Digital phase control for ink jet printer

Claim 2

In an ink jet printer having a transducer for vibrating a nozzle at a predetermined frequency to produce droplets having a selected phase relation with applied, variable, input information charges induced thereon by an input information source energizing a charging electrode for correspondingly varying deflection of said droplets in an electric field between deflecting electrodes, apparatus for varying the phase relation between said transducer vibrations and said applied charges comprising: circuit means connected to said charging electrode for applying, in response to an initiation signal, input information signals to said droplets and, in the absence thereof, applying calibration signals to droplets to be discarded; means providing a train of clock pulses of fixed frequency; frequency dividing means connected to said clock pulse means for energizing said transducer means at said predetermined frequency; counter means of predetermined capacity connected to said clock pulse means and said circuit means for cyclically counting said pulses and producing an initiation signal during each counting cycle at said predetermined frequency; detecting means for said discarded droplets having a plurality of sensor locations, each said location producing an output signal peculiar to droplet presence thereon; and control means responsive to said output signals to alter the number in said train of clock pulses at said counter means during a counting cycle and change the time of said count cycle and thereby the frequency of said initiation signal.

Claim 3

Apparatus as described in claim 1, wherein said control means includes means for generating sampling signals for enabling change of said phase relation and gating means connected to Said clock pulse means and sampling signal means, being operable for selecting certain said output signals to be effective to change said count cycle time.

Claim 4

Apparatus as described in claim 2, wherein said gating means is rendered operable by the occurrence of a sampling signal in predetermined relation with one of said clock pulses.

Claim 5

Apparatus as described in claim 3 wherein said sampling signals occur at a frequency less than said calibration signal frequency.

Claim 6

Apparatus as described in claim 1, wherein said detecting means has two sensor locations and produces respective output pulses peculiar thereto; and said control means is responsive to said output signals to alter said train of clock pulses and initiation signals so that subsequent ones of said calibration signals charge said discard droplets for deflection to the other of said locations.

Claim 7

Apparatus as described in claim 1 wherein the output signals of each said location alter the number of pulses in said train in a particular manner.

Claim 8

Apparatus as described in claim 1 wherein said predetermined calibration signal frequency is the same as said nozzle vibration frequency.

Claim 9

Apparatus as described in claim 1, wherein said detecting means has first and second sensor locations and produces respective first and second output signals; and said control means is responsive to said first output signal to add a pulse to said train of clock pulses supplied to said counter means, and is responsive to said second output signals to delete a pulse from said train of clock pulses supplied to said counter means.

Claim 10

Apparatus as described in claim 1, wherein the frequency of said clock pulses is an integral multiple of the frequency of said calibration signal frequency.

Claim 11

Apparatus as described in claim 1 wherein said calibration signal frequency is the same as said nozzle vibration frequency and said clock pulse frequency is an integral multiple thereof.

Claim 12

In an ink jet printer system wherein ink under pressure is delivered to a nozzle which is vibrated at a predetermined frequency by a transducer means to produce a stream of drops and a charging electrode is positioned adjacent said nozzle to charge said drops in a selected phase relation with information signals from input information signal means applied to said electrode for producing deflection of said drops in accordance with said information input signals as said drops move in an electric field between a pair of deflecting electrodes, apparatus for varying the phase relation between the formation of said drops and said information input signals comprising; circuit means including calibration signal means and said input information signal means connected to said charging electrode for applying to said charging electrode, in response to an initiation signal, calibration signals and information input signals so that all drops not charged by said information input signals are charged by said calibration signals; a source of clock pulses of fixed frequency; frequency dividing means connected to said clock pulse source for energizing said transducer means at said predetermined frequency; pulse counter means connected to said source and said circuit means for supplying an initiating signal at said predetermined frequency to said input information signal means and said calibration signal means concurrently; means for detecting said drops receiving a calibration charge thereon and for producing first and second output signals indicative respectively of the drop presence in a first location and in a second location thereon; means responsive to said first output signals from said detecting means for adding a count to said counter means; and means responsive to said second output signals from said detecting means for deleting a count from said pulse train to said counter means.

Claim 13

In an ink jet printer system wherein ink under pressure is delivered to a nozzle which is vibrated at a predetermined frequency by a transducer means to produce a stream of drops and a charging electrode is positioned adjacent said nozzle to charge said drops in a selected phase relation with information signals from input information signal means applied to said electrode for producing deflection of said drops in accordance with said information input signals as said drops move in an electric field between a pair of deflecting electrodes, apparatus for varying the phase relation between the formation of said drops and said information input signals comprising; circuit means including calibration signal means and said input information signal means connected to said charging electrode for applying to said charging electrode, in response to an initiation signal, calibration signals and information input signals so that all drops not charged by said information input signals are charged by said calibration signals; a source of clock pulses of fixed frequency; frequency dividing means connected to said clock pulse source for energizing said transducer means at said predetermined frequency; pulse counter means connected to said source and said circuit means for supplying an initiating signal at said predetermined frequency to said input information signal means and said calibration signal means concurrently; means for detecting said drops receiving a calibration charge thereon and for producing first and second output signals indicative respectively of the drop presence in a first location and in a second location thereon; means responsive to said first output signals from said detecting means for adding a count to said counter means; and means responsive to said second output signals from said detecting means for deleting a count from said pulse train to said counter means.

Claim 14

In an ink jet printer system in which pressurized ink issues from a nozzle vibrated by a traNsducer means to produce a stream of droplets that receive in a selected phase relation from a charging electrode at the time of formation a charge representative of information from an information input means to establish a subsequent marking or discard position upon passing through an electric field between a pair of deflection electrodes, apparatus for varying the phase relation between said transducer vibration and said applied charge comprising: circuit means including calibration signal means and said information input signal means connected to said charging electrode for applying, in response to an initiation signal, said calibration signal and said information input signals to said charging electrode so that all drops not charged by information input signals are charged by said calibration signal for discard; gutter means catching said discard drops operable to produce first and second output signals indicative of drop impact in a first or a second location thereon, respectively; clock pulse means for producing a train of pulses at a fixed frequency greater than that of said calibration signal; frequency dividing means connected to said clock pulse means for energizing said transducer means at said predetermined frequency; counter means of predetermined capacity connected to said circuit means and advanced by said clock means operable to provide an initiating signal at said predetermined frequency to said charging circuit means upon each reset of counter means; and means responsive to said first signals from said gutter means for deleting one of said train of pulses from said clock means and operable in response to said second signals for inserting a pulse in said train of pulses to said counter means.

Claim 15

In an ink jet printer system in which pressurized ink issues from a nozzle vibrated by a traNsducer means to produce a stream of droplets that receive in a selected phase relation from a charging electrode at the time of formation a charge representative of information from an information input means to establish a subsequent marking or discard position upon passing through an electric field between a pair of deflection electrodes, apparatus for varying the phase relation between said transducer vibration and said applied charge comprising: circuit means including calibration signal means and said information input signal means connected to said charging electrode for applying, in response to an initiation signal, said calibration signal and said information input signals to said charging electrode so that all drops not charged by information input signals are charged by said calibration signal for discard; gutter means catching said discard drops operable to produce first and second output signals indicative of drop impact in a first or a second location thereon, respectively; clock pulse means for producing a train of pulses at a fixed frequency greater than that of said calibration signal; frequency dividing means connected to said clock pulse means for energizing said transducer means at said predetermined frequency; counter means of predetermined capacity connected to said circuit means and advanced by said clock means operable to provide an initiating signal at said predetermined frequency to said charging circuit means upon each reset of counter means; and means responsive to said first signals from said gutter means for deleting one of said train of pulses from said clock means and operable in response to said second signals for inserting a pulse in said train of pulses to said counter means.