Help!: Output to Printer

Hi, I want to print on paper a string that is in a variable. But the problem is that the string is ;-) "variable", How can I center the string in the middle? and if the string not match in a line of the paper...how can I resolve it? I'm not want to view on the screen the output...only print the result on paper. I'm using the print_open(), print_close(), etc command from the tutorial, but it tells nothing about this issue. Please, if someone know how to do it, help me! Thx in advance Alex