| 摘要 |
PROBLEM TO BE SOLVED: To impart an excellent light-resistance to a recording medium by constituting a surface treating agent of a solution containing a water-soluble magnesium salt, or a solution containing a water-soluble magnesium salt and a cationic resin. SOLUTION: This surface treating agent is applied to a recording medium in such a manner that (A) a water-soluble magnesium salt and (B) a cationic resin exist at the same time in the recording medium when being applied to the recording medium. For example, when plain paper is selected as the recording medium, a surface treating agent comprising a solution containing (A) and (B) is used, and also, when an ink jet recording medium already containing (B) in the ink receiving layer is selected, a surface treating agent comprising a solution containing (A), or a solution containing (A) and (B) is used. As the water-soluble magnesium salt, halogenated magnesium, magnesium sulfate or the like is used. As the cationic resin, a polyamine based resin, a quarternary ammonium based resin or the like is used. |
