Inkedibles cartridges are refillable. They also come preconfigured with two "ports" or "holes". Both of these ports are sealed in transit, but 1 of them needs to be opened before the cartridge is inserted into the printer. The hole that needs to be opened (exposed to air) is the breather hole, and is shown in the attached diagram in the case of Inkedibles cartridges for Epson. If this hole is not opened, ink cannot flow in the cartridge, and ink therefore wont come out onto the page - resulting in a scenario in which the printer goes through the motion of printing, paper comes out of the printer, but little/no printing is actually done to the paper.
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