HP Laser Printer Common LCD Service Error Codes.
HP Maintenance Resets
Laser printer manufacturers often build a maintenance interval into the machine's firmware just as car manufacturers do. If you want reliable trouble free printing then it is sensible to take some note when the printer prompts for maintenance, give the machine a clean and change the parts indicated.
In the past cleaning a printer needed some specialist equipment like a "Convac". Toner particles can be just a couple of microns across so they would pass through the filter of an ordinary vacuum cleaner and at least make the room dirty. (Manufacturers generally say that toner is not a health hazard).
Replacing rollers and the fuser also needed both some technical skill and patience. The printer would need to be be stripped of its covers and removing some rollers meant taking of "E-rings" and circlips. Some of the low cost printers are still like this.
Manufacturers therefore had reason to try and reserve maintenance to service engineers who knew a special procedure or code. They often still do this.
Maintainability has become more of an issue for a lot of people. IT skills are more widespread and many people just want to fix their own (or their businesses) printers.
Recent Monochrome PrintersPower off the printer. With the power off hold the left side of both the Item and Value keys whilst turning the power back on. Hold the keys until the display reads "Reset Maintenance Count" (Some models just say "Count") now release the keys.