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AssigneeRotring-Werke Riepe KG
InventorsWalter Jozat, Steffen Wunsche, Ronald Broers, Thomas Hentze, Horst Eising
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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.
In a writing or drawing instrument comprising a housing provided with a writing point and comprising a writing fluid reservoir within an interior space of the housing, wherein the reservoir is connected to ambient air via a capillary pressure equalization system, the improvement comprising a sensor (7) adapted to react to the presence of writing fluid (4) that is provided in a chamber of the capillary pressure equalization system (5), and a suction pump (11, 12) that is connected with the writing fluid reservoir (3) through a semipermeable membrane (10) which lets air through the membrane but is impermeable to writing fluid (4), wherein when the sensor (7) senses a certain level of writing fluid (4) in the capillary pressure equalization system, a signal is sent to a circuit means that activates the suction pump (11, 12) so as to reduce the level of writing fluid in the capillary pressure equalization system.
Dependencies are inferred from the claim text.