Droplet generating method and apparatus thereof

A droplet generating apparatus comprising;

• a substrate including a heat sink;
• a plurality of heater sections arranged in staggered groups on the top and bottom of said substrate;
• and
• a plurality of droplet generating sections each of which is provided in corresponding relationship to an associated one of said plurality of heater sections, said droplet generating sections selectively generating the droplets by selective activation of said heater sections.

A liquid jet ejection process in which a pulse of energy is applied to a liquid chamber to heat liquid therein causing emission of a liquid droplet from an outlet orifice of said liquid chamber, said process comprising the steps of:

• generating a pulse of energy for use in heating the liquid;
• applying said pulse of energy to said chamber;
• controlling the generation of said pulse of energy to produce a period of increase in temperature in the liquid followed by a period of decrease in temperature, wherein the period of increase is less than the period of decrease;
• and
• further controlling said pulse of energy so that the period of increase in temperature causes said liquid to protrude progressively from the orifice, and so that the period of decrease in temperature causes the protruding liquid to constrict at the orifice to form a droplet followed by a retraction of the remaining liquid into said chamber and away from the orifice.

A liquid jet ejection process including:

• applying a pulse of energy to a chamber to heat liquid therein;
• controlling the application of said pulse of energy for a first period and at a first rate to produce an increase in the temperature of the liquid without formation of a bubble;
• controlling said pulse of energy for a second period and at a second rate, higher than that of the first rate, to produce a further increase in the temperature so that a bubble is formed and expands;
• and
• controlling said pulse of energy for a third period to produce a decrease in the temperature so that the bubble contracts, wherein the duration of said second period is less than that of said third period,
• wherein said expansion and contraction causes emission of a liquid droplet from an outlet orifice of the chamber.

A liquid jet ejection process including:

• applying a pulse of energy to a chamber to heat liquid therein;
• controlling the application of said pulse of energy at a first rate for a first period to produce an increase in the temperature of a liquid so that a bubble is formed and expands;
• and
• controlling said pulse of energy at a second rate, lower than the first rate, and for a second period to produce a decrease in the temperature of the liquid so that the bubble, contracts, wherein the duration of the first period is less than that of the second period,
• wherein said expansion and contraction of the bubble causes emission of a liquid droplet from an outlet orifice of the chamber.