Wet-on-wet printing
Important information has to be clearly readable. This is a challenge on smooth surfaces and transparent and dark substrates. Labels were therefore always well suited to packaging made of smooth plastics or foil - especially on transparent or dark materials. It was also preferable to print important data on metal products, such as drywall profiles, on a label that was then applied. Wet-on-wet printing using high-resolution inkjet printers and a resolution of up to 600 dpi for codes, text and logos.
In wet-on-wet printing, two or more colors are printed in immediate succession - without any drying time in between. Colored fields, codes and plain text are thus printed in a single work step. First, the colored field is applied, which is printed with important information in the same step - either with black or colored ink, but always in high resolution. The colored field and marking then dry together in a very short time.
This innovative wet-on-wet printing process neither limits production output nor affects the readability of the printed image. Quite the opposite. The previous drying time is no longer necessary, printing takes place in a single step and the contrast is optimal. The new printing process therefore enables a high first-pass reading rate for 1 and 2D Codes, text lines and logos with variable information such as date, time, counter, shift code and database content.
Which coding and marking system is used to implement this printing technology?
High-resolution inkjet printers and inline print control
Innovative wet-on-wet printing is implemented with the REA JET HR Inkjet Printer. With HP cartridge technology and a resolution of up to 600 dpi, it prints codes, texts and logos in a single work step - in direct succession, without interruption or drying time. Thanks to the use of newly developed inks, smooth or transparent surfaces such as foils, plastic or metal can be marked cleanly, environmentally friendly and solvent-free. The result is high-contrast, clearly readable, permanent and all this at high printing speeds.
Each print head produces print images with a height of up to 12.7 millimetres, and several print heads can be cascaded for images up to 50.8 millimetres high.
Hot swap function
The "hot swap function" enables cartridges to be changed during operation. As each cartridge is supplied with a new print head, the system is maintenance-free, ensuring uninterrupted product marking. Heatable print heads ensure consistently high print quality even in cold production environments.
Inline printing process
The wet-on-wet printing process can be ideally combined with the innovative REA inline OCR solution: Mounted above the conveyor belt and equipped with powerful optical text recognition (OCR) software, a camera system reads markings and codes on the passing product packaging and verifies them for accuracy. Capture and complete evaluation are completed in the shortest possible time, at just 70 milliseconds per print element. Fully integrated into the production and packaging process, it ensures that only fully and correctly labeled goods are delivered.
Wet-on-wet application in action
What are the advantages of wet-on-wet printing?
Well readable, high-contrast and abrasion-resistant
- No bottlenecks in material supply and therefore no production downtime, delivery capability is maintained
- No expensive downtimes due to set-up times when changing products, changing label rolls or changing carton layouts
- Economical ink consumption
- Higher printing speed
- Permanent, and therefore no peeling of the print or poor adhesion
- Single-origin disposal of the printed packaging promotes the recycling rate
- Cartridges can be changed during operation
- Reduced waste due to elimination of label backing paper
- Adhesion even on oily surfaces
- Low maintenance costs
- Lower printing costs per printer
