JPH04255876A - 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:As to the developing device 2 which is provided with a magnet roller 4 obtained by arranging plural magnets in a rotating sleeve 7 and which is constituted so that a latent image on a photosensitive body is developed by a magnetic brush formed on the sleeve 7, a magnet holding body which holds the magnet in the sleeve 7 and is rotatably supported coaxially with the shaft 10 of the sleeve, a bristle cutting plate which regulates the height of the bristle of the magnetic brush and a driving means 26 for rotating the magnet holding body are installed. When development is not performed, the magnet holding body is rotated so as to make one magnetic pole of the magnet in the sleeve 7 opposed to the bristle cutting plate.

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 developer is not brought into contact with the photoconductor during non-development. Since the developing color is switched by separating the developing device itself from the photoconductor, there is a problem that the moving mechanism of the developing device is complicated and the installation space becomes large.

[0004] The present invention was made in consideration of the above circumstances, and it is possible to change the developed color without moving the developing device relative to the photoreceptor, and the configuration is simple and the installation space is reduced. The present invention provides a developing device that is capable of

[0005]

[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. In the developing device configured as above, a magnet holder that holds the magnet in the rotating sleeve and is rotatably supported coaxially with the axis of the sleeve, an ear cutting plate that regulates the height of the ears of the magnetic brush, and a magnet. The developing device is equipped with a drive means for rotating the holder, and when not in development, the magnet holder is rotated so that one magnetic pole of the magnet in the rotating sleeve is opposed to the ear cutting plate.

[0006]

[Operation] When not developing, the magnet holder rotates and one magnetic pole of the magnet in the rotating sleeve faces the ear cutting plate, so the developer that stands on the ears on the rotating sleeve is regulated by the ear cutting plate. Ru. Therefore, even if a magnetic brush is formed by the developer regulated by the spike cutting plate in the spike state, the height of the spike is sufficiently lower than during development, so the latent image on the photoreceptor will not be developed. . Therefore,
The developing operation can be stopped without moving the developing device.

[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 of the main part of a copying machine that performs two-color development to which an embodiment of the present invention is applied. In FIG. 1, 1 is a photoreceptor drum, and 2 and 3 are developing devices that develop an electrostatic latent image on the photoreceptor 1 using two-component developers of different colors (for example, blue and red). 3, the developing operation is performed alternately. In this embodiment, the developing units 2 and 3 have the same configuration and operate in the same manner, so the developing unit 2 will be described below.

In FIG. 1, 4 is a magnet roll;
6 is a stirring roll, and 2a is a developing device case. FIG. 2 is a configuration explanatory diagram showing the configuration of the magnet roll 4, and FIG.
FIG. In these figures, 7 is a rotating sleeve, 8 and 9 are flanges attached to both ends of the rotating sleeve, and 10 is supported by a bearing 11 provided on flange 8 and a bearing provided on flange 9, and is rotatable by bearing 13. 14 is a main magnet for development, 15 to 18 are transport magnets, and 19 is a holding member that holds the magnets 14 to 18 around the shaft 10. A shaft 20 stands upright from the flange 8 and is rotatably supported by a bearing 21. 22 is a motor that drives the rotating sleeve 7; 23 is an output shaft of the motor 22;
24 is a gear fixed to the output shaft 23, 25 is the shaft 2
This gear is fixed at 0 and meshes with the gear 24. 26 is a solenoid that rotates the shaft 10, 27 is a shaft 1
0 and the solenoid 26.

The broken line shown in FIG. 3 shows the outline of the magnetic force distribution on the surface of the rotating sleeve 7. The magnetic force of the main developing magnet 14 is 800 Gauss (N pole), and the magnetic force of the transport magnet 15 is 700 Gauss.
Gauss (S pole), the magnetic force of the transport magnet 16 is 600 Gauss (
N pole), the magnetic force of the transport magnet 17 is 700 Gauss (S pole),
The magnetic force of the transport magnet 18 is 600 Gauss (S pole).

FIG. 4 is an enlarged view of the main part of FIG. 1, and reference numeral 28 denotes a cutting plate for regulating the height of the ears of the magnetic brush. When the developing device 2 develops the latent image on the photoreceptor 1, the motor 22
As a result, the sleeve 7 rotates in the direction of arrow A as shown in FIG. At this time, the solenoid 26 is not energized and the shaft 10 is maintained in the rotational position shown in FIG. In other words, none of the magnets in the rotating sleeve 7 face the ear cutting plate 27. The two-component developer conveyed by the rotating sleeve 7 is cut (regulated) at the part of the cutter plate 27 in such a manner that the two-component developer does not stand up. and,
When the two-component developer regulated by the cutting plate 27 is conveyed by the rotating sleeve 7 to a position facing the main developing magnet 14, a magnetic brush of a height sufficient to sufficiently develop the latent image on the photoreceptor 1 is moved. Form. Therefore, development is performed in the state shown in FIG.

FIG. 5 is an explanatory diagram showing the state of the developing device 2 during non-developing. In this case, the sleeve 7 rotates in the direction of arrow A, and the solenoid 26 is energized, causing the shaft 10 to rotate.
is maintained at a position rotated by a predetermined angle clockwise. As a result, the magnet 1 inside the rotating sleeve is attached to the ear cutting plate 28.
The magnetic poles of 5 face each other. Therefore, the two-component developer conveyed by the rotating sleeve 7 forms spikes at the spike cutting plate 28 . When the two-component developer in a state of standing spikes is regulated by the spike cutting plate 28, even if the two-component developer moves on the rotating sleeve 7 to a position facing the main developing magnet 14, the two-component developer remains at that position. Since the magnetic brush that is formed does not have a sufficient height, the latent image on the photoreceptor 1 cannot be developed. Therefore, as shown in FIG. 5, by rotating the shaft 10 by the solenoid 26, the developing operation of the developing device 2 is stopped.

In this way, when the developing device 2 shown in FIG. Two-color development is performed.

[0014]

[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 a configuration explanatory diagram showing the main parts of an electrophotographic copying machine to which an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram of the main part configuration of a developing device.

FIG. 3 is a sectional view taken along the line XX in FIG. 2;

FIG. 4 is an explanatory diagram illustrating the state of the developing unit during the developing operation.

FIG. 5 is a diagram corresponding to FIG. 4 illustrating the state of the developing device during non-developing operation.

[Explanation of symbols]

2 Developing device 7 Rotating sleeve 10 Shaft 22 Motor 14 Main developing magnets 15, 16, 17, 18 Transport magnet 19
Holding member 26 solenoid

Claims (1)

[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 photoconductor with a magnetic brush formed on the rotating sleeve. a magnet holder that holds the magnet and is rotatably supported coaxially with the axis of the sleeve, and a cutting plate that regulates the height of the ears of the magnetic brush;
What is claimed is: 1. A developing device comprising a driving means for rotating a magnet holder, and during non-developing, the magnet holder is rotated so that one magnetic pole of a magnet in a rotating sleeve is opposed to an ear cutting plate.