1. C9600/C9800 Auto Paper Thickness Detection
Naohide Hayashi
European Technical Support Centre
25/March/2005
European Technical Support

2. Sensitivity Adjustment
Contents
Mechanism
Specification
Sensitivity Adjustment

3. Auto Paper Thickness Detection – Old C9xxx
Paper Thickness Sensor
Feeding Direction

4. Auto Paper Thickness Detection – C96/9800
Paper Thickness Sensor
Paper direction
Screw for adjustment
New paper thickness detection mechanism introduced.
The sensor behaves like a variable capacitor.
The thickness of the paper changes the capacitance.
The output frequency is changed accordingly.

5. Spec – Auto Paper Thickness Detection
Tolerance within ± 10 µm (for the paper thickness up to 150 µm) within ± 15 µm (for the paper thickness greater than 150 µm)
It carries out (same as C9300/9500):
Before printing the 1st sheet from each tray after POW-ON
Before printing the 1st sheet from the tray that was open and closed (paper may have be changed) .
After fuser cleaning process
Before printing the next sheet when the 1st sheet was detected as “Ultra Heavy” (see the next slide)
Before printing the 1st sheet from MP tray when the printer detects that paper is supplied on the MP tray.
If JAM occurs when the auto paper thickness detection is supposed to be carried out, it carries out again after the jam recovery.

6. “Ultra Heavy” or “Special Heavy”??
The detection tolerance for thicker paper is not good (esp. “Ultra Heavy” or “Special Heavy”).
For confidence, detection is carried out 2 or 3 times to identify.
Boarder between different thickness
Algorithm to decide “Heavy” or “Ultra Heavy”
A: The detection result is “Ultra Heavy”
B: The detection result is “Heavy” but only 5 µm smaller than the boarder
C: The detection result is “Heavy”
If the detection result for the 1st sheet is A and B or A for the 2nd sheet, the printer decides the media is “Ultra Heavy”.
If the detection result for the 1st sheet is A and C for the 2nd sheet, another detection is carried out for the 3rd sheet:
If the result for the 3rd sheet is B or A, the printer decides the media is “Ultra Heavy”, otherwise “Heavy”.
Algorithm to decide “Heavy”, “Ultra Heavy”, or “Special Heavy”
A: The detection result is “Special Heavy”
B: The detection result is “Ultra Heavy”
C: The detection result is “Heavy” but only 5 µm smaller than the boarder
D: The detection result is “Heavy”
If the detection result for both the 1st and the 2nd sheet is A, the printer decides the media is “Special Heavy”.
If the detection result for the 1st sheet is A and B for the 2nd sheet, the printer decides the media is “Ultra Heavy”.
If the result for the 3rd sheet is D, the printer decides the media is “Heavy”.
If the result for the 3rd sheet is B, the printer decides the media is “Ultra Heavy”.
Algorithm to decide “Heavy” or “Ultra Heavy”
Algorithm to decide “Heavy”, “Ultra Heavy” ,or “Special Heavy”

7. Messages on LCD Panel – Auto Paper Thickness Detection
Details
THICKNESS ADJUSTING
When thickness detection is carried out.
THICKNESS NON-PAPER FRQ ERROR
Frequency value is outside of the standard error (no media)
THICKNESS PAPER THICKNESS ERROR
Media thickness is outside of the valid range (app. 500µm)
THICKNESS SNS FRQ ERROR
Sensor output is outside of the valid range (no media)
THICKNESS THICK_PAPER ERROR
A sheet that has 100µm or less thickness is detected after deciding "Ultra Heavy”
500 µm ≈ 5 sheets of 24lb paper

8. Sensitivity calibration – Auto Paper Thickness Detection
Adjustment is required when:
Paper thickness sensor is replaced
The resist roller is replaced
The PU (engine) PCB is replaced
How?
Step 1. Zero point adjustment
Step 2. Tolerance adjustment

9. Zero point adjustment – Auto Paper Thickness Detection
To Adjust the sensor output when no detection is carried out.
Procedure
Enter the diagnostics mode.
Press [] until “SWITCH SCAN” is displayed, and press [Enter].
Press [] until “REG L/R_DENS_WEIGHT” is displayed, and press [Enter].
4 Hexadecimal numbers are displayed. See the 4th number. xxx, xxx, xxx, xxx
Adjust the 4th number around 0x12C (possible range:0xFA ~ 0x15E) by rotating a screw.
Press [Back] and exit [System Maintenance Mode].
How to enter the diagnostic mode?? 1) POWON+[MENJ]+[MENU]+[HELP] 2) Press [MENJ] or [MENU] until “DIAGNOSTIC MODE” is displayed, and select [Enter].

10. Tolerance adjustment – Auto Paper Thickness Detection
Carry out the tolerance adjustment after the zero point adjustment.
This adjustment is carried out with the maintenance utility.
Media to be used. 4 pcs of Transparency sheet ( )
Thickness of 4 pcs of media should be measured in advance (by MDQ-30M, MDQ-30).
Details are mentioned in the maintenance manual