Hi,
I was looking at the image you attached that shows the light band, and I wanted to confirm the orientation of the image being printed to help trouble shoot the issue. When the printed page exits into the facedown tray, is the green band visible in the image at the leading or trailing edge of page? Also I was wondering if you had been able to print the PQ trouble shooting pages to help determine which color is not printing and causing the light band. I don't think your ITB is responsible for the band, but it may be related to the generation of the image on the cartridges by the laser scanner. If you can attach an image from the PQ trouble shooting pages that shows the band we may be able to get closer to finding the cause.
I work for HP
