Reducing the Curl in Printed Documents

If you live in an area that has high humidity, you might notice that your documents, printed through a laser printer, come out curled up. This happens due to the characteristics of the paper and the way in which laser printers work.

Paper has a tendency to absorb moisture from its environment. Paper shares two main characteristics with lumber (which shouldn't be surprising, seeing they are both made of wood). One characteristic is its moisture content, and the other is that it has a crown, or a natural bowing to it.

When paper is stored in an air-conditioned office environment, care should be taken that there is adequate ventilation around the paper, making sure that the paper is not directly in the airflow of the air vents. (Printers, as well, should not be placed over or next to an air vent. Condensation can form in the printer if moist air is continually blown through the printer itself.)

Paper has a natural tendency to bend in one direction, much like the crown in a long piece of lumber. If you open a ream of paper and loosely hold the stack of paper in the middle, it will sag on the ends. If you flip the stack over and do it again, you will notice a difference in the amount of sag. Depending on the paper path in the printer, you can take advantage of the paper's natural crown to help straighten the paper out as it travels though the printer.

Paper curls in laser printers because it experiences rapid moisture loss as the fusing rollers heat and press the ink into the paper. More heat goes to the side that the print appears on, less to the backside. That, combined with rollers that have small radii, causes the paper to stay curled.

Trying making sure that the paper is placed into the paper tray so it will be printed on the "crown" side of each sheet. The wrapper around the paper may also have markings that say "print this side." In this way, the natural curl of the paper counteracts—to a degree—the curl introduced by the fuser roller heating.

Also, some laser printers can be operated so the paper does not curl around several rollers. Usually this means opening a door on the back of the printer so the paper exits there and not on top. Check the user manual, especially for any details on how to print on heavy paper, card stock, or transparencies. Use this technique for your regular paper.

If your printer is an older one, it may help to get it services. Temperature controls on fuser rollers tend to degrade over time, and the fuser roller could actually be getting too hot. If you replace the temperature control mechanism (or the fuser roller itself), then the roller operates at a cooler temperature. The cooler temperature means less moisture loss on one side of the paper, and less curl.

Lastly, you can try keeping a small amount of desiccant in the paper trays and removing and storing the paper in the trays at the end of the day, and refilling them in the morning. If you store your paper in a cabinet, you might also try placing a desiccant in the cabinet with the paper. It will help absorb excess moisture so the paper doesn't absorb it.

WordTips is your source for cost-effective Microsoft Word training. (Microsoft Word is the most popular word processing software in the world.) This tip (3507) applies to Microsoft Word 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Word (Word 2007 and later) here: Reducing the Curl in Printed Documents.