# US 7,607,766 B2 · Method and print head for flow conditioning a fluid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,766 B2 - Document ID: US7607766B2 - Status: Granted - Kind: B2 - Application number: 11/568,229 - Filed: 2005-05-04 - Published: 2007-10-04 - Granted: 2009-10-27 - Earliest claimed: 2004-05-04 - Assignees: Kodak Graphic Communications Canada Company - Inventors: Thomas W. Steiner - Web page: https://patentgrep.com/patent/US7607766B2 ## CPC - B41J 2/02: generating a continuous ink jet - B41J 2/025: by vibration - B41J 2/09: Deflection means - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract A continuous inkjet print head jets a plurality of fluid streams from an array of multiple nozzle channels. The print head includes a flow conditioning means that establishes fully developed flow in one or more regions of the print head such that substantially equal flow conditions are created at each of the inlets of the multiple nozzle channels. The substantially equal flow conditions reduce nozzle-to-nozzle variations with respect to the required trajectories of the jetted fluids to improve jet pointing and thus lead to better print quality. ## Claims ### Claim 1 A method for jetting at least one continuous stream of fluid from at least one nozzle channel of a multi-channel print head, the method comprising: establishing substantially fully developed flow in at least one first region of a fluid in the print-head; jetting the fluid in at least a portion of the at least one first region from the at least one nozzle channel; and wherein fully developed flow comprises a bounded flow in a conduit having the characteristics of an unchanging velocity profile within the conduit, where the wall shear is at least approximately constant and the pressure drops at least approximately linearly with distance along the axial length of the conduit. ### Claim 2 (depends on 1) The method of claim 1, wherein the at least one nozzle channel comprises a plurality of nozzle channels, each nozzle channel comprising an inlet and wherein the method comprises establishing substantially equal flow conditions at each of the inlets. ### Claim 3 (depends on 1) The method of claim 1, wherein the at least one nozzle channel comprises an inlet and the at least one first region is proximate to the inlet. ### Claim 4 (depends on 1) The method of claim 1, comprising establishing substantially fully developed flow in a plurality of first regions of the fluid in the print head wherein the plurality of first regions have substantially equal flow conditions. ### Claim 5 (depends on 1) The method of claim 1, wherein the substantially fully developed flow is established by a first flow conditioning means. ### Claim 6 (depends on 5) The method of claim 5, wherein the first flow conditioning means establishes substantially fully developed laminar flow in the at least one first region. ### Claim 7 (depends on 5) The method of claim 5, wherein the first flow conditioning means comprises at least one conduit, an axial length of the at least one conduit being equal to or greater than an entrance length associated with the at least one conduit, and wherein the method further comprises establishing substantially fully developed flow within the at least one conduit. ### Claim 8 (depends on 7) The method of claim 7, wherein the axial length of the at least one conduit is sized to establish substantially fully developed laminar flow within the at least one conduit. ### Claim 9 (depends on 7) The method of claim 7, comprising establishing a first volume flow rate of the fluid through the at least one conduit and a second volume flow rate of the fluid through the at least one nozzle channel, wherein the first and second volume flow rates are equal. ### Claim 10 (depends on 5) The method of claim 5, comprising: establishing a second flow in at least one second region of the fluid in the print head; and jetting the fluid in at least a portion of the at least one second region from at least one additional nozzle channel. ### Claim 11 (depends on 10) The method of claim 10, wherein the at least one additional nozzle channel comprises a plurality of additional nozzle channels, each additional nozzle channel comprising an additional inlet and wherein the method comprises establishing substantially equal flow conditions at each of the additional inlets. ### Claim 12 (depends on 10) The method of claim 10, wherein the at least one additional nozzle channel comprises an inlet and the at least one second region is proximate to the inlet. ### Claim 13 (depends on 10) The method of claim 10, comprising establishing second flows in a plurality of second regions of the fluid in the print head, wherein the plurality of second regions have substantially equal flow conditions. ### Claim 14 (depends on 10) The method of claim 10, wherein the second flow comprises substantially frilly developed flow. ### Claim 15 (depends on 14) The method of claim 14, wherein the second flow is established to be substantially fully developed by a second conditioning means. ### Claim 16 (depends on 14) The method of claim 14, wherein the second flow comprises substantially fully developed laminar flow. ### Claim 17 A multi-channel print head for jetting at least one continuous stream of fluid, the print head comprising: at least one first flow conditioning means operable for establishing substantially fully developed flow in at least one first region of a fluid in the print head; and at least one nozzle channel in fluid communication with the at least one first region, the at least one nozzle channel operable for jetting the at least one continuous stream from at least a portion of the at least one first region; comprising a fluid accumulator, wherein the fluid accumulator is positioned between the at least one first flow conditioning means and the at least one nozzle channel. ### Claim 18 (depends on 17) The print bead of claim 17, wherein the at least one nozzle channel comprises a plurality of nozzle channels, each nozzle channel comprising an inlet, and the at least one first flow conditioning means is operable for establishing substantially equal flow conditions at each of the inlets. ### Claim 19 (depends on 17) The print head of claim 17, wherein the at least one nozzle channel comprises an inlet and the first at least one first region is proximate to the inlet. ### Claim 20 (depends on 17) The print head of claim 17, wherein the at least one first region comprises a plurality of first regions and the at least one first flow conditioning means is operable for establishing substantially equal flow conditions in the plurality of first regions. ### Claim 21 (depends on 17) The print head of claim 17, wherein the at least one first flow conditioning means is operable for establishing substantially fully developed laminar flow in the at least one first region. ### Claim 22 A multi-channel print head for jetting at least one continuous stream of fluid, the print head comprising: at least one first flow conditioning means operable for establishing substantially filly developed flow in at least one first region of a fluid in the print head; and at least one nozzle channel in fluid communication with the at least one first region, the at least one nozzle channel operable for jetting the at least one continuous stream from at least a portion of the at least one first region; wherein the at least one first flow conditioning means comprises a least one backside tunnel, the at least one backside tunnel being operable for establishing the substantially fully developed flow in the at least one first region. ### Claim 23 (depends on 22) The print head of claim 22, wherein the at least one backside tunnel comprises an axial length equal to or greater than an entrance length associated with the at least one backside tunnel. ### Claim 24 (depends on 23) The print head of claim 23, wherein the at least one backside tunnel is in direct fluid communication with the at least one nozzle channel. ### Claim 25 (depends on 22) The print head of claim 22, wherein at least one of: the at least one nozzle channel and the at least one backside tunnel is fabricated by micro-machining. ### Claim 26 (depends on 25) The print head of claim 25, wherein the at least one backside tunnel and the at least one nozzle channel are fabricated in a monolithic component. ### Claim 27 A multi-channel print head for jetting at least one continuous stream of fluid, the print head comprising: at least one first flow conditioning means operable for establishing substantially fully developed flow in at least one first region of a fluid in the print head; and at least one nozzle channel in fluid communication with the at least one first region, the at least one nozzle channel operable for jetting the at least one continuous stream from at least a portion of the at least one first region; wherein the at least one first flow conditioning means comprises a flow conditioning plate, the flow conditioning plate comprising at least one flow conditioning bore operable for establishing the substantially fully developed flow in the at least one first region. ### Claim 28 (depends on 27) The print head of claim 27, wherein the at least one flow conditioning bore comprises an axial length equal to or greater than an entrance length associated with the at least one flow conditioning bore. ### Claim 29 (depends on 28) The print head of claim 28, wherein the at least one flow conditioning bore comprises a plurality of flow conditioning bores and a number of the flow conditioning bores is greater than a number of the at least one nozzle channel. ### Claim 30 (depends on 27) The print head of claim 27, wherein the at least one flow conditioning bore comprises a first cross-sectional area, the at least one nozzle channel comprises a second cross-sectional area and the first cross-sectional area is smaller than the second cross-sectional area. ### Claim 31 (depends on 30) The print head of claim 30, wherein the flow conditioning plate is a filter means. ### Claim 32 (depends on 27) The print head of claim 27, comprising a fluid accumulator positioned between the flow conditioning plate and the at least one nozzle channel. ### Claim 33 (depends on 27) The print head of claim 27, wherein the flow conditioning plate is fabricated by micro-machining. ### Claim 34 (depends on 27) The print head of claim 27, wherein the at least one nozzle channel is the flow conditioning means. ### Claim 35 (depends on 34) The print head of claim 34, wherein the at least one nozzle channel comprises an axial length equal to or greater than an entrance length associated with the at least one nozzle channel. ### Claim 36 (depends on 27) The print head of claim 27, further comprising: at least one second conditioning means operable for establishing a second flow in at least one second region of the fluid in the print head; and at least one additional nozzle channel of the multi-channel print head in fluid communication with the at least one second region, the at least one additional nozzle channel operable for jetting at least one additional continuous stream of the fluid from at least a portion of the at least one second region. ### Claim 37 (depends on 36) The print head of claim 36, wherein the at least one additional nozzle channel comprises a plurality of additional nozzle channels, each additional nozzle channel comprising an additional inlet, and the at least one second conditioning means is operable for establishing substantially equal flow conditions at each of the additional inlets. ### Claim 38 (depends on 36) The print head of claim 36, wherein the at least one additional nozzle channel comprises an additional inlet and the at least a second region is proximate to the additional inlet. ### Claim 39 (depends on 36) The print head of claim 36, wherein the at least one second region comprises a plurality of second regions and the at least one second conditioning means is operable for establishing substantially equal flow conditions in the plurality of second regions. ### Claim 40 (depends on 39) The print head of claim 39, wherein the flow conditions in the at least one first region are different than the flow conditions in the at least one second region. ### Claim 41 (depends on 36) The print head of claim 36, wherein the second flow comprises substantially hilly developed flow. ### Claim 42 A multi-channel print head for jetting at least one continuous stream of fluid, the print head comprising: at least one first flow conditioning means operable for establishing substantially fully developed flow in at least one first region of a fluid in the print head; and at least one nozzle channel in fluid communication with the at least one first region, the at least one nozzle channel operable for jetting the at least one continuous stream from at least a portion of the at least one first region; at least one second conditioning means operable for establishing a second flow in at least one second region of the fluid in the print head; and at least one additional nozzle channel of the multi-channel print head in fluid communication with the at least one second region, the at least one additional nozzle channel operable for jetting at least one additional continuous stream of the fluid from at least a portion of the at least one second region wherein the second flow comprises substantially fully developed flow; wherein at least one of the first flow conditioning means and the second conditioning means comprises at least one of: a back side tunnel and a flow conditioning plate.