Install a thermal printer driver on Windows.

Most billing software, desktop GST programs and browser-based billing alike, prints a bill the way Word prints a page. The page goes to a Windows print queue, and that queue needs a driver to turn the page into something the printer understands. With no driver there is no queue for the printer at all, or a queue that sends A4-shaped output.

Windows' built-in class driver only covers Mopria-certified printers, and budget 58 or 80 mm thermal printers are usually not on that list. So the maker's driver is the normal route. It is often called something like POS-58, POS-80 or POS-80C.

Search for a printer driver and the first page is mostly driver-download sites. Their installers can be old, for the wrong model, or bundled with other software. Microsoft's own advice is to go to the maker's website. These are the official pages, each opened and checked on 23 Sept 2026.

Maker not listed? Check the CD in the box or ask your dealer. If your USB printer shows up as a COM port, it has a USB-serial chip that needs its own driver, such as WCH's CH340/CH341 driver (official page).

A "Windows can't verify the publisher" warning is common with small makers' packages. It is fine when the file came from the maker's own site. Do not switch off Windows' driver signature enforcement to get past it.

Route 1: the maker's installer (try this first)

1. Right-click the downloaded file and choose Run as administrator.
2. Pick your model and the port (next section).
3. Some makers want the driver installed before the USB cable goes in. Star documents exactly that, so leave the cable out until the installer finishes.
4. Epson's APD6 asks for a port type (Serial, Parallel, USB, Ethernet) and creates its own USB port. It cannot add a USB driver while the printer is offline, for example with the cover open or the paper out.

Route 2: the download is only .inf files

1. Windows 11: Settings → Bluetooth & devices → Printers & scanners → Add device. Windows 10: Settings → Devices → Printers & scanners → Add a printer or scanner.
2. When the printer is not found, next to The printer that I want isn't listed select Add a new device manually.
3. Choose Add a local printer or network printer with manual settings and pick the port.
4. Press Have Disk, browse to the downloaded folder and select the .inf file. Pick the model, name the printer, Finish.

A correct driver on the wrong port prints nothing. Match the port to the cable:

Worked yesterday, dead today? Someone probably moved the USB cable. In Printer properties → Ports, tick the other USB00x and print the test page again, then keep the cable in that one socket. For a counter, Bluetooth is the weakest link: use USB or LAN.

Settings → Printers & scanners → your printer → Printer properties → General tab → Print Test Page. It comes out as one long slip.

• It printed: the driver and port are right. Choose this printer in your billing software.
• Nothing came out: try the other port, and check the cover and the paper. If the job is stuck in the queue, see printer offline or stuck on Windows.
• Strange symbols: the driver or emulation is wrong. See printer prints garbage.

In Printer properties → Printing Preferences → Advanced (or Paper/Quality), pick the paper size that matches your roll. The names differ by driver: Star calls it "72mm x Receipt", POS-80 drivers list an 80 mm width with a long page length, 58 mm drivers a 58 mm width. Choose whatever your driver lists for your roll.

To make it the default, turn off Let Windows manage my default printer in Printers & scanners, then choose Set as default on the thermal printer. Browser billing and Chrome's kiosk printing both print to the default printer, so this matters.

Bill still tiny or half-width from a browser? Chrome has its own settings on top of the driver's: print a proper receipt from Chrome or Edge.

On POS-80 style drivers the cutter and cash drawer options sit in Printing Preferences or on the Device Settings tab of Printer properties. Wording varies by driver: something like "cut at document end" for the cutter, and "open before printing" or "after printing" for the drawer. When the billing software prints through the driver, switching these on is often the whole fix.

• It never cuts: many 58 mm printers have no cutter, only a tear bar. More in printer does not cut the paper.
• The drawer stays shut: the drawer cable goes into the printer's DK port (RJ11), not the computer. Then switch the drawer option on in the driver.

Windows includes a Generic / Text Only driver: in the manual Add printer steps, pick the maker "Generic" and the printer "Generic / Text Only". It passes plain text through, and passes ESC/POS through too when the billing software sends it.

• Enough: when your billing software sends ESC/POS itself, as many desktop POS programs do.
• Not enough: browser billing, or any program that prints a page. No logo, no graphics, no automatic cut, and usually no ₹ sign.

So the maker's driver comes first, and Generic / Text Only only when nothing else is available.

Windows protected print mode. When this Windows 11 setting is switched on, it removes printers that use a maker's driver and blocks reinstalling them while it stays on. If a receipt printer vanished after someone clicked Set up there, this is why. Turn it off in Settings → Bluetooth & devices → Printers & scanners → Printer preferences → Windows protected print mode (if your IT set it by policy, ask them), then reinstall the driver.

Windows Update will not find the driver. From 15 Jan 2026 Microsoft stopped publishing new third-party printer drivers through Windows Update for Windows 11. Drivers installed from the maker's package keep working, so the maker's site is the place to get one.

"Driver is unavailable" means the queue exists but its driver is missing or broken. Remove the printer, download the driver for your Windows version (64-bit) from the maker again and reinstall.

Everything above exists because your software prints through a Windows driver. The EasyKOT register does not. It is built to talk to network (port 9100) and USB thermal printers directly: no maker driver to find, no port to pick, no paper-size dropdown.

In the register open Settings → Printers & KDS and press Detect printers (or Set up a new printer for the guided path). The register looks for the printer in four rounds and shows each one on screen as it runs:

1. “Checking this computer’s USB and Bluetooth ports…”
2. “Trying the printers’ factory addresses…”: a new printer often ships on its maker's fixed address (Xprinter 192.168.123.100, Rongta 192.168.1.87, TVS 192.168.0.31), so the register tries those directly, along with your router's own address.
3. “Asking the network which printers are here…”
4. “Sweeping the Wi-Fi for anything on port 9100…”

Each device it finds carries a plain reason underneath, such as “Answered a receipt-printer command — this is a printer”. Pick yours, choose 80mm or 58mm, press Print a test slip. That is the setup.

Detect printers found the printer on the network and says why. No driver was installed.

• USB printers: on Windows the register uses Windows' own built-in USB printing driver, so there is no maker driver to install.
• Already installed in Windows? In Add manually, pick Windows printer (driver queue — no live status). It prints, but through that route the register cannot see paper-out or an open cover, so Network or USB is better when you have the choice.
• The bill is saved before it prints. If the printer is off, the sale is not lost: the ticket waits in the print queue and retries by itself, up to twelve tries.
• Check printer asks five questions in one go: power and network, cover, language, health and a test slip.

Check printer: five checks, each with a plain result.

Honestly: no printer model is certified by us yet. Our real-hardware record so far is a USB print on the Mac register on 17 Sept 2026. So we do not say "works with brand X"; the ten-second test slip is the proof for your printer. Full walk-through: connect a thermal printer to EasyKOT. Get the register from the download page.