Abstract: A handheld printer is movable across a target object to print while moving in a desired printing field. The printer has a position detector and a microprocessor controller for detecting the position of a printing member and activating the printing member at a plurality of successive printing locations. The printer may use thermal or inkjet printing and has user feedback and input. A mechanical position detector enables the printer to be used without a mechanical paper drive mechanism. The printer allows image rotation under control of a four-position switch and scaling of the image using distance and printline based scaling. The printer may be controlled by an external controller through a cable or a remote signal source. An alternative embodiment of the printer uses a vacuum-type arrangement to attract and hold the printer to the surface being printed. The printer may be line or battery-powered.

Abstract: A label printer having a stepping motor and the ability to dynamically accurately control longitudinal label registration as a function of steps of the stepping motor. The effective length of the steps moving the labels between a known point prior to the printhead and the printhead are monitored and the number of steps actually used to move the labels between the known point and the printhead are adjusted as a function of changes in the effective step length. In one embodiment, a sensor counts the steps between consecutive labels or averages a number of labels to determine the effective step length. In another embodiment, a sensor detects the start of label and start of printing on the label and the step distance between the two is used to determine the effective step length.

Abstract: A method and apparatus for controlling a thermal printhead. In response to a sequence of print commands, the method and apparatus generate an energization signal for each thermal print element in the printhead. In one embodiment, the energization is a function of at least the present print command and a future print command. In certain embodiments, the energization signal may also be a function of a past print command, print commands for at least one adjoining print element, and other parameters. Each print element in the printhead can, accordingly, be maintained at a proper temperature to ensure long printhead life and cause the printhead to generate sharp images.