GB1449354A - Web printing - Google Patents

Abstract

1449354 Printing VLISCO BV 11 Feb 1974 [13 Feb 1973] 06078/74 Heading B6C A web carrying a primary pattern, e.g. mark 12, is overprinted with a secondary pattern by passing the web between at least one pressure roller and at least one printing roller, characterized in that the location of the secondary pattern in relation to the primary pattern is controlled on the basis of detection of markings on the web controlling the circumferential speed of the printing roller, the printing roller being maintained in slipping contact with the web. As shown, three printing rollers 3, 4 and 5 are used, and are driven from 30, as is the pressure roller 2 via variator 31. Variator 31 enables the set of printing rollers and the pressure roller to be varied in unison, and variator 34 enables the set of printing rollers to be varied in unison. Each printing roller carries a series of cams, e.g. 152, 152<SP>1</SP>, 252, 252<SP>1</SP> on roller 3, which coact with microswitches so giving an indication of the position of the roller. Detectors 7, 8 and 9 detect the primary pattern on the web, and the signal therefrom is compared with the output of the microswitches associated with the cams. The output of detector 8 compared with the cams on roller 3 controls motor 37 driving differential gear 35 to give an overall adjustment. Detectors 7 and 9 make the same sort of adjustment but only affect roller 4 and 5, respectively through motors 46 and 47, respectively.