Flexography | Lithography
Envelopes can be printed by several different processes. Several
factors should be considered when deciding what type of printing process would
best satisfy your requirements. You should consider the quality required, the
quantity and the type of image being printed. Shown below are brief explanations
of different printing processes that are used to print envelopes. The explanations
may help you determine the best process for printing your envelopes.
Also when determining what type of printing process will best
satisfy your printing requirements, you should consider the design
guidelines for each process. Considering the guidelines will help you
achieve the quality you desire on the finished product.
Flexography is a type of printing process that uses a plate
with a raised surface and fast drying fluid inks to print directly onto the
print material. The plates are made of rubber or photopolymer and are attached
to a drum on rotary printing equipment. Flexography would be printed while the
envelopes are being converted. On larger runs, this is a less expensive process
than lithography because it eliminates a separate printing process, but the
print quality will not be as good.
On small quantity runs, it is generally less expensive
to use the lithographic printing process due to the make ready charges
that would be charged for a special order printed with flexography.
Lithography printing is a printing process that uses a flat
plate where water is applied to the plate surface and is absorbed into the non-image
areas. Then when the ink is applied to the plate, the image areas accept the
ink but the non-image areas repel it since ink and water don't mix. The ink
is then transferred from the plate to a blanket which in turn transfers the
image to the printing surface. Lithography is a high quality printing process
used on envelopes after they have been converted into envelope blanks or into
a finished envelope. Lithographic printing is generally more expensive on long
runs than flexography because it is a separate procedure in the manufacturing
process. Even though it is more expensive, it is sometimes preferred because
it produces better quality than flexography.
Note: When printing a bleed on an envelope
before it is folded into the finished on an envelope before it is
folded into the finished envelope, whether it is by flexography or
lithography, allow for 1/8" bleed compensate for the converting
equipment's 1/16" tolerance in folding.
Thermography is a process that works along with
another printing process by the use of a resin powder, the printed ink, and
heat. The powder is applied to the ink while it is still wet and then is sent
through a heating process. The powder only sticks to the printed area. When
it goes through the heat process, the powder swells and creates a raised image
in the printed area. The coating hardens when it cools. Thermography has the
appearance of engraving but does not have the ability to obtain its fine details.
Thermography is used to add quality to your stationery, envelopes and business
cards without the cost of engraving.
Laser Thermography: If your thermographed envelopes
are going to run through a laser printer, you must be sure that laser
safe thermography is used.
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