PURPOSE: To make it possible to strap an article to be strapped without buckling and perform a strapping of a high grade by performing a binding control by detecting a quantity of deformation of recording papers at the time of strapping, for a recording device which is equipped with a strapping machine to strap recording papers by a tape, etc., as a recording paper process after the completion of recording.

CONSTITUTION: A strapping machine at a recording paper strapping process section which is provided on a copier, etc., lets out a tape 15 which is unwound from a tape roll 15a by the rotation of a driving roller 19 into a loop form by cooperating with a tape guide 16. Then, recording papers P of which the recording is completed are stacked on a tray in the loop of the tape 15, and when the recording of a specified number of recording papers is completed, the stack of recording papers is strapped by the retraction of the tape 15 by the reversal rotation of the driving roller 19. Then, the tape is joined by a tape joining member 21 and is cut. In this case, a quantity of deformation (buckling height) of the article to be strapped accompanied with the tightening of the tape 15 is detected by a reflection type light sensor array 90, etc., and when the measured value reaches a specified value, it is controlled to complete the retraction.