In ink containing a colorant, a humectant, a penetrant, water, and a water-soluble substance that is condensation-polymerized in the absence of the water (e.g., hydrolyzable silane compound), the surface tension of the ink at 25° C. before the water-soluble substance is condensation-polymerized is set...http://www.google.com/patents/US7196121?utm_source=gb-gplus-sharePatent US7196121 - Inkjet recording ink, solvent for use in said ink and cartridge and recording device having said ink
