, there has been a problem that the magnetic toner cannot be sufficiently triboelectrified, resulting in poor developing efficiency and failure to obtain good images.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional drawbacks.

It is an object of the present invention to provide a developing device capable of performing good development and making reproduced images stable.

[Key points of the invention]

According to the present invention, the above object is achieved by providing a rotatable multi-magnetic pole sleeve in which N and S multi-magnetic poles are arranged alternately in the circumferential direction, and a rotatable multi-magnetic pole sleeve in which N and S multi-magnetic poles are arranged in the circumferential direction. This is achieved by providing a developing device characterized by having multi-pole magnets 7) arranged alternately.

[Embodiments of the invention]

Hereinafter, two embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of essential parts of an electrophotographic copying machine equipped with a developing device of the present invention. In the figure, a developing device 6 is provided near a photoreceptor 7 that rotates clockwise, and a multi-pole sleeve 8 having alternating N and S poles is used as a sleeve.
A multi-pole magnet 9 having alternating north and south poles is used as the magnetic roll provided in the multi-pole sleeve 8. These multi-pole sleeve 8 and multi-pole magnet 9 are both supported by a support shaft (not shown).
They are pivotally supported so that they can rotate in opposite directions. Further, the hopper 10 stores a developer 11 consisting only of high-resistance magnetic toner. Further, a magnetic blade 12 is disposed on the multi-magnetic pole sleeve 8 for regulating the height of the developer 11 conveyed by the multi-magnetic pole sleeve 8 and the multi-magnetic pole magnetic throat 9 to a constant level.

Furthermore, the multi-pole sleeve 8 and the multi-pole magnet 9 are
N and S multi-pole magnetic poles are arranged alternately in the circumferential direction, and the width of each magnetic pole of the multi-pole magnet 9 is wider than the width of each magnetic pole of the multi-pole sleeve 8.

For example, in the case of nine embodiments, the area is twice as large.

In the developing device 6 of the present invention configured as described above.

The developing operation will be explained below.

The multi-pole magnet 9 rotates clockwise as described above, and at the same time the multi-pole sleeve 8 rotates counterclockwise. The interaction with each of the magnetic poles forms magnetic lines of force, and the developer 11 made of magnetic toner in the hopper is attracted onto the multi-pole sleeve 8 along the lines of magnetic force. Developer 11 attracted to multi-pole sleeve 8
is conveyed in the rotational direction of the multi-pole sleeve 8, and is regulated to a constant height by the magnetic blade 12.

Furthermore, the developer 11 regulated by the magnetic blade 12 is
The photoreceptor 7 and the multi-pole sleeve 8 are transported to the closest portion.

During this time, as shown in FIGS. 4 and 5, the lines of magnetic force formed by the multi-magnetic pole sleeve 8 and the multi-magnetic pole magnet 9 constantly change due to the rotational movement of the multi-magnetic pole sleeve 8 and the multi-magnetic pole magnet 9 in the direction of the arrow.

In this way, the change in the strength of the magnetic force on the surface of the multi-magnetic pole sleeve 8 is caused by the relative movement of the multi-magnetic pole sleeve 8 and the multi-magnetic pole magnet 9. The developer 11 moves on the surface of the multi-magnetic pole sleeve 8 while periodically changing its standing state, and the developer 11 generates frictional electrification with the surface of the multi-magnetic pole sleeve 8. The developer 11, which has been sufficiently triboelectrically charged in this manner, is attracted to the electrostatic latent image formed on the surface of the photoreceptor 7 in the developing section where the multi-pole sleeve 8 and the photoreceptor 7 face each other, and the electrostatic latent image is Develop.

Furthermore, after finishing the development, the developer 1 that did not contribute to the development
1 is returned into the hopper 10. Since the developer 11 returned into the developer 10 is undergoing a rapid change in magnetic force due to the multi-magnetic pole sleeve 8 and the multi-magnetic pole magnet 9, the developer 11 is sufficiently agitated due to this magnetic force change, and the multi-magnetic pole sleeve The developer IT is separated from the multi-pole sleeve 8.
The same developer 11 will not remain stuck forever.

By using the multi-magnetic pole sleeve 8 as the developing sleeve as described above and rotating it together with the multi-magnetic pole magnet 9 provided within the multi-magnetic pole sleeve 8.

The change time of the magnetic force on the surface of the multi-pole sleeve 8 depends on the relative rotational speed of the multi-pole sleeve 8 and the multi-pole magnet 9 and the multi-pole
It depends on the width of one pitch between the pi8 sleeve 8 and the multi-pole magnet 9, and by appropriately selecting these conditions, the magnetic toner attached to the multi-pole sleeve 8 can be sufficiently charged.

Therefore, if a sufficient amount of charge can be obtained, the multi-pole sleeve 8 may be rotated and the multi-pole magnet 9 may be fixed.

Further, in this embodiment, the magnetic pole width of the multi-pole magnet 9 is twice the magnetic pole width of the multi-pole sleeve 8.

The multi-pole sleeve and the multi-pole magnet may be configured with other magnetic pole widths, as long as the magnetic pole width of the multi-pole sleeve is narrower than the magnetic pole width of the multi-pole magnet.

〔Effect of the invention〕

As described above in detail, the developing device of the present invention rotates the multi-magnetic pole sleeve to sufficiently triboelectrically charge the developer attached to the multi-magnetic pole sleeve.

Therefore, good reproduced images can be stably obtained.

Furthermore, the developer is sufficiently stirred within the hopper due to changes in the lines of magnetic force from the multi-pole sleeve, and the developer does not stick to the multi-pole sleeve. Therefore, the magnetic toner constituting the developer flows smoothly.

Furthermore, since the magnetic toner can be sufficiently attracted onto the multi-magnetic pole sleeve, it is possible to prevent the toner from scattering from the developing device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of an electrophotographic copying machine equipped with a developing device of the present invention, FIG. 2 is a cross-sectional view of a main part of an electrophotographic copying machine equipped with a conventional developing device, and FIGS. 3 and 4 is a model distribution configuration diagram of magnetic lines of force according to the present embodiment. 7...Photoreceptor, 8...Multi-magnetic pole sleeve. 9...Multi-pole magnet, 10...Hopper, 11...Developer. 12...Magnetic blade patent Applicant: Casio Computer Co., Ltd. Same as above
Casio Electronic Industries Co., Ltd. Patent Attorney Dai
Yoshi Suga 2 Figure 1 Figure 2

Claims (3)

[Claims] (1) A rotatable multi-magnetic pole sleeve in which N and S magnetic poles are arranged alternately in the circumferential direction; A developing device comprising a magnetic pole magnet. (2) The circumferential width of each magnetic pole of the multi-pole sleeve is:
2. The developing device according to claim 1, wherein the developing device is narrower than the circumferential width of each magnetic pole of the multi-pole magnet. (3) The developing device according to claim 1 or 2, characterized in that a one-component magnetic toner is used as the developer.