Calibrating Preprinted Labels on a 105SL Printer
In some situations the 10SL may have difficulty calibrating preprinted labels. The printer will exhibit this by not lining the gap between labels at the correct tear off point on the tear bar consistently or may even display a false paper out condition.
If at all possible align the upper and lower sensors so they track over a portion of the label where there is no preprint or minimal preprint as shown below.
upper web sensor
lower web sensor
In some applications where a variety of preprinted labels are used the best approach is to set the sensors in a location where the least amount of preprint may occur across the the selection of labels you are dealing with. You maybe limited with some preprinted labels because there is no way to position the sensors to avoid the preprinted sections.
If you are at a point regardless of where the sensors are positioned the printer is not able to calibrate then making some additional manual adjustments may become necessary.
The first step is to print a sensor
The following information explains in detail how to read a profile to get a better understanding of how the sensors work.
Sensor Profile Information
A media sensor profile is a graphical representation or the sensor's view of the label. The profile can tell you if the printer sensor sensitivity is correctly adjusted as well as if the sensor is seeing the label gap, hole or notch correctly.
In the profile shown above you can tell the following:
"A" is the MEDIA S value and in the above example is set to 75. This is the value (a trip point) at which the printer will detect it is out of media. If the "C" and "D" values go above the MEDIA line for more than 1/2" of travel the printer will go into a PAPER OUT condition. ( i.e. a "C" peak can exceed the MEDIA value but not "C" plus "D" for 1/2".)
"B" is the WEB S value and in the above example is set to approximately 50. This is the value (a trip point) that determines the leading edge of the label. Each time the peak passes the WEB value the printer identifies the top of form. This value should be in an area where any "noise" or variations in "D" do not come close to passing the WEB line but not so high that the "C" peak fails to cross.
"C" is the peak produced by the sensor viewing a label gap, hole or notch. As the gap passes the sensor more light is passing to the upper sensor which results in the peak as shown above. As the peak passes the WEB line the printer identifies the top of form. This peak should have a consistent appearance and distinctly protrude from the background "D".
"D" is the background produced by the sensor light shining
through the liner and label. This may vary in height from barely visible (using
card stock or other light obstructing material) or up to 20 to 30 as in the
example shown above. If the "D" value appear too high try lowering the
"MEDIA LED" value in the LCD Display. If it is already at 000 you can
try moving the lower sensor slightly to misalign the light path.
In the example below you can see how the "D" background is exceeding the "B" Web S value. Preprint on the labels can cause the profile to have noise along the background. The "D" background and the accompanying noise spikes need to be reduced to a level that stays consistently below the "B" Web S value. Otherwise the printer will not be able to distinguish the true "C" peak from the noise and excessive background levels.
The way to clean up the profile on the preprinted label is to disable the
auto-calibrating feature which is part of the 105SL default settings.
To do so start by:
You'll notice the top of the pulse falls nicely between the established "B" web and "A" media sensor lines. Also the noise as well as the rest of the "D" background stays below the "B" web line.
Once you've gotten to this point its likely that any preprinted labels you have should be able to calibrate properly. If not print a profile on the problem label and see if some tweaking to the sensor values helps.