Ink composition, ink set, and black ink set

Abstract

Disclosed herein is an ink composition, including: a pigment; acetylenediol having an HLB of less than 4; and an anionic surfactant, in which the mass ratio of the acetylene diol to the anionic surfactant is 0.30 to 4.0.

What is claimed is: 
     
         1 . An aqueous ink composition configured for use in an ink jet recording apparatus having a nozzle for ejecting the ink composition and a suction cap that defines a cap space that includes an ink absorber therein, the suction cap being configured to seal the nozzle for evacuating the cap space, the ink composition comprising:
 a pigment, a content of the pigment being equal to or greater than 5.0 mass %;   acetylenediol having an HLB of less than 4, a content of the acetylenediol being 0.010 mass % to 0.40 mass %;   a 1,2-alkanediol having 4 to 6 carbon atoms, a content of the 1,2-alkanediol having 4 to 6 carbon atoms being 0.50 mass % to 6.0 mass %; and   an anionic surfactant, a content of the anionic surfactant being 0.025 mass % to 0.25 mass %,   wherein the solubility of the acetylenediol having an HLB of less than 4 in water being improved by the anionic surfactant,   a mass ratio of the acetylenediol to the anionic surfactant is 0.30 to 4.0, and   a mass ratio of the acetylenediol to the 1,2-alkanediol is 0.0010 to 0.100.   
     
     
         2 . The ink composition according to  claim 1 , wherein the acetylenediol includes 2,5,8,11-tetramethyl-6-dodecyne-5,8-diol. 
     
     
         3 . The ink composition according to  claim 1 , wherein the anionic surfactant contains at least one selected from the group consisting of polyoxyethylene-based compounds and sulfates. 
     
     
         4 . The ink composition according to  claim 1 , wherein the content of the pigment is 5.0 mass % to 10 mass %. 
     
     
         5 . The ink composition according to  claim 1 , further comprising an acetylenediol derivative having an HLB of equal to or greater than 7. 
     
     
         6 . The ink composition according to  claim 1 , further comprising a pyrrolidone derivative, a content of the pyrrolidone derivative being 1.0 mass % to 12 mass %. 
     
     
         7 . The ink composition according to  claim 1 , wherein a dissolved nitrogen content is equal to or greater than 10 ppm. 
     
     
         8 . The ink composition according to  claim 1 , wherein the pigment contains self-dispersing carbon black. 
     
     
         9 . An ink set, comprising:
 a self-dispersing black ink, which is the ink composition according to  claim 8 ; and   a color ink.   
     
     
         10 . A black ink set, comprising:
 a self-dispersing black ink, which is the ink composition according to  claim 8 ; and   a resin-dispersing black ink containing resin-dispersing carbon black and acetylenediol having an HLB of less than 4,   wherein the content of the acetylenediol contained in the resin-dispersing black ink is lower than the content of the acetylenediol contained in the self-dispersing black ink, and   the content of the resin-dispersing carbon black is equal to or less than 3.0 mass %.   
     
     
         11 . An ink jet recording apparatus, comprising:
 the ink composition according to  claim 1 ;   a nozzle for ejecting the ink composition; and   a suction cap that seals the nozzle,   the suction cap defining a cap space that includes an ink absorber therein, and the cap space configured to be evacuated when the suction cap seals the nozzle.   
     
     
         12 . An ink jet recording apparatus, comprising:
 the ink composition according to  claim 2 ;   a nozzle for ejecting the ink composition; and   a suction cap that seals the nozzle,   the suction cap defining a cap space that includes an ink absorber therein, and the cap space configured to be evacuated when the suction cap seals the nozzle.   
     
     
         13 . An ink jet recording apparatus, comprising:
 the ink composition according to  claim 3 ;   a nozzle for ejecting the ink composition; and   a suction cap that seals the nozzle,   the suction cap defining a cap space that includes an ink absorber therein, and the cap space configured to be evacuated when the suction cap seals the nozzle.   
     
     
         14 . The ink composition according to  claim 5 , wherein the acetylenediol derivative having an HLB of equal to or greater than 7 is selected from the group consisting of an alkylene oxide adduct of 2,5,8,11-tetramethyl-6-decyne-5,8-diol, 2,4-dimethyl-5-decyne-4-ol, and an alkylene oxide adduct of 2,4-dimethyl-5-decyne-4-ol.