My HP Laser Jet Pro M12a printer (black only) started printing horizontal streaks (around 4 per page).Tried shaking the toner, cleaning the roller and other parts, and running the cleaning page setup in the system but still doesn't get rid of the streaks. Toner is still 100% capacity based on supplies states print page. How do I get rid of these? Thanks
Repetitive horizontal lines are often caused by the drum unit or cartridge that matches the color. If you google repetitive defect chart for your model of printer it will give you a measurement ruler and the components that are causing the print defect based on that spacing.
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