Xerox WorkCentre Pro 423 Service Manual page 251

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Output Unit and Image Flow of Built-in Test Pattern
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WorkCentre Pro 423/428
ROS Unit
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Using Built-in Test Patterns
Built-in Test Pattern is used for identifying the problem cause whether it is in the Xero
related IOT or IIT, apart from analyzing boards on image quality problems caused by
control boards. Following is the Test Patterns used for analyzing image quality
problems and problem identifying method:
Image Quality
Test Pattern
Problem
Too light copies Continuous
gradation [23-21]
l Grid (1Bit)
Poor
reproducibility of [23-6]
l Continuous
concentration
images gradation
[23-21]
l White Off
High-Background
[23-10]
l Continuous
gradation
[23-21]
l White Off
Defects
(White paper/Solid [23-10]
l Solid black
black, White/Black
bands) [23-11]
3-7 CHAPTER 3 IMAGE QUALITY TROUBLESHOOTING
How to identify the problem area
Check that two black bands copied with the
darkest density of the Test Pattern copy has
almost the same density as 1.3 solid. When it is
lower, the problem control board is in the IOT
side, when it is the same, on the IIT side. Perform
an appropriate troubleshooting by referring to
3.3.5 Corrective action against image quality
problems.
When the problem is not reproduced by using the
Test Pattern specified at the left column, the
problem can be in the IOT side, when it is
reproduced, it can be in the IIT (density related
setup data).
Note ROS Power Set Up and density
related data setup are properly
adjusted on delivery. Refer to 3.3.4
Image Quality Adjustment, and be
careful on changing setup values.
Use the Test Pattern specified at the left column
and check if the background covers the entire
copy. When the entire image has background, the
problem control board can be on the IOT side,
when it has not, the IIT side.
Perform an appropriate troubleshooting by
referring to 3.3.5 Corrective action against image
quality problems.
When the defect is generated to the specific Test
Pattern, the IOT control board may have the
problem, and when it is not, the IIT board may
have the problem. Perform an appropriate
troubleshooting by referring to 3.3.5 Corrective
action against image quality problems.
3.2 Image Quality Specifications