Choosing
the Right Materials & Print Accessories
There are a number of variables involved in
printing labels with thermal and thermal transfer
printers. With careful consideration of your
application, you can choose the right materials
to work with your printer to guarantee optimal
printer performance and consistent print quality.
The key
to specifying the correct media, similar to
the correct printer, involves a solid understanding
of the application. Zebra recommends analyzing
the following label supplies related issues
in conjunction with your thermal printer selection:
Desired
Print Technology
Dependent on whether direct thermal or
thermal transfer print technology is
chosen to satisfy your application requirement,
the selection and types of label material utilized
will vary accordingly. For optimum printer performance
and the extended life of your print-head mechanism
and/or label, it is important to select the
right media and ribbon (in the case of thermal
transfer printing) to perform with your printer
and within the constraints of your application.
Choosing the wrong media can result in poor
print quality, printer malfunction and/or frequent
print-head replacement. Your local reseller and/or
Zebra Supplies Specialist can assist
you in choosing the right thermal materials
to operate with your Zebra printer.
Media
Type
Thermal printers are designed to operate with
a variety of media types, including pressure
sensitive, die-cut, butt cut, perforated, notched,
hole-punched, continuous, tag or ticket
stock labels. The diagrams below highlight
some of the most popular label varieties used:
The
type of media sensors the printer has dictates
its ability to operate with certain media types.
Unless the media is continuous, die cuts, black
marks, or notches help the printer determine
the top of the label. Zebra printers come equipped
with a variety of media sensors that enable
the printer to gauge vertical label length during
the media calibration process.
Calibration
is a process that a printer performs in order
to gauge the length of the label material loaded
within it. Sensors within the printer’s
media compartment – commonly located around
the print-head - detect either the white spaces
(inter-label gaps) or black marks and/or notches
on the reverse side of the label stock that
represent a label’s actual face size (length).
Printer calibration ensures that one’s
data is aligned and prints correctly on the
label stock.
Zebra
printers can be configured to contain any one
of the below sensor varieties:
Transmissive
Media Sensor – is used to gauge label
length for media with visible interlabel gaps,
notches or pre-punched holes. Light from the
sensor passes through the gaps in the label
materials semi-transparent backing enabling
the printer to measure label length during calibration.
Reflective Media Sensor –similarly,
a reflective sensor emits light which is
reflected back to the sensor when it reaches
a black mark appearing on the reverse side of
the label stock. Such specialized media is commonly
referred to as black mark media.
Dual Media Sensors – two sensors within
the printer (one reflective and one transmissive)
that have the ability to detect both
interlabel gap and black mark media, irrespectively.
Zebra Xi Series printers come equipped with
dual media sensors.
Multi-functional Sensor – refers
to a single sensor within the printer that has
the ability to detect both interlabel
gap and black mark media, irrespectively. Zebra
Z-Series printers come equipped with multi-functional
sensors.
Application Surface
Application surface is another important factor
to consider when selecting the right media to
operate within the constraints of your application.
Application surface refers to the type of surface
upon which the label will be applied. Surface
features can be flat, smooth, curved, rough,
rigid, flexible, clean or contaminated
(dust, oil, powder, etc). Certain media types
may be better suited to deal with certain application
surface criteria than others.
Adhesive Type
Adhesive type refers to the label’s level
or degree of adhesiveness. Generally speaking,
there are two types of adhesives, acrylic
and rubberized. A rubberized adhesive
label is a pressure-sensitive adhesive based
on natural or synthetic rubber. Rubber based
adhesives offer good general purpose performance
and may be used on a wide variety of surfaces
and temperature ranges. They can be used on
most packaging materials, including plastic,
glass and metal. Rubber based adhesives provide
excellent adhesion to corrugated materials.
Most importantly, rubber based adhesives have
a high initial tack. Meaning they stick
immediately to a surface which makes them particularly
useful on curved or irregularly shaped surfaces. An
acrylic adhesive label is pressure-sensitive
adhesive based on high strength, acrylic polymers.
Unlike rubber based adhesives, acrylics require
a short period of time to set (a minimum of
24 hours). Once they are set, they provide
superior permanence and durability. Acrylics
are extremely strong and resistant to environmental
conditions which make them suitable for heavy
duty applications.
In
addition, some label media varieties come equipped
with a permanent adhesive while others
are removable enabling them to be lifted
off and re-adhered again elsewhere. Still others
are recyclable, freezer-grade, patterned
or tamper evident:
Freezer-grade
labels are designed to be applied in an extreme
cold (-20F) environment. Freezer-grade materials
can be applied at much lower temperatures than
other adhesives.
Patterned
labels are labels that have adhesive on
a portion of the label with another portion
of that same label having no adhesive. Jewelry
tag labels are a perfect example of this label
type. The two ends of the jewelry tag have a
permanent adhesive while the middle part has
no adhesive so as not to stick to the jewelry
item itself.
Tamper
evident labels have acrylic adhesive whereby
a pigmented adhesive is used to leave the word
"VOID" behind on the product if the
label is removed. Such labels are ideal for
labeling physical assets where security is essential.
Application
Temperature
Application temperature refers to the minimum
or maximum temperature present at the time the
label is to be applied to the item or product
in question. Application temperature is important
in that some adhesive materials are better suited
to deal with extremes in heat and / or cold.
A label that is not suitable to the application
temperature it is subjected to may not stick
properly. Thus, defeating the whole purpose
of bar coding as a means of automating certain
functions or processes.
Service
Temperature
Service temperature differs from application
temperature in that it specifically refers to
the temperature range that the label must withstand
throughout its useful life. Zebra’s Supplies
Selector Guide is a helpful reference tool
that can be used in order to gauge the application
and service temperatures for our various media
types.
Exposure
Exposure refers to the type of environmental
conditions and/or stresses that the label or
tag must withstand. Common stresses found in
labeling applications to take into consideration
when choosing a media type include moisture/humidity,
chemicals, abrasion, sunlight, heat, cold, blood
etc. Any such factor when coupled with the
wrong media type that is not designed to withstand
such stress can result in poor print quality,
printer jams or fading.
Method of Reading the Label
The method of reading a label can differ depending
on the application. The two most common methods
of reading a bar code label are through the
use of (1) scanners that interpret information
when linked to an external computer database,
or (2) human readable symbologies that
are visible and can be read easily with the
human eye. Human readable information runs the
risk of being misread by a worker which can
sometimes cause errors. Infrared scanners, though
a reliable form of data capture and transmission,
operate best when used within certain distance
ranges. When purchasing a scanning product,
it is important to make sure that the scanner
can perform within the distance range you need
it to. Scanner manufacturer’s do specify
the distance read capability of their product
on their specification sheets.
Method of Application
Method of application refers to the manner
in which the label is to be applied. Label application
can be accomplished, primarily, in one of two
ways – e.g. by hand or by utilizing
a label applicator system. Hand application
is the more economical approach, yet it is not
as expedient compared to that of an applicator
system. Applicator systems are frequently accomplished
utilizing pneumatic cylinders. A conveyor or
pneumatic cylinder system can align and position
a product toward a labeling station where a
pneumatically driven applicator arm then adheres
a peeled label to the side of the product. Such
applicator systems can be either simple or complex
in nature which naturally require a larger budget
to accomplish.
Re-Cyclability Factor
For some applications, recyclable label material
may be preferred. Linerless label stock is a
perfect example of how an ecological concern
for the environment resulted in the production
of more environmentally friendly label materials.
Linerless label media, as its name suggests,
utilizes no liner backing. It commonly consists
of continuous media with no perforations. Its
top surface can be printed on, whereby its reverse
side contains a light adhesive. Thus, foregoing
the need for the liner altogether. Linerless
label materials are particularly popular in
many European countries. In light of this trend,
Zebra/Eltron offers a number of printer models
that have this specific print capability.
Budget
Whether choosing a printer or labeling supplies,
one’s budget for spending plays a critical
part in the product selection process. It is
essential not to overlook the cost of labeling
supplies in reviewing one’s application.
In all actuality, the label itself should always
be your first area of concern. From its
size, content, industry compliance and material
type, to the selection of the appropriate printer
to print that label with - one’s entire
labeling application revolves around the label.
One’s budget concessions, therefore, must
effectively take both areas of label supplies
and printer selection into account.
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