Printing apparatus and printing method

A printing method, comprising:

• transporting a medium through rotation of a rotating roller of a transport unit;
• imaging the medium with an imaging unit when irradiated with light by a light-emitting unit that intermittently emits light when the medium is transported;
• detecting rotation information of the rotating roller;
• acquiring movement information of the medium based on a plurality of images with different imaging times at which the medium is imaged;
• and
• controlling at least one of a print head that prints on the medium and the transport unit based on the rotation information and the movement information,
• wherein, in the controlling, detection of a timing of the rotation information and a timing of imaging of the medium are synchronized based on the radiation timing at which the medium is intermittently irradiated with light by the light-emitting unit.

A printing apparatus, comprising:

• a transport unit that transports a medium by the rotation of a rotating roller;
• a print head that prints on the medium;
• an imaging unit that images the medium when transported;
• a detecting unit that detects rotation information of the transport unit;
• an acquisition unit that acquires movement information of the medium based on a plurality of images with different imaging times at which the medium is imaged;
• an imaging controller that controls the imaging unit;
• and
• a controller that performs control of at least one of the transport unit and the print head based on the rotation information and the movement information,
• wherein the imaging unit includes a light-emitting unit that irradiates the medium with light, and
• the controller causes the acquisition of the rotation information by the detecting unit and the imaging of the medium by the imaging unit to be synchronized based on the radiation timing at which the medium is intermittently irradiated with light by the light-emitting unit,
• wherein the detecting unit includes an encoder that either directly or indirectly detects the rotation of the rotating roller, a rotation amount detecting unit that detects a rotation amount of the rotating roller based on a detection signal of the encoder, and a latching unit that holds a detection value of the rotation amount detecting unit and acquires the rotation information based on the rotation amount held by the latching unit, and
• the imaging controller controls the imaging unit based on a control signal formed from a pulse signal and provides the control signal to the latching unit, finishes irradiation of the medium with light by the light-emitting unit started during rising of the pulse of the control signal during falling of the pulse, and causes the latching unit to hold a detection value of the rotation amount detecting unit during falling of the pulse of the control signal.