In a series of articles we will look at inkjet printing technology in several packaging segments. As a kick off we are looking at folding carton print – one of the most prominent segments in packaging.

The drivers

As in many markets, there is a shift in folding carton printing towards shorter runs and more just in time production. The reasons are numerous:

• More fragmented markets
• More brands
• Taking out inventory in the supply chain
• Reacting quickly on market demand
• Promotions
• Test marketing

The Corona pandemic propelled the desire to order on short notice. Manufacturers find their markets less predictable and need to react quicker. At the same time buyers want to keep less stock. The pandemic also gave rise to new forms of packaging, like to-go-boxes and trays. Being able to produce short runs makes these products available to many smaller restaurants and chains.

Improvements on the ordering side help as well. Web shops make ordering packaging more efficient for short runs and enable small companies looking into having their own packaging professionally printed.

There are some more advantages of digital print that become apparent in the process. Digital presses can speed up the colour matching for customers by finetuning colour values directly at the press. Conventional print might require going back into pre-press, remaking plates and starting up again. Less waste in the start-up improves the eco-footprint of packaging.

What to look out for

To a much higher degree than in document printing, the press format is a very important factor in folding carton print. If a box does not fit on the sheet, it cannot be printed. Even smaller box layouts can be more profitable on larger sheets, when nesting of complicated box layouts becomes possible. There are opportunities in small format folding carton printing, but the larger the format the more the range of applications increases.

Most users go for sheetfed presses, as substrates are quicker to change and waste is lower. The bulky material also means that rolls are depleted quickly or – if the board is heavy – the material might not be available on a roll. But do not count out roll-fed altogether, there are high volume applications for which it is well suited.

Special colours do play a big role in packaging print. On the one side, spot colours are often needed for certain product logos or artwork. Changing inks on an inkjet press is not feasible in daily production, hence spot colours need to be emulated by a fixed set of inks. Seven colour presses do have an advantage here but even CMYK inkjet presses have a wider gamut than standard offset process colour, allowing the emulating of many spot colours. More critical can be the usage of specialty inks such as white, metallic, fluorescent and the like. So far, inkjet presses would need a second pass with analog technology.

Inks

Inks are a key element in inkjet printing. Unlike commercial print it is not just the cost of ink, substrate suitability and food safety are major concerns as well.

Substrates for folding carton printing can be varied. Apart from the thickness, the surface finish plays a big role in printability. Since brands are looking for differentiation more elaborate gloss, matte and texture finishes  are becoming more widespread. Additionally, substates can be film or foil coated/laminated. Ideally the press should perform well on a wide range of stocks.

A major area of concern in folding cartons is food safety. A lot of folding carton is used in food packaging. Inks can contain hazardous substances that can migrate into the food. This even applies if the print is only on the outside of the package as substances can migrate to the opposite surface within a pile or roll of printed products. The EU is about to revise their regulations for food contact – so watch out for possible impact here.

Apart from harmful substances also the odour is important. Even if an ink passes the food safety test, the smell can impact the usability of a packaging. Pet food is said to have the highest requirements in avoiding odours, but many consumer goods are critical, reaching from food, to healthcare, tobacco and personal care.

UV inks are at some disadvantage compared to aqueous and even solvent inks, since by definition they contain monomers that are considered harmful. Thorough drying and careful selection of ink ingredients gave rise to low migration UV inks, although properties should be checked with the vendor.

Another option to improve the food safety properties is varnishing. This might be required for optics or handling properties anyway but does add an extra step and cost.

The equipment choice

The lack of inkjet adoption in folding carton is owed to a lack of press solutions available. Several devices were announced years ago and a few have made it into availability so far, but it has been a long drawn out process. This testifies to the high standard folding carton presses need to adhere to.

In the B2 format, Fujifilm with the Jetpress (JPress in the US) is used for folding carton printing. Both the Jet Press 720S and the 750S can be configured to take folding carton board by using a modified vacuum jacket and higher vacuum pressure around the drum. This allows the press to accommodate a more diverse range of heavier carton boards commonly used in packaging applications. There are a few pure folding carton printers deploying the Jetpress for folding carton print. More frequently commercial printers use the JetPress to complement their offerings with folding cartons.

The Konica Minolta Accuriojet KM-1 has been on the market for the last 5 years, mainly in commercial printing. The new KM1e announced in 2020 has greatly expanded its substrate management capabilities for a diverse array of applications – including folding carton board-stock. The press can produce applications on various types of media such as plastics, backlit signage, transparent film, foiled paper, metallic media, canvas and synthetic materials. The UV ink allows for a great substrate flexibility on non-absorbing substrates

In the B1 area, Landa with the S10 racks up the highest number of active installations in folding cartons with about 10 units to date. The single sided model S10 has been designed for folding carton print. The press sports seven colours for a wide gamut – covering 96% of the Pantone range according to Landa and has an analog varnishing/coating unit. Most presses installed already run 2 shifts with some already in 3 shift production.

Heidelberg with the Primefire withdrew from the market early in 2020. Heidelberg described the market as “not ready for inkjet yet”. However, the decision has to be seen on the background of drastic cost savings Heidelberg is executing now. Heidelberg deems it likely to enter the market again in the future.

About to launch is the König & Bauer VariJET 106. The press should have been running live at drupa 2020, but Covid brought some delays for the launch. König & Bauer is currently selecting the first beta customer and is expected to announce the company soon.

Scanning-head wide format inkjet can be used for folding carton printing as well. However, the low speed of the devices makes them only suitable for mock-ups and test marketing.

Outlook

The business opportunity for inkjet in folding carton is huge and growing. Part of growing the business is educating print buyers on the opportunities of on demand printing, which might involve remodelling their supply chain. It might require designing packaging without specialty colours as well, to take advantage of efficient short run and just-in-time printing.

The other part is having the right print technology, finishing and workflow. Pieces are coming together slowly.