Developing apparatus
AssigneeCanon Kabushiki Kaisha
InventorsTatsuya Tada, Isami Itoh
Life of this patent
Estimating the term…
Abstract
A stationary magnet is disposed in a developing sleeve for carrying a one component magnetic developer. A regulating sleeve for regulating a layer of the developer is disposed opposed to the developing sleeve. The regulating sleeve rotates in the same direction as the developing sleeve. In the regulating sleeve, there is disposed a magnet or magnetic member cooperative with the stationary magnet to form a magnetic field in a gap between the developing sleeve and the regulating sleeve.
Claims30
A developing apparatus for developing an electrostatic latent image, comprising:
- a container for containing one component magnetic developer;
- a rotatable developer carrying member for carrying a layer of developer from said container to a developing zone for developing the electrostatic latent image, said rotatable developer carrying member having a peripheral rotation direction;
- a rotatable regulating member, disposed opposed to said developer carrying member in a regulating zone, for reducing a thickness of the layer of developer carried to the developing zone by said developer carrying member, to a predetermined thickness, said rotatable regulating member having a peripheral rotation direction that is opposite the peripheral rotation direction of said rotatable developer carrying member in the regulating zone;
- a first stationary magnet disposed in said rotatable developer carrying member and including a first magnetic pole located at the regulating zone and having a polarity;
- and
- a second stationary magnet disposed in said rotatable regulating member and including a second magnetic pole having a polarity opposite the polarity of the first magnetic pole, whereby said first and second magnets cooperate to form a magnetic field in the regulating zone;
- wherein a relation F1s.gtoreq.F2>F1 is satisfied, where F1s is a conveying force applied by said developer carrying member to a first portion of the layer of developer contacting a surface of said developer carrying member, F1 is a conveying force applied by said developer carrying member to a second portion of the layer of developer formed on the first portion of the layer of developer, and F2 is a conveying force applied by said regulating member to developer in the first and second portions of the layer of developer.
A developing apparatus for developing an electrostatic latent image, comprising:
- a container for containing one component magnetic developer;
- a rotatable developer carrying member for carrying developer from said container to a developing zone for developing the electrostatic latent image;
- a first stationary magnet disposed in said developer carrying member and comprising a first magnetic pole;
- regulating means for regulating a layer of developer to be carried to the developing zone by said developer carrying member,
- wherein said regulating means comprises a rotatable regulating member, disposed opposite said developer carrying member with a gap therebetween and in contact with developer carried on said developer carrying member at a regulating zone, said rotatable regulating member being rotatable in the same direction as said developer carrying member;
- and
- a second stationary magnet disposed in said rotatable regulating member,
- wherein said second stationary magnet includes a second magnetic pole of a polarity opposite that of the first magnetic pole of said first stationary magnet, the first and second magnetic poles cooperating to form a magnetic field in said gap;
- wherein a 50% magnetic flux density level width of the second magnetic pole is smaller than a 50% magnetic flux density level width of the first magnetic pole.
Dependencies are inferred from the claim text.