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. 13, 1999
Filed:
Aug. 20, 1997
Takao Kumasaka, Takahagi, JP;
Nobuyoshi Hoshi, Hitachinaka, JP;
Hitcahi, Ltd., Tokyo, JP;
Abstract
A multi-color image forming apparatus is capable of decreasing the amount of ozone generation which occurs during the formation of a multi-color image. For this purpose, a charged latent image having a tri-level electric potential is formed on a positive charging photoconductor by a charging means and an exposing means. A first color toner having one of a positive polarity and a negative polarity is caused to adhere onto one of the charged latent images having the highest electric potential level at a first developing unit of the apparatus, and a second color toner having the other polarity is caused to adhere onto the other of charged latent images having the lowest electric potential at a second developing unit of the apparatus. After that, the polarity of the toner having the negative polarity is reversed using a positive corona produced by a pre-transfer charging means to unify both polarities of the two color toners, and then both toners having the unified polarity are s transferred onto a sheet of paper.