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Sean
12-28-2006, 03:56 AM
I had a thought to take a device such as this:

http://www.inkjetmall.com/images/niagara-7600.jpg

And replace the continuous flow ink containers with a jug of warmed emulsion. I have heard of biologists modifying printers to print biological material to glass, paper, etc (I am unsure what models they used). From what I have read this material they printed seems to have the consistency of emulsion. If possible this could create an easy to use system that makes perfect coatings on a variety of papers. I would think the emulsion would settle on the paper as well removing any trace of a dot pattern and papers could be run through for double coatings etc. This could be one possible future where we buy jugs of our favorite emulsions then simply use inkjet based technology to coat the paper. The ease of use would be the main attraction by making coating almost effortless with a high degree of quality control. Anyone care to give this a try? I'd have a play but don't have the time to research and modify a machine..

markbb
12-28-2006, 04:16 AM
hmm, wouldn't this create a 'speckled' image, unless the emuslsion soaks into the paper to join up the dots?

Sean
12-28-2006, 04:46 AM
hmm, wouldn't this create a 'speckled' image, unless the emuslsion soaks into the paper to join up the dots?
There should be a way for the coating to go on slightly more thick, then it will settle into one uniform coat? dunno..

Dave Miller
12-28-2006, 09:12 AM
Now look Sean, if you have nothing better to do than hallucinate then you had better put your wife on-line so that we can ask her to sort out a few chores for you to keep you occupied.

David A. Goldfarb
12-28-2006, 10:34 AM
Gelatin based emulsions harden as they cool, so it might work for a minute or so before the heads and feed tubes get clogged up, presuming the emulsion isn't too viscous to get through the print heads in the first place. I suppose the heads may stay hot enough to keep the gelatin liquid, but I think the feed tubes would clog before you could coat a large sheet evenly.

6x6x9
12-28-2006, 12:28 PM
How about something like this? http://www.otsm.com/fuji/Q3_PRO_System_op.JPG

JBrunner
12-28-2006, 01:39 PM
Check it again. :)

http://www.apug.org/forums/showthread.php?t=10896&highlight=ventilation

Sean
12-28-2006, 01:55 PM
Gelatin based emulsions harden as they cool, so it might work for a minute or so before the heads and feed tubes get clogged up, presuming the emulsion isn't too viscous to get through the print heads in the first place. I suppose the heads may stay hot enough to keep the gelatin liquid, but I think the feed tubes would clog before you could coat a large sheet evenly.
Sounds like a roadblock but not a show stopper. The containers, tubing and heads will have to be maintained at a certain temp. Might be best to have the container and the head in one piece that is kept warm. Also custom heads may need to be developed. Now who has a few million for R&D? :p

Sean
12-28-2006, 02:19 PM
Some info about cell printing:


Recent reports have shown that an inkjet printer can be modified to put live cells on to a substrate [7,8]. Xu et al. [8] printed two different kinds of mammalian cells, an epithelial cell line [CHO (Chinese-hamster ovary) cells] and rat embryonic motoneurons, with good viability through the printing process. Survival rates beyond several days, however, appeared to be compromised, indicating potential limitations in this approach. The inkjet printing process is harsh, with very high temperatures (in excess of 300 C) and shear force (so high it is difficult to measure), generated in the nozzle. Most cells, especially delicate ones like neurons, are likely to be compromised during this process. In addition, because the tip of the nozzle is not much bigger than a cell body (20–30 μm), cells can clog the tip.

These technical challenges may now have been overcome through the use of a modified version of the inkjet. In this issue of Biochemical Journal, Eagles et al. [9] demonstrate that EHDJ (electrohydrodynamic jet) printing technology can be modified to deposit droplets of living cells from a nervous-system-derived cell line. Applying a voltage of approx. 30 kV between an electrode and the print nozzle causes the contents of the nozzle to be expelled and disperse into droplets. Although the tip of the nozzle in inkjet printing is restricted in size, an EHDJ nozzle can be much larger, reducing the shear force and the chance of clogging. Two exciting findings from this paper are that: (1) CAD cells, a neuron-like cell line, can withstand the applied voltages used in electrospraying, attach to the substrate and remain viable, suggesting that neurons could withstand the printing procedure as well, and (2) 1 month after printing, at least some cells that survived the printing procedure could be induced to extend processes and take on a neuron-like phenotype. Now that living cells from a nervous-system-derived cell line have been printed on to a substrate successfully, the answers to two key questions will test the potential of this new EHDJ technique. The first question addresses the precision with which cell ejection can be controlled. For example, can cells be printed to a specific predetermined spot on a surface? The second question addresses the robustness of the method. Will neurons that have been dissociated directly from nervous system tissue withstand the EHDJ printing procedure? If fragile primary neurons can be printed accurately, then this new method will open the door to high-precision neural-circuit building.

David A. Goldfarb
12-28-2006, 02:24 PM
That settles it. I'm giving up silver, and from now on will print exclusively Chinese hamster ovaritypes.

Sean
12-28-2006, 02:37 PM
lol

ben-s
12-28-2006, 05:46 PM
On a semi serious note, this is precisely how most 3D printers work.
Many use wax as a production material.
I once saw one loaded with a starch based substance, and it could print a reasonable looking (and just about edible) pizza base. :D

Wouldn't it be simpler to use a device more like a scanner, (upside down and sans glass) with a row of closely spaced jets across the head?
You could heat the whole head arrangement up, and apply pressure to a reservoir of melted emulsion to spray it out.
Then, if you varied the speed of the head, you could adjust the coating thickness.

Any volunteers?

Greg_E
12-28-2006, 07:47 PM
What temperature do you need to keep the goop at? That was an Epson inkjet that uses piezo electric heads (Epson 7600 or 9600 to be exact)... I have a lot of experience with the previous 9500 printer. I would not recommend using the 7600 as the heads have a smaller nozzle and it generally uses finer drops. I would recommend getting a old (but functional) Epson 3000 printer (4 color) and drive it with something like Quad Tone RIP to put down a little extra goop. Viscosity will be the biggest problem unless the emulsion flows like water, anything thicker will not work. Also heat is the enemy of the piezo heads, too warm and the heads will stop working.

Note also that there are many industrial piezo inkjet printers that could do this job, mosy of the UV cure should be able to do it, but they cost more than $10,000USD to start.

And goop = whatever you are spraying.

Tell me more about the exact needs for the coating/curing process, and the exact specification of the goop you want to spray and maybe I can help. As you can tell, coating my own papers is something I have never thought of doing, but (gasp) I'm very familiar with the digital end of things and very up on my printer repair skills.

Photo Engineer
12-28-2006, 08:38 PM
Greg;

The 'goop' has to be between 90 and 110 deg F, and can be just about any viscosity you want from thick to thin, as long as you coat the required amount of silver per unit area.

It can be made to be as thick as the current inks, but would have to be hot as above.

The paper would have to absorb the liquid, or it would have to be somehow kept flat to dry.

PE

Greg_E
12-28-2006, 11:22 PM
Keeping flat would be easy for the Epson 3000, but I don't know if you could keep the temp up to 110 while it flies through the air before it hits the paper. You might have to build a heat box so that the air temperature is up at 90-110 or hotter, and there could be some problems with the heads at this temp, but it's kind of unlikely to be a problem. You may want to pre-heat the paper too, but that might be easy with some of the electric heaters on the market. Just run it over a heater bar as it unspools from the roll before it goes into the heater box.

What solvents are used in this process? Is it just water or something more volitile?

I wonder what it would take to get a chilled bar on the output of the printer to rapidcure the paper?

The required silver per unit area may be much harder to obtain with the very thin viscosity needed to spray this. The viscosity of modern pigment inkjet inks for Epson printers is only slightly thicker than water, and I do mean slightly. Wish I remembered the actual value but probably only .05 thicker, safe to say the same as water.

Would it be easier to make an automated blade coating machine that would take roll paper or large sheets? Seems like it should work similar to the way ink is transferred from the well to the press rollers on a printing press. Maybe a hybrid where the thicker goop is pumped through spray nozzels in a constant stream, then a blade to smooth the goop into a uniform layer. Then a rapid dry section near the output of the machine. You could precisely regulate the amount of sprayed goop so that there was minimal waste coming off the sides of the blade. If you heated the spray nozzels, and the rollers, and maybe the paper, this seems like it would be a better design. And yes I know I am probably reinventing the paper coating machines that (may) still be used today. I think this is a more viable machine for this task.

Is this an all dark process, or can it be in light until the goop cures/dries? What about IR and near IR light? A radiant heater might speed up the process so that it is a dry to dry process, else you might need to use the contact heaters to rapid dry the paper.

htmlguru4242
12-28-2006, 11:48 PM
Interesting Idea.

And Greg, it would have to be dark throughout the process. The light that you could use would depend on the color sensitivity and speed of the emulsion. Long wave IR light (heat) would probably be ok, unless of course its an IR emulsion.

Photo Engineer
12-29-2006, 09:15 AM
Interestingly enough, when Tony Perez (CEO at Kodak and former HP person) first saw a Kodak coating machine, he likened it to a huge inkjet printer. "Except for running in the dark".

PE

jgjbowen
12-29-2006, 10:33 AM
The 'goop' has to be between 90 and 110 deg F

PE

OK so that leaves Rochester out of the equation, but we could do this on the sidewalk in say.....Phoenix. Just send that $1,000,000 R&D check my way....

Very interesting idea..

Greg_E
12-29-2006, 04:56 PM
You can do the same task with jet technology, you just need the special industrial jets. There're out there, just very expensive.

There might be a spray coating head that would make this easier, then all you need is a pump. If you really want to pursue this, I would suggest looking for spray coating technology. I don't think the common inkjet printer will be the answer, at least not with a single pass. A spray with a trailing blade seems like the best option, especially if you use a goop that can be exposed to a safelight so that you can monitor the process until it is perfected.

Sean
12-29-2006, 06:20 PM
You can do the same task with jet technology, you just need the special industrial jets. There're out there, just very expensive.

There might be a spray coating head that would make this easier, then all you need is a pump. If you really want to pursue this, I would suggest looking for spray coating technology. I don't think the common inkjet printer will be the answer, at least not with a single pass. A spray with a trailing blade seems like the best option, especially if you use a goop that can be exposed to a safelight so that you can monitor the process until it is perfected.

The trailing blade would = mess. My aim is to have a machine that can be used exactly like an inkjet printer but making coatings with virtually no mess or cleanup. You would buy an emulsion canister or make a batch of emulsion, fill the canister, clamp the canister into the device then have the nossles do a coating in a way that is a perfect uniform coat that's repeatable, etc.