What causes blocking?

Blocking can be caused by a number of things: poor ink drying before stacking, incorrect application of silicone or a stacking equipment that works with too high pressure.

 

How can I avoid blocking?

One of the first things to check is the drying process. Here are some actions you can take to make sure that your printed matter dries properly:

1

Pre press profile

Check that you are using the correct pre-press profiles for the printing method, paper and ink.

2

Ink/water balance

Check the ink/water balance.

3

Reduce ink film

Try to reduce the ink film if it is possible, less ink on the paper means less risk of blocking. 

4

Increase oven temp

Increase the oven temperature for faster drying. You can also reduce the press speed to allow for more drying time before stacking. 

5

Reduce chill roller temp

Try to reduce the chill roller temperature, but be careful and watch out for condensation when doing so. 

6

Adjust silicone application

You can also do adjustments to the silicone application. Try to reduce the silicone film thickness and check the ratio between silicone and water.

7

Reduce pressure in stacking

Finally you can try to do the following adjustments to reduce excessive pressure in your stacking equipment:

  • Reduce the strapping pressure
  • Reduce the clamping pressure
  • Reduce the pressure on any crush rollers within the stackers and in the copy transportation systems. 

 

If you still have issues with blocking after trying these measures please don’t hesitate to contact one of our Technical Support Managers, and we’ll do our best to help you find a solution.