If you could mention which printer model and cartridge it might be
easier to discuss this.
The types of inks used (and therefore the appropriate solvents) differs
considerably between model and brands of printers. Epson has about 6
different basic ink formulations (and subcategories among them).
The cartridge designs also vary tremendously, from ones with sponges or
batting, to ones with only a hole, to some with semi-permeable
membranes, to ones with mechanical spring loaded valves, etc.
As mentioned, the label on the type you are likely referring to, is
there to reduce evaporation and oxidation while still maintaining a
method to equalize pressure within the cartridge as it drains.
Art
If you are interested in issues surrounding e-waste,
I invite you to enter the discussion at my blog:
http://e-trashtalk.spaces.live.com/
species8350 wrote:
> Hi,
>
> A friend was filling his cartridge the other day and asked me the
> following questions.
>
> 'My cartridge has a small air vent.
>
> The instructions on the leaflet said "widen it, fill, then replace any
> labels below the vent".
>
> He said: 'since the vent was block by a label in the first place why
> leave it open now just because its bigger?
>
> I don't know.
>
> He asked me what I thought the head cleaning solvent was. My guess is
> that it was probably iso-propyl alcohol. But this is just a guess.
>
> Any thought on the above two questions?
>
> Thanks
>