ESC/P2 enquiry

Does anyone have a simple example of an Epson ESC/P2 instruction sequence
that will print something in graphics mode. I've got an Epson C64 to print
text ok but it's dead whenever I try to print any image data in graphics
mode - although linefeeds etc work fine. After juggling around with
different instructions with different valued arguments in different orders I
wondered if there are some working routines I could adapt to print a graph.
The instrument isn't a PC or a Mac and has no printer driver.

Best Wishes

Clive Higgs