tell me about the scanner insertion slot

The HP Designjet 815mfp is built so you can change the insertion slot height from 2 to 16 mm (0.08 to 0.63 inches). The Normal position (Step 0: 2 mm/0.08 in) is detected by a sensor in the scanner.

The original's insertion slot is marked with a measurement ruler for inches and millimeters. The ruler corresponds to right side aligned original loading. Just below the ruler are marked common standard sizes that help guide you with optional centered loading.

The loading method, right-side or centered, can be selected from the HP Designjet scanner software. The scan area width measured in standard sizes, inches or millimeters is also set from the application.

The required setting for an original drawing can be measured with the original inserted into the scanner by using the ruler printed on top of the insertion slot. Then, you just enter your measurement in the width setting box in the current scanner application's media size setup dialogs. To change the insertion slot height, see:

...how do I change the insertion slot height?