Droplet volume calculation method for a thermal ink jet printer

Abstract

A method for detecting the volume (Vol) of the droplets of ink ( ) ejected by a thermal ink jet printhead ( ), comprising a continuous driving cycle during which one or more thermal ejection actuators ( ) of the printhead ( ) are driven in pulsing fashion with a driving energy (Ep) progressively increasing from a condition where no droplets are ejected, while the printhead ( ) is maintained at a substantially constant stabilization temperature (Ts), notwithstanding the progressive increase in driving energy (Ep), by means of a heat control member ( ) which absorbs and dissipates an appropriate feedback energy. (Er) in the printhead ( ); wherein the quantities, correlated to each other in the course of the continuous driving cycle, of respectively the driving energy (Ep) fed to the ejection actuator ( ) and the feedback energy (Er) absorbed and dissipated by the heat control member ( ), to maintain the printhead ( ) at the stabilization temperature (Ts), are acquired for the purpose of defining an experimental characteristic ( ) representative of the continuous driving cycle, and in which the two linear end portions ( ) of this characteristic ( ) are compared with each other in order to calculate, on the basis of their reciprocal deviation (&Dgr;Ep), the volume (Vol) of the droplets of ink ( ) ejected by the ink jet printhead ( ).