# US 10,864,724 B2 · Valve jet printer with inert plunger tip > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,864,724 B2 - Document ID: US10864724B2 - Status: Granted - Kind: B2 - Application number: 16/741,054 - Filed: 2020-01-13 - Published: 2020-07-09 - Granted: 2020-12-15 - Earliest claimed: 2010-10-27 - Assignees: Matthews International Corporation - Applicants: Matthews International Corporation - Inventors: Hans Elon Wallsten; Nils Johan Fredrik Käck - Web page: https://patentgrep.com/patent/US10864724B2 ## CPC - B41J 2/14: Structure thereof {only for on-demand ink jet heads} - B05B 13/002: {Machines or plants for applying coating liquids or other fluent materials by inkjet} - B41J 2/04: generating single droplets or particles on demand - B41J 2/175: Ink supply systems {; Circuit parts therefor} - B41J 2/17596: {Ink pumps, ink valves} - B41J 2002/041: {Electromagnetic transducer} - B41J 2202/05: Heads having a valve - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D) ## 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. ## Claims ### Claim 1 A plunger rod for dispensing ink in a valve jet printer, the plunger rod comprising: a shank having a first end and a second end at opposite ends thereof; and a tip comprising a resilient, chemically inert material arranged at the second end. ### Claim 2 (depends on 1) The plunger rod of claim 1, wherein the resilient, chemically inert material is a perfluoroelastomer. ### Claim 3 (depends on 2) The plunger rod of claim 2, wherein the tip comprises: perfluoroalkylpolyether in the range between about 5 wt % to about 8 wt %; and less than 95 wt % perfluoroelastomer. ### Claim 4 (depends on 1) The plunger rod of claim 1, wherein the tip further comprises one or more of polyamide fibers, polytetrafluoroethylene, and microcrystalline silica. ### Claim 5 (depends on 1) The plunger rod of claim 1, wherein the tip further comprises one or more of the following: less than 20 wt % polyamide fibers; less than 20 wt % polytetrafluoroethylene; and less than 15 wt % microcrystalline silica. ### Claim 6 (depends on 1) The plunger rod of claim 1, wherein the tip is configured to contact and form a seal with a nozzle of the valve jet printer. ### Claim 7 (depends on 6) The plunger rod of claim 6, wherein: in response to a spring biasing the tip into contact with an orifice of the nozzle, the tip is configured to be deformed from its original shape to form a seal with the orifice of the nozzle; and in response to the tip moving away from the orifice of the nozzle, the tip is configured to resume its original shape. ### Claim 8 (depends on 1) The plunger rod of claim 1, wherein the shank is magnetically susceptible. ### Claim 9 (depends on 1) The plunger rod of claim 1, wherein the tip has one or more of the following properties: a Shore A hardness between 65 and 95; a tensile strength of approximately 2,000 lb/in2; 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; an elongation at break of 75%; and a compression set of 12% for 70 hours at 204° C., or 23% at 70 hours at 260° C. ### Claim 10 (depends on 1) The plunger rod of claim 1, wherein the second end of the shank comprises a cup-shaped cavity having a convex bottom and a circular side. ### Claim 11 (depends on 1) The plunger rod of claim 1, wherein the tip comprises a concave base and an annular flange configured to contact the second end of the shank. ### Claim 12 A plunger rod for dispensing ink in a valve jet printer, the plunger rod comprising: a shank having a first end and a second end at opposite ends thereof; and a tip comprising a concave base and an annular flange configured to contact the second end of the shank. ### Claim 13 (depends on 12) The plunger rod of claim 12, wherein the second end of the shank comprises a cup-shaped cavity having a convex bottom and a circular side, 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 contacts the annular flange, thereby securing the tip in the cup-shaped cavity. ### Claim 14 (depends on 12) The plunger rod of claim 12, wherein the tip is configured to contact and form a seal with a nozzle of the valve jet printer. ### Claim 15 (depends on 14) The plunger rod of claim 14, wherein: in response to a spring biasing the tip into contact with an orifice of the nozzle, the tip is configured to be deformed from its original shape to form a seal with the orifice of the nozzle; and in response to the tip moving away from the orifice of the nozzle, the tip is configured to resume its original shape. ### Claim 16 (depends on 12) The plunger rod of claim 12, wherein the shank is magnetically susceptible. ### Claim 17 (depends on 12) The plunger rod of claim 12, wherein the tip has one or more of the following properties: a Shore A hardness between 65 and 95; a tensile strength of approximately 2,000 lb/int; 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; an elongation at break of 75%; and a compression set of 12% for 70 hours at 204° C., or 23% at 70 hours at 260° C. ### Claim 18 (depends on 12) The plunger rod of claim 12, wherein the tip comprises a resilient, chemically inert material. ### Claim 19 (depends on 18) The plunger rod of claim 18, wherein the resilient, chemically inert material is a perfluoroelastomer. ### Claim 20 (depends on 19) The plunger rod of claim 19, wherein the tip comprises: perfluoroalkylpolyether in the range between about 5 wt % to about 8 wt %; and less than 95 wt % perfluoroelastomer. ### Claim 21 (depends on 18) The plunger rod of claim 18, wherein the tip further comprises one or more of polyamide fibers, polytetrafluoroethylene, and microcrystalline silica. ### Claim 22 (depends on 18) The plunger rod of claim 18, wherein the tip further comprises one or more of the following: less than 20 wt % polyamide fibers; less than 20 wt % polytetrafluoroethylene; and less than 15 wt % microcrystalline silica.