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:
Nov. 26, 2002
Filed:
Apr. 06, 2001
Hisao Okada, Ibaraki, JP;
Hiroyuki Mabuchi, Ibaraki, JP;
Teruaki Mitsuya, Ibaraki, JP;
Shinya Kobayashi, Ibaraki, JP;
Yasuo Takuma, Ibaraki, JP;
Masayoshi Ishii, Ibaraki, JP;
Hisayoshi Kato, Ibaraki, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
In an image forming apparatus for charging a photosensitive body, changing the light exposure amount in at least three levels at exposure to light, thereby forming an electrostatic image made up of a high-potential part, a low-potential part, and an intermediate-potential part therebetween on the photosensitive body, and normally developing and inversely developing the electrostatic image using toners different in charge polarity for forming two types of toner images on the photosensitive body, a first developer used with a first toner image developing unit has electric resistance changed within 10% in the change range of applied voltage to the developer as the difference between a surface potential of the photosensitive body and a developing bias voltage.