Roller Maintenance16 Januari 2013
By vlad682000 On 07/11/2011 ·
For cleaning the rollers it is recomended:
1. Use a water miscible wash to remove the top layer of solvent-soluble and water-soluble particles from the nap of the roller.
2. Use a non-grit roller paste to remove the insoluble particles.
3. Finally, wash a second time with a water-miscible wash to remove the remaining soluble particles.
Glazing – Over time, rollers pick up particles from the ink, the paper coating and the dampening agent which block their pores. This contamination results in a smooth shiny surface. Inappropriate detergents and hard water contribute to this effect. Transfer of ink and dampening solution is noticeably inhibited as a result.
PROBLEMS – A worn out roller, a roller with damaged bearings, rollers set with too much pressure or, a roller that has not been properly cleaned, can cause:
* color inconsistency
* poor solids, or mottling
* dirty print
* excessive dot gain
Besides the obvious costs of poor print quality, including wasted paper and ink, bad or poorly maintained rollers can cause excessive press downtime, increased running costs, and shorter roller life.
If possible, do not expose rollers to direct natural or artificial light.
• The special paper that the rollers come delivered in prevents light penetrating and therefore helps retain the rubber’s characteristics. For this reason, do not remove the paper before inserting the roller in the printing press.
• Always put the roller with its pivots on a frame support: Putting it down directly onto the rubber can result in permanent deformations (pressure marks).
• Store rubber rollers in a cool and dry place.
• Under certain circumstances ozone causes microscopic scratches on the rubber surface. For this reason do not store rollers in the vicinity of motors or other electrical devices.