US 12,325,255 B2
Writing instrument
Toshimi Kamitani, Tokyo (JP); Chihiro Mochizuki, Tokyo (JP); and Wataru Sagawa, Tokyo (JP)
Assigned to MITSUBISHI PENCIL COMPANY, LIMITED, Tokyo (JP)
Appl. No. 18/718,309
Filed by MITSUBISHI PENCIL COMPANY, LIMITED, Tokyo (JP)
PCT Filed Dec. 14, 2022, PCT No. PCT/JP2022/046006
§ 371(c)(1), (2) Date Jun. 10, 2024,
PCT Pub. No. WO2023/112955, PCT Pub. Date Jun. 22, 2023.
Claims priority of application No. 2021-205416 (JP), filed on Dec. 17, 2021; and application No. 2022-172667 (JP), filed on Oct. 27, 2022.
Prior Publication US 2025/0042194 A1, Feb. 6, 2025
Int. Cl. B43K 1/12 (2006.01); B43K 23/08 (2006.01); B43K 23/12 (2006.01); C09D 11/16 (2014.01)
CPC B43K 1/12 (2013.01) [B43K 23/08 (2013.01); B43K 23/12 (2013.01); C09D 11/16 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A writing instrument comprising at least:
a barrel in which an aqueous ink is contained;
a pen tip provided on a tip side of the barrel and capable of discharging the aqueous ink; and
a cap that is removably attached on a pen tip side of the barrel, wherein
the aqueous ink has a vapor pressure of 10.3 to 12.3 kPa at 50° C.