Method and apparatus for selective multi-resonant operation of an ink jet controlling dot size

Claim 1

A method for operating a drop-on-demand ink jet printing system in a resonant mode for providing high resolution printing upon a recording medium, said system comprising an ink jet having an ink cavity, an orifice communicating with said ink cavity, a transducer means in communication with said ink cavity, a source of electrical drive pulses or signals repeatable at a drop-on-demand drop production rate, said transducer means responsive to said electrical drive signals to fill said ink cavity and to force droplets of ink from said orifice, said method comprising the following steps: (1) actuating the transducer means in response to said electrical signals for filling the cavity of ink during a "fill cycle"; (2) actuating the transducer means in response to said electrical signals for firing a droplet of ink from said orifice during a "fire cycle", said electrical signals, each signal being separated by dead time, corresponding to the dominant fluidic or mechanical resonant frequency of the ink jet printing system created by operating said transducer means; and (3) repeating steps (1) and (2) so as to merge droplets into a single drop prior to or at the time the drop reaches the print medium whereby each drop size can be controlled.

Claim 2

A method for operating a drop-on-demand ink jet printing system in a resonant mode for providing high resolution printing upon a recording medium, said system comprising an ink jet having an ink cavity, an orifice communicating with said ink cavity, a transducer means in communication with said ink cavity, a source of electrical drive pulses or signals repeatable at a drop-on-demand drop production rate, said transducer means responsive to said electrical drive signals to fill said ink cavity and to force droplets of ink from said orifice, said method comprising the following steps: (1) actuating the transducer means in response to said electrical signals for filling the cavity of ink during a "fill cycle"; (2) actuating the transducer means in response to said electrical signals for firing a droplet of ink from said orifice during a "fire cycle", said electrical signals, each signal being separated by dead time, corresponding to the dominant fluidic or mechanical resonant frequency of the ink jet printing system created by operating said transducer means; and (3) repeating steps (1) and (2) so as to merge droplets into a single drop prior to or at the time the drop reaches the print medium whereby each drop size can be controlled.

Claim 15

A method of operating a drop-on-demand ink jet printing system in a resonant mode for providing high resolution printing upon a recording medium, said system comprising an ink jet having an ink cavity, an orifice communicating with said ink cavity, a transducer means in communication with said ink cavity, a source of electrical drive pulses or signals repeatable at a drop-on-demand production rate, responsive to said electrical drive signals to force droplets of ink from said orifice, said method comprising: operating said transducer means to produce a dominant resonant frequency within said ink cavity; repeatedly producing series of said electrical drive signals, each of said series being produced at a drop-on-demand production rate and each of signals within said series being separated by dead time, and having a repetition rate substantially equal to the dominant resonant frequency of the ink jet printing system or a subharmonic thereof; and actuating said transducer means with each of said electrical drive signals to produce an ink droplet having a controlled volume from said orifice, said ink droplets merging into a single drop of ink prior to or at the time the drop reaches the print medium for printing whereby each drop size can be controlled.

Claim 16

A method of operating a drop-on-demand ink jet printing system in a resonant mode for providing high resolution printing upon a recording medium, said system comprising an ink jet having an ink cavity, an orifice communicating with said ink cavity, a transducer means in communication with said ink cavity, a source of electrical drive pulses or signals repeatable at a drop-on-demand production rate, responsive to said electrical drive signals to force droplets of ink from said orifice, said method comprising: operating said transducer means to produce a dominant resonant frequency within said ink cavity; repeatedly producing series of said electrical drive signals, each of said series being produced at a drop-on-demand production rate and each of signals within said series being separated by dead time, and having a repetition rate substantially equal to the dominant resonant frequency of the ink jet printing system or a subharmonic thereof; and actuating said transducer means with each of said electrical drive signals to produce an ink droplet having a controlled volume from said orifice, said ink droplets merging into a single drop of ink prior to or at the time the drop reaches the print medium for printing whereby each drop size can be controlled.