Printer User Manual

Print Operations

Media Sensing

8/4/10 GX420d™ / GX430d™ User Guide 980611-001 Rev. C

Media Sensing

The G-Series™ printer has automatic media sensing capability. The printer is designed to

continuously check and adjust media length sensing for minor variations. Once the printer is

printing or feeding media, the printer continually checks and adjusts the media sensing to

accommodate 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 label to label gap distance has exceeded the acceptable variation

range 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 (Printer Configuration) Label on page 19 for more details.

The maximum distance that the automatic media type detection and sensing will check can be

reduced by using the ZPL Maximum Label Length 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 reduced from the default distance of 39 inches down to 12 inches.

If the printer has difficulty automatically detecting the media type and auto-calibrating, see

Manual Calibration on page 92 to perform an extensive calibration. It includes a printed graph

of sensor operation for your media. This method disables the printer’s automatic media

sensing capability until the printer’s default parameters are reset to the factory defaults with

the four flash Feed button mode. See the Feed Button Modes on page 96 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 individually with the ZPL Media Feed command, ^MF. The feed action

discussed in the ZPL programmers guide for the ^MF command is primarily for automatic

media sensing and calibration. The automatic media calibration that controls the dynamic

media (label to label) calibration is the ^XS command. If multiple media types of different

lengths, material or detection methods (web/gap, black mark, notches or continuous) are used,

you should not change these settings.

The media calibration and detection process can 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 includes an

automatic calibration parameter (^MNA) to return the printer to its default setting to

automatically detect all media types.