Blocking

Blocking in printing refers to the undesirable adhesion between printed sheets, causing them to stick together. This often occurs when the ink is not properly dried or cured, resulting in the transfer of ink from one sheet to another.

Synonym

Sheet sticking

Examples

1. Commercial Printing: After a batch of brochures was printed, the printer noticed blocking because the stacks of paper were not allowed enough time to dry.
2. Packaging: Blocking can occur in packaging materials if they are stacked before the ink or coating has fully set, leading to damaged graphics and text.
3. Art Prints: Fine art prints can suffer from blocking if they are packed too soon after printing, causing the intricate details to be marred by ink transfer.

Recommendations

• Proper Drying Time: Allow adequate drying or curing time for printed materials before stacking or packaging them. This is especially important for jobs with heavy ink coverage or coated papers.
• Use Anti-Blocking Sprays: Anti-blocking sprays or powders can be applied to the printed sheets to reduce the risk of sticking.
• Optimal Storage Conditions: Store printed materials in a cool, dry environment to facilitate faster drying and prevent humidity from causing blocking.
• Paper Selection: Choose paper with appropriate coatings or finishes that resist blocking, especially for high-ink applications.
• Quality Inks and Coatings: Use inks and coatings designed to dry quickly and resist blocking. UV-curable inks, for example, cure instantly under UV light and are less prone to blocking.

Understanding blocking and taking proactive steps to prevent it ensures that printed materials maintain their quality and appearance. Learn more by contacting AP&B!