JPH04250039A - Wetting device of offset rotary press - Google Patents

Abstract

PURPOSE:To improve the print quality of an offset rotary press and also simplify the structure so that the feed of wetting water becomes stable. CONSTITUTION:Compressed air is supplied to a wetting water tank 16a and thereby the interior of the wetting tank 16a is pressurized. In addition, a solenoid valve for wetting water 10a and a solenoid valve for compressed air 10b are operated using a solenoid valve control device 12 and at the same time, a pressurized wetting water 16b is ejected to each cubic body 7 through each nozzle 6 from the wetting water tank 16a so that the wetting water 16b becomes fine droplets. Further, the fine droplets of the wetting water 16b are sprayed in the form of mist to a roller 5 through each slit spray nozzle 13 provided on the front of spray cover 8. Subsequently the mist lands on the roller 5. In addition, this wetting water 16b is transferred to a watering roller 4 and then to the plate 2 of a plate cylinder 1 so that a watery film is formed on the plate 2 to prevent ink from sticking to the non-image line part of the plate 2. The wetting water of large grain diameter which has not turned to fine particles even after running into the cubic body 7 is discharged to an area outside the wetting device through a drain pipe 9 on the spray cover 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dampening device for an offset rotary printing press.

0002

[Prior Art] A conventional spray dampening device for an offset printing press will be explained with reference to FIGS. 3 and 4. 1 in FIG. 3 is a plate cylinder;
2 is a plate attached to the outer peripheral surface of the plate cylinder 1, 3 is a blanket cylinder, 4 is a bathing roller, 5 is a water reciprocating roller, 16a is a dampening water tank, 16b is a dampening water, 17 is a dampening water control device ,1
8a is a spray bar.

Further, in FIG. 4 showing details of the spray bar 18a, 18b is a plurality of nozzles arranged in the roller width direction, 19 is an inner cylinder, 20 is a piston (valve body), and 21
are the same number of electromagnetic switching valves as the nozzles controlled by the dampening water control device 17, and 22 is a spring. In the spray-type dampening device of the offset printing press shown in FIGS. 3 and 4 above, the dampening water control device 17 operates the electromagnetic switching valve 21 to move the piston (valve body) 20 up and down, so that the upper end of the inner cylinder 19 While opening and closing the dampening water outlet provided in the dampening water outlet, the dampening water 16b in the dampening water tank (hydraulic tank) 16a is sprayed from inside the spray bar 18a → inside the inner cylinder 19 → from the nozzle 18b to the water reciprocating roller 5, The water is applied to the reciprocating roller 5, and then the water is transferred from the reciprocating roller 5 to the swimsuit roller 4 to the plate 2 of the plate cylinder 1, forming a water film on the surface of the plate 2, and ink to the non-image areas of the plate 2. Prevents adhesion of

The amount of dampening water adhering to the plate 2 of the plate cylinder 1 is controlled by the ON time (outlet opening) of the dampening water control device 17 and the number of times the piston 20 moves up and down (n times/second).

[0005]

[Problems to be Solved by the Invention] In the spray type dampening device of the conventional offset printing press shown in FIGS. Therefore, the dampening water 16b is intermittently sprayed to control the amount of water, which causes the following problem. That is, (1) There is variation in the strength of the spring 22 of each nozzle 18b, and the amount of jetted water is not the same in the roller width direction. In addition, there are variations in the spray state of the dampening water 16b sprayed from each nozzle 18b, and the water amount distribution becomes uneven in the roller width direction (excess or deficiency occurs in the amount of water supplied to the roller), resulting in a decrease in printing quality. do. (2) Changes in water pressure cause changes in the spray state and water droplet diameter of the dampening water 16b sprayed from each nozzle 18b. (3) Since the installation location of each nozzle 18b is inside the edge of the second surface of the plate, the dampening water at the edge of the plate 2 tends to be insufficient, and the dampening water is not uniformly supplied over the entire area in the width direction of the roller. There was a problem.

The present invention has been proposed in view of the above-mentioned problems, and its purpose is to improve printing quality. Another object of the present invention is to provide a dampening device for an offset rotary printing press that can stably supply dampening water and has a simplified structure.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the dampening device for an offset rotary printing press of the present invention includes a spray bar having a plurality of nozzles arranged along the width direction of the roller, and each of the above-mentioned spray bars. A plurality of dampening water atomizing members arranged in front of the nozzle, each nozzle and the dampening water atomizing member are separated by a partition wall, and a slit-shaped spray port is provided along the width direction of the roller on the front surface. A spray cover, a pressurized air supply system connected to the spray cover, a dampening water supply system connected to each of the above nozzles, and a solenoid valve installed in the pressure air supply system and the dampening water supply system to open and close them. and a solenoid valve control device.

[0008]

[Operation] The dampening device of the offset rotary printing press of the present invention is constructed as described above, and pressurized air is supplied to the dampening water tank to pressurize the inside of the dampening water tank. In addition, the solenoid valve control device opens and closes the solenoid valve for dampening water and the solenoid valve for pressurized air, and sprays the pressurized dampening water in the dampening water tank from each spray nozzle to each sphere. At the same time, pressurized air from a pressurized air supply source is injected into each compartment of the spray cover, and the atomized dampening water is sprayed from each slit-shaped spray port provided on the front of the spray cover to the roller. Spray it on the roller and let it adhere to the roller. Additionally, this dampening water is transferred from the wet roller to the plate on the plate cylinder, forming a water film on the plate surface to prevent ink from adhering to the non-image areas of the plate. Also, dampening water with large particles that are not atomized even after colliding with the spheres is discharged from the dampening device through the drain pipe of the spray cover and collected.

[0009]

[Embodiment] Next, the dampening device of the offset rotary printing press of the present invention will be explained with reference to an embodiment shown in FIGS. 1 and 2. In FIG. 3 is the blanket cylinder, 4 is the swimsuit roller, 5 is the water reciprocating roller, 6
7 is a plurality of spray nozzles, 7 is a plurality of spheres (dampening water atomization member) arranged in front of each spray nozzle 6, 8
is a spray cover, and the spray nozzles 6 and the spheres 7 are arranged in the width direction of the water reciprocating roller 5 within the spray cover 8. This spray cover 8 is partitioned into a plurality of chambers by partition walls, and each of the spray nozzles 6 and each of the spheres 7 are housed in each of these chambers. 2 are a plurality of slit-shaped spray ports 13 provided on the front surface of the spray cover 8, and the slit-shaped spray ports 13 are lined up in the width direction of the water reciprocating roller 5.

Further, 9 in FIG. 1 is a drain pipe provided in the spray cover 8, 12 is a solenoid valve control device, 16a is a dampening water tank, 16b is dampening water, and 14a is a pressure air supply source (not shown). a plurality of spraying pressurized air supply pipes extending from the spray cover 8 into each partition chamber of the spray cover 8; a pressurizing pressurized air supply pipe 14b extending from a pressure air supply source (not shown) into the dampening water tank 16a; 15 is the dampening water tank 16a
A plurality of dampening water supply pipes extending from inside to each of the spray nozzles 6, 10a a plurality of solenoid valves for dampening water provided in each dampening water supply pipe 15, and 10b a plurality of dampening water supply pipes for each spraying 1
4a is a plurality of pressure air solenoid valves, 11a is a pressure air signal cable extending from the solenoid valve control device 12 to each of the pressure air solenoid valves 11b, and 11b is a pressure air signal cable extending from the solenoid valve control device 12 to each of the pressure air solenoid valves 11b. This is a dampening water signal cable extending to the dampening water solenoid valve 10a.

Next, the operation of the dampening device of the offset rotary printing press shown in FIGS. 1 and 2 will be explained in detail. Pressurized air is supplied from the spray pressurized air supply pipe 14a to the dampening water tank 16a to pressurize the inside of the dampening water tank 16a. Also, while the solenoid valve control device 12 opens and closes the dampening water solenoid valve 10a and the pressurized air solenoid valve 10b, the dampening water tank 16 is opened and closed.
The pressurized dampening water 16b in a is sprayed from the dampening water supply pipe 15 → each spray nozzle 6 → each sphere 7 to atomize the dampening water 16b, and at the same time, the pressurized air from the pressure air supply source is Pressure air supply pipe 14a for spraying is injected into each compartment of spray cover 8, and atomized dampening water 16b is sprayed from each slit-shaped spray port 13 provided on the front surface of spray cover 8 to water reciprocating roller 5. The water is sprayed onto the water reciprocating roller 5. In addition, this dampening water is transferred from the swimsuit roller 4 to the plate 2 of the plate cylinder 1, and a water film is formed on the plate 2 surface.
Prevent ink from adhering to non-print areas. Further, dampening water with large particles that are not atomized even after colliding with the sphere 7 are discharged out of the system from the drain pipe 9 of the spray cover 8 and collected.

0012

[Effects of the Invention] The dampening device of the offset rotary printing press of the present invention supplies pressurized air to the dampening water tank as described above.
Pressurize the dampening water tank. In addition, the solenoid valve control device opens and closes the solenoid valve for dampening water and the solenoid valve for pressurized air, and sprays the pressurized dampening water in the dampening water tank from each spray nozzle to each sphere. At the same time, pressurized air from a pressurized air supply source is injected into each compartment of the spray cover, and the atomized dampening water is sprayed from each slit-shaped spray port provided on the front of the spray cover to the roller. Since the ink is sprayed onto the rollers, it does not cause water marks (when the water droplets are large, they are not completely spread between the rollers, resulting in localized ink transfer defects and water marks that come off as white). , printing quality can be improved.

In addition, the dampening water sprayed from each nozzle collides with the sphere and becomes atomized, and the atomized dampening water is then sprayed by pressurized air from each slit-shaped spray port provided on the front surface of the spray cover. Since it is sprayed onto the roller, dampening water can be uniformly supplied to the entire width of the roller.
Print quality can also be improved from this point of view. Further, the above-mentioned effect can be achieved even if the orifice diameter of the nozzle is large, and the nozzle is less likely to be clogged with foreign matter and dampening water can be stably supplied. In addition, changes in the spray pattern and water droplet diameter due to fluctuations in the dampening water supply pressure can be ignored, which has the effect of simplifying the structure of the dampening device.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of a dampening device for an offset rotary printing press according to the present invention.

2 is a front view of each slit-shaped spray port on the front surface of the spray bar as seen from the direction of arrow A in FIG. 1; FIG.

FIG. 3 is a system diagram showing a spray type dampening device of a conventional offset printing press.

FIG. 4 is a longitudinal side view showing a spray bar of the spray dampening device.

[Explanation of symbols]

5 Roller 6 Nozzle 7 Dampening water atomization member (sphere) 8
Spray cover 12 Solenoid valve control device 10a Solenoid valve for dampening water 10b Solenoid valve for pressurized air 16a Dampening water tank 16b Dampening water 18a Spray bar

Claims (1)

[Claims] [Claim 1] A spray bar having a plurality of nozzles arranged along the width direction of the roller, a plurality of dampening water atomizing members arranged in front of each nozzle, and each nozzle and dampening water atomization member. a spray cover in which the conversion member is partitioned by a partition wall and a slit-shaped spray port is provided along the roller width direction on the front surface; a pressurized air supply system connected to the inside of the spray cover;
An offset rotary press comprising a dampening water supply system connected to each of the nozzles, and a solenoid valve control device for controlling opening and closing of solenoid valves provided in the pressurized air supply system and the dampening water supply system. Printing press dampening device.