Canon ip4200 CIS - returning to the fray!

[canonfodder]

Websnail,

Concerning the results of "Ink Too High", and now thinking of the problem I will refer to as "Leaking Seals" for the seals at the cart-to-print head junction:

I know what the printout of a CIS with "Ink Too High" looks like. I have been generating that condition intentionally and taking measurements. I will report later with details and scans of the printouts. I do nozzle checks, but have a bit more faith in the MIS provided PURGE pictures for real testing.

?1. In your experience, does the printout with a "Leaking Seal" look similar to that with "Ink Too High", or can you say it is distinctly different?

I ask this because I have not been able to make my iP4200 demonstrate a "Leaking Seal". In attempts to cause a negative pressure at the seals, I have had the CIS ink low, but not very low. Perhaps I should try even lower. Perhaps I am just lucky, and have a printer that has exceptionally good seals.

?2. Is there any possibility at all that the "Leaking Seal" problem is a mis-identification of "Ink To High"?

I know that this seems unlikely, considering all those who have worked to fix the "Leaking Seal" problem, but:

?3. What do you think?

 

[websnail]

Concerning the results of "Ink Too High", and now thinking of the problem I will refer to as "Leaking Seals" for the seals at the cart-to-print head junction:

I know what the printout of a CIS with "Ink Too High" looks like. I have been generating that condition intentionally and taking measurements. I will report later with details and scans of the printouts. I do nozzle checks, but have a bit more faith in the MIS provided PURGE pictures for real testing.

The latter printout will give you a much better idea of what's going on... nozzle checks don't help at all in the ink-too-high instance.

?1. In your experience, does the printout with a "Leaking Seal" look similar to that with "Ink Too High", or can you say it is distinctly different?

The printout itself is not the indicator it's a small bubble of air in the tubing that provides the most help. If you have a leak it will fall back towards the reservoir or simply not move at all (when printing).. Getting a small bubble in is simple enough.

I ask this because I have not been able to make my iP4200 demonstrate a "Leaking Seal". In attempts to cause a negative pressure at the seals, I have had the CIS ink low, but not very low. Perhaps I should try even lower. Perhaps I am just lucky, and have a printer that has exceptionally good seals.

Quite possibly... I wouldn't recommending forcing the issue... As I said printouts aren't helpful but air direction is.

?2. Is there any possibility at all that the "Leaking Seal" problem is a mis-identification of "Ink To High"?

I know that this seems unlikely, considering all those who have worked to fix the "Leaking Seal" problem, but:

Oh definitely not... there's been plenty of times I've had that problem and the solution has always been to pop a small bit of silicon grommet in between the rubber grommet and the cartridge. So long as everything is clean and the cartridge hasn't got a big dent in the out-port that's letting air out the side it should work reasonably well. The trick though is to add grommets for ALL cartridges if you add for one. Doing individual grommets tends to unbalance things in my experience.

 

[ocular]

My reading suggests that that maybe the canon grommets in the newer chipped cartridges are less likely to leak than the earlier canon printers ( no personal experience of this).

One variation to using silicon washers to secure the seal between the grommets and the cartridges is to use O rings. Sam Cahir from Rihac gave me the hint that they had tried this. I have bought an assortment of sizes of O rings. The underneath of the grommets have a 'skirt" that is splayed out against the floor of the print head when the ink cartridge compresses the grommet. As the grommet ages the skirt loses it's firmness and the gromment effectively becomes thinner, thus the need for a thin silastic seal. The correct size O Ring can be placed over the skirt to make it less squashable and thus offer more force to seal between surfaces.

This is all just imagination, but will try it soon.

 

[websnail]

The correct size O Ring can be placed over the skirt to make it less squashable and thus offer more force to seal between surfaces.

This is all just imagination, but will try it soon.

Sadly the o'ring that fits around the skirt on printers like the 4200, 4300, etc... have this shallower grommet which in itself isn't a problem but they also have less clearance around the outside of the skirt so you'll be hard pressed to find an O'ring that'll fit around it properly.

I've not examined this in massive detail as yet but my initial foray didn't provide much hope... The iP4000 and iX4000 use a much deeper skirt and weirdly have greater spare around the skirt so it's less of an issue..

 

[websnail]

Well I just don't know what to make of all of this but I do know this is seriously p*ssing me off.

I've had a bunch of printers working just fine and then about a month ago the magenta problem started re-appearing again and even taking into account the issues of over-pressure, and everything else I've learned over the past 2 years I can't figure out wtf is going on.

Ironic really as I'd just about given up on the HP K550 and L7680 I was working with and now I've solved that only to have my trusty Canons all screw me around yet again.

Frustrating really isn't the right word to describe my current thoughts on the subject.

 

[websnail]

Interestingly as a follow up the printhead is exhibiting other problems now, specifically I can't get it to work properly with a set of virgin OEM carts.

The key factor now seems to be the rubber grommets and whilst I have had a thin 1mm silicon seal between each grommet and cartridge I'm not entirely sure that that accounts for all the issues I've been seeing. Weird doesn't cover it.. but it does seem as if the printhead is getting damaged in some way. The hard part is working out how exactly it's happening and the best plan of attack for resolving it.

 

[websnail]

... and just because I can (thanks to an order of new printheads I recieved this week) I decided to bite the bullet and start over with a new printhead and a much tweaked CIS kit that had the following key-points,

1. The fittings and tubing were directing ink into the spongeless tank part of the cartridge
2. The cartridges have been vented such that there is air in the top part of the sponged cartridge segment (not overfull ink)
3. I allowed a 25% air buffer in the top of the spongeless cartridge segment
4. The tubing is approx 2mm inner diameter (ID) tygon brand (bit big but it does ok until I can get something better)
5. NO silicon seals (not required at this stage it seems)
6. Ink levels lower than the printhead by approx 2inches

As near as I can tell this particular setup works by:
- allowing a buffer of air to absorb the effects of ink being used during each pass
- not overloading the sponge above the printhead and thus avoiding forcing ink into it (over-pressure again)
- allowing the ink to refill in a more gradual fashion instead of adopting a sort of "sloshing" effect in the tubes and cartridge


At a guess, and this is a guess, it should be possible to get a similar effect if you glue in the fitting/connector above the sponge but you'd still need to allow an air buffer over the sponge so any ink replacing the ink would wick into the sponge from above. What I find "odd" is that some printheads seem more than capable of handling additional pressure while others are highly sensitive and crap out quickly.


One interesting thing I've picked up though and that's the pigment black shows signs of banding even in a printhead that is brand new and has OEM cartridges (no CIS) installed, despite a head alignment. I'm starting to believe that in some cases the actual printer body itself could induce some faults but I've no idea why or how.

Anyhoo... I'll be building another of these CIS kits using the same techniques above and seeing how it goes in an iP4300 which I got off ebay recently as a refurb. We'll see how that goes in a few days time.

 

[Grandad35]

1. The fittings and tubing were directing ink into the spongeless tank part of the cartridge
2. The cartridges have been vented such that there is air in the top part of the sponged cartridge segment (not overfull ink)
3. I allowed a 25% air buffer in the top of the spongeless cartridge segment
4. The tubing is approx 2mm inner diameter (ID) tygon brand (bit big but it does ok until I can get something better)
5. NO silicon seals (not required at this stage it seems)
6. Ink levels lower than the printhead by approx 2inches

As near as I can tell this particular setup works by:
- allowing a buffer of air to absorb the effects of ink being used during each pass
- not overloading the sponge above the printhead and thus avoiding forcing ink into it (over-pressure again)
- allowing the ink to refill in a more gradual fashion instead of adopting a sort of "sloshing" effect in the tubes and cartridge

I don't use a CIS (and have never seen one in operation), but can't venting the sponge chamber allow the cart to work as a "regular" cart by replacing ink that is drawn from the spongeless chamber with air instead of pulling ink from the CIS? I suppose that there is an ink level in the external bottles that perfectly sets the suction pressure such that ink is drawn from the spongeless chamber without air being drawn back to replace it, but this seems like a very touchy setup with a narrow operating window.

 

[websnail]

I don't use a CIS (and have never seen one in operation), but can't venting the sponge chamber allow the cart to work as a "regular" cart by replacing ink that is drawn from the spongeless chamber with air instead of pulling ink from the CIS?

Whoops... my mistake, you're right that such a setup with a vent left in place would be a very delicate operation (and nigh on impossible to achieve)..

So to clarify, what I mean't by venting them was to open the cartridge up over the sponge section, allowing ink levels to stabilise in that part before re-sealing the vent hole again. There's no openings to air left so the cartridge will still draw ink into the cartridge to replace the ink already used (in the tank/spongeless section). The key thing is that there's the "normal" amount of ink in the sponged section as well as a healthy 25% air buffer/bubble in the tank/spongeless section as well. Because of gravity this air should remain in the cartridge ad infinitum and help smooth out the stresses caused by tube flexing and the jetting processes themselves allowing the ink to flow smoothly.

 

[mikling]

Here's something that might be of consideration. What happens to the enclosed volume of the tubes as they flex back and forth. Is the flexing related to the banding in black? If the volume decreases and then increases, you've made yourself a nice little pump or something that constantly fluctuates pressure.
The enclosed volume must vary because given a fixed circumference, we can maintain the circumference but decrease the volume as we go from a circle to an ellipse and to the limit..zero volume if we flatten the ellipse. This is what happens to the tube as it bends especially if the diameter is large as the larger diameter tubes will undergo more strain for a given curvature and tend to flatten into an elliptical cross section as the curvature decreases.

Just a thought.