HP LaserJet 4250 Service Manual - Page 394
Check the print cartridge, EconoMode, TONER
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Check the print cartridge Image-formation defects are often the result of problems with the print cartridge. If you suspect that the print cartridge is the source of the problem, replace the print cartridge before troubleshooting image defects. Use the following list to make sure that the print cartridge is still operable. ■ Check the print cartridge to see if it has been disassembled or refilled. ■ Inspect the cartridge for toner leaking through worn seals. (If the drum has been manually rotated, it might have caused internal damage, and toner spills can result.) NOTE Print cartridges are rated for 10,000 (LaserJet 4250/4350), 12,000 (LaserJet 4200), 18,000 (LaserJet 4300), and 20,000 (LaserJet 4250/4350) images at 5% coverage. It is possible to wear out the photoconductive drum gears and the cartridge seals before TONER LOW appears on the control panel if average toner coverage is less than 5%. See EconoMode. ■ Check the surface of the photosensitive drum in the cartridge to see if it has been damaged or scratched. Touching the drum contaminates the photosensitive surface and can cause spotting and defects during printing. ■ Dark areas on the page might indicate that the drum has been exposed to light for too long. If dark areas appear, stop the printer and wait a few minutes This should eliminate most defective images. If not, placing the print cartridge in a dark environment for several days can restore some life to the drum. EconoMode EconoMode creates draft-quality printing by reducing the amount of toner on the printed page by up to 50%. Advise the customer to turn EconoMode on or off from the printer driver or software program, because those settings override the control-panel settings. EconoMode settings can also be changed from the print-quality menu on the control panel. CAUTION Hewlett-Packard does not recommend full-time use of EconoMode. If EconoMode is always used, the toner supply will probably outlast the mechanical parts in the print cartridge. 380 7 Troubleshooting