| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for measuring the thickness of a liquid layer on a metering roll. SOLUTION: A nip is formed by forming a pair of a backup roll 83 and a transfer roll 81, a sheet passes through the nip and them, one side of the sheet is humidified. An adjustable metering roll 84 is engaged with the transfer roll. A portion of the metering roll 84 is arranged in a liquid storage tank 85 containing a liquid and, there by, the liquid is added on the outer surface of the metering roll 84. An optical sensor 7 is arranged to detect light reflected from the liquid on the outer surface of the metering roll 84. A 'go-on' signal or a 'not go-on' signal showing whether or not the metering roll 84 comes into contact with the transfer roll 81 is emitted by the optical sensor 87. The appropriate thickness of the liquid layer on the surface of the metering roll 84 is obtained by adjusting the metering roll 84. |
