The Encoder Strip located on the back of the carriage should be cleaned on as needed if becomes covered in ink mist or if ink has landed on the strip.
In order to clean the encoder strip, you will need to first release the print carriage. From the Maintenance menu select the Motion tab and then select Release Carriage. If cleaning the inside of the encoder board is needed to remove any lint, gently remove the encoder strip from the encoder board and thread a lint free wipe through the sensor.
Cleaning with a lint free wipe and 91% isopropyl alcohol will help remove any ink mist that has gotten on the sensor. Dry the encoder board, then place the encoder strip back in the encoder board sensor slot.
If the encoder strip was not put back in the sensor, an Encoder Failure error will be displayed.