Abstract: In an inking apparatus for use in a printing machine having an ink pot and a plurality of juxtaposed ink metering keys and adjusting means for moving the ink metering keys toward and away from the peripheral surface of an inking roller in contact with the ink contained in the ink pot, there are provided center supporting keys on both sides of the ink metering key located at the axial center of the inking roller, and adjusting means for reciprocating the center supporting keys toward and away from the periphery of the inking roller independently of the ink metering keys.

Abstract: A water film surface is irradiated with light from a detecting unit's light source. Light reflected from the water film surface is converted into an electrical signal by a sensor (photoelectric converting means) in the unit. The converted electrical signal is supplied to a processing unit through a cable. The processing unit calculates the water film thickness based on the electrical signal. The calculated thickness is displayed on a display in the detecting unit.