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News
23/05/2009:
Virtual (digital) Proofing in Plate Mounting Improves Productivity and Quality
Submitted by Tim Reece, APR Technical Solutions Group
The first company that introduced the Virtual Image system and Virtual proofing is Systec Converting, Italy in 2001
The advancements made in the mounting process of photopolymer plates over the
last decade are undisputable. Using a multiple camera system with high
magnification to accurately align targets or micro-dots has not only increased
accuracy of registration, but has also greatly improved throughput. However,
while it is hard to argue the accuracy of modern video mounting systems, there
certainly has been room for further development regarding productivity. There
are multiple steps to the plate mounting process, but the three main steps that
consume the most time include wrapping the print cylinder with mounting tape (stickyback),
physically positioning the plate on the print cylinder, and pulling a proof to
insure proper registration.
Wrapping the cylinder and aligning the plates on the print cylinder have
proved to be necessary evils of the plate mounting process. However due to the
time needed to ink up the printing plates and pull a proof, some equipment
manufactures and convertors have decided to eliminate the feature from the
mounter or simply not utilize this feature. There is no doubt that video
mounting systems are very accurate or at least as accurate as the operator, but
waiting for a job to be pulled up in the press can prove to be a costly decision
when a registration problem arises.
It is for this reason that the most technologically advanced mounters have
incorporated a technology known as the virtual proofing or virtual imaging.
These innovative systems allow for the mounting of plates with or without out
crosses or references while allowing for virtual proofing without inks or
substrate. This virtual image effect may be used to both align the printing
plates during the mounting process, and/or capture an image of each mounted
plate and superimpose each plate on top of one another in a semi-transparent
image allowing for a virtual proof that ensures proper registration without the
added time of inking plates and pulling a proof proofing. The virtual proof also
minimizes previously needed proofing supplies and waste generated by these
supplies.
When using the system to mount plates, the operator mounts the first plate
and save that image. The image is viewed by the operator as a transparency and
the following plates can be overlaid with the image in the background. So you
can align plates with or without targets or micro-dots using this fast and easy
system. Equally as important, plates that have targets or microdots damaged or
removed are no longer deemed as unusable. The very latest in virtual image
technology adds further functions to the mounters with automatic smart control
of camera parameters for both overlay simulation and virtual proofing with
different magnification levels for a more advanced level of inspection of the
mounted job. It is even possible to save the jobs with the self learning systems
and the software drives the operator in the automatic mounting of a plate
sequence.
Truly today's most advanced virtual proofing systems have a reached a level
of both accuracy and throughput that we have never seen before, while reducing
consumables and waste in the mounting department. A common question regarding
these systems is, "How much time can I expect to save during the mounting
process when using a virtual image system?" The answer to that question varies
often according to the width of the cylinders. The technology does not add
additional time to the process; therefore by eliminating time spent to hang the
substrate on the impression drum, ink plates, pull the proof, clean the plates,
multiplied by the number of colors, will be the time one can expect to save.
Those who have already elected not to produce a proof will not necessarily see a
difference in throughput, until you factor in the insurance you have given
yourself by having an electronic proof. You no longer will rely on the printing
press to pull the first "proof". Therefore a reduction in re-mounts could be
expected which ultimately affects the throughput of the department
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