JPH043449U

JPH043449U -

Info

Publication number: JPH043449U
Application number: JP4319590U
Authority: JP
Priority date: 1990-04-23
Filing date: 1990-04-23
Publication date: 1992-01-13

Description

[Brief explanation of drawings]

第１図は本考案の第１実施例の現像装置の断面
図、第２図は第２実施例の現像装置の断面図、第
３図ａ，ｂ，ｃは夫々第３実施例の現像ローラ近
傍の、現像時の磁石配置、非現像時の磁石配置及
び両磁石の極性を示す図式図、第４図は磁石対の
反撥力特性及び弾性部材の弾発力特性を示す曲線
図である。１…弾性現像ローラ、２…磁石、３…弾性部材
、４…固定レバー、４′…架台、５…感光体ドラ
ム、６…リング状磁石、７…外側磁石、１０…現
像ユニツト。 FIG. 1 is a cross-sectional view of a developing device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a developing device according to a second embodiment, and FIGS. 3 a, b, and c are a developing roller of a third embodiment. A schematic diagram showing the nearby magnet arrangement during development, magnet arrangement during non-development, and the polarity of both magnets, and FIG. 4 is a curve diagram showing the repulsive force characteristics of the magnet pair and the elastic force characteristics of the elastic member. DESCRIPTION OF SYMBOLS 1... Elastic developing roller, 2... Magnet, 3... Elastic member, 4... Fixed lever, 4'... Frame, 5... Photosensitive drum, 6... Ring-shaped magnet, 7... Outer magnet, 10... Developing unit.

Claims

[Scope of Claim for Utility Model Registration] (1) In a developing device that has an elastic developing roller, forms a thin layer of a one-component developer on its surface, and performs development by bringing it into pressure contact with a latent image carrier. As a means of keeping the amount of biting between the roller and the latent image carrier constant, magnetic poles of the same polarity are provided in the developing device or the developing roller and the machine frame of the main body of the device to face each other, and the repulsive force of the magnetic poles causes the developing roller and the latent image to A developing device comprising: a pair of magnets that generates an acting force that moves the carrier closer to or farther from the carrier; and an elastic member that generates an acting force that balances the acting force of the pair of magnets. (2) A claim characterized in that the above magnet pair generates a repulsive force in the direction of biting the developing roller into the latent image carrier, and this is balanced with the pressure force between the latent image carrier and the developing roller. Developing device according to item 1. (3) The developing device according to claim 2, wherein the repulsive force of the pair of magnets can be canceled or its direction can be reversed.