G Series GK Models: Calibrating the Printer

Article ID: 11996636

Issue / Question

How to resolve flashing red buttons, print drift, or label stopping, skipping, and not lining up on GK420 Series printers?

Applicable To

GK420T and GK420D

Resolution / Answer

CALIBRATION: Ensures correct and consistent positioning of the print on the label and the label in the printer.

Symptoms addressed by this solution include: 

  • The printer prints, then skip a label or skipping labels.
  • The print is overlapping onto the next label.
  • Print position is drifting up and down on the labels.
  • Labels stop printing in random locations.
  • The printer prints labels then the light starts to flash.

Calibrate the printer for the media.

The printer does not measure the label length unless the default Power Up or Head Close values are altered to either Length or Calibrate.

There are two calibration methods to consider if the labels fail to calibrate properly.

  • The 2 Flash Feed Button sequence will find the label gap and measure the label.
  • The 7 Flash Feed Button performs a deeper analysis of the gap or mark and will produce a media sensor profile.   

Refer to this article: G-Series Feed Button Modes.

IMPORTANT! All printer settings may be impacted by commands from a mismatched or misconfigured driver or software application. A printer that is functioning well after setup but fails or indicates an error after label requests are received is most likely affected by the host side misconfiguration of the driver or printer software settings. The host device that generates the printer commands for printing typically has a setup configuration that sends these as commands to the printer. Ensure all settings match the printer settings to avoid intermittent issues.

Media Related Settings and Calibration 

NOTE Printer Setup and Configuration

The GK-Series printer can be configured by your driver, host application, or a utility. The ZebraDesigner Driver is used as an example to configure the printer.
(The configurations are sent when printing using the driver or printing the driver test page).

If you are using a non-Zebra application, driver, or label software, kindly determine the methods used to set these configurations, and be aware the terminology for each setting in your environment may be different.

Understanding Your Media 

The Zebra Printer supports the use of many types and shapes of labels or tags. Knowing your media details is important for proper configuration. 
Here are the details you should know for printer media setup and configuration. In these examples, the ZebraDesigner Driver is used to show the configuration selections for each topic discussed below.   

NOTE When using ZebraDesigner Driver, the configurations are sent to the printer when you request to print a label. (E.g: Printing the Windows Test page will send the printer configurations).


Media Related Configurations

Media Type (Tracking Mode) 

  • Web Sensing (gap) - By Default
  • Continuous 
  • Mark Sensing (Black Mark) 

If you are using media with an inter-label gap or a center hole set the Tracking Mode for Web Sensing.
If you are using media with a black bar or mark set the Tracking Mode for Mark Sensing.

Print Method (Media Type) 

  • Thermal Transfer (Using Ribbon) - By Default
  • Direct Thermal (No Ribbon) 
NOTE The Print Method does not apply if your printer is a GK420D Direct Thermal only. There are no ribbon spindles or settings.


Print Mode

  • Default- Tear Off 
  • Peel (Dispense) 

This is related to the label presentation after printing and is limited to the options you have installed.  

The GK Series Printer supports Tear Off, and Peel (Dispense option required). For more information, refer to Print Mode Details.

Media Loading:

The media must be properly loaded for the Print Mode you intend to use.


Understanding the Media Sensors

The printer comes with sensors for label tracking based on the Media Type used. 
There is a reflective and transmissive sensor positioned slightly off-centered in the media path. 
The sensor you will use requires configuration of the Tracking Mode (Mark/Web/Continuous) setting to function with the media you are using. 
A hole or black mark must pass over the media sensor's position to function correctly.

See the GK Series Printer Sensors:


Media Feed Power-Up Action

The first time you load the media, you should run the 2 Flash Calibration method as described above.
The Media Feed setting then determines how the media is handled when the printer is powered on or when the printhead is opened and closed. 
The printer defaults to feed one label after power-up or when the printhead is opened and closed. 
This is intended to position an already calibrated label to its resting position to be ready for printing. 

This can be altered using the Media Feed setting to one of the following:

  • Calibrate 
  • Feed (Default)
  • Length
  • No Motion
  • Short Cal

If you wish to alter the default setting, you can create a file using the ^MF command to change the values. If you do not want to alter the printer defaults, you can use the 2 Flash calibration each time you change label lengths. See Calibration below:

Setting the Media Feed (Power Up Action) on the printer requires sending the ^MF command to alter the Power Up Head Open value. 

Sending a file using the ZebraDesigner Tools feature. Refer to this article: ZebraDesigner Driver and the Send File Feature.

^MF (Media Feed command). Programming Guide: ZPL Command

An example of a ZPL Media Feed Command to Measure the Label Length when the head is closed.


(Power Up = no motion, Head Close = Measure the length)


(Saves the value)

For recommendations on these selections, refer to Media Feed (Power Up Action/Head Close Action).


Helpful Information:

+ Product Codes

  • G-Series GK Desktop Printers
  • GK420 Healthcare Desktop Printers
  • GK420d Desktop Printer
  • GK420d Healthcare Desktop Printer
  • GK420t Desktop Printer
  • GK420t Healthcare Desktop Printer