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Supply Sensing Systems 9820/9830/9835 Service Manual
July 1998 TC9830SM Rev. B 7/98 Confidential
39
meet, the threshold count is calculated as the sum of
half of the differential between the Low and Hi AD
counts captured plus the Low count. When a valid
BOF has been found it is saved and used as the
threshold for the TOF.
The next transition edge of importance is the TOF. It
is defined as the trailing edge of the feature. Once the
BOF has been found the software looks for a TOF. In
fact it uses the same AD threshold count calculated for
the BOF. The difference is that the TOF point is
determined as the AD count passes through the
threshold from the feature back to white.
The threshold value used for this first feature is not
saved in the averaging array because it only
represents the minimum span distance as defined by
the algorithm criteria. However, by the time the TOF
position is reached a full representation of the signal
profile has been captured and this actual profile is
what is used for BOF/TOF on the second feature.
When the second feature passes by the sensor the
valid BOT and TOF are those points that were
calculated from the first feature. The threshold points
calculated based on the signal profile captured from
this feature are saved as the second entry in the array.
For the third feature the threshold points become an
average of the first two features. Here after the array
is continually updated containing the last two threshold
values.
The calibration function is complete when the second
valid feature is found and measured. The existing
software has processed the physical aspects of the
label such as print length, feature length and TOF to
TOF distance into the tracking system. The software
can now track the label just seen by the sensor so that
it will be synchronized in correct position under the
printhead. Knowing label length provides the ability to
predict when the next feature can be expected.
Therefore, the only time the sensor will be enabled is
after calibration during the window of time when the
feature should pass by the sensor. The reason in
using a small window is to minimize detection of
extraneous pulses that may adversely affect the
accuracy of the algorithm.
MECHANICAL ADJUSTMENTS
This section describes:
• Bi-Cell Sensor Adjustment
• Print Contrast Adjustment
• Platen Motor Gear Adjustment
• Ribbon Tension Adjustment
NOTE: Field Service performs no electrical
adjustments.
Bi-Cell Sensor Adjustment
1. Turn Printer Off.
2. Load die-cut supply and turn off printer.
3. Connect laptop computer to printer’s serial port
(laptop must have SENDFILE V2.07 installed).
4. Set DIP switch 3 (bottom set) to ON (Diagnostics
Mode)
5. Set DIP switch 6 (bottom set) to OFF (Die Cut).
6. Turn printer on. Printer will feed two labels and
display 000.
7. Start SENDFILE (as follows).
8. Press M for Model number and press Enter.
9. Press Feed and Clear simultaneously on keypad
to access Diagnostics. SENDFILE will display
DIAG IDLE.
10. After SENDFILE displays IDLE, press D for
Diagnostics.
11. Remove Die Cut labels from the printer.
12. Check the emitter for operation, using an Infrared
Detector Probe.
13. Cover the Bi-Cell switch with a piece of black
electricians tape. Completely block all light.
DO NOT TOUCH THE SENSOR LENS WITH
YOUR FINGERS.
14. With all light blocked from Bi-Cell, note the
reading on SENDFILE. This is the reference
value for the sensor. Range is 2.35V to 2.55V. If
reading is out of range, replace Bi-Cell Sensor.
15. Remove electrical tape.
16. Place gray scale over sensor, glossy side down.
(HANDLE FILTER BY EDGES ONLY. SKIN
OILS CAN ALTER THE BI-CELL READING)
17. Close print module and note the Bi-Cell reading in
SENDFILE.
18. From back of Bi-Cell housing, turn adjusting
screw to obtain the reference value observed in
Step 14.
19. Open and close printhead carriage to verify
adjustment.