Patent ID: 6985264

Claim:
A method for calibrating an engraving amplifier in an electronic engraving machine for engraving printing cylinders for gravure printing, comprising the steps of: acquiring an engraving signal for actuating an engraving stylus of an engraving member from engraving signal values derived from engraving data representing desired tone values and a periodic vibration signal in an engraving amplifier that can be adjusted by setting electrical signal values corresponding to electrical settings for generating an engraving raster, said electrical signal values modifying at least one of the parameters “vibration”, “light”, “dark”, and “medium gradation”; with the engraving stylus, engraving cells into the printing cylinder, the actual dimensions of the cells representing engraved actual tone values; calculating transmission functions adjusted at the engraving amplifier which reproduce relationships between variations of the electrical signal values and resulting variations of geometric actual dimensions of the engraved cells; with the electrical signal values, engraving test cells for predetermined desired tone values corresponding to desired dimensions, and measuring their geometric actual dimensions; calculating difference values from the actual dimensions and the desired dimensions of the cells and by use of the transmission functions; correcting the electrical signal values by adding the difference values; the steps of engraving test cells and connecting the electrical signal values are repeated until the actual dimensions of the test cells are at least within a tolerance range about the desired dimensions, and to shorten calibration time, in each sequence of the steps from setting the electrical signal values through correcting the electrical signal values, comparing the actual dimensions of the cells to the desired dimensions; if the actual dimensions are outside the tolerance range, recalculating the transmission functions; computing new difference values by use of the recalculated transmission functions; and correcting the electrical signal values using the new difference values.