Oce 3121 Technical & Service Manual page 406

Detection of the trailing edge of the last document.
2
Copiers with a long feeding path (from cassette to drum) usually pick up copy
paper early. This is to speed up the copying operation. Copy paper is frequent-
ly picked up before the document arrives on the platen.
For this reason, the RDF is programmed to pick up a document at the same
time as the copy paper is picked up.
If the documents are 220 mm or less, the RDF feeds the second document past
the registration roller, after setting the first document on the platen.
T-O-T-S bar
Re-circulating bar
2nd document
2nd original
If the t-o-t-s bar is on a document, the RDF communicates to the copier the
presence of a third and subsequent document. This allows the copier to pick
up copy paper.
If the t-o-t-s bar fall through the aperture in the document tray, the RDF com-
municates to the copier the absence of a third and subsequent document. LDD
signal is ON. The copier not pick up copy paper.
Counting the documents
3
The number of documents do not need to be counted for:
- single-sided documents to single-sided copies
- two-sided documents to single-sided copies
- for two-sided documents to two-sided copies.
The RDF feeds the documents from the tray to the platen in a fixed sequence.
It must know, however, if the number of originals is odd or even when making
one sided to two sided copies. To enable this the RDF counts the originals
while the copier is at rest
ed.1 10 RDF 525