Dell C1765NFW MFP Laser Printer - Manual (Page 221)

Loading Print Media 219
Loading Print Media in the Priority Sheet Inserter (PSI)
NOTE: To avoid paper jams, do not remove the PSI while printing is in progress.
NOTE: Use only laser print media. Do not use ink jet paper in this printer.
1 Open the front cover.
2 Slide the PSI forward, and then align the PSI to the marking on the paper tray.
3 Adjust the paper width guides to their maximum.