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:
Jul. 30, 1991
Filed:
Jun. 12, 1990
Fujitsu Limited, Kawasaki, JP;
Abstract
A method of detecting toner in the toner supplying unit of a developing unit wherein a toner supplying roller is caused to make a single turn, the duration of a signal indicating 'no-existence of toner' issued during this single turn period is accumulated by timer function of a control unit. When a total sum of accumulated signal timer duration is longer than a first preset time, including a constant margin added to the difference between the time required for a single turn of the toner supplying roller and the time required for passing over the toner detecting surface by a cleaning means, the 'no-existence of toner' condition is detected for the toner supplying unit. Additionally, the duration of a signal indicating 'existence of toner' is accumulated by the timer function of the control unit, and when a total sum of accumulated signal duration longer than a second preset time is required for making a single turn by the toner supplying roller, the 'existence of toner' condition is detected for the toner supplying unit.