| 摘要 |
PURPOSE:To make an image on a printing plate parallel to the printing cylinder of an offset printing machine when the plate is automatically fed thereto. CONSTITUTION:An offset printing machine comprises a sleeve having a tapered side face mounted to a gripper shaft 5 provided on the shaft 2 of a printing cylinder in parallel relation in a manner to permit the movement of the sleeve in the shaft direction; a cylindrical member 25 provided on the shaft 2 of the printing cylinder in a manner to permit its movement in the shaft direction, the cylindrical member 25 and the sleeve being coupled together by a rocking arm; a screw 18 provided in contact with the tapered side face of the sleeve, the screw 18 being fixed to a bracket 16 mounted to the gripper shaft 5; and a plate 13, a gripper 10 and a front plate provided on the gripper shaft 5, the front plate being movable. The amount of a shift from the regular position of an image on the printing plate is obtained from the two perpendicularly intersecting lines 47b and 47c formed on the grip end. Since this method has the feature of being able to read the image position by drawing the two lines 47b and 47c in an arbitrary thickness, the possibility of an error occurring due to the mismatching in shape of register marks can be eliminated, whereby the image position can be detected accurately. |
