From http://www.rongtatech.com/download.aspx you'll get a .rar for your RP80. In that .rar, there's a directory called "80 Manual" and from there a file called "80 command set.pdf". This will provide you with all of the escape sequences required to design whatever ticket you want to produce. For instance, switching to Greek is a matter of sending Esc t 17 (from the manual)
As for graphics, it can print graphics according to the manual, but as is common, you will probably need to convert to a .PCX or .BMP format. I used to do this for Zebras, but that was 20 years ago. Not complex once you've done the first one...
You are now just asking about how to handle images on TCanvas. Try doing some reading, perhaps starting with http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Creating_Drawing_Spaces
or the documentation for TCanvas.
Be aware that Peter's helpful comments apply when you are driving the printer directly rather than via the Windows printer driver. Your earlier postings suggest you are not doing this.