HP Deskjet 6540 Color Inkjet Printer - Manual (Page 146)

Streaks appear in a light portion of a printout
Try the following:
• Install a photo print cartridge in the printer.
• Rotate the image 180 degrees.
Image is printed at an angle
Follow these steps if the image is printed at an angle:
1. Remove all paper from the In tray.
2. Load the photo paper correctly in the In tray.
3. Verify that the paper guides fit firmly against the media.
4. Follow loading instructions for the media type.
HP Deskjet 6500 series printers User's Guide
146