Ripr wrote:
After considering your comments above and researching some more, I would like to explore building a DIY CIS for the HP B8850. Your input is sought as a Guru of CIS.
LOL ..
CIS Guru... That's a new one but thanks
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First, you allude to a resetter for the HP 38 cartridge chips. Can you offer a source that explains the mechanism provided by the HP 38 on-cartridge chips? Is it only an ink level gauge or does it also have usage recordkeeping and triggers replace messages when certain counts are reached?
I don't know about a resetter (ie: something that resets the original chips) but I do have a source for Auto-reset chips for this model. Not entirely sure how reliable they are though.
The chip is not the only ink gauge though which is the important reason why many of the other CIS systems are a bit cr*p. The OEM cartridges has a rubber bulb on the base which the printer piston (one for each colour) pushes against. This process somehow has a pressure sensor which helps it determine when the cartridge is empty of ink or has a large amount of air in it.
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What logic condition must be achieved for the printer to believe there is always ink available in the cartridge – even though it is being refilled from a reservoir?
To summarise... a "valid" ARC or OEM chip... and a cartridge that either fools or mimics the OEM cartridge.
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I will purchase a HP 38 cartridge for purposes of dissection – you had previously provided several (5) images of a cartridge you took apart (forgot to bookmark the page) (don’t remember the brand – but it contained a baggy) and I would assume the HP 38 is fairly similar.
No need... the HP38 cartridges are the exact same as HP10/11/88 and I think 23's as well... HP like the design so they've used it again and again.
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The key issues seem to be the need to:
- keep air bubbles out of the ink path
- keep the printer pump from pushing ink in the cartridge “ink bag” back up the feed tube running from the reservoir.
- either periodically or continuously “topping-off” the ink bag in the cartridge
If you use and abuse (ie: convert) an OEM cartridge you solve the last two problems thanks to the fact that you can feed the original cartridge via the filling port
(remove the chip holder and you'll see it).
The first problem is easy enough to fix by:
a) vacuum filling the cartridge when you prime it
b) allow it to fill and then tip the cartridge so you can draw off any air through the output nozzle
c) install the cartridge in the printer and then draw off another 10ml using a blunt needle in the nozzle that the printhead connects to in the printhead carriage.
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Reading thru a bunch of forums, it appears the meticulous planning and execution of the initial charging of the system is the key to an air bubble-free system. There is no quick fix.
Yup... You can really f*ck things up if you rush... (not that I've found out the hard way...
*ahem*)
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I would assume the placement of a check valve in the ink line between the reservoir and the cartridge would resolve the second issue.
The OEM cartridges have a one-way check valve in them so you can't force air or ink back into the cartridge once it's in the rubber bulb.
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The third issue is the nexus of a CIS system for this printer. Obviously, a gravity feed does not work because that would be too simple.
Bzzztt... wrong... if you use the OEM you can use a basic dip tube layout. A gravity feed is the system I have setup with my kits... With modified OEM cartridges you just need to have the ink levels a small amount above the cartridge levels.
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Examining images of "Commercial" CIS kits offered for this printer, if the illustration is not clipped, seem to include some manner of a mechanical pumping system for each color. How does one sense when to pump? If ink is costumed at different rates then replenishment will be needed at different intervals.
Would it be simpler to pressurize the reservoirs?
LOL... there's no mechanical pumping system in the CIS kits.. just an equalised pressure style reservoir which seems to be the one-size-fits-all approach to CIS kits which can work but isn't necessary so long as you take the lessons above into account.
[quote]Pass along your initial expert comments and then we’ll execute the next iteration.[/quote
That lot should give you a bit to go on with
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Printers: (Canon) MP500/830, MX700, iP4000/4200/4300/4500/5200, iX4000(A3) (Epson) C84/86, D88, CX6600, R285/800/1900 (HP) K550, K850, K5400, L7680