Xerox DocuColor 12/DCCS50, Service Manual

Page: 1500 / 1617

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10-80 DocuColor 12/DCCS50
IIT/IPS Cooling, Image Processing (Digital Copier &
Reissue
Principles of Operation
IIT/IPS Cooling
The IIT drawer (including the carriages, lamp, lens and CCD array) includes no fan, since the
Xenon Lamp is much cooler than a quartz halogen Lamp. As shown in
Figure 1 , the IPS
drawer includes a small fan to remove heat from the PWBAs located there.
The circuitry for fan power and control is shown in Figure 3 .
Figure 1 IPS Fan Location
Image Processing (Digital Copier & Copier/Printer
Configurations)
Image Processing for copiers and copier/printers is divided into two groups of PWBAs. The
Pre-IPS PWBA, Memory System PWBA, Memory PWBAs and Post-IPS PWBA are only
included in these configurations and perform all image processing associated with image sens-
ing and scanning.
The remaining PWBAs in the image processing path are common to all machine configuration.
Of these, only the Halftone PWBA performs significant image processing.
All image processing PWBAs in all configurations are shown in Figure 1 , Figure 2 and Figure 3 .
Pre-IPS PWBA
The Pre-IPS PWBA accepts six line of analog color data from the CCD PWBA. These are in
the form of two sets of three color lines: Red, Green and Blue. The Pre-IPS PWBA contains the
Application Specific Integrated Circuits (ASICs) listed in
Table 1 , which also contains their func-
tions. Figure 1 shows the signal flow through the PWBA.
In addition, the Central Processing Unit (CPU) on the Pre-IPS PWBA accepts inputs from the
following sensors:
• Platen Sensor, indicating the presence of paper on the platen
IPS FAN
MOTOR/LAMP/FAN
DRIVE PWBA
Table 1 Pre-IPS PWBA ASICs and Their Functions
ASIC Name Functions
Analog Interface 1. Amplifies the analog signal
2. Offsets DC offset for varying analog AC signal
3. Multiplexes between two analog inputs for each color
Analog-to-Digital
Converter Converts analog input to digital value between 0 and 1023 (10 bit res-
olution)
IIC 1. Converts W-Reference
2. Corrects W-Level
3. Corrects shading using 7.5 kilobytes of RAM for each color
4. Corrects gap using a 7.5 kilobyte FIFO (First In First Out) chain
for each color
5. 1 X 5 Filter
6. Generates the CCD PWBA 9.97 MHz sample and shift clock.
SID 1. Senses original document size
2. Senses background color (ENL [Equivalent Neutral Lightness])
3. Senses original color (ACS [Automatic Color Sensing])
4. Corrects color (ACC [Automatic Color Correction])
TRE 1. Enlarges/reduces image in one direction, when enlargement/
reduction is requested by user
2. Rotates/repeats image, when requested by user
3. Creates mirror image, when requested by user
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