Particle Size of Commercial Inks and Their Deinkability

The particle size analysis of commercially available process color inks for major printing processes was performed using Submicron 370 NICOMP Particle Sizer. Uncoated toluene based publication gravure ink had slightly smaller particle size than coated toluene based publication gravure ones. Flexo water based inks exhibited smaller particles than publication gravure ones. No relationship was found between colors and their particle sizes within inks for gravure and flexo printing processes. Deinkability was measured up to four weeks after printing as a color difference ?E of handsheets before and after deinking. Flotation deinkability of gravure inks slightly decreased with increasing particle size of liquid inks and rapidly decreased with the particle size of flexo inks. Washing deinkability for both processes also decreased with decreasing particle size of liquid inks.