Patent ID: 7465112

Claim:
An airtight retractable writing device, comprising: a shaft; an ink-box inside the shaft; a nib connected with the ink-box; a retractable unit controlling movement of the nib within the shaft; and a nib airtight unit with a lid that prevents the nib from drying when the nib is retracted inside the shaft, wherein the nib airtight unit includes an airtight body having: an upper body; a lower body separate from the upper body, wherein the lower body has an outside diameter that is less than an inside diameter of the upper body such that the lower body is inserted telescopically into the upper body and is tightly fitted to the upper body; and an airtight seal pressed between the upper body and the lower body, wherein the center of the airtight seal has a hole whose diameter is smaller than the diameter of the nib or a structure holding the nib while permitting the nib or its holding structure to pass through the hole, and wherein the outside of the airtight body includes two or more flanges that engage two or more grooves inside the lower portion of the shaft.