I did spent several hours "webbing" this issue, what I can say about is this:
1) The tablet MUST HAVE usb host mode, otherwise it will never connect
2) Plain text is very easy to print, just open a serial connection for the usb and send it, it works fine.
3) Canon, HP, Epson, Samsung, Zebra, Star and so many others printers manufacturing companies has made apps to print with their printers from an android device, so ... clearly it's possible.
4) Exist several apps in google play store to print by wifi, bluetooth, cloud or even usb, some of then are free, some others you have to pay, none of these are expensive (I think U$S 13 is the most expensive i founded) and before buying anything you can try them with your android device and your printer.
The goal will be to "create" a library for each brand (if it work for several brands will be better) that we can use in our projects to print, I don't mind to pay for it, if someone can do this it will be great, I can't, it's over my knowledge level
Thanks