US 12,233,646 B2Granted

Continuous ink jet printer and print head assembly therefor

AssigneeLinx Printing Technologies Limited

InventorStephen John Cooke

Life of this patent

Estimating the term…

Loading patent…

Abstract

The print head cover (83) of an electrostatic deflection inkjet printer is made of a material having an electrical surface resistivity of no more than 1012 ohms per square or an electrical volume resistivity of no more than 109 ohm metres and is electrically connected to an earth line (93, 97). This prevents build-up of electric charge on the cover (83). The resistance from the surface of the cover (83) to a place where a cover earth line (93) joins a signal earth line (97) or enters the umbilical (7) is at least 16000 times the resistance from that place to earth. This prevents an electrostatic discharge to the cover (83) disrupting the electronic circuits. The high resistance earth connection for the cover (83) avoids the need for an earthing wire braid in the umbilical (7). The cover (83) may be moulded from an antistatic or static dissipative material.

Claims20

Dependent claims

An electrostatic deflection continuous ink jet printer comprising:

a printer body, a print head and a flexible conduit extending between the printer body and the print head,
the print head comprising (a) an ink gun for forming a continuous ink jet, (b) an arrangement of electrodes to trap electric charges on ink drops of the ink jet and to create an electrostatic field to deflect ink drops carrying trapped electric charges, (c) a gutter for receiving ink drops of the ink jet that are not used for printing and (d) a print head cover that extends over at least a part of a volume in which the ink drops travel in operation of the printer, the print head cover having an exit hole to enable ink drops that are used for printing to exit the said volume, wherein the print head cover is made entirely or mostly from a mouldable polymeric material,
the printer comprising (e) a cover earth line extending from the print head cover,
at least a part of the print head cover having an electrical surface resistivity of no more than 1012 ohms per square or an electrical volume resistivity of no more than 109 ohm.metres, the said at least a part of the print head cover surrounding the exit hole and being electrically connected to the cover earth line.

1 more element

A print head assembly for an electrostatic deflection continuous ink jet printer, the print head assembly comprising:

a print head and a flexible conduit attached to and extending away from the print head,
the print head comprising (a) an ink gun for forming a continuous ink jet, (b) an arrangement of electrodes to trap electric charges on ink drops of the ink jet and to create an electrostatic field to deflect ink drops carrying trapped electric charges, (c) a gutter for receiving ink drops of the ink jet that are not used for printing and (d) a print head cover that extends over at least a part of a volume in which the ink drops travel in operation of the printer, the print head cover having an exit hole to enable ink drops that are used for printing to exit the said volume, wherein the print head cover is made entirely or mostly from a mouldable polymeric material,
the print head assembly comprising (e) a cover earth line extending from the print head cover,
at least a part of the print head cover having an electrical surface resistivity of no more than 1012 ohms per square or an electrical volume resistivity of no more than 109 ohm.metres, the said at least a part of the print head cover surrounding the exit hole and being electrically connected to the cover earth line.

1 more element

Dependencies are inferred from the claim text.