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. 04, 1997
Filed:
May. 11, 1995
Takahiro Tamiya, Tokyo, JP;
Nobuo Iwata, Sagamihara, JP;
Tsuyoshi Deki, Koshigaya, JP;
Takeshi Motohashi, Kawasaki, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
In an image forming apparatus of the type sequentially forming powder images of different colors on an image carrier, and sequentially transferring them to an acceptor one above the other (primary transfer), an image transfer method is disclosed which prevents transfer dust from being transferred to the acceptor at the time of the primary transfer. During the primary transfer, a bias potential V.sub.1 is applied to one of two conductors located at an upstream side. The potential V.sub.1 has the same polarity as the charged powder carried on the image carrier. A potential V.sub.2 is applied to the other conductor at a downstream side and provided with a polarity opposite to the polarity of the charged powder. Every time the primary transfer is repeated, the potentials V.sub.l and V.sub.2 are respectively sequentially shifted toward the polarity of the powder and toward the polarity opposite to the polarity of the powder.