The Zebra GK420d is a label printer that print DIRECT THERMAL labels only.  Max print width 104mm, Max label roll width (label plus backing paper) 108mm. Max roll outside diameter 127mm on a 12.7mm, 25mm or 38mm core.

The Zebra GK420d is a label printer that print DIRECT THERMAL labels only.  Max print width 104mm, Max label roll width (label plus backing paper) 108mm. Max roll outside diameter 127mm on a 12.7mm, 25mm or 38mm core.

How do I calibrate my Zebra GK420d Label Printer?

The quickest and easiest way to calibrate your Zebra GK420D label printer is to hold the green FEED button down. First the light on the button will flash once, then it will do a double flash. Let go of the button after the double flash, and the printer will start to feed labels forward slowly. This is the calibration process and only takes a few seconds.

If you are using Zebra Designer to print your labels, then you may find it easier to get the label design on the screen. Then go to FILE and PRINTER SETTINGS then under the ADVANCED SETUP tab, simply press the CALIBRATE button in the bottom right corner of the screen.

If neither of the above works after a couple of attempts, then make sure you have the correct label size in the settings of your label design software and you are using the correct gap sensor. Labels on a backing paper with a gap between them and no black line printed on the reverse of the backing paper should use WEB SENSING or LABEL WITH GAPS sensor, and if you use continuous labels or card stock or labels with gaps that also have a black line printed on the reverse of the backing paper, then you should select the MARK SENSING or LABEL WITH MARKS sensor.

If you still cannot get your printer to calibrate, then you will need to print a profile of the label sensor settings. To do this, simply hold the green feed button. The light on the button will flash once, then do a double flash, then three flashes. Keep the button held until it flashes seven times, then take your finger off of the button. This will then print a graph that looks like the one below:

The graph should show a 'spike’ where it picks up the label gap. If the graph shows no spikes, then the label gap sensor is either dirty or faulty.

General features

• Print technology: Direct thermal printing (no ribbons required).
• Speed: Prints up to 5 inches (127 mm) per second.
• Design: Compact, with a dual-wall reinforced plastic construction.
• Media loading: Features an OpenACCESS™ design for easy media loading.
• Processor: 32-bit RISC processor.

Printer specifications

• Resolution: 203 dpi (8 dots/mm).
• Print width: Up to 4.09 inches (104 mm).
• Print length: Up to 39 inches (991 mm).
• Memory: Standard 8 MB SDRAM (3 MB available to user) and 4 MB Flash (1.5 MB available to user).
• Media sensors: Reflective and transmissive sensors.

Media characteristics

• Maximum roll diameter: 5 inches (127 mm).
• Core diameter: 0.5 inches (12.7 mm), 1.0 inches (25.4 mm), and 1.5 inches (37.1 mm).
• Width: Can use labels from 0.75 inches (19 mm) up to 4.25 inches (108 mm) wide.
• Types: Supports a variety of media, including roll-fed or fan-fed, die-cut or continuous labels, tag stock, and wristbands.

Connectivity and software

• Standard connectivity: USB, serial (RS-232), and parallel interfaces.
• Optional connectivity: 10/100 internal Ethernet is available on some models.
• Programming languages: Comes standard with both EPL and ZPL printer programming languages.
• Software: Includes drivers for Windows and ZebraDesigner label design software. 

Zebra GK420d Label Printer

The Zebra GK420d is a compact and reliable direct thermal label printer ideal for retail, healthcare, and logistics environments.
Designed for simplicity and performance, it delivers consistent, high-quality labels without the need for ribbons.

Key Features

• Printing Technology: Direct Thermal (no ribbon required)
• Maximum Print Width: 104 mm
• Maximum Label Roll Width: 108 mm (including backing paper)
• Maximum Roll Diameter: 127 mm
• Core Sizes Supported: 12.7 mm, 25 mm, or 38 mm

Why Choose the GK420d?

1. This printer is ideal for shipping labels, barcode stickers, and product identification.
2. Its user-friendly design ensures quick media loading, minimal maintenance, and long-term reliability — making it a cost-effective choice for fast-paced workplaces.

 
Learn More

Visit the official Zebra page for full specs, drivers, and support:
???? https://www.zebra.com/gk420d