What is printhead resistance?

29th July, 2020

A thermal printhead comprises a linear array of printing elements, or “dots”. Each dot is a tiny resistor and printhead resistance is a measure of the total resistance of all the dots. This resistance will vary from printhead to printhead due to manufacturing tolerance. The actual resistance of a printhead fitted to a thermal printer is critical to correct operation because the printhead resistance is a key parameter used by a control algorithm to decide on the amount of power to supply to the printhead in order to achieve good print quality.

Many printers require the user/engineer to manually enter the printhead resistance via dip-switches on the main control PCB each time a new printhead is fitted to the machine. This can lead to errors and consequent poor performance of the machine. The Zodiac avoids this by allowing the operator to enter the resistance (4-DIGIT) value using the main CLARiTY user interface.