Diagnostic aids 3-397. Print the Quick Test page again and check that the darkest line in the center graph is equal to zero. If it is,then check to see if the left, top, and bottom margins are detected. If it is not, then repeat step 5.Note: The alignment of the left margin positions the black plane to the right or left. The alignment of the rightmargin does not alter the margins and should only be used to adjust the printhead.Printhead assembly mechanical adjustmentA printhead needs to be correctly positioned after it has been removed. Use a pencil to mark the screw locationsof the old printhead on the metal frame. Align the new printhead relative to the location of the old printhead.Note: Skew is caused by a sheet being fed through the printer while misaligned. The entire image is rotatedrelative to the sheet edges. However, a mechanically misaligned printhead causes the horizontal lines to appearskewed, while the vertical lines remain parallel to the vertical edges. There are no adjustments for skew. Checkthe pick roll (paper pick assembly) for wear, the paper path for obstructions, the fuser for proper setting, and thetray paper guides for fit to the media.To adjust the printhead:1. Enter the Diagnostics Menu. See “Entering Diagnostics menu” on page 3-17.2. Select PRINT TESTS.3. Select Tray 1.4. Select Single.5. Fold the printed test page on the left side so that a few millimeters of grid lines wrap around the outside ofthe fold. See photo below.6. Fold a second vertical fold near the center so that the left side top edge aligns with the right side top edge.PrintheadmisalignmentPaper feedskew
