Invention Grant
- Patent Title: Ballpoint pen tip, ballpoint pen utilizing the ballpoint pen tip and method of manufacturing the ballpoint pen tip
- Patent Title (中): 圆珠笔尖,圆珠笔利用圆珠笔笔尖和圆珠笔笔尖的制造方法
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Application No.: US10687831Application Date: 2003-10-20
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Publication No.: US06887008B2Publication Date: 2005-05-03
- Inventor: Toru Kitao , Hiroyuki Muto
- Applicant: Toru Kitao , Hiroyuki Muto
- Applicant Address: JP Tokyo
- Assignee: Mitsubishi Pencil Kabushikikaisha
- Current Assignee: Mitsubishi Pencil Kabushikikaisha
- Current Assignee Address: JP Tokyo
- Agency: Kubovcik & Kubovcik
- Priority: JP2002-305750 20021021
- Main IPC: B43K1/08
- IPC: B43K1/08 ; B43K7/00 ; B43K7/02 ; B43K7/10 ; B43M11/02

Abstract:
There is provided a ballpoint pen tip that minimizes thin spots such as impact thin spots even if upward writing or an impact causes entry of air, allows rapid return to normal writing, and minimizes manufacturing costs. A writing ball and a check ball included in the ballpoint pen tip are placed close to each other with a slight clearance therebetween to leave an inner space with a slight capacity. Thus, even if air enters from a caulking portion, the volume of the air stored inside is slight, and an air pool can be rapidly eliminated. Further, both the writing ball and the check ball can be provided in a front end of the ballpoint pen tip, and assembly operations can be easily performed without inverting the ballpoint pen tip.
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