Printer test for HP Photosmart printer 3210 all-in-one printer

My on-line photography assignment calls for me to do a RGB printer test by creating a scale from 0-255 placed next to a rectangle of RGB 0(black) and the white paper(rgb255). I have done this by using the layer window and merging the layers to represent a gray scale. My problem is the printer is not spitting out any image, only white paper? I tried printing a help page from photoshop(cs3) and this printed fine. I believe it has something to do with the way I either saved or created the file but I can’t seem to figure this out? Any help with this issue would be appreciated.