If it is a complete printer, then it doesn't much matter if it is a thermal printer, or dot matrix impact printer, or ink jet or any other method. What you should have specified then is a RS232 printer, or a USB printer or a ...

If asking how to interface something, you must include in your question the relevant facts needed for anyone to be able to answer. Do you have logic-level signals to interface, the answer will be completely different from if the device you have is using a specific and well standardized/documented serial or parallell interface.

So, it may take a bit of time to figure out what is the relevant information to write in the question. But that is the same relevant information that you need to collect, if you are going to Google for possible solutions. So in the end - it doesn't matter if you find a solution yourself, or ask someone else for help. You still have to spend the time figuring out a number of details about your printer.

Specifying a make and model of the printer would help.