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. 09, 1988
Filed:
Oct. 01, 1986
Brian W Damon, Lexington, KY (US);
Cary P Ravitz, Lexington, KY (US);
Carl J Voss, Lexington, KY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Heat accumulation in a thermal printhead is controlled by printing blocks of data along the print line in two passes when examination of the data shows the potential of excessive heating. The proportion of heat intensive or black parts in each block is determined by data processor 17 by examining the data for a line in memory 19. An accumulation is made assigning blocks having high heat density minus 2, blocks having intermediate heat density minus 1 and blocks having low heat density plus 1. When that figure is at minus two the next block is not printed until a second pass and the accumulation is set to zero. Where the accumulation is minus 1, print power is reduced for the next block, which is printed in the first pass. Excessive heat in the printhead results in machine damage and impaired print quality. A second pass is completely avoided where the data is such that this is unnecessary. This offers the potential of feeding ribbon only in blocks being printed, although ribbon feeding may be continued to achieve additional cooling.