Patent ID: 8740378

Claim:
A method comprising: during a first pass of a handheld device over a print medium, depositing, by the handheld device, a tagging substance in a tagging pattern on the print medium, wherein the tagging substance is different from a printing substance used by the handheld device to print an image on the print medium; during a second pass of the handheld device over the print medium, sensing, by a sensor of the handheld device, at least part of the tagging pattern, wherein the sensor is disposed such that during the second pass, the sensor moves over the tagging substance that was deposited on the print medium during the first pass; based upon the sensor sensing at least part of the tagging pattern as the sensor moves over the tagging substance during the second pass, determining at least one of (i) a position of the handheld device and (ii) a velocity of the handheld device; and during the second pass, depositing, by the handheld device, the printing substance on the print medium, wherein the printing substance is deposited on the print medium based on the at least one of (i) the position that is determined and (ii) the velocity that is determined.