Pigment dispersal in an ink jet printer
AssigneeLinx Printing Technologies Limited
InventorsGraham Thomas, Bryn Jones
Life of this patent
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Abstract
In a continuous ink jet printer for use with pigmented ink, the entrance to the ink path (81), (35) from the interior of the ink tank (27) to the ink pump (31) is made up of a plurality of small inlet openings, which may be provided by nozzles 85 formed in a shroud 83 that fits around an ink filter (33) in the ink tank (27). The openings are provided at the bottom of the ink tank (27), close to the floor, and face parallel to the floor or at least partially towards it. If the ink pump (31) is driven in reverse, any ink in the ink path is driven at speed out through the inlet openings into the interior of the ink tank (27), followed by air. This tends to disperse pigment that may have settled to the bottom on the ink tank (27).
Claims20
A continuous ink jet printer comprising an ink circuit, the ink circuit comprising an ink tank, an ink pump arrangement, an ink supply path from one or more ink inlet openings inside the ink tank to the ink pump arrangement and an ink return path from the ink pump arrangement to the interior of the ink tank,
- the printer further comprising a control system arranged (a) to control the ink pump arrangement to pump ink around the ink circuit in a forward direction, in which the ink flows from the interior of the ink tank through the one or more ink inlet openings and along the ink supply path to the ink pump arrangement, and from the ink pump arrangement along the ink return path back to the interior of the ink tank, and (b) to control the ink pump arrangement to pump fluid around the ink circuit in a reverse direction, in which the fluid flows from the interior of the ink tank along the ink return path to the ink pump arrangement, and from the ink pump arrangement along the ink supply path and through the one or more ink inlet openings back to the interior of the ink tank.
A method of operating a continuous ink jet printer, the printer comprising an ink circuit, the ink circuit comprising an ink tank, an ink pump arrangement, an ink supply path from one or more ink inlet openings inside the ink tank to the ink pump arrangement and an ink return path from the ink pump arrangement to the interior of the ink tank, the method comprising:
- (a) a forward flow step in which the ink pump arrangement is used to pump ink around the ink circuit in a forward direction such that ink flows from the interior of the ink tank through the one or more ink inlet openings and along the ink supply path to the ink pump arrangement, and from the ink pump arrangement along the ink return path back to the interior of the ink tank;
- and
- (b) a reverse flow step in which the ink pump arrangement is used to pump fluid around the ink circuit in a reverse direction such that fluid flows from the interior of the ink tank to the ink pump arrangement along the ink return path, and from the ink pump arrangement back to the interior of the ink tank along the ink supply path and through the one or more ink inlet openings.
Dependencies are inferred from the claim text.