To eliminate alignment error of small and irregular dots by applying a rod linearity correction data.
Because of the order of a print head, i.e., black, yellow, red and cyan (K, Y, M, C), adjacent pen-to-pen print errors (K-Y, Y-M, M-C) is smaller than an K-C error at all times and they are accumulated to become the K-C error. The K-C error along the scanning axis is measured by means of a printer line sensor. Furthermore, a measuring procedure takes into account of the intermediate point M of error and the intermediate point P of error range R. A correction procedure selects the nonlinear combination of two statistic values M and P. That combination is calculated using two weighting functions dependent on the error range R. In the determination 152 of correction data, comparison 155 of the error statistics of the entire rod and the error statistics of a part of the rod is related to single offset memory step 158. That step is used for alignment between heads.
MONTACLAIR GUILLAUME
POZUELO FRANCISCO JAVIER
