JPS61170763A - Developing device - Google Patents

Abstract

PURPOSE:To cut a magnetic force which is generated between the first and the second developing devices, to carry satisfactorily a developer, and to obtain a multicolor image of high quality by providing a diamagnetic material between magnetic pole parts of different poles opposed adjacently to each other of the first developing body and the second developing body. CONSTITUTION:Plate-shaped brass 21 serving as a diamagnetic material is provided between the first developing device 1 and the second developing device 3. This brass 21 is positioned between the fifth magnetic pole part 8e of the first developing roller 5 of the first developing device 1 and the second magnetic pole part 13b of the second developing roller 10 of the second developing device 3. A magnetic force which is generated between the fifth magnetic pole part 8e of the first developing roller 5 and the second magnetic pole part 13b of the second developing roller 10 is cut by the brass 21, the magnetic force is generated only between the respective magnetic pole parts 8a-8e, and 13a-13f of the first and the second developing rollers 5, 10, and developers 2, 4 are carried and supplied satisfactorily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a developing device, particularly for example in multicolor electronic copying machines.

[Technical background of the invention and its problems]

Recently, the use of color electronic copying machines has been progressing,9 and the technology has made remarkable progress. For example, the type of developing device shown in FIG. 4 is known as a developing device installed in this electronic copying machine. That is, in the figure, reference numeral 1 denotes a first developing device provided opposite to the photosensitive drum 14 as an image bearing member, and this first developing device IK contains a developer 2 made of toner and carrier for red copying. It is accommodated.

Further, numeral 3 denotes a second developing device provided adjacent to the lower side of the first developing device 1, and inside this second developing device 3, a developer consisting of toner and carrier for black copying is stored. 4 is accommodated.

Further, a first developing roller 5 as a first developing body is provided in the first developing device 1, and this first developing roller,
5 is a magnetic roll 6 and a rotating sleeve 7 that fits around the magnetic roll 6;
It is composed of. The magnetic roll 6 is the first to
It has a fifth magnetic pole part 8-8. Third. The fourth magnetic pole parts gm, 8a, 8d are N poles, the second . Fifth magnetic pole part Ji
b and 8a are S poles.

Further, a second developing roller 1θ as a second developing body is provided in the second developing device 3, and this second developing roller 10 also includes a magnetic roll 11 and a rotating sleeve 12 that fits around the magnetic roll 11. It is composed of. The magnetic roll 1 has first to sixth magnetic pole parts 13&~131,
The third and fifth magnetic pole parts 13m, 13c, and 13* are S poles, and the second, fourth, and sixth magnetic pole parts 13b and 13d.

131 is the north pole.

The rotating sleeve 7 of the first developing roller 5 rotates clockwise, and the rotating sleeve 12 of the second developing roller 10 rotates clockwise.
rotates counterclockwise to convey the developers 2 and 4, respectively.

Therefore, when making a red copy using the first developing device 1, the rotating sleeve 7 of the magnetic roll 5 is rotated to convey the red developer 2, and the magnetic brush is moved to the static position on the photosensitive drum 14. A red copy is obtained by sliding contact with the electrolatent image.

In addition, when making a black copy using the second developing device 3, the rotating sleeve 12 of the magnetic roll 11 is rotated counterclockwise to convey the black developer 4, and the magnetic brush touches the photosensitive drum. A black copy is obtained by slidingly contacting the electrostatic latent image on 14.

However, in the past, between the magnetic pole portions of the first developing roller 5 and the second developing roller 10 that have different polarities and are close to each other, that is, between the fifth magnetic pole portion (S) of the first developing roller 5,
A magnetic force is generated between the pole) &e and the second magnetic pole portion (N pole) 13b of the second developing roller 10, and under the influence of this, the conveyance of the developer 2.4 becomes defective9, resulting in image defects. There have been inconveniences such as the developer may fall or the developer may fall.

[Purpose of the invention]

The present invention has been made in view of the above circumstances.

The object thereof is to provide a developing device in which magnetic force is not generated between magnetic pole portions of different polarities that closely face each other in a first developing member and a second developing member.

[Summary of the invention]
In order to achieve the above-mentioned object, the present invention provides a diamagnetic material between the magnetic pole parts of the different polarities which are closely opposed to each other in the first developing body and the second developing body. This is to cut the magnetic force generated in the magnetic field.

[Embodiments of the invention]

The present invention will be described below with reference to an embodiment shown in FIGS. 1 to 3. Note that the same parts as those shown in FIG. 4 are given the same numbers and their explanations are omitted. A plate-shaped brass 21 as a diamagnetic material is provided between the first developing device 1 and the second developing device 3. This brass 21 is attached to the fifth magnetic pole portion (
S pole) 8 and the second developing roller 1 of the second developing device 3
0 and the second magnetic pole portion (N pole) 13b. As shown in FIG. 4, this brass (diamagnetic material) 21 is
When placed between the S pole of magnet 22 and the N pole of magnet 23,
It has the characteristic of cutting off the magnetic force generated between the magnets 22 and 23.

According to the above-described configuration, the first developing roller 5
The magnetic force generated between the fifth magnetic pole part (S pole) 8 and the second magnetic pole part (N pole) 13b of the second developing roller lO is cut by the brass 2, and and the respective magnetic pole portions 81 to Je, 13a of the second developing roller 5゜10.
Magnetic force is generated only between 131 and 131, and the developers 2 and 4 are transported and supplied well.

Note that the present invention is not limited to the above embodiment,
Of course, various modifications can be made within the scope of the gist.

〔Effect of the invention〕

As explained above, in the present invention, since the diamagnetic material is provided between the magnetic pole parts of the first and second developing bodies of different polarities that are closely opposed to each other, the diamagnetic material tends to be generated between the first and second developing units. The magnetic force is cut by the diamagnetic material. Therefore, each of the first and second developing bodies can transport the developer well, and
This has the effect that a high quality multicolor image can be obtained.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a schematic diagram showing a developing device, FIG. 2 is a perspective view thereof, and FIG. 3 shows characteristics of a diamagnetic material. The explanatory diagram shown in FIG. 4 is a schematic configuration diagram showing a conventional example. 14... Image bearing member (photosensitive drum), 5... I-th developing member (first developing roller), JO-... Second developing member (second developing roller), 2.4 ...Developer, 21...
・Diamagnetic material (brass). Applicant's agent Patent attorney Takeshi Suzue Red Army Figure 1

Claims (2)

[Claims] (1) First and second developing bodies are disposed adjacent to each other facing the image carrier, and the first and second developing bodies each transport developer and transfer it to the image carrier. What is claimed is: 1. A developing device comprising a plurality of supplied magnetic pole portions, characterized in that a diamagnetic material is provided between magnetic pole portions of different polarities that are closely opposed to each other in the first and second developing bodies. (2) The developing device according to claim 1, wherein the diamagnetic material is brass.