Method and apparatus for variation of ink droplet velocity and droplet mass in thermal ink-jet print heads

摘要

Variation of ink droplet velocity and droplet mass in thermal ink- jet print heads having at least one primary heater element is achieved by means of a circuit for generating time-shifted heating pulses. The heater element structure is such that there is at least one secondary heater element in addition to and physically separated from each primary heater element. The circuit for generating time-shifted heating pulses for the primary and secondary heater elements applies those pulses in such a way that a vapor bubble has already formed in the printing fluid on the secondary heater element at the point at which a vapor bubble starts to form in the printing fluid on the primary heater element.