A two color printing ribbon mechanism for adding, calculating or the like machines in which the ribbon has two differently colored sections arranged end-to-end. Normally, a first and most frequently used ribbon section is held in contact with an inking device and the second less frequently used ribbon section is located at the printing line. During a cycle of the machine in which the first section is to be used for imprinting, and prior to the printing operation, the ribbon is moved endwise to locate the first section at the printing line and to move the second section into contact with a second and appropriately colored inking device. During a cycle in which the second section is to be used for imprinting, the ribbon moving mechanism is merely disabled, leaving the second ribbon section at the printing line during the printing operation.