The world of industrial printing is filled with diverse processes, each possessing its own unique specializations. While certain methods excel in printing books or artwork, only one is particularly well suited for printing barcodes and expiration dates: digital printing.
Although the category of digital printing includes methods like dye-sublimation and direct thermal printing, these approaches aren’t suitable for barcode/expiration date coding in an industrial context. For that application, inkjet printers, thermal transfer overprinters, piezo case coders are the optimal choices.
Consequently, this article will focus on which of these options are most suited for coding expiration dates and barcodes on primary, secondary, and tertiary product packaging. By differentiating between these three applications, we can analyze which machines are best for certain substrates and production line conditions, thus showing you which printer is best for your needs.
How to Code Primary Packaging
Primary packaging is what comes into contact with the product itself. Sometimes referred to as retail or consumer packaging, common forms of primary packaging include bottles, cans, packets, and wrappers. As primary packaging is customer-facing, it is often marked with barcodes to facilitate the purchase process, as well as expiration dates to meet industry/retail standards.
Just as primary packaging comes in a variety of forms, the range of materials used to create these packages is diverse as well. Glass, cardboard, metal, plastic, and paper can all be used to make primary packaging, and each of these substrates has unique properties that must be accommodated to ensure proper coding. Depending on substrate specifics and production line characteristics, organizations can pick one of these options to best meet their coding needs:
For High-Volume Applications: Continuous Inkjet Printers
Continuous inkjet (CIJ) printers are the go-to option for high-volume production lines. CIJ printers create continuous ink flows by pressurizing a mixture of ink and solvent that moves from a shared reservoir to an oscillating printhead.
CIJ printers’ highly pressurized inkjet system and large ink supplies make them ideal for fast, high-volume production lines. For example, DuraCode CIJ printers are able to print on products at a max speed of 1050 ft/min (320 m/min), with adjustable options to meet slower speeds as well. Additionally, CIJ printers can code both porous and non-porous substrates, as long as you use the right ink cartridges to match the material of your packaging.
For High-DPI Applications: Thermal Transfer Overprinters and Case Coding Printers
Both thermal transfer overprinters (TTO) and high-resolution case coding printers are two coding options that specialize in high-DPI (dots per inch) printing. High DPI capabilities are particularly useful to companies that must place barcodes or QR codes on primary product packaging, as barcodes require at least 200 DPI to be reliably scannable, while QR codes perform optimally at 300 DPI.
Thermal transfer overprinting is an optimal option for these applications as it can create full-scale 300 DPI codes. TTO models mark materials by pushing a ribbon from the printhead onto the substrate surface. The printhead consists of small heating elements that lie under a ceramic coating. The ribbon is covered with a mixture of either colored wax or resin. As the ribbon comes into contact with the heating elements, certain parts melt and transfer onto the substrate, leaving printed markings.
Case coding printers (also known as large-character printers) utilize high-density ink to create highly readable codes and graphics. The ink is propelled through a piezo printhead—a printhead that uses vibrations and electricity for printing. The controlled printing manner of piezo printheads in combination with high-density ink allows case coding printers to create high DPI codes. Additionally, certain case coding printers, such as the Precision 72, are equipped with large printheads, enabling them to create sizable graphics as well as other codes.
For Versatile Applications: Thermal Inkjet Printers
While CIJ printers are larger machines that are designed for stationary line placement, thermal inkjet (TIJ) printers offer a bit more flexibility. TIJ printers generally weigh only a couple of pounds and see usage ranging from bracket-mounted operation to handheld operation. Further, TIJ printers operate by using a system of easily removed ink cartridges, allowing you to switch between coding a nonporous material like plastic to printing on porous cardboard within minutes. It is also worth mentioning that each cartridge contains a new printhead, which is why TIJ printers require so little maintenance.
Although TIJ printers do not quite match the speed capabilities of their CIJ counterparts, machines like those found in the Anser series can still code at 120 m/min (394 ft/min), meeting the requirements of many lines.
How to Code Secondary Packaging
Secondary packaging is the other major type of packaging that requires consistent barcode application. Secondary packaging is what encases the primary packaging and is used to display and handle the product. For example, think of individual beer cans as primary packaging and the branded paperboard box that they are sold in as the secondary packaging.
Both primary and secondary packaging share many of the same substrates and coding requirements, so the machines used for primary packaging are still applicable here. However, that changes when we examine tertiary packaging.
How to Code Tertiary Packaging
Tertiary packaging is intended to keep products safe from physical damage as they are transported along the supply chain. Common forms of tertiary packaging include pallets and shrink wrap, neither of which require direct coding, as attached pre-printed labels are the preferred way to communicate needed information. That said, one form of tertiary packaging does often require barcodes: the brown cardboard box.
Cardboard boxes are one of the most frequently used shipping materials in the world, with over 100 billion boxes annually produced in the U.S. alone. To ensure that these packages make it to their rightful destination, many companies place scannable barcodes directly onto the box surface. However, the absorbent nature of corrugated cardboard can lower the readability of these codes, as can the brown color of the material.
Generally, CIJ printers are not able to print at a high enough DPI to ensure consistent scannability—eliminating them as a viable tertiary coding option. Conversely, many TIJ printers can code with a DPI of 600 x 300, a contrast level that is easily read by barcode scanners.
Additionally, high-resolution case coding printers, like the Precision Series 18, specialize in printing on porous substrates like cardboard. The high-density ink used by these machines ensures that the contrast level meets the needs of barcode readers, while their large printheads allow for a bigger text size than TIJ printers. Case coding printers, like those found in the Precision Series, can also be seamlessly integrated into an existing network, making them a great choice for an industrial operation.
Inkjet Printing: The Ideal Type of Industrial Printing for Barcodes and Expiration Dates
Inkjet printers are perfect for placing legible barcodes and expiration dates on your products and packaging. However, choosing the right machine to print these codes requires a close look at the materials that you are coding, as well as the unique qualities of your operation. You need a printer that not only can meet the surface qualities of your products but also fit into your existing production line setup. If you have any lingering questions about which printer is best for your needs, the experts at InkJet, Inc. are ready to help.