iSys V12 Thermal Printer - Manual (Page 34)

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Adjusting the top of form sensor
1. Remove the two 6/32 x 2” philips pan head screws located at the top left and right corners of
the rear panel, swing the rear panel downwards for access to the main logic board (see Figure
7-2).
2. The TOF sensor needs to be set up so that it can properly detect the black TOF marks on
underside of fanfold paper. The sensor operates in the transition area where it is sensitive
enough to detect the marks on the paper, and yet will not detect the perforations of the paper.
3. To set up the sensor, insert fanfold paper into the plotter, orienting it so that a white portion of
the paper is over the sensor, close the lid to the plotter.
4. Turn the plotter on, press offline key, and scroll to the -FF length-menu selection. Press the
Up Arrow button until you obtain the sub-menu setting “Tof sens”. This setting enables the
plotter to advance the paper up to 18” while detecting for the TOF mark. Press the online button
to save the sub menu setting.
5. Press the offline key and scroll to the –Tst_none- menu selection. Press the Up Arrow button
twice to obtain the sub-menu setting “Tst_tofv”. Press the Enter button to enable this. This sub-
menu setting will allow you to view TOF voltage setting on the front display of the plotter which
will allow a user to set up the TOF sensor without using a voltmeter. The LED display will now
read between - 0.000 V – and - 5.000 V – due to the circuitry, the voltage displayed will be
either of the previous voltages, 0.000 or 5.000 Volts. Adjustments between the two will not be
displayed.
Using a potentiometer (pot) trimming tool, turn the pot located at R2 on the main logic board,
until the voltage displayed is -0.000 V-Adjust the potentiometer from -0.000 V-until a voltage of
approximately – 5.000 V-is displayed. This voltage is at the approximate transition point where
the sensor can detect between the media and TOF marks. Adjustments are made with the
potentiometer from this point to optimize the sensitivity to the marks. Adjust the potentiometer
two more full rotations in the same direction.
Press the Enter button to exit the TOF adjust mode. The LED display should show -Idle m1-.
6. Changing the plotter state to Offline, and pressing the Formfeed button will test the Top of
Form function. Manual form feeding will only work when the LED display reads - Offline
Observe the plotter as it advances the fanfold paper while detecting for the TOF mark. Once
the plotter stops form feeding, open the lid and check to see if a TOF mark has stopped over the
sensor location. If you find the plotter is stopping the paper short of a TOF mark, it may be an
indication the adjustment is too sensitive to marks on the media including perforations, and the
pot has to be readjusted. If the plotter advances the paper and stops past a black TOF mark,
this may mean it’s not sensitive enough to the marks and the pot has to be re-adjusted for this
as well. Returning to the - Tst_tofv – screen and displaying the TOF voltage may help to adjust
the sensitivity.
Increasing the voltage will give a corresponding decrease in the sensitivity of the sensor to the
marks, although this voltage will not be shown on the front display. This is done by turning the
pot further in the same direction as previously to change it from 0.000 volts to 5.000 volts.
Decreasing the voltage will give a corresponding increase in the sensitivity of the sensor to the