Patent ID: 6149258
Filing Date: 2000-11-21
Classification: B41J

Abstract:
An ink jet printing head for discharging ink droplets having a substantially uniform velocity and without satellite ink droplets having low velocities from a nozzle, in order to print an image of increased image quality, said print head comprising:an ink chamber,a plurality of pressure chambers having an inlet communicated with said ink chamber and said nozzle for discharging said ink droplets therethrough,a driving voltage;a piezoelectric element, disposed for each of said plurality of pressure chambers, for pressurizing each of said plurality of pressure chambers upon application of said driving voltage, said piezoelectric element having a natural period T1 of oscillation, each of said plurality of pressure chambers having a natural period T2 for propagation of waves, wherein T1 and T2 are selected so as to satisfy one of the following equations:T1=n.multidot.T2andT2=n.multidot.T1wherein n is a natural number not lower than two;said driving voltage having a rise time T3, wherein T3 is selected so as to satisfy the following equation:T3=mT2,wherein m is a natural number; andwherein said ink droplets discharged from said nozzle have said substantially uniform velocity and satellite ink droplets with low velocities are prevented from degrading said image quality.