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. 19, 1997
Filed:
Oct. 03, 1995
Fumihiro Sasaki, Fuji, JP;
Satoshi Mochizuki, Numazu, JP;
Hidefumi Gohhara, Numazu, JP;
Megumi Sakakura, Numazu, JP;
Seiji Oka, Yokohama, JP;
Hajime Oyama, Ichikawa, JP;
Kiyonori Tsuda, Tokyo, JP;
Yasushi Akiba, Chiba, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
In an image forming apparatus, a developing device has a developing sleeve accommodating a magnet roller therein, and a doctor for regulating the amount of developer to be conveyed to a developing position. When the developing sleeve is rotated, the part of the doctor shaved off by the doctor from the sleeve is moved in a developer storing section to a toner replenishing opening formed in a toner storing section. Then, this part of the developer is returned to the doctor along the surface of the sleeve via the toner replenishing opening. The developer consists of a first developer containing a first carrier and deposited in a layer on the surface of the sleeve, and a second developer containing a second carrier different from the first carrier and stored in the developer storing section in such a manner as to contact the first developer deposited on the sleeve. The first carrier has a higher charging ability than the second carrier. The device does not need a toner replenishing mechanism or a toner concentration sensor and has, therefore, a miniature and inexpensive construction. In addition, the device is applicable even to a high-speed image forming apparatus.