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:
Aug. 18, 1987
Filed:
May. 08, 1985
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A thermal print head driving system supplies a predetermined number of driving pulses to each of a plurality of heat-producing elements arranged in a line to record a single dot of desired tone. The pulse width of driving pulse is controlled in accordance with the temperature at or in the vicinity of the heat-producing elements thereby allowing to maintain the density level of desired tone at constant. In another aspect of the present invention, it is so structured that driving pulses may be applied to the heat-producing elements in a continuous manner without producing a cooling period during switching between tone levels. In a further aspect of the present invention, it is so structured that a predetermined number of driving pulses for each of predetermined number of tone levels is altered in consideration of the data in at least one of preceding recording lines, thereby allowing to carry out a high speed recording operation without causing fluctuations in predetermined tone density level.