19
In applications where the web material is too narrow for both bearer rings to contact the surface of the web,
contact with one bearer ring is acceptable. When the web is too narrow for even one bearer ring to contact the
web and still position the print as necessary, a custom made guide roller can often be utilized.
SPECIAL WEB PRINTING APPLICATIONS
PRINTING ON NARROW WEB MATERIALS
Using this approach, the guide roll must be machined with a
groove which will not only accurately guide the web material
and drive the guide roll but it must also keep the surface of
the web material flush with the surface of the guide roll
where the bearer rings make contact. (See Figure 30.)
This method of mounting is generally more appropriate when
the web material is extruded rubber or some similar mate-
rial which has a high coefficient of friction since it must drive
both the guide roll and the print drum. Using a custom guide
roller which is driven by an external power source is cer-
tainly acceptable but it is generally rather costly since the
surface speed of the guide roller must precisely match the
speed of the web or smeared prints will result.
PRINTING DIRECTLY ON MASTER ROLLS
Universal Non-Porous Mini-Coders can also be mounted on custom designed extension arms which will enable
them to print directly on the surface of a master roll of web material as it is unwound. This technique is frequently
used when conveniently positioned idler rolls are not available. In these applications, as the master roll of web
material decreases in size, the mounting arm pivots and keeps the print drum in constant contact with the
surface of the roll as shown in Figures 31 & 32.
You will note in Figure 31 that the coder is mounted in an orientation which will rotate the print drum in the reverse
direction of a normal web printing installation. This is an acceptable method of mounting the coder if it is more
convenient for installation on the parent equipment. In these installations, the weight of the coder is used to
supply printing pressure and typically the standard spring tension mechanism and mounting column are re-
moved. Custom mounting brackets and extension arms should be carefully designed to keep the coder in an
acceptable attitude when printing on a full roll of film all the way down to the smaller diameter of the core. For
more details on custom mounting systems, contact our engineering department.
FIGURE 30
FIGURE 31
FIGURE 32
PRINT DRUM
BEARER RING
MODIFIED
GUIDE ROLLER
NARROW WEB
MATERIAL
GROOVE
CUSTOM EXTENSION ARM
CUSTOM MOUNTING
BRACKET
MASTER ROLL
OF FILM
CODER
EXTENSION ARM
MASTER
ROLL
WEB TRA
VEL
PIVOT POINT
WEB PRINTING
Summary of Contents for MC-10 Series
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