Abstract: Hydroxyethylated polyethyleneimine is added to jet ink having an anionic dye to prevent whisker forming overnight. To avoid excessive viscosity at start-up, the polyethyleneimine is low molecular weight or a low molecular weight hydroxyethylated amine is combined with high molecular weight polyethyleneimine.

Abstract: A waterfast ink having 3.0% Food Black 2, 2.5% highly hydroxyethylated polyethyleneimine, 10.0% ammonium benzoate, and the balance water. The invention appears to function upon loss of water after printing by a polar neutralizing between the dye and the polyimine, which results in an affinity of the dye to paper. It is applicable to any dye having anionic solubilizing groups but not having quaternary ammonium and to any ammonium salt.

Abstract: A printer, such as an ink jet printer, incorporates various hardware such as the ink supply tank, tubing, and ink drop gutter, as representative items, having components molded in the hardware which disinfect groups of micro-organisms which present problems, particularly in areas where ink has depleted. The techniques described lead to inactivation of vegetative bacteria and fungi and prevention of maturation of spores in those areas not in frequent control with the biocide component of the ink. Also mutant forms are prevented from developing in those areas where the biocide component concentration is below the effective lethal level.