The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 1993
Filed:
Sep. 11, 1991
Keishi Osawa, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A developing apparatus includes a movable developer carrying member for carrying a layer of a developer containing toner particles and magnetic carrier particles to a developing zone, the toner particles and magnetic carrier particles being charged to opposite polarities; a stationary magnet disposed on a side of the developer carrying member opposite the image bearing member, the magnet forming a magnetic brush wherein the developer is contactable to the image bearing member in the developing zone; a voltage source for producing an oscillating electric field in the developing zone by application of an oscillating bias voltage to the developer carrying member; wherein the oscillating bias voltage satisfies a maximum Vu1max of a potential difference Vu1 between an image portion potential of the electrostatic image and a potential of the developer carrying member in the transfer phase of the oscillating electric field, is larger than a maximum Vr1max of a potential difference Vr1 therebetween in the back transfer phase; a time integration Iu1 of the potential difference Vu1 is larger than a time integration Ir1 of the potential difference Vr1; a maximum Vu2 max of a potential differnece Vu2 between a non-image portion potential of the electrostatic latent image and a potential of the developer carryign member in the transfer phase of the oscillating electric field, is not less than a maxiumu Vr2max of a potential difference Vr2 therebetween in the back transfer phase; and a time integration Iu2 of the potential difference Vu1 is not more than a time integration Ir2 of the potential difference Vr2.