Print Quality General Diagnostics; Print Quality Specifications - Xerox 8850 Service Manual

Print Quality General Diagnostics

It is important to understand the orientation of prints in order to troubleshoot image quality
problems. The following terms will be used when referring to prints made on the Printer:
1. Process direction is in the media feed direction.
2. Cross-process direction is in the side-to-side direction.
3. Defect isolation procedure.
Determining the distance between defects could help isolate problems to a specific compo-
nent. Defects that are 10.375 inches (265 mm) apart (lead edge of defect to lead edge of next
defect) in the process direction may be caused by the Drum. The circumference of the Drum is
10.375 inches (265 mm).
Defects that are 2.9 inches (75 mm) apart (lead edge of defect to lead edge of next defect) in
the process direction may be caused by the BTR.
Defects that are 7.075 inches (180 mm) apart (lead edge of defect to lead edge of next defect)
in the process direction may be caused by the Fuser Heat Roll.
8850/ 510DP

Print Quality Specifications

Test Patterns
There are nine internal test patterns that can be run from diagnostic mode [9-55]. (refer to Sec-
tion 6 for details)
Test Pattern 1 is used while adjusting lead edge. trail edge and side edge erase.
Test Pattern 2 is used to produce horizontal black and white horizontal/vertical bands and res-
olution targets.
Test Pattern 3 is used to produce ROGM image targets and 1.25" solid area squares that are
97.5 mm apart.
Test Pattern 4 is used to produce a 49 mm wide horizontal black band that is 450 mm from the
lead edge of the print.
Test Pattern 5 is used to produce solid area squares, ROGM image targets and a grid of thin
horizontal and vertical lines.
Test Pattern 6 is used to produce diagonally placed small ROGM targets.
Test Pattern 7 is used to produce diagonal horizontal and vertical lines that are 16.25 mm
apart.
Test Pattern 8 is used to produce solid blank vertical bands that are 93.5 mm wide.
Test Pattern 9 is used to produce various small ROGM patterns.
Solid Area Density (A)
This term refers to the image density of a totally black portion of the print.
(Figure 1) Use a wide roll of media and run test pattern
[9-55-5]. Select the black squares (A) and use the SIR 495.01 (PN 82P520) reference scale to
measure the density.
SPECIFICATION:
Media - All sites between 1.2 and 1.4 Solid Area Density (SAD)
Film - All sites equal to or greater than TBD
Solid Area Density (A) Uniformity
This term refers to the image density of a totally black portions of the same print.
(Figure 1) Use a wide roll of media and run test pattern
03/2003
Print Quality General Diagnostics, Print Quality
3-5
Print Quality