What types of inks can you use in a continuous inkjet printer?

Continuous Inkjet (CIJ) printers are incredibly versatile when it comes to inks. One of their biggest advantages is the wide range of specialist inks available, designed to meet different materials, industries, and environmental challenges. Whether you’re printing on plastic bottles, metal cans, flexible film, or even eggshells – there’s likely an ink formulated to stick, stay legible, and stand up to your production conditions.

Here’s a breakdown of the main types of CIJ inks available – and what makes each one useful:

MEK-free ink

Most CIJ inks are solvent-based, and MEK (methyl ethyl ketone) is a common solvent for quick-drying performance. However, in some industries, MEK isn’t ideal due to regulations or safety concerns. MEK-free inks are a safer alternative with reduced emissions, making them more environmentally friendly while still offering good adhesion and drying speed.

Hard-pigmented ink

These inks contain solid particles (pigments) rather than just dyes. Hard-pigmented inks are used when high contrast is needed – like white ink on dark surfaces or for marking cables and wires. Because pigments can settle, these inks are used with printers designed to keep them properly agitated.

Fluorescent ink

Fluorescent inks glow under UV light, making them ideal for invisible or covert coding. They’re often used for quality control, anti-counterfeiting, or to track packaging during processing without visible marks.

Food-grade ink

Used in industries like bakery or egg production, food-grade inks are specially formulated to be safe for direct contact with food or edible surfaces. These inks comply with food safety regulations and are often made using ethanol or other food-compatible solvents.

Abrasion-resistant ink

In some environments, printed codes need to withstand scratching, scuffing, or friction – for example, during transportation or handling. Abrasion-resistant inks are engineered for durability, so your codes remain readable from factory to store shelf.

Sterilisation-resistant ink

In sectors like medical or dairy, products may be heat-treated or sterilised after packaging. These processes can fade or remove regular inks. Sterilisation-resistant inks are formulated to survive exposure to steam, heat, or chemical washdowns, making them ideal for coding on packaging that’s sterilised after filling.

Colour-change ink

These clever inks change colour after exposure to certain conditions, such as UV light or sterilisation. They’re often used as a visual confirmation that a package has gone through a specific treatment step – handy for quality control.

Water wash-off and alkali wash-off ink

These removable inks are designed for returnable packaging. After use, bottles or crates can be washed with water or alkaline cleaning solutions, and the code simply washes off – no need for scrubbing or labels.

So whether you need durability, safety, invisibility, or easy removal, CIJ inks are designed to match your production environment. Just make sure to pair the right ink with the right printer – many of these specialist inks are supported by the alphaJET CIJ range from Koenig & Bauer Coding, known for their flexibility and reliability.