Control a dot matrix printer

[Clement_2000]

Hello,
I've recently got two of these amazing dot matrix printers. They support text data and ASCII commands control them.
So, I'd like to make a GUI to control it using... eh... Python of course !
The point is that I know how to send text data to the printer, using :

variableOfYourChoice = open("LPT1", "w")
variableOfYourChoice.write("Your text")
variableOfYourChoice.close

but now I'd like to send ASCII or decimal commands to them so I can change the print quality, text size, font, text format, control paper, etc... For you to understand what I'm explaining, here is the list of the compatible commands (I have the ML320E and ML390E printers), they are in the tables starting at page 12 : OKI Microline printers compatible commands list
How am I supposed to do that ?

Thank you in advance for your replies,
Clément.