2021-01-10 repair hp5m laser printer

During the current corona lock-down a working printer is of profound use, when printing out task sheets for school assignments. Since some time the sheet feeder was working a bit erratic. From time to time the printer displays a paper jam error and stops working.

And then suddenly nothing worked any more. The paper was fed only some millimeters out of the paper tray, and then also a paper jam was reported.

So I disassembled the paper feed unit using the hp combined service manual.

hp5m
paper feed unit

The axle, which starts the paper feed process was a bit stuck and the time for feeding the paper to the first photocell contact was simply too long.

"Input Paper Delay Jam: When paper does not reach the Input Paper Sensor (PS1) within the required time." (see Functional Overview 5-11)

hp5m
setting of the paper-feed-axle gear before starting the feed process
hp5m
the paper-feed-gear is released by a solenoid actuator and then takes too long to reach the upper gear

Here simply greasing the axle was sufficient. Now the spring on the gear is strong enough to turn the axle in the required time. The printer is now working again.