Pages come out of the laser printer curled at the edges or rolled into a tube, making them hard to stack, staple or feed through again. Curling happens because the fuser heats the paper and drives out moisture unevenly, so one side shrinks more than the other. Damp paper, a paper setting hotter than needed and the curved path to the top output tray all make it worse. This guide covers simple changes to paper, settings and the output path that usually solve it.
What you might be seeing
- Printed pages curl upward at the edges or corners
- Sheets roll into a tube in the output tray
- Curl is worse on double-sided prints or humid days
- Curled pages jam when fed back in for a second pass
Common causes
- Moisture in the paper
- Paper that has absorbed humidity loses it unevenly in the fuser and curls as it cools.
- Too much heat for the paper
- A thick or heavy setting applies more heat than thin paper needs.
- Paper loaded on the wrong side
- Paper carries a slight natural curl from the ream, and printing on one side exaggerates it.
- Curved output path
- Pages heading to the top tray bend around rollers while still warm and keep that shape.
- Light or unsuitable paper
- Thin paper, and paper not designed for laser printers, curls more easily under heat.
How to fix it, step by step
Work through these in order and test a print after each one. Most people are done within the first few steps.
The fuser and the area behind the rear output door get hot during printing. Open the rear door before you print and keep fingers away from the inside.
Flip the paper stack over
Take the paper out of the tray, turn the stack upside down, and reload it so the printer prints on the other side. Many reams mark the preferred print side with an arrow on the wrapper. Because paper carries a slight curl from the ream, printing on the opposite side lets the heat counteract it instead of adding to it. Turning the stack end to end can also help.
Load fresh paper from a sealed ream
Paper starts absorbing moisture as soon as its wrapper is open, especially in humid rooms. Replace what's in the tray with sheets from a newly opened ream, and load only what you'll use in the next few days. Fold the wrapper closed around the rest of the ream and store it flat in a cupboard rather than on a windowsill or floor.
Match the paper type setting
Make sure the paper type in the driver and on the control panel is set to plain or thin for ordinary paper, not thick or heavy, which raise fuser temperature and add curl to light sheets. Some printers have a curl reduction option in the paper or maintenance menu; turning it on adjusts fusing to reduce curl, sometimes at a slightly slower speed.
Use the straight-through output path
Many laser printers have a rear door that doubles as a face-up output tray. Opening it lets pages leave straight out the back instead of bending around rollers on the way to the top tray, which reduces curl, especially on heavier paper and envelopes. The area behind that door gets hot, so open it before printing and keep your fingers out.
Try a heavier laser paper
If thin paper keeps curling, switch to a slightly heavier paper made for laser printers. Heavier sheets resist curl and hold their shape as they cool. Stay within the weight range in your manual and change the paper type setting to suit. Paper labeled for laser or multipurpose use is designed to cope with fuser heat.
Lower the room humidity
If curl is worse on damp days or in a basement, humidity is the root cause. Keep the printer and paper in a drier part of the building, away from humidifiers, kettles and open windows. A dehumidifier in a very damp room benefits the paper, your prints and the printer itself.
Flatten pages that have already curled
Let curled pages cool completely, then stack them under a heavy book overnight; they usually flatten well. Don't iron or heat them, which can soften the toner and make it smear. For future jobs, collect pages from the output tray soon after printing so the weight of later sheets doesn't set the curl.
How to keep it from happening again
- Keep reams sealed and stored flat until needed
- Load only a few days' worth of paper into the tray
- Note the print-side arrow on the ream wrapper
- Use the rear output for heavy paper and envelopes
Common questions
Why does curl get worse with double-sided printing?
The sheet passes through the fuser twice, losing more moisture, and the first side is reheated while the second is printed. That uneven heating increases curl and can cause jams as the curled sheet re-enters the printer. Fresh, dry paper and a curl reduction setting help most here.
Does a curl reduction setting slow printing?
Often slightly. The printer may lower fuser temperature, change speed or add a gap between pages so each one cools before the next arrives. The difference is small for most home and office jobs, and it's worth it if curled pages are causing jams or untidy stacks.
Is curling a sign that the printer is faulty?
Rarely. Some curl is a normal result of heat and moisture in paper. It's a concern if curl suddenly gets much worse with the same paper and conditions, or comes with smearing or wrinkles, which can point to a fuser problem. In most cases, paper and settings fix it.
This guide is general information written for common home and office printers. Menus and button names vary between models, so check your printer’s manual where a step differs. Printer Problems Solved is independent and not affiliated with any printer manufacturer. See our disclaimer.