JPH04255877A - Developing device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a developing device and to reduce storing space for the developing device, because the developing device itself need not be moved. CONSTITUTION:In a developing device 2 which is provided with a magnet roll obtained by arranging plural magnets 20-24 in a rotating sleeve 6 and which is constituted so that a latent image on a photosensitive body is developed by a magnetic brush formed on the sleeve 6, a driving means for normally rotating the sleeve 6 in the case of developing and reversely rotating it in the case of non-developing and a scraping member 27 for scraping developer from the sleeve 6 before the magnetic brush is formed in the case of non-developing are installed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device that performs multicolor development by supplying developers of different colors to a latent image on a photoreceptor.

0002

2. Description of the Related Art Conventional developing devices of this type are equipped with a plurality of developing devices each containing a developer of a different color, and perform multicolor development by switching the color of the developer supplied to a photoreceptor. There is.

0003

[Problems to be Solved by the Invention] However, in such a conventional developing device, the developing device itself is brought close to the photoconductor during development, and the developing device is moved so that the developer does not come into contact with the photoconductor during non-development. Since the developing color is switched by separating the developer from the photoreceptor, there are problems in that the movement mechanism of the developer is complicated and the installation space becomes large.

0004

[Means for Solving the Problems] A developing device of the present invention includes a magnet roll in which a plurality of magnets are arranged within a rotating sleeve, and develops a latent image on a photoreceptor by a magnetic brush formed on the rotating sleeve. The developing device configured as above includes a drive means for rotating the rotating sleeve in the normal direction during development and reverse rotation during non-development, and a scraping member for scraping off the developer from the top of the rotating sleeve before the magnetic brush is formed during non-development. This developing device is characterized by:

[0005] The scraping member may be a member that scrapes off excess developer from the rotating sleeve during development.

[0006]

[Operation] During non-development, the rotating sleeve rotates in reverse, and the developer is scraped off from the top of the rotating sleeve by the scraping member before the magnetic brush is formed. Therefore, since no magnetic brush is formed, the developing operation of the developing device can be stopped. Further, the scraping member can be configured to scrape off excess developer after development from the top of the rotating sleeve when the rotating sleeve rotates forward during development.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments shown in the drawings. This invention is not limited by this.

FIG. 1 is an explanatory diagram showing the main parts of a two-color development type copying machine to which an embodiment of the present invention is applied, in which 1 is a photosensitive drum, and 2 and 3 are two-component developers of different colors. (
This is a developing device that alternately develops a latent image on the photoreceptor 1 using colors (for example, red and blue). Developing devices 2 and 3 have similar configurations and perform similar operations, so developing device 2 will be described below. In the developing device 2, 4 is a magnet roll, 5a, 5b
2a is a stirring roll, and 2a is a developing device case.

FIG. 2 is an explanatory diagram of the structure of the magnet roll 3, in which 6 is a rotating sleeve, 7 and 8 are flanges attached to both ends of the rotating sleeve 6, 9 is a shaft, and 10 is a support for fixing one end of the shaft 9. It is a member. 11 and 12 are bearings provided on the shaft 9, and the flanges 7,
The rotary sleeve 6 is rotatably supported via the rotary sleeve 8 . 13
is a shaft erected on the flange 8, and is rotatably supported by a bearing 14. 15 is a motor that drives the rotating sleeve 6; 16 is a clutch that switches the rotational direction of the motor 15 to rotate the rotating sleeve 6 in forward and reverse directions; 17 is an output shaft that outputs the rotational force of the motor 15 by switching the rotational direction;
Gears 18 and 19 transmit the rotational force of the output shaft 17 to the shaft 13.

FIG. 3 is an enlarged view of the main parts of the developing device 2 shown in FIG.
6 is a holding member that holds the main developing magnet 20 and the transport magnets 21 to 24 around the shaft 9; 25 is a cutting plate that regulates the height of the magnetic brush; and 27 is a rotating sleeve 6 that rotates in the direction of arrow B. This is a scraping member that scrapes off the developer from the top of the rotating sleeve 6.

[0011] In such a configuration, when the developing device 2 performs development, the rotating sleeve 6 is connected to the motor 15 and the clutch 16.
rotates in the direction of arrow A. Thereby, the developer on the rotating sleeve 6 is cut into ears at an appropriate height by the ear cutting plate 25, and when the developer is carried by the rotating sleeve 6 to a position facing the main developing magnet, a magnetic brush is formed. Then, the latent image on the photoreceptor 1 is developed.

On the other hand, when the developing device 2 is not performing development, the rotary sleeve 6 is rotated in the direction of arrow B by the operation of the motor 15 and clutch 16, that is, in the opposite direction to that during development. As a result, the developer on the sleeve 6 is scraped off by the scraping member 26, so that almost no developer is carried to the position facing the main developing magnet 20. Therefore, no magnetic brush is formed and the latent image on the photoreceptor 1 is not developed. In this way, the developing operation of the developing device 2 is stopped.

FIGS. 4 and 5 are explanatory diagrams showing other embodiments of the present invention, and 27a is a member installed in place of the scraping member 27 in the above-mentioned embodiment, for example, a strip-shaped polyester film. It is used folded in half. The rest of the configuration is the same as the previous embodiment, so
The explanation will be omitted.

In such a configuration, when the developing device 2 performs development, the rotating sleeve 6 rotates in the direction of arrow A, as shown in FIG. As a result, a magnetic brush is formed at a position facing the main developing magnet 20, and the photoreceptor 1 is developed, as in the previous embodiment. The surplus developer after development is conveyed by the sleeve 6 as shown in FIG.

Further, when the developing device 2 is not performing development, the rotating sleeve 6 rotates in the direction of arrow B, as in the previous embodiment.
As shown in FIG. 4, the developer on the rotating sleeve 6 is
scraped off by a. Therefore, the main magnet for development 20
Since almost no developer is carried to the position facing the photoreceptor drum 1, no magnetic brush is formed and no developing operation is performed on the photoreceptor drum 1. In addition, in FIG. 4, the developer scraped off by the member 27a is accumulated at the bent portion of the member 27a, but since the member 27a is disposed at a position facing the conveying magnet 24, the developer scraped off by the member 27a is not shown in FIG. As shown, it is removed from between the members 27a by the magnetic force of the transport magnet 24. Therefore, during development, the surplus developer after development is smoothly conveyed by the rotating sleeve 6 without being scraped off by the member 27a.

[0016]

[Effects of the Invention] According to the present invention, since there is no need to move the developing device itself in order to switch the developing operation of the developing device, the configuration of the developing device is simplified and the storage space for the developing device can be reduced. can.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the main part configuration of an electrophotographic copying machine to which an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram of the configuration of a magnet roller.

FIG. 3 is an enlarged view of the main part of FIG. 1.

FIG. 4 is an explanatory diagram showing another embodiment of the invention.

FIG. 5 is an explanatory diagram illustrating the operation of the embodiment shown in FIG. 4;

[Explanation of symbols]

1 Photoreceptor drum 2,3 Developing device 4 Magnet roll 5a, 5b Stirring roll 2a Developer case 6 Rotating sleeve 15 Motor 16 Clutch 20 Main magnet for development 21, 22, 23, 24 Transport magnet 25　Scion cutting board 26 Holding member 27 Scraping member

Claims (2)

[Claims] Claim 1: A developing device comprising a magnet roll in which a plurality of magnets are disposed within a rotating sleeve, and configured to develop a latent image on a photoreceptor with a magnetic brush formed on the rotating sleeve. A developing device comprising: a drive means that rotates in the normal direction during development and reversely during non-development; and a scraping member that scrapes off the developer from the rotating sleeve before the magnetic brush is formed during non-development. 2. The developing device according to claim 1, wherein the scraping member is a member for scraping off excess developer after development from above the rotating sleeve during development.