PRINTED CHARACTER PACKAGE, PACKAGE PRINTING METHOD, AND PRODUCTION HISTORY TRACKING METHOD FOR PRODUCTS

摘要

A printed character, a package, a package printing method, and a method for tracking production history of products are provided to effectively detect a hidden mark by printing a thermal head directly contacting with a printing object in a portion adjacent to a mark. A printed character comprises a mark(10) formed by melting a thermal ribbon by a thermal head on a printing object, and a hidden mark(20) formed by contacting the thermal head directly to the printing object in a portion adjacent to the mark. The mark has a character string including a date of manufacture, and a term of validity. The hidden mark has a character string including a symbol of a manufactured year, a symbol of a manufactured month, and a symbol of a manufactured date. The printing object is a label or a package.