Zebra GX420 troubleshooting guide: errors, faults and fixes

Short answer: The ribbon has run out: according to the GX420t guide, the light turns red and the printer waits for a new roll. Leave it switched on, replace the ribbon, close the cover and press FEED to resume printing.

Likely cause

Zebra Uni-Ribbon ribbons have a reflective leader at the end of the roll that stops printing when the ribbon is empty. The Zebra set-up article for the GX Series specifies that if the sensor does not see this leader, the printer keeps trying to print.

Caution: Zebra requires approved ribbons: an unapproved ribbon can damage the printhead.

What to do

1. Leave the printer switched on: switching it off while reloading causes the current data to be lost.
2. Open the cover and cut the used ribbon.
3. Load a new roll and an empty core with square notches (see loading the ribbon).
4. Close the cover and press FEED to restart printing.

If the printer does not stop at the end of the ribbon, check that it is a Zebra ribbon fitted with its end leader (reflector).

Sources: Replacing Supplies (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) · Replacing consumables (opens in a new window) – Guide d'utilisation Zebra GX420t / GX430t, imprimante thermique de bureau (French user guide; PDF, 980612-021 Rev. C) · Loading Transfer Ribbon (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) (official documentation).

Short answer: The printer is paused. Press FEED once: it switches to ready mode (light solid green) and resumes printing.

Likely cause

According to Zebra, the printer pauses following an error or a programming command. The GX guide also states that it can initialise in pause mode, with the light flashing green.

What to do

1. Press FEED once.
2. Check that the light changes to solid green: the printer is ready.
3. If the data sent still does not print, see flashing green light.

Sources: The LED on Printer Is Flashing Green but the Printer Is Not Printing – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Status Light Error Resolutions (opens in a new window) · Printing a Test (Printer Configuration) Label (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Operator Controls (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: With the printer switched on and the cover closed, hold down FEED and release it during the sequence of two green flashes. The GX420 detects the media type and length, adjusts its sensors and feeds one to four labels.

Likely cause

According to the Zebra set-up article for the GX Series, the two-flash calibration finds the gap between labels and measures their length; it should be done on first loading and every time the label length changes. The media tracking mode (gap, black mark, continuous) must also match the loaded media.

Official calibration procedure (two flashes)

1. Load the media and close the cover.
2. Switch on the printer; if the light is flashing green (pause), press FEED once.
3. With the light solid green, hold down FEED: the green light flashes once, then in sequences of two flashes.
4. Release it during the sequence of two flashes: the printer starts the standard automatic calibration (equivalent to the ZPL command ~JC).
5. It feeds one to four labels, then returns to the ready state.
6. If the labels do not calibrate correctly, perform a manual calibration (seven flashes).

The GX guide also states that after power-up, with the light solid green, pressing FEED two or three times makes the printer calibrate to the installed media; it may then feed several labels.

Sources: Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · Printing a Test (Printer Configuration) Label (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: With media loaded and the printer switched on, hold down FEED until the sequence of seven green flashes, then release it. The GX420 adjusts its sensor, prints a sensor profile and saves the settings; then press FEED: one whole blank label should come out.

Likely cause

Zebra recommends manual calibration with pre-printed media or when the printer does not calibrate correctly. The Zebra GX Series article advises it if the labels do not calibrate with the two-flash sequence: it analyses the gap or mark more precisely and creates a sensor profile.

Official manual calibration procedure (seven flashes)

1. Load the media.
2. Switch the printer on.
3. Hold down FEED: the green light flashes in sequences; release it during the sequence of seven flashes.
4. The printer adjusts the sensor to the liner, feeds the roll until a label is positioned under the printhead, prints a sensor profile and saves the settings.
5. Press FEED: one whole blank label should feed.
6. If not, restore the factory defaults (four flashes, see reset) then recalibrate.

According to Zebra, manual calibration disables automatic calibration; the four-flash reset restores it. Command equivalent: ~JG in ZPL.

Sources: Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) (official documentation).

Short answer: If the GX420 finds no label, black mark or notch within 1 metre (39 inches), it switches to continuous media mode. Check that the tracking mode matches the media and that the gap or mark passes over the sensor, then perform a manual calibration.

Likely cause

Zebra explains that the printer continuously adjusts its measurement of label length and switches to continuous (receipt) mode if nothing is detected within the default maximum length, until this is changed by software, programming or manual calibration. The reflective and transmissive sensors are slightly off-centre in the paper path: the gap, hole or black mark must pass in front of them.

What to do

1. Check the media tracking mode in the driver: gap detection (web sensing, default setting), black mark (mark sensing) or continuous.
2. Check that the gap, hole or black mark passes correctly over the sensor; with the movable sensor option, adjust its position (see movable sensor).
3. Clean the sensors (black line, gap, label taken), on which dust accumulates: brush them gently, if necessary with a dry cotton swab; remove adhesive with a cotton swab moistened with alcohol, then go over them again with a dry cotton swab until no residue or marks remain.
4. Run a manual calibration (seven flashes).

For programmers: the maximum label length (^ML) must be at least twice the longest label; ^MN sets the tracking type and ^MNA restores automatic detection. Zebra advises against changing these settings if you alternate between media of different lengths or detection types.

Sources: Media Sensing (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 · Sensor Cleaning – User Guide Zebra GX420d Desktop Thermal Printer (980611-001 Rev. B, 2008) (official documentation).

Short answer: For black marks or notches, align the sensor arrow with the right-hand edge of the mark; for gap labels, leave it in the default gap detection zone. Outside this zone, Zebra states that it does not reliably detect either gaps or continuous media.

Likely cause

The movable sensor detects black marks or notches on the back of the media, even off-centre. It only reliably detects continuous media and gaps between labels in the default gap detection zone.

What to do

1. For black marks or notches: turn the media over on the roll to reveal the marks on the back.
2. Slide the sensor from its central position until its arrow is aligned with the right-hand edge of the mark (mark on the left or in the centre of the media), or centre the sensor cover under an oval notch or a mark located on the right.
3. Position the sensor as far as possible from the edge of the media, which can shift sideways.
4. For gap labels: put the sensor back in the gap detection zone, with the arrow pointing at the alignment key; the default position is off-centre so as to also detect gaps between labels placed side by side.

With the cutter option, the default sensor position is slightly to the right of centre.

Sources: Moveable Blackline Sensor Option (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Moveable Blackline Sensor Option (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) (official documentation).

Short answer: This is the default setting: according to Zebra, the GX420 feeds a label at power-up and when the printhead is closed, to put a calibrated label in position. This behaviour can be changed with the ZPL command ^MF.

Likely cause

Media Feed action set by default to feeding one label. The other possible settings are calibration, feed, length, no motion and short calibration.

What to do

1. If this behaviour suits you, no action is needed.
2. To change it, send the ^MF command to the printer, for example with the send file function in the ZDesigner driver tools.
3. If you keep this setting, repeat the two-flash calibration every time the label length changes (see calibration).

According to the Zebra article, the printer only measures the label length at power-up or when the printhead is closed if these actions are set to Length or Calibrate.

Sources: GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · Media Sensing (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: Leave the printer switched on while reloading: switching it off would cause the data to be lost. Load a new roll, close the cover and press FEED to restart printing.

Likely cause

Media run out during a print job. The pages of the GX guide consulted do not specify the light state in this case.

What to do

1. Keep the printer powered on.
2. Open the cover and install a new roll (see loading labels).
3. Close the cover until it clicks.
4. Press FEED to restart printing.

Zebra recommends approved, good-quality labels: labels that do not lie flat on their backing can catch on the guides and rollers and cause jams.

Sources: Replacing Supplies (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Replacing Supplies (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) (official documentation).

Short answer: Open the cover, pull the guides apart and place the roll on its holders, print side up. Bring the paper out at the front, under both guides, then close the cover until it clicks; if the movable sensor is installed, it must be in its default position.

Likely cause

Zebra stresses the orientation of the roll (print side up as it passes over the platen roller), a roll that turns freely without resting on the bottom of the compartment and, with the movable sensor option, its position: off-centre, it only detects black lines, black marks and notches.

Caution: Electrostatic discharge can damage the printhead and the electronics: Zebra asks you to follow anti-static precautions when working under the cover.

What to do

1. Open the printer by pulling the release latches towards you and lift the cover.
2. Pull the media guides apart, place the roll on the holders and release the guides; the print side must face up as it passes over the platen roller.
3. With the movable black line sensor option, check that it is in the default central position.
4. Pull the paper so that it sticks out at the front; check that the roll turns freely and does not rest on the bottom of the compartment.
5. Thread the paper under both guides.
6. Close the cover, pressing down until it snaps into place.

With the cutter option, the sensor's default position is slightly to the right of centre and the paper passes through the inner slot of the cutter (see cutter).

Sources: Placing the Roll in the Media Compartment (opens in a new window) · Loading Media with the Cutter Option (opens in a new window) · Your Printer (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: Place the new roll on the lower supply spindles and an empty core on the take-up spindles, attach the leader to the empty core, tension the ribbon with the thumbwheel, then close the cover and feed at least 10 cm of media with FEED. Then switch the printer to thermal transfer mode.

Likely cause

The GX420t requires Zebra Uni-Ribbon ribbons, fitted with an end leader (reflector). According to Zebra, the ribbon must be wider than the media, coated on its outer side, and mounted on cores with square notches.

Caution: Never use a ribbon with direct thermal media. Do not use the old cores with notches on one side only, or cores with rounded, frayed or crushed notches: according to Zebra, a core that is not properly locked can slip and crease the ribbon.

What to do

1. Remove the packaging from the ribbon and peel off its adhesive strip.
2. Open the printer and place the new roll on the lower supply spindles, with the notches locked onto the left hub.
3. Place an empty core on the take-up spindles: the first one is supplied with the printer; after that, reuse the empty core from the previous roll.
4. Attach the ribbon leader to the empty core with its adhesive strip, centring it.
5. Turn the left thumbwheel backwards until the ribbon is taut over the printhead.
6. Close the cover and press FEED to feed at least 10 cm (4 inches) of media: slack and creases in the ribbon disappear.
7. Change the print mode from direct thermal to thermal transfer (driver, software, ZPL command ^MT or EPL command O), then print a configuration label: PRINT METHOD must show THERMAL-TRANS.

Sources: Loading Transfer Ribbon (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) · Loading the transfer ribbon (opens in a new window) – Guide d'utilisation Zebra GX420t / GX430t, imprimante thermique de bureau (French user guide; PDF, 980612-021 Rev. C) · Ribbon Overview (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) (official documentation).

Short answer: Zebra cites a core that is not properly locked and slips, media drifting sideways or a printhead that is not properly latched. Check the core notches, adjust the guides and, after each loading, feed at least 10 cm of media with FEED.

Likely cause

The GX420t guide states that the core notches must be square to lock the spool properly: a spool that slips causes ribbon creasing. The Zebra article on print quality for the GX, GK and GC Series adds media drifting sideways and a printhead that is not latched.

What to do

1. Check the cores: square notches in good condition, never old cores with notches on one side only.
2. Check that the ribbon is taut over the printhead (left thumbwheel turned backwards).
3. Close the cover and press FEED to feed at least 10 cm of media: slack and creases disappear.
4. Adjust the media guides so that the media does not drift.
5. Check that the printhead is latched on both sides.

Sources: Loading the transfer ribbon (opens in a new window) – Guide d'utilisation Zebra GX420t / GX430t, imprimante thermique de bureau (French user guide; PDF, 980612-021 Rev. C) · Loading Transfer Ribbon (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) · Resolving Print Quality Issues on GX, GK and GC Series Desktop Printers – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems (opens in a new window) (official documentation).

Short answer: According to Zebra, labels that do not lie flat on their backing catch on the guides and rollers, peel off and jam. Clean the platen roller with alcohol; if the labels still stick or jam, it must be replaced.

Likely cause

The GX guide cites poor-quality labels, as well as adhesive and media residue that build up on the platen roller and the printhead and can cause lost labels and jams. The Zebra article on the platen roller for the GX, GK and GC Series states that cleaning is needed when adhesive, dirt or oil make the media slip or stick, and that the roller must be replaced if the jams persist after cleaning.

Caution: Use only a swab or cloth that is lightly moistened, never soaked: according to Zebra, too much alcohol can contaminate the electronic components and greatly lengthen the drying time.

Cleaning and replacing the platen roller (Zebra procedure)

1. Use approved labels that lie flat on their backing.
2. Open the cover (and the peeler door if the printer has one), then remove the media from the platen roller area.
3. Pull the right and left tabs apart, pivot them upwards, then lift the platen roller out of the chassis.
4. Clean it from the centre towards the ends with a lint-free swab or a lint-free cloth very lightly moistened with medical alcohol (at least 90% according to the guide, 99.7% according to the Zebra article); use a new swab if there is a lot of adhesive and throw them away after use.
5. Refit the roller: bearings in place on the shaft, gear on the left; lower it into the chassis and fold the tabs back down until they click.
6. Wait one minute before closing the peeler door or the cover and reloading the labels.
7. If the media still sticks or jams after cleaning, replace the platen roller.

For a long period out of use, Zebra advises leaving a label or a sheet between the printhead and the platen roller, to prevent the printhead from sticking, and never shipping the printer with a roll installed.

Sources: Replacing Supplies (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Cleaning and Replacement for the GX, GK and GC Series Platen Roller – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Platen Cleaning and Replacement (opens in a new window) · Cleaning; Platen Cleaning and Replacement – User Guide Zebra GX420d Desktop Thermal Printer (980611-001 Rev. B, 2008) · Platen Cleaning and Replacement – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (980612-001 Rev. A, 2007) · Long Term Printer In-activity or Storage (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: Fanfold paper and external rolls enter through the rear slot. Adjust the guides with the green thumbwheel; with an external roll, Zebra advises reducing the print speed to limit motor stalls.

Likely cause

Zebra states that it does not offer an external roll option for the GX: the roll and its holder must offer little inertia at start-up so that the printer pulls the paper smoothly. Poorly guided fanfold paper drifts or has its edges damaged on exit.

What to do

1. Open the cover and set the guide stop with the green thumbwheel, using a piece of the fanfold paper: thumbwheel towards you to widen the guides, backwards to narrow them.
2. Insert the paper through the rear slot, pass it between the guide and the roll holders, then close the cover.
3. If the paper drifts or frays, readjust the guides; if that is not enough, pass it over the two roll holder rods. For thin paper, place an empty core the same width as the stack between the holders.
4. With an external roll: feed the paper in through the rear slot, reduce the print speed and check that the paper feeds without slipping, jerking or jamming, that the printer does not touch the roll and that it does not slide or lift off its work surface.

Sources: Printing on Fan-Fold Media (opens in a new window) · Printing with Externally Mounted Roll Media (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: Zebra cites a printhead that is dirty or too cold, incorrectly set darkness or speed, incompatible media, an insufficient power supply, a worn printhead or a slipping platen roller. Clean the printhead with the cleaning pen, then set the darkness with the six-flash sequence.

Likely cause

The “Print Quality Problems” table in the GX420t guide cites a printhead that is dirty or too cold, darkness and speed, incompatible media, a power supply that does not deliver 100 W output (direct current), a worn printhead and a platen roller that is losing its grip (foreign matter, glazed surface, cuts). The Zebra article on print quality adds that print that is lighter on one side comes from a printhead that is not properly latched or from a worn roller.

Caution: The printhead gets hot during printing: do not touch it and use only the cleaning pen to maintain it. Zebra also points out that electrostatic discharge can damage the printhead and the electronics located under the cover. A pen that has already been used can carry contaminants that damage the printhead.

Printhead cleaning and settings (Zebra procedure)

1. Let the printhead cool for about one minute.
2. With a new cleaning pen (one pen is supplied with the printer), rub the dark strip of the printhead from the centre towards the ends, to push the adhesive out of the paper path.
3. Wait one minute before closing the printer.
4. Set the darkness: with the printer ready, hold down FEED until the sequence of six flashes and release it; the printer prints barcode patterns that get progressively darker. Press FEED as soon as the pattern is sharp and readable.
5. If the print needs to be very dark, reduce the print speed.
6. Check that the driver or the application does not impose other values: they can override the settings made with FEED.
7. If one side is lighter, check that the printhead is latched on both sides and inspect the platen roller.
8. Check that the power supply is the one for the GX (see power supply), then clean or replace the platen roller if it is slipping (see platen roller).

Zebra recommends cleaning the printhead with each roll of media. Commands: ~SD (darkness) and ^PR (speed) in ZPL, D and S in EPL. Zebra specifies that the GX, GK and GC Series have no printhead pressure adjustment, and that too high a darkness used to compensate for poor media shortens the life of the printhead.

Sources: GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems; Adjusting the Print Width; Adjusting the Print Quality (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 40, 99 and 107 · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems; Adjusting the Print Width; Adjusting the Print Quality (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 40, 99 and 107 · Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 · Cleaning; Cleaning the Printhead – User Guide Zebra GX420d Desktop Thermal Printer (980611-001 Rev. B, 2008) · Cleaning the Printhead – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (980612-001 Rev. A, 2007) · Thermal Printing (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · What's in the Box? (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Resolving Print Quality Issues on GX, GK and GC Series Desktop Printers – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems (opens in a new window) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) (official documentation).

Short answer: Without ribbon, the media is probably not direct thermal: do the scratch test. With ribbon (GX420t), check that it is coated on its outer side and suited to the media; according to Zebra, print that smears or rubs off comes from a ribbon that is poorly matched to the media.

Likely cause

The “Print Quality Problems” table cites media that is not direct thermal when printing without ribbon, media that is not wound outwards or not approved for printing with ribbon, and incorrect loading. The GX420d prints only in direct thermal mode. The Zebra article on print quality attributes smearing to a ribbon ink that is poorly matched to the media.

What to do

1. Media scratch test: scratch the print side firmly with your fingernail or a pen cap. A black mark indicates direct thermal media; no mark, thermal transfer media that requires a ribbon (not supported by the GX420d).
2. GX420t, adhesive test: press the sticky corner of a label onto the outer side of the ribbon roll, then peel it off; ink on the label indicates a ribbon coated on the outside, which can be used.
3. With no label to hand, ribbon scratch test: place the ribbon outer side against a sheet of paper and scratch its inner side with your fingernail; a mark on the sheet indicates a ribbon coated on the outside.
4. GX420t: check that the print mode is thermal transfer with ribbon, and direct thermal without ribbon.
5. Check that the ribbon and the media are compatible for your application.
6. Check the loading of the media and the ribbon (see labels and ribbon).

Zebra reminds you never to use direct thermal media with a ribbon: barcodes and graphics may be distorted.

Sources: GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems; Adjusting the Print Width; Adjusting the Print Quality (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 40, 99 and 107 · Determining Thermal Media Types (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Ribbon Overview (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) · Resolving Print Quality Issues on GX, GK and GC Series Desktop Printers – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems (opens in a new window) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) (official documentation).

Short answer: According to Zebra, white lines come from dirty or faulty printhead elements. Clean the printhead; if the lines persist, some elements are out of service and the printer needs service.

Likely cause

Dirty or faulty printhead elements, according to the Zebra article on print quality for the GX, GK and GC Series.

Caution: The printhead gets hot during printing: do not touch it.

What to do

1. Clean the printhead with the cleaning pen (see faded print).
2. Print a configuration label (FEED held down until one flash) and check that the box around the text is a continuous line, without any white band.
3. If white bands persist after cleaning, some printhead elements are faulty.

When to call a technician: if printhead elements are faulty, Zebra states that the printer needs service.

Sources: Resolving Print Quality Issues on GX, GK and GC Series Desktop Printers – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems (opens in a new window) · Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 (official documentation).

Short answer: Zebra advises setting the print width when first using the printer, every time the media width changes and when the image is shifted horizontally. Hold down FEED until the sequence of five flashes, then press FEED when the printed box reaches the required width.

Likely cause

Print width not suited to the media. For an image cut off on the right, the Zebra article on print quality also cites a ribbon narrower than the labels or debris stuck to the printhead.

What to do

1. With the printer ready and the cover closed, hold down FEED until the sequence of five flashes, then release it.
2. The printer prints increasingly wide boxes, in 4 mm steps: press FEED once when the maximum width you want has been reached.
3. Check that the driver or the application does not impose a different width: they can override this setting.
4. GX420t: use a ribbon wider than the labels; remove any debris or label stuck to the printhead.

By programming: ^PW in ZPL, q in EPL (page mode).

Sources: GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Adjusting the Print Width (opens in a new window) – Zebra technical documentation (G Series) · Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems; Adjusting the Print Width; Adjusting the Print Quality (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 40, 99 and 107 · Resolving Print Quality Issues on GX, GK and GC Series Desktop Printers – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems (opens in a new window) (official documentation).

Short answer: According to Zebra, too high a darkness widens the bars and narrows the spaces. Lower the darkness, check the quiet zone around the code and make sure that no printhead elements are missing.

Likely cause

The Zebra article on print quality for the GX, GK and GC Series cites three causes: darkness too high, missing printhead elements and insufficient quiet zone. The GX guide specifies that too high a darkness can distort barcodes.

What to do

1. Lower the darkness: six-flash sequence, and press FEED as soon as the printed pattern is sharp and readable.
2. Allow a quiet zone of at least ten times the width of the narrowest bar.
3. Print a configuration label and check that the box around the text is a continuous line, without any white band; if not, see white lines.

Sources: Resolving Print Quality Issues on GX, GK and GC Series Desktop Printers – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems (opens in a new window) · Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 (official documentation).

Short answer: The printhead is a consumable that wears through friction with the media: Zebra advises replacing it when it is worn, after ruling out a dirty printhead, an incorrect darkness setting and incompatible media. With the printer switched off and unplugged, at a workstation protected against static electricity, release the printhead, disconnect its cables and install the new one.

Likely cause

According to Zebra, printhead wear is normal; unapproved media can shorten its life or damage it, and excessive darkness used to compensate for poor media wears it out faster. On the GX420t, a ribbon narrower than the media leaves areas of the printhead unprotected.

Caution: Zebra asks you to switch off and unplug the printer, to protect against electrostatic discharge (grounded conductive mat, anti-static wrist strap) and not to touch the printhead, which gets hot during printing.

Zebra printhead replacement procedure (GX420d)

1. Before concluding that it is worn, clean the printhead and check the darkness (see faded print); on the GX420t, use a ribbon at least as wide as the media.
2. Switch off the printer and unplug the power cord; place the printer on a grounded conductive mat and wear an anti-static wrist strap.
3. Open the printer: release latches pulled towards you, cover raised.
4. Push the right-hand side latch of the printhead to the right, pull the printhead forwards (free it from the cover if necessary), then disconnect the two cable harnesses.
5. Connect the left and right connectors of the new printhead to the harnesses, slide the printhead in on the left side, then snap it into the right-hand latch.
6. Clean the new printhead with a new cleaning pen, reload the media, plug in and switch on the printer, then print a configuration label to check that it works.

This procedure is the one in the GX420d guide. On the GX420t, follow the “Replacing the Printhead” section of its own user guide, which is not reproduced here.

Sources: GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems; Adjusting the Print Width; Adjusting the Print Quality (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 40, 99 and 107 · Replacing the Printhead – User Guide Zebra GX420d Desktop Thermal Printer (980611-001 Rev. B, 2008) · Resolving Print Quality Issues on GX, GK and GC Series Desktop Printers – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems (opens in a new window) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · Loading Transfer Ribbon (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) (official documentation).

Short answer: According to Zebra, flashing green indicates that the printer is receiving data; once the transfer is complete, the light changes to solid green and printing resumes. If nothing comes out, clear the Windows print queue, restart the printer, then check the driver.

Likely cause

The Zebra article, which covers G Series printers, identifies the print queue, the buffer memory, the firmware and the driver as the points to check when the printer receives data without printing. The GX Series set-up article adds that driver or software settings that do not match the printer are a common cause of errors, even after a successful installation.

What to do

1. Wait for reception to finish: the light should change to solid green.
2. Clear the computer's print queue.
3. Switch off the printer, wait a few seconds and switch it back on.
4. Cancel the contents of the printer's buffer memory, then reset it if necessary (see reset).
5. Update the firmware (see firmware).
6. Reinstall the driver, check that its settings (media, width, darkness, print mode) match the printer and print a test page from the driver; if this test succeeds, look for a conflict with the printing application.

When to call a technician: if the problem persists, the Zebra article refers you to technical support; for the GX420, for which Zebra support ended on 30 April 2025 in Europe, Zebra directs you to an authorised service provider.

Sources: The LED on Printer Is Flashing Green but the Printer Is Not Printing – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Status Light Error Resolutions (opens in a new window) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · GX420d Desktop Printer Support & Downloads (opens in a new window) – Zebra website, support and downloads (official documentation).

Short answer: Zebra recommends installing the driver before connecting the USB cable. If the printer appears under “Unspecified”, uninstall the corresponding “USB Printing Support” entry in Device Manager, then run hardware detection again.

Likely cause

According to the GX guide and the Zebra set-up article, the driver must be installed before the USB connection; Zebra advises installing Zebra Setup Utilities before connecting or powering the printer.

Caution: Zebra asks you to switch off the printer before connecting or disconnecting the communication or power cables.

What to do

1. Install the Zebra driver (Zebra Setup Utilities or ZDesigner driver) before connecting the printer.
2. Connect the USB cable: Windows should detect the printer and install its virtual USB port.
3. If it appears under “Unspecified”: open its properties, Hardware tab, select USB Printing Support and note its location.
4. In Device Manager, under Universal Serial Bus controllers, find the USB Printing Support entry at the same location and uninstall it.
5. Choose Action, then Scan for hardware changes: the printer should reappear in the Printers category.

The printer behaves as a USB end device: a scanner or a scale connects to the serial port, not via USB.

Sources: Installing ZDesigner Driver for USB Printer – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Pre-install Windows Printer Drivers (opens in a new window) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · Pre-install Windows Printer Drivers (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: The application is already sending printer code, but it goes through a driver that processes it again and prints it as text. Use the Windows Generic / Text Only driver; if the printer is in Dump mode (communications diagnostics), switch it off and on again.

Likely cause

According to Zebra, an application that produces ZPL or EPL must not go through the ZDesigner driver: the code is then printed in plain text. In Dump mode or communications diagnostics mode, the printer also prints the commands instead of the labels.

What to do

1. If the application generates ZPL or EPL, select the Windows Generic / Text Only driver for the print queue.
2. Do not use the ZDesigner driver, the Zebra universal driver or a third-party driver for this type of output.
3. If the data is in a file, send it directly to the printer, for example by FTP over the network.
4. If the printer is in Dump mode, switch it off and on again.

A standard Windows application, which does not write ZPL, on the other hand needs the ZDesigner driver to convert the label into printer language.

Sources: Zebra Printer Prints Command Language Code, Unrecognized Characters or Text – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Communications Diagnostics (opens in a new window) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) (official documentation).

Short answer: Zebra points out that Windows sets flow control to “None” by default, whereas the printer requires hardware flow control. Use a null modem (crossover) cable, match all the computer's parameters to those of the printer, or reset the serial port to its default values (three flashes).

Likely cause

Different serial parameters between the computer and the printer, in particular flow control. Factory values given by Zebra: 9600 baud, 8 data bits, no parity, 1 stop bit, DTR/XON/XOFF. Zebra uses a null modem cable; the printer automatically detects DTE or DCE wiring.

Caution: Zebra asks you to leave the power switch off while connecting the interface cable.

What to do

1. With the printer switched off, connect the null modem cable (male DB-9 connector on the printer side).
2. In Windows, set the flow control of the COM port to Hardware and match the other parameters to those of the printer.
3. Automatic synchronisation (autobaud): hold down FEED until the green light flashes once, twice and then three times, then send ^XA^XZ while the light is flashing; it changes to solid green once the printer and the computer are synchronised. No label is printed during this phase.
4. Resetting the serial parameters to their defaults: hold down FEED until the sequence of three flashes and release it immediately, then press FEED while the light is flashing rapidly amber and green.
5. Then set the parameters with the ZPL command ^SC or the EPL command Y.

Zebra drivers do not support Windows Plug and Play detection on the serial port.

Sources: Connecting your Printer to a Computer (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · Pre-install Windows Printer Drivers (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: The IP address appears in the lower half of the configuration label (FEED held down until one flash); the ZPL command ~WL prints the network configuration label. On Ethernet, the address can be assigned automatically by DHCP.

Likely cause

Zebra states that the IP address is needed to identify and configure the printer on the network. According to the GX Series set-up article, the Wi-Fi option must first be configured over a local connection (USB, serial or parallel).

Caution: Connect the network cable with the printer switched off, using a Category 5 or higher UTP RJ45 cable.

What to do

1. Print the configuration label: with the printer ready, hold down FEED until one flash, then release it; the IP address appears in the lower half.
2. For the full network configuration label, send the ZPL command ~WL.
3. Ethernet: check the connector lights (both off, no link; green, 100 Mbit/s; amber, 10 Mbit/s; flickering in the other colour indicates activity).
4. Wi-Fi: first configure the printer over a local connection (USB, serial or parallel), for example with Zebra Setup Utilities or ZebraNet Bridge.
5. Enter the IP address in a browser to open the print server's pages. To set a fixed address, the Zebra article describes switching the IP protocol to permanent (Network Configuration, TCP/IP Settings), saving the configuration, Reset Network and then restarting the printer; the login credentials are given in the Zebra print server documentation.

Sources: Printer Network Configuration Status Label (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · ZebraNet Internal Wireless Print Server Option (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Connecting your Printer to a Computer (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) · Using the ZebraNet Print Server Web Page to Configure a Permanent IP Address – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › ZebraNet 10/100 Internal (Wired) Print Server Option (opens in a new window) (official documentation).

Short answer: The label taken sensor is not enabled: without it, according to Zebra, the GX420 stacks and ejects the peeled labels. Enable it in the driver or by command, and check that the liner passes between the peeler door and the printer body.

Likely cause

According to Zebra, printing of the next label waits for the presented label to be removed; this operation requires the label taken sensor to be enabled.

What to do

1. Load the labels, close the cover and press FEED until at least 100 mm (4 inches) of labels come out; remove these labels from their liner.
2. Pass the liner over the top of the printer, open the peeler door and slide the liner between the door and the printer body.
3. Close the peeler door and press FEED to advance the media.
4. Enable the label taken sensor: in the driver, or with the ZPL commands ^MMP or ^JUS, or with the EPL command OP.
5. During printing, remove each presented label: the printer then prints the next one.

The operating mode (tear-off, peel-off or cutter) can also be selected in the driver, according to the Zebra set-up article for the GX Series.

Sources: Label Dispenser Option (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · GX Series Initial Printer Setup Details and Information – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d/GX430d Desktop Printer User Guide (PDF) › Getting Started (opens in a new window) (official documentation).

Short answer: According to Zebra, labels shorter than 25.4 mm (1 inch) between two cuts or media that is too thick can jam the cutter or cause an error. Respect the media limits and never insert any object or finger into the mechanism, which contains no user-serviceable parts.

Likely cause

The medium-duty cutter cuts liner and light tag stock up to 180 g/m². A length between cuts of less than 25.4 mm can cause a jam or an error; exceeding the weight, density or thickness limits shortens its life or can cause it to fail.

Caution: Never remove the cutter cover (bezel) and never insert any object or finger into the mechanism. Do not use tools, cotton swabs or solvents, including alcohol: according to Zebra, they can damage the cutter, shorten its life or cause jams.

What to do

1. Check that the label length between two cuts is at least 25.4 mm (1 inch).
2. Check that the media is within the cutter limits: cutting width from 19 to 108 mm, thickness up to 180 g/m².
3. Reload the media, passing it through the inner slot of the cutter, with the movable sensor (if installed) in its default position, slightly to the right of centre.
4. Leave the self-cleaning cycle active: by default, the cutter makes a cleaning cut every 25 cuts, and Zebra advises against disabling it.

When to call a technician: the cutter contains no user-serviceable parts: if the jam persists, do not remove its cover and call in a technician.

The type of cutter installed is shown on the printer's configuration label.

Sources: Cutter Option (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Cutter Option (opens in a new window) – User Guide Zebra GX420t / GX430t Desktop Thermal Printer (PDF, 980612-001 Rev. C) · Loading Media with the Cutter Option (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: Check the power chain described by Zebra: mains cord connected to the power supply and to the socket, light on the power supply lit (the socket is supplying power), power supply connector pushed into the printer, power switch up. Use the power supply intended for the GX: 24 V DC, 100 W.

Likely cause

The GX guide describes the connection: mains cord to the power supply, cord to the socket, power supply connector to the printer. The light on the power supply comes on when the socket is live. The pages of the guide consulted do not detail a troubleshooting procedure for this case.

Caution: Never operate the printer or its power supply in a place where they could get wet: Zebra warns of a risk of serious injury. Position the printer so that the cord remains accessible: unplugging it is the only way to cut off the power completely.

What to do

1. Push the power switch down (off).
2. Connect the mains cord to the power supply, then to a socket: the light on the power supply should come on; if it stays off, the socket is not supplying power.
3. Push the power supply connector into the printer's power socket.
4. Push the power switch up (on).
5. Check that the power supply is the one for the GX (see power supply).

Sources: Attaching Power (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Operator Controls (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) · Using the Wrong GX, GK and GC Series Power Supply Causes Light Print or Grinding Noises – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) (official documentation).

Short answer: According to Zebra, an unsuitable power supply does not deliver enough power and causes grinding noises and faded print. The GX requires a power supply with 24 V DC and 100 W output; the print problems table in the GX420t guide also asks you to check these 100 W.

Likely cause

Insufficient power delivered by a power supply that is not the one intended for the GX Series.

Caution: Zebra requires a three-pin cord with an IEC 60320-C13 connector, bearing the certification mark of the country of use, and asks you to use only certified adapters with the specified ratings: another adapter can damage the device or put the user at risk.

What to do

1. Check the part number and specifications of the power supply connected to the printer.
2. If necessary, replace it with the power supply approved for the GX Series: Zebra part number P1076001-006, which replaces the former part number 105934-054; auto-sensing, PFC compliant, 100-240 V AC input, 24 V DC and 100 W output.
3. Reconnect the printer and test printing.

Sources: Using the Wrong GX, GK and GC Series Power Supply Causes Light Print or Grinding Noises – Zebra knowledge base (support) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420t/GX430t Desktop Thermal Printer User Guide (PDF) › Print Quality Problems; Adjusting the Print Width; Adjusting the Print Quality (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 40, 99 and 107 · Zebra GX420t / GX430t, regulatory notice and power supply (P980606-014) (opens in a new window) – Zebra GX420t / GX430t documentation (PDF) · Attaching Power (opens in a new window) – User Guide Zebra GX420d / GX430d Desktop Thermal Printer (PDF, 980611-001 Rev. C) (official documentation).

Short answer: With the printer switched on and the cover closed, hold down FEED until the sequence of four flashes, then release it. The light turns amber for three seconds, then the GX420 restores its factory settings, performs a calibration and defragments its memory.

Likely cause

The reset restores the factory defaults (equivalent to the ZPL command ^JUN) and re-enables automatic calibration disabled by a manual calibration. Zebra specifies that some settings are not restored.

Official procedure (four flashes)

1. With the printer switched on and the cover closed, hold down FEED: the green light flashes in sequences.
2. Release it during the sequence of four flashes.
3. The light turns amber for three seconds; if you take no action, the reset takes place automatically.
4. On a printer fitted with a network option, hold down FEED during this phase to choose: releasing after one flash resets only the network, after two flashes only the printer, after three flashes both the printer and the network.
5. The printer then performs a media calibration and a memory defragmentation.

Source: Manual Calibration; Feed Button Modes (Power On Modes) (opens in a new window) – Extract from the GX420t / GX430t user guide (980612-001 Rev. C), pp. 102 and 107 (official documentation).

Short answer: Send the firmware file to the printer, for example with Zebra Setup Utilities (Printer Tools, Actions tab, Send file). The light flashes during the transfer and changes to solid green at the end; then print a configuration label to check.

Likely cause

Procedure from the Zebra page “Downloading Printer Firmware to the Desktop & Tabletop Printers”. Zebra has discontinued the GX420: its support resources can still be consulted but are no longer updated.

What to do

1. Connect the printer to the computer (serial, parallel, USB or Ethernet).
2. In Zebra Setup Utilities, select the printer, open Printer Tools, Actions tab, choose Send file and select the firmware file.
3. On Ethernet, the file can also be sent by FTP to the IP address of the print server (put command).
4. Wait until the light changes to solid green.
5. Print a configuration label to confirm the update.

According to the Zebra support pages, the GX420d and GX420t have no longer been sold since 31 January 2022 in Europe, the Middle East, Africa and the Americas, and their service and support ended on 30 April 2025 in these regions.

Sources: Downloading Printer Firmware to the Desktop & Tabletop Printers – Zebra technical documentation (G Series) (link removed on 21 October 2026: the page is no longer available at its former address) · GX420d Desktop Printer Support & Downloads (opens in a new window) – Zebra website, support and downloads · GX420t Desktop Printer Support & Downloads (opens in a new window) – Zebra website, support and downloads (official documentation).