Abstract: The present invention provides a jet ink composition comprising a volatile organic solvent, an oil, one or more binder resins which are soluble in the volatile organic solvent, and a colorant. The ink composition is fast drying and provides excellent adhesion to non-porous substrates. Printers, such as drop-on-demand ink jet printers, employing the ink composition can operate without nozzle clogging even after long non-printing intervals. The present invention further provides a method for reducing clogging of a nozzle orifice in an ink jet printer comprising printing with an ink composition that includes an oil that forms a continuous oil phase which acts as the boundary layer between the air outside the nozzle orifice and the ink inside the nozzle during non-printing intervals.

Abstract: The present invention provides a jet ink composition suitable for application onto a substrate comprising an ink carrier, a colorant, a polyol, an aldehyde-based cross-linking agent, and a catalyst that promotes a reaction between the cross-linking agent, the polyol, and the substrate. The present invention further provides a process of jet ink printing onto a substrate comprising projecting a stream of ink droplets to said substrate, controlling the direction of the droplets so that the droplets form the desired printed image on the substrate, and heating the image to obtain a cured printed image. Examples of preferred cross-linking agents are modified melamine formaldehyde resin and modified urea formaldehyde resin. The substrates preferably possess carboxyl, hydroxyl, amide, or sulfhydryl groups. An example of a preferred substrate is cellulose. The cross-linking reaction is carried out at relatively moderate temperatures and at high speeds.