To uniformize heating conditions on both surfaces of a recording sheet upon heat development of the sheet having image forming layers formed on both surfaces.
The heat developing device functions to heat a heat developing recording sheet having image forming layers made of a photosensitive material formed on both of the top and back surfaces of a sheet type support and to heat develop latent images recorded in the respective image forming layers on both surfaces to visualize; and the device is equipped with first heating plates 21, 23 touching the top surface from an upper side in a gravity direction, with second heating plates 22, 24 alternately disposed with the first heating plates 21, 23 in a staggered state and touching the back surface from a lower side in a gravity direction, and with a controlling means 19 to control the heating temperature of the second heating plates 22, 24 higher than that of the first heating plates 21, 23. Thus, the temperature on the heating surface in the lower side of the heating plates 21, 23 is controlled to be the same as the temperature on the heating surface in the upper side of the heating plates 22, 24, which results in uniform heating conditions on both surfaces.
TORISAWA NOBUYUKI
Hironori Honda
Toshimitsu Ichikawa
Takeshi Takamatsu