JPS61201279A - Magnetic brush developing device - Google Patents

Abstract

PURPOSE:To rub a developer layer on a developing sleeve against the surface of an image carrier during development ad to separate it from the image carrier surface when the development is not carried out by using a magnetic body as a nap cutting plate and rotating and displacing a magnet body to a position where one magnetic pole faces the nap cutting plate when the development is completed. CONSTITUTION:When the developing sleeve 3 rotates as shown by an arrow, the developer in a developer reservoir 6 attracted to the developing sleeve 3 with the magnetic force of magnetic poles 44 and 45 of the magnet body 4 passes through the gap between the nap cutting plate 5 and developing sleeve 3 to nearly the same thickness to form the developer layer, which is raised in a development area with lines of magnetic force from a magnetic pole 41 and rubbed against the surface of the image carrier to develop the latent image. When the development is completed, the magnet body 4 is rotated and displaced so that a magnet pole 46 faces the nap cutting plate 5. Consequently, an intense magnetic field which inhibits a developer from moving owing to the rotation of the developing sleeve 3 is established between the nap cutting plate 5 and magnetic pole 46, and almost no developer layer is formed on the surface of the developing sleeve 3 which passes by the nap cutting plate 5, so that the developer layer on the developing sleeve 3 does not contact the surface of the image carrier 1.

Description

[Detailed Description of the Invention] (Industrial Application Field) 2. The present invention relates to a magnetic brush developing device, and is particularly suitable for multicolor recording devices such as 2' color electrophotographic copying machines and full color copying machines. Magnetic brush developing device used
J・′1′,・・(Prior art),,2,,,,.

, a multi-color recording device has a multiple developing device disposed along the moving path of the image carrier surface, and forms an electrostatic latent image or a magnetic partial image on the image carrier surface IK, 1!li! Most of the products are developed using a different developing device each time.
A so-called magnetic brush development device is used to form three layers of p% image marks 1, and to develop the latent image by rubbing the Keyaki support ring with the developer layer.
, often used, raB-'<. In the above-mentioned multicolor recording device, the small surface of the image carrier on which the latent image is formed is developed by the device.

The developed surface passes through the developing device and is brought to the latent image forming area again, or is brought to the transfer area and cooled. ) Therefore, when a magnetic brush developing device is used, when the latent image surface or the image surface of the image carrier simply passes through,
There is a condition where the developing device does not develop. In other words, do not leave any impressions on the development of the town.

That is, it is necessary to maintain a state in which the developer layer on the developing sleeve does not come into contact with the surface of the image carrier. ,
As a multicolor recording device using a magnetic brush developing device,
Of the multiple developing devices, the one that performs development is the first.
ll+1
- A copying device in which the first abutment roller is brought close to contact the photoreceptor drum, which is an image bearing member, and those not performing development are separated from the photoreceptor drum is USP;
It is known from the publication No. 3.854.449, and it is
゛: Force that separates and brings multiple developing devices into contact with the photoreceptor drum side.

The developing device that performs development is brought close to the position where the magnetic brush on the developing sleeve (developer sleeve) rubs the surface of the photoreceptor drum, and the developing device that performs development is forced so that the magnetic brush does not come into contact with the photoreceptor drum. The copying device spaced apart at the U
This is known from Publication SP 3,970,042. A recording device in which such a developing device is moved is
The mechanism for moving it is complicated, the recording device is larger,
In addition to being expensive, it also has the disadvantage that it is difficult to maintain accuracy during development.

As a way to keep the magnetic brush in contact or out of contact without moving the developing device, it is possible to control the developer layer on the developing sleeve. When developing is carried out by making the cutting plate that regulates the butt movable, the position of the cutting plate should be adjusted so that it comes into contact with the surface of the image carrier, and a magnetic brush is used as a return device to perform the development. In this case, the position of the cutting board can be changed by developing. Although this method does not make the recording device larger, there is a high risk that the movement of the cutting board will not be carried out smoothly. There is a drawback that it is difficult to maintain accuracy during i-time and door development. ゛ [Purpose of the Invention] □ The present invention has been made in order to provide a magnetic brush developing device that eliminates the above-mentioned drawbacks. In addition, a magnetic brush is formed on the developing sleeve that rubs the surface of the image carrier during development without moving the developing device or the cutting plate, and during non-development, it moves the developer layer on the developing sleeve onto the image carrier. It is also an object of the present invention to provide a magnetic brush developing device which can be made without contact and is suitably used in a multi-color recording device. The present invention provides at least ``a magnetic body in which the developing sleeve nib rotates once during development, and a plurality of magnetic poles are arranged in the circumferential direction inside.
The magnetic pole is fixed with its magnetic pole facing the developing area, and the developer layer that moves and moves on the developing sleeve as it rotates and extends on the developing sleeve is placed on the surface of the developing sleeve. Magnetic brush development in which a developer layer placed between the magnetic ridges of the magnet bodies 6 facing each other and regulated and restrained by the plate cut earlier, and regulated by the layer 1, rubs against the surface of the image carrier in the development area. In the apparatus, a magnetic material is used for cutting the ears, and the magnet body is rotated to a position where one pole faces the ear cutting plate at the end of development. This configuration achieves the above purpose.゛ □ ゛
□ ・ ::・ ′ [Example]
, Hereinafter, the present invention will be explained with reference to illustrated examples.・′□ □・
115th! iI is a partial sectional view of a recording device showing an example of the developing device of the present invention, and FIG. 2 is a partially enlarged view of FIG.・Shiya
A drum-shaped image carrier on which an electrostatic latent image or a magnetic latent image is formed by a powerful known latent image forming device.The formed latent image is developed into a toner image by a developing device, and the toner image is If it is shown in the figure, it is transferred onto recording paper or the like by a known transfer device and then affixed.

□The developing device 2 is equipped with a developing sleeve □3 made of a non-magnetic material such as aluminium or stainless steel, which rotates in the direction of the arrow at an opening facing the image carrier 1. is provided with a magnet body 4 having a number of magnetic poles 41 to 46 arranged in the circumferential direction, and furthermore, a developing sleeve □ is provided on the exit side of the opening where the developing sleeve 3 turns in the direction of the arrow.
- Opposing the surface of the blade 30, there is provided an ear cutting plate 5 made of a magnetic material such as tweezers, magnetic stainless steel, or iron rod.

When the latent image on the image carrier 1 is developed using this developing scissors lid design, the table moves the □magnet 4 to the position where the magnetic pole 41 is closest to the developing area, that is, the image carrier 1, as shown in FIG. The magnetic poles 45 and 46 are rotated to a position where they face the ear cutting plate 5. When the developing sleeve 3 rotates in the direction of the arrow in the state shown in FIG. 46. It is held on the developing image sleeve 3 by the magnetic force of 41 to 43, moves in the same direction as the developing sleeve rotates 30 times, and returns to the developer reservoir and 6, but in the middle of the development area In step 5, the developer layer stands up due to the lines of magnetic force from the magnetic pole 41, and develops the latent image as it rubs against the carrier surface.
When the latent image on the image carrier 1 passes through the development area and the development is completed, the magnet body 4 is rotated about 20 degrees in the direction of the arrow as shown in FIG. Bring it to a position facing the cutting board 5. As a result, a strong magnetic field is formed between the ear cutting plate 5 and the magnetic pole 460゛□ of the magnet body 4, which prevents the developer from moving as the developing sleeve 3 rotates. On the surface of the developing sleeve 3 passing through the positions ν, 1, ζ, ′...5, there is almost no image-side layer, or even if there is, it is very thin.
The developer layer on the developing sleeve 3 does not come into contact with the surface of the image carrier 1. In the example shown in FIG. 2, the magnetic body is rotated 40 times to force the middle of the magnetic poles 41 and 42 to face each other in the developing area.
is parallel to the surface of the image carrier 10, so that the layer of developer on the developing sleeve 3 is more securely prevented from contacting the surface of the image carrier 10. Therefore, from now on, the latent image or the developing surface of the image carrier 1 passes through the developing device 2. However, the latent image 2 that passes through this developing device 2,
j When the surface is developed, it is inevitable that the developed surface will be disturbed.

In the developing device of the present invention described above, the developing sleeve 3
may continue to rotate even after the end of development, or may stop rotating after the strong developer layer contacts the image carrier 1 and reaches the current level. In addition, the developer is
1, τ, using magnetic toner, or a developer using toner and a magnetic carrier.・J゛9ノ(17,""'ll1, ゛-A developing device using a mechanical component ``developer'' supplied with magnetic toner from a cartridge 7 is shown.

〔Effect of the invention〕

As described above, the magnetic brush developing device of the present invention allows the developer layer on the developing sleeve to rub against the surface of the image carrier during development, without moving the developing device or the cutting board, and during non-development, the image bearing surface is rubbed. Since it can be in a state where it does not come into contact with the surface of the carrier, it is suitably used in two-color electrophotographic copying machines, multicolor or full-color electrophotographic copying machines, electrophotographic color printers, electrostatic color printers, and the like. However, even when the magnetic brush developing device of the present invention is used in a monochrome recording device, toner consumption can be reduced and the burden on the image carrier cleaning device can be reduced.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a recording device showing an example of the developing device of the present invention, and FIG. 2 is a partially enlarged view of FIG. 1 showing a state when development is stopped. 1... Image carrier, 2... Developing device, 3...
...Developing sleeve, 4...Magnet,...
(8) , Pa \, ゛4 bill ~ ゛16...magnetic pole, 5...ear cutting board,
'6...Developer reservoir 1. 7...Toner supply cartridge. Patent applicant Konishiroku Photo Industry Co., Ltd.
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Claims (2)

[Claims] (1) At least during development, the developing sleeve rotates, and a magnet body with multiple magnetic poles arranged in the circumferential direction is fixed with one magnetic pole facing the developing area, and as the developing sleeve rotates, the developing sleeve rotates. The thickness of the moving developer layer is regulated by a cutting plate provided between the magnetic poles of the magnet body facing the developing sleeve surface, and the developer layer with the regulated thickness is regulated in the developing area. In a magnetic brush developing device that rubs the surface of an image carrier,
A magnetic brush developing device characterized in that a magnetic material is used for the ear cutting plate, and the magnet body is rotated to a position where one magnetic pole faces the ear cutting plate at the end of development. (2) The magnetic brush developing device according to claim 1, wherein the rotational displacement of the magnet body at the end of development causes the magnetic poles to face the development area.