hp laserjet pro m234dwe printing with weird streaks and smears all over the page

Diagnosis

Vertical streaks, horizontal bands, or random smears on the HP LaserJet Pro MFP M234dwe are typically caused by a failure in the imaging process, specifically within the toner cartridge (HP 136A/X) or the fuser assembly. When you see a consistent vertical line, it is usually a "scratch" on the organic photoconductor (OPC) drum or a piece of debris stuck to the cleaning blade. This prevents the drum from being wiped clean, leaving a trail of residual toner that transfers to every single page.

Smears or "ghosting" (where an image repeats further down the page) indicate a fuser failure. The fuser uses heat and pressure to melt the toner into the fibers of the paper. If the pressure rollers are coated in leaked toner or if the heating element is uneven, the toner doesn't bond correctly and smears as the page exits the machine. You can confirm this by touching the smear; if the toner wipes off easily with your finger, the fuser is not reaching the required temperature or pressure. If the smear is a physical indentation in the paper, there is a foreign object trapped in the paper path.

How to Fix It

To resolve these artifacts, you must perform a deep systemic cleaning of the internal imaging components.

1. Access the Embedded Web Server (EWS): Find your printer's IP address from the control panel. Enter this IP address into a web browser on a computer connected to the same network.
2. Execute Fuser Cleaning: Navigate to the System tab, then select Service. Locate the Fuser Cleaning Mode section and click Start. This will run a series of high-heat cycles designed to melt and clear debris from the pressure rollers.
3. Execute Cartridge Cleaning: In the same Service menu, find Cartridge Cleaning Mode and click Start. This rotates the drum at high speed to clear loose particles from the cleaning blade.
4. Physical Drum Inspection: Open the front door and remove the HP 136A/X toner cartridge. Carefully inspect the green/blue cylindrical drum. If you see a physical ring of toner or a scratch on the surface, do not attempt to scrape it with metal; use a dry, lint-free microfiber cloth to gently wipe the surface.
5. Paper Path Purge: Load 10-15 sheets of heavy-weight cardstock (approx 160g/m²) and print a few blank pages. The stiffness of the cardstock helps "scrub" the fuser rollers and pull out any trapped dust or paper fibers.

If That Didn't Work

• Replace the Toner Cartridge: Because the M234dwe uses an all-in-one cartridge (toner and drum in one unit), a failed cleaning blade or a scratched OPC drum cannot be repaired. Replace the unit with a genuine HP 136A or 136X cartridge. If the streaks disappear with a new cartridge, the previous unit had a hardware failure.
• Inspect the Transfer Roller: Open the printer and look for the small, spongy black roller located beneath the toner cartridge slot. If this roller is coated in dust or toner spills, it will cause light vertical streaks. Gently clean it using a can of compressed air or a vacuum with a soft brush attachment.
• Check Paper Settings: If smears occur only on specific paper types, go to Settings > Paper Setup and ensure the "Paper Type" matches the actual media (e.g., change from 'Plain' to 'Bond' or 'Heavy'). Incorrect settings result in the fuser not heating sufficiently for the paper thickness, leading to smears.
• Fuser Assembly Replacement: If you see a consistent, repeating horizontal smudge every 3-4 inches, the fuser film is likely torn. This requires a professional replacement of the fuser assembly, as this part is not user-serviceable without specialized tools.

Heads Up

• Avoid Non-HP Toner: Third-party cartridges often have inferior cleaning blades that leak toner, leading to the exact streaks and smears described above.
• Use High-Quality Paper: Cheap, high-dust paper creates "paper lint" that accumulates on the fuser rollers, causing ghosting and grey streaks over time.
• Never Touch the Drum: Avoid touching the shiny green/blue cylinder of the toner cartridge with your fingers; skin oils attract toner and create "spot" artifacts on every page.
• Keep the Environment Clean: This model is sensitive to airborne dust. If used in a dusty workshop, run a cleaning page weekly to prevent debris buildup on the optics and rollers.