Ink and ink set

#The present invention relates to an ink that can be used for producing prints.

#In the industry, a method of performing printing on packaging materials and advertising media using an ink jet printer has been considered. Examples of the packaging material include a cardboard sheet and a cardboard box adhered in a state where a paperboard processed into a wave shape is sandwiched between two paperboards.

#Examples of the cardboard include a cardboard made of a paperboard that easily absorbs a solvent contained in the ink, and a cardboard provided with a colored layer that hardly absorbs the solvent in the ink on the surface of the paperboard.

#FIG. 1 is a schematic view of a microreactor used in the present invention.

#The ink of the present invention is an ink for use in an ink jet recording method in which the distance from a surface (x) having an ink discharge port of an ink jet head to a position (y) where a line perpendicular to the surface (x) intersects with a recording medium is 2 mm or more. The ink has a viscosity in the range of 2 mPa·s or more and less than 9 mPa·s and a surface tension in the range of 20 mN/m to 40 mN/m.

#In the ink jet recording method that can use the ink of the present invention, it is possible to use an ink jet recording apparatus having a configuration in which the distance (gap) from the surface (x) having the ink discharge port of the ink jet head to the position (y) where the line perpendicular to the surface (x) intersects with the recording medium is 2 mm or more, and is preferably 3 mm or more.

#Regarding the distance from the surface (x) to the position (y) where the line perpendicular to the surface (x) intersects the recording medium, a lower limit of the distance is preferably 3 mm or more, and an upper limit of the distance is preferably 10 mm or less and is particularly preferably 5 mm or less in order to produce a print in which even if the recording medium is large and easily warped, contact between the surface of the recording medium and the ink discharge port is prevented to effectively prevent ink discharge defects due to damage to the ink discharge port and deterioration of a water repellent function often provided in the ink discharge port, and even in a case where the distance between the surface of the recording medium and the ink jet head is long, the occurrence of the streaks is not observed.