Xerox WorkCentre Pro 423 Service Manual page 253

3.3 Image Quality Troubleshooting
3.3.1 Copy Sample
When an image quality problem occurs, make A3 copy samples using Test Pattern
(499T247) in order to judge, understand the symptom and execute a suitable corrective
action. Use Test Pattern (499T281) for image quality problem of printout using the fax
send/receive features.
3.3.2 Cautions on image quality troubleshooting
Image quality problems are usually corrected according to procedures instructed in
troubleshooting tables corresponding to the problems. When an image quality problem
occurs continuously or an abnormal symptom is observed, check the installation
environment, originals used and lives of consumables.
1. Installation environment
The power source voltage must be 100±10%(FX), 110±10%(TFX)
220±10%(KX), 220 - 240V±10%(FXA) VAC.
l Avoid places subject to high temperature and moisture (near water valves, water
heaters, humidifiers, air-conditioners or fire sources).
l Avoid places subject to ammonia gas.
l Select places not subject to direct sunshine (if unavoidable, instruct the customer to
install curtains).
l Select places with good ventilation.
l Select places where the machine can be secured horizontally level.
2. Check of originals causing image quality problems
l Check of original density
•
E.g.: Check for wrong judgment of high background when diazo copies or
newspapers are used as originals.
•
E.g.: Check for wrong judgment of too light copies when light pencil written or
blue no-carbon paper originals are used.
3. Check of consumables
l Check lives of CRU: 24K copies
4. Check of paper
l Store paper at a place of low humidity.
5. Host-side check for an image quality fault
l Check whether the fault depends on the application.
l Try printing from another client.
l Try printing by another application.
WorkCentre Pro 423/428
l Try printing by another icon (file).
l Replace the application.
l Check the client system.
l Try printing by another icon (file).
3.3.3 Basic rules on action against image quality problems
The first thing to be done is cleaning of components.
Check for the mirror, lens, ROS window, platen glass, platen cushion, white reference
board, transport section, and fuser section for contamination and clean, if necessary.
Excessive or quick contamination at certain components is often caused by improper
environmental condition. In such a case, a suitable action should be taken.
3.3.4 Image Quality Adjustment
Proper adjustment has been completed to the machine on delivery and no further
adjustment should be necessary in the field. However, extra adjustments can be required
according to the customer's preference.
When light copies, high background or too dark density is generated, perform
troubleshooting by referring to 3.3.5 Corrective action against image quality problems.
When the problem persists, perform adjustment.
1. Diagnostic Code used for Image Quality Adjustment
Use Diag Code [21-5] to [21-57] to perform image quality adjustment.
2. Cautions on image quality adjustment
Check notes described by symptoms below when performing image quality adjustment.
1) For improving reproducibility of low concentration images as required by the customer
(Green or blue characters or lines)
Instruct the customer that density can normally be improved by manually selecting the
"Dark" button. When the setup data is changed as described below, confirm with the
customer that the change may trigger other problems.
l Decreasing the Diag Code [21-31] setup data.
Note In this case, threshold level for eliminating the AE ground color decreases and as
a result, high background of the originals, such as newspapers, may appear on
copies. Recommend the customer to use the manual density adjustment button.
3-9 CHAPTER 3 IMAGE QUALITY TROUBLESHOOTING
3.3 Image Quality Troubleshooting