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:
Sep. 17, 1991
Filed:
Apr. 10, 1990
Masahide Ueda, Osaka, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
An image forming apparatus for developing an electrostatic latent image formed on the surface of a photosensitive member into a visual image by the use of two-component developer consisting of toner and carrier. The apparatus is provided with a developing unit, which accommodates the developer and in which screw rollers are rotatably mounted for agitating the developer. The apparatus is further provided with an abnormality detecting system for detecting abnormalities which are liable to occur in the developing unit. The abnormality detecting system includes a toner density sensor for detecting the density of toner accommodated in the developing unit. In the normal condition, the toner density detected by the toner density sensor regularly fluctuates as the developer accommodated in the developing unit is agitated by the screw rollers. The abnormality detecting system further includes a control circuit, in which the cycle of fluctuation of the toner density is compared with that of agitation caused by the screw rollers. When both the cycles do not coincide with each other, the control circuit outputs a signal indicating that some abnormality has occurred in the apparatus.