CLS621 Overview

CLS621 Overview

Here’s our CLS621 Overview, we use these printers for our Prime Series because they provide a fast and lean answer to printed number plates. This page highlights the important parts and locations on the Citizen printer. Refer to this page when troubleshooting or to find out what a part is called or where it’s located.

Video Guide

Play ButtonCLS621 Printer Overview – YouTube

Front View

cls621 Overview - Front View of Printer

Front View of CLS621 Printer

The front view shows the printers main controls, output and top cover. This is where most interaction with the machine occurs.

  • A: Top Cover – Opens vertically to allow access to the inside.
  • B: Vent – Discharges built up heat.
  • C: Control Panel – Button settings and alerts.
  • D: Top Window – View the ribbon status.
  • E: Side Window – View the media status.
  • F: Output – Printed media output.

Rear View

CLS621 Overview - Rear View

Connect power & USB cable to the back of your CLS621

The rear view shows the printers mains switch and power points, along with the interface ports.

  • A: Power Switch – Toggles mains power on or off.
  • B: Power Socket – Mains power cord socket.
  • C: USB Port – Used to connect printer to a PC.

Control Panel

CLS621 Control Panel

The control panel and LED lights

The control panel is where the user interacts with the printer, with options to begin, pause and stop operation.

  • A: Power LED – Green when on.
  • B: Print LED – Green when ready.
  • C: Condition LED – Orange when active.
  • D: Error LED – Red for fault.
  • E: Pause Key – Pauses current print job.
  • F: Feed Key – Moves media to the start position.
  • G: Stop Key – Stops printing or cancels the alarm.
  • H: Mode/Repeat Key – Exits current mode in menu or reprints the last job.


CLS621 Inside view

The CLS621 print unit, sensor and release lever

Inside the top cover you’ll find the print unit and media set-up controls.

  • A: Print Unit – Ribbon & printing unit.
  • B: Sensor Arm – Detects media start position.
  • C: Winding Core – Collects the used ribbon.
  • D: Ribbon Core – Feeds the ribbon out when printing.
  • E: Release Lever – Unlocks the print unit.
  • F: Top Cover – Opens up to access interior.

Media Alignment Controls

CLS621 Media Alignment Controls

Close-up view of the media alignment area

These media controls help to position, align and pull the media through the printing unit.

  • A: Sensor – Detects media start position & perforations.
  • B: Media Guide – Helps align media for printing.
  • C: Sliding Media Guide – Adjusts to fit the media width.
  • D: Platen – Feeds and retracts media through the print unit.
  • E: Print Head – Uses heat to apply ink to the component.
  • F: Recess – Used for the internal roll feed.

Media Adjustment Controls

CLS621 Media Adjustment Controls

These controls adjust print width, pressure & ribbon tension

The adjustment controls are where you set the printing pressure, width and ribbon tension.

  • A: Front ribbon tension knob (winding) – Adjust to suit ribbon width and if ribbon is wrinkled or slips.
  • B: Front ribbon left-right balance knob (winding) – Set to centre position and adjust if ribbon is wrinkled.
  • C: Media width dial – Adjust to suit media width, set to 9 for standard oblong.
  • D: Back ribbon tension knob (feeding) – Adjust to suit ribbon width or when ribbon wrinkles or slips.
  • E: Back ribbon left-right balance knob (feeding) – Set to centre position and adjust if ribbon is wrinkled.
  • F: Media thickness dial – Adjust to suit media thickness, set to 4 for our reflective.
  • G: Print head lever – Push lever to raise print unit to install media & ribbons.

Sheet Fed

CLS621 Printer Overview - Sheet Feed

The rear tray is used for loading sheets into the printer

  • A: Media Tray – Holds reflective sheets before printing.
  • B: Raised Media Lip – Helps to align & feed media i nto the printer.
  • C: Reflective Sheet – Positioned correctly against the side of the tray and media lip.

Roll Fed

CLS621 Internal Roll Fed

Small rolls can be used inside the printer

  • A: Print Unit – Holds the ribbon & print head.
  • B: Sensor Arm – Detects perforation notches and start marks.
  • C: Media Roll – Perforated reflective panels on a roll.
  • D: Media Bar – Holds & helps feed media rolls.

External Roll Fed

CLS621 External Roll Fed

Larger rolls have to be mounted outside your printer

  • A: Roll Holder – Holds media rolls.
  • B: Media Roll – Perforated reflective panels on a roll.
  • C: Media Bar – Holds & helps feed the media roll.

Need Help?

This is a basic overview of the Citizen CLS621 Number Plate Printer. Please refer to your user or manufacturers guide for more up-to-date information. If you’ve an account, you can order replacement CLS621 Consumables from our online NP-Shop.

Our knowledge base contains articles with details on replacing this printers ribbon and using media sheets or rolls. Not to mention its required operating conditions and approved printer settings. And has solutions to common number plate print issues and printer errors.