1. An inkjet printing apparatus comprising: an inkjet head having nozzles which eject ink; a first conveyance device which moves at least one of an image formation medium and the inkjet head during image formation by the inkjet head so as to causes relative movement of the image formation medium and the inkjet head; a second conveyance device which conveys the image formation medium along a conveyance path after the image formation by the inkjet head; an imaging device which is disposed in the conveyance path and captures an image of a print result recorded on the image formation medium; a test pattern printing control device which controls ejection of the inkjet head in such a manner that an inspection test pattern for inspecting ejection quality of the inkjet head is recorded on the image formation medium; an ejection failure nozzle detection processing device which identifies a position of an ejection failure nozzle of the inkjet head on a basis of information obtained by capturing an image of a print result of the inspection test pattern by the imaging device; an expansion-contraction reference mark printing control device which controls ejection of the inkjet head so as to record expansion-contraction reference marks that form reference points for measuring a distance between at least two points, in a periphery outside an image forming region of a first surface of the image formation medium, when printing is performed on the first surface; an expansion-contraction deformation amount measurement device which obtains information indicating an amount of deformation due to expansion and contraction of the image formation medium, from information obtained by conveying, by the second conveyance device, at least one sheet of a first surface-printed image formation medium whose first surface has already been printed, prior to printing on a second surface which is a rear surface of a print object obtained by the printing on the first surface, and capturing, by the imaging device, an image of the expansion-contraction reference marks recorded on the first surface of the at least one sheet of the first surface-printed image formation medium, when the printing is performed on an image forming region of the second surface after the printing on the first surface; an image deformation processing device which applies image deformation processing corresponding to the amount of deformation due to expansion and contraction, to image data to be printed on the second surface, on a basis of the information indicating the amount of deformation due to expansion and contraction; and a print control device which carries out the printing on the second surface on a basis of the image data which has been corrected through the image deformation processing.