Abstract: A thermal printer is operated to adjust the level of energy applied to print elements of a print head of the printer in response to selected changes in signals corresponding to the voltage from a power source used to provide energy to the printing elements. Voltage changes that occur during printing of a print can be ignored. In addition, voltage changes occurring when a printer is not being powered by a battery can also be ignored. Rapid decreases in voltage of the power source can be detected and accounted for. In addition, increasing voltages of the power source can also be determined and accounted for.

Abstract: A thermal printer, when operating under battery power, has an internal or battery ground. Static electricity is typically generated during normal operation of the printer. At least one static electricity discharge member is positioned in contact with a major surface of printing substrate at a location downstream from the location at which a thermal print head transfers ink from an ink transfer ribbon to the substrate. The at least one static electricity discharge member is electrically coupled to the internal ground so as to discharge static electricity build up that can otherwise damage electronic components of the printer.