153
m Drum Section
chap.2
Description
At times other than printing, the ink roller is separated from the inner surface of the drum by a fixed
clearance. During printing, however, the press roller rises and presses the ink roller into contact with the
drum inner surface, so that ink is supplied via the drum inner surface to the printing paper. This mechanism
prevents ink from being supplied to the drum inner surface if the printer is run without any paper.
When the master is detached in the platemaking process, ink on the drum surface is removed along with the
document, which means that in the first printing after the master is attached, there is a possibility of
insufficient ink on the drum surface, resulting in faint images.
To prevent such ink insufficiency when in the first printing, the machine is equipped with a mechanism for
raising and lowering the ink roller. Before paper is fed in, this mechanism pushes the ink roller against the
drum inner surface, so that ink is forcibly supplied immediately prior to the start of printing. As a result, the
images on the first sheet printed after platemaking are sufficiently bold.
Ink roller rise and descent operations are included as elements in the Fine Start mode, together with contact
pressure adjustment, and therefore are optimally controlled in accordance with room temperature, length of
time out of use, number of sheets in last run, etc.
Ink roller
rise/descent motor
Ink roller
rise/descent switch
Drive PCB unit
Main PCB
Circuit
(2) Ink Roller Rise/Descent Mechanism
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