High Performance Solid Ink Technology

High Performance Solid Ink Technology
In the eleven years since its introduction, solid ink
printing technology has proven itself a powerful
performer, demonstrating unique and important
benefits in the desktop color printer market. The
technology has benefited from enhancements that
have extended its fundamental virtues of brilliant
color print quality, high performance, ease of use,
reliability, media flexibility and low cost.
This white paper presents an overview of solid ink
printing, with discussions of application areas and
comparisons to other color printing technologies.
Solid Ink Timeline
300 340 350
840 850 860 8200
Phaser® solid ink printer timeline
High Performance Solid Ink Technology
The Application Challenge
Science Elevated to an Art
Worth the Effort
Desktop color printers are expected to address
a broad range of applications. The major
application areas of office printing, business
graphics and graphic arts place different
demands on a color printer. User expectations
range from fast printing of text documents,
to flawless rendering of complex PostScript®
files, to accurate color matching for graphic
arts or pre-press work.
The success of solid ink requires the union of
physics, chemistry, electronics and
manufacturing expertise. This begins with the
ink, which has the critical property of
remaining in solid form until heated to a very
specific temperature whereupon it turns to
liquid; cool it just slightly and it almost
instantly returns to a solid. This is the key to
the vibrant color solid ink provides on just
about anything: molten ink is jetted from the
print head to a heated drum, where it remains
in a malleable state that ensures precise
transfer to the paper. This reduces the amount
the ink can wick into the paper fibers, keeping
the colors vivid while controlling the dot
spread that can reduce image quality.
A well-designed printer should be as close to
invisible as possible. The goal of the user is to
get printed pages, not think about the printer.
That sums up the target of solid ink technology.
But, it’s worthwhile to note that there are some
extraordinary things going on behind the
scenes to make it all happen. For example,
solid ink is applied through orifices smaller
than a human hair; the successful manufacture
of the print head requires stringent clean room
processes. Years of investment, research and
experience have been required to develop inks
and print heads that work together as a system.
Xerox is committed to this technology for one
simple reason: it delivers user benefits no other
color printer technology can provide.
The design and implementation of desktop
printing technology is further challenged by
the “human factor.” For instance, what is the
typical user required to know to successfully
use the printer day in and day out? How well
does the driver software integrate the printer
into the user’s workflow? How quickly can
printing consumables be replenished? How
many users can share the printer before print
times become unacceptably long?
The desktop color printer market is served by
two major technologies: solid ink and laser.
Each of the technologies uses a significantly
different method of printing an image. From its
inception, solid ink technology has been a color
printing technology. Color laser printers are an
adaptation of pre-existing monochrome (black
and white) office printers, so they are familiar
to most users of desktop workgroup-class
printers. But, as we will discuss further, color
laser’s evolution from monochrome laser
technology results in some inherent limitations.
Solid ink technology uniquely addresses key user
requirements, expectations and human factor
issues by virtue of its image creation method,
simplicity, ease of use and remarkable print
quality on the broadest range of print media.
Highly magnified views of color laser (left) and
solid ink (right). Note the gaps in the printed
areas in the laser image vs. the dense, crisp
appearance of the solid ink image.
High Performance Solid Ink Technology
Smaller Working Space
Compact Size
Pressure Roller
Printed Image
Print Head
Major Components of a Solid Ink Printer
Fewer Parts for Better Reliability
A solid ink printer consists of only three major
assemblies: the print head (applies ink to print
drum), the print drum (transfers image to
paper) and the controller (the brain of the
printer that converts data from the computer to
information required to print the image on
paper). Add a cabinet and a paper tray and you
have a solid ink printer.
For many organizations, floor space is a
critical resource. Here is where the compact
design of solid ink printers provides another
benefit. Compared to color lasers, solid ink
printers require much less space. While its
footprint, or physical size, is smaller, even
more important is solid ink’s smaller working
space requirement. Working space includes
access for print trays and routine printer
maintenance. In the comparison diagram, the
significantly smaller working space needed for
a solid ink printer compared to a laser becomes
evident. Solid ink printers can be integrated
into more environments with less impact than
color laser printers.
Color Laser
32 inches
Solid Ink
20 inches
29 inches
50 inches
Working Depth
This simplicity is responsible for the high
reliability, ease of use and low cost of solid
ink. With fewer parts, there’s simply less to go
wrong. In short, solid ink printers do a lot
more with a lot less.
Rugged Construction
Rather than using the more common bent sheet
metal, Xerox uses a one-piece cast aluminum
frame in its solid ink printers. This allows for
tighter mechanical tolerances that yield both
improved mechanical reliability and print
quality. The solid construction also contributes
to the printer’s durability.
Stringent Manufacturing
Xerox manufactures the solid ink print
head in clean rooms to ensure performance,
consistency and reliability. Xerox operates a
world-class chemical plant to produce solid
ink, with a state-of-the-art controller to ensure
batch consistency. To deliver the reliability that
solid ink has become known for, Xerox
employs 100% inspection rather than the more
common statistical sampling—every ink batch
must meet specifications before it is shipped to
the customer.
High Performance Solid Ink Technology
go by
How Many Passes Does a Laser Need?
Looking at Laser
Increased Image Quality
Color laser printers create an image by fusing
powdered toners to paper—the toner is melted
onto the paper. Depending on their
architecture, they can have almost three times
as many parts as a solid ink printer. Color laser
printers typically include parts such as
photoconductors, transfer rollers, fuser rollers,
fuser oilers, waste toner bottles and four toner
cartridges, all of which wear out or whose
contents are consumed during printing. The
life expectancy of these components is tied to
either the number of pages or the amount of
each color printed. Even worse, these parts
need to be replaced independently of each
other. This requires frequent maintenance and
user interventions. It also means that adding
even a little color to an otherwise black and
white page can significantly increase the cost
of that page.
Solid ink printing delivers superior quality in
three key areas: media flexibility, color
consistency and transparency printing.
Another advantage of the solid ink architecture
is the simplicity of the imaging process itself.
A wide variety of media can be easily and
Toner Cartridges
Laser Scanning Unit
Cleaning Blade
OPC Drum
4-Pass Laser Mechanism
reliably fed through the simple paper path.
Heavier stock and certain common envelope
types can be fed through the manual feed path.
Because solid ink is transferred from the print
drum to paper in a precisely controlled
malleable state, there’s little spreading of ink
into the paper. This makes its color quality far
less dependent on the surface allowing it to
maintain excellent color quality on the broadest
range of media types. In demonstrations, color
solid ink images have even printed on paper
towels, and while this is not a typical application,
it shows the capability of the technology.
Solid ink has exceptionally consistent color
quality from page-to-page, an important
attribute for long print jobs or multiple prints
of the same page. Again, the characteristics of
the technology deliver the benefit. Millions of
colored dots are applied to a page to create a
color image. The quality of the image depends
on consistent dot size and consistent dot
placement. Solid ink does both extremely well.
It’s more difficult for color laser to maintain
this accuracy. Dot size varies (laser dots are
clumps of toner particles that can scatter on the
paper) and there’s sufficient jitter in the laser
system so that misplacement of dots occurs. As
a result, color shifts can occur with laser, as
well as banding within areas of solid fill color.
Solid ink also has a major advantage in its
ability to print superior overhead
transparencies. Producing high quality
overhead transparencies is a demanding color
3. Paper is pressed on drum, transferring ink to paper
All of these attributes contribute to an
exceedingly simple automatic two-sided
printing capability. After printing the first side
of the sheet, the paper is re-fed from the exit
rollers back into the printer through a very
short path. It then quickly passes through the
high-speed imaging process a second time and
is delivered to the output bin.
1. Drum spins
Ink on drum
before being
transferred to paper
2. Print Head sprays ink
onto drum, creating
complete image
Heat keeps ink in liquid state; ink
drops are pumped onto
heated drum
Ink Supply
Solid Ink Printing Process
While solid ink technology has always printed
pages with a single pass through the printer,
the vast majority of color lasers in use today
use 4-pass print engines. This means three
important things:
• The mechanical complexity of the
printer is much greater
• The printer is more prone to print quality
problems—the shuttling of the paper can
cause misalignment of the tiny dots that
create the image
• The printer will take longer to print than
a solid ink printer
The newest generation of color lasers includes
models that print with a single pass. They’re faster
than the older 4-pass designs, but they’re still
lasers, so they’re still slower on most office print
jobs (see page 5), have more maintenance items
than solid ink printers and relatively speaking,
there aren’t many of them installed yet.
printing application. While the mechanical
process of applying the colorant (ink or toner)
to transparency film is the same as printing on
paper, the way the resulting image is viewed is
significantly different. When viewing a paper
print, the viewer is looking at ambient light
(the light illuminating the viewing area)
reflecting from the image area (where colorant
is applied) and the blank paper, which
typically forms the white areas of the image.
When viewing a transparency, light from the
projector is transmitted through the
transparency film and colorant and then
focused through a lens onto a screen. This
places different demands on the colorant;
issues such as flatness (to avoid creating a lens
effect) and uniformity of thickness (affecting
density of color) become very important.
During printing, the print drum in a solid ink
printer smoothes the solid ink, creating a flat
surface that transmits light well, making for
dense, saturated colors. Laser toner has a
rougher surface that doesn’t transmit light as
well, resulting in less vibrant color.
High Performance Solid Ink Technology
How Long is a Print Job?
Xerox tabulates solid ink customer usage.
Most jobs are under 5 pages and many
are 2 pages or less!
First and Fastest
A paramount measurement of printer
performance and one that Xerox labors over
unceasingly is print speed. The most complete
measurement of print speed is called
“throughput.” It’s the elapsed time between
clicking the “print” button on the computer
screen and the moment the finished print job
arrives in the printer’s output tray. Solid ink
excels in overall throughput by delivering
fast first-page-out time and fast color
print engine speed.
First Page Out Time
Solid Ink Printer
Color Laser Printer
9 sec
14 sec
Color Laser Printer
28 sec
Power-Point Presentation (8 pages on transparencies)
Solid Ink Printer
Color Laser Printer
Easy to Operate
Loading ink in a solid ink printer is often
compared to loading another common office
device: the stapler. The shape-coded inks are
simply dropped into slots on the top of the
printer. Even a child could easily match the
solid ink colors and shapes to the appropriate
slot and drop them in. There’s nothing to spill
or vacuum out of the carpet. Inks can be
replenished at any time, even during printing.
Reloading on the fly is not possible with any
other printing technology because they store
ink or toner in sealed containers inside the
printer. When the ink/toner is exhausted, the
entire container must be replaced with a fresh
one. Obviously, to avoid wasting money, this
is not done until the contents are completely
depleted, which interrupts printing.
18 sec
Color Letter
Solid Ink Printer
Xerox’ solid ink printers have a very short
paper path so the paper has a minimal distance
to travel to receive the image. It starts printing
without any special synchronization. As for a
warm up period, solid ink printers do not have
a fuser roller to heat, but they do need to melt
the solid ink at the beginning of the working
day. This is accomplished by software that
tracks the printer’s usage and warms up the ink
just before the first page of the day is due to
arrive. All of this results in a first-page-out in
as little as nine seconds, the fastest in the
industry. Solid ink printers have the fastest
speed for small, frequent print jobs.
3 min 5 sec
3 min 31 sec
The combination of color-optimized
architecture and fast controller/processor
leads to what is perhaps the most important
advantage of all for typical office color
printing: fast first-page-out time. Since most
print jobs are only one to five pages long
and only one copy of the document is printed,
the time it takes to print the first page can
be a significant factor in total color
printing throughput.
On the first page of a print job (which is often
the only page) a color laser must synchronize
its imaging components and paper path. This
lengthens the print time. Also, most color
lasers must warm up their fuser roller before
printing can begin. In fact, color lasers typically
achieve their rated speed only on multiple
copies of the same image. This is because they
must have more than one sheet of paper in the
paper path to achieve optimum timing.
Solid ink has been designed from the ground
up as a color-optimized printer. Xerox uses
this technology in printers that are rated up to
16 color pages per minute. Color laser
technology is essentially a monochrome
(single color) print technology that has been
adapted to print with four colors, using cyan,
magenta, yellow and black toners. In many
ways, it is like putting the complexity of four
printers into one cabinet.
The simple task of adding solid ink can be
done at any time— there is no need to wait
until the ink runs out. By simply topping-off
the ink before a big job, or whenever
convenient, users can be assured that their
print jobs will be completed without
interruption. Again, this is not possible with
any other printing technology for the same
reason as described above.
These attributes make solid ink the best
choice for the majority of users, who are
concerned about getting their prints, not
about maintaining their printers.
High Performance Solid Ink Technology
True Productivity
What Price Solid Color?
For a printer to be truly productive in a busy
office it must be easy to set up, easy to use
and easy to share. The hidden costs of printer
downtime, user frustration, and delayed print
jobs can be enormous. For example,
purchasing a low-cost but underpowered or
hard-to-share color inkjet printer can be far
more costly in the long run than investing in
the right tool for the job. Likewise, the
complexity of using and maintaining a color
laser can have significant productivity costs
from the very beginning.
As anyone who’s been around computers for a
while knows, the performance keeps
increasing, while prices decrease. The
price/performance ratio for color solid ink
printers has followed the same trend. It’s now
possible to buy a color solid ink printer for
about the same price as a network
monochrome laser printer.
Nowhere are the differences in solid ink and
color laser design more apparent than in the
experience of day-to-day printer use. Color
laser printers have up to nine different
mechanical consumables (assemblies that are
depleted during printing), while Xerox highperformance solid ink printers have only one.
The number of user interventions and the skill
level required to maintain a solid ink printer is
a fraction of that required by even the simplest
of color lasers. The only mechanical
consumable in solid ink printers is a long-life
maintenance roller that supplies the oil for the
imaging drum. The environmentally friendly
replacement rollers last for up to 40,000 pages
and can be installed in less than a minute.
What about Liquid Ink Jet?
Liquid ink jet technology does not work well in
multi-user network environments. The major
issues are slow print speed, low consumables
capacities, high levels of user intervention and
high print cost. Low acquisition cost might
make liquid ink jet printers appear attractive,
but they present a case of false economy for
workgroup use as organizations discover
how much attention they require and how
surprisingly expensive they can be to operate.
These printers require special, expensive,
coated paper to deliver their best print quality.
Solid Ink Measures Up
By virtue of its unrivalled simplicity and
unique strengths, solid ink technology
satisfies a broad range of user expectations
and requirements.
• Fastest printing of most common office
print jobs
Environmentally Sound
The unique solid ink printing process provides
yet another benefit: minimal environmental
impact. As previously noted, solid ink printers
have only one consumable item, compared to
numerous consumables in color laser printers.
The result is dramatic: after 100,000 prints,
a color laser can produce over 122 pounds of
waste, while a solid ink printer produces only
6.5 pounds. Solid ink printing results in less
waste going into landfills.
• Unsurpassed ease of use means
printers can be used by anyone with
maximum productivity
• Ability to print bright, vivid colors on the
broadest range of paper types
• Rugged, durable design goes the distance
• Small size allows printers to fit in almost
any environment
• Low acquisition cost for superior value
• Minimal environmental impact
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