Patent ID: 6811251
Filing Date: 2004-11-02
Classification: C09D

Abstract:
An image recording apparatus based on a color ink-jet scheme provided with an ink set consisting of one or more than one colors of inks containing a color dye and water as the indispensable components and a black ink containing a black pigment and water as the indispensable components, and an ink-jet printing unit which performs printing with these inks on a plain paper having a degree of flatness and smoothness of 100 seconds or less, wherein:the initial contact angles &thgr;0 of the two colors of inks, namely, at least one color ink and the black ink of said ink set, fall within the range from 30 to 80Â° on the plain paper having a degree of flatness and smoothness of 100 seconds or less; as for one of said two colors of inks, the ink A, and the other ink, the ink B, the contact angle variation Xa of the ink A as obtained by the dynamic liquid absorption measurement after the elapsed time of 1 second falls within the range âˆ’70wherein the contact angle variation X=&thgr;âˆ’&thgr;0, the dot area ratio Y=rt2/r02, 0.10 and rt denote respectively the radii of the dots at the time of printing with the ink A or the ink B and after the elapsed time of ta or tb seconds therefrom; incidentally, the liquid droplet volume in the dynamic liquid absorption measurement is 2 &mgr;L.