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:
Sep. 26, 1995
Filed:
Mar. 05, 1993
Kazuhisa Aruga, Suwa-shi, Nagano-ken 392, JP;
Yoshiaki Fukuda, Suwa-shi, Nagano-ken 392, JP;
Yoshikazu Ito, Suwa, JP;
Other;
Abstract
The invention provides an drive coil protection apparatus and method and a printer incorporating the apparatus. A rank memory stores a preset rank value associated with a reference drive coil in the print head of a printer. The preset rank value characterizes inherent deviations associated with the reference drive coil. The deviations result from manufacturing process, etc. A judgment value memory stores a plurality of sets of mode judgment values. Each set of mode judgment values corresponds to a particular rank value. Each mode judgment value represents a threshold value for determining the thermal condition of the print head and for selecting an appropriate operating mode for the print head. A head information detector detects the voltage drop across the reference drive coil to measure the change in the resistance of the reference drive coil. The voltage drop is digitized for accuracy measurement. The change in temperature of the reference drive coil can thus be determined. An operating mode selection circuit compares the digitized voltage drop with a particular set of mode judgment values in the judgment value memory corresponding to the preset rank value. Then, the operating mode selection circuit selects a suitable operating mode for the print head in accordance with the comparison. Thus, burnout of the print head can be prevented without reducing the operating efficiency of the printer.