Zebra GK420 Label Printer: GK420d vs GK420t Buying Guide

The Zebra GK420 label printer is a 4 inch, 203 dpi desktop printer that Zebra built in two versions: the GK420d for direct thermal labels and the GK420t for thermal transfer with a ribbon. It became one of the most common printers on shipping benches, pharmacy counters and small warehouses, and many sites still run fleets of them today.

We list eighteen GK420 part numbers, nine GK420d and nine GK420t, all refurbished. This guide explains how to pick between the d and t versions, which interface build to order, what media and ribbon each one takes, how setup works with ZPL and EPL2, what Zebra says about end of support, and how the GK420 compares with the GX420, GC420 and ZD421 we also carry. For recorded values, jump to the GK420 specs table or the full GK420 range.

Products in our listing

Four GK420 builds are shown below, one per print method and interface; the full range table lists all eighteen part numbers.

ZebraGK42-202210-000Zebra GK420d 4-Inch 203dpi Direct Thermal USB/Ethernet Desktop Label PrinterIn stockView Details →

ZebraGK42-202510-000Zebra GK420d 4-Inch 203dpi Direct Thermal USB / Serial / Parallel Desktop Label PrinterIn stockView Details →

ZebraGK42-102210-000Zebra GK420t 4-Inch 203dpi Thermal Transfer USB/Ethernet Desktop Label PrinterIn stockView Details →

ZebraGK42-102510-000Zebra GK420t 4-Inch 203dpi Thermal Transfer USB / Serial / Parallel Desktop Label PrinterIn stockView Details →

Every GK420 we list is refurbished and carries the 30-Day Tech Seller USA warranty. Browse the full Zebra printer range or all printers and scanners.

Zebra GK420d specs and GK420t specs

Values below come from our product data for the GK420d and GK420t part numbers we list. The two versions share most of their recorded specs; the differences are print method and weight.

What the Zebra GK420 label printer is for

The Zebra GK420 label printer is a general purpose 4 inch desktop model. At 203 dpi and up to 5 inches per second, it prints the labels most businesses need every day: 4 x 6 shipping labels from carrier and marketplace platforms, carton and pallet labels, receiving and putaway labels, product and shelf labels, and pharmacy and prescription labels. Our shipping label compliance guide explains what carriers expect on a 4 x 6 label.

It is a good match for single stations that print a steady stream of labels through the day, and for multi-unit sites that want the same printer at every packing bench, counter or workstation. Because every GK420 we list is recorded with the same width, resolution, speed and command languages, label formats move between d and t units without redesign. For very high daily volumes or wide labels, an industrial printer is the better tool; our industrial vs desktop label printers guide explains where that line falls.

The GK420 sits in the middle of the Zebra G-Series. Our Zebra G-Series GC vs GK vs GX guide compares the whole range at a glance; this guide goes deeper on the GK420 itself, part number by part number.

GK420d vs GK420t: choosing the print method

The GK420d prints direct thermal only. It needs no ribbon: heat from the printhead darkens coated label stock directly. That keeps running costs and operator steps low, which is why the GK420d is the usual choice for shipping labels, receipts and other labels that only need to last weeks or months. Direct thermal labels fade with heat, sunlight and time, so they are not meant for long-term asset or product identification.

The GK420t is recorded in our data as thermal transfer and direct thermal. It accepts a ribbon for durable labels on paper or synthetic stock, and it can also run direct thermal labels with no ribbon loaded. Choose the GK420t when the same station prints both short-life shipping labels and long-life product, asset or compliance labels. Our direct thermal vs thermal transfer guide explains which labels need a ribbon.

The weights in our data reflect the difference: 3 lbs for the GK420d and 4.6 lbs for the GK420t, which carries the ribbon mechanism. If you are replacing a printer, check the part number on its label: GK42-1 part numbers are GK420t units and GK42-2 part numbers are GK420d units in our listing, and the GK4H prefix marks the two units titled as Healthcare versions. Our guide to specifying Zebra healthcare label printers covers how those are chosen.

Ethernet or parallel: picking the interface build

Each GK420 part number in our listing is recorded with one of two interface sets. Ten are USB with Ethernet, which suits shared printing from a warehouse system, ERP, pharmacy system or shipping platform over the network. Six are USB with serial and parallel, which suits a single workstation or older equipment that still talks over a serial or parallel port. Two GK420t part numbers, GK42-100110-000 and GK42-100111-000, do not have a usable interface value in our data, so confirm the ports on those units with us before ordering.

When you replace an existing unit, read the full part number from the label underneath the printer and match it, rather than ordering by model name alone. Matching the part number keeps the interface, the driver configuration and the operator routine the same. When you add new stations, choose Ethernet if the printer will be shared or managed centrally, and USB if one computer drives one printer. Our printer connectivity guide covers each option in detail.

Labels, media and GK420t ribbon

Our data records a media width of 0.75 to 4.25 inches and a maximum print width of 4.09 inches (104 mm) for every GK420. That covers small 1 inch product labels up to standard 4 x 6 shipping labels, on rolls or fanfold stock.

For the GK420d, buy direct thermal labels only; thermal transfer paper will not image without a ribbon. For the GK420t ribbon, match the ribbon width to the label, or a little wider, and match the ribbon type to the face stock: wax for paper labels, wax and resin for coated paper and many synthetics, and resin for polyester and polypropylene labels that face chemicals, heat or abrasion. Use ribbons made for Zebra desktop printers so the core and winding direction fit. Our label media and ribbon selection guide goes into detail on matching media to the job.

GK420 driver, ZPL and EPL2 setup

Our data records ZPL II and EPL2 for every GK420. ZPL II is the language most modern label software, shipping platforms and warehouse systems send to Zebra printers. EPL2 is the older Zebra desktop language used by the LP and TLP 2844 generation, and support for it lets a site still sending EPL from older software swap in a GK420 without rewriting label formats. Our ZPL vs ESC/POS command languages guide explains the differences, and our guide to legacy Zebra LP and TLP printers covers the models many GK420 units replaced.

Zebra lists Zebra Setup Utilities and its Windows printer driver on the GK420d support page, and the Zebra GK420d user guide recommends installing the driver before you connect the printer to the computer. A practical sequence: install the GK420 driver, load media and, on a GK420t, the ribbon, run a media calibration, print a configuration label, set the network address on Ethernet builds, then print your real labels from your own application.

The recorded memory is 4MB Flash and 8MB SDRAM. That is plenty when your software sends a complete label each time, but limited if you store many formats, fonts or graphics on the printer. If labels print in the wrong place or skip, recalibrate first; our label printer troubleshooting guide walks through the common faults.

GK420 end of support and the GK420d replacement ZD421

Zebra lists both versions as discontinued. On the GK420d support page, Zebra gives a printer discontinuation date of January 31, 2022 and a service and support discontinuation date of April 30, 2025 for North America, EMEA and Latin America, and names the ZD421 as the replacement. The GK420t support page gives the same discontinuation dates; it does not name a replacement model on the page we checked (checked November 2026).

What this means for buyers: Zebra no longer sells new GK420 printers or offers support for them, so refurbished units are the practical way to keep an existing GK420 fleet consistent with the same templates, media and drivers. For a new deployment or a multi-year plan, the ZD421 is the model Zebra points to for the GK420d. Our Zebra ZD421 desktop label printer guide and Zebra ZD Series desktop printers guide explain the newer range.

Buying a refurbished GK420: what to check

Printhead. Print a test pattern or configuration label on arrival and look for white lines through text or barcodes, which point to failed dots. Our printhead failure diagnosis and replacement guide explains what to look for.

Platen roller. A worn, glazed or sticky platen causes skew, slipping and light print that is often mistaken for a head fault. Our thermal printer maintenance guide covers cleaning intervals.

Interface and accessories. Confirm the build matches your part number, that the Ethernet or parallel port you need works, and that the power supply and cord are included.

Ribbon path on a GK420t. Load a ribbon and print a few labels to confirm even, wrinkle free output before the unit goes into service.

Condition terms. Our refurbished hardware grading guide explains what refurbished means at Tech Seller USA.

GK420 vs GX420, GC420 and ZD421 in our listing

The Zebra GX420d (GX42-202411-000) is the step up in the same G-Series family. Our data records it at 203 dpi direct thermal, up to 6 in/sec (152 mm/s), the same 4.09 inch print width and 0.75 to 4.25 inch media width, 4MB Flash and 8MB SDRAM, ZPL II and EPL2, USB, serial and Ethernet, and 3 lbs. Choose the GX420d when a station needs a little more speed or a serial port alongside Ethernet.

The Zebra GC420d (GC420-200510-000) is the entry G-Series model. Our data records it at 203 dpi direct thermal, a 4 inch print width, ZPL and ZPL II, USB, serial and parallel, and 3 lbs, with no print speed recorded. It suits a single workstation where cost matters more than network printing.

The ZD421 is the replacement Zebra names for the GK420d. Our Zebra ZD421d (ZD4AH42-D01E00EZ) is recorded as refurbished, 203 dpi direct thermal, up to 6 in/sec (152 mm/s), 4 inch print width, 512MB Flash and 256MB SDRAM, ZPL II and EPL2, USB and Ethernet. For ribbon printing, the Zebra ZD421t (ZD4A042-30EM00EZ) is recorded as 203 dpi thermal transfer, up to 6 in/sec, with the same memory and languages. Both keep EPL2 and ZPL II, so GK420 label formats usually carry over.

Full GK420 range in our listing

Every GK420 part number we list is below. All are 203 dpi and refurbished. Select a part number to open its product page.

Common questions