the cover 12 from rotating while it is positioned on the supporting rod 38 in order to facilitate the insertion of the ink roll means 30 with its cover 12 on the supporting rod 38 the lever 78 which is pivotally mounted on the pin 80 which is secured to the side frame 70 may be rotated in a counterclockwise direction so as to pivot the lever 68 on its pin 72 in a counterclockwise direction as viewed in fig4 so as to move the lever 68 to the dashed position shown at 68 1 when the lever 68 is in this position the ink roll means 30 is separated from the inking roller 82 which is part of the printer this enables an old ink roller means 30 with supporting cover 12 to be removed from the supporting rod 38 and facilitates the mounting of a new unit thereon the diameter of the ink roll means 30 is slightly smaller than the internal diameter of the cover 12 when viewed from the assembled relationship shown in fig4 so as to facilitate the mounting of the ink roll means 30 and cover 12 on the supporting rod 38 when the ink roll means 30 is to be brought into cooperative relationship with the ink roller 82 the lever 78 is simply rotated in a clockwise direction as viewed in fig4 and the tension spring 84 resiliently biases the ink roll means 30 into engagement with the inking roller 82 this inking roller 82 is fixed to a shaft 85 which is rotatably mounted in the supporting frame 70 and which is also.