Title:
BALL-POINT PEN TIP
Document Type and Number:
Japanese Patent JP2017213765
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To prevent a line-drawing part from being shadowed by a ball-point pen tip by forming the leading edge of the ball-point pen tip as thin as possible, and to prevent bending or buckling before refill ink is consumed.SOLUTION: A ball-point pen tip 10 is provided with: a cylindrical holder 11 in which a back hole 12 is formed; a writing ball 16 that is rotatably gripped in the tip of the holder 11; and a caulking part 11E that holds the writing ball 16 in the tip of the holder 11. A tip curved surface 11C formed by an inward-projected multi-degree curved surface and gradually increased in outer diameter from near the caulking part 11E toward a rear side is provided at the tip part of the holder 11, and a value defined by P=π(a-b)/(32a) exceeds 0.03 (mm), in which a (mm) represents an outer diameter at an arbitrary point of the tip curved surface 11C, and b (mm) represents an inner diameter of the back hole 12 at the arbitrary point.SELECTED DRAWING: Figure 4
Inventors:
IGAI ATSUYUKI
YANAGI HISANORI
YANAGI HISANORI
Application Number:
JP2016108829A
Publication Date:
December 07, 2017
Filing Date:
May 31, 2016
Export Citation:
Assignee:
MITSUBISHI PENCIL CO
International Classes:
B43K1/08
Domestic Patent References:
| JP2015013426A | 2015-01-22 | |||
| JP2003039870A | 2003-02-13 | |||
| JP2007518838A | 2007-07-12 | |||
| JP2004107598A | 2004-04-08 | |||
| JP2005297551A | 2005-10-27 |
Foreign References:
| US5520473A | 1996-05-28 |
Attorney, Agent or Firm:
Patent Service Corporation Taiyo International Patent Office
Hiromichi Kuroda
Tomohide Kitaguchi
Hiromichi Kuroda
Tomohide Kitaguchi