Print Operations
Media Sensing
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P1031442-001 ZP 450 User Guide 12/8/2010
Media Sensing
The printer has automatic media sensing capability. The printer is designed to continuously
check and adj ust media length sens ing for min or variatio ns. Once th e printer is printin g or
feeding media, t he printer continu ally checks and adjusts the medi a sensing to acco mmodate
for minor changes in media parameters from label to label on a roll and from roll to roll of
media. The printer will automatically initiate a media length calibration if the expected media
length or the lab el to label gap di stance has exceed ed the acceptabl e variation ran ge when
starting a print job or feeding media. The automatic media sensing in the G-Series printers
works the same for printer operations that use EPL and ZPL label formats and programming.
If the printer does not detect labels or black marks (or notches with blackline sensing) after
feeding the media the default maximum label length distance of 39 inches (1 meter), then the
printer will switch to continuous (receipt) media mode. The printer will keep these settings
until changed by software, programming or a manual calibration with different media.
Optionally, the printer can be set to do a short media calibration after printer power up or when
closing the printer with power on. The printer will then feed several labels while calibrating.
The printer’s media settings can be verified by printing a Printer Configuration label. See the
Printing a Test Label onpage14 for more details.
The maximum distan ce that the autom atic media type de tection and sensin g will check can be
reduced by using the ZP L Maximum Label Lengt h command ( ^ML). It is recommended that
this distance be set to no less than two times the longest label being printed. If the largest label
being printed was a 4 by 6 inch label, then the maximum label (media) length detection
distance can be re duced from the de fault distance of 39 inches down to 12 inches.
If the printer has difficulty automatically detecting the media type and auto-calibrating, see
Manual Calibration onpage52 to perform an extensive calibration. It includes a printed graph
of sensor ope ration for your media . This meth od disable s the prin ter’s automa tic media
sensing capability until the printer’s default parameters are reset to the factory defaults with
the four flash Feed button mode. S ee the Feed Button Modes onpage 56 for more details.
The automatic media calibration can be modified, turned on or turned off to meet your needs.
Sometimes print job conditions require that the printer use all the media on a roll. The two
automatic media conditions, power up with media loaded and closing the printer with power
on, can be controlled in dividually with the ZPL M edia Feed command, ^MF. The f eed action
discussed in the ZPL pr ogrammers guide for th e ^MF comman d is pri marily for au tomati c
media sensing and calibration. The automatic media calibration that controls the dynamic
media (label to label) calibration is the ^XS command. I f multiple m edia type s of differe nt
lengths, material or detection methods (web/gap, black mark, notches or continuous) are used,
you should not change these settings.
The media c alibration a nd detecti on process c an also be refined to match the media type
loaded into the printer. Use the ZPL Media Tracking command (^MN) to set the media type.
Sometimes the printer can detect preprinted media as the gap between labels or the liner
backing with print as a black marks. If the ^MN parameter for continuous media is set, then the
print does not preform the automatic calibration. The ^MN command also inclu des an
automatic calibration parameter (^MNA) to return the printer to its default setting to
automatically detect all media types.