subject: Coding And Marking Technologies [print this page] There are a wide range of coding and marking technologies to choose from when deciding how to place marks and other information on products or packages, each with benefits, dependent on the application.
Continuous ink jet (CIJ)
Continuous ink jet (CIJ) has become one of the most versatile and durable coding and marking options. Small character CIJ printers create lot codes, expiration dates, bar codes and graphics primary package marking, while large character CIJ printers do the same for secondary packaging such as cartons and corrugated boxes.
Small character CIJ delivers high-quality codes by applying a stream of ink drops via a printhead to the package. This allows codes to be applied in a variety of fonts, lines and direction and at a range of throughput speeds up to 1,000 feet/min. and with code heights ranging from 1/32-inch to more than half an inch.
Laser coding
Laser coding and marking can be used for marking numerical codes, 2D and linear bar codes, logos and symbols onto labels, sleeves, glass and plastic bottles, cans, kegs, tubes, blisters, cardboards, tubular films and caps.
Lasers do not require inks, stamps or ribbons to generate a code. In modern sealed-off CO2 laser coders, the infrared laser light is generated via radio frequency discharge in a carbon dioxide gas mixture. CO2 laser systems code thermally by changing the surface color, melting, foaming, or removing the material surface.
The advantages of laser coding include speed, versatility, code permanence, non-contact operation, clean and dry process, maintenance-free operation over thousands of hours, low operating costs and adaptability to a fully-automated line.
Thermal transfer overprinting
Thermal transfer overprinting (TTO) features a thermal transfer printhead and ribbon that makes contact with a flexible substrate, such as synthetic films and plastic labels. Miniature print elements under a glass coating heat small areas of the ribbon and transfer ink to the target substrate.
Typical applications for TTO are for package marking in the snack, bakery, meats and frozen food industries, where flexible packaging is common. There are also special applications, such as in the coffee and confectionery industries, where generic packaging is used and all product branding and specifications have been added using TTO.
Binary array ink jet
Binary array technology is a form of non-contact continuous ink jet printing that uses up to 256 orifices in the nozzle to generate more than 15 million droplets of ink per second, creating a curtain of ink. The printed image is controlled electronically by on/off (or binary) charge of pressurized droplets of ink.
A Binary array marking system prints high-resolution bar codes, text and graphics up to two inches high. Applications for binary array ink jet printing include printing variable information on pre-printed chipboard folding containers and labels; personalization of promotional mail packaging; security forms and serializing, lottery and gaming; plastic bottles; and compact disc jackets with artist name and serial number.
Thermal ink jet
Thermal Ink Jet (TIJ) printers use print cartridges with a series of small electrically heated chambers controlled by a flex-circuit. To produce an image, the printer runs a pulse of current through the heating elements, causing a steam explosion in the chamber to form a vapor bubble. This bubble propels a droplet of ink out of the nozzle onto a surface to form text, bar codes or graphics onto the substrate.
TIJ technology is ideal for coding requirements often found in the pharmaceutical, tobacco, health and beauty, and other industrial markets. These printers enable high-speed coding of serialized data and many types of bar codes, including GS1 DataMatrix, to be compatible with track-and-trace applications.
Making the choice
Careful consideration of the application is the first and most important step toward determining the right coding and marking technology for a companys needs. From there, supplier representatives can assist in taking the next step in examining the features and costs of specific marking system choices.
