By Melissa Donovan
Marking or coding inkjet devices are designed for high volumes and variable data. They handle high production speeds with fast drying ink, making them ideal for marking and coding a product’s packaging or the product itself.
“Codes can be changed on the fly, a real advancement over mechanical devices, because digital printing technologies make it possible to change variable date, time, and batching information dynamically and seamlessly,” says Mark Breunig, product manager, CIJ, Videojet Technologies, Inc.
Speed and variability are attractive to multiple markets from food and beverage to health and beauty, as well pharmaceutical and industrial. Products manufactured in these industries require a form of marking or coding that won’t impact the production line. Items as small as an electrical or cable wire to something as fragile and unwieldy as a light bulb are prime candidates for the digital print process.
Above: Electrical wires marked using the InkJet DuraCode CIJ printer.
A Non-Contact Sport
Inkjet marking or coding devices are considered non-contact, which means ink droplets fly onto the object in question without touching it. Inkjet printers continue to evolve since their introduction in the late 19th century. Both continuous inkjet (CIJ) and thermal inkjet (TIJ) are options for marking and coding applications.
In the 1970s, industrial inkjet printing for batch information came on the scene, according to Christian Krzykwa, associate product manager, Hitachi America, Ltd. “The core concepts remain unchanged, but the technology has improved to make it faster and more efficient.”
With marking and coding systems ink is ejected from the printhead in some way. “Some use electrically charged droplets, others use a crystal to squeeze out the drop, valves release pressurized drops, or some use a plunger to push the ink out,” explains Jon Jensen, canning and beverage section manager, InkJet, Inc.
Inkjet printing allows a single printer to mark a large variety of items. CIJ in particular, says Krzykwa, can print to hundreds of items per minute without being affected by minor variations in line speed or product orientation.
Fewer touches during the manufacturing process are ideal, and this is something a non-contact process provides. As Breunig shares, anytime you touch a product, there is a possibility of impeding that process or causing a jam, which slows down the production line.
“Inkjet printing has the benefit of not interfering with that core manufacturing process. Manufacturers have taken advantage of inkjet printing for over 40 years,” continues Breunig.
Not all coding technologies are contactless. Contact marking and coding equipment is defined as marking equipment having direct contact with the box or product during the coding or marking process. Some options include stencil machines, roller coders, contact coders, electrochemical marking machines, and dot peen systems.
Until inkjet print engines advanced, these were all viable alternatives. According to Jensen, the original inkjet systems only printed at a maximum of 50 dpi—which was very expensive. Today, these devices can print up to 600 dpi for less than $2,000.
These technologies remain dynamic. “Inkjet coding technologies continue to evolve with the introduction of cloud-based services to monitor performance and provide preventative maintenance services through additional features,” explains Philip Parkin, CIJ product manager, Domino Printing Sciences plc.
The Inkjet Advantage
Inkjet devices present advantages to the manufacturers that use them, with the biggest one being the ability to print to anything. Disadvantages that may steer users toward contact printing methods continue to be remedied as technology advances.
The most obvious benefit to using non-contact marking and coding devices is that “the printer/printhead does not touch the product, and therefore can’t damage the product in a way that contact printing methods can,” explains Breunig.
This gives inkjet coders the flexibility to print variable information like dates, batch numbers, or barcodes onto packaging substrates of different porosity, small and large sizes, uneven and varied shapes, or those with rough and smooth textures,” says Lance Carpenter, VP, Carpenter’s Time Systems.
Inkjet is also more tolerant of substrate movement compared to contact printing. “This is particularly true for CIJ where coders can print from a distance over ten millimeters from the product and produce quality printed codes,” shares Parkin.
“Any form of contact printing is much more susceptible to variability in material handling,” agrees Krzykwa.
While printing during movement—quickly—is inkjet’s strength, an inkjet device can only print while moving. “Every inkjet requires motion to legibly mark a substrate, by either product motion or moving the printhead—but lineal motion is a must. Some contact devices can mark while the product is moving and not moving,” explains Jensen.
A traditional disadvantage of inkjet involves adhesion. Traditionally, contact marking and coding devices featured better rub resistance on some substrates due to improved adhesion characteristics, according to Parkin. However, he believes this challenge is becoming less frequent thanks to continued advancement in CIJ technologies.
To remedy adhesion issues, many of today’s inkjet devices are able to use solvent-based inks. Jensen says this enables adhesion on a wider variety of substrates.
Another stigma attached to inkjet, specifically CIJ, is resolution. “CIJ is often referred to as low-resolution printing because it uses a dot matrix to create printed characters,” explains Krzykwa.
Main applications, industries, and users that benefit from inkjet marking and coding devices are unlimited, with the only real requirement related to efficiency.
“The food and beverage industry is the largest market segment for marking and coding technologies. Variability in package sizes, shapes, and materials requires a versatile product when it comes to secondary printing,” shares Krzykwa.
Speed is a consideration for why these sectors decide to use inkjet printing in their facilities. According to Breunig, the higher the speed and throughput, the more likely manufacturers will choose inkjet printing.
Parkin agrees, and offers examples like food, beverage, and industrial profiting from non-contact technologies. More specifically, he believes the pharmaceutical sector particularly benefits from TIJ. “It is easily integrated into existing production lines and can produce high-resolution codes at high line speeds for compliance with legislation for track and trace and serialization,” adds Parkin.
“Many products move at high speeds on continuous packaging lines. With most contact devices you need to stop—albeit briefly—to mark products. Stopping reduces throughput. If you tell a plant manager to stop the line to print, the plant manager will show you the door,” admits Jensen.
Carpenter states that all packaging and manufacturing industries benefit from inkjet coding and marking devices. “This is because of the affordable price point of this technology and the ease of setup and do it yourself installation.”
Some requirements that make a product suitable for inkjet marking and coding are if it is moving, fragile, has an irregular surface, or requires a fast dry time. Jensen suggests looking in the refrigerator—eggs, milk, butter, juice, soda, beer, salad dressing, the salad bag, probiotics, yogurt, and the list goes on down to the wires and lightbulbs in the refrigerator itself—these are prime candidates for inkjet marking and coding devices.
Inkjet printers work with a number of ink types from water to solvent. Choosing the right one should be based on the substrate being marked or coded.
Ink sets work best when used for their particular purpose and hardware. “Contact and non-contact printing devices use specific inks designed for optimum performance within their respective printing technologies. The ideal ink for any application is highly dependent upon the type of substrate to be printed,” stresses Breunig.
“CIJ uses specialized inks made to run well in the printer, minimize downtime, dry on contact, and have superior adhesion. For this reason it is always recommended to use the ink specifically designed for your printer and your application,” advises Krzykwa.
Jensen suggests looking at the substrates and processes as to what dictates the type of device and consequently ink required. For example, for inkjet alone, there are water-, oil-, or solvent-based inks or even electrically chargeable.
New advancements in inkjet ink technology come about in response to stricter regulations. “Inks are designed to adhere to almost any substrate even after harsh post-print processes, such as chemical wash downs or retort processing. This allows manufacturers to meet regulations around product safety and maintain supply chain transparency,” adds Parkin.
As with researching any product, there are specific hardware components and usage requirements a manufacturer should consider before investing.
On the hardware side, Breunig says generally speaking, inkjet printing requires less integration and product handling support hardware than a contact device does.
“Like adding any new component into a packaging line it can take some specialized engineering to maximize the efficiency of the product,” admits Krzykwa. However, CIJ printers are easy to setup compared to other forms of printing. “All that is required is an area where the material can pass by the printhead at a consistent speed and distance from the printhead.”
Jensen suggests interested buyers ask important questions prior to financially committing to a device. These include a focus on type and amount of maintenance. Will it be serviced by your own personnel or a specialist? Are the components field repairable? Do they have a lifespan that could stop production or are costly to replace? What is the cost of ownership over the lifetime of the device?
Mark and Code Anything
Inkjet is making significant inroads into the marking and coding community. Contactless by nature, it’s ideal for any product that needs to be marked or coded on a fast-speed production line. This includes irregular shapes, rough or slippery surfaces, and small or large in size.
Nov2019, Industrial Print Magazine