JP3303712B2 - Dampening water removal equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset printing press, and more particularly to an apparatus for removing excess dampening solution from an ink roller surface.

[0002]

2. Description of the Related Art Conventionally, many printing troubles due to dampening water have been known in offset printing, and particularly troubles due to excessive application of dampening water have occurred. For example, as a trouble case due to excessive dampening water, roller baldness (ink does not adhere to the ink roller and the printing density decreases due to insufficient ink transfer amount), plate residue (loss of fluid on the plate due to ink loss) Ink pools on the surface and the ink does not get on it, which reduces the print density), ghosts (shades appear in parts of the picture due to the loss of ink), and drying of the printed matter due to excess dampening water. Due to delay or lack of blistering (the picture part will be blistered with the dryer of the offset rotary press), back cracking / breaking (after drying,
The paper breaks when it is folded by the folding machine), chalking (the printed matter after drying dries in chalk powder forever), set-off (the ink is dried in the stacking state, In addition to the phenomenon of ink being transferred to the back), there are many problems such as poor friction resistance and insufficient gloss of printed matter.

[0003] The cause of such a dampening water excess phenomenon will be described below. As shown in FIG. 3, a conventional offset printing press employs an ink fountain (3) for temporarily storing ink (50).
0) and a watercraft (20) for storing dampening water (60). The ink (50) and the fountain solution (60) reach the plate surface (29) via a plurality of rollers on different routes and merge. Here, the dampening solution (60) uses a water source roller (21) and a plurality of rollers from the watercraft (20) to prevent the ink (50) from reaching the non-image area of the plate surface (29). A uniform and thin water film is passed through the roller (2
A dampening solution (60) is applied to the entire surface of the plate (29) so that it can be formed on the surface of (2).

On the other hand, the ink (50) is an ink fountain (30).
By adjusting the gap formed by the doctor blade-like ink key (31) and the ink source roller (32) in the inside, a mechanism for adjusting the amount of the ink (50) transferred to the entire printing paper surface according to the pattern to be printed is provided. I have. In other words, the ink key (31) is
The doctor blades divided at regular intervals in the roller axis direction are regularly arranged. Each time a picture to be printed is different, the gap between the ink source roller (32) and the ink key (31) can be arranged differently in the roller axis direction.

FIG. 4 schematically shows the above state. FIG. 4 shows an example in which the number of ink keys is divided into four (in an actual offset printing press, the number of ink keys is 20 to 30), and the position A (A) is the amount of ink (50) consumed. Ink (50) on the surface of the ink roller (1) in the case of printing a pattern such that the largest number of images are printed, and the number of images is reduced to positions B (B), C (C), and D (D). The state such as the film thickness is shown. As shown in FIG. 3 again, the ink (50) is applied to the inking rollers (23, 2) for applying the ink (50) to the plate surface (29).
4, 25, 26), the amount of ink (50) applied, that is, the ink film thickness, can be partially adjusted according to the number of ink keys (31) and the width of the ink keys (31) in the axial direction. On the other hand, the dampening solution (60) has a constant water film thickness on the plate surface (29) in the width direction of each roller.

In actual printing, since the ink (50) itself absorbs the dampening solution (60), the ink forming roller (2) is used.
3, 24, 25, 26), the thicker the ink film thickness is, the more the dampening water (60) is absorbed. Therefore, as described above, the ink film thickness varies in the width direction of the ink roller according to the picture. On the other hand, since the dampening solution (60) has a constant water film thickness, the portion A (A) shown in FIG. 4 absorbs a large amount of the dampening solution (60) and the portion D shows a small amount of absorption. Therefore, in a large amount of printing, the dampening solution (60) cannot be completely absorbed at the position D (D), so that there is a surplus. This is an example of an excess of the dampening solution (60), which causes various troubles as described above.

To prove this, the dampening water (60) as shown in FIG. 4 is constant in the width direction of the ink roller (1), and the film thickness of the ink (50) is large at the position A (A). A continuous printing experiment was performed under the condition that the position B (B), the position C (C), and the position D (D) become thinner. The result is shown in FIG.
3 shows changes in the reflection density of each part with respect to the elapsed time of continuous printing. From this result, in the position D (D) where the ink film thickness is the smallest, the excess of the dampening solution (60) increases with time, the print density decrease (decrease in ink transfer amount) increases, and the position C (C) ), The position becomes smaller in the order of the portion B (B), and there is almost no change in the position A (A). That is, while the excess of the dampening water (60) increases with time in the part D, the part A (A) is in a normal state and the ink amount and the dampening water are well balanced. become. If this state continues, the above-mentioned trouble will appear.

As means for solving such a problem, Japanese Patent Application Laid-Open No. 1-163066 discloses a method. According to this proposal, the dampening water droplets are extracted from the ink layer adhering to the surface of the roller by agglomeration due to electrostatic induction when a DC high voltage electric field is formed between the roller and the roller. An apparatus for removing excess dampening water of a printing press, comprising a high-voltage electrode for guiding downward, and the voltage electrode being disposed at a predetermined distance from the roller along the axial direction of the roller. However, by dispersing and emulsifying the fountain solution in the ink to a certain extent, an appropriate ink viscosity and its transferability can be maintained. However, it is not preferable to remove it, and it causes printing failure.

SUMMARY OF THE INVENTION The present invention solves the problem of the above-mentioned trouble caused by excess dampening water (60). It is an object of the present invention to provide a dampening solution removing device for effectively removing water (60).

[0009]

In order to achieve the above object, according to the present invention, first, a plate cylinder (40) of an ink roller group in an offset printing machine is provided.
Means for blowing air along the ink roller axis direction onto the surface of the ink roller covered with the ink (50) film in which at least one dampening solution (60) is mixed near the plate surface (29). And the blowing flow rate of the air ,
Means for adjusting the amount to a preset amount in accordance with the amount of the image portion of the picture to be printed .

Further, in the invention according to claim 2, means for measuring the ambient temperature in the vicinity of the ink roller, means for measuring the ambient humidity, and means for measuring the temperature and humidity by the two means for controlling the blowing air. And a means for adjusting the humidity to an arbitrary value.

Further, in the invention according to claim 3, the means for blowing air along the ink roller axial direction is a damping water removing device which is arbitrarily divided.

[0012]

Embodiments of the present invention will be described below. As shown in FIG. 1, the fountain solution removing device according to the present invention, in the first aspect of the present invention, first uses at least one or more humidifiers near the plate surface of the plate cylinder in the ink roller group (100) in the offset printing press. A control valve (6) that blows air along the axial direction of the ink roller (1) onto the surface of the ink roller (1) covered with an ink film containing water.
(2) equipped with an air blowing unit and means (control unit (1)
1) an air flow control valve (14)), wherein the ink (50) on the surface of the ink roller (1) as shown in FIG. 2 is provided.
The purpose is to remove surface water (60F) that becomes excess dampening water on the surface of the film to prevent printing trouble.

As shown in FIG. 2, the air blowing section (2) is provided with a plurality of blowing holes (2a) so that air is uniformly blown to the surface of the ink roller (1). . Further, as shown in FIG. 1, an air flow control valve (14) is provided, and the control unit (11)
From the air pump (12) and the air flow control valve (1
By controlling 4), a preset air flow rate can always be stably secured.

The flow rate of the air from the air blowing portion (2) is determined by the size of the ink roller (1), the amount of the image portion of the picture to be printed, and the like. In order to affect the transferability and the like, the ink roller (1) is preferably 20 liters per minute or less per minute.

Here, in order to verify the effect of the dampening solution removing device of the present invention, the following experiment was conducted. As shown in FIG. 2, an ink (50) film containing dampening water (60M) absorbed (emulsified) in the ink is formed on the surface of the ink roller (1), and surface water (surplus dampening water) is formed. 60R), the amount of dampening water supplied is adjusted, air is blown along the axial direction of the ink roller (1), and the amount of air blown is connected to an adjustment controller (not shown). The printing experiment was performed by arranging the portion (2) near the surface of the ink roller (1). The results are shown in FIG. 6, FIG. 7, and FIG.

FIG. 6 shows the relationship between the air flow rate and the elapsed printing time. That is, the air flow rate is consciously adjusted during printing. On the other hand, FIG. 7 shows the relationship between the printing elapsed time and the water content of the ink corresponding to FIG. The water content referred to here is the dampening water (60M) absorbed and emulsified in the ink and the surface water (6
0R). Therefore, it means that the surface water (60R) is naturally increased where the water content is naturally high (time zone).

From FIGS. 6 and 7, it can be seen from FIG. 6 and FIG. 7 that when the air flow rate is increased, the surface water (60R) decreases more. That is, a large amount of fountain solution on the surface is removed.

FIG. 8 shows a change in the reflection density of a printed matter corresponding to the above-mentioned elapsed printing time. From this result, the reflection density of the printed matter is high in the time zone where a large amount of surface water (60R) is removed (this value is a normal value), and the reflection density of the printed matter is low in the time zone where the removal amount is small (this value is Is a kind of trouble). That is, if a large amount of printing is performed for a long time in such a low state, various troubles as described in the related art will occur.

According to a second aspect of the present invention, means for measuring the ambient temperature in the vicinity of the ink roller (1), means for measuring the ambient humidity, and spraying based on the measured values of temperature and humidity by the two means. And a means for adjusting the humidity of the air to an arbitrary value.

As shown in FIG. 1, a thermo-hygrometer (16) is provided in the vicinity of an ink roller (1) to be blown with air, and its data is taken into a control unit (11) to obtain a humidity. By controlling the adjusting section (15), the humidity of the blown air is set to an optimum state. In particular, by controlling so as to provide a difference between the humidity near the ink roller (1) and the humidity of the blown air, it is possible to more effectively remove the dampening water (surface water).

According to the third aspect of the present invention, the means for blowing air along the ink roller axial direction is an arbitrarily divided dampening water removing device.

As shown in FIG. 1, a plurality of divided air blowing portions (2, 3, 4, 5) are arranged in the axial direction of the ink roller (1), and a control valve ( 6, 7, 8, 9), from the air pump (12) to the humidity controller (15), the filter (1).
3) The constant air flow supplied through the air flow controller (14) and the pipe (10) is controlled by the control valves (6, 7,.
8 and 9) are used to adjust the variation of the air flow rate for each blowout section. The number of divisions is the size of the printing press,
This is determined in consideration of the number of ink keys and the like, and a uniform air flow is blown in the width direction of the ink roller.

As the roller to be installed at the blowing section of the dampening solution removing device of the present invention, a swing roller (27) on the opposite side of the dampening solution supply device (600) in the ink roller group (100) shown in FIG. Is preferred. This is due to the ink roller where ink accumulation is relatively easy to occur due to a decrease in the ink transfer rate. If a plurality of devices are installed as necessary, the fourth ink on the opposite side of the dampening water supply device (600) is used. The applicator roller (26) is preferred, followed by the oscillating roller (28) on the fountain solution supply device (600) side, followed by the first inker roller (23).

[0024]

As described above, the present invention has the following effects. That is, on the surface of an ink roller covered with an ink film in which at least one dampening solution is mixed near at least one plate surface of a plate cylinder in an ink roller group in an offset printing machine, along the ink roller axial direction. Dampening water comprising an air blowing unit for blowing air and an air flow control unit for adjusting the blowing flow rate of the air to a preset amount according to the amount of the image area of the picture to be printed. The removal device can uniformly and efficiently remove surface water, which becomes excess dampening water, from the surface of the ink film on the ink roller surface, and has the effect of preventing printing trouble due to excessive dampening water.

Further, the dampening device includes means for measuring the temperature and humidity around the ink roller and means for controlling and adjusting the humidity of the blown air to an arbitrary value based on the measured value of the temperature and humidity by the means. The effect that the water removal device can efficiently remove the surface water that becomes the surplus dampening water on the surface of the ink film on the ink roller surface with a more optimal amount without being affected by the temperature and humidity around the printing press. There is.

Further, the damping water removing device is formed by arbitrarily dividing an air blowing portion for blowing air along the axial direction of the ink roller, so that a uniform air can be blown in the width direction of the ink roller to be sprayed. It has the effect of blowing the flow rate.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dampening solution removing device according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a part of a side surface of the dampening solution removing device according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an arrangement of ink rollers and the like of the offset printing press according to the present invention.

FIG. 4 is a schematic diagram for a printing test according to the present invention.

FIG. 5 is a graph showing the results of a printing test according to the present invention.

FIG. 6 is a graph showing a relationship between an air flow rate and an elapsed time in a printing test result on the effect of the present invention.

FIG. 7 is a graph showing the relationship between the water content of the ink and the elapsed time in a printing test result on the effect of the present invention.

FIG. 8 is a graph showing the relationship between paper surface reflection density and elapsed time in a printing test result on the effect of the present invention.

[Explanation of symbols]

 1 {ink roller 2, 3, 4, 5} air blowout section 6, 7, 8, 9 {control valve 2a} blowout hole 10 {air pipe 11} control section 12 {air pump 13} ‥ Air filter 14 ‥‥ Air flow control valve 15 ‥‥ Humidity control unit 16 ‥‥ Temperature / humidity meter 20 舟 Water boat 21 ‥‥ Water roller 22 ‥‥ Wet roller 23 ‥‥ First inking roller 24 ‥‥ 2nd inking roller 25 {third inking roller 26} 4th inking roller 27 {swing roller on opposite side of dampening water supply device 28} swing roller on dampening water supply device 29 Plate surface 30 ‥‥ Ink fountain 31 ‥‥ Ink key 32 元 Ink origin roller 40 ‥‥ Plate cylinder 42 ‥‥ Blanket cylinder 50 ‥‥ Ink 60 ‥‥ Damp water 60M ‥‥ Emulsified dampening water 60 ‥‥ surface water 100 ‥‥ ink roller group 500 ‥‥ ink feeder 600 ‥‥ dampening water feeder A ‥‥ position A portion B ‥‥ position B section C ‥‥ position C unit D ‥‥ position D unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-268644 (JP, A) JP-A-5-269979 (JP, A) JP-A-63-132054 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) B41F 31/02 B41F 33/14

Claims (3)

(57) [Claims] An ink (5) containing at least one dampening solution (60) in the vicinity of a plate surface (29) of a plate cylinder (40) in an ink roller group in an offset printing press.
0) The means for blowing air along the axis of the ink roller to the surface of the ink roller covered with the film and the flow rate of the air are adjusted according to the amount of the image portion of the picture to be printed.
Flip and dampening water removal device, characterized in that it consists of a means for regulating the amount previously set. 2. A means for measuring the ambient temperature in the vicinity of the ink roller, a means for measuring the ambient humidity, and adjusting the humidity of the blown air to an arbitrary value based on the measured values of temperature and humidity by the two means. 2. A fountain solution removing device according to claim 1, further comprising: 3. The fountain solution removing device according to claim 1, wherein the means for blowing air along the axial direction of the ink roller is arbitrarily divided.