# US 7,410,234 B2 · Ink-jet printer and ink jetting method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,410,234 B2 - Document ID: US7410234B2 - Status: Granted - Kind: B2 - Application number: 11/638,921 - Filed: 2006-12-14 - Published: 2007-06-14 - Granted: 2008-08-12 - Earliest claimed: 2005-12-14 - Assignees: Brother Kogyo Kabushiki Kaisha - Inventors: Koichiro Hara - Web page: https://patentgrep.com/patent/US7410234B2 ## CPC - B41J 2/15: for serial printing - B41J 2/2128: {by means of energy modulation (control methods or devices therefor, e.g. driver circuits or control circuits B41J2/04501)} - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract In an ink-jet head including black, yellow, magenta, cyan nozzle rows, the nozzle rows are arranged so that in each of the nozzle rows, adjacent nozzles are arranged by a predetermined spacing distance P, and that the black nozzle row is shifted in a nozzle-row alignment direction by a spacing distance smaller than the predetermined spacing distance P, with respect to the cyan, magenta and yellow nozzle rows. When a black dot is formed between monochrome-black dots adjacent in the sub-scanning direction, a dot of color-mixed black which is a mixture of the other three colors is formed between the monochrome-black dots. At this time, by adjusting a black-ink jetting amount to be greater than a total amount of the other three color inks, it is possible to make the monochrome-black dot and the color-mixed black dot to be mutually uniform in size. ## Claims ### Claim 1 An ink-jet printer which performs recording on a recording medium by jetting a black ink, a yellow ink, a magenta ink, and a cyan ink, the ink-jet printer comprising: an ink-jet head including black, cyan, magenta and yellow nozzle rows each of which is formed of a plurality of nozzles arranged in a predetermined direction, and which are aligned in a direction orthogonal to the predetermined direction; and a controller which controls the ink-jet head; wherein adjacent nozzles, among the nozzles in each of the nozzle rows, are arranged at a predetermined spacing distance P; the black nozzle row is shifted, in the predetermined direction by a spacing distance ΔP smaller than the predetermined spacing distance P, from the cyan, magenta and yellow nozzle rows, respectively; when a black dot is formed between monochrome-black dots of monochrome black which are adjacent to each other in the predetermined direction and which are formed by jetting the black ink, the controller controls the ink-jet head so that the yellow ink, the magenta ink, and the cyan ink are jetted from nozzles to form a color-mixed black dot of color-mixed black which is a mixture of the yellow ink, the magenta ink, and the cyan ink; and the controller controls the ink-jet head so that an amount of the black ink which is jetted to form one dot of the monochrome-black dots is greater than a total amount of the yellow ink, the magenta ink, and the cyan ink jetted to form the color-mixed black dot. ### Claim 2 (depends on 1) The ink-jet printer according to claim 1, wherein the black nozzle row is shifted, in the predetermined direction by ½ of the predetermined spacing distance P, from the cyan, magenta and yellow nozzle rows, respectively. ### Claim 3 (depends on 1) The ink-jet printer according to claim 1, wherein the nozzles which form the black nozzle row and which jet the black ink have an opening which is greater in size than that of the nozzles which form the cyan, magenta and yellow nozzle rows and which jet the cyan, magenta and yellow inks, respectively. ### Claim 4 (depends on 3) The ink-jet printer according to claim 3, wherein, when the color-mixed black dot is formed between the monochrome-black dots, an amount of the yellow ink, an amount of the magenta ink, and an amount of the cyan ink jetted to form the color-mixed black dot are each adjusted to be smaller than the amount of the black ink jetted to form one dot of the monochrome-black dots. ### Claim 5 (depends on 3) The ink-jet printer according to claim 3, wherein an ink each of the yellow ink, the magenta ink, and the cyan ink blurs more easily with respect to the recording medium than the black ink. ### Claim 6 (depends on 5) The ink-jet printer according to claim 5, wherein the black ink is a pigment ink; and wherein the yellow ink, the magenta ink, and the cyan ink are dye inks. ### Claim 7 (depends on 1) The ink-jet printer according to claim 1, wherein the amount of the black ink jetted to form one dot of the monochrome-black dots is 1.3 to 1.5 times an amount of each of the yellow, magenta, and cyan inks jetted to form one dot of each of the yellow, magenta, and cyan inks in a size same as that of one dot of the monochrome-black dots. ### Claim 8 (depends on 1) The ink-jet printer according to claim 1, wherein when the color-mixed black dot is formed between the monochrome-black dots, the amount of the black ink jetted to form one dot of the monochrome-black dots is smaller than a maximum ink amount jettable for forming one dot of the monochrome-black dots from each of the nozzles which form the black nozzle row and which jet the black ink. ### Claim 9 An ink jetting method for jetting a black ink, a yellow ink, a magenta ink, and a cyan ink from, the method comprising: preparing an ink-jet head which includes black, cyan, magenta and yellow nozzle rows each formed of a plurality of nozzles arranged in a predetermined direction at a predetermined spacing distance P, and are aligned in a direction orthogonal to the predetermined direction, and in which the black nozzle row is shifted, in the predetermined direction by a spacing distance ΔP smaller than the predetermined spacing distance P, from the cyan, magenta and yellow nozzle rows, respectively; jetting the yellow ink, the magenta ink, the cyan ink concurrently so as to form a color-mixed black dot of color-mixed black which is a mixture of the yellow ink, the magenta ink, and the cyan ink, when a black dot is formed between monochrome-black dots of monochrome black which are adjacent to each other in the predetermined direction and which are formed by jetting the black ink; and adjusting an amount of the black ink to be greater than a total amount of the yellow ink, the magenta ink, and the cyan ink jetted for forming the color-mixed black dot, when one dot of the monochrome-black dots is formed. ### Claim 10 (depends on 9) The ink jetting method according to claim 9, wherein the black nozzle row is shifted, in the predetermined direction by ½ of the predetermined spacing distance P, from the cyan, magenta and yellow nozzle rows respectively. ### Claim 11 (depends on 9) The ink jetting method according to claim 9, wherein the nozzles which form the black nozzle row and which jet the black ink have an opening which is greater in size than the nozzles which form the cyan, magenta and yellow nozzle rows and which jet the cyan, magenta and yellow inks, respectively. ### Claim 12 (depends on 9) The ink jetting method according to claim 9, wherein an ink each of the yellow ink, the magenta ink, and the cyan ink blurs more easily with respect to the recording medium than the black ink. ### Claim 13 (depends on 12) The ink-jet printer according to claim 12, wherein the black ink is a pigment ink; and wherein the yellow ink, the magenta ink, and the cyan ink are dye inks.