EC-PACK EC-JET 2000, Manual

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User Manual The1.1 version of 2018 Guangzhou EC-PACK CO.LTD
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shutdown. Cleaning pump offers clean solvent to printhead through cleaning pipes to make sure
the surface of nozzle be cleaning before shutdown.
Similarly, when it is turned on, EC2000 can intelligently select the corresponding start-stop
procedure according to the duration and status of the shutdown to ensure that the machine is
always in the best startup and working state.
2.2.12.
、
Velocity of Drop
Ink velocity can impose a minor change in the mass of a drop, which will affect the final printing
position of the drop. However, precise placement of drops is more dependent on the speed of the
drops as they travel through the deflector plates;
For this reason, the velocity of drop (VOD) is constantly monitored and compared with the
optimum (VOD reference) value printed on the print head conduit. A “feedback loop” is used to
increase or decrease ink pressure, thus maintaining the correct speed of drops for accurate
placement and therefore quality of print.
2.3. Principles of Operation
A conducting ink is supplied under pressure to an ink gun and forced out through a small nozzle of
typically 40 to 70 micro diameters. As it passes through the nozzle the liquid is piezo-electrically
pulsed (modulated) and the stream breaks up into a continuous series of drops which are equally
spread and are of the same size.
Surrounding the jet at the point where the drops separate from the liquid stream is a charge
electrode. A voltage is applied between the charge electrode and the drop stream. When the drop
breaks off from the stream it carries a charge proportional to the applied voltage at the instant at
which it breaks off. By varying the charge electrode voltages at the same rate as the drops are
produced, it is possible to charge every drop to a predetermined level.
The drop stream continues its flight and passes between two deflector plates which are maintained
at a constant potential, typically plus and minus 5 kilovolts. In the presence of this field a drop is
deflected towards one of the plates by an amount proportional to the charge carried. Drops which
are uncharged are unelected and are collected by a gutter to be recycled into the ink tank. Those
drops which are charged, and, therefore, deflected, are printed on the substrate, which is travelling
at a certain degree and speed to the direction of the drop deflection.
By varying the charge on the individual drops, whatever pattern is required (including
alphanumeric characters) may be printed. A series of drops deflected across the substrate is known
as a raster.