Both the Service Code 21100 and 21000 are related to the horizontal encoder and are due to one of the following:

  • The encoder is dirty and needs cleaning.
  • The encoder is damaged or loose.
  • The encoder is not correctly placed in the sensor.
  • The encoder is missing.

In the vast majority of cases, the error appears because it is dirty or, if the error is appearing after cleaning it, it is no longer sitting between the sensor under the carriage unit.

The horizontal encoder is a thin semi-transparent strip that runs across the width of the printer, just in front of the metal carriage rail and helps the print head determine its position in the printer.

We recommend powering the printer off and cleaning it on both sides and along its entire width with some denatured alcohol or IPA and lint free cloth. Below is a photo of its location. You may need to perform this a couple of times to ensure it is completely clean and no residue remains on the strip. You may power the printer back on 10 minutes after cleaning it.


Should the error still persist despite performing or if you discover that the encoder is damaged or missing, please submit a ticket with our support team for further assistance.