US 9,069,277 B2Granted

Image forming apparatus including a controller configured to switch a state of developing roller between a stopped state and a rotating state

AssigneeBrother Kogyo Kabushiki Kaisha

InventorsYasuhiro Suzuki, Yoshiteru Hattori

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Abstract

An image forming apparatus may include controls for changing a state of a developing roller from a stopped state to a rotating state. The change in state may be used to avoid deterioration of toner and/or a surface of the developing roller. Changes in state may occur at various times including at a timing corresponding to an outside of an image formation area, a timing corresponding to an inside of an image formation area and the like. In one arrangement, a first developing roller may continue to rotate (e.g., during monochrome printing), while one or more other developing rollers are switched between a stopped state and a rotating state. Alternatively or additionally, a roller which is caused to change states may remain stopped between the timing corresponding to a rear end of an image formation area and a timing corresponding to a front end of an immediately subsequent image formation area.

Claims17

Dependent claims

An image forming apparatus, comprising:

a first photosensitive member corresponding to a first developer;
a second photosensitive member corresponding to a second developer;
a first exposure device configured to expose the first photosensitive member;
a second exposure device configured to expose the second photosensitive member;
an endless belt disposed such that the endless belt contacts the first photosensitive member and the second photosensitive member;
a first developing roller configured to rotate and supply the first developer to a first contact position where the first photosensitive member contacts the first developer;
a second developing roller configured to rotate and supply the second developer to a second contact position where the second photosensitive member contacts the second developer;
and
a controller configured to:
cause a first switch of the second developing roller, during a continuous rotation of the first developing roller, from a first state where the second developing roller stops with the second photosensitive member contacting the second developer to a second state where the second developing roller rotates with the second photosensitive member contacting the second developer, and
cause a second switch of the second developing roller, during the continuous rotation of the first developing roller, from the second state to the first state,
such that both of the first switch and the second switch occur in a period between a timing corresponding to a rear end of a first image formation area and a timing corresponding to a front end of a second image formation area immediately subsequent to the first image formation area, and
such that the second developing roller rotates less than 360° in the second state.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/338,758Filed 28 Dec 2011
Priority: JP 2010-29322228 Dec 2010
Published: US 2012/0163871 A128 Jun 2012
Granted: 30 Jun 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G03G 15/0136
For transferring a pattern to a second base: transfer member separable from recording member or vice versa, mode switching
G03G 15/0189
Using more than one reusable electrographic recording member, e.g. one for every monocolour image: primary transfer to an intermediate transfer belt
G03G 2215/0103
For producing multicoloured copies: plural electrographic recording members
G03G 2215/0119
Plural electrographic recording members: linear arrangement adjacent plural transfer points