JPH0344671A - developing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic brush developing device.

[Prior Art] A conventional developing device, known as a magnetic brush developing device (-component magnetic brush and two-component magnetic brush), has a plurality of magnetic poles inside a rotatable non-magnetic cylindrical developer conveying member. The device has a cylindrical magnetic roller magnetized to convey the developer on the developer conveying member according to the magnetic field generated by the magnetic roller, and the magnetic roller has a sintered ferrite magnet. It was used. In addition, the developer agitation/supply means in the developing device include rotating metal cylindrical members, spiral coil-shaped members arranged around the cylindrical member, and rotating members with stirring blades. It was something.

[Problem to be Solved by the Invention] However, in the above-mentioned conventional technology, when the developer is agitated by the rotation of the developer agitation/supply means, the developer in the development device is not charged enough for development. , Also, developer stirring/
Due to the rotation of the supply means, the developer is pressed against the wall surface of the developing device, causing stagnation of the developer, which not only causes the developer to not be consumed effectively, but also causes aggregation of the developer, resulting in , which had an adverse effect on the development characteristics.

The present invention is intended to solve these problems, and its purpose is to effectively consume the developer in the developing device, prevent agglomeration of the developer in the developing device, and reduce the charging of the developer. An object of the present invention is to provide a developing device capable of performing sufficiently stable development.

[Means for Solving the Problems] The developing device of the present invention includes a cylindrical magnetic roller configured with a rare earth magnet magnetized with a plurality of magnetic poles inside a non-magnetic cylindrical developer conveying member. In a developing device that has a magnetic roller and holds the developer on a developer transporting member according to a magnetic field, and transports the developer by rotating at least one of the developer transporting member or the magnetic roller. The apparatus is characterized in that a magnetic member is used as a developer stirring/supplying means within the apparatus.

[Function] According to the above structure of the present invention, by disposing the developer stirring/supplying means using a magnetic member in the developing device, the magnetic developer can be stirred and supplied using the magnetic member. Since the developer is magnetically attracted to the developer stirring and supplying means and forms a magnetic brush on the developer stirring and supplying means, unlike the conventional developer stirring and supplying means, the developer is pressed against the wall surface of the developing device and adheres to the wall surface of the developing device. The developer can be completely supplied to the vicinity of the developer conveying member without causing any stagnation. By constructing the developer stirring/supplying means with a magnetic material such as ferrite, when the developer approaches a magnetic roller composed of rare earth magnets, the developer is composed of rare earth magnets that have higher magnetization and magnetic flux density than ferrite magnets. The developer is moved onto the developer transporting member containing the magnetic roller, and is transported to the developing position without being held by the developer stirring/supplying means.

Hereinafter, the present invention will be explained in detail with reference to Examples.

[Embodiment] FIG. 1 is a cross-sectional schematic diagram of a developing device in an embodiment of the present invention.

The latent image carrier 1 has a photoconductive layer 3 coated on a conductive support portion 2 . Charger 4 charges photosensitive layer 3
After being charged to a predetermined potential, the light emitted from the light fi5 such as a laser is scanned using a rotating polygon mirror (not shown), and an image is formed on the photosensitive layer 3 by the imaging optical system 6. An electrostatic latent image was formed on the latent image carrier 1 by obtaining a potential contrast. On the other hand, the developing device uses a developer 7 which is an image forming body.
is charged and held on a non-magnetic, cylindrical developer transport member 8, and transported, and the electrostatic charge of the latent image carrier L is removed at a development gap portion where the latent image carrier 1 and the developer transport member 8 are close to each other. The electrostatic latent image is developed with the developer 7 according to the latent image and the bias voltage applied by the developing bias applying means 9. The developing device agitates the developer 7 supplied inside the container 10 by a developer stirring/supplying means 14 composed of a ferrite magnet, and then supplies the developer to a developer conveying member 8 and transporting amount regulating member 1.
1 regulates the appropriate amount, holds it on the developer conveying member 8 by magnetic force, and conveys it to the developing position, and the developer conveying member 8
A magnetic roller 12 made of a cylindrical rare earth magnet is disposed inside with a gap interposed therebetween. By using a magnet for the developer agitation/supply means 14, the magnetic developer 7 can adhere to the developer agitation/supply means 14 and move as the developer agitation/supply means 14 rotates. .

In addition, since the developer 7 is attracted by magnetic force, the developer 7 is pressed against the wall of the container and adheres to the wall of the container, which was the case with conventional developer stirring/supplying means. Therefore, the phenomenon that the developer 7 was not consumed and the developer stagnation was not observed. By constructing the developer stirring/supplying means 14 with a ferrite magnet, which has inferior magnetic force than the magnetic roller 12 composed of a rare earth magnet in the developer conveying member 8, the developer 7 is transferred to the developer conveying member 8. When approached, the developer 7 moves from the developer agitation/supply means 14 onto the developer transport member 8, and the developer 7 is smoothly transferred to the developer transport member 8 without continuing to be held in the developer agitation/supply means 14. Supplied on 8. In addition, in Figure 1,
The arrows indicate the direction of rotation of each member, but are not intended to limit the invention.

FIG. 2 is a schematic diagram of the developer stirring/supplying means 14 in an embodiment of the present invention, in which a magnet member 15 is arranged on a cylindrical member. A magnetic brush of the developer 7 is formed on the magnet member 15 and presses the developer 7 against the wall of the container, so that the developer adheres to the wall of the container, so that the developer 7 is not consumed and the development is prevented. The phenomenon of agent retention does not occur. Note that in FIG. 2, arrows indicate the rotation direction of members, but this does not limit the present invention.

FIG. 3 is a schematic diagram of the developer stirring/supplying means 14 in another embodiment of the present invention. Magnet member 15 on the cylindrical member
is arranged. A magnetic brush of the developer 7 is formed on the magnet member 15 and presses the developer 7 against the wall surface of the container, and the developer adheres to the wall surface of the container.
is not consumed, and the phenomenon of developer stagnation does not occur. In addition, although the arrow in FIG. 3 indicates the rotation direction of the member, it does not limit the present invention.

As the developer used in the present invention, all developers known as a -component magnetic brush developer and a two-component magnetic brush developer are applicable. Further, as the developer conveying member used in the present invention, any non-magnetic and conductive member typified by stainless steel, aluminum, and brass can be used. Furthermore, the rare earth magnet materials used in the present invention include 14 rare earth elements ranging from Ce with an atomic number of 58 to LU with an atomic number of 71, especially Nd, Pr, and S.
At least one of m is 3di represented by Fe, Ni, and Co! ! Those to which a transfer metal or the like is added can be used.

More detailed examples will be shown below.

Example 1 In a developing device as shown in FIG. 1, a developer conveying member 8 with an outer diameter of 20 mm is used, and a magnetic roller 12 disposed inside the member is made of samarium cobalt-based material with an outer diameter of 18 mm and a wall thickness of 2 mm. As shown in FIG. 2, a developer stirring/supplying means 14 made of injection-molded magnets is disposed near the developer conveying member 8, as shown in FIG. The developer was magnetically attracted by the developer stirring/supplying means 14 and supplied to the developer transporting member 8 .

When a one-component magnetic developer was placed in the container 10 and images were formed on 10,000 sheets of recording paper with the above configuration, no segregation of the developer was observed within the container 10, and no developer was observed to adhere to the wall surface. I couldn't. The stirring state of the developer was also good, and no aggregation of the developer was observed, and stable image formation was possible with no problems in both recording density and fine line reproducibility.

Comparative Example Image formation was carried out in the same manner as in Example 1, except that a stainless steel member was used as the developer stirring and supplying means.

When a single-component non-magnetic toner was placed in the container 10 and images were formed on 10,000 sheets of recording paper with the above configuration, the container 10
Segregation of developer was observed within the wall, and developer was observed to be stuck to the wall surface. The agitation condition of the developer was also poor, and agglomeration of the developer was observed, resulting in changes in recording density and thin line reproducibility, making it impossible to form stable images.

Example 2 Image formation was carried out in the same manner as in Example 1 using the developing device as shown in FIG. 1, except that the developer stirring/supplying means 14 had the shape as shown in FIG. As a result, the developer was able to be stably supplied to the developer transport member.

When a one-component magnetic developer was placed in the container 10 and images were formed on 10,000 sheets of recording paper with the above configuration, no segregation of the developer was observed within the container 10, and no developer was observed to adhere to the wall surface. I couldn't. The stirring state of the developer was also good, and no aggregation of the developer was observed, and stable image formation was possible with no problems in both recording density and fine line reproducibility.

Example 3 In a developing device as shown in FIG. 1, a developer conveying member 8 having an outer diameter of 20 mm is used, and a magnetic roller 12 disposed inside the member is replaced with a praseodymium-based roller having an outer diameter of 18 mm and a wall thickness of 2 mm. When a developer stirring/supplying means 14 made of a cast magnet and made of a ferrite magnet is disposed close to the developer conveying member 8 as shown in FIG. 2, the magnetic developer is
The developer was magnetically attracted by the developer stirring/supplying means 14 and supplied to the developer transporting member 8 .

When a one-component magnetic developer was placed in the container 10 and images were formed on 50,000 sheets of recording paper with the above configuration, no segregation of the developer was observed within the container 10, and no developer was observed to adhere to the wall surface. I couldn't. The stirring state of the developer was also good, and no aggregation of the developer was observed, and stable image formation was possible with no problems in both recording density and fine line reproducibility.

Example 4 In a developing device as shown in FIG. 1, a developer conveying member 8 with an outer diameter of 20 mm is used, and a magnetic roller 12 disposed inside the member is replaced with a neodymium roller 12 with an outer diameter of 18 mm and a wall thickness of 2 mm. When a developer stirring/supplying means 14 made of a sintered magnet and made of a ferrite magnet is disposed close to the developer conveying member 8 as shown in FIG. The developer was magnetically attracted by the stirring/supplying means 14 and supplied to the developer conveying member 8 .

When a one-component magnetic developer was placed in the container 10 and images were formed on 50,000 sheets of recording paper with the above configuration, no segregation of the developer was observed in the container 10, and no developer was observed to adhere to the wall surface. I couldn't. The stirring state of the developer was also good, and no aggregation of the developer was observed, and stable image formation was possible with no problems in both recording density and fine line reproducibility.

Although the embodiments have been described above, the present invention can be applied not only to the above embodiments but also to a wide range of developing devices such as electrophotography.
It is particularly effective when applied to printers, copiers, facsimile machines, and displays.

[Effects of the Invention] As described above, a cylindrical magnetic roller made of a rare earth magnet magnetized with a plurality of magnetic poles is provided inside the non-magnetic cylindrical developer conveying member, and In a developing device that transports the developer on the developer transporting member according to a magnetic field generated by a magnetic roller, the developer in the developing device is effectively used by using a magnetic member as a developer stirring means in the developing device. Since the developer is consumed, there is no aggregation of the developer in the developing device, and the developer is sufficiently charged, it is possible to provide a developing device that can stably produce high image quality.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional schematic diagram of a developing device in an embodiment of the present invention. FIG. 2 is a schematic diagram of a developer stirring/supplying means in an embodiment of the present invention. FIG. 3 is a schematic diagram of a developer stirring/supplying means in another embodiment of the present invention. Latent image carrier Conductive support Photosensitive layer Charger Light source Imaging optical system Developer Developer conveyance member Development bias application means Container conveyance amount regulating member Magnetic roller Developer stirring/supplying means Magnet member

Claims (1)

[Claims] (1) A cylindrical magnetic roller made of a rare earth magnet magnetized with a plurality of magnetic poles is provided inside the non-magnetic cylindrical developer conveying member, and the magnetic field generated by the magnetic roller is Therefore, in a developing device that holds the developer on the developer transporting member and transports the developer by rotating at least one of the developer transporting member or the magnetic roller, the developer stirring/supplying means in the developing device is A developing device characterized by using a magnetic member.