Reusable hidden indicia printed sheet
OwnerKiyoharu Kawashimainventor
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Abstract
A print of this invention has a color-forming area and a discoloring area. The color-forming area is printed by an ink containing a first color-changing agent which changes from substantially invisible colorlessness to visibleness by applying a color former. The discoloring area is printed by an ink containing a second color-changing agent which changes a from substantially invisible colorlessness to visibleness by applying the color former and returns to invisible colorlessness state as the time passes naturally after changing its color.
Claims6
A reusable hidden indicia printed sheet comprising a paper containing a first color-forming area printed thereon by using an ink containing a first color-changing agent which changes from substantially invisible colorlessness to visibleness by applying a color former, wherein said color former comprises a solution pH indicator and a second color-forming area printed upon the paper separate from said first color-forming area by using an ink containing a second color-changing agent which changes from substantially invisible colorlessness to visibleness by applying said color former and fades to a colorless state quickly whereas said first color-forming area fades to a colorless state slowly.
Dependencies are inferred from the claim text.