Imaging apparatus and method adapted to control ink droplet volume and void formation

An imaging apparatus adapted to control ink droplet volume and void formation, comprising:

• (a) a nozzle for ejecting an ink droplet therefrom, the ink droplet having a volume defined by heat energy supplied to the ink droplet and having a potential for void formation;
• (b) a heater element adapted to be in heat transfer communication with the ink droplet for supplying the heat energy to the ink droplet;
• and
• (c) a controller connected to said heater element for variably controlling the heat energy supplied by said heater element, said controller variably controlling the heat energy by variably controlling a plurality of voltage pulses sequentially supplied to said heater element from a voltage supply unit, each of the voltage pulses having a predetermined pulse amplitude, a predetermined pulse width and a predetermined time interval between pulses variably controlled by said controller, whereby the volume of the ink droplet ejected from said nozzle is variably controlled as said controller variably controls the pulse amplitude, pulse width and time delay and whereby void formation in the ink droplet is avoided as said controller variably controls the pulse amplitude, pulse width, and delay time.

An ink-jet printer adapted to control ink droplet volume deposited on a recorder medium disposed in the printer and adapted to avoid void formation in the ink droplet, the printer comprising:

• (a) a plurality of nozzles, each nozzle having a generally circular orifice for ejecting an ink droplet therefrom of a predetermined volume defined by heat energy supplied to the droplet, the orifice being disposed proximate the recorder medium for exit of the droplet through the orifice and onto the recorder medium;
• (b) a plurality of generally annular heater elements surrounding respective ones of the orifices, each of said heater elements adapted to be in heat transfer communication with a respective one of the ink droplets for supplying the heat energy to the ink droplet;
• and
• (c) a controller electrically connected to said heater elements for variably controlling the heat energy supplied by said heater elements, said controller variably controlling the heat energy by variably controlling a plurality of voltage pulses sequentially supplied to each heater element from a voltage supply unit so as to define a first pulse having a first predetermined pulse amplitude and a first predetermined pulse width, the first pulse delayed in time from a second pulse having a second predetermined pulse amplitude and a second predetermined pulse width, whereby the delay time, the first pulse amplitude and first pulse width and the second pulse amplitude and second pulse width supplied to each heater element are variably controlled as said controller variably controls the first and second pulses, whereby the heat energy supplied to each heater element is variably controlled as said controller variably controls the first pulse amplitude and first pulse width and the second pulse amplitude and second pulse width, whereby the volume of the droplet ejected from the orifice of each heater element is variably controlled as the heat energy supplied to each heater element is variably controlled, and whereby void formation in the droplet is avoided as said controller variably controls the heat energy.

An imaging method, comprising the steps of:

• (a) providing a nozzle adapted to eject a print fluid therefrom, the print fluid having a volume defined by heat energy supplied to the print fluid and having a potential for void formation;
• (b) providing a heater adapted to be in heat transfer communication with the print fluid for supplying the heat energy supplied to the print fluid;
• and
• (c) providing a controller adapted to variably control a plurality of voltage pulses supplied to the heater from a voltage supply unit in order to variably control the heat energy supplied by the heater, including the steps of:
• (i) providing each voltage pulse with a predetermined pulse amplitude and a predetermined pulse width, adjacent ones of the pulses being spaced-apart in time by a predetermined delay interval;
• (ii) variably controlling the pulse amplitude, pulse width or delay interval so that the volume of the print fluid ejected from the nozzle is variably controlled as the pulse amplitude, pulse width and delay time are variably controlled to control the heat energy;
• and (iii) avoiding void formation in the print fluid as the controller variably controls the pulse amplitude, pulse width and delay time to control the heat energy.

For use in an ink-jet printer, an imaging method of controlling ink droplet volume and void formation, comprising the steps of:

• (a) providing a nozzle adapted to eject an ink droplet therefrom, the ink droplet having a volume defined by heat energy supplied to the ink droplet and having a potential for void formation;
• (b) providing a heater element adapted to be in heat transfer communication with the ink droplet for supplying the heat energy to the ink droplet;
• (c) providing a controller adapted to variably control a plurality of voltage pulses supplied to the heater from a voltage supply unit in order to variably control the heat energy supplied by the heater element by variably controlling a plurality of voltage pulses sequentially supplied to the heater element, including the steps of:
• (i) providing each of the voltage pulses with a predetermined pulse amplitude and a predetermined pulse width, adjacent ones of the pulses being spaced-apart in time by a predetermined delay interval;
• (ii) variably controlling the pulse amplitude, pulse width or delay interval so that the volume of the ink droplet ejected from the nozzle is variably controlled as the controller variably controls the pulse amplitude, pulse width an delay time to control the heat energy;
• and (iii) avoiding void formation in the ink droplet as the controller variably controls the pulse amplitude, pulse width and delay interval to control the heat energy.