Hello. My name is XXXXX XXXXX X will be assisting you today.
The error code 5100 usually comes up after paper jam on printers.The error indicates 2 possibilities, either their is something stuck or a sensor detecting the paper jam issues has faulted.
Please try the below stepsfirst of all please turn off the unit....unplug the power cable now remove the cartridge...manually slide the carriage assembly\ printhead back and forth also clean the rail against which the assembly slides with a tissue ensuring that there is no ink residue on it clean the golden contacts of the cartridges and the printhead with a cotton swab dipped in little alcohol. Now check the paper feed tray, roller assembly area and the area where the carriage moved for any stuck obstruction like paper, paper clips, pins etc and if found remove it.once done turn the unit back on and check
if even after performing the above steps, the error 5100 continues, then an electric sensor that detects paper jams has faulted. If the uniyt is within warranty cover get the unit serviced through CanonIf the unit is out of warranty, then you may contact a local repair store for service.However, sensors repairs\replacement in such case is costly and it is more cost effective to opt in for a new unit.let me know if you have any further queries