Cosolvents in printing fluids

摘要

Disclosed is an aqueous fixer fluid useful for printing before or after an aqueous inkjet ink, the aqueous fixer comprising at least one anti-curl cosolvent, wherein the at least one anti-curl cosolvent comprises at least one inner salt compound having a sp3-hybridized nitrogen cation and an associated anionic charge which is: isolated on an oxygen anion bound directly to the sp3-hybridized nitrogen cation; or isolated among the oxygens of a carboxylate group, wherein the at least one inner salt compound is an ammonium-N-oxide moiety, which when mixed with a strong acid gives an ammonium-N-oxide conjugate acid with an approximate pKa = 4-5 and a buffering capacity in aqueous solution near pH = 4-5.