Abstract An electrostatic, ink-jet printing apparatus wherein electrostatically charged ink is extracted from a nozzle in an axial direction by an electrostatic potential existing between the nozzle and a valving electrode. The droplets of ink are then deflected in orthogonal, lateral directions by two pairs of deflection electrodes in order to trace an indicium on the record medium. An additional pair of deflection electrodes is placed in the region upstream of the point in which droplet formation takes place. A sinusoidal voltage is applied between these additional deflecting electrodes, shaking the stream of ink in a lateral direction in order to facilitate droplet formation and promote uniform droplet size and spacing.
In apparatus for forming a succession of electrically charged liquid ink droplets of substantially uniform size and spacing and including means for generating an electrostatic field for taperingly drawing a stream of ink in a continuous liquid phase from a nozzle substantially along the axis thereof, the improvement comprising: a pair of electrodes, as shaking means, spaced from said nozzle and disposed in parallel about said stream along the stream taper whereat the circumference of the stream is no greater than the interval between varicosities that would develop in the stream in the absence of said shaking means for producing a periodically varying electrostatic potential field transverse to said stream and shifting the stream axis from the axis of the nozzle at a frequency corresponding to the frequency of droplet formation.
Claim 2
Dependent Claim
131 words
In apparatus for forming a succession of electrically charged liquid ink droplets of substantially uniform size and spacing and including means for generating an electrostatic field for taperingly drawing a stream of ink in a continuous liquid phase from a nozzle substantially along the axis thereof, the improvement comprising: a pair of electrodes, as shaking means, spaced from said nozzle and disposed in parallel about said stream along the stream taper whereat the circumference of the stream is no greater than the interval between varicosities that would develop in the stream in the absence of said shaking means for producing a periodically varying electrostatic potential field transverse to said stream and shifting the stream axis from the axis of the nozzle at a frequency corresponding to the frequency of droplet formation.