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:
Apr. 18, 1989
Filed:
Oct. 15, 1982
Nobuyoshi Hoshi, Hitachi, JP;
Masayasu Anzai, Hitachi, JP;
Isamu Komatsu, Takahagi, JP;
Susumu Akimaru, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A toner of a first color incorporated into a development appartaus for second color is charged to a polarity opposite to a polarity of a charge of an electrostatic latent image for the second color by a frictional action with a toner in the development apparatus for the second color. The toner of the first color incorporated into the second development apparatus is caused to adhere to a charge-non-released region of a drum, whereby accumulation of the first toner in the second color development apparatus is prevented. The first and second toners are electrostatically transferred onto a paper by a bias electric field having a polarity opposite to that of the toner images, whereby at reversal development of the second color, the toner of the first color adhering to the charge-non-released region is prevented from being transferred onto the paper. Further, the toner of the first color, incorporated in the second development apparatus, changed reversly in its polarity, or reduced to about zero in the charge quantity can be removed by electrical and mechanical removal means provided in the second development apparatus.