JPS5892564A - Wetting apparatus - Google Patents

Abstract

PURPOSE:To provide a wetting apparatus for an offset printing press which facilitates the regulation of the quantity of width-wise water by arranging a doctor adjacent to a water roller to be divided into several sections in the axial direction of the water roller so that the setting of the interval can be performed between the surface of the wall roller and the tips of the doctor sections as desired. CONSTITUTION:A doctor 5 is so arranged adjacent to a water roller 3a hydrouphilic and hard in the surface by chrome plating or the like that the clearance can be divided into several sections in the axial direction of the roller between the doctor and the surface of the roller 3a. Then, the interval is enabled to be set between the tips of doctor sections 5 and the surface of the water roller 3a as desired.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dampening device that can be applied to offset printing machines (sheet-fed presses, rotary presses).

FIG. 1 shows a plate cylinder of a conventional offset printing press, A (2) shows an ink section, and an example of its roller group. ■ is a plate cylinder to which an offset printing plate is attached.

There are also other blanket cylinders and impression cylinders that make up the printing unit, but they are not shown here.

In the dampening device (1), the swimsuit is wrapped in rubber on a roller. (2) is a chrome plated roller, which is plated with hard chrome or porous chrome.

(3) is the water roller, which is wrapped with rubber. (4) is a water tank.

2 and 8 show other conventional dampening devices different from the dampening device shown in FIG. 1, respectively. First, in Fig. 2, (1) is the swimsuit roller (rubber wrapped), (8→ is the water head roller (chrome plated), and (2α) is the draining roller (rubber wrapped).Next, in Fig. 8, (1) ) is a swimsuit roller, (2) is a chrome-plated roller, (2α) is a passing roller (rubber IT), c
aa) is a water roller (chrome plated).

Now, in all of FIGS. 1, 2, and 8, the vehicle is allowed to slip in the operating state at the X-marked portion. Now, referring to the case in Figure 1, roller (1) is rotating at the same peripheral speed as plate cylinder ■, but roller (2) and roller (3) are meshed with gears (not shown), and this - The set is driven by a separate power source (motor, etc.) whose rotation speed can be controlled. The same applies to FIGS. 2 and 8.

By the way, the water supply amount in such a structure is controlled as follows. Figure 4- and Figure 1 h-ra (2) (
Extract the part 3), show it, and explain it in detail. In FIG. 4, roller (2) performs metering, and (3) is the water source roller. In Figure 4, the metering roller (
2) Although the rough flow roller is shown and the water head roller (3) is shown as a rubber roller, the same applies even if this combination is reversed depending on the configuration. Further, the amount of water (A+B in FIG. 6) during roller feeding is increased or decreased by increasing or decreasing the nip pressure between the metering roller (2) and the water base roller (3), or by increasing or decreasing the rotational speed of this pair of rollers.

Next, increase or decrease the amount of water on one side of the roller width (C and D in Figure 6).
(state)), the distance between the bearings of one of the roller shafts of rollers (2) and (3) is increased or decreased. Further, in order to reduce the amount of water in the intermediate portion, one roller bearing of the roller (3) is twisted (provided with a gap) as shown in (3) (state E). That is, these basic adjustments A to E (FIG. 6) are performed in combination.

However, in printing work, the patterns to be printed are diverse,
The pattern ratio in the roller width direction (that is, the M/c width direction) is diverse (as schematically shown in FIG. 5). If it is desired to increase or decrease the amount of dampening water in accordance with the pattern ratio due to ghosting, ink gloss on the pattern surface, or other print quality, the above-mentioned adjustment items A to E are not sufficient. An ideal water system would need to supply water in proportion to the amount of ink as shown in Figure 11, but this was not possible with conventional roller-to-roller dampening systems.

The present invention has been proposed in order to solve the above-mentioned conventional drawbacks, and includes a doctor that is divided into a plurality of parts in the axial direction of the roller adjacent to the roller with a solid surface among the rollers that constitute the dampening device. However, it is an object of the present invention to provide a dampening device in which the amount of water in the width direction can be easily adjusted by making it possible to arbitrarily set the distance between each doctor tip and the roller surface.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 shows an embodiment of the present invention, where ■ is a dampening device, ■ is an inking device (rollers are not shown), ]l[ is a plate cylinder. . Also(
1) is the swimsuit roller (rubber wrapped), (2α) is the draining roller (rubber wrapped), (344;! Mizumoto roller, (4) is the water tank. (5) is the doctor and 11 Mizumoto roller (8α
) is divided into multiple parts in the axial direction of the roller. FIG. 7 shows an example of the overall structure, and FIGS. 8(a) and 8(b) show detailed views of a portion of the doctor in FIG. 7.

The water roller (8α) is a hydrophilic solid roller such as chrome plated. In addition, as shown in Fig. 8, the amount of water supplied in the width direction is arbitrarily controlled by adjusting the distance between the doctor (5) divided in the roller width direction and the water head roller Gα) with the adjustment screw (6). . (7) is a stay that supports the doctor.

FIG. 9 shows another embodiment different from FIG. 7, and in the figure (8)
is a divided doctor, α[ is an adjustment screw that adjusts each doctor, and (9) is a stay that supports these.

Fig. 1θ shows yet another embodiment, in which 0υ is a single-plate doctor and is made of a thin plate of about 1IIII. a3 is /J
Adjustment screws α2 are arranged at S small intervals (same as the above-mentioned split blade width), and α2 is a stay that supports these.

Now, in each of the above embodiments, by operating the adjustment screw, the gap with the solid water base roller (8α) can be controlled, and the amount of water can be arbitrarily adjusted in the width direction of the roller according to the pattern.

Since the present invention is configured as explained in detail above,
In zones α, bSa, d, and e shown in Figure 5, the amount of water required can be controlled according to the respective pattern area ratios, and by controlling this, it is possible to reduce ghosts that cause printing problems and prevent water from penetrating into the ink. As a result, the amount of water flowing can be controlled,
It can be expected that the ink will have a much better gloss after printing. ″

[Brief explanation of the drawing]

Figure 1 is a side view showing the plate cylinder, ink unit, and dampening unit of a conventional offset printing press; Figures 2 and 8 are side views showing conventional examples of the dampening unit, which are different from those in Figure 1. Fig. 5 is an explanatory diagram showing the relationship between the roller width and pattern rate; Fig. 6 is an explanatory diagram showing the relationship between the roller width and water amount; 7 is a side view of a dampening device showing an embodiment of the present invention, FIG. 8(f) is an enlarged plan view of a part of the doctor in FIG. 7, FIG. FIG. 1θ is a side view of a dampening device showing an embodiment of the present invention different from FIG. 7, and FIG. 11 is a diagram showing the relationship between the amount of ink and the amount of water supplied. Explanation of the main parts of the diagram■...The swimsuit is roller 8α...Mizumoto roller (roller with a solid surface) 4...Aquarium 5...Doctor 6...Adjustment screw patent Applicant: Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] In the dampening device of an offset printing press that supplies dampening water to the plate cylinder, among the rollers that make up the dampening device, the gap between the roller and the surface of the roller is divided into multiple parts in the axial direction adjacent to the roller with a solid surface. A dampening device characterized by being equipped with flexible doctors, and the distance between the tip of each doctor and the roller surface can be arbitrarily set. 1