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#1: HP88 adaptation in a home made CIS Author: zunga,

Posted: Sun Aug 17, 2008 5:35 am
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Hi there.

I apologize for my poor english!

I've been experiencing a lot of trouble with the HP K550 and due to it's faulty behavior it made me lose 5 printheads all due to low ink pressure. The disappointment I had was such that it made me buy a new HP L7680 and put the K550 aside for a while.

After many hours on the web trying to figure out any solutions for this ink pressure issue on printers that use the HP88 cartdrige, i've ran into many posts that Martin published on a couple of foruns and so I could recongnize that somehow he has come around this issue by building himself a home made CIS kit using the original HP88 carts.

It was a very simple but also innovative idea to cut away those metallic bags and plug the CIS tubes directly in the cartdrige's ink intake located on the black-bulb pump. For me it was like the bright light in the end of the tunnel.

So before I resort to adapting my old HP88 carts I was really looking forward to hear from anyone who has tried this out about any results with this system he's come up with. I'm very anxious to know for sure if someone managed to solve the low-ink-pressure/burned-printhead problem because honestly, I can't afford to lose yet another printhead, this time with my brand new L7680.

So please, let me know what results you guys got with this idea. I'm very eager to try it out but I'm also concerned about damaging anything else.

Thank you all very much for your time and consideration.

#2: Re: HP88 adaptation in a home made CIS Author: Martin, Location: South Yorkshire, UK

Posted: Thu Sep 04, 2008 7:08 pm
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zunga wrote:
It was a very simple but also innovative idea to cut away those metallic bags and plug the CIS tubes directly in the cartdrige's ink intake located on the black-bulb pump. For me it was like the bright light in the end of the tunnel.

Oops... you probably missed that it didn't work too well and instead I resorted to a system that feeds ink into the cartridge via the filling port in the base of the cartridge (find once you remove the chip holder).

This is much more effective but a bit of a pain to glue in place.

Quote:
So before I resort to adapting my old HP88 carts I was really looking forward to hear from anyone who has tried this out about any results with this system he's come up with. I'm very anxious to know for sure if someone managed to solve the low-ink-pressure/burned-printhead problem because honestly, I can't afford to lose yet another printhead, this time with my brand new L7680.

So please, let me know what results you guys got with this idea. I'm very eager to try it out but I'm also concerned about damaging anything else.

Thank you all very much for your time and consideration.

Best I can think to suggest is consider using dyebase ink instead of pigment ink as this resolves quite a few problems straight away. The pigment ink is just not that great and tends to clog the printheads especially in warm/hot/dry environments.

#3: Author: zunga,

Posted: Sun Sep 07, 2008 12:46 am
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Thank you very much for replying!

So you think it's best to keep that little chrome bag inside the cartdrige instead of removing it and pluging tubes directly to the ink intake? I believed that the bag could pop or anything if the ink pressure inside it was too high. And what about air? Isn't there a big chance of retaining air inside those bags that i can't see, since that chrome won't let me see through it to check ink level?

I was thinking about removing that little black rubber ball and connecting the tubes with the "sockets" and those silicon rings placed around then (again, please don't notice my poor english), so I don't see how it could be difficult (unless i'm figuring it all out wrong lol)

At last, is it ok to inject dye based ink inside the printheads wich contain pigmented black ink? Is it ok to perform this mixture?

Thanks again!

#4: Author: Martin, Location: South Yorkshire, UK

Posted: Sun Sep 07, 2008 9:43 pm
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zunga wrote:
So you think it's best to keep that little chrome bag inside the cartdrige instead of removing it and pluging tubes directly to the ink intake? I believed that the bag could pop or anything if the ink pressure inside it was too high.

Those bags are quite strong so standard or even heavy fluid pressure caused by gravity shouldn't be a problem. The cartridge would flood the printer before the bag would go IMHO.

Quote:
And what about air? Isn't there a big chance of retaining air inside those bags that i can't see, since that chrome won't let me see through it to check ink level?

You'd need to vaccum fill the cartridge/bag and then draw off any air but the latter is easily done by installing the cartridge and then drawing ink through the ink receiver that the printhead plugs into in the printer itself. Air is definitely something to watch out for though so it's worth triple checking if you're not sure.

Quote:
I was thinking about removing that little black rubber ball and connecting the tubes with the "sockets" and those silicon rings placed around then (again, please don't notice my poor english), so I don't see how it could be difficult (unless i'm figuring it all out wrong lol)

It might work... I've had problems finding good glues.. You'd need a clean edge to the hole whatever happens to reduce potential leakage.

Quote:
At last, is it ok to inject dye based ink inside the printheads wich contain pigmented black ink? Is it ok to perform this mixture?

I've used dyebase ink in a printer at home and it worked ok so I've moved a trial unit to a school with high temps to see how that performs there. I would run through a lot of prints to purge any pigment ink in the head though to be on the safe side.

#5: Author: xiphmont, Location: Somerville, MA USA

Posted: Sat Mar 28, 2009 8:53 pm
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Martin wrote:

Quote:
I was thinking about removing that little black rubber ball and connecting the tubes with the "sockets" and those silicon rings placed around then (again, please don't notice my poor english), so I don't see how it could be difficult (unless i'm figuring it all out wrong lol)

It might work... I've had problems finding good glues.. You'd need a clean edge to the hole whatever happens to reduce potential leakage.

I'm currently building out a CIS for HP10/11 made with the original cartridges and they're the same materials. The inner frames are made of either PP or PE (all the ones I have are PP, but there's a tiny stencil that indicates they can be PE too). The dye inks at least are super 'creepy'; they get through the tiniest spaces and even along the sides of silicone plugs. Even the little black rubber ball appears to have let a little past on virtually all the HP11 carts I've opened up. Not much, but enough to have made me thought the bags themselves were leaking at first.

I drilled and tapped through the little square PP frames in the carts and attached 3-52/1/16"ID brass hose barbs to the top (they work nicely with the typically used 1/32"ID tubing too). Even tightened down and tapped slightly 'under-diameter', a little bit of dye gets past over time. If you got just the right silicone plugs and snip off the top of the ink port that would probably work, but personally, I'm not trusting any of this without glue. This printer is now a shade under 10 years old and I don't want to be messing with it for another 10 :-)

There are trustworthy glues for PP/PE, eg, Bondit 45 epoxy, which is designed for these plastics. They're pricey ($50-70 for 50ml) but probably not considering how much better it would work than a $50 chinese import CIS. I have some, I'm trying it out today, I'll report back in a few days once it's had its full cure time.

I agree with everything else Martin said, nothing to add.

Monty

#6: Author: Martin, Location: South Yorkshire, UK

Posted: Sun Mar 29, 2009 12:44 am
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Hi Monty,

Thanks for your insight... It's been a while since I reported back on this one so perhaps it's worth adding to your own input.

I too found the whole issue of ink leakage to be an absolute bane of my life. The thread locking solution I've found works reasonably well but it's not perfect by any stretch with some leaks getting through. As I said in the other thread on glues the real solution is a double action approach with hot glue as the top-off sealer. Still in development but working well.

The brass fitting approach is interesting but metal to plastic sounds like a bit of a challenge Smile

As to the inks... I can now confirm having fought with my attic based K5400, K8600 and L7680 that the pigment ink in the HP88 black a major pain in the backside. There's nothing wrong with the ink in these temps because the K850 I've got up here is working consistently without ANY clogging at all... I've already switched the K5400 to dyebase as of last week and my difficult school has had a K550 with dyebase in it now for 6 months and it's had no problems at all... Looking at the 13 K/Y printheads sitting in my box I wish I'd switched over long ago... It's not like the dyebase is more expensive!

#7: Author: xiphmont, Location: Somerville, MA USA

Posted: Sun Mar 29, 2009 6:22 am
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Martin wrote:

The brass fitting approach is interesting but metal to plastic sounds like a bit of a challenge :)

The only reason I'm using brass is that you can't get threaded plastic fittings that small. Plastic just isn't strong (or precise) enough. Brass is really the only option.

Metal to plastic isn't hard at all so long as the metal isn't expected to flex if the plastic does! Most good glues bond to metal great, the hard part is often getting as good a bond to the plastic on the other side, and that has nothing to do with the metal.

The other option would be a straight/unbarbed fitting in through the ink port at the bottom and it looks like a 2.8mm/.11"OD plastic elbow is perfect (not as rare as the measurement sounds. The two Chinese CISes I bought and discarded as crap before embarking on this plan use them). I went with a threaded fitting at the top as I guessed it would be stronger and easier to purge air with the inlet at the top instead of the bottom.

I've been taking a *ton* of pics, I'll start a new thread with it. I'm waiting for epoxy to cure to call the carts finished. Everything appears to have assembled and glued perfectly, I'll find out if it leaks in 48 hours ;-)

Monty

#8: Author: Martin, Location: South Yorkshire, UK

Posted: Sun Mar 29, 2009 10:07 pm
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xiphmont wrote:
The only reason I'm using brass is that you can't get threaded plastic fittings that small. Plastic just isn't strong (or precise) enough. Brass is really the only option.

You mean like this Smile

Quote:
Metal to plastic isn't hard at all so long as the metal isn't expected to flex if the plastic does! Most good glues bond to metal great, the hard part is often getting as good a bond to the plastic on the other side, and that has nothing to do with the metal.

Yeah, fair point and I wish I'd thought of that way back when...

Quote:
The other option would be a straight/unbarbed fitting in through the ink port at the bottom and it looks like a 2.8mm/.11"OD plastic elbow is perfect (not as rare as the measurement sounds. The two Chinese CISes I bought and discarded as crap before embarking on this plan use them). I went with a threaded fitting at the top as I guessed it would be stronger and easier to purge air with the inlet at the top instead of the bottom.

Yeah... I tried the straight in approach albeit with barbs and the issue was making the seal around it work.. Very difficult and eventually went with the fitting linked top.

Quote:
I've been taking a *ton* of pics, I'll start a new thread with it. I'm waiting for epoxy to cure to call the carts finished. Everything appears to have assembled and glued perfectly, I'll find out if it leaks in 48 hours

LOL... I saw the multitude of post notifications so I'm about to take a peek now...

#9: Author: xiphmont, Location: Somerville, MA USA

Posted: Sun Mar 29, 2009 10:33 pm
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Martin wrote:
xiphmont wrote:
The only reason I'm using brass is that you can't get threaded plastic fittings that small. Plastic just isn't strong (or precise) enough. Brass is really the only option.

You mean like this :)

Not quite. 10-32 in plastic is common, but that's more than 4x the size, twice as wide as the ink bag frame itself in an HP 10/11. It's even too large to thread into the ink port on the bottom. I wish 10-32 was an option, it would have been way easier to use. It might be perfect in the HP88, I have no idea.

Monty

#10: Author: Martin, Location: South Yorkshire, UK

Posted: Sun Mar 29, 2009 10:53 pm
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xiphmont wrote:
Martin wrote:
You mean like this

Not quite. 10-32 in plastic is common, but that's more than 4x the size, twice as wide as the ink bag frame itself in an HP 10/11. It's even too large to thread into the ink port on the bottom. I wish 10-32 was an option, it would have been way easier to use. It might be perfect in the HP88, I have no idea.

Ah... I catch your drift... I did give your top down approach a try once, by drilling a small hole and then using a different epoxy to glue a plastic straight-in fitting over the hole. As you can imagine it was a real hack and slash approach with mixed results.

The 10-32 does actually work really well if you go into the fill hole at the bottom, provided you drill the hole out slightly bigger to a depth of about 4mm down. Too far and you split the side of the smaller tube beneath. It does work though and I've got 8 kits in different schools using this approach. The glue issue was always the problem I hit the most though.

I'll get some pictures up when I get myself sorted out..

BTW.. the HP88 cartridge is exactly the same physically... it's just the ink/chip that's different... In fact that cartridge design is used in a lot of places.

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