DGS Buyers Guide - PPSG.indd

DGS Buyers Guide - PPSG.indd
FPO
Choosing the Right UV
Flatbed Printer
Océ UV Flatbed Buyer’s Guide
1
Printer format: hybrid/moving bed
vs. true flatbed
There are two basic system architectures used in flatbed printing:
MOVING MEDIA
The print zone is stationary and the media moves through it just
like a roll-to-roll printer. This architecture is found in hybrid
printers, often designed primarily for roll media printing but
with some rigid printing capability.
Carriage
Takeup table
Moving substrate
Feed table
A guide to selecting
the model that’s right for
your business
Are you considering adding a UV flatbed printer to your
business? Are you a bit perplexed with making the right choice
between all the printer models currently available? How do
you pick the one that’s not only right for your business today,
The hybrid design has no moving gantry and instead requires accurately moving
the substrate through the printer for the duration of the print.
but right for you in the future as your business grows tomorrow
and beyond?
You’ve come to the right place. This guide will help you make
sense of the complexities of UV flatbed printing technology.
TRUE FLATBED
The media is held stationary on a table and the printing system
moves over the media.
Whether your shop already produces large format digital prints
or you’re looking to add flatbed capability to your existing
quick-print, offset, screen printing, packaging or in-house
processes, the goal of this guide is to help you understand the
choices you need to make and what to look for when selecting
Stationary vacuum table
Carriage
Stationary substrate
Moving gantry
a UV flatbed printer.
By means of a vacuum table, the true flatbed architecture holds the substrate
stationary for the duration of the print cycle while the printhead carriage and
gantry moves across the media.
2
MOVING-MEDIA ARCHITECTURE
(A.K.A. “HYBRID” PRINTER)
The majority of low-cost hybrid, moving-media printers on
the market were designed as roll-based printers that have
been fitted with a belt drive system and/or removable tables
to accommodate the transport of rigid media through the
stationary printing area. This design was undertaken by printer
manufacturers to maximize existing print technologies, enabling
them to offer rigid media printing functionality in their current
design, at a relatively low cost.
MOVING-MEDIA PRINTER PROS:
• Lower capital cost, as the printer requires only modified media
handling capabilities and/or accessory tables to allow feeding
and exiting rigid media.
• Hybrid printers give shops a 2-for-1: the ability to also print
onto roll-based media using the same printer.
MOVING-MEDIA PRINTER CONS:
• Moving the media can result in skewing of the image,
requiring a reprint and resulting in unrecoverable time
and materials.
• This printer architecture typically uses pinch roller or
belt-drive systems that can leave marks on the print, and they
often require cleaning of the drive system between prints to
remove excess ink.
• Hybrid printers can only print on fairly lightweight media
that have at least one 90-degree angle because a corner is
required to start feeding the rigid media through the printer.
They do poorly printing on irregularly-shaped or non-square
items (unless an additional custom made jig is used to hold all
the pieces in position as they move through the printer), on
heavy substrates, or materials that have an uneven surface such
as plywood or framed canvas.
• Hybrid printers struggle with achieving sufficient registration
for double-sided prints.
• This architecture lacks the geometry required to tile large
images over multiple boards, which is a common application
for exhibition graphics producers.
• Although the printer footprint can be small, the working area
“footprint” is comparatively large, requiring space on both
feed and exit sides of the printer.
• Requires more operator intervention while printing to ensure
boards do not skew or miss-feed.
• Switching between roll-based and rigid-based printing
requires physically reconfiguring the system.
TRUE FLATBED ARCHITECTURE
Similar to screen printing, the true flatbed design holds media
stationary on a table, and moves the printing system over the
rigid substrate. Vacuum tables are often used in true flatbed
design, helping ensure that there is no unintended media
movement during printing.
TRUE FLATBED PRINTER PROS:
• The print quality is optimized because only the printer is
moving while the media is held stationary against a table. This
optimizes productivity by providing perfect and repeatable
bi-directional alignment and the physical registration (media
to image) is optimized resulting in
the highest possible quality images. This is even truer when
exotic piezoelectric printing technologies — such as grayscale
print heads — are used.
• In addition to any rigid media, the true flatbed architecture
enables any reasonably flat object to be printed upon, offering
the ability to produce many exotic and unusual applications.
• The true flatbed architecture enables easy edge-to-edge
printing (full bleeds), which can reduce finishing time because
no further trimming or cutting is required. Printing to prefinished pieces can also save time and money by eliminating
the need to print “overs” to cover the potential damage to a
printed piece in the finishing stage.
• Multiple boards can be printed simultaneously by simply
placing them on the flatbed. This is useful for smaller sized
materials, such as point-of-sale signs that are printed in
quantity.
• Double-sided prints can easily be printed in perfect register.
3
• Large displays tiled (over several boards) can be printed
in perfect alignment so that when assembled, there are no
discernable gaps caused by image/media skewing.
• The ability to print on irregularly-shaped or non-square items,
heavy substrates, unusually smooth media such as glass, or
materials that have an uneven surface such as plywood.
TRUE FLATBED PRINTER CONS:
• Initial capital costs can be higher than hybrid printers.
• Roll printing capability is not built-into the system requiring
an optional configuration.
TOTAL COST OF APPLICATION
• The ability to print on thick substrates such as flat
(pre-assembled) furniture, framed canvas and other
manufactured items.
The system cost of a UV printer should be only one criterion
when selecting which printer is right for you. Also consider the
total cost of application, which includes the following:
• A single footprint which requires a working space on one side
only, for substrate mount/dismount.
• Capital cost of printer amortized over 3 or 4 year period
• Requires little operator intervention once the device
begins printing.
• True flatbed systems with a roll media option can quickly
switch between roll-based to rigid printing. This can also
improve productivity as the rigid substrate can be pre-loaded
on the vacuum table during roll-based printing.
• Cost of ink, lamps, electricity and other consumables
• Cost of floor space for printer and workspace
• Consumption rate of ink and other consumables per square
foot of production
• Cost of parts and service on an annual basis
• Estimated production volume
• Estimated labour to operate
• Waste due to misprints
Stationary flatbed
• Extra finishing costs to trim non full-bleed prints
Hybrid
80"
180"
160"
CONCLUSION
Footprint comparison for 4' x 8' print production
Size Formats and Footprint Requirements
The footprint of a typical hybrid design printer (indicated by
the red dashed line) can be considerably larger than that of
a typical stationary flatbed design printer (indicated by the
green solid line). This can become a significant concern if
space is limited.
4
Understanding the total cost of the application is critical to
selling digital printing profitably.
Your decision on whether to purchase a hybrid-style machine
or true flatbed should be driven by the potential for producing
as much revenue as possible from a single printer, tempered
by the physical space you have or can afford to add. Be sure to
ask manufacturers for real-world ROI models that reflect your
business considerations.
Printhead technology:
grayscale vs. fixed droplet
Close up simulation of color
vignette using a six-color ink set
and fixed drop size
The use of light magenta and light
cyan inks produce smooth quartertones and highlights but at the
expense of using more ink to cover
the media surface to achieve the
correct optical density.
Years ago, inkjet manufacturers adopted six colour
(super-CMYK) printing which added light cyan and light
magenta to the standard ink set, substituting the lighter
colours for their darker counterparts in the highlights
and quarter-tones. This tonal substitution technique was
implemented to help overcome the problem of visual
graininess inherent in fixed dot, large droplet inkjet
technology. The added colours helped produce smoother
quarter- and mid-tones and smoother, less-grainy gradients.
Over time, this complicated and expensive method
became the defacto standard, and nearly all inkjet printer
manufacturers using fixed dot technology have since adopted
six-colour printing.
More recently, due to advances in piezoelectric inkjet
technology, some printer manufacturers began using grayscale
print heads that can produce variable dots by delivering
ink droplets that vary in size. By using smaller droplets
but placing them closer together, a print head can produce
sharp images with smoother gradients and quartertones. The
ability to jet larger droplets enables the print head to produce
uniform, solid colours. The ability to vary the drop size
produces images that rival photographic quality.
The volume of an ink drop is typically measured in picoliters
(a picoliter is one-trillionth of a liter). Generally the smaller
the drop volume, the better. Also, the greater range of
multiple drop sizes a print head is able to produce the better.
As a point of reference a modern desktop inkjet printer like
you would have at home produces a four picoliter drop size
allowing it to produce photographic quality images.
•
Close up simulation of color
vignette using a four-color ink set
with variable drop size
The use of smaller ink drop sizes
produces quarter-tones and highlights
using far less ink than a six-color
system to achieve the same optical
density.
CONCLUSION
Grayscale print technology is becoming more prevalent because
of its ability to deliver better quality prints using less ink, so this
part of your decision should be easy. Look for the print technology
that will suit the types of prints you produce the most. An array
of larger droplets is good if your output mix consists primarily of
solid colours. An array of smaller droplets is good if your output
mix leans more towards photographic quality. Ideally, the printer
you choose should be able to produce quality output for the entire
range of applications you offer.
Because grayscale printing does not require the use of
lighter colours to achieve quality results, ink consumption is
immediately reduced by more than 30% on average.
Many printer manufacturers now use some sort of grayscale
print technology because of its superior image quality and
cost reduction implications for the end-user.
5
Operational considerations
INK COSTS
Ink costs are more than simply the price per liter. How
much ink is used per print must also be considered. Only
by considering both can you have an accurate notion of the
projected costs per square foot. As mentioned in the previous
section, because grayscale print heads do not require the use of
lighter colours to achieve quality results, ink usage for a fourcolour grayscale printer will be less than that of a six- (or more)
colour fixed-droplet inkjet printer.
One common misperception about the price of UV inks is that
they are more expensive compared to solvent inks. On strictly
a volume basis, UV inks cost more; however, solvent inks are
mostly solvents with only a relatively small amount of pigment.
This solvent is volatile and evaporates away in the drying process
leaving a small amount of the pigment behind on the substrate.
UV inks have a higher concentration of pigment since they do
not need to evaporate but instead “cure” with exposure to highintensity UV light. As a result much less UV ink per square foot
is jetted onto the substrate, providing considerably greater yield
per liter than solvent printing.
Plugged nozzles
A hidden cost with many printers is the amount of ink that is
wasted in maintaining proper jetting of the print head nozzles.
This “purging” process forces ink through the nozzles in an
effort to clear any blockage. On some printers purging will be
done on all colours regardless of which colour requires it. Other
printers purge automatically without any instruction from or
interaction with the operator. This can quickly add up to a
significant cost in ink. An ideal ink system will enable the user to
select which colour to purge and when to purge.
POWER CONSUMPTION
Rising electricity costs are a reality in today’s competitive
market. You want to be sure your profits are not being drained
by the amount of electricity your printer consumes. Of the
models you’re considering, check the specifications to see how
much wattage and amperage is required. Ideally, you’ll want to
find a printer that uses the more common single-phase power
(instead of more energy-consuming three-phase) and less than
3500 Watts of peak power.
In addition to power consumption, you may need to add
compressed air. Some printer models require air to drive various
systems. This also represents a facility and ongoing operational
cost that should be considered.
Most printer manufacturers offer a pre-installation site checklist
that you can use during your research to help decide footprint
size, printer placement, electrical service adjustments, etc. This is
useful to calculate running and potential setup costs before you
purchase a printer.
USER MAINTENANCE
UV inkjet technology is more forgiving than solvent inkjet
technology in that UV inks cure rather than dry. Since UV
inks remain liquid until cured by high-intensity UV light, the
ink delivery system clogs less frequently and is therefore more
reliable. Some user maintenance is still required ranging from
daily purging and cleaning to periodic replacement of ink filters,
UV lamps, air filters, etc.
Nozzle test print close-up
The “nozzle test print” quickly identifies if there are any blocked
nozzles on each of the different colour printheads. By being
able to select when and which individual colour will be purged
wastes the least amount of ink.
6
ENVIRONMENTAL QUESTIONS TO CONSIDER
ELECTRICAL REQUIREMENTS
• Single- or three-phase power requirement
• Maximum sustained load
• Must it always remain powered on?
TEMPERATURE REQUIREMENTS
If jetting at ambient temperature, the environment becomes
critical in maintaining consistent print quality. Maintaining a
consistent ambient temperature, especially in a large, active work
space can be difficult and expensive particularly if costly HVAC
systems are required.
VENTILATION
INSTALLATION RESTRICTIONS
Requirements vary from office grade ventilation to 20+ room air
changes per hour.
Ensure that the printer can be moved into the printing room,
preferably without removing windows or walls.
RELATIVE HUMIDITY
CLEANLINESS
• Uncontrolled relative humidity of 30% or less greatly
increases static electricity on rigid media.
Since printing over dust, debris and fingerprints can produce
white specks and other undesirable artifacts on the prints, a
clean environment free of airborne dust and debris will greatly
reduce (the number of) wasted or ruined prints plus prolong
print head performance. Carpet should be avoided as should
placing the printer close to sources of contamination such as
routers, woodworking equipment, etc.
• Low relative humidity can also result in artifacts and reliability
issues.
• Some products have active static suppression solutions to
counter these effects.
CONCLUSION
FOOTPRINT
• Flatbeds are bigger but need no additional space for
media handling.
Make good use of any pre-installation planning documents
provided by the printer manufacturers.
• Belt/pinch systems require an equal board length on each side
to allow for media transport, up to 64 square feet of extra
space.
PHYSICAL ENVIRONMENT
Excessively heavy printers or those assembled from components
may require rigid flooring such as concrete.
7
Service and support
The printer you buy is a valuable tool of your business. It needs
to stay in top shape, and you need to have knowledgeable
backup for those (hopefully) few times it isn’t running properly.
After all, a printer that doesn’t run — or doesn’t run right — is
not making you money, and it may well be costing you money
in missed deadlines, upset customers and extra media/ink costs
for job re-runs.
Just as important as choosing the right printer is choosing the
right company to back it up. There are many reputable UV
flatbed printer manufacturers that may have a limited direct
level of service or support. To obtain the highest level of service
and support, be sure to research which companies factory-train
their technicians, and the ongoing training programs that keep
their technicians up-to-date.
Some companies will only service and support just the printer
they sold you and are not able or willing to provide training
and support for the applications you are trying to produce or
the software used in the workflow. This can often lead to great
frustration and expense when colours don’t reproduce correctly
or results are affected by using incorrect substrates. Ideally, your
equipment vendor can provide quality training in all aspects
of production — from file setup, to colour management, to
even helping select the best performing substrates for your
application.
ASK THE FOLLOWING QUESTIONS:
1. What is the length of the warranty period and what does it
cover?
2. Who services this printer? Technicians employed by
the manufacturer? A third-party service organization? A
technician working for the local reseller?
3. How are the technicians trained and by whom? Is there
ongoing training so they stay up-to-date?
4. What is the standard response time after I make a call
for service?
5. What quality of second level support is provided should
there be a delay in fixing the problem?
6. If a part is needed to which the technician doesn’t
immediately have access, how long will it take to get the
part? Where are the parts stocked and how long does it take
to get them?
7. If things go well during my warranty period, I may not want
to spend money on a service contract once it expires. What
are the pros and cons of this?
8. Can I service the printer myself?
CONCLUSION
Ensure the technicians servicing your printer are well-trained in
all aspects of the print workflow. Use the above set of questions
with every printer manufacturer you’re considering.
8
Curing technology
The most common UV light source used in flatbed printers have
been mercury vapor lamps. Mercury vapor lamps have a broad
spectral range with numerous peaks of UV energy. Free radical
UV inks are formulated to respond to these multiple peaks,
which together provide enough energy to initiate the curing
process.
The newest technology now finding its way into the flatbed
printer market is UV-LED. This technology shows some
promise in that it produces UV with less associated heat
byproduct making it suitable for use with very heat-sensitive
media. However, compared to mercury vapor lamps, UV-LED
lamps emit a much narrower spectrum of UV energy with single
rather than multiple peaks. As a result, ink formulations must
be carefully tuned to react properly to these specific wavelengths
of UV energy. This sometimes results in ink sets with a
considerably smaller colour gamut than those inks designed
for use with mercury vapor curing systems. The low power
and specific wavelength of UV-LED systems also often results
in less complete ink curing in the printing zone, leading some
manufacturers to offer secondary (offline) curing systems with
their printers.
COMPARING THE PROS AND CONS OF EACH
TECHNOLOGY WE CAN SUMMARIZE AS FOLLOWS:
MERCURY VAPOR PROS:
• Lower component cost, which can have an impact on the
purchase price of the printer.
• Tried and true lamp technology and ink formulations provide
high quality results.
• High degree of curing energy available for complete instant
curing and optimized productivity.
UV-LED versus Mercury Vapor Lamp
0.025
UV-LED
Mercury Vapor
Spectral Intensity (W/cm2/nm)
Liquid UV curable inks require exposure to high-intensity UV
light in order to cure the ink into a solid. This curing process is a
reaction initiated by the UV light reacting with chemical photoinitiators in the ink. This sets off a process of polymerization
leading to a solidification of the ink, all within a fraction of a
second.
0.020
0.015
0.010
0.005
0.000
230
280
330
380
430
Wavelength (nm)
From: Characterizing the Output and Curing Capabilities of Solid-State
UV LED Sources, Paul Mills, Phoseon Technology
UV inks require photo-initiators tuned to react to the peak wavelengths
generated by the UV light source used in the curing system. Traditional
mercury vapor technology provides a far greater number of usable
frequencies compared to UV-LED thereby allowing ink companies greater
flexibility in developing suitable UV ink formulations.
MERCURY VAPOR CONS:
• Consume more electricity per square inch of UV output than
UV-LED.
• Generate more heat on the media surface, which can cause
warping of very heat-sensitive media.
• Require a warm-up time of 30 to 60 seconds after being
switched on to reach optimal output intensity, and
mechanical shutters to switch light off and on during printing.
• Although inexpensive, lamps require replacement every
500–1000 hours of operation.
UV-LED PROS:
• UV-LED lamps consume considerably less electricity
— typically a 50-75% reduction in power consumption
compared to mercury vapor lamps.
• Generate less heat on the media surface enabling easier
printing of very heat-sensitive substrates.
9
• No warm-up time required and can be switched off and on
in milliseconds avoiding the need for mechanical shutters.
• Generally, the average lifespan of a UV-LED lamp is
thousands of hours. However, UV-LED lamps are typically
mounted in arrays that are very expensive to service if/when
they fail.
UV-LED CONS:
• UV-LED lamps cost more, subsequently increasing the cost
price of the printer.
• Good ink formulations are harder to develop and often result
in a smaller colour gamut.
• Higher UV-B and UV-C wavelengths can produce “tacky”
results in the finish of the cured ink.
CONCLUSION
Your decision should fit your business’ profile of not only the
applications you produce today, but ones you will pursue as
new business tomorrow. Be sure the technology you choose can
support your needs.
Inks — do you really need white?
WHITE INK PRINTING
Since most media printed with UV curable inkjet printers, be it
rigid or roll based, is white to begin with, the need for white ink
is limited to the realm of specialty applications. Some of these
special applications can truly benefit from the digital printing
of white whereas some applications could implement white in a
more cost effective manner. It is important to ask yourself some
questions before making a purchase decision of a UV printer
that features white ink.
HOW MUCH OF MY CURRENT WORK COULD USE
WHITE INK?
If you are producing second surface backlit graphics, it can be
less expensive and a more productive approach to manually
apply a white flood coat or an adhesive vinyl diffuser than tying
up your printer to print white. For more complex applications,
if you are applying white by screen printing or cut vinyl, this can
10
become expensive and time consuming, particularly for shorter
print runs. Digital printing is generally the same cost from the
first print to the last. You may be able to reduce your costs and
turnaround times by digitally printing white ink.
COULD I GET NEW WORK WITH WHITE INK?
Yes. Depending on the application, white ink can make a big
difference. Consider the applications that might use non-white
material, such as off the shelf rigid building materials, fabrics,
packaging materials, manufactured items, etc. Applications on
clear substrates are also popular such as backlit displays, window
films or even mirrors.
Many uses for white ink are simply limited by a designer’s
imagination or awareness. By reaching out to creative people and
informing them of your new capability, they can design for the
device and provide you a competitive edge over the
four-colour competition.
WHAT’S THE TREND?
Because the use of white ink has become very popular in recent
years, you may want to consider systems that offer a white ink
option. Not all systems are equal however. Some printers require
you to utilize existing colour channels for printing white – such
as light magenta or light cyan. This results in you being able to
print white but now with inferior looking CMYK results and at
the added cost of flushing all the light colour inks. Furthermore
the time it takes to switch over inks may take hours of valuable
production time.
WHEN SHOPPING FOR A WHITE INK CAPABLE
FLATBED HERE ARE SOME QUESTIONS TO ASK:
1. Is white ink available “on demand” without having to
replace/supplant existing colour channels such as light cyan
and/or light magenta?
2. If I have to switch over to print with white ink, how long will
it take and how much ink/flush will I waste?
3. Am I able to print white at the same time as my other colours
or is it a separate print pass?
4. Can I layer white and colours in any order and if so how
many layers?
5. How opaque is one layer of white ink?
6. What is the quality of finish in the white ink? Is it really
“white” or is it light gray or light yellow?
CONCLUSION
White ink capability can help expand your business into areas
beyond white paper or board products. If you’re not sure, check
with the various printer manufacturers as some models are
field-upgradeable to add white ink later.
Before the print: which RIP to use?
The RIP or “raster image processor” is a vital part of the flatbed
printing workflow. The RIP at its most basic level takes the
computer code that makes up your graphic and translates it
into a language your printer understands. Each pixel in your
jpg file or vector coordinates in your PDF are converted to a
representative drop of ink on the print.
Taking this another step further, a modern RIP can also
process the colour information in the file so you can properly
colour manage the entire process using what’s called an ICC
(International Colour Consortium) workflow. The ICC
workflow uses device “profiles” that characterize the numerous
devices in the chain from your digital camera to your image
retouching software, to your computer monitor to finally your
printer profile. Profiles can either be generated by you, or they
are often freely provided by printer and/or media manufacturers.
Proper use of ICC profiles ensures the best possible colour
match from device to device, printer to printer and location to
location. Even more importantly, they can ensure consistency
from day to day and operator to operator.
Some RIPs also provide an integrated Pantone® library for spot
colour matching using the power of the ICC workflow. This
means the RIP will automatically pick the closest colour match
to the spot colour used in your file.
11
A good RIP will also enable you to control your printing
workflow so you can accept jobs from your network
and direct them to the appropriate printer. Jobs can be
intercepted and edited for size, cropping, paneling, etc.,
before being sent to the printer, and print files can also
be archived for later use.
Finally, a RIP will also often process and provide data
to support digital finishing solutions in your workflow
such a flexible and rigid media cutting systems. Be sure
to understand the capability of the RIP in this regard so
that full integration can be achieved with your finishing
equipment.
THINGS TO LOOK FOR IN A GOOD RIP ARE:
CONCLUSION
1. Compatibility with your flatbed as well as support
for other printers you currently have or plan to have
in the future
Some printers are RIP-specific and there are no other RIP software
options aside from the one specified by the manufacturer. The
upside here is that these RIPs are sometimes finely-tuned to work
with the specified printer in ways a generic RIP cannot. Also be sure
the service technicians or applications specialists for the printer you
choose are fully trained on the RIP and can help you with questions
on workflow.
2. Consistency, predictability and scalability
3. ICC colour management and spot colour support
including white ink
4. Compatibility with digital cutting solutions
5. Compatibility with the graphics file types you use
6. Network connectivity so others can easily submit jobs
through hot folders or virtual printers
7. Presets that can be saved and applied to subsequent
jobs, limiting the amount of operator intervention
8. Processing speed to RIP complex files
9. Multiple printer support
10. Scalability
11. Support
CANON is a registered trade-mark of Canon Inc. in Canada. All other referenced product names
and marks are trade-marks of their respective owners and are hereby acknowledged. © 2014 Canon
Canada Inc.
Professional Printing Solutions Group
4711 Yonge St. Suite 1100
Toronto, ON M2N 6K8
416-224-5600 | 1-800-668-1945
Fax 416-224-5778
email: PPSGInfo@canada.canon.com
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