Abstract: In an ink composition comprising a water-soluble dye or a pigment, dissolved or dispersed in an aqueous medium, the ink composition fulfills at least one of the following conditions 1 to 6 in respect of the concentration of metals contained therein:Condition 1; Barium concentration, not more than 4 ppmCondition 2; Zinc concentration, less than 1 ppmCondition 3; Nickel concentration, less than 0.05 ppmCondition 4; Strontium concentration, less than 0.01 ppmCondition 5; Iron concentration, not more than 0.3 ppmCondition 6; Silicon concentration, less than 1.5 ppm.

Abstract: A hot melt ink includes at least one wax substance having a melting point at a temperature ranging from 50.degree. C. to 150.degree. C. and a coloring agent substantially free of insoluble ingredients not soluble in the at least one wax substance. By removing insoluble ingredients from the coloring agent, for example by filtration, a hot melt ink is obtained that does not clog the printing head.

Abstract: A hot-melt type ink composition for use in an ink jetting printing apparatus, which is in a solid phase at room temperature, and is to be liquefied by heating at an elevated temperature above the room temperature so as to effect printing. The ink composition of the invention contains a wax having a melting point in a range of 50.degree. C. to 150.degree. C., a resin, a dye and at least one amide.

Abstract: A hot melt ink of high performance and clear appearance as ink used for hot melt type ink jet recording comprising a paraffin wax as a normal temperature solid wax, ethylene-vinyl acetate copolymer as a resin and an oil-soluble dye (C.I. SOLVENT BLACK 3) as a colorant and a plasticizer having a molecular weight from 100 to 10,000 comprising at least one of materials selected from the group consisting of aliphatic ester, aromatic ester, phosphoric acid ester and oxyacid ester, more preferably, at least one of materials selected from the group consisting of phthalic acid ester, fatty acid ester, polyester type plasticizer, epoxy type plasticizer and trimellitic acid type plasticizer and, most preferably, dioctyl phthalate which is liquid at normal temperature.