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. 31, 2015
Filed:
Oct. 23, 2012
Tdk Corporation, Tokyo, JP;
Nobuo Furukawa, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
A powder sensor includes a piezoelectric element, an oscillator circuit, a phase determination circuit, and a powder presence/absence determination circuit. The oscillator circuit applies to the piezoelectric element an output signal having a frequency equal to or near a resonance frequency of the piezoelectric element. The phase determination circuit determines phase of a terminal voltage of the piezoelectric element relative to phase of the output signal from the oscillator circuit. The powder presence/absence determination circuit determines that powder is absent if the phase determination circuit determines, n consecutive times (where 'n' is an arbitrary integer satisfying n≧2), that the phase of the terminal voltage of the piezoelectric element, relative to the phase of the output signal from the oscillator circuit, satisfies a predetermined condition.