“Half Cycle Test” troubleshoot defective toner and image defects like the pros.
The “half cycle test” is a great printer repair technique for determining if you have a defective toner or other image quality issues within your laser printer. A half cycle test is basically stopping a print job in various areas of the print cycle. Inspecting the print at different points of the print cycle helps to eliminate possible causes for the problem.
Before even attempting this test inspect the toner cartridge for obvious defects. Open the flap on the toner cartridge and inspect the drum surface. If the drum itself appears to be damaged the toner cartridge is probably bad.
How to Perform a “Half Cycle Test”:
From the control panel, print a test page using the manual tray. As you hear the print job make it’s way through the printer open the top cover to stop the printer. Remove the print job and examine the paper at different stages in printing (stop print job before the page goes into the fuser assembly). If it’s good before entering the fuser, the fuser is probably bad. If it’s bad on the paper but good on the drum, the issue is either the transfer roller or high voltage power supply. If it’s bad on the drum it is probably the toner cartridge but in a rare case could be the formatter or scanner assembly.
It may take several tries to get the print job to stop in the correct spot.
Opening the printer during the print cycle will cause a paper jam.
Remove the paper with care to not damage other components of the printer.
The toner will not be fused to the paper when you remove it, therefore this can get messy.