Double-sided printing material receiving and discharging structure capable of discharging materials and receiving materials upwards and downwards and printer

The invention discloses a lower-feeding and upper-feeding double-sided printing material receiving and discharging structure and a printer, and belongs to the technical field of printers. The double-sided printing device comprises a case, a double-sided printing assembly is arranged in the case, a discharging assembly and a collecting assembly are arranged in the case and located below and above the double-sided printing assembly respectively, and a drying assembly is arranged at the top of the double-sided printing assembly; the guide rollers are rotationally arranged in the machine box and located at the discharging end of the drying assembly, and the number of the guide rollers is two; the visual camera is adopted to collect the use information of the sponge roller, and the condition that the sponge roller is polluted by ink attachment is judged through machine vision, so that the use condition of the sponge roller is detected and found in time, and the sponge roller is replaced in time, and therefore, the