Abstract: A method for controlling the boldness of printing via control of the number of ink droplets ejected from a drop on demand ink jet apparatus for producing each ink dot upon a recording medium, the apparatus including at least one transducer operable for producing a pressure disturbance within an associated ink chamber for ejecting an ink droplet from an associated orifice the method comprising the steps of operating the transducer in an iterative manner for selectively producing a predetermined plurality of successively equal or higher or lower amplitude pressure disturbances within the ink chamber, or some combination thereof, for causing a predetermined plurality of successively equal or higher or lower velocity ink droplets, or some combination thereof, to be ejected from the orifice of the ink jet apparatus, within a time period permitting the ink droplets to either merge in flight or upon striking a recording medium, thereby controlling the size of the "ink spot" so printed upon the recording medium.

Abstract: The volume of ink ejected from an ink jet printing apparatus during one cycle of operation for printing a dot upon a recording medium is controlled within that cycle of operation by operating the ink jet apparatus via the application of a pulse train having a periodicity equivalent to the dominant resonant frequency of the ink jet apparatus. An electrical signal in the form of an earlier pulse train is followed by at least one additional electrical signal or pulse having a time delay and an ink jet transducer is selectively gated on or off by the electrical signals.

Abstract: A method for improving droplet aim accuracy when operating an ink jet apparatus for ejecting ink droplets having velocities below 3.5 meters per second comprises the steps of first applying a primary electrical pulse to a transducer of the ink jet apparatus, for initiating the ejection of an ink droplet from an associated orifice via the production of a first pressure disturbance within the associated ink chamber of the ink jet; and thereafter prior to the break-off of the ink droplet from the orifice, applying an auxiliary pulse to the transducer, whereby the auxiliary pulse has a peak amplitude that is one-third that of the peak amplitude of the primary pulse, the latter causing a second pressure disturbance within the ink chamber of the ink jet, for causing the ink droplet to break off earlier and closer to the center of the orifice relative to the time and location of break-off in the absence of using the auxiliary pulse.