Patent ID: 6786569
Filing Date: 2004-09-07
Classification: B41J

Abstract:
Dot matrix printing method for printing an image on a printing medium with reduced banding, by moving, relative to the printing medium, a printing head, in a fast scan direction (Y), during a plurality of printing passes, the printing head having a contiguous set of equally spaced marking elements, the marking elements available to be fired at firing moments being a set of active marking elements, the length of the active marking elements on the printing head in a slow scan direction (X) perpendicular to the fast scan direction (Y) being the head length, the method comprising the step of:printing the image as at least two sub-images during the plurality of printing passes by mutually interstitial printing steps and/or interlacing steps, wherein the printing step comprises moving the printing medium relative to printing head with a transport distance step in the slow scan direction (X), between the printing passes of the at least two sub-images, whereby the sum of all transport distance steps after writing one swath of each sub-image is exactly equal to the head length, the transport distance steps being performed in at least two different step lengths and wherein the image is divided into N sub-images, N being the number of colours used multiplied by the number of mutually interstitial printing steps and multiplied by the number of interlacing steps (N=C*P*I).