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October 9th, 1995
During power-up initialization, the scanner performs the following steps (refer
to the flow chart on the previous page).
1. Checks the ROM checksum and makes a RAM read/write check.
2. Presets the main scan timing of the SIP3 (gate array for image
processing), and initializes the SCSI controller and the SBC (Scan Buffer
Controller).
3. Checks the ADF exposure cover switch signal. If the CPU detects that the
cover is open, an ADF exposure cover open error occurs.
4. Sets the main scan timing to the default, and loads the gamma, dither,
and error diffusion patterns into the SIP3.
5. Turns the xenon lamp on.
6. Adjusts the difference between the even and odd black levels by
controlling the output level of channel 1 of the D/A converter. Adjusts the
black level by controlling the output of channel 2 of the D/A converter. If
the CPU cannot adjust them to the specified levels, the CPU determines
that a shading error has occurred.
7. Initializes the scanner motor driver.
8. Checks the home position sensor signal timing while moving the
carriages. If the CPU does not detect a signal change within the specified
period, it determines that a home position error has occurred.
9. Checks the peak level of the auto gain control of the SIP3. If this value is
below the specified value, the CPU determines that a lamp error has
occurred.
10. Checks the minimum level of the white plate image data. If this value is
below the specified value, the CPU determines that a shading error has
occurred.
11. Looks for the origin mark within the specified area. If the CPU does not
detect the origin mark, it determines that an origin positioning error has
occurred.
12. Initializes channel 4 of the D/A converter. If the CPU fails to do this, it
determines that a shading error has occurred.
13. If a shading error, lamp failure, or origin positioning error is detected
during the above initialization process, the scanner retries the
initialization up to three times. If the CPU detects an error at the third time
(step 18), the CPU indicates a system error.
14. Checks the platen cover interlock switch signal. If the CPU detects that
the switch is open, it determines that an ADF open error has occurred.
DETAILED SECTION DESCRIPTIONS
2-3
INITIALIZATION
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