# US 5,700,314 A · Image forming method, and ink set and ink-jet machinery used therein > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,314 A - Document ID: US5700314A - Status: Granted - Kind: A - Application number: 08/411,963 - Filed: 1995-03-28 - Granted: 1997-12-23 - Earliest claimed: 1994-03-30 - Assignees: Canon Kabushiki Kaisha - Inventors: Yutaka Kurbayashi; Katsuhiro Shirota; Katsuhiko Takahashi - Web page: https://patentgrep.com/patent/US5700314A ## CPC - C09D 11/40: Ink-sets specially adapted for multi-colour inkjet printing - B41J 2/01: Ink jet - 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 ## Abstract An ink set comprising a combination of a liquid composition containing a cationic substance, with a yellow ink, a cyan ink and magenta ink, wherein said three inks each contain a water soluble anionic dye and are capable of affording a chromaticity CIE L*a*b* to a black image presented on a recording medium by using these inks in combination within the range of the numerical expressions: 10.ltoreq.L*.ltoreq.30, 0.ltoreq.a*.ltoreq.7, and -10.ltoreq.b*.ltoreq.0. ## Claims ### Claim 1 An ink set comprising a combination of a liquid composition comprising a low-molecular weight cationic substance and a high-molecular weight cationic substance in combination, with a yellow ink, a cyan ink and a magenta ink, wherein said three inks each contain a water-soluble anionic dye and are capable of affording a chromaticity CIE L*a*b* to a black image presented on a recording medium by using these inks in combination within the range of the numerical expressions: 10.ltoreq.L*.ltoreq.30, 0.ltoreq.a*.ltoreq.7, and -10.ltoreq.b*.ltoreq.0. ### Claim 2 (depends on 1) The ink set according to claim 1, wherein said anionic dye is any one of an acid dye, a direct dye and a reactive dye. ### Claim 3 (depends on 1) The ink set according to claim 1, wherein said anionic dye is contained in each of said inks in an amount of from 0.1% by weight to 15% by weight based on the total weight of the ink. ### Claim 4 (depends on 1) The ink set according to claim 1, wherein said liquid composition comprises a cationic substance with a molecular weight of 1,000 or less and a cationic substance with a molecular weight of 1,500 or more in combination. ### Claim 5 (depends on 1) The ink set according to claim 1, wherein said low-molecular weight cationic substance has a molecular weight ranging from 100 to 700. ### Claim 6 (depends on 1) The ink set according to claim 1, wherein said high-molecular weight cationic substance has a molecular weight ranging from 1,500 to 10,000. ### Claim 7 (depends on 1) The ink set according to claim 1, wherein said each ink further contains water and a water-soluble organic solvent. ### Claim 8 (depends on 1) The ink set according to claim 1, wherein said liquid composition further contains water and a water-soluble organic solvent. ### Claim 9 (depends on 1) The ink set according to claim 1, wherein said each ink contains water in an amount ranging from 10% by weight to 97.5% by weight based on the total weight of the ink. ### Claim 10 (depends on 1) The ink set according to claim 1, wherein said each ink contains a water-soluble organic solvent in an amount ranging from 2% by weight to 80% by weight based on the total weight of the ink. ### Claim 11 (depends on 1) The ink set according to claim 1, wherein said each ink has a viscosity at 25.degree. C. in the range of from 1 cP to 20 cP. ### Claim 12 (depends on 1) The ink set according to claim 1, wherein said each ink has a surface tension of 30 dyne/cm or above. ### Claim 13 (depends on 1) The ink set according to claim 1, wherein said each ink has a pH value ranging from 6 to 10. ### Claim 14 (depends on 1) The ink set according to claim 1, wherein said yellow ink or cyan ink comprises further an anionic surface active agent or an anionic high-molecular weight substance other than the dye. ### Claim 15 (depends on 1) The ink set according to claim 1, wherein said magenta ink contains a dye represented by the formula: ##STR3## wherein R.sub.1 and R.sub.2 each represent H, CH.sub.3, OCH.sub.3, --SO.sub.3 M or --COOM, and R.sub.3 is --COCH.sub.3, ##STR4## wherein R.sub.4 and R.sub.5 each represent --COOM, R.sub.6 or --OR.sub.6, where R.sub.6 represents a C.sub.2 to C.sub.6 alkyl chain which may be branched; and M represents sodium, lithium, an organic amine or ammonium. ### Claim 16 An image forming method comprising forming a black portion by using a liquid composition comprising a low-molecular weight cationic substance and a high-molecular weight cationic substance, in combination with a yellow ink, a cyan ink and a magenta ink, wherein said three inks each contain a water-soluble anionic dye and are capable of affording a chromaticity CIE L*a*b* to a black image presented on a recording medium by using these inks in combination within the range of the numerical expressions: 10.ltoreq.L*.ltoreq.30, 0.ltoreq.a*.ltoreq.7, and -10.ltoreq.b*.ltoreq.0. 17. ### Claim 17 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15) An image forming method comprising imparting a liquid composition, a yellow ink, a cyan ink and a magenta ink by an ink-jet system to record a black portion, wherein the ink set according to any one of claims 1-15 is applied. ### Claim 18 (depends on 17) The image method according to claim 17, wherein said ink-jet system is a system comprising applying a heat energy to the ink to generate ink droplets. ### Claim 19 (depends on 17) The image forming method according to claim 17, wherein said yellow ink and cyan ink are each imparted to the recording medium in a quantity larger by 10% to 50% with respect to that of said magenta ink. ### Claim 20 (depends on 17) The image forming method according to claim 17, wherein the ink shot duty of said magenta ink is controlled within the range of from 50% to 80% of that of said yellow ink and cyan ink each. ### Claim 21 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15) A recording unit comprising holders for a liquid composition and an ink and a head that ejects the liquid composition and the ink in the form of droplets, wherein the ink set according to any one of claims 1-15 is applied. ### Claim 22 (depends on 21) The recording unit according to claim 21, wherein an ink-jet system that generates ink droplets by the action of heat energy is applied to said head. ### Claim 23 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15) An ink cartridge comprising holders for a liquid composition and an ink, wherein the ink set according to any one of claims 1-15 is applied. ### Claim 24 (depends on 21) An ink-jet recording apparatus comprising the recording unit according to claim 21. ### Claim 25 (depends on 22) An ink-jet recording apparatus comprising the recording unit according to claim 22. ### Claim 26 (depends on 23) An ink-jet recording apparatus comprising the ink cartridge according to claim 23. ### Claim 27 (depends on 23) The ink-jet recording apparatus according to claim 23, having a head for generating ink droplets by an ink-jet system. ### Claim 28 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15) An ink-jet recording apparatus comprising the ink set according to any one of claims 1-15. ### Claim 29 (depends on 28) The ink-jet recording apparatus according to claim 28, further having a head for generating ink droplets by an ink-jet system. ### Claim 30 An image which is presented using a liquid composition comprising a low-molecular weight cationic substance and a high-molecular weight cationic substance, in combination with a yellow ink, a cyan ink and a magenta ink, and contains a black portion having on a recording medium a chromaticity CIE L*a*b* within the range of the following numerical expressions: 10.ltoreq.L*.ltoreq.30, 0.ltoreq.a*.ltoreq.7, and -10.ltoreq.b*.ltoreq.0.