US Patent 8096725 Writing implement comprising a device for venting the reservoir

A writing implement that includes an ink reservoir, a writing tip fluidically connected to the reservoir and through which the ink emerges during a use of the implement, and a reservoir-venting device that includes a cavity in communication with the reservoir and with an orifice open to the outside of the implement. The cavity is suitable for absorbing an overflow of ink, characterized in that the cavity is filled with separate grains having angles and sharp edges having dimensions that are significant compared with an apparent dimension d of the grains.