Sulfonated dye salts exhibiting reduced kogation

Abstract

A sulfonated dye salt of formula (II): wherein M is Ga(A 1 ); A 1 is an axial ligand selected from the group consisting of: —OH and halogen; and Z 1 + , Z 2 + , Z 3 + and Z 4 + are independently selected from the group consisting of: H and an ammonium cation. At least one of Z 1 + , Z 2 + , Z 3 + and Z 4 + is the ammonium cation. The ammonium cation is protonated 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol. Such salts exhibit reduced kogation in thermal bubble-forming inkjet printheads.

1 . A sulfonated dye salt of formula (II): 
       
         
           
           
               
               
           
         
         wherein 
         M is Ga(A 1 ); 
         A 1  is an axial ligand selected from the group consisting of: —OH and halogen; and 
         Z 1   + , Z 2   + , Z 3   +  and Z 4   +  are independently selected from the group consisting of: H and an ammonium cation, wherein at least one of Z 1   + , Z 2   + , Z 3   +  and Z 4   +  is said ammonium cation and said ammonium cation is protonated 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol. 
       
     
     
         2 . The sulfonated dye salt of  claim 1 , wherein at least three of Z 1   + , Z 2   + , Z 3   +  and Z 4   +  are said ammonium cation. 
     
     
         3 . The sulfonated dye salt of  claim 1 , wherein each of Z 1   + , Z 2   + , Z 3   +  and Z 4   +  is said ammonium cation.