PROCEDE ET DISPOSITIF POUR AUGMENTER LA VITESSE D'IMPRESSION D'UNE IMPRIMANTE A PROJECTION D'ENCRE A VITESSE NON LINEAIRE DE LA TETE D'IMPRESSION

• Main Author: PHILLIP K. HOSKINS, HARMON W. JOHNSON, RICHARD H. DARLING ET FRANCIS J. PERRY
• Format: Patent
• Language: French
• Published: 22.09.1978
• Subjects: CALCULATING; COMPUTING; CORRECTION OF TYPOGRAPHICAL ERRORS; COUNTING; HANDLING RECORD CARRIERS; i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; LINING MACHINES; PERFORMING OPERATIONS; PHYSICS; PRESENTATION OF DATA; PRINTING; RECOGNITION OF DATA; RECORD CARRIERS; SELECTIVE PRINTING MECHANISMS; STAMPS; TRANSPORTING; TYPEWRITERS

Commande d'imprimante. Le circuit comporte deux boucles à verrouillage de phase, l'une constituant un circuit d'interpolation est commandee par un codeur 50 appliquant aux bornes 52 un train d'impulsions traduisant le passage de la tête d'impression par les positions d'impressions successives; l'autre est commandée par un codeur 54 fournissant des impulsions traduisant les vitesse et sens de rotation du moteur entraînant la tête. Une comparaison de phase des deux boucles est effectuée en 68. Traitement de données. Inkjet printers with variable relative speed between the printing mechanism and the recording medium produce uneven print quality, as the trajectory of the ink droplets depends on the lateral velocity of the nozzle. The problem is overcome by continuous calculation of the advance time for triggering the printing process on the basis of the measurement of the instantaneous speed of the printing mechanism and a determination of its travelling position. Measurement and calculation are carried out by means of an electronic circuit which contains at least one phase-stabilised loop (220) which comprises a phase comparator/detector (222) and a voltage-controlled square-wave generator (226) and a frequency divider (228). The loop (220) is supplied with positional information. Its analog output signal (speed) is supplied via an AD converter (236) and a register (258), its digital output signal (position) is supplied via counters (232, 240) to a processor (242) in which the advance time is calculated.