I believe that SketchUp exports images at the resolution of your monitor, say 72 or 96 dpi (dots per inch). You printer setting may be, say 300 dpi. So the print will be 96/300, or .32 times smaller then what you see on the screen. SketchUp was never designed to export or print scaled drawings. I think it is possible to match a exported image to a printer, but you have to calculate the print (not paper) size in dpi, then export the image at (in my case) 300/96=3.125 times the SketchUp window size. Say my SketchUp display is 1100x900 dpi (you can get this with the print functions), then I must export the image at 1100X3.125 by 900X3.125. SketchUp has some export limits I do not recall off hand.
If all you want to do is print from SketchUp a image as large as you can on your printer, set the printer properties to "scale to fit". This will typically be a low resolution image. To get around that, export a large image to a file, open the file with the default viewer, and print "scale to fit".
In any case, always print with a preview, that way you can see if the result is what you want.