Patent ID: 8405879
Filing Date: 2013-03-26
Classification: B41F,B41P,G03G

Abstract:
1. A method for calibrating a position of a first register line in a register mark for a multi-color printing machine, said first register line consisting of a first color which does not offer sufficient light/dark or dark/light contrasts with respect to a printing material in order to allow a detection above a certain threshold value on a register sensor measuring light/dark and dark/light transitions between the individual register lines and the printing material underneath, said method including the following steps: a) printing of a plurality of register marks, each consisting of at least one starting line, a background line and a first register line, said background line consisting of a second color which offers sufficient contrast with respect to the first color for a detection above the specified threshold value on the register sensor ( said background line, in transport direction seen, having a width that is by X mm greater than the first register line, and said starting line, said background line and said first register line being printed with the use of pre-determined control parameters, which, in the normal case, cause the first register line to be printed on the background line; b) detecting, whether the first register line has been recognized by the register sensor above the pre-determined threshold value as being completely positioned on the background line; c) changing of at least one of the pre-determined control parameter for printing the first register line in order to shift the register line +Y mm with respect to the position pre-specified by the pre-determined control parameter in the direction of its width, when the first register line ( d) printing of a plurality of register marks of the above type with the use of at least one changed control parameter for printing the first register line; e) detecting, whether the first register line has been recognized by the register sensor above the pre-determined threshold value as being completely positioned on the background line; f) renewed changing of the pre-specified control parameter for printing the first register line in order to shift the line by −Y mm with respect to the position that has been pre-specified by the pre-determined control parameter in the direction of its width, if the first register line is not recognized above the pre-determined threshold value as being completely positioned on the background line; g) printing of a plurality of first register marks of the above type with the use of the renewed, changed control parameter for printing the first register line; h) detecting, whether the first register line has been recognized by the register sensor above the pre-determined threshold value as being positioned completely on the background line; i) generating of a message when the first register line was recognized at no time above the pre-specified threshold value as being completely positioned on the background line; j) determining the position of the first register line on the background line if said register line was completely detected on the background line, and determining a changed control parameter for the first register line if the first register line, during printing with the pre-determined control parameter, deviates over a pre-specified threshold value from a rated position on the background line; and, k) providing the changed control parameter for subsequent processes.