# US 11,027,544 B2 · Ink jet method and ink jet apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,027,544 B2 - Document ID: US11027544B2 - Status: Granted - Kind: B2 - Application number: 16/784,600 - Filed: 2020-02-07 - Published: 2020-08-13 - Granted: 2021-06-08 - Earliest claimed: 2019-02-08 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Keitaro Nakano; Kyohei Tanaka; Midori Sekine; Chigusa Sato - Web page: https://patentgrep.com/patent/US11027544B2 ## CPC - C09D 11/101: Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing - B41J 2/135: Nozzles - B41J 2/435: characterised by selective application of radiation to a printing material or impression-transfer material - B41J 11/00214: {using UV radiation} - C09D 11/30: Inkjet printing inks - C09D 11/322: Pigment inks - B41M 7/0081: {using electromagnetic radiation or waves, e.g. ultraviolet radiation, electron beams} - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P) ## Abstract An ink jet method includes: a discharging step of discharging a radiation-curable ink jet composition onto a recording medium at an ink weight per dot of 22 ng/dot or less by using an ink jet head configured to discharge the radiation-curable ink jet composition and having a nozzle density of 600 npi or more; and an irradiating step of irradiating, with radiation, the radiation-curable ink jet composition attached to the recording medium. The radiation-curable ink jet composition contains polymerizable compounds including a monofunctional monomer and a multifunctional monomer. The monofunctional monomer includes a nitrogen-containing monofunctional monomer. The amount of the monofunctional monomer is 90 mass % or more relative to the total amount of the polymerizable compounds. The amount of the nitrogen-containing monofunctional monomer is from 1 to 15 mass % relative to the total amount of the polymerizable compounds. ## Claims ### Claim 1 An ink jet method comprising: a discharging step of discharging a radiation-curable ink jet composition from an ink jet head; and an irradiating step of irradiating the discharged radiation-curable ink jet composition with radiation, wherein the ink jet head includes a first nozzle group including a plurality of nozzles in a column direction and a second nozzle group including a plurality of nozzles in the column direction, and the first nozzle group and the second nozzle group are arranged at different positions from each other in the column direction and in a scanning direction intersecting the column direction, in the discharging step, a scan that involves discharging the radiation-curable ink jet composition from the first nozzle group and the second nozzle group while the ink jet head is scanned in the scanning direction is performed, in the irradiating step, the radiation is emitted from a radiation source disposed at a side of the ink jet head opposite to the scanning direction, the radiation-curable ink jet composition contains a monofunctional monomer including a nitrogen-containing monofunctional monomer, an amount of the monofunctional monomer being 80 mass % or more relative to a total amount of the radiation-curable ink jet composition, and an amount of the nitrogen-containing monofunctional monomer is from 5 to 20 mass % relative to the total amount of the radiation-curable ink jet composition. ### Claim 2 (depends on 1) The ink jet method according to claim 1, wherein the discharging step involves discharging the radiation-curable ink jet composition from the ink jet head while a carriage carrying the ink jet head and the radiation source disposed at a side of the ink jet head opposite to the scanning direction is scanned in the scanning direction, the irradiating step involves irradiating the radiation-curable ink jet composition discharged in the scanning with radiation from the radiation source in the same scanning as in the discharging step, and the scanning is performed a plurality of times. ### Claim 3 (depends on 1) The ink jet method according to according to claim 1, wherein the nitrogen-containing monofunctional monomer includes either a monofunctional monomer having a nitrogen-containing heterocyclic ring or a monofunctional monomer having a cyclic amide structure. ### Claim 4 (depends on 1) The ink jet method according to claim 1, wherein the nitrogen-containing monofunctional monomer includes acryloylmorpholine. ### Claim 5 (depends on 1) The ink jet method according to claim 1, wherein an amount of the monofunctional monomer 80 to 95 mass % relative to the total amount of the radiation-curable ink jet composition. ### Claim 6 (depends on 1) The ink jet method according to claim 1, wherein the radiation-curable ink jet composition contains a bi- or higher-functional polymerizable compound, and an amount of the bi- or higher-functional polymerizable compound is 20 mass % or less relative to the total amount of the radiation-curable ink jet composition. ### Claim 7 (depends on 1) The ink jet method according to claim 1, wherein the amount of the nitrogen-containing monofunctional monomer is from 7 to 20 mass % relative to the total amount of the radiation-curable ink jet composition. ### Claim 8 (depends on 1) The ink jet method according to claim 1, wherein a radiation energy in one time of irradiation during the irradiation is from 50 to 300 J/cm2. ### Claim 9 (depends on 1) The ink jet method according to claim 1, wherein the radiation is ultraviolet radiation having an emission peak wavelength of from 360 to 420 nm. ### Claim 10 (depends on 1) The ink jet method according to claim 1, wherein a distance in the scanning direction between the first nozzle group and the second nozzle group is from 10 to 30 mm. ### Claim 11 (depends on 1) The ink jet method according to claim 1, wherein main curing is performed by one time of irradiation during the irradiation. ### Claim 12 (depends on 1) The ink jet method according to claim 1, wherein the radiation-curable ink jet composition contains, as the monofunctional monomer, either a monofunctional monomer having an aromatic ring or a monofunctional monomer having an alicyclic ring. ### Claim 13 (depends on 1) The ink jet method according to claim 1, wherein an ink weight per dot discharged in the discharging step is 20 ng/dot or less. ### Claim 14 (depends on 1) The ink jet method according to claim 1, wherein the first nozzle group and the second nozzle group each have a nozzle density of from 150 to 600 npi in the column direction. ### Claim 15 (depends on 1) The ink jet method according to claim 1, wherein the first nozzle group and the second nozzle group each have a length of from 1 to 5 inches in the column direction. ### Claim 16 (depends on 1) The ink jet method according to claim 1, wherein the ink jet method is a recording method for performing recording on a recording medium, the discharging step involves attaching the discharged radiation-curable ink jet composition to the recording medium, and the irradiating step involves irradiating, with the radiation, the radiation-curable ink jet composition attached to the recording medium. ### Claim 17 An ink jet apparatus comprising: an ink jet head that discharges a radiation-curable ink jet composition; and a radiation source that emits radiation to the discharged radiation-curable ink jet composition, wherein the ink jet head includes a first nozzle group including a plurality of nozzles in a column direction and a second nozzle group including a plurality of nozzles in the column direction, and the first nozzle group and the second nozzle group are arranged at different positions from each other in the column direction and in a scanning direction intersecting the column direction, the radiation source is disposed at a side of the ink jet head opposite to the scanning direction when the ink jet head is scanned in the scanning direction, the discharged radiation-curable ink jet composition contains a monofunctional monomer including a nitrogen-containing monofunctional monomer, an amount of the monofunctional monomer being 80 mass % of more relative to a total amount of the radiation-curable ink jet composition, and an amount of the nitrogen-containing monofunctional monomer is from 5 to 20 mass % relative to the total amount of the radiation-curable ink jet composition. ### Claim 18 An ink jet head used to discharge a radiation-curable ink jet composition, the ink jet head comprising: a first nozzle group including a plurality of nozzles in a column direction; and a second nozzle group including a plurality of nozzles in the column direction, the first nozzle group and the second nozzle group being arranged at different positions from each other in the column direction and in a scanning direction intersecting the column direction, wherein the radiation-curable ink jet composition to be discharged contains a monofunctional monomer including a nitrogen-containing monofunctional monomer, an amount of the monofunctional monomer being 80 mass % or more relative to a total amount of the radiation-curable ink jet composition, and an amount of the nitrogen-containing monofunctional monomer is from 5 to 20 mass % relative to the total amount of the radiation-curable ink jet composition. ### Claim 19 A set comprising a radiation-curable ink jet composition and an ink jet head, wherein the ink jet head is used to discharge the radiation-curable ink jet composition, the ink jet head includes a first nozzle group including a plurality of nozzles in a column direction and a second nozzle group including a plurality of nozzles in the column direction, and the first nozzle group and the second nozzle group are arranged at different positions from each other in the column direction and in a scanning direction intersecting the column direction, the radiation-curable ink jet composition contains a monofunctional monomer including a nitrogen-containing monofunctional monomer, an amount of the monofunctional monomer being 80 mass % or more relative to a total amount of the radiation-curable ink jet composition, and an amount of the nitrogen-containing monofunctional monomer is from 5 to 20 mass % relative to the total amount of the radiation-curable ink jet composition. ### Claim 20 (depends on 1) The ink jet method according to claim 1, wherein the radiation-curable ink jet composition includes isobornyl acrylate. ### Claim 21 (depends on 1) The ink jet method according to claim 1, wherein the a number of nozzle groups discharging the radiation-curable ink jet composition including the first nozzle group and the second nozzle group is 2 to 4. ### Claim 22 (depends on 1) The ink jet method according to claim 1, wherein an irradiance of the radiation directed toward the radiation-curable ink jet composition during the irradiating is 3 to 12 W/cm2.