TUBULAR WRITING INSTRUMENT WITH SUCTION VENT

摘要

A writing or drawing instrument wherein a housing (1), is provided with a writing point (2) and a writing fluid reservoir (3) within an interior space of the housing. A capillary pressure equalization system (5), that connects the reservoir with the ambient air, has a sensor (7) therein for reacting to the level of writing fluid (4) therein. A suction pump (11, 12) is connected with the writing fluid reservoir (3) through a semi-permeable membrane (10) which lets air through and is impermeable for writing fluid (4). The suction pump (11, 12) is activated by the sensor (7) in response to a level of writing fluid (4) in the pressure equalization system, and aspirates air from the reservoir so as to quickly reduce an overpressure condition.