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:
Oct. 24, 1989
Filed:
Dec. 21, 1987
Applicant:
Inventors:
Koichi Isono, Hikone, JP;
Ikuo Sho, Hikone, JP;
Assignee:
Dainippon Screen Mfg. Co., Ltd., Kyoto, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03D / ;
U.S. Cl.
CPC ...
250561 ;
Abstract
Photosensors having light emitting elements and light receiving elements are provided in a path for carrying a film. The light emitting elements emit periodic pulsed light. When the film is present in the positions of the photosensors, the periodic pulsed light is reflected by the film to enter the light receiving elements, whereby presence of the film is detected. Activation time and activation interval of the light emitting elements for generating the periodic pulsed light are determined so that accumulated exposure value in each portion on the film is less than a critical exposure value of photosensitive material provided in the film.