Water Based Piezo plotters (Epson 9000/7000 - Mutoh Falcon 4000/4100/6100 - Mimaki JV2-130 & Textjet, Roland HiFi Jet, etc. are using two up to seven Seiko Epson 64 nozzle piezo heads DX3.
The black head is a 64 nozzles (channels) head and the color a 4 or 5* 64 nozzles (channels) head.
The reliability of the print head is 2 billions of droplets of 40 to 3 picoliter giving a 23 picoliter medium size for normal poster printing.
To be more precise, the various sizes possible for droplets are:

• Micro:          40 picoliter

• Ultra-micro: 11 picoliter

• Super-micro: 6 picoliter

• Hyper-micro: 3 picoliter

THE DX3 PRINTER HEAD FOR DYE BASED INK

True 1440 x 720-dpi-resolution delivers text and line art that rivals an Imagesetter. Innovative 6-color ink system (Cyan, Magenta, Yellow, Light Cyan, Light Magenta and Black) provides astonishing photographic quality and color gamut surpassing current systems offered by other companies.
Proprietary ASIC technology controls the printing process. The result? Extremely high print-to-print and printer-to-printer consistency compared to other thermal or continuous flow ink jet printers.
DX3 Epson’s Dual Density Droplet technology offers precise 11-picoliter dot size for remarkably small, clean, sharp dot placement.
With every printing possibilities, the medium size of a droplet can be considered of 23 picoliter.
They are between 40 picoliter and 3 picoliter (EPSON Ultra MicroDot). In between, there is the EPSON Ultra MicroDot with 11 picoliter and the EPSON Super MicroDot with 6 picoliter of droplet sizes. Following the plotter producer, the 3 & 6 picoliter possibilities are cancelled or not.
The plotter adapt following the printing for one or one other resolution but the medium consumption is generally 23 picoliter/droplet, higher the resolution, smaller the droplet, at 1440 dpi the droplet is at 3 picoliter.

LIFE OF THE HEAD

The life of the head is limited at 128 billions of droplets per color and no matter if the droplet is 40 or 3 picoliter, only counts the impulse to produce the droplet.
We can calculate the theoretical volume of the life of the head as following:

• MicroDot: 5 liter 120 ml/color

• Ultra-MicroDot: 1 liter 408 ml/color

• Super-MicroDot: 768 ml/color

• Hyper-microDot: 384 ml/color

The medium consumption in Mutoh Falcon 4100/6100 is giving a volume of 23-picoliter/ droplet per channel  or 2 liter 944 ml/color during full life of the head.
The life is also limited in timing because the ink inside the head, short the life of the piezo system by the influence of the solvent used to produce the ink.

WARNING

Using the PIGMENTED ink short the life of the head for about 20% because the pigment inside the ink is acting as one abrasive.
To avoid any problems like head stocking or so, we advise to clean the heads with a cleaning flush after printing with pigmented ink.
It is very important to remember that these heads are build to use DYE based ink jet inks. It is possible of course to use PIGMENTED ink inside but the life of the head is shorter comparatively with one head printing only with dye ink.
We advise to print with pigmented ink only if it is no possible to avoid it. If you need to print for outdoor using with dry cold lamination, we advise you to print with the Prim Jet Color's DYE UV RESISTANT ink. Following the exposition, this ink resist from 6 months up to 12 months.

DX3 Piezo Head, Extract of Epson 9000 data

Web of references: Epson USA, http://files.support.epson.com/pdf/pro9k_/pro9k_pg.pdf

WARRANTY

The warranty gave by the OEMs is normally 6 months or 1.8 billions of droplets per nozzle (channel). For a medium consumption of 23 picoliter the warranty is, in fact, limited at 2 liter 355 ml of DYE ink per color.
The OEM are advising the printer that if the printer is using a compatible ink, dye or pigmented, the warranty on the plotter is loose. First, it is no legal for the OEM to cancel the warranty on the full plotter if the end user is using compatible ink.
Second, The OEM can only cancel the warranty concerning the printing system in direct connection with the ink. How cost in reality this famous warranty?

PRICE OF THE WARRANTY

The fact to buy OEM's cartridges to keep the warranty has one price.

The OEMs are only selling the ink in 220-ml cartridge for one price of, about € 99 / € 119 (so € 450 / € 600 the liter) for standard DYE Based ink and about € 125 / € 150 (or € 570 / € 750 the liter) for PIGMENTED based ink (Mutoh - Mimaki - Roland). Seiko Epson the head producer do not sell pigmented ink.

Exception the plotters like the Mutoh RJ800 or the Epson 7000 & 7500 using 110 ml cartridge sold at € 100 the cartridge (€ 910 the liter) for the black and the color at € 92 the cartridge (€ 836 the liter) 

Following the table showing how much you will spare using Prim Jet Color's inks.

Sparing cost based on 11 cartridges or 2 liter 950 ml used to cover the warranty in volume per color

SPARING COSTS

SPARING COST FOR THE BLACK COLOR

TOTAL SPARING COST FOR THE 3 COLOR HEAD

TOTAL SPARING COST FOR 4 COLOR PLOTTER

TOTAL SPARING COST FOR THE 5 COLOR HEAD (C/Y/M/ + LC/LM or + ORANGE / GREEN)

Price of one head: Black or color € 240.00 + work

As you can notice bellow the money paid to keep a warranty of a piezo head which cost € 240 + work , cost in fact up to € 6342.50 for 5 pigmented colors.

Following an extract of FLAAR report about piezo head. FLAAR is an independent association of specialized journalists in wide format plotters.

FLAAR REPORT ABOUT PIEZO HEAD

Site prepared by the FLAAR, Digital Imaging Technology Center, a non-profit research institute dedicated to assisting people learn how to use advanced digital photography and digital imaging in their own work http://www.large-format-printers.org/

Myth #1, piezo print heads are permanent.

Facts: The piezo print head people want to induce you to buy piezo print heads on the premise that you save money.

Reality of the matter

Piezo print heads self-destructs more often then piezo printer people would like you to know about. We have a report from one Roland user who indicates his heads don’t last much past 300 feet ( 100 meters) of media. 

Even Roland apparently told him the print heads had to be replaced every year. So much for "permanent" print heads with piezo.

We also got another e-mail that said his head self-destructed if it ran into dust or debris on the vinyl. If I remember correctly I believe it was a Roland system. 

Piezo print heads also self-destructs if they hit a ripple in the media (caused by too much ink which causes the paper to bubble up). Piezo print heads also self-destructs on at least one kind of Roland media; this infamous media curls at the edges. This results in the print head hitting the raised part of the curl every time the print head makes a crash. Kiss your piezo print head goodbye. We have several reports on this "head strike" problem; seems to be generic. 

Roland has stopped selling this media but there is lots of it still floating around.

If you leave your printer for 3 months without use, yes, any print head will cog  because the ink dries out and blocks everything. Most service contracts will cover this to some degree; some warranties may cover this. One Roland dealer quoted a price of over $ 500 for the replacement, per print head (covers print head and the house call). So that’s $1000 if both your piezo heads get clogged or have a head-strike or are otherwise Epson piezo-electric print heads are used in Bellise, Epson, Roland, Mimaki, and Mutoh. 

Mimaki is rebranded as Stork. Mutoh is rebranded as Agfa, I-Jet, Accuplot, Kodak, Digital Painter and PrimJet of one of the sign companies. 

Realize however, that not all piezo heads are from Epson (some are from Xaar)

Another Myth: " Piezo print heads do not clog"

In general piezo heads are known to get clogged nozzles quite often, having to clean them requires ejecting ink through them. This process takes time, and may use up quite a lot of ink!

If you have to print in a dusty environment remember that Roland is definitely dust sensitive, even from the media itself, so be sure your source of media is super dust-free.

As soon as we learn the degree to which other kinds of heads suffer similar problems with dust or debris on the surface of the media we will add those observations to this report. We update FLAAR reports sometimes as often as every day.

Nonetheless, there is nothing wrong with Roland, Epson, Mimaki, or Mutoh piezo print heads. The quality of a Roland printer is among our favorite (as long as you get one that does not band). Piezo print heads do their job quite well. 99% of users will unlikely lose a head because of dust on the media. 

But just don’t presume the heads will last forever. We get the impression that replacing piezo heads is more common (and more costly) than most people realize.

So far the only place I have noticed a piezo print head claim to being permanent is in the Gretag advertisement for its new Carolina textile press. I quote: "Compared to thermal print heads, piezo heads are permanent under normal operating  conditions. (piezo heads) are designed to last for the life of the printer. "I can only say that Gretag must be using heads other than Epson heads, because not even a sales rep has claimed the Epson heads are permanent. Roland heads in particular (from Epson) bite the dust regularly.

 

OEM's Dye Ink Durability

It is well known and documented that Epson prints fade faster than almost any other inkjet print. It is gradually becoming known that some Epson paper will also discolor, under some circumstances.

I do not have much data on Roland, Mutoh, or Mimaki dye based inks but there is certainly not much acceptance that they last as long as the inks by Prim Jet Color or Encad for thermal print head designs. 

 

OEM's Piezo Ink Durability

Studies in ink Durability vary between bait-and-switch to what a novice would consider close to misleading. The most infamous case is the "200 year + claim by Epson for its new encapsulated inks. 

I was at DRUPA trade show where these inks were premiered. I have it on good authority that the ink chemistry was still not finished and that the first inks which were used were judged unsatisfactory. 

Back to the chemical laboratory. Thus the question arises (which few people have asked in this manner), namely, how could anyone make a Durability claim for an ink that was perhaps not the same ink actually sold today? In any event, the Durability claim was cut in half shortly thereafter.

All that said and done, the durability of fine art prints done with a printer using Epson print heads may be less than you (or your clients) expect. 

The tests are based on darkened conditions, indeed Epson even admits that prints from some of its printers must be sealed completely in glass or the ozone alone will cause the cyan to react inappropriately, and evidently within a matter of weeks or months. If you use a Roland remember that it’s inks come via Epson, since the Roland uses the Epson print heads (as does Mimaki and Mutoh).