ROLLERS ACCORDING TO PRINTING SYSTEMS
The rollers to be used for sheet offset printing systems are manufactured according to the offset printing requirements. The technical parameters for rubber rollers to be used in offset printing systems as identified by printing machine manufacturers are taken as basis. Therefore the technical properties of the rubber rollers found in every make and model are recorded.
ROLLER APPLICATIONS ACCORDING TO THE INK TYPES
Rollers with various properties are required for application of various ink types such as conventional, UV, Hybrid, etc with various properties. Choice of rubber tob e used fort he type ink tob e applied increases the performance oft the operation and usage life oft he roller. Rollers are choosen according to 3 different ink group applications;
Application of Conventional Ink
As the conventional inks are oil based, the rubber tob e used shall be oil resistant. Conventional ink is widely used in offset printing systems. Usage of suitable wash solvents extends the usage life of the roller.
Application of UV Ink
As UV inks consists acrilite, rubber with different structural properties is required.
Wash solvents that will not damage the rubber's structure shall be applied for cleaning of UV ink.
Application of Mixed Ink
Aynı makinede (merdanelerde) hem UV, hem de konvansiyonel mürekkep kullanılarak çalışılmak istenildiğinde merdane için iki parametre önem taşımaktadır.
FIRSTLY: Ratio of UV usage. If;
80 % conventional, 20 UV=> conventional rollers can be used.
>20 % UV=> mixed type (UV MIX - 371) roller shall be used.
Secondly: Usage of wash solvent that affects the roller the least. Some of the UV solvents can cause swelling, softening, aggravation due to the agressive structure of the solvent.
The existing conditions shall be considered for determining the operation rates. For instance; if the UV usage rate will not exceed 20%, mixed rollers shall be choosen for just in case purposes. The roller type to be choosen according to the ink usage rates affects the performance of the application.