Easy Thermal PrintEasy Thermal Print Guides
My thermal printer won’t print right: causes and fixes
Quick answer
- Print the printer’s self-test (with it off, hold FEED and turn it on). If that prints fine, the printer works and the problem is the connection or the app.
- Blank paper? The roll is upside down: the side that darkens when you scratch it with a fingernail goes toward the print head.
- Strange symbols? The app isn’t speaking ESC/POS, the language almost every receipt printer uses, or the printer uses its own system (“cat printers” and Niimbot-style label printers).
- A stray letter or number at the end of each ticket? The app is sending the cut command to a printer without a cutter: turn automatic cutting off.
Something else? Find what you see.
We make Easy Thermal Print, the free app used in step 4. The causes and fixes apply to any app.
What you need: The printer, with thermal paper and charged · The Android phone you print from · Five minutes
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Narrow it down: print the self-test
The self-test is a page the printer prints on its own, with no phone. On most models: turn the printer off, hold FEED, turn it on and let go. On some you hold FEED for a few seconds with the printer on; if yours does neither, the manual explains how.
If the self-test comes out sharp, the printer, its head and the paper are fine: go on with steps 2 to 4. If it comes out blank, too light or cut off, the problem is the paper or the printer: start with step 2 and Prints badly.
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Check the paper and the cover
Thermal paper prints on one side only. Scratch the paper quickly with a fingernail: the side that turns dark must face the print head. A roll loaded upside down is the most common reason for blank paper.
Use thermal paper of the right width (58 or 80 mm) and close the cover firmly: many printers won’t print if it is slightly open. Old, damp or very cheap paper prints light even when everything else is fine.
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Check the connection
Bluetooth: most printers accept one phone at a time. Turn off Bluetooth on any other phone or tablet that used it and close other printing apps. If it still fails, remove it in Settings → Bluetooth and pair it again.
WiFi or network: the phone and the printer must be on the same network. If the printer got a new IP address (after a router restart, for example), add it again in the app.
USB: you connect it with an OTG adapter, and the printer needs its own power. When Android asks whether to allow access to the printer, tap OK: if you tap Cancel, the app can’t print. Android asks again every time you unplug the cable.
Not connected yet? Follow the Bluetooth guide or the USB guide.
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Print a test page from the app
A test page shows at a glance what is wrong: edges cut off, too light, or strange symbols.
With Easy Thermal PrintOpen the printer in Printers, tap Print test page and answer Did it print well? If not, tap what you see (Edges cut off, Too light, Strange symbols or Stops halfway): the app changes the setting and you print the test again.
Find what you see
Nothing prints
The app says it printed, but nothing comes out
Check the paper, the cover and the battery. If the printer is paired with another phone, or another app is holding it, it won’t get the job: close that app or turn off Bluetooth on the other phone.
The self-test prints, but the phone can’t print
Android can’t print to receipt printers on its own: its print menu is for office printers. You need an app that speaks ESC/POS, such as Easy Thermal Print.
Over USB it says “USB access was not allowed”
You tapped Cancel when Android asked for permission, or the prompt closed by itself. Print again and tap OK.
Prints badly
The paper comes out blank
The roll is upside down. Do the fingernail test from step 2 and flip it. If the self-test is also blank with the roll the right way, the paper may not be thermal.
It prints strange symbols
Tap Strange symbols after the test page. If nothing changes, the printer probably doesn’t use ESC/POS: “cat printers” and Niimbot-style label printers only work with their maker’s app.
Accents or emoji come out as “?”
Many printers lack those characters. Easy Thermal Print prints them correctly even if your printer doesn’t have them.
The print is too light
Tap Too light once or twice. A low battery and old or cheap paper also give faint prints.
White vertical lines
Usually dirt on the print head. With the printer off and cool, wipe the head with a cotton swab and isopropyl alcohol, and let it dry before closing.
Cut off, or something extra
It stops halfway
Over Bluetooth this is usually a low battery or too much distance: charge the printer, move closer and tap Stops halfway, which sends the data more slowly.
The edges are cut off
Check that the paper width you chose matches your roll (58 or 80 mm) and tap Edges cut off.
A stray letter or number prints at the end
The app sends the command to cut the paper and your printer has no cutter, so it prints it as text. In the printer settings, under Paper cutting, choose Manual.
Tearing by hand loses the end of the ticket
On counter printers the tear edge sits far from the print head, so the last lines stay inside. If your printer cuts by itself, choose Automatic under Paper cutting; if not, raise Blank lines at end under Advanced.
Frequently asked questions
How do I know if my printer uses ESC/POS?
Almost every 58 and 80 mm receipt and POS printer does, such as the PT-210, MTP-II, Xprinter models or the Epson TM-T20; the manual or the box usually says ESC/POS. “Cat printers” and Niimbot-style label printers use their own systems.
Why is the paper blank when the printer sounds like it is printing?
Because thermal paper prints on one side only and the roll is upside down. Scratch the paper with a fingernail: the side that darkens faces the print head.
Why does a B or a 0 print at the end of every ticket?
It is the paper cut command, which a printer without a cutter prints as text. Turn automatic cutting off in the app you use.
Do I need internet to print?
Not over Bluetooth or USB. Over WiFi the phone and the printer only need to be on the same network, even if that network has no internet.