This is a printer driver issue, usually with the HP 2100 or HP4550 laser printers. Some HP print drivers are not able to clip the output to the limits of the card because they do not support rectangular clipping. This is what causes the black boxes.
We suggest downloading the PCL 5e driver as an alternative printer driver (especially for the HP 2100’s). Here are a couple of links to the 2100 and 4550 laser printer drivers:
If you have a different model of the Laser Jet printer, you may need to search HP's website for the PCL 5e drivers, or contact their technical support for the location of those drivers.