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:
Jan. 25, 1983
Filed:
Jul. 31, 1980
Atsushi Noda, Yokohama, JP;
Takayoshi Hanagata, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A thermal head driving device is provided with a safety circuit for preventing the heating resistors of a thermal head from being burnt or reduced in life by an abnormal printing pulse signal being applied to the heating resistors. The device is also provided with a temperature correcting circuit for controlling the heating temperature of the heating resistors to prevent the printing density of the thermal head from being varied under the influence of the ambient temperature. The device is further provided with a compensation circuit for varying the printing conditions graded for each range of resistance values of the heating resistors in a plurality of thermal heads to prevent a difference in printing density from being caused by the difference between said resistance values. At least two of the safety circuit, the temperature correcting circuit and the compensation circuit are combined.