Cleaning the Sensor – Upper Half of the ZD421 Ribbon Cartridge Printers

Pull the two release arms out to release the ribbon drive transport. For instructions on how to access the printhead, see Accessing the Printhead of the ZD421 Ribbon Cartridge Printer.

Swing the printhead actuator arm up until it touches the printer’s top cover. Hold the actuator arm in this position for access to the area below the printhead.

Spray the upper web (gap) array sensor under the ribbon drive transport and the ribbon-out sensor on the underside of the printhead actuator arm with a can of compressed air. If necessary, use an alcohol-moistened swab to break up any accumulated debris.

Use a dry swab to remove any residue that may be left from the first cleaning.

If the cartridges are not being detected, you may need to clean the ribbon cartridge sensor interface pins. Clean the pins using a clean swab or lint-free cloth lightly moistened with 99.7% pure isopropyl alcohol, using a gentle wiping motion from right to left.