Air pressure regulating device for ink cartridges

摘要

An air pressure regulating device for ink cartridges that is not affected or interfered with by magnetic fields. In accordance with the invention a ventilating vent is settled inside the ink cartridge so that the inside region of the ink cartridge is open to the ambient air and at the same time this ventilating vent is also directed to a fixed seat. In the fixed seat a gas vent is settled to direct to the ink cartridge. On the outside region of the gas vent settled in the fixed seat a layer of elastic gastight material is covered such that it can be utilized to seal the gas vent to keep the ink cartridge sealed under ordinary conditions. When the pressure difference between the outside and inside regions of the ink cartridge reaches a critical value, the layer of the elastic gastight material is slightly pushed away so that a small quantity of air can flow into the ink cartridge to return the pressure to within a normal operating range.