Just throwing some stuff out there ...
1. If it prints by sending a pdf file to the rip software, and then the rip software sends to the printer... check both the PDF (or whatever) settings and the rip software. Both the original program you´re sending out of and the final program you´re ripping with will have areas to look at.
2. Look everywhere for a shrink to fit, fit to paper size, or reduce oversized pages checkbox, and clear it out
3. look everywhere for a scaling option, and activate it, and set it to 100 percent
4. PDF gets its own settings box that is separate from (but works together with) the windows built in settings box. So go straight to start . settings . printers and find the windows advanced options for page size, choose postscript custom page size, and then specify the size exactly.
5. Watch for a popup dialogue or a checkbox that says automatically adjust paper size to margins or print size, or something that warns about portrait vs landscape printing. Basically tell it no, do not automatically adjust anything
6. This will produce offcenter printing rather than shrunken printing, but it pisses me off so I´ll mention it... beware of any option to tile oversized pages, uncheck it.
7. Lastly make sure there´s no crazy scaling option built into the printer itself, accessible via the printer´s control panel. Sounds unlikely but I am pretty sure a lot of printers support something like this.
So to recap... when you go to press ctrl+P you probably do a 2 stepper... printing using a standard dialogue box to a ripper, then going to the ripper and sending the job to the printer. As soon as you do ctrl+P there will be an options button (where scaling and tiling will hide) and a printer properties button (where portrait-landscape and some other stuff will hide). Then from there, there´s an advanced button with the standard windows printer options, the first of which is page size and which should be set to postscript custom page size. Also if you chose PDF as the printer, there´s a special set of PDF options, which I think is also accessed from ´properties´. Once you´re through all that you must dig through the rip software´s stuff. And never accept any offer to automatically adjust rotation or page size.
Very annoying but I know but the checkbox you need to clear out is in there somewhere.