Title (en)

PRINTER HEAD MODULATION TECHNIQUE FOR THERMAL PRINTERS

Publication

EP 0530748 A3 19930324 (EN)

Application

EP 92114927 A 19920901

Priority

US 75409791 A 19910903

Abstract (en)

[origin: EP0530748A2] 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

B41J 2/36

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)

Citation (search report)

• [Y] EP 0421353 A2 19910410 - SEIKO EPSON CORP [JP]
• [A] DE 3833746 A1 19900405 - SIEMENS AG [DE]
• [A] US 4568817 A 19860204 - LENG SVAY [JP], et al
• [Y] PATENT ABSTRACTS OF JAPAN vol. 10, no. 365 (M-542)(2422) 6 December 1986 & JP-A-61 160 257 ( RICOH CO LTD ) 19 July 1986
• [A] PATENT ABSTRACTS OF JAPAN vol. 13, no. 20 (M-785)(3368) 18 January 1989 & JP-A-63 230 368 ( CANON INC ) 26 September 1988
• [A] PATENT ABSTRACTS OF JAPAN vol. 7, no. 244 (M-252)(1389) 28 October 1983 & JP-A-58 131 080 ( CANON K.K. ) 4 August 1983
• [A] PATENT ABSTRACTS OF JAPAN vol. 11, no. 348 (M-642)(2795) 14 November 1987 & JP-A-62 128 767 ( TOKYO ELECTRIC CO LTD ) 11 June 1987

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