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:
Mar. 26, 2002
Filed:
Feb. 19, 1998
Itaru Watanabe, Kawasaki, JP;
Shinji Takagi, Kawasaki, JP;
Soichi Hiramatsu, Hachioji, JP;
Osamu Sato, Chigasaki, JP;
Kenta Udagawa, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Precision of detecting existence/non-existence of a liquid container and a liquid level in the container is improved even if the detection is performed by a single sensor, or even if the S/N ratio of the detection is low, the detected results can be discriminated from one another. For this, a concave polyhedron is provided in the center of the bottom surface of an optical prism in order to reduce the amount of light reflected on the bottom surface of the optical prism and returned to a photoreceptor. Moreover, a reflection curved surface having a quadratic surface e.g. spherical surface or paraboloid, is provided on the bottom surface of an ink tank, for reflecting light emitted by an optical unit consisting of a light emission device and a photoreceptor. By virtue of this, even in a case where an arrangement angle or position of the optical unit is deviated to some extent, sufficient amount of light for the photoreceptor can be received, making it possible to accurately detect existence/non-existence of ink and/or existence/non-existence of an ink tank.