User`s guide

Label Requirements
PREPRINTED LABELS
To ensure trouble free operation of the printer gap sensor, and to achieve normal print head life, no
pre printing should be placed on the label in the gap sensor path or in areas which will be printed
by the scale printer. However, since preprinting is commonly used by many customers the following
guidelines must be followed.
1. Inks used for preprinting must be specially formulated for use in thermal printers. If proper
inks are not used they can adhere to the print head. This ink build up on the print head will
interfere with heat transfer from the print head to the paper and cause printing elements to
burn out. Another problem with inks not formulated for thermal printing is that they can
contain chemicals which will cause the glass overcoat to chip off of the print head, causing
failure to print in the chipped areas.
2. If black ink is used in preprinting in the gap sensor path shown below, a dense black stripe
will have to be printed on the back of the liner, as shown below, to prevent the gap sensor
from being affected by the black preprinting. (Colors other than black might also be a
problem and should be tested by the customer) The black stripe must have gaps which
correspond to the label gaps. The black stripe on the liner must have a minimum
transmission optical density of 2.3 and must be uniform. In addition, the gap sensor circuit
will need to be adjusted for operation with the black stripe as explained in the product
service manual. This adjustment will need to be checked any time label paper is changed,
for example when labels are procured from a new supplier.
3. If an optical density of at least 2.3 cannot be achieved in the black stripe on the back of the
liner, the sensor path in the center of the label must be free of black preprinting.
UC-ST User’s Guide
5-7
BLACK STRIPE
GAP SENSOR PATH