Konica Minolta bizhub C658 Service Manual page 1800

bizhub C658/C558/C458/C368/C308/C258
3.3.8 Skew adjustment/skew adjustment reset
• There are cases where the "color skew correction control" cannot be executed for some reason. The machine provides functions that allow
you to reset the "skew adjustment data" against these situations.
• For details of the Service Mode, see "
(1) Possible conditions and causes
• The PH unit has been replaced with a new one.
• The alarm code "P-14: skew correction trouble" is displayed.
• A door is opened or the main power switch is turned OFF during color skew correction control, causing the skew correction sequence to
be halted; as a result, the current position of the skew correction motor is unknown.
• The backup position information of the skew adjustment motor settings in the machine is lost operations such as replacement of the
eMMC board.
3.3.9 PH unit temperature detection control
• The temperature inside the PH unit is measured at intervals of 30 sec. by the PH temperature sensor mounted in the PH unit.
• The detected temperature data is recorded to form part of the environmental information data and used for controlling, for example, color
registration, 1st transfer output determination, and transfer roller cleaning.
3.3.10 PH window cleaning
• The PH window, if contaminated, blocks the path of the laser beam and the surface of the photo conductor can no longer be exposed
properly. This could result in image problems, including white bands or white lines on the print image.
• The PH window is provided with a cleaning guide that prevents any image problem caused by a dirty PH window from occurring.
The following illustration is for bizhub C368/C308/C258.
[1]
[1] PH window cleaning tool
(1) PH window cleaning procedures
• Slowly pull to the front the PH window cleaning tool and push it back into the original position. This allows the cleaning material mounted
on the PH window cleaning tool to remove any foreign matter from the surface of the PH window.
• The machine is not equipped with any mechanism that automatically cleans the PH window. This makes it necessary to clean the PH
window manually at regular intervals.
(2) PH window cleaning timing
• Clean the PH window of each color when the drum unit/K is replaced with a new one.
3.3.11 Image processing
The following image processing procedures relating to the write section are available. For details, see "
block diagram".
(1) Write section image processing block diagram
• Resolution conversion processing in the main scanning direction/movement processing
• Resolution conversion processing in the sub scanning direction
• Main scanning position correction Speed conversion Modulation
O THEORY OF OPERATION bizhub C658/C558/C458/C368/C308/C258 > 3. WRITE
I.5.4.9 Print Head Skew Adj.".
O-25
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O.18.2 Write section image processing
SECTION (PH SECTION)