Printing machine

The utility model provides a printing machine, which comprises a printing plate wheel, a printing ink feeding portion and a printing plate wheel adjusting mechanism. A fixed rod penetrates through the center of the printing plate wheel, two ends of the fixed rod are arranged in a pair of grooves on lateral plates of the printing machine, the printing plate wheel adjusting mechanism is used for clamping the fixed rod to operate the fixed rod to move up and down in the grooves, the printing plate wheel can be tightly attached to the printing ink feeding portion to receive printing ink supplied from the printing ink feeding portion, and a printing procedure can be conducted smoothly. The printing plate wheel adjusting mechanism is used for adjusting upper and lower positions of the printing plate wheel to enable printing plate wheel of different diameters to be all arranged in the printing machine, and printing procedures can be conducted on printing products of different unit size length.