When an HP LaserJet or OfficeJet with automatic duplex prints one side only, the job setting, paper path, or duplex unit sensor is usually at fault — not the toner.
Confirm duplex is available
- Many “n” models have no auto duplex. “dn”, “fdw”, and most “dw” units do
- In the app Print dialog, set Print on both sides / Duplex to Automatic (not Manual)
- In Windows printer preferences, enable two-sided printing and set binding (Flip on long edge for most documents)
Fix the paper path
- Use plain Letter/A4 20–24 lb paper. Labels, cardstock, and glossy often force single-sided
- Close the rear door fully. An open rear door or loose duplexer defeats automatic two-sided print
- Clear any scrap from the duplexer. A partial jam can leave the unit in single-side mode — see paper jam
- If tray 1 / multipurpose feeds but duplex fails from tray 2, test from each tray after a panel config page
Driver vs hardware
A basic Windows IPP driver may ignore duplex. Install the HP full feature or Universal Print Driver for your model. If duplex still fails after a successful one-sided print and a clean path, the duplex unit or sensor may need service.
Related: not printing and pick motor stalled.
Still stuck on one side?
Call (888) 423-7757 — available 24/7.