Water-based single-pass inkjet on corrugated cardboard: areas of application and practical use

Water-based single-pass inkjet technology is becoming increasingly popular for reprinting corrugated cardboard. This article explains how the process works, where it offers real added value, and what is important in terms of quality assurance and compliance with food contact regulations.

Water-based inkjet printing is becoming increasingly important for customising, quickly adapting or producing packaging in small runs. Applications range from e-commerce shipping packaging to shelf-ready retail solutions and seasonal or localised campaigns. As these areas of application grow in popularity, the process is becoming relevant for an ever-growing number of market participants.

The main equipment used is printing machines with single-pass piezo printheads and pigmented, water-based inks that print directly onto the corrugated board liner. Typical substrates include uncoated kraftliners, white top qualities and coated liners. In most cases, a primer is first applied to stabilise the shape of the dots and ensure accurate colour reproduction on difficult surfaces. This is not necessary for some uncoated liners, but is often essential for very smooth or coated materials. Secondly, the cardboard is dried and conditioned to control its moisture content during printing. Thirdly, an optional overprint varnish (OPV) can be applied if increased abrasion or chemical resistance is required.

Compared to preprinting, this approach reduces the logistical effort and waste associated with short or frequently changing jobs. Compared to analogue reprinting, printing plates are no longer required, and changeover times are significantly reduced.

The rise of e-commerce and customised retail formats has transformed the role of corrugated cardboard packaging: it has evolved from mere transport boxes to brand-defining touchpoints. Digital printing offers decisive advantages in this regard, including quick layout changes, short lead times, and the elimination of the need for plate storage. Digital solutions are also becoming increasingly important in the wider packaging market, particularly in situations where flexibility is required. The level of acceptance varies depending on the segment, but the trend towards digital processes is clear.

Hygiene and cleanliness are additional factors. Water-based systems are characterised by low emissions of volatile organic compounds (VOCs) and easy cleaning. UV systems can also be low in VOCs. However, for many companies, the use of water-based inkjet as a clean process fits well into existing corrugated board and finishing processes.

It is particularly useful for orders that change frequently or come in many variants. Examples include shipping cartons for online retail, shelf-ready packaging (SRP) with promotional updates and packaging that needs to be localised shortly before shipping, such as for language adaptations, mandatory labelling or retailer-specific codes. In such scenarios, the economic advantages of small print runs and quick changeovers usually offset the higher ink costs per square metre.

However, not every print image is ideal. For very large 'hero' designs or long, stable print runs, analogue printing or pre-printing is often the better choice. Therefore, water-based inkjet printing should be seen as a complementary tool wherever speed and flexibility are required without compromising performance.

Three factors are crucial for implementation: substrates, moisture and finishes. Uncoated kraftliners are absorbent, whereas white surfaces react differently depending on the weight and smoothness of the coating. Many companies compile a shortlist of approved liners and store ICC profiles for each liner/primer combination. This reduces surprises and shortens set-up times.

The next step is moisture control. Corrugated board is hygroscopic, so drying introduces additional heat. Maintaining a constant climate throughout the production line, in combination with carefully coordinated dryer profiles, helps prevent deformation and delamination, particularly with light or recycled liners. If deformation does occur, it is important to carry out a diagnosis before assuming that the print template is the cause. Are the initial moisture content of the plates, primer application, dryer set points and transport settings correct?

Further processing sets the boundary conditions. If higher abrasion or chemical resistance is required, inline or nearline OPV is worthwhile; it is essential to test this in relation to subsequent processes, such as die cutting, gluing, and applying adhesive tape. Since some adhesives behave differently on printed surfaces, conducting short production tests early on saves time later.

When it comes to colour management, pragmatism is preferable to perfectionism. Since kraftliner and white top offer different colour spaces, realistic target values for colour deviations (ΔE) should be set for each substrate. Brand teams appreciate side-by-side proofs that demonstrate what is reasonably feasible.

Costs also follow this logic: opacity influences ink consumption, while plant utilisation and material yield determine profitability. When budgets are tight, design teams can reduce large solid areas or control ink application. Operations focus on orders per day, operating time, and material yield (e.g. trimming and damage). Overall, these factors have a greater impact on profitability than individual specification details.

Aqueous inks are not automatically food-safe. Processors work within the framework of EU regulations for food contact materials and Good Manufacturing Practice (GMP). A standardised procedure is common, involving defining the intended use, collecting supplier documents, modelling worst-case migration, and carrying out targeted analytical testing where necessary.

It is important to distinguish between primary and secondary packaging. For transport packaging and SRP, printing is usually done on the non-food side, making evaluation easier. For direct contact, either a functional barrier is used or designs for very low migration are developed and validated.

From the perspective of many manufacturers, corrugated materials with water-based printing are generally compatible with standard fibre recycling processes, eliminating the need for deinking. However, two limitations should be noted: very high opacity or a high carbon black content can impair sorting in some systems. Special effects (e.g. metallic effects) should be coordinated with end-of-life partners before implementation. A brief design review with sustainability and procurement teams usually clarifies such issues at an early stage.

If the primer is specified too late, fluctuations will quickly occur. It is therefore advisable to treat the primer and liner as a pair and profile them together. Ignoring environmental conditions can result in streaking and deformation, so it is important to keep relative humidity and temperature stable. Treating kraftliner like coated material will disappoint when it comes to colour reproduction, so coordinate your goals with the brand teams at an early stage. Last but not least, monitor the behaviour after printing: check for cracks on folds, fibre dust, and the performance of the adhesive on printed surfaces

Primer chemicals expand the printing window and dryers are becoming more efficient, while inline inspection is becoming increasingly reliable on porous substrates. Analysts expect further growth in digital packaging printing in the coming decade, particularly for corrugated board. Systems that combine water-based inkjet printing with reliable quality assurance and clear application limits can economically handle small to medium print runs, freeing up analogue capacities for long, stable runs.

Water-based inkjet printing is ideal for reprinting corrugated board when quick changeovers, versioning and a clean process are important. Established risk management can ensure regulatory compliance, especially in connection with food, even for secondary packaging and compatible fibre streams. The best results are achieved by teams that control substrates and moisture, integrate further processing early on, and make good use of the system's capacity. Initially, it is advisable to define a shortlist of substrates on which colour and quality are stable, before gradually expanding the range of materials.