Ink drying device of letterpress printing machine

According to the ink drying device of the letterpress printing machine, a sealed preheating channel is arranged at the bottom of an ink storage cylinder, and an air inlet pipe and an air outlet pipe which communicate with the preheating channel are arranged on the ink storage cylinder; a microwave generating device is arranged in a hard plastic bin of the drying assembly; the hard plastic bin is a sealed part and is provided with a passing groove for a workpiece to be printed to pass through; the microwave generating device is arranged in the hard plastic bin, microwaves generated by the microwave generating device can quickly and comprehensively dry the water-based ink from inside to outside, the phenomenon of false drying and after-tack is avoided, and additionally generated excessive heat is conveyed into the preheating channel of the ink storage cylinder through the air collecting cylinder and the exhaust fan to preheat the water-based ink. Energy recycling is achieved, and the utilization rate is increas