IBM 4247-003 Maintenance Manual - Page 148

Print Quality Failures (Darkness, Location, Quality) Action Vertical print line misalignment (lines move upward, page-to-page). 1. Install a new upper feed roller. 2. Install the latest level paper bail assembly with the improved spring arrangement. The latest level paper bail has 2 blue tabs on the left end cap; the older has 1 tab. Vertical print line misalignment. [Lines move downward on the rear path as much as 1mm (0.039 in.) following the first page after initial load.] 1. Check the operation of the pinch rollers. 2. The rear forms path is not the same as the front forms path. Rear path registration is affected by the 180 degree turn the path makes around the platen. On the front path, paper passes straight through the printer. Print line registration on the rear path can change by up to 1mm after the initial load. This small change in registration might be objectionable to a customer using pre-printed forms if characters print outside of a box. The solution is to raise the print 1mm higher on the first page by raising the load position. This will keep the print inside the box on all pages. Registration-critical jobs, where a small change is not acceptable, should be run on the front path. Fanfold paper print line skew. Print line too high or low at one end of line. See "Paper Path Service Checks" on page 301. Single sheet feed print line skew. Print line too high or low at one See "Manual Sheet Feed Path Check" on page 317. end of line. Chapter 1. Diagnosing Problems 148