Patent ID: 8857944
Filing Date: 2014-10-14
Classification: B41J

Abstract:
1. A method for transporting a print medium in an inkjet printing apparatus in which the print medium wound in a roll form is fed out, the print medium is transported by roll with two or more drive rollers disposed along a transportation path of the print medium, the print medium is printed with an inkjet print unit disposed above the transportation path, ink adhering to the print medium is dried by a drying section disposed downstream of the print unit, and the print medium is finally wounded and collected in a roll form, the method comprising: a tension-generating step of generating tension on the print medium in accordance with a difference in speed between the two adjacent drive rollers; a tension-detecting step of detecting tension acting on the print medium between the two adjacent drive rollers; a controlling step of controlling rotation speeds of the drive rollers such that the detected value of tension has a target value of tension; and a predictive control step of predicting decrease in tension due to expansion of the print medium during an initial period of starting printing on the print medium until the control step causes the stable detected value of tension, and increasing the rotation speeds of the drive rollers downstream of the print unit to suppress decrease in tension of the print medium.