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:
Aug. 07, 1990
Filed:
May. 17, 1989
Hitachi, Ltd., Tokyo, JP;
Hitachi Koki Co., Ltd., Tokyo, JP;
Abstract
A developing device is of non-contact development type in which a toner is jumped to a photoconductor to develop a latent image on the photoconductor. The developing device is controlled in height of a developer-agent layer on a developer roll, and sets a developing gap between the photoconductor and the developer roll in such a manner that a driving electric field required for jumping of the toner can be maintained at the air gap between the photoconductor and a developer-agent layer on the developer roll and developing bias voltage can be brought to a value lower than charged electric potential of the photo-conductor. By setting the developing bias voltage to the valve lower than the charged electric potential of the photoconductor, jumping of additional or unnecessary toner is restricted so that contamination of an image and a recording sheet can be prevented. Further, a multi-color recording apparatus having this developing device prevents toner developer agents different in color from being brought into contact with each other to form a clear multi-color image without mixing in color and contamination.