Document feeder not always working

[terp]

I have a Brother MCF-7840W printer. I bought this used to replace the same model purchased new. I was able to get all functions to work except the fax. I can send a fax one page at a time by placing the page directly on the glass. If I put a sheet on the feeder tray, it recognizes its presence because the display changes with a prompt to enter fax number. However, the feeder will never feed the paper and the fax sends a blank page. If I scan from the feeder, the feeder works fine. Any ideas on what to do?

 

[terp]

One additional piece of information I neglected to include: with my previous all-in-one printer, if I sent a fax by placing the page directly on the glass, after scanning that page, it would prompt me if I had an additional page. This printer does not do that and just sends the one page and stops. There must be a setting for this sort of thing, but for the life of me, I can not find it.