The stain problem is mostly caused by the dried paint coming to the image part of the cliché. Causes and solutions:

Causes of Pad

• If the pad is too flat, a more tapered pad should be used.
  If the bumper is worn and rough, the bumper should be replaced.

Causes of Printing Block

• In case the cliché depth is not sufficient, a deeper cliché should be prepared and printed.
• If a wrong type raster is applied to the cliché, a cliché with a suitable raster should be prepared.

Causes of Ink

• If the ink dries in the cliché cavities, it should be cleaned with cliché thinner.
  If the ink is too thick, thinner should be added.

Material-Related Causes

• The material may be contaminated with oil: the material surface should be cleaned with alcohol.

Other Reasons

• If the printing speed of the machine is low, the printing speed should be increased.