An object of the present invention is to provide an ink jet print system
in which quality troubles (e.g. banding and ink overflow) caused by an
unsuitable combination of ink and an ink jet recording medium in an ink
jet recording apparatus in the case where the ink jet recording medium is
an imitation, are obviated on the basis of printing control information
obtained from the ink jet recording medium with an information-detecting
sensor, and it is possible to prevent the employment of an ink jet
recording medium which a user cannot judge to be a genuine product or an
imitation. According to the present invention, an ink jet print system
can be obtained in which printing information obtained from an image
processor and the printing control information of the ink jet recording
medium obtained from the information-detecting sensor are processed and
on the basis of information of these kinds, the best image is always
formed with the ink jet recording apparatus by the use of a genuine
product. The printing control information of the ink jet recording medium
is preferably a logo print or a cord image print. The ink jet recording
medium is preferably of a rolled paper type. The system is stopped when
an imitation is used which does not match with the printing control
information.