Valve jet printer with inert plunger tip

Patent metadata

Field	Value
Publication number	US-10059098-B2
Application number	US-201715618866-A
Country	US
Kind code	B2
Filing date	Jun 9, 2017
Priority date	Oct 27, 2010
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A valve jet printer includes a solenoid coil and a plunger rod having a magnetically susceptible shank. A first end of the shank and at least a portion of the shank are received within a bore of the solenoid coil. The printer also includes a nozzle including an orifice extending therethrough and a spring biasing a second end of the shank toward the nozzle. The second end of the plunger rod includes a tip formed of perfluoroelastomer (FFKM). The second end of the shank includes a cup-shaped cavity having a convex bottom and a circular side. The tip includes a concave base and an annular flange. In an assembled state, the concave base of the tip contacts the convex bottom of the cup-shaped cavity, and the end of the circular side opposite the convex bottom is rolled over the annular flange thereby securing the tip in the cup-shaped cavity.

First claim

The invention claimed is:

1. A valve jet printer comprising:
a solenoid coil;
a magnetically susceptible plunger rod, at least a portion of the plunger rod received within a bore of the solenoid coil;
a stop positioned within the bore of the solenoid coil and configured to limit travel of the plunger rod;
a nozzle including an orifice extending therethrough; and
a spring configured to bias the plunger rod toward the nozzle, wherein the plunger rod comprises a tip formed of perfluoroelastomer (FFKM) configured to contact the orifice of the nozzle.

2. The valve j et printer of claim 1 , wherein the plunger rod comprises a shank having a first end and a second end at opposite ends thereof.

3. The valve jet printer of claim 2 , wherein the shank is formed of stainless steel that has been heat-treated to make the shank magnetically susceptible.

4. The valve jet printer of claim 2 , wherein the second end of the shank comprises a cup-shaped cavity having a convex bottom and a circular side, wherein the tip comprises a concave base and an annular flange; and
wherein, in an assembled state of the tip and the second end of the shank, the concave base of the tip contacts the convex bottom of the cup-shaped cavity, and an end of the circular side opposite the convex bottom is rolled into contact with the annular flange, thereby securing the tip in the cup-shaped cavity.

5. The valve jet printer of claim 1 , wherein absent electrical power being supplied to the solenoid coil, the spring is configured to bias the tip into contact with the orifice of the nozzle; and
wherein, in response to the electrical power being supplied to the solenoid coil, the tip is further configured to move away from the orifice of the nozzle against the bias provided by the spring until the plunger rod contacts the stop.

6. The valve jet printer of claim 5 , wherein in response to the spring biasing the tip into contact with the orifice of the nozzle, the tip is further configured to be deformed from its original shape to form a seal with the orifice of the nozzle; and
wherein, in response to the tip moving away from the orifice of the nozzle, the tip is further configured to resume its original shape.

7. The valve jet printer of claim 1 , wherein the tip comprises at least one of the following properties:
a Shore A hardness between 65 and 95;
a tensile strength of approximately 2,000 lb/in 2 ;
a maximum continuous service temperature of approximately 325° C.;
a 50% modulus of 15.5 MPa;
a tensile strength at break of 22.75 MPa;
surface smoothness between 20 and 50 micro inches;
a thickness between 0.3 and 0.6 mm;
an elongation at break of 75%; and
a compression set of 12% for 70 hours at 204° C., or 23% for 70 hours at 260° C.

8. The valve jet printer of claim 1 , wherein the tip comprises perfluoroalkylpolyether in the range between 5-8 wt % and perfluoroelastomer <97 wt %.

9. The valve jet printer of claim 1 , wherein the tip further comprises at least one of:
polyamide fibers at less than 20 wt %;
polytetrafluoroethylene at less than 20 wt %; and
microcrystalline silica at less than 15 wt %.

10. A valve jet printer comprising:
a frame defining an ink cavity;
a plurality of ink jets supported by the frame, each ink jet comprising:
a solenoid coil,
a magnetically susceptible plunger rod, at least a portion of the plunger rod received within a bore of the solenoid coil,
a stop positioned within the bore of the solenoid coil and configured to limit travel of the plunger rod,
a nozzle including an orifice extending therethrough,
a spring configured to bias the plunger rod toward the nozzle, wherein the plunger rod comprises a tip formed of perfluoroelastomer (FFKM) configured to contact the orifice of the nozzle; and

a controller operating under control of a control program for selectively causing electrical power to be supplied to or withheld from each solenoid coil in coordination with movement of a substrate relative to the plurality of ink jets.

11. The valve jet printer of claim 10 , wherein the controller is configured to cause the plurality of ink jets to dispense ink disposed in the ink cavity onto the substrate via the orifices in accordance with instructions programmed into the controller.

12. The valve jet printer of claim 10 , wherein, in response to an absence of electrical power being supplied to the solenoid coil of an ink jet, the spring is configured to bias the tip into sealing contact with the orifice of the nozzle; and
wherein, in response to the electrical power being supplied to the solenoid coil of an ink jet, the tip is further configured to move away from the orifice of the nozzle against the bias provided by the spring until the plunger rod contacts the stop.

13. The valve jet printer of claim 12 , wherein in response to the spring biasing the tip into contact with the orifice of the nozzle, the tip is further configured to be deformed from its original shape to form a seal with the orifice of the nozzle; and
wherein, in response to the tip moving away from the orifice, the tip is further configured to resume its un-deformed shape.

14. The valve jet printer of claim 10 , wherein the plunger rod comprises a shank having a first end and a second end at opposite ends thereof.

15. The valve jet printer of claim 14 , wherein the shank comprises stainless steel that has been heat-treated to make the shank magnetically susceptible.

16. The valve jet printer of claim 14 , wherein the second end of the shank comprises a cup-shaped cavity having a convex bottom and a circular side; and
wherein the tip comprises a concave base and an annular flange, wherein, in an assembled state of the tip and the second end of the shank, the concave base of the tip contacts the convex bottom of the cup-shaped cavity, and an end of the circular side opposite the convex bottom is rolled into contact with the annular flange, thereby securing the tip in the cup-shaped cavity.

17. The valve jet printer of claim 10 , wherein the tip comprises at least one of the following properties:
a Shore A hardness between 65 and 95;
a tensile strength of approximately 2,000 lb/in 2 ;
a maximum continuous service temperature of approximately 325° C.;
a 50% modulus of 15.5 MPa;
a tensile strength at break of 22.75 MPa;
surface smoothness between 20 and 50 micro inches;
a thickness between 0.3 and 0.6 mm;
an elongation at break of 75%; and
a compression set of 12% for 70 hours at 204° C., or 23% for 70 hours at 260° C.

Assignees

• Matthews Int Corp

Inventors

• Wallsten Hans Elon
• Käck Nils Johan Fredrik

Classifications

• B41J2/175

  Ink supply systems {; Circuit parts therefor} · CPC title

• B41J2/04 Primary

  generating single droplets or particles on demand · CPC title

• B41J2/17596

  Ink pumps, ink valves · CPC title

• B41J2202/05

  Heads having a valve · CPC title

• B41J2002/041

  Electromagnetic transducer · CPC title