US 12,187,068 B2
Fiber-bundled part for writing instruments, and pen tip and writing instrument using the fiber-bundled part
Toshihiro Takahashi, Fujioka (JP); Toshimi Kamitani, Tokyo (JP); and Hirotake Izawa, Tokyo (JP)
Assigned to MITSUBISHI PENCIL COMPANY, LIMITED, Tokyo (JP)
Appl. No. 18/248,089
Filed by MITSUBISHI PENCIL COMPANY, LIMITED, Tokyo (JP)
PCT Filed Oct. 7, 2021, PCT No. PCT/JP2021/037207
§ 371(c)(1), (2) Date Apr. 6, 2023,
PCT Pub. No. WO2022/075421, PCT Pub. Date Apr. 14, 2022.
Claims priority of application No. 2020-171440 (JP), filed on Oct. 9, 2020.
Prior Publication US 2023/0406029 A1, Dec. 21, 2023
Int. Cl. B43K 8/06 (2006.01); B43K 1/12 (2006.01); B43K 27/02 (2006.01); B43K 27/04 (2006.01); B43K 27/08 (2006.01)
CPC B43K 1/12 (2013.01) [B43K 8/06 (2013.01); B43K 27/02 (2013.01); B43K 27/04 (2013.01); B43K 27/08 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A fiber-bundled part for writing instruments used for an ink feed core leading to a pen tip or a writing pen core, comprising:
a multifilament of long fibers having different melting points, the multifilament at least containing crimped fibers,
wherein a crimp ratio of the crimped fibers that is determined by a following formula (I) falls within a range from 1 to 50%,
the crimp ratio=(a crimp width/a crimp length)×100  (I)
wherein in the formula (I), a distance between a wave crest to a next wave crest in the fiber is defined as a crimp length, and a distance between the wave crest and a trough of a wave in a direction perpendicular to the crimp length is defined as a crimp width.