Question #1: What are the various printing processes for printing harsh environment labels?
Here is a discussion of the various printing technologies commonly used today.
Thermal Transfer. Heat is used to transfer a resin or wax-based ink from a ribbon coated on one side, to the blank label stock. Resin ribbons are quite durable, yet wax ribbons are (generally)not recommended for applications involving abrasion or prolonged chemical exposure. Many tags, signs, and bar-code labels are printed with thermal transfer printers.
Flexography. "Flexo" printing is the most common label printing method. Solvent, water and UV inks are available. Low cost plastic plates are used to transfer the ink to the label or tag surface. Many flexo presses allow the label manufacturer to print, laminate and die-cut the label in line, and this makes it suitable for longer runs of labels. Most flexo labels are sold in a roll form. Examples of flexo labels include labels on detergent, toothpaste and certain RTK labels and paper tags. Typically, Flexo printing is not used when either large areas of solid color are needed nor if the label must last outdoors.
Direct Thermal. In this process, the printer works like a thermal transfer printer, and selectively heats a coated plastic or paper label stock with resistive pins, to form a pattern. These base films have a specially coated surface that turns dark when exposed to high heat. Bar-coded airport labels used to track your luggage and UPS shipping labels are often printed with an indirect thermal printer. The printers are very inexpensive and this means portable thermal printers are increasingly common.
Ink Jet Printing. Ink jet printing is the fastest growing of all printing techniques. Problems associated with ink jet's speed and outdoor durability are rapidly being addressed. New pigmented inks that are replacing dyes promise greater outdoor durability.Overlaminates extend the chemical resistance and outdoor resistance of the printed images.
Laser Printing. Laser printer prices continue to come down and this means that more and more computers are attached to a local laser printer. The best laser printers for labels offer a straight paper path.Black toner, especially if protected with an overlaminate, has excellent outdoor durability. Overlaminates extend the chemical resistance and outdoor resistance of the printed images.
Screen Printing. Screen printing is the most durable of all printing techniques. This process "lays down" a very thick layer of pigment and this extends outdoor life. Both solvent and UV inks are common, with the UV inks imparting good chemical resistance. Most signs and pipe makers are screen printed. Other screen printed products include the design on a CD-ROMs, many automotive nameplates, the defrost screen on a car's rear window or the decoration on china plates.
Offset Printing. This is a plate-based printing method often used for paper tags.
Dye Sublimation. Heat sensitive sublimation inks are bonded to permanently dye substrates with polymer coated surface with desktop printers, similar to thermal transfer printers. Dye Sublimation is great for short-run custom designs, such as ID Badges, promotional mugs, mouse pads and T-shirts.
Engraving. This is a process that uses an engraving tool to mark office nameplates, trophies and awards. In general, a rotating diamond-tipped tool scratches lettering into metal or a two-ply plastic. For plastic signs, the core color, in a contrasting color, is exposed. Formica, in fact, is one of the materials that engravers use. There are a wide variety of common plastic engraving materials, including ABS, phenolic and acrylic laminates.
Hot Stamp Printing Hot stamp printing uses an etched printing plate, which is heated and applied under pressure to the backside of a coated ink ribbon (or stamping foil). The ink is melted and transfered to the surface of the label or tag stock. Hot stamp labels are very high quality, with very opaque and bright colors, holograms, metallic mirror , and other special effect prints. Recently, hot stamping equipment has been integrated with thermal transfer printers to enable serialization and random barcode information to be printed on graphic quality labels. Hot stamp presses also laminate, butt cut, perforate, and die-cut as required.
Question #2: Why does vinyl jam in a laser printer? Laser printers fuse at about 350 degrees F, which is hot enough to melt vinyl. Polyester runs much more smoothly in the laser printers.
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