Ink jet printer having driver circuit for generating warming and firing pulses for heating elements

An ink jet printing apparatus comprising:

• a print cartridge including at least one resistive heating element in at least one chamber capable of containing ink, and having an orifice;
• and
• a driver circuit, electrically coupled to said print cartridge, for applying to said resistive heating element a warming pulse and a firing pulse separated from one another by a delay period, said warming pulse being capable of causing said resistive heating element to warm a portion of ink provided in the chamber so as to form a thermal boundary layer within said ink and said firing pulse being applied while the thermal boundary layer is in the ink and being capable of causing said resistive heating element to produce a vapor bubble in said chamber which causes a droplet of the ink to be ejected from said chamber orifice, wherein energy diffused in the thermal boundary layer cooperates with energy applied by the firing pulse to increase the size of the thermal boundary Layer prior to nucleation.

An apparatus for generating liquid droplets having a single color comprising:

• a cartridge including at least one resistive heating element in at least one chamber capable of containing liquids and having an orifice;
• and
• a driver circuit for applying to said resistive heating element a warming pulse and a firing pulse separated from one another by a delay period, said warming pulse being capable of causing said resistive heating element to warm a portion of liquid provided in the chamber, said warming pulse and said delay period cooperating to form a thermal boundary layer in the liquid, and said firing pulse being applied while the thermal boundary layer is in the liquid and being capable of causing said resistive heating element to produce a vapor bubble in said chamber which causes a resultant droplet of the liquid to be ejected from said chamber orifice, wherein energy diffused in said thermal boundary layer cooperates with energy applied by the firing pulse to increase the size of the thermal boundary layer prior to nucleation and cause the resultant droplet to have a mass of about 20 nanograms to about 40 nanograms and to be ejected from said chamber orifice at a velocity of about 300 inch/s to about 600 inch/s.

An apparatus for generating liquid droplets having a plurality of colors comprising:

• a cartridge including at least one resistive heating element in at least one chamber capable of containing liquid and having an orifice;
• and
• a driver circuit, electrically coupled to said cartridge, for applying to said resistive heating element a warming pulse and a firing pulse separated from one another by a delay period, said warming pulse being capable of causing said resistive heating element to warm a portion of liquid provided in the chamber, said warming pulse and said delay period cooperating to form a thermal boundary layer in the liquid, and said firing pulse being applied while the thermal boundary layer is in the liquid and being capable of causing said resistive heating element to produce a vapor bubble in said chamber which causes a resultant droplet of the liquid to be ejected from said chamber orifice, wherein energy diffused in said thermal boundary layer cooperates with energy applied by the firing pulse to increase the size of the thermal boundary layer prior to nucleation and cause the resultant droplet of the liquid to have a mass of about 10 nanograms to about 25 nanograms and to be ejected from said chamber orifice at a velocity of about 400 inch/s to about 700 inch/s.

A mono ink jet printing apparatus comprising:

• a print cartridge including at least one resistive heating element in at least one chamber capable of containing ink and having an orifice;
• and
• a driver circuit, electrically coupled to said print cartridge, for applying to said resistive heating element warming and firing pulses separated by a delay period, said warming pulse being capable of causing said resistive heating element to warm a portion of ink provided in the chamber, said warming pulse and said delay period cooperating to form a thermal boundary layer in the ink, and said firing pulse being applied while the thermal boundary layer is in the ink and being capable of causing said resistive heating element to produce a vapor bubble in said chamber which causes a droplet of the ink to be ejected from said chamber orifice, wherein energy diffused in said thermal boundary layer cooperates with energy applied by the firing pulse to increase the size of the thermal boundary layer prior to nucleation and cause said droplet of the mono ink to have a mass of about 20 nanograms to about 40 nanograms and to be ejected from said chamber orifice at a velocity of about 300 inch/s to about 600 inch/s.

A color ink jet printing apparatus comprising:

• a print cartridge including at least one resistive heating element in at least one chamber capable of containing ink and having an orifice;
• and
• a driver circuit, electrically coupled to said print cartridge, for applying to said resistive heating element warning and firing pulses separated by a delay period, said warming pulse being capable of causing said resistive heating element to warm a portion of ink provided in the chamber, said warming pulse and said delay period cooperating to form a thermal boundary layer in the ink, and said firing pulse being applied while the thermal boundary layer is in the ink and being capable of causing said resistive heating element to produce a vapor bubble in said chamber which causes a droplet of the ink to be ejected from said chamber orifice, wherein energy diffused said thermal boundary layer cooperates with energy applied by the firing pulse to increase the size of the thermal boundary layer prior to nucleation and cause said droplet of the color ink to have a mass of about 10 nanograms to about 25 nanograms and to be ejected from said chamber orifice at a velocity of about 400 inch/s to about 700 inch/s.

An ink jet printing apparatus comprising:

• a print cartridge including at least one resistive heating element in at least one chamber capable of containing ink and having an orifice;
• and
• a driver circuit, electrically coupled to said print cartridge, for applying to said resistive heating element a single warming pulse and a firing pulse separated from one another by a delay period, said warming pulse being capable of causing said resistive heating element to warm a portion of ink provided in the chamber, said single warming pulse and said delay period cooperating to form a thermal boundary layer in the ink, and said firing pulse being applied while the thermal boundary layer is in the ink and being capable of causing said resistive heating element to produce a vapor bubble in said chamber which causes a resultant droplet of the ink to be ejected from said chamber orifice with a momentum, wherein energy diffused in said thermal boundary layer cooperate with energy applied by the firing pulse to increase the size of the thermal boundary layer prior to nucleation and thereby increase the momentum of said resultant droplet when compared with a droplet resulting when said resistive heating element receives a single firing pulse which applies an energy amount substantially equal to a combined energy amount of said warning pulse and said firing pulse.

An apparatus for generating liquid droplets comprising:

• a cartridge including at least one resistive heating element in at least one chamber capable of containing liquid and having an orifice;
• and
• a driver circuit, electrically coupled to said cartridge, for applying to said resistive heating element a single warming pulse and a firing pulse separated from one another by a delay period, said warming pulse being capable of causing said resistive heating element to warm a portion of liquid provided in the chamber, said single warming pulse and said delay period cooperating to form a thermal boundary layer in the liquid, and said firing pulse being applied while the thermal boundary layer is in the liquid and being capable of causing said resistive heating element to produce a vapor bubble in said chamber which causes a resultant droplet of the liquid to be ejected from said chamber orifice with a momentum, wherein energy diffused in said thermal boundary layer cooperates with energy applied by the firing pulse to increase the size of the thermal boundary layer prior to nucleation and thereby increase the momentum of said resultant droplet when compared with a droplet resulting when said resistive heating element receives a single firing pulse which applies an energy amount substantially equal to a combined energy amount of said warming pulse and said firing pulse.