Abstract: A pair of parallel lead screws are meshed with a pair of helical racks provided on opposite faces of a movable stage slidable on a flat or cylindrical base plate. The pair of parallel lead screws are driven by a pair of electric motors independently of each other. One of the helical racks has teeth extending in a direction to intersect with the teeth of the other helical rack. By selecting the direction of rotation of the pair of lead screws independently, the direction of movement of the stage can be selected. The stage may be made of a pair of plates having the helical racks on the inner or outer faces of the plates.

Abstract: A cathode-ray tube image recording device for recording images on a photosensitive thermal development recording medium which may have a reduced sensitivity due to time deterioration. An image of a density wedge is exposed and developed then sensed to determine the sensitivity of the recording medium. The sensing operation produces a density identification step number which is used to set one or both of the brightness and light emission time of the cathode-ray tube in accordance with a predetermined characteristic curve or function. A switchable resistor circuit or read-only memory may be used for applying the characteristic function.

Abstract: An X-Y movement mechanism, having right-handed and left-handed lead screws arranged in parallel with each other and drive sources for individually rotating the lead screws. Gears placed over nuts engage the lead screws, the gears having teeth coaxially with said nuts. A base plate, either flat or cylindrical has a stage slidable thereon. A rack is fixedly provided on the stage to engage the gears. The gears operate as a gear transmission mechanism permitting the rack to move in a direction perpendicular to the direction of the axes of the lead screws and in the direction of the axes of the lead screws.