Printronix T4204 User Manual

Page 48

Chapter

Calibrating The Transmissive And Reflective Sensors

Due to manufacturing differences in transmissive and reflective label stock,
the sensors may have difficulty distinguishing between the label and the liner
(gap) or the label and the black mark. When this occurs, the printer will
display an error message on the LCD such as “GAP NOT DETECTED Check
Media” or “LOAD PAPER”. The printer’s sensitivity for detecting the TOF
(Top-Of-Form) position of the media installed can be optimized by using the
Calibrate features in the PRINTER CONTROL menu.

Sensor sensitivity can be improved by changing the Refl Value for reflective
media or by changing the Trans Value for transmissive media. These values
can be changed manually within the PRINTER CONTROL menu or can be
determined automatically by using the Run Calibrate procedure. The change
in values (derived automatically or manually) takes effect immediately within
the current configuration menu, but is not automatically saved. If Run
Calibrate is performed again the new values will overwrite the previous values
for the current menu.

The new values can be saved into non-volatile memory (menus 1-8 only) by
using the Save Configuration procedure. If the current menu in use is the
Factory menu, the values will take effect but cannot be saved into memory
and will be lost when the printer is powered off.

Use the Run Calibrate procedure to automatically determine the Trans or Refl
Values before attempting to change the values manually. When Run Calibrate
has completed successfully, the Sensed Distance option in the Calibrate
menu will display a distance in inches based on the media type in use:

•

transmissive media = the label length plus one gap length

•

reflective media = the distance from the trailing edge of one black
stripe to the trailing edge of the next black stripe.

The Sensed Distance value cannot be manually changed and is updated only
as a result of the Run Calibrate procedure. The factory default value of
Sensed Distance is 0.00 inches.

If Run Calibrate fails to determine the proper values and ends with a fault
message displayed (GAP NOT DETECTED or LOAD PAPER), you can try it
again by going back to Run Calibrate under the PRINTER CONTROL main
menu and then press the ENTER key. Or, you can manually change the
Trans Value or the Refl Value. Trans Value and Refl Value have a range of 0
- 20 (factory default = 10).

Once the correct values are determined and the Page Length setting in the
PRINTER CONTROL menu is equal to (or slightly less) than the physical
page length, depress the FEED key to advance media and determine if it
consistently stops at the correct TOF position each time.