Canon CIS's something to watch out for

[websnail]

The issue of the rubber seal not being quite up to scratch for the pixma printers is pretty much a given now but I thought I'd pass on another nugget I learned after literally months of head scratching, trying to figure out WTF has being stopping my Yellow flow on various Pixma printers lately.

I was leaning heavily towards the issue being an ink one which in some ways it is but the main culprit turns out to have been poor contact between the cartridge sponge and the ink receiver in the printhead.

I'm guessing here but I think that there was a small gap between the port and the sponge and instead of feeding into the port, ink was wicking down the cartridge exit port sides and around the port ending up with ink under the grommet (rubber, silicon, it didn't matter). So instead of printing the whole thing was suffering from vaccum and being a pain in the proverbial a**.

My solution has been to place a wedge of tubing or cardboard between the top of the cartridge and the printhead locking bar (being careful not to overdo it!) and that seems to push the cartridge that little bit further down so that contact is made properly and the yellow prints.

So far this is untested on anything other than my MP830 but I have at least 2 other printers exhibiting the same issue and I'll be testing those tomorrow. Either way it'd be interesting to see if my theory is right.. Anyone care to put some science behind my WAG (Wild Assed Guessing)

 

[canonfodder]

Websnail,

Your WAG and some thoughtful logic can turn into a scientific diagnosis with evidence to support it. It is always preferable to have some concurring independant information, from another persons trials or even from second and third printers of your own, but you seem well on the way to pinning down the problem.

If you were to assume that there is no mechanical shortcoming in the cart and how it fits the head assembly, you might look to the sponge as a source of variation. Grandad35 showed a bit of displaced sponge information in his post http://www.nifty-stuff.com/docs/canon-BCI-6-cartridges.php . He was dealing with a displacement caused by purging water flow, but other things could do something similar. I wonder if too much finger pressure on top of the cartridge while installing it could move the sponge up a bit and cause a problem?

You did indicate by your post location and title that you speak of a printer with a CIS installed. Are the carts made of modified OEM carts in a self-build system, or are they something different supplied with a manufactured CIS?

Canonfodder

 

[websnail]

Your WAG and some thoughtful logic can turn into a scientific diagnosis with evidence to support it. It is always preferable to have some concurring independant information, from another persons trials or even from second and third printers of your own, but you seem well on the way to pinning down the problem.

There have been some reports of similar issues on stevesforums from one particular user and he's using a similar setup to me. But no confirmation on cause.

If you were to assume that there is no mechanical shortcoming in the cart and how it fits the head assembly

Well, the primary colour that I hit this problem with is the yellow. I thought I'd resolved it when I swapped the ink for an old batch but it reappeared in one printer before the holidays and again later when I got back after New Year.

you might look to the sponge as a source of variation. Grandad35 showed a bit of displaced sponge information in his post http://www.nifty-stuff.com/docs/canon-BCI-6-cartridges.php . He was dealing with a displacement caused by purging water flow, but other things could do something similar. I wonder if too much finger pressure on top of the cartridge while installing it could move the sponge up a bit and cause a problem?

Unlikely given that I've had the same issue with all the yellow cartridges and not with others in over 7 printers. If it was a random selection of cartridges I think I'd be more inclined to agree. Also worth noting that I did check the cartridge foam placement as I had remembered it being an issue in the past (in Grandad's posts) but it doesn't appear to be related.

You did indicate by your post location and title that you speak of a printer with a CIS installed. Are the carts made of modified OEM carts in a self-build system, or are they something different supplied with a manufactured CIS?

These are Canon OEM carts that have been converted as parts of a CIS that I've built myself. There's a variety of fittings, tubing ID (inner diameter), ink is constant (ie: it's Image Specialists) but different batches showed slightly different results.. also there are a variety of grommet with originals left or whole replacements in silicon or slim silicon overlays..

I've some more testing to do today with the other problem printers but I expect to be able to confirm the solution as there really is nothing else left that it could be now

 

[jtl]

Do you think this is only a problem if you are using a CIS or would it also affect all oem carts and Pixma print heads? If it affects all non CIS units you would think there would be more complaints and a Canon recall.

 

[mikling]

In post #23 of this thread
http://www.nifty-stuff.com/forum/viewtopic.php?id=1635
your problem is possibly this issue.

The pressures or negative pressures generated with a head cleaning which the printer automatically always performs full or near empty is different from that with a standard cartridge. Why? the venting restriction is just that of air coming through the vent as opposed to ink coming through the very thin and long ink feed lines.

 

[websnail]

In post #23 of this thread
http://www.nifty-stuff.com/forum/viewtopic.php?id=1635
your problem is possibly this issue.

The pressures or negative pressures generated with a head cleaning which the printer automatically always performs full or near empty is different from that with a standard cartridge. Why? the venting restriction is just that of air coming through the vent as opposed to ink coming through the very thin and long ink feed lines.

Maybe but the fact that it only actually happens on one ink type is a bit odd as the tubing, venting, etc.. is all the same through all colours and cartridges.

Of course it may be that the yellow being central, suffers from the most vaccum pressure... Either way the solution I've suggested does seem to work.

 

[websnail]

This is related to this issue although it's not so much focused on the yellow now..

I've been going through the printers that were hitting problems with the ink feed and found that the solid silicon replacement grommets are actually causing more problems than they're solving. The ones I sourced from Hong Kong (via the iP4200 CIS manufacturer I've yet to review) were about 0.75mm - 1mm thicker than the original grommets and this pushes the cartridges further away from the ink post. This in turn has had the same sort of effect noted above with the yellow..

Unfortunately, I don't have the right size tools to create the alternative thin grommets now being provided with Canon CIS kits (although I do have the silicon - 0.5mm) but I did find a workaround in that providing a little extra pressure between the cartridge top and the printhead retaining lever will push the cartridge down a little further an effect a slightly better seal with the original rubber grommet.

Worth noting that I've been able to affect a solution by putting thin grommets over the PhotoK, Y, C, M and then applying pressure above the yellow and Pigment K to get it to work. A trial where I put a wedge in across all the cartridge tops resulted in the printer reporting an unspecified error.

 

[jackson]

but I did find a workaround in that providing a little extra pressure between the cartridge top and the printhead retaining lever will push the cartridge down a little further an effect a slightly better seal with the original rubber grommet.

Is this solution peculiar to CIS kits or would it have utility for regular carts?
In my own setup I notice that the IP3000 needs less tinkering after cartridge changes than the IP5000 to effect a good nozzle check.
No difference betwen OEM refills and Hobbicolors in the above case.

 

[websnail]

Is this solution peculiar to CIS kits or would it have utility for regular carts?

It shouldn't be required for a regular (non-CIS) cartridge as there's not the same need for air-tight seals...

Chances are if you're seeing this sort of ink starvation in your scenario it's because the sponge has moved during a refill or something similar.

You're better off asking people like Grandad, and other knowledgeable types about this as refilling or standard carts are more their area of expertise.

 

[canonfodder]

Well, it looks like I have something to really be cautious about when I receive and install my CIS coming from Hong Kong. They do provide the alternative seals talked about here. They have an explanation for needing and using them, and would charge $5 or so if you just wanted to order them alone.

So an airtight seal is the goal, but if the seal is too thick or too hard, it may keep the dummy cartridge from seating properly and thus making contact to the wick which feeds the head.

One thing I don't know yet is this: Does the dummy cart have any filter-like thing in its exit port?

Websnail, you have your untested HongKong CIS. Do you see filters in the dummy carts? Is there nothing there, so that the ink can come right out?

That would make things a lot different than the self-build CIS which uses OEM carts with sponge AND exit port filters. Those exit port filters could hinder things if they don't make contact.