Single sheet feeder
The single sheet feeder is a term from printing technology and describes a transport system for feeding sheets to sheet-fed printing machines .
With this system , the stacked sheets are lifted individually by several vacuum suction devices at the first incoming end and conveyed to the feed table by feed grippers or conveyor belts, where they are aligned using front and side marks . The separation of the uppermost sheet from the paper stack is problematic and is mainly solved by the combination of suction and blowing systems. Nevertheless, electrostatic charges occasionally lead to two sheets sticking together, so that so-called double sheets run into the machine. The clean separation of the sheets is important and is automatically monitored in the system area, for example by a double sheet control. With the single sheet feeder, the following sheet can only be picked up by the suction cups when the preceding sheet has completely left the system stack. As a result, the transport speed in the contact area corresponds approximately to the printing speed and the time for the sheet alignment at the front and side marks is extremely short. For this reason, the single sheet feeder is only suitable for low machine speeds of up to approx. 10,000 sheets / h and for smaller formats up to DIN A3. With the single sheet feeder, all paper thicknesses and also air-permeable papers can be laid out well, since blocking of the papers can be easily recognized.
An older type of single sheet feeder is the friction feeder , which works without increasing the vacuum. The counterpart to the single-sheet feeder is the stream feeder .
Individual evidence
- ↑ Helmut Kipphan (Ed.): Handbuch der Printmedien. Technologies and production processes. Verlag Springer, Berlin et al. 2000, ISBN 3-540-66941-8 , pp. 239f.