Perhaps installing the latest printer driver for the deskjet will cure it.

Jarm wrote:

I used the Microsoft info to add a "mimic watermark" in Excel 2003 (I used a
jpeg because I wanted to show my company logo greyed out in the background).
The watermark prints perfectly on a Laser printer but prints as a black box
on a deskjet (even though it looks perfect in the print preview screen). I
am certain that I have the correct printer driver. Has anyone seen this
before? Does anyone know why it is doing it?