Hi

With reluctance I am posting this.

This affects HP 21/27/56/ HP 92/94/96/98 HP 74/60/901 and maybe others.

I don't want what I am saying to be lost on the chemicals...I am not a scientist.

Also it may not effect you yet...but it's coming.

First, 2 chemicals...

1) Cyanoacrylate (Crazy Glue) (super glue). When I refer to Crazy Glue, I mean a derivative of Crazy Glue. Just that Crazy Glue is easier.

Here is some information about Cyanoacrylate...

(SEE THIS)

One of the key things about Cyanoacrylate is the following...

"Generally, cyanoacrylate is an acrylic resin which rapidly polymerises in the presence of water (specifically hydroxide ions), forming long, strong chains, joining the bonded surfaces together. Because the presence of moisture causes the glue to set, exposure to moisture in the air can cause a tube or bottle of glue to become unusable over time. To prevent an opened container of glue from setting before use, it must be stored in an airtight jar or bottle with a package of silica gel."

2) Acetone, again a derivative of acetone. Also looking at nitromethane.

Now looking at these 2 chemicals. When mixed together, the Crazy Glue will disperse within the Acetone, without the Crazy Glue hardening. That is because Acetone is a solvent to Crazy Glue. There are surfactants made by Dow that will disperse Acetone...and those surfactants are meant for inkjet printing.

HP's black printer cartridges have ink that has been recently re-formulated. Looking at the cartridges we see several issues...

1) Lack of proper ink flowing out of the print head. When you footprint the cartridge...no ink or not the proper amount of ink shows on the paper towel.

The CG has hardened on the print head with in the inkwell. Also the filter in affected, leading to ink starvation.

2) Fill volumes. Harder to reach the fill volume. The sponge appears to have become less absorbent.

The CG has been dispersed throughout the cartridge and the sponge. Causing the sponge to become “crisp” and less absorbent.

3) Print test results are not "crisp". The grid pattern is off or jagged. Not necessarily missing segments...but the grid is jagged.

Again the CG has hardened on the inside of the print head. When CG hardens it forms an “acrylic” type substance. This substance also hardens in the nozzles, causing irregularities in the outputted prints.

My opinion...

HP has changed the ink used in these cartridges. The ink now contains a chemical similar to Crazy Glue (cyanoacrylate), dispersed in a chemical similar to Acetone, and other chemicals to maintain stability.

Normal CG would harden in ink...but mixed with a chemical similar to Acetone, it would not.

CG and Acetone would not affect ink printouts, since Acetone evaporated as fast or faster that alcohol. And since the Acetone evaporated, the water in the ink would just as quickly harden the cyanoacrylate. In affect producing a more resistant printed image, because of the acrylic resins in cyanoacrylate.

The more I look into this the more it makes sense.