Common issues and their solutions in the printing process using intaglio water-based ink include

1. Clogging

Issue Description: Clogging, caused by the poor redispersibility of water-based ink, can lead to print quality problems such as pinholes, missing parts in small text, uneven ink coverage, and substrate show-through when handled improperly.

Remedies:

• For clogs due to intermittent shutdowns, specialized tools and cleaning agents should be used; severe cases may require plate removal and cleaning with organic solvents like ethyl acetate. A recommended practice is to keep the plate rotating during downtime.
• Rapid drying can be mitigated by adding 3-5% retarder to slow ink curing and adjusting diluent ratios (commonly alcohol-to-water 1:1 to 4:1), while cautioning against excessive water addition which can generate bubbles and incomplete drying.
• High viscosity ink should be appropriately thinned, balancing print speed and leveling, to prevent bubbles or degradation of image details from too low viscosity.
• Shallow cell depth necessitates deepening, but care must be taken as overly deep cells can thicken characters and blur fine details.

2. Plate Dirt Dragging

Issue Description: During water-based ink printing, especially around barcodes or dark graphics, residue ink due to inadequate scraping forms dirt streaks, an issue linked to the lower lubricity of water-based inks compared to solvent-based ones.

Solution Strategy: Ink manufacturers should incorporate additives to improve lubrication; printers need to adjust scraper angles and pressure, with shorter blades proving more efficient.

3. Inadequate Drying

Issue Description: Water-based ink dries slower than solvent-based ink, and insufficient drying results in roller adhesion.

Countermeasures: Elevating the drying temperature by 10-20°C, increasing ventilation, and, if possible, extending the paper travel path can help. Collaboration with ink suppliers for formula adjustments to enhance drying properties is also crucial.