The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 23, 2021
Filed:
Jun. 12, 2017
Mitsubishi Pencil Company, Limited, Tokyo, JP;
Hiroyuki Arai, Fujioka, JP;
Satoru Banzai, Fujioka, JP;
MITSUBISHI PENCIL COMPANY, LIMITED, Tokyo, JP;
Abstract
In a pencil lead manufactured through a baking step regardless of being a black lead or a colored lead, the mechanical strength of the pencil lead is further increased by coating a surface thereof with a resin. A pencil lead includes a baked lead body whose surface is covered by a covering layer made of resin that has a scratch hardness of HB or greater. The scratch hardness of the resin as a subject resin is defined as a lowest hardness index of a tester pencil that is able to form an indentation on a surface of a horizontal flat plate coated with a 5-μm thick film of the subject resin, when the surface is scratched by the tester pencil being pressed onto the surface at an angle of 45° with a load of 7.355 N.