Laser Printer Deposits Toner Spots on Printed Pages

By Elizabeth Mott

Problem printouts signal a printer problem or a problem printer.
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An office laser printer that emits spotted printouts may leave you wishing for the hardware equivalent of pimple cream. These kinds of output defects waste your paper, toner and time, and then call on your investigative skills to resolve them. Fortunately, many of these problems have readily diagnosable, easy-to-cure causes. Unfortunately, if you rule out the simple fixes without finding one that's to blame, you may be left with a repair bill.

Cartridge Vs. Printer

Differentiating a defective cartridge from a machine malfunction enables you to separate simple fixes from more-complex repairs. If toner spots appear only in cyan, magenta, yellow or black on output from a color laser printer, replacing the toner cartridge for the affected shade may enable you to rule out a hardware problem immediately. If you're troubleshooting a monochrome laser printer, you're facing only one potentially defective toner cartridge -- black -- and the presence of spots in any other color signals a different problem altogether. Bear in mind that running color-copier or color-laser output through a monochrome laser printer to add a title, logo, caption or other information may cause the original printout's toner to unfuse inside your machine, contaminating the path your printouts take from input to output tray and causing spots.

Random Spots

If you've had to replace a defective cartridge that leaked toner inside your printer, installing a working replacement may not resolve your problem completely. Because laser toner consists of powdery, microscopic particles of plastic and coloring agents, it can sift into crevices and linger inside the machine, depositing blemishes on subsequent printouts. If your printer remains under warranty, you may be able to resolve the problem without paying for manufacturer service. If it's out of warranty, contact a technician who can give your machine a thorough cleaning.

Repetitive Spots or Streaks

Laser printer manufacturers maintain lists of repetitive defect information you can use to quantify the source of toner flaws that occur at regular intervals. Because the devices' internal hardware falls at specific positions relative to each page of their output, the location of the markings identifies the component that's causing the spots. If the manufacturer of your device doesn't provide repetitive-defect measurements for it, or only discloses this information to service technicians, you may be unable to diagnose these kinds of problems yourself.

Tiny Yellow Dots

The pattern of small yellow dots you see when you look closely at the output of a color laser printer serves as the equivalent of the machine's fingerprint, identifying it by make and model. Unlike the smudges, streaks, blobs and smears that signal cartridge or hardware problems, this micro pattern may be annoying, but it's a feature, not a bug. Hardware manufacturers implemented this system in conjunction with law-enforcement agencies to cut down on the reproduction of materials that can't be duplicated legally, such as currency.