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Troubleshooting Laser Printer Parts and Techniques With The Halfway Test Or Stop Test

Updated: Apr 14, 2019

Troubleshooting Laser Printer Parts and Techniques

Most types of printer errors and problems have multiple possible causes, so it’s not always eas to determine which part you need to fix a given problem. Some troubleshooting is often necessary to narrow down the possibilities.

One of the most useful troubleshooting techniques is the “halfway test,” also called the “stop test.” It is useful whenever you have an image defect or a paper skewing or wrinkling problem, because it allows you to determine where in the paper path the problem is originating.

Other Helpful Resources

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How it works

Send a print job or print a configuration page, then stop the page partway through the printer by opening the lid. For image problems, the ideal time to stop the paper is when about half of it is past the toner cartridge.

Remember that the toner is unfused at this point, so be careful not to make a mess! Presumably, you already know what the image defect looks like on a completed print. This test allows you to view the image in two earlier stages: on the paper before it goes through the fuser, and on the drum inside the toner cartridge, before it gets transferred to the paper.

Troubleshooting Laser Printer Parts and Techniques With The Halfway Test Or Stop Test

If the image looks good in both of these places but bad on the finished print, it’s a pretty good bet that the fuser is causing the problem. If it’s bad on the paper before fusing but looks good on the drum, then the problem is originating in the transfer stage—bad transfer roller or high voltage to the transfer roller.

If it’s already bad on the drum, you can eliminate the fuser and transfer roller and conclude that the defect is originating at an earlier stage in the print process—perhaps a bad formatter board, laser/scanner unit, or the toner cartridge itself.

For skewing or wrinkling problems, you may want to stop the paper at various different points in the paper path to try and isolate where it first skews or wrinkles.

For example, if the paper is straight whenever you stop it before the registration rollers, but skewed whenever you stop it after that, the registration assembly is a top suspect.

If paper is wrinkling in the fuser, but is already skewed before that, there’s probably nothing wrong with the fuser—the paper is wrinkling because it’s feeding crooked, so the fault is earlier in the paper path.

It takes some practice to be able to stop the paper in the desired spot—one way to make it easier is to feed from the manual tray. This allows you to watch the paper as it moves into the printer, and it will be easier to judge its position.

This is especially important on color printers with more complex print cycles, because paper movement is often delayed while the image is developed in several stages, and it’s hard to tell where the paper is at any given time if you can’t see it.

The halfway test is only one of many troubleshooting techniques—we will cover more in the future—but it’s one of the most useful, since image defects and paper feed problems are among the most common things that go wrong in printers.

Metrofuser is a leading global innovator, manufacturer of printer parts, equipment, diagnostics, repair information and systems solutions for professional users performing critical tasks. Products and services include hp printer parts, printers and printer repair training. Parts include hp printer parts such as printer fusers, printer maintenance kits and other hp printer replacement parts. The company's, customers include office equipment dealerships, online retailers, repair centers and MPS service providers nationwide. Metrofuser has been named to Inc. Magazine’s fastest growing companies five consecutive years.