Dan Aykroyd and Bill Murray weren't called in for a "Ghost busting" exercise recently as a special Task Force mounted a search and destroy mission for "ghosts" of a different sort.

The ghosts this group of Postal Service and corporate experts focused on occur when modern laser-printer technologies come together with high-speed mail handling equipment causing a "ghosting" or mirror image to appear on some mail pieces.

The Task Force found that the printer's plastic toner material, which a laser melts to form the print on a letter, actually breaks or shatters when stressed by moving through high-speed mailing equipment that use pinch belts and metal rollers on long, serpentine paths. Fragments of the broken material then transfer to any paper surface in contact with the original image, forming the "ghost" image.

Although the Task Force didn't find a definitive solution, it did develop a set of guidelines that, if followed, should reduce or eliminate the majority of "ghosting" problems. They are:

• Always use the manufacturer's brand of toner;
• Use good quality laser paper with a basic weight of 24 pounds, a thickness of 4 to 4.7 thousandths of an inch, and a smoothness rating of 100 to 150 Sheffield units;
• Avoid sending self-mailing letters, as envelopes significantly reduce the chance for ghosting;
• If possible, pre-barcode and pre-sort all envelopes prior to inserting letters;
• Avoid text on text contact whenever possible; and
• Avoid putting laser-printed mail in collection boxes or down collection chutes.

The Task Force consisted of USPS engineers and mail preparation specialists and industry technical representatives from Xerox, IBM, Kodak, Hewlett Packard, Siemens and Larry Anderson Associates, Inc. More information can be found in the "User Guidelines for Letter Mail."

Postal customers experiencing "ghosting" problems should consult with their laser printer manufacturer for their latest specifications. Customers also can request assistance in testing for optimal paper, toner and printer settings by contacting the USPS. Direct inquiries to:

Manager, USPS Engineering -
Sortation Systems
8403 Lee Highway
Merrifield VA 22082-8101