Almost all large presses have either a flying paster or a zero speed splicer. Both accomplish the same task for the pressman: allowing the web press to continue running without stopping or slowing down. Flying pasters are generally used on higher speeds presses.
Most modern flying pasters are equipped with a roll stand, dancer roller, metering roller, splicer and web guide. While some of these systems are used to operate as a separate part of the press, press manufacturers are integrating these into one unit. Here is a breakdown of each component.
1. Roll Stand
This part of the flying paster cares for mounting and holding the rolls in position. Nearly all flying pasters can hold two or three rolls at any given time - one running with two ready to splice.
2. The Dancer Roll
The dancer roll is otherwise known as a floating roller for its ability to move freely and pull the paper off the roll as it unwinds. Its sole purpose is to control the brake holding the roll. It thus controls the amount of paper released from the roll while maintaining tension between itself and the roll.
3. Metering Roller
It is very important in web offset printing to provide consistent tension to the press. While the dancer roller does provide tension, it is the metering roller's responsibility to provide consistent tension to the web press. It "meters" or governs the amount of paper being fed to the press through a nip point.
4. Web Guides
Each roll must line up with the printed product as it enters the press. The web guides perform this task. Sensors on each side of the web tell the pressman exactly where the roll is located. The pressman can adjust these sensors and the flying paster will move the roll accordingly.
The splicing mechanism itself joins the moving/expiring roll to the new one by means of a special piece of two-sided tape. The mechanism itself waits until the roll has reached the speed of the press and at the right timing presses the expiring roll onto the tape and immediately afterward cuts it. Timing and speed are everything in this process.
The entire process requires careful setup by the pressman so that all components can work properly: careful roll inspection, transport and setting of the splice.
Click here to see how a flying paster works.