To provide a drying unit capable of efficiently drying a sheet medium including an oil-based ink layer and a water-based varnish layer in a short time.
The drying unit 20 includes a first light source unit 30 irradiating a sheet P with light in a far-infrared region and a second light source unit 40 irradiating the sheet P with light in a near-infrared region, in order from an upstream side of a conveyance route of the sheet P. The sheet P is entirely internally heated by far-infrared rays emitted by the first light source unit 30, and the water-based varnish layer located on a surface layer of the sheet P is dried by near-infrared rays emitted by the second light source unit 40. If the water-based varnish layer is dried first and cured, it is difficult to dry the oil-based ink layer of the inner layer. In accordance with the drying unit 20, because the oil-based ink layer is dried first, both oil-based ink layer and water-based varnish layer are satisfactorily dried.
OKA TERUTO
AOKI YOSHITOMO
MINAMIYAMA SEIJI
WANAKA HIROSHI
Masataka Otani
Haruhiro Hirata