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(11) | EP 0 709 198 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Reversed polarity ink jet imaging |
| (57) A continuous ink jet system includes a linear array of orifices fluidically connected
to a fluid supply and pressurization means to produce a linear array of jets, means
for stimulating the jets for regular break-up of the jet into a plurality of uniform
streams of drops, charging means consisting of a linear array of planar conducting
elements disposed along the path of motion of the jets, one for each jet, such that
placing a preselected voltage on one of the plurality of conducting elements causes
an electrostatic charge to be induced on the corresponding jet, the electrostatic
charge and the placement of the electrode being such that a charge drop receives a
force impulse from the presence of the conducting elements, catcher means disposed
to catch selected drops with predetermined charge from the charging system, return
fluidic means disposed so that drops intercepted by the catcher can be returned through
the fluidic system for eventual re-use in forming the jets, means for moving a substrate
beneath the catcher means so that drops not intercepted by the catcher means are allowed
to impact the substrate to cause printing. The invention provides the improvement
of reversing the polarity of the charging means so as to create drops with positive
charge. |