Zebra GC420 Setup ZPL & Calibration


Download the newest driver for the GC420 printer

The newest Zebra Tag printers of the 420 family introduces two drivers.  One is an older driver (EPL) which is found in the driver name and the newer driver is ZPL which does not show in the driver name once installed.  The printer and driver are found within the Windows printer folder.

   Choose the non (EPL)  driver

The ZPL or non-labled EPL driver should be used.  

If you only see the EPL driver then change to the non EPL driver within the Printer Properties.  Access the printer drop down menu by Right Clicking the printer.

Select the Advance tab and in the Driver dropdown look for a non-EPL driver.

Once the correct driver is being utilized printing can be accomplished.


The newest Zebra Tag printers of the GC420 family requres adjustment (Calibration) when tag stock is exchanged in the printer.  

When switching stock in the printer insure the printer is turned off.  By default the printer attempts to auto calibrate to the label stock installed with the printer is turned on and while status light is becmes solid green.  Once the light is solid green - Press feed button, wait till stock paper stops moving and press Feed button again.  If the label stops where it should then perform a test print and that is ok you are good to go.  If this does not adjust the printing properly then the printer must be manually calibrated.

Zebra offers two ways to calibrate the printer to the stock inserted.

First.  Turn printer off.  Insert the label stock, label/tag print side facing up.    Then, turn the printer power on if you have not already done so. If the printer initializes with the status light blinking green (pause mode), press the Feed button once to set the printer in Ready (to print) mode (light is solid green).

1)  Manual calibration via the Feed button located on the printer (see illustration below for feed button location) is recommended whenever  the printer will not correctly auto calibrate/print onto a tag/label.

With the printer power on and top cover closed, press and hold the Feed button for several seconds. The green status LED will flash a number of times in sequence.  The sequence starts at 1 flash and progresses upto 7 flashes. Release the key after the  specific number of flashes and before the next flash sequence starts to perform a task.

Status Light flash sequence for auto calibration
*      (flash once, pause)
**    (flash twice)  Release the feed button

Standard Auto Media Calibration - The printer detects and sets media type and media length, and it adjusts the media sensors for optimal performance with the installed media (equivalent ZPL command ~JC  ~JG). The printer will feed one to four labels while calibrating.

2)   Calibrate via the print driver

Use the driver calibration method when the printer does not feed/print the labels properly or when you change from labels without a black bar printed on the labels to labels with a black bar (like the bell jewelry labels) anjd the manual claibration in step 1 does not work.

To calibrate navigate to the Zebra DC420 driver in the Windows Printer folder and right click then choose Printing Preferences. 

Then click on the  Advance Setup tab.  Use Web Sensing with tags that do not contain a Black Bar printed on the back (bell jewlery labels).  Use  Mark Sensing for labels with a black bar.  After a change click APPLY.


Next click the Other button and insure Default Settings are selected.  Click Close

When the Advance tab re-appears click Calibrate and the printer should perform the Calibration with the new settings.

These steps should only be peformed if the Manual calibration does not work in step 1 or tags are switched between those with black bars and those with. 

Any calibration will feed a few labels out to perform the calibration.  When the printer completes and the light is solid green then open the printer to roll back the tags back onto the roll. Close lid and press the feed button once to position the label/tag to the beginning.

Set to printer Defaults, in case above steps fail to calibrate try resetting the printer to factory defaults.

*        (flash once, pause)
**      (flash twice, pause)
***     (flash three , pause)
****   (flash four) Releaase the feed button

Test printing.  If printing is still not correct try resetting to Factory defaults!

Factory Defaults - Resets the printer to the factory default settings (equivalent to ZPL command ^JUN). See Appendix: ZPL Configuration on page 81 for a description of the primary 
configuration settings and their associated ZPL commands. Some configuration settings are not returned to their initial ‘out of box’ settings. Other settings are exclusively set, viewed and controlled by programming are also reset. The printer then performs a standard media calibration followed by .a memory defragmentation routine.

*              (flash once, pause)
**            (flash twice, pause)
***          (flash three , pause)
****        (flash fou, pauser)
*****       (flash five, pause)
******      (flash six, pause)
*******    (flash seven) Release the feed button

Manual Media Calibration - The printer runs extensive tests to detect and set media type and media length, and then it adjusts the media sensors for optimal performance with the installed media (equivalent ZPL command ~JG). Manual calibration is recommended whenever you are using pre-printed media, print on the liner or if the printer will not correctly auto calibrate. A graphical profile of the media sensing will print. See Manual Calibration on page 66 in Zebra manual for more details and considerations.

Note:   Performing a manual calibration disables the auto calibration function. To return to auto calibration, default the printer.  Also this function will print on many tags during the process.

If all these fail please contact BBL support.

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