By Steve Liker, Product Manager – Large Character Ink Jet Ink Jet printing enables variable information to be printed on multiple substrates including uncoated and coated corrugated cartons, gypsum, PVC piping, lumber and other materials. When choosing the ink to jet from your ink jet five criteria should be considered: 1) Substrate Type The ink ultimately needs to contact the substrate, spread, dry and adhere with acceptable adhesion and durability. The substrate needs to be categorized as “porous” – absorbing the ink, or “non-porous” – ink spreading, but ink sits on the surface of the substrate. Inks printed onto porous substrates dry through absorption into the substrate fibers. Inks printed onto non-porous substrates dry through evaporation. Why not chose non-porous for all applications? Because the evaporative inks tend to require more maintenance than the less evaporative porous inks. Diagraph offers ink jet inks for both porous and non-porous substrates. 2) Dry Time and Adhesion The choice of inks could be determined by the time period between printing and contacting conveyor rails and rollers or with contacting other cartons or products. Do some investigation taking into consideration conveyor speed and location of objects that may contact the print. For example, a carton is traveling at 100 feet per minute (20 inches per second). A roller is located 60 inches away and contacts the ink jet printed image. Therefore the dry time with acceptable adhesion must be less than 3 seconds to avoid chance of smudging. Diagraph has data on dry times and adhesion or could perform print samples on your substrate and measure the dry time and adhesion to help you chose the right ink. 3) Lightfastness Will the substrate ultimately be exposed to direct outdoor light or to indoor light? If it will be exposed to outdoor light for days or weeks at a time then “pigmented” inks are recommended. Pigments are particles of colorant in solution. Dyes are liquids in liquids. Particles tend to maintain lightfastness much better than dye colorants. Diagraph offers both dye based and pigment based inks with information available on the ink lightfastness. 4) Image Are you planning on printing text or barcodes? Since barcodes will be scanned and measured with a barcode scanner they require finer control over the dot spread than text. Dyes tend to spread more than pigment particles by wicking along the corrugated carton fibers. Therefore, pigmented inks may be your best choice for barcode printing. 5) Color You may wish to consider printing with spot colors to readily identify and differentiate your products. That way for example your employees and your customers can learn to identify the carton containing your lime flavored soda from afar by seeing the Green text. Diagraph offers multiple ink colors. So when deciding on the ink jet inks consider the above criteria. Diagraph’s Customer Service Associates and Applications Engineers are also available to guide you through this ink decision process.