Ink compensating chamber for scriber
AssigneeKoh-I-Noor Rapidograph, Inc.
InventorLasse Kuparinen
Life of this patent
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Abstract
A capillary writing pen of the type having an expansion or compensation chamber intermediate the ink reservoir and ambient air. The expansion chamber is improved such that inadvertent flowing of ink from the reservoir to the capillary pen tip due either to pressure or temperature changes is avoided. The interior wall of the expansion chamber is profiled as a contiguous series of transverse indentations which extend circumferentially about the tubular pen body to provide successive expansion areas for entrapment of air and constrictive areas where menisci of ink are formed. The forming of the menisci entraps air bubbles within the ink and, accordingly, provides increased resistance to capillary flow of ink.
Claims6
In a capillary writing pen of the type having an ink reservoir communicable with a writing tip, the improvement comprising:
- (A) an expansion chamber interconnecting the reservoir and ambient air as a capillary channel apart from the writing tip and having an inner and outer wall for the flow of ink;
- (i) said expansion chamber comprising at least two circumferentially extending and interconnecting chamber portions, each portion having an inner wall comprising contiguous indentations which extend axially such that, in cross-section, a triangular wave profile is defined with respect to the outer wall of said circumferentially extending chamber portions, said at least two chamber portions being interconnected, in the axial direction, by means of an axially aligned connecting channel, whereby said indentations define, within said capillary channel, successive areas of expansion and constriction, such that ambient air is entrapped in the areas of expansion and menisci of ink are formed in the areas of constriction, and perpendicularly to the flow of ink within said chamber.
Dependencies are inferred from the claim text.