Print Hammer Flight Time Temperature Compensation Circuit
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
A method to control the flight time of print hammers is to control the time constant of the current in the hammer coil. Since temperature affects the resistance in the hammer coil, the approach to compensate for resistance changes is to maintain a constant time constant. This is explained in the following expression: T(c) = L over R also T(c) = L over V over I = LI over V. where L = inductance of a coil, V = coil applied voltage, I = coil current, and R = coil resistance.