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An ink jet printer includes a fluid supply system for supplying ink through the print head of the printer. The fluid supply system includes a pump arrangement supplying ink to the print head from a supply tank via a fluid supply line. A plurality of ink return lines are connected between the pump ou

An ink jet printer includes a fluid supply system for supplying ink through the print head of the printer. The fluid supply system includes a pump arrangement supplying ink to the print head from a supply tank via a fluid supply line. A plurality of ink return lines are connected between the pump outlet and the pump inlet. Each of the ink return lines includes a flow restriction, with the flow restriction in each line providing a fluid flow impedance which differs from the impedances provided by the other flow restrictions. A valve arrangement connects the pump outlet to selected ones of the ink return lines, to provide means for controlling the flow rate of ink supplied through the ink supply line to the print head. During periods in which the printer is shut down, a substantially reduced ink flow through the print head is continuously maintained at a reduced fluid flow rate and at a reduced fluid pressure.

대표청구항 ▼

An ink jet printer, comprising: a print head including a fluid receiving reservoir, and an orifice plate defining at least one orifice communicating with said reservoir for providing ink flow through said orifice to form a jet drop stream for printing, fluid supply means, including an ink supply tan

An ink jet printer, comprising: a print head including a fluid receiving reservoir, and an orifice plate defining at least one orifice communicating with said reservoir for providing ink flow through said orifice to form a jet drop stream for printing, fluid supply means, including an ink supply tank, and pump means connected to said ink supply tank, print head supply line means for providing flow of ink from said fluid supply means to said fluid receiving reservoir of said print head, print head return line means for returning ink from said fluid receiving reservoir of said print head to said fluid supply means, and control means for controlling the flow of ink supplied to said print head by said fluid supply means to provide a flow of ink at a predetermined flow rate during printing and to provide a substantially reduced continuous flow of ink from said print head supply line means to said print head return line means through said reservoir at substantially reduced fluid pressure during periods in which said printer is shut down and a jet drop stream is not produced by said print head, whereby ink is continuously circulated through said print head without weeping of ink through said orifice, drying of ink adjacent said orifice or deposit of contaminants within said reservoir.