Patent ID: 7806972

Claim:
An oil ink set in which at least a first oil ink, a second oil ink and a third oil ink each contain a coloring material and are combined together, characterized in that said first, said second, and said third oil ink has a wavelength region in which its reflectivity on a recording medium changes from 80% to 5% in a wavelength range of 400 nm to 700 nm; in the wavelength region where the reflectivity of said first oil ink changes from 80% to 5%, the reflectivity of said second oil ink is continuously higher than that of said first oil ink, and in the wavelength region where the reflectivity of said second oil ink changes from 80% to 5%, the reflectivity of said third oil ink is continuously higher than that of said second oil ink; wherein said first oil ink is pigment red 122, said second oil ink is an orange ink or red ink selected from the group consisting of pigment orange 64, pigment orange 71 and pigment red 254, said third oil ink is a yellow ink selected from the group consisting of pigment yellow 150 and pigment yellow 180; the coloring materials in said first, said second and said third oil ink are all different; and each of said oil inks contains at least 30% by mass of a polyoxyethylene glycol dialkyl ether represented by the following general formula (1) and/or a polyoxyethylene (alkylene) glycol alkyl ether acetate represented by the following general formula (2), and a (meth) acrylic resin as a fixing resin X 1 —(OC 2 H 4 ) n —OX 2 General Formula (1) wherein X 1 and X 2 are each an alkyl group having 1 to 3 carbon atoms and may be identical or different, and n stands for an integer of 2, 3, and 4 wherein X 5 is an alkyl group, X 6 is a hydrogen atom or an alkyl group, and n stands for an integer of 1, 2, 3, and 4.