EP 0530748 A2 19930310 - Printer head modulation technique for thermal printers.
Title (en)
Printer head modulation technique for thermal printers.
Title (de)
Modulationstechnik eines Druckkopfes für thermische Drucker.
Title (fr)
Technique de modulation d'une tête d'impression pour imprimantes thermiques.
Publication
Application
Priority
US 75409791 A 19910903
Abstract (en)
The present invention relates to a technique including method and apparatus for modulating the power to thermal pixels of a thermal print head (18). The technique energizes each thermal pixel with a plurality of N-M idle power modulating pulses and a plurality of M print power modulating pulses during each line printing period. The idle power modulating pulses are used for substantially maintaining the thermal pixel at a first temperature which is (1) below a dye transfer temperature of a dye color on a dye carrier member, and (2) above a base temperature of a material forming a heat sink of the print head. The print power modulating pulses are used to raise the first temperature of the thermal pixel to a second temperature above the dye transfer temperature of the dye carrier member so as to cause an M dye color density level of N density levels of the dye color to be transferred from the dye carrier member to a receiver member engaging the dye carrier member opposite the thermal pixel, where M is a value between 0 and N. Alternatively, for modulating large area thermal pixels, two sequential sets of N power modulating pulses can be generated, each plurality of N pulses having M/2 print power modulating pulses. During a first line printing period, after a cold start, a plurality of idle power modulating pulses can initially be generated to raise each thermal pixel from the base temperature to the first temperature.
IPC 1-7
IPC 8 full level
B41J 2/355 (2006.01); B41J 2/36 (2006.01); B41J 2/365 (2006.01)
CPC (source: EP)
B41J 2/36 (2013.01); B41J 2/365 (2013.01)
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 0530748 A2 19930310; EP 0530748 A3 19930324; JP H05201054 A 19930810
DOCDB simple family (application)
EP 92114927 A 19920901; JP 23621192 A 19920903