WebZLP

Windows Printer Driver Conflicts

The Windows driver model works differently from other operating systems and will, by default, use a printer driver for USB printer devices.

While this is useful for most users, WebUSB relies on the browser being able to communicate direcly to a USB endpoint. The default driver Windows will assign to a printer prevents this.

A full explanation of how WebUSB, the browser, and the operating system communicate are out of scope for this library. The Build for WebUSB article goes into more depth.

Workarounds

Different operating system

The simplest workaround is to use a different operating system. ChromeOS, Linux, macOS, and Android can all make use of WebUSB without needing to deal with driver issues.

If you are making an equipment purchase decision strongly consider using something other than Windows devices for this application. For example, ChromeOS devices make for good ‘check-in kiosk’ devices for checking attendees into an event that requires label printing.

Replace the driver

You can use a debug tool to replace the driver with a different version. This is a summary of this guide.

  1. Plug in your printer and connect it to your Windows machine, letting it automatically install the driver.
  2. Download the latest verison of Zadig (or from GitHub).
  3. Run the Zadig executable.
  4. Select Options -> List All Devices.
  5. Select your printer in the device list.
    • Your printer may not be named what you expect. I have an LP2844 that calls itself a TLP2844 in this list.
    • You may have a Windows Notification that shows the name of the device if it was the first time being installed.
  6. Confirm the interface indicates you’re replacing the usbprint driver with the WinUSB driver.
  7. Click Replace Driver.
    • You may be prompted with a bright red warning that the driver isn’t trusted. This is because Zadig generates a new self-signed driver on the fly. You may need to change your Windows settings to make this work if you don’t even see a prompt and just get an error.
    • Click ‘Install this anyway’ to proceed.
  8. Wait, the process is not immediate.

Once complete the printer should be able to be paired in your browser.

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