A cleaning system for a continuous ink jet printer includes a first
solvent supply conduit connected to a solvent source for conveying
solvent through a supply opening and onto the front face of the print
head. A second solvent supply conduit is connected to the solvent source
for conveying solvent through a supply opening and onto a surface of the
catcher. The solvent that is supplied to the print head and the catcher
is removed under vacuum and returned to the ink supply system. The
cleaning system may include an orifice unclogging mechanism that causes
said solvent disposed on said front face to flow into said orifice in the
reverse of the direction ink flows through said orifice for printing. The
cleaning system may also include a piezoelectric element for generating a
stress wave in the print head during cleaning. The piezoelectric element
may comprise a piezoelectric oscillator that is also used during printing
to creates perturbations in the ink flow at the nozzle so as to generate
a stream of spaced drops from the nozzle.