This is how scrapbookers do it. Type your letters or phrase using word processing software. Print it on regular paper first. Tape the ribbon exactly over the printing and run it through your printer again. It should print on the ribbon just fine.
I would go to the website for your printers manufacturer to see if it is possible, or how to do it. Or go to the manufactuer of the ribbon to see if they have instructions.
I used to print letters on ribbons when I worked for a Hallmark Store but we used a Hot stamp machine. (The same one we used to print on napkins.) I've never seen this done on a regular computer and printer though. You might go to the website for your printer manufacturer and ask them about it.
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