Xerox 4400DT Service Manual - Page 150

Image-Quality Troubleshooting Procedures The image-quality troubleshooting procedures that follow are meant to assist in correcting image-quality defects. These procedures provide defect samples, definitions and specifications to help identify the type of defect that exists, the test pattern to use, and actions required to correct the defects. Throughout these procedures, the term "vertical" refers to the process direction (the direction paper travels through the printer); the term "horizontal" refers to the scanning direction (the direction the laser beam scans across the page). Cleaning procedures should always be performed before beginning any Image-quality Repair procedure. Be sure that the paper meets printer specifications. Changing the paper, or using paper from a previously unopened ream, will resolve many print-quality issues. After resolving an image-quality problem, return to Image-Quality Checkout Procedures on page 3-41 to verify that no other image-quality defects exist. Index of Image-Quality Troubleshooting Procedures Light (Undertoned) Prints 3-54 Blank Prints 3-56 Black Prints 3-58 Vertical Deletions 3-59 Horizontal Deletions 3-61 Vertical Streaks 3-63 Horizontal Streaks 3-65 Spots 3-68 Unfused Image 3-69 Damaged Print 3-71 Resolution 3-72 Spot Deletions 3-73 Repeating Defects 3-74 Residual Image 3-75 Background 3-76 Uneven Density 3-78 Skewed Image 3-79 Registration 3-81 Skips / Smears 3-83 Phaser 4400 Laser Printer Service Manual 3-53