Home' New Zealand Printer Magazine : December 2013 Contents 25
format inkjet specs
SPEED itself is not really a useful
specification but unfortunately,
it is one of the first sought out on
the brochure. In reality, people
confuse speed with productivity.
Yes, productivity is comprised of
print speed but it also involves
quality, ease of use and reliability. These
factors combined contribute to more
work out the door faster.
Some manufacturers are now using
mechanical print speed as their measure
of speed. Reading the fine print it appears
that the clock starts when the first drop
is squirted, and stops when the last drop
What isn’t included is receiving and
processing the job, initial head clean,
aligning the paper, head cleaning in-
between pages, cutting of the media and
drying time. The chart represents actual
measurements of a printer’s activities.
In the five minutes of activity only
1.5 minutes was spent putting ink on
paper. In five minutes, four A1 CAD
drawings were printed. Yet, based
on its mechanical print speed, the
manufacturer claims over 240 A1s per
To truly understand the production
capabilities of a system, you need to
run actual jobs representative of your
And always send more than one page
to the device so that you can measure
true production time.
IN the last decade, the market has
recognised drop size as a significant
contributor to image quality.
Drop size, measured in picolitres
(pl), is the volume of ink in each drop
squirted by an inkjet print nozzle. It is
important because when that drop hits
the substrate, its volume dictates the
jump in image density from nothing to
something. In some systems with a large
drop size, such as the Océ TCS 500 (24pl),
the large drop size can be beneficial
as it enables the device to print CAD
drawings very quickly. The down side
is such a large drop size makes shaded
areas and photos, especially in the
lighter areas, somewhat grainy.
On the other hand systems like the
HP Z6100 with a drop size of four-six
pl can produce very smooth changes
in image density but at the expense of
print speed for CAD and line drawings.
Current Epson systems have a
variable drop size where each drop of
each colour can be one of three sizes,
ranging from 3.5pl up to 17pl depending
on the print mode.
This provides an extra dimension to
the colour performance of these devices.
THE big question everyone asks: how
much ink is used to print a given job?
It is much easier to calculate in
the small format world as most A3/A4
devices have toner included with the
maintenance agreement for a fixed cost
per page regardless of coverage. In the
wide format world, ink is not included
and the quantity used is a variable cost
for every page printed.
The manufacturers provide costings
for standard ISO images but that is not
the whole picture. Ink is used in the print
head cleaning and maintenance routines.
I have seen one model use an extra 18ml
of ink in its power-on cleaning cycle.
Some systems recycle this ink, most do
Most modern wide format printers
have an internal log that shows ink used
per print but you have to print the job
to find out how much ink it uses. Most
external rips will calculate ink usage
before printing but I have seen instances
where, for a given job, the rip’s ink usage
calculations differs markedly from the
printer’s ink usage figures.
So how does one work it out? My
rule of thumb for comparison purposes
has been to work out the cost of ink per
millilitre (ml) and, if applicable, add to
this the cost per ml of print heads based
on the warranted life of the print head.
For example if a print head costing $200
is warranted for four litres of ink then the
print head cost is $0.05 per ml. This will
give a simple way of comparing ink costs
between different systems.
ALL systems are covered by warranty
under consumer law but there are a
couple of areas to investigate to make
sure you understand your entitlements.
Firstly, what components of the
system are considered consumables?
I have come across printers where
the carriage motor is considered
a consumable, good for so many
movements of the print head across
the page. Once this number has been
exceeded, then any failure of the motor is
not covered under warranty. Most people
consider a motor as a component, not
a consumable. You need to understand
what is and, more importantly, what isn’t
covered by the warranty.
The second point to clarify with
your supplier is: who does the service?
and what resources they have to do
so? In regional areas, this is even more
important. Are there trained service
people nearby and how are parts
Warranty and Service
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