modifying inkjet printers

[Allan Adler]

In the January 26, 2008 issue of Science News, vol.173, pp.56-57,60,
is an article by Sara Webb entitled, "Life in Print. Cell by cell,
ink-jet printing builds living tissues". The point is that, apparently,
it is easy to modify an ordinary ink-jet printer to print with stuff other
than ink. In the article, they are printing with cells.

I'm not thinking of printing with cells, but it could be fun to print with
substances other than ink. So, I'm interested in knowing how one does this.
I understand that this probably isn't something I should do with a printer
I depend on. I would probably just use one I have found on the street
and don't care about.

Here is what they say at the beginning of the article: "Almost as soon as
ink-jet printers hit the market in the 1980s, materials researchers
realized that the machines could be used to deposit droplets of
substances other than ink. In principle, anything that could squeeze
through the printhead -- including plastics, silicon, or dissolved
metals -- could be laid out in some precise pattern."

They refer to an earlier issue of Science News in support of this statement
but it probably doesn't say how exactly to do it. If you know of articles or
books that explain exactly how to do it, please let me know.

 

[Arthur Entlich]

Interesting question.

Depending what substances want to "print" with, and what substrate you
want to print on, the answer as to what mods are needed range from none
at all, to possibly rather major.

However, which inkjet printer type is critical to all of this.

There are basically two current technologies available. One is called
piezo and the other thermal. Then there are some variations on the thermal.

I will start with thermal because you need to under stand it's
functionality to be able to compare it to the piezo.

Thermal inkjet heads come in several designs. Some are designed for
single use (one cartridge full) and are in fact part of the replaceable
cartridge unit. HP, Lexmark (Dell) and older Canon models use(d) this
technology. The other versions, used in all newer Canon printers, and
some higher end HP models uses a separate print head which can be
replaced when it burns out, which typically takes 18-24 months with
moderate to high use.

The advantages of the single use type is that you get a new head with
each cartridge, so should the head burn out, or get damaged or clogged
beyond repair, the fix is as simple as a new cartridge. The advantages
of the long term is it saves money on the cost of the ink cartridges and
is environmentally better because there is less to toss away, and it
allows for a more sophisticated type of head design.

The single use cartridges can be refilled, and in some cases will last
numerous refills, however, all thermal inkjet printer heads do degrade
with use. The reason for this is due to how they operate.

Thermal printers deliver ink to the head via some channels. close to
the nozzle opening there is a very small resistor which when current is
applied heats up and causes the ink to begin to boil. The pressure
created from this steam bubble being produced pushes the ink in front of
it out of the nozzle. The ink cools again, moves forward via capillary
action and another bubble is created to do the same thing. Originally,
thermal inkjet heads could only produce one size droplet. As the
ability to make heads with more nozzles became feasible and cheap, some
modern thermal heads have two or three different nozzles sizes for each
dot location and they can fire the appropriate ones for the ink dot size
required. The heads degrade due to the limited number of times the
resistors can go through the heating and cooling cycles and from the
continual heating and cooling process which eventually fatigues and eats
away nozzles.

Thermal heads have become much more sophisticated over time in design
and precision, and for the standard inkjet use they are designed for,
they are equal in image quality to their competition, the piezo head design.

However, for non-conventional use, they have some problems related to
how they function.

1) they use heat and heat the liquids, in many cases this may damage or
destroy the liquid (such as live cells). In some cases some inks
special inks harden when heated which would clog the head completely.

2) the thermal system requires a volatile which can be boiled at a
specific temperature and is not flammable.

3) ink viscosity and size of components like solids becomes critical to
allow the material to move properly

Perhaps one advantage if these other issues above will not harm the
process, is that the heads are replaceable easily by the end user so if
you mess up, you don't need to bring the unit in for a head repair, or
simple lose the whole printer is head repair is too costly.

However, by far, the most versatile print head design for "alternative
use" is the piezo head design. All Epson printers, and several other
lessor known brands use this technology. A few HP models did, although
I don't know if any current models do. Piezo uses a mechanical pumping
action. Basically, there is an ink chamber and a channel that leads to
an opening or nozzle out of which comes the ink. The "pump" between the
chamber and the channel is a small circular piece of piezo electric
materials that is sealed and held in place all the way around the edges.
This material changes dimensions when current is applied to it,
causing it expand, and since it is somewhat flexible, and held in place
be the edges, it goes from a flat shape to a concave (or convex,
depending which side you are looking at) condition. This sudden
movement creates pressure on the ink in the column and forces a small
droplet to be pushes out of the nozzle. When the current is cut, the
disk goes flat again, which both pulls the ink in the column back
slightly to end the droplet, and also to pull more ink from the chamber
into the column. The beauty of this design is many fold:

1) It requires and generates almost no heat
2) The liquid doesn't need to contain a carrier which boils at a
specific temperature and is non-flammable
3) the viscosity of the liquid can fluctuate and in fact piezo heads
have detectors in them to alter the speed and voltage to the head to
compensate for viscosity of liquids and temperature changes at the head
(within limits).
4) Unlike thermal heads, the size of the droplet is not based upon the
nozzle size, but on the frequency of the vibration of the piezo
actuation. Faster and shorter pumping makes smaller droplets, so the
same nozzle can produce many drop sizes (some Epson models produce as
many as 7 drop sizes per nozzle).
5) The heads are designed to last the life of the printer and each piezo
unit is designed to run for hundreds of millions to billions of actions.
6) the voltage going to each nozzle in the head can be programmed into
the printer at the factory and with proprietary software.

So, although I have not read this article, my guess is that for most
modified applications, Epson piezo inkjet printers are used.

Some examples of how inkjet printers are used, besides the cell
"printing" are to print conductive traces onto circuit boards, to print
parts numbers on items and parts (like medicines (the print on pills or
capsules), to make transparent edible pictures for cakes (using food dye
inks onto an edible sugar/rice paper), to print logos and number codes
onto the outside of fruit (so you won't have to deal with those horrible
adhesive stickers on each orange) (they also use dot matrix and lasers
for marking fruits) for all sorts of permanent plastic printing (using
UV hardening inks) to distribute very very minute quantities of liquids
for medications onto a surface, and radioactive materials, to build very
detailed nano products, to place glues and adhesives onto very precise
areas, and building small plastic devices and models using UV setting
plastics.

One of the most interesting areas where inkjet printers are being used
is in the "printing" of OLED (Organic LED) displays. The LEDs and
electroluminescent plastics (red, green and blue) are loaded into inkjet
cartridges and printed onto the substrate.

Pretty much anything which requires precision positioning and
measurement of quantity can be handled with some type of inkjet technology.

Art

 

[Allan Adler]

Interesting question.

Thanks very much for your detailed explanations of how materials other
than inks can be used in inkjet printers. If you don't mind, let me ask
a followup questions: once I've selected the material I want to use
instead of ink in the Epson piezo inkjet printer, how do I get it into
the ink chamber?

 

[Tony Hwang]

In the January 26, 2008 issue of Science News, vol.173, pp.56-57,60,
is an article by Sara Webb entitled, "Life in Print. Cell by cell,
ink-jet printing builds living tissues". The point is that, apparently,
it is easy to modify an ordinary ink-jet printer to print with stuff other
than ink. In the article, they are printing with cells.

I'm not thinking of printing with cells, but it could be fun to print with
substances other than ink. So, I'm interested in knowing how one does this.
I understand that this probably isn't something I should do with a printer
I depend on. I would probably just use one I have found on the street
and don't care about.

Here is what they say at the beginning of the article: "Almost as soon as
ink-jet printers hit the market in the 1980s, materials researchers
realized that the machines could be used to deposit droplets of
substances other than ink. In principle, anything that could squeeze
through the printhead -- including plastics, silicon, or dissolved
metals -- could be laid out in some precise pattern."

They refer to an earlier issue of Science News in support of this statement
but it probably doesn't say how exactly to do it. If you know of articles or
books that explain exactly how to do it, please let me know.

Hmmm,
Isn't it organic vs. inorganic substance for imaging?

 

[Arthur Entlich]

Well, I should be clear that not everything will work. There are even
limitations with a piezo head. You get your material into the ink
chamber by filling an empty and clean ink cartridge with the material.

Before going any further, unless this is a well funded project (and
perhaps, even if it is) my first approach would be to gather up some
older Epson printers preferably those which do not use the chip ink
level monitor on the printer cartridge (these would be printers made
before year 2000) and experiment. You can find these models used and
often for low prices or even free at thrift and other used stores or on
line.

The reasons I suggest these is because:

1) the cartridges are very easy to fill You may still be able to find
empty/virgin ones at some suppliers

2) if you damage the head in testing your material, it isn't any great loss

3) The heads may be more robust in design and handle more abuse.

However, there is one disadvantage of there cartridges. They contain a
batting or foam in them to hold the ink, making them difficult to clean
out, and that material may contaminate some other materials placed in them.

It will require you to clean the printer heads to flush them of old ink,
etc. To do that you may benefit from my Epson Cleaning Manual which is
available free of charge from me (at the email address shown at the end
of this posting) which explains how to clean the heads

If you go for newer printers, after about year 2000, the earlier models
will have the ganged cartridge design similar to pre-2000 (meaning one
cartridge will contain chambers for 3-5 colors, and one will contain one
chamber for black ink only), but they will have a chip attached to the
side of the cartridge which can be written to and read. This chip
indirectly keeps track of the ink in the cartridge, but once the
cartridge is empty it will read empty and even if you refill the
cartridge it will still read empty. You can purchase a cartridge chip
resetter for $5-10 on line. These ganged cartridges will also likely
have sponges or batting in them.

Starting in about 2003, Epson began introducing individual ink color
cartridges, These too use the ink monitor chip. The advantage to these
cartridges is that they generally do not use any sponge or batting, but
instead use some sophisticated chambers, labyrinths and values and pump
systems to control ink flow and air flow. They are more difficult to
refill, and Epson owns patents of their design which recently were
upheld in court making these cartridge designs more difficult to find in
North America in empty versions.

There are still a few companies offering easy refill versions of these
cartridges with either no chip (requiring you to take one from an OEM or
other source and if necessary resetting it, or a permanently auto
resetting chip. But, you may have to act quickly to get these because
embargoes on them will take place once Epson gets final approval of
their laws suits.

Finally, you need to understand that certain things just won't work with
these ink cartridges and head.

1) If the materials are very viscose they simply will not flow through
the cartridge to the head chamber and through the heads.

2) Anything that has a solvent in it which may dissolve the plastic
cartridge components or the head components will ruin both.

3) Anything that has high volatility and dries rapidly or has a fairly
large particle size will likely clog the heads and nozzles in short
order. The nozzle diameters are smaller than a human hair, as I recall.

Lastly, since Epson printers do not have user replaceable heads,
experimentation with unknown ink substitutes could prove costly due to
head failures and clogs that cannot be remedied without professional
intervention, if at all.

Art

e-printerhelp(at)mvps(dot)org

(at) = @
(dot) = .

 

[measekite]

Well, I should be clear that not everything will work. There are even
limitations with a piezo head. You get your material into the ink
chamber by filling an empty and clean ink cartridge with the material.

Before going any further, unless this is a well funded project (and
perhaps, even if it is) my first approach would be to gather up some
older Epson printers preferably those which do not use the chip ink
level monitor on the printer cartridge (these would be printers made
before year 2000) and experiment. You can find these models used and
often for low prices or even free at thrift and other used stores or
on line.

The reasons I suggest these is because:

1) the cartridges are very easy to fill

Filling carts is a messy proposition and the best carts are the ones
that come prefilled.

You may still be able to find empty/virgin ones at some suppliers

2) if you damage the head in testing your material, it isn't any great
loss

It certainly is. The head is probably the most expensive part of the
printer to fix.

3) The heads may be more robust in design and handle more abuse.

Who wants to abuse their equipment

However, there is one disadvantage of there cartridges. They contain
a batting or foam in them to hold the ink, making them difficult to
clean out, and that material may contaminate some other materials
placed in them.

It will require you to clean the printer heads to flush them of old
ink, etc. Mose mess
To do that you may benefit from my Epson Cleaning Manual which is
available free of charge from me (at the email address shown at the
end of this posting) which explains how to clean the heads

If you go for newer printers, after about year 2000, the earlier
models will have the ganged cartridge design similar to pre-2000
(meaning one cartridge will contain chambers for 3-5 colors, and one
will contain one chamber for black ink only), but they will have a
chip attached to the side of the cartridge which can be written to and
read. This chip indirectly keeps track of the ink in the cartridge,
but once the cartridge is empty it will read empty and even if you
refill the cartridge it will still read empty. You can purchase a
cartridge chip resetter for $5-10 on line. These ganged cartridges
will also likely have sponges or batting in them.

Starting in about 2003, Epson began introducing individual ink color
cartridges, These too use the ink monitor chip. The advantage to
these cartridges is that they generally do not use any sponge or
batting, but instead use some sophisticated chambers, labyrinths and
values and pump systems to control ink flow and air flow. They are
more difficult to refill, and Epson owns patents of their design which
recently were upheld in court making these cartridge designs more
difficult to find in North America in empty versions.

There are still a few companies offering easy refill versions of these
cartridges with either no chip (requiring you to take one from an OEM
or other source and if necessary resetting it, or a permanently auto
resetting chip. But, you may have to act quickly to get these because
embargoes on them will take place once Epson gets final approval of
their laws suits.

Finally, you need to understand that certain things just won't work
with these ink cartridges and head.

1) If the materials are very viscose they simply will not flow through
the cartridge to the head chamber and through the heads.

2) Anything that has a solvent in it which may dissolve the plastic
cartridge components or the head components will ruin both.

3) Anything that has high volatility and dries rapidly or has a fairly
large particle size will likely clog the heads and nozzles in short
order. The nozzle diameters are smaller than a human hair, as I recall.

Lastly, since Epson printers do not have user replaceable heads,
experimentation with unknown ink substitutes could prove costly due to
head failures and clogs that cannot be remedied without professional
intervention, if at all.

Art

e-printerhelp(at)mvps(dot)org

This is not a email address. It does not work

 

[Frank]

measekite wrote:

 

[Allan Adler]

Before going any further, unless this is a well funded project (and
perhaps, even if it is) my first approach would be to gather up some
older Epson printers preferably those which do not use the chip ink
level monitor on the printer cartridge (these would be printers made
before year 2000) and experiment. You can find these models used and
often for low prices or even free at thrift and other used stores or on
line.

The reasons I suggest these is because: [snip]
Finally, you need to understand that certain things just won't work with
these ink cartridges and head. [snip]
e-printerhelp(at)mvps(dot)org

Thanks for all your help with this.