To provide an offset press enabling quick and precise adjustment of tone and density as to a printing plate cylinder having different pattern area ratios.
The offset press 10 is equipped with an ink arrangement 24 comprising an ink roller 25 and many ink supply blades 16, the printing plate cylinder 30 connected to the ink arrangement 24 through the intermediary of an ink transfer roller group 27, and a blanket cylinder 31. The printing plate cylinder 30 has different pattern area ratios along the width direction, while a key opening degree of each ink supply blade 16 is adjusted by a control part 20 through the intermediary of a driving mechanism 16a. The control part 20 has an ink supply control amount per a unit tone adjustment instructive amount built in for each ink supply blade 16. This ink supply control amount per the unit tone adjustment instructive amount is determined beforehand by using the pattern area ratios of the printing plate cylinder 30.
Hiroyuki Nagai
Junpei Okada
Hirohito Katsunuma
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