Patent ID: 7050193

Claim:
A method for high accuracy media positioning in a swath printer, comprising: mounting a computer-controlled printing element for movement along a swath axis for swath printing of an image on a print medium; moving the printing element along the swath axis and printing at least a portion of a swath of the image on the print medium; activating a media advance mechanism to provide a nominal advance movement between the printing element and the print medium to position for a fresh swath; moving the printing element along the swath axis; sensing the position of an edge of a just printed portion of said image which is nominally aligned with the scan axis, wherein said edge is a bottom edge of a previously printed swath in relation to a direction of print medium advance through the swath printer past the printing element; providing relative motion between the print medium and the printing element to accurately position the printing element in dependence on the sensed position of the edge of the just printed portion of the image to align the top edge of the next swath to be printed in relation to the bottom edge of the previously printed swath, wherein said step of providing relative motion is carried out on the fly as the portion of the image is being printed and the print element is moving in the scan axis.