A Constant Pressure CIS like reported on by Narmenia

[canonfodder]

Narmenia is having some problem with his printer and CIS. What I am reporting here concerns the particular commercial CIS which he is using.

This CIS is quite interesting in that someone has figured out how to use a Marriottes Bottle in a system which will definitely provide a constant ink pressure to the printhead. There will be some influence of barometric pressure changes on this systems ink level, but it is probably not bad enough to cause trouble.

I see a flaw in the application of this CIS in that, with the recommended setup, a much greater negative pressure is provided than is really needed to make a Pixma printer happy.

The Pixma Printer such as an iP4200 or iP4300 does want a negative pressure at the printhead input. The sponge in the OEM CLI-8 cartridge provides that negative pressure. A CIS does not have to have a sponge in the cartridge, but it does have to provide an appropriate negative pressure. The magnitude of the negative pressure doesn't have to be constant, but that can help, for if it is constant, it can also be set at or near the lowest amount that is satisfactory, resulting in less work for the printhead pumping action and less stress on the cartridge-to-printhead seal. A reduction of the negative pressure is done by simply raising the ink tanks, placing them on a suitable block of wood or a book or two.

I see this same CIS system for sale on eBay, being sold from Australia. The price is about $128 US for the CIS filled with German ink and shipped to the USA. That's about twice the cost of the simple systems that come from China. I have inquired of the Australian company if they would sell the CIS empty of ink.

 

[leo8088]

Canonfodder, the negative pressure term you are using is actually the capillarity power of the sponge in witholding ink. This capillarity power is affected by the vent of the cartridge and by how ink is dried out in the emptied portion of the sponge in a standard sponged ink cartridge. This ink witholding force is critical to the print head as you have pointed out many times. I would like to add a comment regarding this.

After confirming with a friend who was an engineer at HP but now in a startup inkjet specialty ink company, I feel that this is something all Canon printer owners, especially who use a CISS, should be aware of.

When this ink witholding force is not enough ink will leak out from the print head nozzles. When it is too much the print head will starve of ink. Well, this is easy to understand and it has been seen quite often in CISS units. One of the solution has been using adjustable height setup to elevate ink bottles trying to achieve a proper ink witholding force, or negative pressure as you call it. However, what is not discussed here is when the print head is starving of ink it will boil the ink in the nozzles. The nozzles are so tiny. Boiling ink in tiny nozzles can be very damaging to the print head. It basically vaporizes the ink and leaves ink solid to be stuck in the nozzles. You can imagine leaving a print head unprotected to dry out in air. The only difference is one takes time to let the ink drying out and the other dries the ink almost instantly.

From what I was told, this reveals that ink's boiling point is one of the requirements in formulating inkjet ink. Many massively produced pre-filled ink cartriges contain diluted ink by unknown manufacturers who want to make a few more bucks by diluting ink which may have been good quality to begin with. As a reult the boiling point of the ink is reduced. This explains why many after market pre-filled ink cartridges are found to cause print head cloggings.

I tried a cheap CISS made in China on an ip6000. It did not take too long before I began to observe the ink boiling occuring in my print head. I realized that unless the CISS is safeproof to provide a proper and uniterrupted ink witholding force to feed correct amount of ink to the print head the print head will be under risk of damage.

I am not trying to say CISS will not work. I am trying to point out that there is always a risk of print head damage if a CISS fails to feed ink properly, which is a constant struggle of many CISS units discussed from time to time. Now I am sure your mission will be how to make a CISS that is safeproof (or almost safeproof) in feeding ink to the print head. Then it will be almost perfect to use CISS on Canon printers.

 

[narmenia]

btw i have a canon ip3000 on the same CIS as canonfodder mentioned.
running for about a year. (i was doing about 2 years on manual refilling before using CIS)

printhead is still the one that came with the printer.
i've changed 2 cartridges on the CIS (my supplier sells extra spare carts)
- 1 yellow (due to bubbles on tjhe sponge)
- 1 cyan (degradation of sponge?)

Everything is Fine except when printing photos the first part of the paper gets dirty with black ink (i'm clueless)

 

[websnail]

Everything is Fine except when printing photos the first part of the paper gets dirty with black ink (i'm clueless)

A photo of the printout would probably be useful there...

Is it streaky or just spotted with black ink?

The former would indicate tubing stroking the paper, the latter would indicate the ink quality may be poor on the black and/or the printhead is leaking a small amount of ink that's collecting under the printhead.