Inking Systems for Waterless Lithography
Waterless lithography requires a printing press that is equipped with a temperature control system, Figure 3-8. Two types of press temperature control systems are used: an ink oscillator cooling system and a plate cylinder cooling system. With the ink oscillator cooling system, a standard inking system is used with the exception that chilled or heated water solution flows through hollow vibrator rollers on the press. These temperature control systems allow the press operator maintain ink temperature within a narrow range of only a couple of degrees. Some water-cooled oscillators are single-ended, with water inflow and outflow at the same end of the roller. Others are double-ended, with the water inflow at one and end outflow at the other. Double-ended oscillators cool more uniformly across their width.
It is not unusual for each of the waterless inks on the press to perform best at a slightly different temperature. For example, a black ink might operate best at, say, 72~74°F (22.2~23.3°C), while a cyan might operate best at, say, 68~70°F (20~21.1°C). Terefore, the temperature of each inking system is independently controlled by using a zone control unit that blends hot and cold water to the proper temperature for the ink being used. In addition, infrared sensors monitor the temperature of each printing unit, providing immediate feedback to maintain the proper temperature level.
| 0 Comments |
|---|