Ink return system for a multijet ink jet printer

Claim 2

In an electrostatically deflected ink-jet printer providing a continuous spray of ink droplets, a method for controlling the interception of said ink droplets with a printing medium comprising the steps of; a. providing deflection plates at a non-zero potential for generating an electrostatic field, each plate including a catch-chamber, b. imparting an electric charge to only those droplets which are to intercept said printing medium, c. directing the uncharged droplets to a catch-chamber d. breaking the ink received by the catch-chamber into drops to thereby cause the ink to form a high impedance return path to the deflection plates, e. passing each drop over a ground plate whereby the charge acquired by the ink upon passing through the catch-chambers of the deflection plates is neutralized and f. collecting the neutralized drops of ink in a reservoir.

Claim 3

The method of claim 1 further including the step of disposing said deflection plates at a slight angle with respect to the trajectory of the uncharged droplets.

Claim 4

In an electrostatically deflected ink-jet printer of the type including at least one nozzle for ejecting ink toward a printing medium, a charging electrode for selectively charging ink droplets, and an electrostatic field for deflecting the ink droplets from their trajectory an amount proportional to the charge thereon, the improvement comprising: a. electrostatic deflection plate having a non-zero potential thereon for generating said electrostatic field, each of said deflection plates including a catch-chamber for intercepting and collecting substantially uncharged droplets, said collected droplets thereby assuming a charge dependent upon the potential of said plate, b. a reservoir, held at substantially zero potential, for storing said ink to be fed through said at least one nozzle, and c. a return conduit system for returning the said ink collected by said catch-chambers to saiD reservoir, said return conduit system comprising, i. a container means, receiving said collected ink in a substantially continuous flow, for emitting said received collected ink in separate and discrete droplets which are relatively large compared to said ink droplets collected by said catch-chamber, to thereby result in a relatively large electrical impedance path through said ink in said return conduit system between said catch-chamber and said reservoir, and ii. means insulating said container means from said reservoir.

Claim 5

In an electrostatically deflected ink-jet printer of the type including at least one nozzle for ejecting ink toward a printing medium, a charging electrode for selectively charging ink droplets, and an electrostatic field for deflecting the ink droplets from their trajectory an amount proportional to the charge thereon, the improvement comprising: a. electrostatic deflection plate having a non-zero potential thereon for generating said electrostatic field, each of said deflection plates including a catch-chamber for intercepting and collecting substantially uncharged droplets, said collected droplets thereby assuming a charge dependent upon the potential of said plate, b. a reservoir, held at substantially zero potential, for storing said ink to be fed through said at least one nozzle, and c. a return conduit system for returning the said ink collected by said catch-chambers to saiD reservoir, said return conduit system comprising, i. a container means, receiving said collected ink in a substantially continuous flow, for emitting said received collected ink in separate and discrete droplets which are relatively large compared to said ink droplets collected by said catch-chamber, to thereby result in a relatively large electrical impedance path through said ink in said return conduit system between said catch-chamber and said reservoir, and ii. means insulating said container means from said reservoir.

Claim 6

The ink-jet printer of claim 3 wherein said deflection plates are disposed at a slight angle with resepect to the trajectory of said substantially uncharged droplets.

Claim 7

The ink jet printer of claim 3 wherein there are a plurality of nozzles, a pair of said deflection plates being associated with each nozzle, each deflection plate being either at a positive or negative potential with respect to ground, said conduit system comprising a first conduit coupled to the catch chambers of said negative potential deflection plates and a second conduit coupled to the catch chambers of said positive potential deflection plates, further including first and second of said containers for receiving ink from said conduit system, said first container receiving ink from said first conduit said second container receiving ink from said second conduit.

Claim 8

The ink jet printer of claim 5 wherein at least one plate of each pair of deflection plates associated with a nozzle forms one plate of another pair of deflection plates associated with another nozzle.

Claim 9

The ink-jet printer of claim 3 wherein each of said deflection plates is hollow, the hollow portion of the deflection plate forming the catch-chamber.

Claim 10

In an electrostatically deflected ink-jet printer of the type including at least one nozzle for ejecting ink toward a printing medium, a charging electrode for selectively charging ink droplets, and an electrostatic field for deflecting the ink droplets from their trajectory an amount proportional to the charge thereon, the improvement comprising: a. electrostatic deflection plates having a non-zero potential thereon for generating said electrostatic field, each of said deflection plates being provided with a catch-chamber for intercepting substantially uncharged droplets; b. an ink return conduit system receiving the ink collected by said catch-chamber, c. a container for receiving ink from said conduit system in a substantially continuous flow, said container comprising a compartment including means for collecting the received ink and emitting it in the form of drops, so that the ink forms a high impedance return path to said deflection plates, said container further comprising another compartment including a grounded conductive plate for receiving said ink drops whereby the charge on the ink drops acquired upon passing through the catch-chambers of the deflection plates is neutralized, and d. an ink collecting reservoir for receiving the ink drops after they pass through said container.

Claim 11

In an electrostatically deflected ink-jet printer of the type including at least one nozzle for ejecting ink toward a printing medium, a charging electrode for selectively charging ink droplets, and an electrostatic field for deflecting the ink droplets from their trajectory an amount proportional to the charge thereon, the improvement comprising: a. electrostatic deflection plates having a non-zero potential thereon for generating said electrostatic field, each of said deflection plates being provided with a catch-chamber for intercepting substantially uncharged droplets; b. an ink return conduit system receiving the ink collected by said catch-chamber, c. a container for receiving ink from said conduit system in a substantially continuous flow, said container comprising a compartment including means for collecting the received ink and emitting it in the form of drops, so that the ink forms a high impedance return path to said deflection plates, said container further comprising another compartment including a grounded conductive plate for receiving said ink drops whereby the charge on the ink drops acquired upon passing through the catch-chambers of the deflection plates is neutralized, and d. an ink collecting reservoir for receiving the ink drops after they pass through said container.

Claim 12

The ink-jet printer of claim 8 wherein said container is formed from non-conductive materials and wherein said compartment includes high surface tension material and said another compartment includes an inlet port for receiving dry air and an outlet port coupled to said reservoir.

Claim 13

The ink jet printer of claim 9 wherein said reservoir includes an air outlet port for connection to subatmospheric pressure and an ink outlet port for returning ink to said nozzle.