| Offset Printing Technology |
 |
 |
The offset printing technology is at the moment the main printing technology. In the offset printing process the printing and non printing areas of the plate are pretty much on one level.The printing fields of the printing plate are oleophilic/ink-accepting and also water-repellent, that's, hydrophobic. The non-printing fields of the printing plate are hydrophilic, that's oleophobic in behavior. This effect is done by physical phenomena at the contact surfaces.
|
The dampening system spreads across the non-printing areas of the printing plate with a thin film of dampening solution.This dampening solution (water plus additives)distributes all over the non-printing zones. To realize good wetting, surface tension is required to be reduced by means of dampening additives. In extraordinary circumstances, reducing the surface tension of the solution too much may end up in too great an emulsification of printing ink as well as dampening solution, leading to a situation where a precise splitting up of printing and non-printing areas at the plate is not really achieved when inking.
The ideal offset printing process is dependent upon many chemical and physical details of the materials and components involved in the process. The most important are:
• Influence of the printing plate- surface tension of the ink-accepting places,- tension of the dampening solution accepting areas,- surface roughness, mainly of the ink-free/non-image surface,- producing methods in making the offset plate(mechanical or electrolytic graining, etc.);
• Influence of the inking rollers- qualities of the roller coverings,- surface tension of the roller material,- surface roughness,- concentric running;• Influence of the blanket- surface tension of the blanket,- surface roughness,- compressibility,- ink acclaim and ink transfer performance,
• Influence of the ink- surface tension, contact surface tension in relation to the dampening solution,- rheological properties (viscosity, tack, etc.),- dampening solution absorption/emulsification- running clean behavior at the time of start-up,- ink composition,- drying behavior;
• Influence of the dampening solution- water hardness/impurities,- dampening solution components (alcohol, detergents,buffer agents),- pH value, surface tension,- rheological features (viscosity, tack),- dependence on temperature of the rheological characteristics;
• Influence of the substrate- printability characteristics (smoothness, absorption capacity, ),- pH value of the substrate,- workability properties (tension/stretch behavior,picking, tearing);
• Influence of the printing press (on print quality and process stability)- design of the printing unit (accurate, stabilised, vibration absorbent, etc.),- make of the inking unit (front-heavy, back-heavy,free surface, little retroaction),- design of the dampening equipment (contact dampening,non-contact dampening),- design of the ink feed system (ink metering)
Article Source: http://EzineArticles.com/6739250
About Us
We at coasterdimensio.com, provide you all information about printing world like business cards, booklets, brochures, envelops, catalogues, letterheads etc.
|
|
Services
We are known for our best quality to provide our customers the exact and timely information they are in need of.
|
|
| |
| Articles |
|
| |
|
| |
Contact
You can reach to us through our email. Send us your queries and we will get back to you with in 24 hours.
Email: webmaster.contactmail@gmail.com |
| |
|
|
