Adjustment of the wetting device
The adjustment of the wetting device is the "flat water roller" in the printing process. The basic principles of the "flat water roller" and the "flat ink roller" are the same. The adjustment of the two water delivery devices is introduced below.
1 Adjusting method of oscillating water transfer roller wetting device
Most domestic offset presses use a oscillating water transfer roller wetting device (see Figure 5-2). The water roller of this device is relatively easy to disassemble. The adjustment method is to let the water roller contact the printing plate or the water roller, using a width of about 35 -40mm, thickness 0.15-0.25mm steel sheet, inserted on the water roller / plate or water roller / string water roller, the contact pressure is judged according to the feel and experience, and the pressure is based on the slope principle Make the adjustment of the cone head. The contact pressure of the water transfer roller / string water roller is controlled according to the spring force, while the swing water bucket roller is controlled by a cam, and its adjustment is relatively easy.
[Expert Tips]
The feel and experience of the operator of the offset press is very important, for example, the weight of the paper, the thickness of the blanket, the thickness of the ink layer of the printed matter, and the contact pressure of the water and the ink roller are judged by the feel, so the operator It is necessary to exercise its feel regularly, and constantly sum up experience to keep different "feels" in the brain. Form a deep memory.
2 CD102 machine wetting device adjustment method
Dagren wetting devices generally have 5-6 water rollers. The adjustment method of Dagren-type wetting device is explained below with CD102 machine wetting device as an example:
· Water roller R (unmovable): roller surface chrome plating · Water bucket roller T (Figure 5-3 / ①): surface is rubber, the roller surface is ground · Metering roller D (Figure 5-3 / ②): surface Chrome plating · Intermediate roller Z (Fig. 5-3 / ③): Nylon roll surface · Water roll A (Fig. 5-3 / ④): Roll surface is rubber
(1) Remove the water roller
a. Loosen the screw (Fig. 5-4 / â‘ ) on the roller neck of the operation surface, and take it out.
b In order to separate the roller A from the R, on each side of the transmission surface and the operation surface, turn the adjustment screw (Figure 5-4 / â‘¡) of the water string roller R counterclockwise for two weeks.
c Push the roller towards the operation surface, lift the roller from the transmission side and remove it.
Figure 5-4 Remove the water roller [next]
(2). Install and adjust the water roller A
a. Insert A (Figure 5-5 / â‘ ) (the plane of the roll neck points upward) into the bearing of the operation surface (Figure 5-5 / â‘¡).
b Insert the water roller into the bearing of the transmission surface until it contacts the stop plate, and then push it toward the operation surface.
c. Tighten the hexagonal screws on the operation surface (Figure 5-5 / â‘¢) to fix the roller neck in the bearing sleeve.
Figure 5-5 Installing and adjusting the water roller
Preparation before adjustment:
· Install the printing plate on the plate cylinder.
· Adjust the ink roller F.
· Install the middle roller Z, connect the inking system and dampening system.
· Lubricate all bearing points · The machine jogs forward at a slow speed, so that the plate cylinder is geared toward the paper collecting device.
d Adjust with a piece of paper.
e. Insert two paper strips between the rollers to be adjusted on the transmission surface and the operation surface. Place a strip of paper with a width of approximately 5 cm against the rubber roller and a strip of narrower paper (approximately 2 cm) against a smooth roller / plate. The total thickness of the two paper strips is about 0.10mm.
f. Determine the adjustment amount by pulling the paper.
? Tip: All adjustment screws (except the support spring of the middle roller) have their specific adjustment directions. Turn the screw clockwise to increase the contact pressure, and turn counterclockwise to decrease the contact pressure.
The first adjustment should use the note method. After adjustment, light ink should be used to verify the results.
[Expert Tips]
The adjustment of the water roll A is very important in the wetting device. Both the metering roll D and the intermediate roll Z are based on it, and the adjustment method is the same. The indentation width can be checked according to the numerical values ​​in Figures 5-6.
[Related Links]
The arrangement of the water rollers in the wetting device of the web offset press is basically the same, and it is generally transmitted by a short water path, which is conducive to the rapid transmission of the wetting liquid.
Figure 5-6 Check the contact pressure of the water roller
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