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. 27, 1993
Filed:
Sep. 27, 1991
Susumu Imakawa, Yokohama, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A focusing error detection apparatus for detecting a focusing error of a converging light beam on a surface of a recording medium in an image forming system. The apparatus includes a pair of mutually opposed first and second knife edges placed adjacent to the recording medium, a photodetector for outputting a signal indicative of a quantity of light received by the photodetector, a differentiation circuit for outputting a signal proportional to a derivative of the signal inpuuted from the photodetector with respect to time, a detection circuit having a first peak voltage part outputting a first signal indicative of a first peak voltage and a second peak voltage part outputting a second signal indicative of a second peak voltage, and a comparison circuit for comparing the first peak voltage with the second peak voltage, so that a deviation of the converging light beam from an intended position on the surface of the recording medium is detected on the basis of a difference between the first and second peak voltages.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile