Ink jet recording apparatus for adjusting time constant of expansion/contraction of piezoelectric element

An ink jet recording apparatus comprising:

• a recording head comprising;
• at least one piezoelectric vibration element having a natural vibration cycle Ta,
• a pressure producing chamber corresponding to said at least one piezoelectric vibration element having a Helmholtz cycle Tc, a volume of said pressure producing chamber being changed in accordance with one of contraction and expansion of said at least one piezoelectric vibration element;
• an ink chamber, connected to said pressure producing chamber, for storing a reservoir of ink, said ink chamber communicating with a nozzle opening via said pressure producing chamber;
• wherein ink is supplied to said pressure producing chamber, from said ink chamber, and jets out from said at least one nozzle opening in response to displacement of said at least one piezoelectric vibration element;
• and
• a drive circuit, connected to said at least one piezoelectric vibration element, comprising:
• pulse signal generating means for dividing a single recording head drive period, during which a printing drop is formed, into n segments, n being an integer having a value of at least two, and an outputting in synchronism with a signal supplied from for external source, a drive signal having a charge pulse cycle TP having a first drive signal and a second drive signal;
• first drive signal outputting means for outputting said first drive signal for contracting said at least one piezoelectric vibration element at a first predetermined velocity;
• second drive signal outputting means for outputting said second drive signal for expanding said at least one piezoelectric vibration element at a second predetermined velocity;
• and
• time constant adjusting means for generating a plurality of time constants for a discharge rate of said second drive signal, the plurality of time constants being in one-to-one correspondence with said n segments, wherein an ink droplet most recently jet out from said at least one nozzle opening has a velocity which enables a combination of said ink droplet, in the air, with another ink droplet previously jet out from said at least one nozzle opening.