Printing device and printing method

A printing method for a printing device, the printing device including a transport section that transports a medium in a transport direction,

• a printing section that performs printing by ejecting liquid onto a print surface of the medium transported by the transport section,
• a drying section that is arranged downstream of the printing section in the transport direction and that dries the medium printed by the printing section, and
• a platen that is arranged at a position facing the printing section with the medium interposed therebetween and that supports the medium, wherein
• the drying section includes a contact heating section that heats the medium by contacting a back surface that is a surface opposite from the print surface,
• the transport section includes a first drive roller that is arranged upstream of the printing section in the transport direction and that applies a transporting force to the medium, a second drive roller that is arranged between the printing section and the drying section in the transport direction and that contacts the back surface to apply a transporting force to the medium, and a third drive roller that is arranged downstream of the drying section in the transport direction and that applies a transporting force to the medium, and
• the printing device includes a first tension measuring section that measures tension applied to the medium at a position upstream of the contact heating section in the transport direction, and a motor that drives the second drive roller,
• the printing method comprising:
• transporting and printing the medium so that output of the motor is (T−X)×r/i+N0+N1, assuming that T is a target value of tension applied to the medium at a position of the platen in the transport direction, X is tension applied to the medium measured by the first tension measuring section, r is a radius of the second drive roller, i is a gear ratio between the second drive roller and the motor, N0 is idling torque measured in advance, and N1 is acceleration torque, which is a product of an inertia moment and an angular velocity of the second drive roller.