Always show the PROCESS ERROR - BELT CLEAR BY COVER,

replace the transfer belt try this site for parts as a start

Precision Roller Printer Toner Cartridges Parts and Supplies Office...

did you replace a transfer belt recently?

Hello the problem on my printer is
Process error belt clear by cover

I think this is mechanical problem and you need to check and remove belt-related assembly part.
Thanks

I told you. That is belt-assembly problem.

procces error-belt clear by cover

epson cx 16
PROCESS ERROR-BELT CLEAR BY COVER

KONICA MINOLTA 1690MF ERROR:
process error - belt (clear by cover)

SOLUTION: Open and close the scanner unit. Reseat the Image Unit and cycle the power to the machine. If the error persists and the machine is covered by warranty, a printer exchange is recommended.

KONICA MINOLTA SUPPORT PAGE:
https://kb.mykonicaminolta.com/selfservice_bus_anon/microsites/search.do?cmd=displayKC&docType=kc&externalId=TAD-doctad227704html0&sliceId=&docTypeID=DT_TAD_1_1&dialogID=10562139&stateId=1%200%2010556672

This is a scanner error. You could try the following...
Power off and remove the power supply(Power Cord) from the back of the unit.
Open the scanner cover. Check the scanner glass for cracks and the scanner casing for cracks. Close the scanner lid.
Open the top cover
Using the carrier belt, move the cartridge carrier to the middle of the unit.
Remove both cartridges, close the top cover, reinsert the power supply, and power on.
IF THE ERROR MESSAGE DID NOT COME BACK....
Power off and remove the power supply from the back of the unit.
Open the top cover
Using the carrier belt, move the cartridge carrier to the middle of the unit.
INSERT THE COLOR CARTRIDGE ONLY,
Close the top cover, reinsert the power supply, and power on
IF THE ERROR MESSAGE RETURNS.. GET A DIFFERENT COLOR CARTRIDGE AND REPEAT THIS PROCESS....
IF THE ERROR MESSAGE IS GONE,
Power down as before, do all the same to get the carrier to the middle of the unit and RE-INSTALL THE BLACK CARTRIDGE.
Power back up as in previous steps...
NO ERROR? SHOULD BE GOOD TO GO..
ERROR?? TRY DIFFERENT BLACK
If after trying all of the above and the error message does not go away, you unit would need serviced (if it's under warranty, it's worth it; if not, you might want to replace it.)

This printer is same as Samsung CLP-500. So the problem is the same: Contaminated transfer belt sensor.

Do as follow:
Lift transfer belt assy from printer(Drop down back door 90 degree, press white button, lift top cover and release 2 locking levers, grab handle, pull the belt unit out), turn upside down & rotate plastic roller until small clear "window" appears along one edge of belt. Clean both sides of clear window with cotton bud. on same side as window, remove 2 screws securing flimsy plastic cover to gain acess to sensor, (follow red/black wires)remove a screw and pull out "U" shaped sensor(light transmiter and receiver), cotton bud and blow away dust on slits on inner surfaces of sensor. Reassamble and everything should be ok.If not, senser may be too contaminated, clean slits vigorousley with cotton bud, or maybe you just need a new sensor.

The theory is that printer detect transfer belt by transmit light through the clear "window". If either window not clear or sensor is contaminated, light will not reach the receriver part of the sensor, printer will report such errors.

Good luck.