ImageRunner 5570

hello John,
Glad to help. Your copier has 2 seperate sensing devices built into the machine that allows it to automatically recognize the paper size for trays 3 and 4. There is one unit consisting of 2 photo-interruptors that determine the length of of the settings of the paper tray,and a potentiometer that allows the copier to determine the width of the setting of the paper tray. The copier recognizes the paper tray settings automatically as you change them for trays 3 and 4. So there is really nothing required from you other than moving the side guides and the end guide to suite the paper size you wish to insert. The side guides are built into the paper tray and they move in tandem so when you squeeze the blue (I call it a clothes pin since it looks like one) release lever which allows you to change the paper width as you need. To the left of the tray there is a blue square block that is re-positioned as you choose to change paper sizes. This "end fence" should **** against the paper for support and there are markings at the base/bottom if the tray that indicate the proper postion it should be depending on the paper size you need to insert. I believe this pretty much covers it ! :-) Let me know if you need further help and have a great copying experience!!!!! LOL