Getting Started

This is a tutorial for web developers to add a plugin to your web page capable of sending raw commands to your printer. This is common for Barcodes, Thermal Printing, Point-Of-Sales (POS), and other commercial/industry purposes.

This is possible by using JavaScript to talk to the QZ Tray or QZ Print software using techniques supported provided by all major web browsers and all major Desktop operating systems.

Note: Legacy version of the software used the Java Applet technology which has since been disabled in Google Chrome. These legacy versions are still supported, but won't work in Chrome after September 2015 due to the removal of NPAPI from the Google Chrome we browser. Firefox, Safari and Internet Explorer still remain compatible with the Java Applet. More details about this change are here: https://qz.io/qztray/

##Preliminary Steps

This tutorial assumes you have already successfully completed the following tasks:

1. QZ Tray is installed and is working properly in the web browser

   • Download QZ Tray

   Legacy Users: If you are not using QZ Tray and having trouble getting qz-print to load properly, follow the tutorial below:

   • Legacy Import Certificate

2. Your printer is connected as a raw print queue on your workstation with the name "zebra" (this can be changed later). Click on the appropriate link below for instructions.

   • Setting Up a Raw Printer in Windows
   • Setting Up a Raw Printer in OSX
   • Setting Up a Raw Printer in Ubuntu Linux

When these two steps have been completed, please move on to the next part of this tutorial.

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##The Code

If Java is installed and working properly with the browser, the page display should be gray and not yellow (as shown below). We are now ready to dive into the code behind qz print.

We will be looking at the sample.html file provided with the qz-print download. This file provides many sample buttons and features.

Detecting readiness

1. Upon load, the function qzReady will be called automatically.

  function qzReady() {
     if (!qz) {
       document['qz'] = document.getElmementById('qz');  // Legacy Applet Usage
     }
     
     try {
       qz.getVersion(); // Validate communication
       alert("Working!");
     } catch (err) {
       alert("Not working! " + err);
     }
  }

Finding the printer

This sample function can be used for both Raw and PostScript Printing.

qz-print's parameters are set through JavaScript commands.

1. Insert (or modify) the JavaScript code to search for a printer named "zebra". The printer name can be anything you wish (ie. "Epson", "Citizen", "Generic", "BOCA", etc.).

   function findPrinter(name) {
      qz.findPrinter("foobar");
   }
   
   function qzDoneFinding() {
      if (qz.getPrinter()) {
         alert("Printer " + qz.getPrinter() + " found.");
      } else {
         alert("Printer foobar not found.");
      }
    }

   • See also sample.html section findPrinter()

   Note: To select another printer, you can also choose it by index using qz.setPrinter(index);

2. Use html code for a Detect Printer button using standard HTML input button. This button has already been provided in sample.html.

<input type=button onclick="detectPrinter()" value="Detect Printer"></input>

1. To test the Find Printer button do the following:

• Load page in web browser and click "Find Printer"

• View Java console for output. Look for "INFO: Printer found..."

  In the image below, "XPS" was searched and successfully detected by the script.

  

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###Raw Printing / PostScript Printing

Depending on what type of printer you have, various functions can be used.

1. Raw Printing

The Raw Printing Guide goes over how to do the following with a Raw Printer:

• Sending Raw Commands (Java / php)
• Base64 Printing
• Epson/Citizen ESC/P Printing
• Advanced Print Spooling
• Print Special Characters
• File Printing
• XML Printing

1. PostScript Printing

The PostScript Printing Guide goes over how to do the following with a PostScript Printer:

• Print to a File
• HTML Printing
• PDF Printing
• Printing Images

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###Serial Communication

1. If you would like to send and receive commands through a serial connection, please read the Serial Communication tutorial.