Water-based ink for ink jetting and ink jet recording method

Abstract

A water-based ink for ink jetting and ink jet recording method, in which stable jetting, clearness of the recorded matter, high density recording, water resistance, and friction resistance are well-balanced, and being useful for ink for various types of ink jet recording. After 5% of the water soluble colored resin comprising 5,5′-dimethylhydantoinformaldehyde resin and color index number basic red 1:1 and 10% of polyethyleneglycol (average molecular weight 200) and 6% of triethyleneglycolmonometylether and 79% of pure water are fully stirred to be mixed, the mixture is filtered with a membrane filter of 0.8 μm thickness to become ink. Experimental evaluation using the recording head regarding jetting stability, jetting response, quality of the recorded images, friction resistance against various recording materials, and water resistance against various recording materials is made, and good results are obtained.

What is claimed is:  
     
         1 . Water-based ink for ink jetting comprising water, a water soluble organic solvent and a coloring agent as essential components, 
 wherein the coloring agent comprises a water soluble colored resin wherein a water soluble resin as a main component of the coloring agent is uniformly coloring processed by a basic dye.    
     
     
         2 . The water-based ink for ink jetting according to  claim 1 , wherein the water soluble resin component of the water soluble colored resin is selected from the group consisting of 5,5′-dimethylhydantoinformaldehyde resin obtained by copolymerization of 5,5′-dimethylhydantoin and formaldehyde, 1-methylol-5,5′-dimethylhydantoin resin obtained by condensation polymerization of 1-methylol-5,5′-dimethylhydantoin, and polyvinylpyrrolidone obtained by addition polymerization of vinylpyrolidone.  
     
     
         3 . The water-based ink for ink jetting according to  claim 1 , wherein a weight molecular weight of the water soluble resin of the water soluble colored resin is equal to or less than 10000.  
     
     
         4 . The water-based ink for ink jetting according to  claim 1 , wherein a compounding ratio of the water soluble resin and the basic dye in the water soluble colored resin is within a range of 10:1 to 1:1.  
     
     
         5 . The water-based ink for ink jetting according to  claim 1 , wherein a content amount of the water soluble colored resin in the ink is from 1 to 10 weight %.  
     
     
         6 . The water-based ink for ink jetting according to  claim 2 , wherein the 5,5′-dimethylhydantoinformaldehyde resin is obtained by copolymerization of 5,5′-dimethylhydantoin and formaldehyde, the 1-methylol-5,5′-dimethylhydantoin resin is obtained by condensation polymerization of 1-methylol-5,5′-dimethylhydantoin, and the polyvinylpyrrolidone is obtained by addition polymerization of vinylpyrolidone.  
     
     
         7 . The water-based ink for ink jetting according to  claim 1 , wherein the coloring agent is in a form of microsuspension bodies that include both resin and dye molecules.  
     
     
         8 . Ink jet recording method for a recording operation by flying minute droplets of water-based ink for ink jetting that comprises water, a water soluble organic resin and a coloring agent as essential components, wherein the water-based ink for ink jetting of  claim 1  is used as the ink.  
     
     
         9 . Water-based ink for ink jetting comprising water, a water soluble organic solvent and a coloring agent as essential components, 
 wherein the coloring agent comprises a water soluble colored resin formed by uniformly coloring processing a water soluble resin by a basic dye.    
     
     
         10 . The water-based ink for ink jetting according to  claim 9 , wherein the water soluble resin component of the water soluble colored resin is selected from the group consisting of 5,5′-dimethylhydantoinformaldehyde resin obtained by copolymerization of 5,5′-dimethylhydantoin and formaldehyde, 1-methylol-5,5′-dimethylhydantoin resin obtained by condensation polymerization of 1-methylol-5,5′-dimethylhydantoin, and polyvinylpyrrolidone obtained by addition polymerization of vinylpyrolidone.  
     
     
         11 . The water-based ink for ink jetting according to  claim 9 , wherein a weight molecular weight of the water soluble resin of the water soluble colored resin is equal to or less than 10000.  
     
     
         12 . The water-based ink for ink jetting according to  claim 9 , wherein a compounding ratio of the water soluble resin and the basic dye in the water soluble colored resin is within a range of 10:1 to 1:1.  
     
     
         13 . The water-based ink for ink jetting according to  claim 9 , wherein a content amount of the water soluble colored resin in the ink is from 1 to 10 weight %.  
     
     
         14 . The water-based ink for ink jetting according to  claim 10 , wherein the 5,5′-dimethylhydantoinformaldehyde resin is obtained by copolymerization of 5,5′-dimethylhydantoin and formaldehyde, the 1-methylol-5,5′-dimethylhydantoin resin is obtained by condensation polymerization of 1-methylol-5,5′-dimethylhydantoin, and the polyvinylpyrrolidone is obtained by addition polymerization of vinylpyrolidone.  
     
     
         15 . The water-based ink for ink jetting according to  claim 9 , wherein the coloring agent is in a form of microsuspension bodies that include both resin and dye molecules.  
     
     
         16 . The water-based ink for ink jetting according to  claim 9 , wherein the uniformly coloring processing is conducted at a temperature about 60° C. or higher.  
     
     
         17 . Ink jet recording method for a recording operation by flying minute droplets of water-based ink for ink jetting that comprises water, a water soluble organic resin and a coloring agent as essential components, wherein the water-based ink for ink jetting of  claim 9  is used as the ink.  
     
     
         18 . A process for forming a water-based ink for ink jetting comprising 
 uniformly coloring processing a water soluble resin by a basic dye to form microsuspension bodies;    dispersing said microsuspension bodies in a liquid medium comprising water and a water soluble organic solvent.    
     
     
         19 . The process according to  claim 18 , wherein the uniformly coloring processing is conducted at a temperature about 60° C. or higher.