As manufacturers aim to meet the increased demand for product identification and brand protection, they are turning to coding technology for use in their factories and throughout their supply chain.
There are many different coding technologies, all with their own advantages and challenges. When choosing the best coding technology for your industry, you need to consider many factors. These include: the type of material, the industry environment, the desired speed of application, and the print quality.
Here is a closer look at three coding technologies – continuous inkjet technology (CIJ), thermal transfer overprinting (TTO); and hot melt inkjet technology.
Continuous inkjet technology (CIJ)
One of the oldest inkjet technologies in use, CIJ involves sending a continuous stream of ink at high velocity through a nozzle, where the stream is broken down into tiny droplets of ink. The droplets are then charged selectively and deflected onto the substrate to print dot matrix characters. Undeflected ink droplets are recirculated and returned to the ink tank to be recycled.
CIJ can be used to print code onto almost any material, regardless of porosity, size, shape and texture. A major advantage of CIJ is the very high velocity of the ink droplets. This allows for a relatively long distance between printhead and substrate. Another advantage is the very high drop-ejection frequency – allowing for high-speed printing.
The solvent ink base allows for quick drying, which makes the CIJ ideal for products on a moving production line. The printing is precise and durable, and there are a variety of ink types and colours.
Thermal transfer overprinting (TTO)
Thermal transfer overprinting (TTO) is a digital printing technology that is gaining widespread recognition as a replacement to older analogue technologies, such as hot stampers. The technology has been engineered to work specifically on flexible substrates.
In TTO, a thermal printhead is used to transfer the ink from a wax/resin mix- or resin only-coated ribbon to the substrate.
A TTO printhead has small resistors that heat the print area precisely and with a fast on/off action. It is therefore not in contact with the substrate long enough to damage the packaging. TTO is ideal for printing on virtually all flexible materials such as plastic, foil films or paper labels. It can also be used on more delicate materials such as low-density polyethylene shrink wrap.
Thermal transfer overprinters can operate in two modes depending on how the printhead is moved relative to the ribbon and substrate. This is useful for packaging lines that may require intermittent or continuous printing.
Print elements are programme controlled to create digital, real-time images. Thermal transfer overprinters are freely programmable and can generate variable data such as time stamps and unique codes for every package. The high-resolution thermal printhead enables clear printing.
The latest technology in TTO uses only a minimal amount of ribbon, making thermal transfer overprinters an economical solution.
Hot melt inkjet
Hot melt inkjet technology has changed the face of coding technology by offering an alternative to CIJ technology.
In hot melt inkjet technology, a solid, wax-resin-based ink block gets melted internally. The ink is then expelled from nozzles by piezoelectric action.
The ink solidifies instantly on impact with a substrate, unlike water-based inks that rely on evaporation of a solvent for drying. As the droplet solidifies quickly, the final spread diameter and height of the droplet can be better controlled. This results in well-formed characters and codes. Unlike CIJ and TTO coders, the hot melt inkjet ink adheres securely to virtually any substrate without weeping.
The inks are solid at room temperature, allowing them to be picked up with no special handling requirements. Replenishing the ink supply is both a simple and clean task. As ink is melted internally by the system, there is no spilling.
Hot melt inkjet technology does not use chemical solvents or water. It is therefore more environmentally friendly.
Choosing a coding technology
Ultimately, when deciding on a coding technology, the strengths of each must be matched with how well it will integrate with other equipment on the line. It is critical to match the production line communications with printer capabilities, as well as ensure that the printer has the ability to process the information and print at the speeds necessary to meet production demands.
Pyrotec PackMack offers the latest coding equipment from our principals – international industry leaders Markem-Imaje, ALTech and Harland Machine Systems. Our team of experts offer technical and support services including maintenance, installations, training, service level agreements and advice on which technology is best for your applications. For more information, email us today.