Replacing the ZD421C Printhead
Replacing the ZD421C Printhead

Replacing the ZD421C Printhead

This procedure guides you through replacing the printhead.
Read this procedure first before you begin your repair.
  • Turn the printer OFF.
  • Open the printer.  Release the ribbon drive transport to access the printhead (1) by releasing the link arms. See Accessing the Printhead of the ZD421C Ribbon Cartridge Printer for more details.
The printhead becomes hot while printing. To protect from damaging the printhead and risk of personal injury, avoid touching the printhead. Only use the cleaning pen to perform printhead maintenance.
The discharge of electrostatic energy that accumulates on the surface of the human body or other surfaces can damage or destroy the printhead and other electronic components used in this device. You must observe static-safe procedures when working with the printhead or the electronic components under the top cover.
Shows the printhead with its ESD  and Hot Surface warnings
  1. Swing the printhead actuator arm up until it touches the printer’s top cover. Hold the printhead actuator arm in this position for access to the printhead. Push the printhead release latch toward the printhead (shown as pink for visibility). The right side printhead releases down and away from the printhead actuator arm.
    Shows the printhead release latch.
  2. Swing the loose right side of the printhead out of the printer. Pull it to the right a little to get the left side of the printhead clear. Pull the printhead down and free of the printhead actuator arm to gain access to its attached cables.
    Shows the printhead release and swinging out of the bracket.
  3. Gently but firmly pull the two printhead cable bundle connectors off of the printhead.
    Shows the printhead connector locations to disconnect the printhead.
  4. Align the printhead up to the printer. Push the right-side printhead cable connector into the printhead. The connector is keyed to only insert one way.
  5. Push the left side printhead cable connector onto the printhead.
    Shows the connectors plugged into the printhead.
  6. Insert the center tab on the printhead assembly into the center slot on the printhead actuator arm.
    Shows the
  7. Insert the left side tab of the printhead assembly into the recessed slot on the left side of the printhead actuator arm.
    Shows the printhead and bracket with tab and slot alignment..
  8. Push the right side of the printhead into the printer until the latch locks the right side of the printhead into the printer.
    Shows the right side of the printhead tab and slot alignment.
  9. Verify that the printhead moves freely into the printer when pressure is applied (see arrow) and remains locked when pressure is released.
    Shows pushing the printhead to verify the printhead is latched correctly.
  1. Clean the printhead. Use a new pen to wipe body oils (fingerprints) and debris off the printhead. Clean from the center of the printhead to the outside. See Cleaning the ZD421C Printhead.
  2. Plugin the printer power is disconnected.
  3. Load full-width label or receipt paper roll. Printing with a full-width roll verifies all elements of the printhead function.
  4. Print a Configuration Report. See Print a Configuration Report to Test Printing