JP4986448B2 - Offset printing machine equipped with dampening water removing device and roller air cooling device, printing method and use thereof. - Google Patents

Description

  The present invention relates to offset printing using a fountain solution removing device, and more particularly to an offset printing machine and printing method that enable stable printing without using a temperature control device in a roller.

  In offset printing, a plate consisting of an oleophilic image area that accepts oil-based ink and a hydrophilic non-image area that accepts dampening water is used to form an image on the plate surface using the repulsion between oil-based ink and water. And a printing method for transferring to a printing medium through a blanket cylinder. Here, if the distribution of the image area and the non-image area is biased, the supply balance of the ink and the dampening water tends to be lost, and a lot of printing troubles occur. If the amount of fountain solution supplied is excessive, problems such as roller peeling, plate residue, tinting, ghosting, blistering, choking, set-off, blocking, friction resistance, and poor gloss will occur. If the supply amount is too small, there is a problem that image formation is not sufficient and scamming occurs. Since considerable skill is required to adjust the supply amount of the fountain solution, printing is generally performed in a state where the fountain solution is excessive.

  As means for solving the above problems, Patent Document 1 discloses that means for blowing air along the ink roller axial direction and the air blowing flow rate are set in advance according to the amount of the image line portion of the pattern to be printed. There is disclosed a dampening water removing apparatus characterized by comprising means for adjusting.

  Further, Patent Document 2 is provided with a flexible pipe having a plasticity that blows out air toward the contact portion on the entrainment side of the ink kneading intermediate roller in which surplus water of the dampening water of the offset printing press easily accumulates. A dampening water adjusting device for an offset printing machine is disclosed, in which a plurality of pipes are arranged in the direction of the generatrix of the roller, and each of the free pipes is provided with an adjusting valve for adjusting the flow rate of air.

  On the other hand, the offset printing press is intended to supply stable ink and fountain solution, and is provided with a cooling device as means for maintaining a constant film thickness of the ink and fountain solution. In the ink section, a device for circulating cold water in the roller is provided to adjust the roller temperature, and in the water supply section, the temperature of dampening water supplied is generally set low. However, in a roller cooling device using water flow, it frequently occurs that the water flow pipe is clogged due to the occurrence of rust or the like, and water does not circulate. Furthermore, there is a problem that the apparatus and operation cost are expensive. On the other hand, if it is cooled too much, condensation will occur and problems such as reverse trapping and paper breakage will occur due to dripped water.

Japanese Patent No. 3303712 JP 2004-160954 A

  The technique disclosed above is for removing excess dampening water on the surface of the ink roller. However, since air is blown to the contact portion on the ink roller axial direction or the entrainment side of the ink roller, the ink surface is moistened. The water was not able to be evaporated effectively, and a large amount of air was required. An object of the present invention is to effectively remove excess dampening water using air in offset printing, and to obtain a stable high-quality printed matter without using a temperature control device in a printing press roller. In this invention, the dampening water removal apparatus which can remove excess dampening water using air effectively is provided. Moreover, the offset printing method which can obtain the stable high quality printed matter using this dampening water removal apparatus, without using the temperature control apparatus in a printing press roller is provided.

In order to solve the above-mentioned problem, the present inventor, in an offset printing method that does not use a temperature control device in a printing press roller, in an ink roller covered with an ink film mixed with fountain solution, the tangential rotation order of the ink roller. In order to complete the present invention, it has been found that printing performance is excellent when using an offset printing machine having means for spraying air in the direction and means for spraying air on both ends of the ink roller. It came.

The invention according to claim 1 is an apparatus for spraying air to remove excess dampening water, wherein an object to be sprayed with air is an ink roller covered with an ink film mixed with water, Air is blown from the nozzle in the tangential direction of the ink roller and the forward direction in the rotation direction of the ink roller to the portion other than the contact portion between the ink roller and the adjacent ink roller, and the air is directed in the axial direction of the ink roller. A surplus fountain solution removing device, which spreads in a plane within a parallel plane . That is, the only multiplied blowing air from a tangential rotational forward of the ink roller, the air is by spreading on the surface shape in the plane parallel to the axial direction of the ink rollers, and effectively vaporize the excess dampening water in the air It is possible to remove it.

  The invention according to claim 2 is an offset printing machine provided with the excess dampening water removing device according to claim 1 and capable of continuously supplying stable ink and dampening water. I will provide a.

The invention according to claim 3 is the offset printing machine according to claim 2, further comprising means for blowing air to both end support portions of the ink roller .

The invention according to claim 4 is characterized in that the means for spraying air on the ink roller and the means for spraying air on both ends of the ink roller are arbitrarily divided. It is an offset printing machine .

The invention according to claim 5 is the offset printing machine according to any one of claims 2 to 4 , wherein the nozzle has a flat spray pattern .

The invention according to claim 6 is the offset printing machine according to any one of claims 2 to 5, wherein an adjustment valve for adjusting the flow rate of air is provided .

The invention according to claim 7 is an offset printing method using the offset printing machine according to any one of claims 2 to 6 .

  According to the present invention, since excess dampening water can be removed by evaporation on the surface of the ink roller covered with the ink film mixed with dampening water, it is stable without impairing the transferability of the ink in the ink fountain roller and transfer roller. This makes it possible to supply the ink, and helps the operator to lack the skill of adjusting the dampening water supply. At the same time, it has a humidifying effect.

  In addition, the ink roller and the bearing portion are prevented from retaining the heat of vaporization accompanying the evaporation of the excess dampening water on the surface of the ink roller covered with the ink film mixed with the dampening water and the both-end support portion atmosphere of the ink roller. As a result, the temperature rise due to the friction is drastically suppressed, the temperature adjusting device with a built-in roller becomes unnecessary, and the cost of equipment, power, etc. is reduced.

  Furthermore, since excess dampening water in the ink is removed and air is supplied to the inside, the drying property, friction resistance, and the like of the ink having oxidative polymerization properties are improved, and a high-quality printed matter can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of an ink roller or the like of an offset printing press equipped with an excess dampening water removing device 1 in an embodiment of the present invention, and shows the positional relationship between the ink roller and means for spraying air. In FIG. 1, ◯ represents a metal or / and hard resin roller, and ◎ represents a rubber roller.

  The mounting position of the means for blowing air of the present invention is selected in consideration of not hitting the plate surface and the water supply device at the point where the air is blown out. It is preferable to attach in the position which does not inhibit the dampening water supply from the water supply apparatus 20. FIG. Further, the ink roller to which the means for blowing air is attached is preferably selected from the roller that is the swing roller 10. The roller 10a shown in FIG. 1 is particularly preferable from the viewpoint of installation space and roller rotation direction. A means for selecting a plurality of rollers and blowing air may be attached.

  FIG. 2 is a schematic side view of the embodiment of the present invention, and shows the positional relationship between the means for blowing air to the ink part of the printing press ink roller and the means for blowing air to the both end support parts of the ink roller. The ink roller both ends supporting portion refers to the supporting shaft portion 6 extending from both ends of the ink roller to the bearing.

  As shown in FIG. 2, an air pipe 5 is installed in parallel with the ink roller 10a, and an adjustment valve 4b capable of adjusting the flow rate of air is attached to the air supply pipe 7. The air pipe is provided with an adjustment valve 4a capable of adjusting the air flow rate and a plurality of hoses 3 provided with nozzles 2 at the ends. The plurality of nozzles 2 a at both ends of the air pipe are attached so as to blow air toward the ink roller both ends support 6. The plurality of nozzles 2b at the center of the air pipe are attached so as to blow air from the tangential direction on the surface of the ink roller 10a.

  FIG. 3 is a schematic cross-sectional view of the ink roller portion of the embodiment of the present invention, and shows the positional relationship between the ink roller 10a and the means for blowing air in detail. A hose 3 extending from the air pipe 5 fixes the position of the nozzle 2 in the tangential direction of the ink roller 10a. The hose 3 can be freely bent, and the nozzle position can be adjusted in the tangential direction of the ink roller according to the image line condition of printing.

  In the present invention, a nozzle having a flat spray pattern is used. Examples of the flat spray pattern include flat spray, L-shaped flat spray, curtain spray, and elliptical spray. A commercially available nozzle can be used as long as it has these spray patterns. When a large number of air outlets are provided, the nozzle position can be appropriately adjusted in the swing direction in accordance with the image line condition of printing, and thus flat spray, L-type flat spray, and elliptic spray are particularly preferable.

FIG. 4 is a schematic side view of the blowout air side of the ink roller portion of the embodiment of the present invention, showing a state where air is blown out from the nozzle 2b at a wide angle and sprayed from the tangential direction on the surface of the ink roller 10a. The halftone dot part is the air flow part blown out.

  It is preferable that the air flow portions blown out from the adjacent nozzles 2b intersect on the surface of the ink roller 10a because the excess wet water can be uniformly evaporated in the printed image portion and the water can be evaporated. However, when the ink roller is a swing roller, it is not always necessary for the air flow portions to intersect at the surface of the ink roller in consideration of the left and right moving distance.

FIG. 5 is a schematic cross-sectional view of the blown air of the ink roller part of the embodiment of the present invention, in which the air blown from the nozzle 2b at a narrow angle is blown from the tangential direction to the ink roller 10a covered with the ink layer 8. Represents. The halftone dot part is the air flow part blown out.

  FIG. 6 is a schematic side view of the blowout air side of the ink roller both ends support part of the embodiment of the present invention, and represents a state where air blows out from the nozzle 2a at a narrow angle and blows air on the ink roller support part 6. . The halftone dot part is the air flow part blown out.

  FIG. 7 is a schematic cross-sectional view of the blowout air of the ink roller both ends supporting portion of the embodiment of the present invention, and shows a state where air blows out from the nozzle 2a to a wide angle and blows air on the ink roller supporting portion 6. The halftone dot part is the air flow part blown out. As shown in FIG. 7, the spray pattern and position of the nozzle are set so that air is sprayed onto the support shaft at the ink roller both ends support portion.

  As shown in FIG. 2, an adjustment valve 4b that adjusts the flow rate of air is provided in a pipe that sends compressed air to the air pipe. When printing conditions such as printing paper, printed image line density (density), printing speed (rotation speed), etc. are standard, the regulating valve is used with the valve fixed to the standard. The adjustment valve at the standard time of printing conditions is fixed so that the temperature of the printing roller becomes an air flow rate that does not change with time of printing. When the air flow rate is excessive, proper viscoelasticity is impaired due to ink misting or excessive cooling on the ink roller, and good printing cannot be performed. If the air flow rate is too low, not only the excess dampening water can be removed, but also the roller cooling effect is low, so that stable printing cannot be performed. Therefore, when the printing conditions deviate from the standard, the air flow rate is adjusted by the adjusting valve. More preferably, it can be closed when printing is stopped, and can be ejected and shut off in conjunction with the operation of the printing press.

  In the present invention, in order to effectively evaporate excess dampening water and remove it into the atmosphere, it avoids steam from getting into the roller rotating printing part where the safety cover is installed, and an opening is provided in the upper part of the enclosure or ventilation A good safety cover is desirable.

  In the present invention, ink or fountain solution that is usually used in offset printing can be used. In addition, since excess dampening water can be removed sufficiently, it becomes possible to raise the set temperature of the ink roller than usual, and ink and dampening water can be newly adjusted and used according to the changed temperature conditions. Is possible. Further, it is desirable that the fountain solution used at this time has a low odor.

  The air used in the present invention may be compressed air obtained with a normal air compressor. In order to effectively and stably remove excess dampening water, it is desirable to dry the air with a dryer.

Next, the present invention will be described more specifically with reference to examples and comparative examples.
Example 1
The printing machine is Lithlon 440 (offset sheet-fed printing machine manufactured by Comori Corp.), spraying dry air from nozzles having a flat spray pattern on the tangential direction of the ink roller 10a and both end support portions of the ink roller to supply water The dampening water temperature of the part was cooled to 15 ° C., and 5,000 sheets were printed. As printing conditions, the printing speed was 8000 sph, and Kikuzen coated paper 104.7 g / m ² (trade name: OK Top Coat +; manufactured by Oji Paper Co., Ltd.) was used. The ink was NS New Cell Boate (manufactured by Tokyo Ink Co., Ltd.). The fountain solution used was CDS-903 (manufactured by Tokyo Ink Co., Ltd.) diluted to 2% with tap water. The printing press was set with a constant ink feed and water feed without using a temperature control device in the ink roller.

Performance Evaluation Test The following items were evaluated for Examples and Comparative Examples. The evaluation was performed using a total of 6 prints at the 500, 1000, 2000, 3000, 4000, and 5000 start prints. Regarding the ink roller temperature change, the roller surface temperature was measured with a radiation thermometer and the fluctuation was evaluated.

<Concentration>
The printed matter density of the solid (100%) printing part was visually evaluated according to the following criteria.
3: Small fluctuation.
2: Medium fluctuation (a level that causes no problem in practical use).
1: Large fluctuation (level that causes a problem in practical use).

<Halftone dot shape>
The shape of the 45% halftone dot printed part was visually evaluated according to the following criteria.
3: Good shape with no void and dot gain.
2: Clear and dot gain is present (a level that causes no problem in practical use).
1: Unsatisfactory, dot gain is bad and shape is bad (practical problem level).

<Pseudo drying>
Using a four-color overlap (400%) printing section as a sample, using an automatic ink set testing machine (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the degree of ink adhesion to the coated paper is observed, and it is necessary until the ink does not adhere. Time (minutes) was measured. The shorter this time, the better the pseudo drying property.

<Drying>
The time required for the ink to not adhere to the paper after observing the degree of ink adhesion to the sulfuric acid paper using a C-type drying tester (Toyo Seiki Seisakusho Co., Ltd.) using a four-color overlap (400%) printed part as a sample. (Time) was measured. The shorter this time, the better the drying property.

<Stability of printing>
The fluctuations of the solid (100%) printed portion and the 45% halftone printed portion were relatively visually evaluated and indicated by the following criteria.
A: The fluctuation is small.
○: Medium fluctuation (a level where there is no practical problem).
X: Large fluctuation (level causing a problem in practical use).

<Ink roller temperature change>
Next, evaluation criteria are shown.
A: The fluctuation is small.
○: Medium fluctuation (a level where there is no practical problem).
X: Large fluctuation (level causing a problem in practical use).

Evaluation Results Table 1 shows the evaluation results of Example 1. In Example 1, stable printing was maintained and good printed matter was obtained.

Example 2
Printing similar to Example 1 was carried out except that the dampening water temperature of the water supply unit was 20 ° C. The evaluation results are shown in Table 1. Stable printing was maintained and good printed matter was obtained.

Example 3
Printing was carried out in the same manner as in Example 1 except that air was not blown onto the both ends of the ink roller. As shown in Table 1, good printed matter was obtained.

Example 4
Printing was carried out in the same manner as in Example 1 except that air was blown in the ink roller tangential direction from the hose without using the nozzle 2b. As shown in Table 1, good printed matter was obtained.

Comparative Example 1
Printing was performed in the same manner as in Example 1 except that the regulating valve was closed and no air was sprayed onto the ink roller. The evaluation results are shown in Table 1. A decrease in the density of the printed material was confirmed from the 3000th sheet, the printing conditions were not stable, and good printing was not sustained.

Comparative Example 2
Printing was performed in the same manner as in Example 1 except that the nozzle 2b on the ink roller side was set in the ink roller axial direction. The evaluation results are shown in Table 1. Since the air diffused and hit the water supply unit (water supply device), the dampening water supply was not stable, and good printing was not possible.

  In offset printing, it can be used as a stable printing method that can obtain a good print at low cost.

It is a cross-sectional schematic diagram of the ink roller part of the offset printing machine which attached the excessive dampening water removal apparatus in the Example of this invention. It is a side surface schematic diagram of the Example of this invention. It is a cross-sectional schematic diagram of the Example ink roller part of this invention. It is a blowing air side surface schematic diagram of the Example ink roller part of the present invention. It is a blowing air cross-sectional schematic diagram of the ink roller part of the Example of this invention. It is a blowing air side surface schematic diagram of the ink roller both ends support part of the Example of this invention. It is a blowing air cross-sectional schematic diagram of the ink roller both ends support part of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Excess dampening water removal apparatus 2a, 2b Nozzle 3 Hose 4a, 4b Control valve
5 Air pipe 6 Ink roller support shaft 7 Air supply pipe 10a, 10b, 10c, 10d Ink shaking roller 20 Water supply device 21 Dampening water 30 Plate cylinder 40 Ink fountain roller 50 Ink fountain 60 Ink transfer roller

Claims (7)

A device that blows air to remove excess dampening water,
The target to blow air is an ink roller covered with an ink film mixed with water,
For the portion other than the contact portion between the ink roller and the adjacent ink roller,
Air is blown by a nozzle from the tangential direction of the ink roller and the forward direction in the rotation direction of the ink roller,
The apparatus for removing excess dampening water, wherein the air spreads in a planar shape in a plane parallel to the axial direction of the ink roller .   An offset printing machine comprising the apparatus according to claim 1.   The offset printing machine according to claim 2, further comprising means for blowing air onto both end support portions of the ink roller.   4. The offset printing machine according to claim 3, wherein the means for spraying air on the ink roller and the means for spraying air on both end support portions of the ink roller are each arbitrarily divided. The offset printing machine according to claim 2 , wherein the nozzle has a flat spray pattern .   The offset printing machine according to any one of claims 2 to 5, wherein an adjustment valve for adjusting the flow rate of air is provided. The offset printing method using the offset printing machine in any one of Claims 2-6.

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