Other

Hiroyuki Nagakura

Yutaka Ishiyama

Kimiya Yamada

Eisuke Tsuda

A wet-type plate-making machine is disclosed in which the amount of a developer in a developing tank and the toner concentration of the developer are maintained constant. In accordance with the detection values of two liquid level detection switches mounted in the developing tank, the developer is supplied from a developer refill pump thereby to maintain a constant amount of developer. The toner concentration of the developer is maintained constant by supplying the toner from a toner refill pump when the detection value of a concentration detection unit of light-transmission type is low, and by supplying the developer from a developer refill pump when the detection value of the concentration detection unit is high. In the case where the developer concentration or the toner concentration fails to change in this control operation, an alarm signal is outputted indicating that the developer bottle or the toner bottle, as the case may be, is empty. Also, in order to eliminate the effect of contamination due to secular variations, the concentration detection unit is recalibrated by changing the luminous intensity of a light-emitting device continuously. Further, a fixing unit is configured to improve the heating efficiency by fully utilizing the heat of the heated internal air of the plate-making machine.

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Tokyo, Japan

Hiroyuki Nagakura