Abstract: A thermal transfer printing system in which a print scanning head is provided with a series of thermal heating elements. The elements are aligned in a column perpendicular to the line of printing. A sensor is provided to determine where the scanning head is aligned perpendicularly relative to the line of printing. More heating elements are provided on the head than are required for printing. Only those heating elements properly aligned with the line of printing are activated.

Abstract: In an ink jet printer, it is desirable to compensate the flight of the ink drops to correct for print errors caused by aerodynamic effects. The apparatus shown herein corrects the flight of ink drops for all aerodynamic effects, drop interactive and environmental. Correction for drop interactive effects can be accomplished in any of several well known ways. The additional correction for environmental effects is accomplished by scaling the drop interactive correction. The scale factor is first determined for static environmental conditions. Environmental conditions include the climate in which the printer operates and the specifications on the component parts of the ink jet printing assembly. The scale factor can be adjusted dynamically for changes in the environment. In particular, changes in air density of the environment are monitored and used to dynamically adjust the scale factor.

Abstract: The invention relates to an ink jet printer and in particular to correcting the flight path of drops from the printer to reduce print position error on the print media. Compensation values can be stored and retrieved for use by the printer to correct the flight of a drop to the print media. The compensation values are based on the pattern of print data representing the drops in the ink stream with the drop being compensated. To reduce the number of variables that must be dealt with, one or more portions of the print data can be grouped into one or more blocks and each block treated as having a single effect on the drop being compensated. However, basing the compensation value on one predetermined treatment of print drops as having individual effects or as having individual effects in combination with one or more group effects on the drop being compensated does not produce the optimum print appearance for all combinations of print data.