Tamir Mironov

Zebra Label Printer with Python

This project presents a robust and user-friendly Zebra Label Printer application, developed using Python and the Tkinter GUI library. Designed for efficiency in manufacturing and logistics environments, this tool streamlines the process of generating and printing ZPL (Zebra Programming Language) labels containing critical product information, including serial numbers and QR codes.

You can find my code here: GitHub

Key Features:

  • Intuitive User Interface: A clean and organized GUI built with Tkinter ensures ease of use, allowing operators to quickly configure print settings and manage serial numbers.
  • Dynamic ZPL Generation: The application dynamically constructs ZPL strings based on user inputs for product name, part number, and serial numbers. This includes:
  • Product Name & Part Number: Customizable fields for product identification.
  • Barcode 128: Automatically generates a barcode for the part number.
  • DataMatrix QR Codes: Creates individual DataMatrix codes for each serial number, arranged in a clear grid for easy scanning.
  • Batch QR Code: A large QR code at the bottom consolidates all serial numbers in the current batch, enhancing traceability.
  • Adjustable Offsets: Fine-tune the placement of QR codes and serial numbers on the label with X and Y offset controls, ensuring perfect alignment on various label sizes.
  • USB Printing Capability: Leverages the pywin32 library to directly interface with Zebra printers connected via USB, providing a reliable and direct printing solution.
  • Batch Printing with Auto-Print: Supports collecting up to 12 serial numbers per batch and offers an auto-print feature that triggers printing once the maximum count is reached, optimizing workflow.
  • Reprint Functionality: Includes a “Print Last Batch” option for quick reprinting of previously sent labels, useful for quality control or if a print job fails.
  • Serial Number Management: Easily add, delete, and clear serial numbers from the current batch. The application prevents duplicate entries and provides real-time feedback.
  • CSV Logging: Automatically logs all printed serial numbers, along with timestamps and batch information, to a CSV file for comprehensive record-keeping and auditing. A built-in viewer allows users to inspect the log directly from the application.
  • Comprehensive Help Section: An integrated help guide provides clear instructions on printer setup, usage, and troubleshooting.

This project demonstrates proficiency in GUI development, external library integration (pywin32 for printer interaction), data management (CSV logging), and string manipulation for specialized printer languages (ZPL). It stands as a practical example of how Python can be used to build effective desktop applications for industrial automation tasks.

Enhanced Zebra Label Printer  (Python GUI with ZPL and Win32 API Integration)

This project presents an advanced Zebra Label Printer application, developed using Python and the Tkinter GUI toolkit. Engineered for precision and scalability, this tool automates the generation and direct printing of ZPL (Zebra Programming Language) labels, catering to the rigorous demands of manufacturing, warehousing, and logistics environments.

Architectural Overview:

The application follows a standard Model-View-Controller (MVC)-like pattern, albeit implicitly. The ZebraPrintApp class serves as the primary controller and view, managing the user interface and orchestrating interactions. The core logic for ZPL string generation and printer communication is encapsulated in dedicated functions, promoting modularity and reusability.

Core Technical Details:
  • GUI Framework: Built entirely with Tkinter, Python’s de-facto standard GUI library. This provides a native look and feel on Windows and ensures cross-platform compatibility for the application’s interface (though pywin32 limits direct printing to Windows).
  • ZPL (Zebra Programming Language) Generation:
    • The generate_zpl_string function is the heart of the label creation. It meticulously constructs ZPL II commands to define the label layout and content.
    • It dynamically positions and sizes elements such as text fields (^FO, ^A0N), Barcode 128 (^BCN), and DataMatrix QR codes (^BQN).
    • A key feature is the ability to embed up to 192 serial numbers into a single, large DataMatrix QR code. This is achieved by concatenating serial numbers and strategically inserting ZPL line break control characters (\x0A) every 16 characters within the QR code data string (^FDLA,...), optimizing data density and scan efficiency.
    • User-configurable offsets (X and Y coordinates) are directly translated into ZPL’s dot-based positioning system, offering precise control over the final label output.
  • Direct Printer Communication (Win32 API):
    • For USB connectivity on Windows, the application leverages the pywin32 library, specifically the win32print and win32api modules.
    • The print_label_usb function establishes a raw print job by calling win32print.OpenPrinter(), win32print.StartDocPrinter(), win32print.WritePrinter(), win32print.EndPagePrinter(), and win32print.ClosePrinter().
    • The ZPL string is encoded as UTF-8 before being sent as a “RAW” data stream directly to the printer spooler, bypassing printer drivers’ rendering engines for maximum compatibility and speed. Error handling for pywintypes.error (specific to pywin32) and general exceptions ensures robust operation.
  • Serial Number Management & Logic:
    • The application maintains a list of collected serial numbers (self.serial_numbers) and the last printed batch (self.last_printed_sns).
    • Input validation prevents empty or duplicate serial numbers and enforces a maximum batch size of 192.
    • The add_serial_number method intelligently segments long serial number inputs into 16-character chunks for individual processing and display in the Tkinter Listbox.
  • Data Persistence & Logging:
    • Printed serial numbers are logged to a CSV file (printed_serials.csv). This is implemented using Python’s built-in csv module, handling file existence checks and appending new records.
    • Each entry includes a batch counter, timestamp (using datetime module), and the individual serial number, providing a comprehensive audit trail.
    • A simple CSV viewer implemented with a Tkinter Toplevel window allows users to inspect the log data directly.