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:
Oct. 23, 2001
Filed:
Sep. 20, 1999
Shinji Tsujio, Sakai, JP;
Sakura Color Products Corporation, Osaka, JP;
Abstract
The invention provides an aqueous ink composition which can be erased relatively easily even after writing with a great tool force. The invention relates to (1) an erasable aqueous ink composition containing at least one colorant, characterized in that the colorant has a mean particle size of not less than 2 &mgr;m and that particles having a size of not more than 1.8 &mgr;m account for not more than 1.6% by weight of said colorant; (2) an erasable aqueous ink composition containing at least one colorant, characterized in that the colorant has a mean particle size of not more than 7 &mgr;m and that particles having a size of not less than 7 &mgr;m account for not more than 0.5% by weight of said colorant and (3) an erasable aqueous ink composition containing at least one colorant, characterized in that the colorant has a mean particle size of 2 to 7 &mgr;m, that particles having a size of not more than 1.8 &mgr;m account for not more than 1.6% by weight of said colorant and that particles having a size of not less than 7 &mgr;m account for not more than 0.5% by weight of said colorant.