Solvent-based ink composition with ketone solvent and surface-modified pigment

Abstract

A solvent-based ink composition for a thermal inkjet printhead. The composition includes: (a) 10-80 wt. % of a compound of formula (B): wherein: R 5 is a C 1-6 alkyl group and R 6 is a C 1-6 alkyl group; or R 5 and R 6 are together joined to form a C 3-12 cycloalkylene group; (b) 10-80 wt. % of a C 1-6 alcohol; and (c) 0.01-25 wt. % of a surface-modified pigment.

1 . A solvent-based ink composition for a thermal inkjet printhead comprising:
 (a) 10-80 wt. % of a compound of formula (B);   
       
         
           
           
               
               
           
         
         wherein: 
         R 5  is a C 1-6  alkyl group and R 6  is a C 1-6  alkyl group; or 
         R 5  and R 6  are together joined to form a C 3-12  cycloalkylene group; 
         (b) 10-80 wt. % of a C 1-6  alcohol; and 
         (c) 0.01-25 wt. % of a surface-modified pigment. 
       
     
     
         2 . The ink composition of  claim 1 , wherein the compound of formula (B) is methylethylketone. 
     
     
         3 . The ink composition of  claim 1 , wherein the compound of formula (B) is cyclohexanone. 
     
     
         4 . The ink composition of  claim 1 , wherein said C 1-6  alcohol is ethanol. 
     
     
         5 . The ink composition of  claim 1 , wherein said pigment has a surface modified with an anionic or a cationic group. 
     
     
         6 . The ink composition of  claim 1 , wherein said surface is modified with a carboxylate group or a sulfonate group. 
     
     
         7 . The ink composition of  claim 1 , comprising 0.001-10 wt. % of a surfactant or dispersant. 
     
     
         8 . The ink composition of  claim 7 , wherein said surfactant or dispersant is nonionic. 
     
     
         9 . The ink composition of  claim 1 , wherein said composition does not comprise an acrylate polymer or copolymer. 
     
     
         10 . The ink composition of  claim 1 , wherein said composition does not comprise any polymers. 
     
     
         11 . The ink composition of  claim 1 , consisting essentially of said compound of formula (B), said C 1-6  alcohol and said colorant. 
     
     
         12 . An ink cartridge for a thermal inkjet printhead, said ink cartridge containing the solvent-based ink composition according to  claim 1 . 
     
     
         13 . A printhead cartridge comprising a thermal inkjet printhead integrated therewith and an ink reservoir containing the ink composition according to  claim 1 . 
     
     
         14 . A substrate having an ink composition according to  claim 1  disposed thereon. 
     
     
         15 . The substrate of  claim 14 , which is a semi-porous or non-porous substrate. 
     
     
         16 . The substrate of  claim 15 , which is a vinyl substrate. 
     
     
         17 . A method of ejecting ink from a thermal inkjet printhead, said method comprising the steps of:
 (i) supplying an ink to at least one nozzle chamber of the printhead; and   (ii) actuating a heater element in the nozzle chamber so as to heat a portion of the ink to a temperature sufficient to form a bubble therein, thereby causing a droplet of ink to be ejected from a nozzle opening associated with the nozzle chamber,   
       wherein the ink is the solvent-based ink composition according to  claim 1 .