Apparatus for making graphic products having a calibrated print head,

Abstract

In an apparatus for printing graphic images on sheet material. The thermal print head has a linear array of heating elements extending in the y-coordinate direction, and is movable between a home position and a command position in that direction for printing graphic images wider than the length of the linear array. With the print head in the home position, a first group of heating elements at the upper end of the print head are actuated to print a plurality of first indicia equally spaced relative to each other in the y-coordinate direction. The print head is then moved upwardly in the y-coordinate direction to the command position whereby a second group of heating elements at the lower end of the print head overlap the first indicia. The print head then prints a plurality of second indicia in the spaces defined between adjacent first indicia with the second group of heating elements, and the print head is moved incrementally in the y-coordinate direction between printing sequential second indicia. The second indicia equally spaced between adjacent first indicia is then selected, and the command position of the print head is adjusted based on its total incremental movement corresponding to the selected second indicia to calibrate the movement of the print head in the y-coordinate direction.