Water-Based Ink for Ink-Jet Recording, Ink Cartridge and Method for Producing Water-Based Ink for Ink-Jet Recording

Abstract

A water-based ink for ink-jet recording includes: a water-soluble colorant; water; a water-insoluble liquid; a nonionic surfactant; and an ionic surfactant having a polarity same as that of the water-soluble colorant. The water-insoluble liquid is dispersed stably in the water by the nonionic surfactant and the ionic surfactant having the polarity same as that of the water-soluble colorant.

What is claimed is: 
     
         1 . A water-based ink for ink-jet recording comprising:
 a water-soluble colorant;   water;   a water-insoluble liquid;   a nonionic surfactant; and   an ionic surfactant having a polarity same as that of the water-soluble colorant;   wherein the water-insoluble liquid is dispersed in the water by the nonionic surfactant and the ionic surfactant having the polarity same as that of the water-soluble colorant.   
     
     
         2 . The water-based ink for ink-jet recording according to  claim 1 , wherein boiling point of the water-insoluble liquid is not less than 250 degrees Celsius. 
     
     
         3 . The water-based ink for ink-jet recording according to  claim 2 , wherein the water-insoluble liquid is one kind selected from the group consisting of: diethyl adipate, diethyl phthalate and polypropylene glycol. 
     
     
         4 . The water-based ink for ink-jet recording according to  claim 2 , wherein the water-insoluble liquid is diethyl adipate. 
     
     
         5 . The water-based ink for ink-jet recording according to  claim 1 , wherein the water-insoluble liquid is a saturated hydrocarbon of which carbon atom number is not less than 10. 
     
     
         6 . The water-based ink for ink-jet recording according to  claim 1 , wherein the water-insoluble liquid is dodecane. 
     
     
         7 . The water-based ink for ink-jet recording according to  claim 1 , wherein weight ratio of the water-insoluble liquid (X) and the nonionic surfactant (Y) is in a range of X:Y=10:1 to 1:4, and weight ratio of the water-insoluble liquid (X) and the ionic surfactant having the polarity same as that of the water-soluble colorant (Z) is in a range of X:Z=25:1 to 1:3. 
     
     
         8 . The water-based ink for ink-jet recording according to  claim 1 , wherein a blending amount of the water-soluble colorant in an entire amount of the water-based ink is in a range of 1% by weight to 3% by weight. 
     
     
         9 . The water-based ink for ink-jet recording according to  claim 1 , wherein the nonionic surfactant includes at least one of a sorbit-based surfactant and an acetylenic glycol-based surfactant. 
     
     
         10 . The water-based ink for ink-jet recording according to  claim 1 , wherein the ionic surfactant having the polarity same as that of the water-soluble colorant includes at least one of an anionic surfactant having a sulfate-structure and a quaternary ammonium salt represented by the following formula (4): 
       
         
           
           
               
               
           
         
         wherein in the formula (4), each of R 1 , R 2 , R 3  and R 4  is an alkyl group of which carbon atom number is 1 to 18, and R 1 , R 2 , R 3  and R 4  are identical to one another or are different from one another. 
       
     
     
         11 . An ink cartridge configured to contain a water-based ink for ink-jet recording, wherein the water-based ink is the water-based ink for ink-jet recording as defined in  claim 1 . 
     
     
         12 . A method for producing the water-based ink for ink-jet recording as defined in  claim 1 , the method comprising:
 a step of preparing a first liquid by mixing a water-soluble colorant and water; and   a step of preparing a second liquid by mixing a water-insoluble liquid and a nonionic surfactant;   a step of preparing a third liquid by mixing the water and an ionic surfactant having a polarity same as that of the water-soluble colorant;   a step of preparing a fourth liquid by mixing the second liquid and the third liquid; and   a step of preparing the water-based ink for ink-jet recording by mixing the fourth liquid and the first liquid.   
     
     
         13 . The method for producing the water-based ink for ink-jet recording according to  claim 12 , wherein boiling point of the water-insoluble liquid is not less than 250 degrees Celsius. 
     
     
         14 . The method for producing the water-based ink for ink-jet recording according to  claim 13 , wherein the water-insoluble liquid is one kind selected from the group consisting of: diethyl adipate, diethyl phthalate and polypropylene glycol. 
     
     
         15 . The method for producing the water-based ink for ink-jet recording according to  claim 13 , wherein the water-insoluble liquid is diethyl adipate. 
     
     
         16 . The method for producing the water-based ink for ink-jet recording according to  claim 12 , wherein the water-insoluble liquid is a saturated hydrocarbon of which carbon atom number is not less than 10. 
     
     
         17 . The method for producing the water-based ink for ink-jet recording according to  claim 16 , wherein the water-insoluble liquid is dodecane. 
     
     
         18 . The method for producing the water-based ink for ink-jet recording according to  claim 12 , wherein in the step of preparing the second liquid, weight ratio of the water-insoluble liquid (X) and the nonionic surfactant (Y) is adjusted to be in a range of X:Y=10:1 to 1:4; and
 in the step of preparing the fourth liquid, weight ratio of the water-insoluble liquid (X) and the ionic surfactant having the polarity same as that of the water-soluble colorant (Z) is adjusted to be in a range of X:Z=25:1 to 1:3.