HP Designjet T2500 eMultifunction Printer series - Manual (Page 224)

4. If the problem persists, analyze pattern number 7 in modules A through E of the diagnostic plot. A
correct example is given below, followed by two incorrect examples. Note that there is a black ring near
the center of pattern 7. In this step, you must look at the region near the black ring. If you can see
discontinuities in the black and white lines, call HP support and report a “defocus or blurring” error.
Incorrect paper advance, skew during scanning, or horizontal
wrinkles
You may encounter problems with some thick glossy originals being moved through the scanner’s paper
path. In some cases, the original may become skewed during the scanning process.
If some of the paper rollers are not working correctly, you may find small horizontal wrinkles in the scanned
image, due to the paper being stuck in some regions while not in others.
214 Chapter 23 Troubleshooting scan-quality issues ENWW