Refill ink cartridge of a printer with hydrogel.

[Hernesto]

In order to continue the medicine research project which I
cooperate, I need to know the follows things:

1- How does it work the system that detects a ink cartdrige (of a stndard printer)
is empty?, what is the mechanism?.

2- How is it possible to "cheat" on detector system to refill ink cartdrige with
hydrogel (instead ink)? (If you can explain me how with ink,
it would be worth to me as well).

I am trying to understand the mechanism that detects ink cartdrige is empty, but if
anybody could explain me how does she/he to refill a empty cartdrige,
even if she/he doesnt know the reason very good, It would be worth as well and I would be
very gratefull.

Ah, and of course any idea or suggestion to explain this It would be wellcome.

Right now I am working with two printers models, HP Deskjet 3050 (HP ink cartdridge = 301)
and HP Deskjet 6940.

If the explanation would be fine for these two types of printers the better!, otherwise it is ok
to read the explanation for other type.

Cheers and thanks in advance.

 

[turbguy]

Welcome to this forum. I may not give you a complete response to your questions, so hopefully others will also respond.

Various methods are used to detect when an ink cartridge ("cart") is empty. Most "popular" is a software-based counter in the printers firmware which keep track of ink used and declares the cart empty when a certain count is reached. These are typically very conservative and some usable ink remains in an "empty" cart.

Canon (and perhaps other manufacturers) also uses an optical prism in the bottom on the ink reservoir that refracts light from an LED to a sensor that scans the carts as they sweep back and forth during printing. When the ink level in the reservoir drops below the prism, light then refracts to the sensor and the cart is declared empty by this direct measurement.

Manufacturers sell printers at a highly discounted price (probably WELL below the cost of manufacture and distribution) in order to sell replacement ink carts at VERY highly inflated prices. Replacement ink bought this way can cost well over $2000 US per liter! This is know as "the razor blade model" of marketing. Cart Refillers (like most of us that use this forum) buy ink in bulk (typically 100 ml for about $10 US) and break the manufacturer's marketing model in order to enjoy almost "free" printing.

About 10 years ago, manufacturers began using "electronic counter measures" to attempt to prevent successful refilling. They began attaching an electronic circuit (a chip) to each cart to communicate with the printer that a previously empty cart was being inserted into the printer again. The printer then would refuse to use the refilled cart. Refilling suppliers then hacked this system and developed small cheap devices that would effectively "reset" the chip to report the refilled cart full. Then the manufacturers installed wetness detectors in the chips to detect when the ink reservoir was actually dry and burned out the chip to prevent resetting. Then refill suppliers hacked that system and began supplying replacement chips that bypassed that scheme and allowed automatic resetting upon cart removal from the printer. This cat-and-mouse game continues today!

Refilling effectively is a scheme to inject more ink into the empty cart's reservoir so it can be successfully used further. After all, the manufacturer got ink in the cart, somehow! Some cart designs are easy to refill, some (like many HP's) are not. The technique for refilling varies with the cart design.

That said, refill ink must match the physical properties of the original ink closely. This properties include, viscosity, boiling point, and particle size. Most ink flow from a desktop printer cart to a print head is by very low pressure (less than 3 cm water column). If you cannot get your intended ink to flow adequately through the cart and printhead freely, you will not be successful.

Wayne

 

[panos]

Cheating the system is not difficult since printers don't check physical or chemical properties of the ink (they just clog instead) but rather use electronics to check out ink usage and dates. However, I don't think inkjet nozzles can make bubbles out of hydrogel. Perhaps piezo inkjets (Epson) may be able to push hydrogel out.

Just an idea: use a dot-matrix with the ribbon cleaned out and then soaked in hydro-gel.

 

[Hernesto]

Thank you very much Wayne, your reply is very complet and usefull.

Thank you very much to you as well panos, your suggestions are very interesting,
I will consider your idea.