Is it possible that when a sheet is printed, that the background colors of the cells are printed as white instead of the colors they are designed to be?
If you go to page layout, on the last tab (sheet options) where you can set gridlines and rows/column to repeat, is a checkbox for printing Black and white. If the colors are subdued, I would think it would print them as white.
That is the only built-in support that I am aware of. Your printer may have its own options. You could look under properties when you do Print and the print dialog pops up.
in Excel 2003 and earlier, print settings is under the file menu.
in Excel 2007 and later, page layout is under the page layout tab. Got to the button that has gridlines and click on the sheet options at the bottom of the Button.
If none of those work, you might be able to kludge something together with conditional formatting if you are not using it anywhere else on your sheet. Something like if you put a 1 in a cell outside the print region, the conditional formatting would change all the backgrounds to white. You would need to conditionally format each cell in the print area. Again, in general, this is only if nothing else will work and you are not using conditional formatting already on your worksheet.
Does that help?