Blank page removal not working

I was given a quick fix for a scanner problem just now that is interesting. There is a feature on most copiers called blank page removal. While most users have never heard of it it is pretty obvious. When copying or scanning if the machine detects that a page has nothing on it (a blank page) then the machine has the option to remove that page to save paper or scanned file size.

Why would you copy a blank page? Double sided scanning mostely. If you scan two sheets that contain three pages so the last side is blank then you don't want a PDF file with a fourth blank image. Selecting blank page removal solves this. 

However we have a had a couple of machines with DF-701 dual scan document feeders that won't do this blank page removal. The DF-701 has a Contact Image Scanner built in so it can scan the back side of the page at the same time that the front side is scanned and thus doubling scanning speeds. However some of these CIS units don't calibrate correctly and pick up a shadow on all pages and reports that the page is not blank. The shadow does not show on any scans or copies but prevents the bank page removal from working.

I am sure a firmware update will come along to fix this but until then I was given a work around. If you go into the service mode and turn off CIS calibration under system 2 then the blank page removal will work fine. Just remember to turn the copier off and on after changing the setting.