Liquid jet method, recording head using the method and recording apparatus using the method

A recording apparatus comprising:

• a recording head having an ejection outlet and ejection energy generating means;
• a driving circuit for driving the ejection energy generating means;
• and
• a liquid disposed in said recording head for being discharged by a bubble produced by heating with said ejection energy generating means, the liquid including a major component, wherein a non-dimensional number Z which is determined by the physical nature of the liquid, a heat flux and a configuration of the passage and which is specific to a recording head is not less than 0.5 and not more than 16;
• where
• Z.ident.(.pi./6).sup.1/2 Tgk(P.sub.g /q.sub.0).sup.3/2 /(.rho..sub.g Lg.multidot.a.multidot.S.sub.H A).sup.1/2 ;
• Tg is a superheat limit temperature of the major component of the liquid;
• Pg is a saturated vapor pressure of the major component of the liquid at temperature Tg;
• .rho.g is a saturated vapor density of the major component of the liquid at temperature Tg;
• Lg is a latent heat of vaporization of the major component of the liquid at temperature Tg;
• k is a heat conductivity of the major component of the liquid at the temperature of the recording head before heating;
• a is a thermal diffusivity of the major component of the liquid at the temperature of the recording head before heating;
• q.sub.0 is a flux of the heat which heats the liquid;
• S.sub.H is an area of that part (heating surface of the heat generating element) which heats the liquid;
• A is an inertance of the passage under the conditions that the heating surface is a pressure source, that the liquid supply opening and the liquid ejection opening are open boundaries, and that the wall defining the passage is a fixed boundary;
• and
• .pi. is the number .pi., whereby said heating is produced with good thermal efficiency.