A printing mechanism is provided for a barcode printer and includes a frame, a printing head, a carbon ribbon axle, and a carbon ribbon collection axle. The frame is mounted to an upper end portion of an upper casing member. The printing head is mounted in the frame to effect printing of labels. The carbon ribbon axle is arranged in a lower portion of the frame and is located below the printing head for connecting and retaining a carbon ribbon that supplies a toner required for carrying out the printing of the labels by the printing head. The carbon ribbon collection axle is arranged in an upper portion of the frame and is located above the printing head in an arrangement that is reversed to the carbon ribbon axle to allow the carbon ribbon from the carbon ribbon axle to be rolled up in the carbon ribbon collection axle after the printing operation carried out by the printing head. The carbon ribbon from the carbon ribbon axle can be wound around and collected by the carbon ribbon collection axle in a shortest path. Thus, a printing mechanism featuring a reduced length of carbon ribbon collection path and a reduced size is provided.