JPH03213341A - Gravure printing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a gravure printing method using ultraviolet drying ink.

[Prior Art] In the conventional gravure printing method, a normal ink containing approximately 70% solvent is used, and there is no case where an ultraviolet drying ink is used. The viscosity is kept low by dissolving the binder (binder) in a solvent, and the ink scraping action of the doctor on the plate surface satisfies the ink in the cells of the gravure printing roll, and removes the ink adhering to the edges. Scraping is also done well. Then, the ink filled in the cells is transferred to the printing paper, and when the solvent is evaporated by the drying device, the so-called ink is dried.

[Problems to be Solved by the Invention] However, since the storage and usage methods for regular ink containing about 70% solvent are very strict under the Fire Service Act, it is desired to be able to use ink that does not contain solvent. Additionally, if ink that does not contain solvents can be used, the cause of air pollution will be eliminated.

Furthermore, normal ink contains about 70% solvent.
Marked at 7-1! For example, if the transfer rate of normal ink filled in a cell with a depth of 20 microns is about 50%, the transfer rate of normal ink is approximately 50%. The thickness of the normal ink is 10 microns, but when the solvent evaporates, the thickness of the normal ink becomes 3 microns, which is extremely small compared to the depth of the cells. This is also the reason why net gravure is not able to take full advantage of its enriching features.

As a means for solving the above problems, the present inventors have proposed the following.

When we thought of using ultraviolet dry ink and printed by supplying the ultraviolet dry ink to the ink tray of a rotogravure rotary press, the ink scraping effect with the doctor was extremely poor due to the high viscosity of the ink. Only defective prints could be printed. Therefore, when 5% solvent was added to the ultraviolet-dried ink, the ink scraping condition of the doctor could not be improved, and even when 10% solvent was added, the same result was obtained.

The present invention was devised in view of the above-mentioned points, and it is possible to lower the viscosity of ultraviolet-dried ink, and to maintain the ink scraping condition of the doctor in a good condition equivalent to that of normal ink, thereby making it easier to handle the ink. It is an object of the present invention to provide a gravure printing method that is not subject to the Fire Service Act regulations and that can print extremely thick ink and significantly increase the density gradation.

[Means to solve the problem] According to the present invention, as a means for solving the problem.

According to the present invention, as a means for solving the above problems.

The doctor 3 is installed on the downstream side of the gravure printing roll 1 with its knees facing downward, and the doctor 3 supplies ink within the contact angle to the gravure printing roll 1, and the ink is supplied with ultraviolet drying ink. The gravure printing roll l is heated by an appropriate heating means to maintain the gravure printing roll l at a required temperature, and the printing paper is The object of the present invention is to provide a gravure printing method characterized in that the ultraviolet drying ink transferred to W is dried by an ultraviolet drying device 10 provided along the flow of the printing paper W.

[Operation J The gravure printing roll 1 is heated to a required temperature by the heating means 9 or 11. Therefore, the ultraviolet dry ink supplied within the contact angle of the doctor 3 is also heated, and the viscosity of the ultraviolet dry ink becomes as low as that of normal ink. Therefore, the doctor 3 can scrape off the ultraviolet-dried ink as well as in the case of normal ink. In this way, the ultraviolet-dried ink filled in the cell can be transferred to any point of contact with the compaction roll 2 without increasing its viscosity.
It is transferred to the printing paper W passing between the gravure printing roll 1 and the rolling pressure roll 2. Then, the ultraviolet drying ink transferred to the printing paper W is dried by the ultraviolet rays and heat of the ultraviolet drying device IO, and printing is performed without any trouble.

Look at L. JJIi Inpada Mochi Wζ Soaking and fortifying veins Salmon Yang Ink does not contain volatile solvents, so the thickness of the ink is determined by multiplying the cell depth by the transfer rate. This results in thick printing with almost no change.

[Example] An example of the gravure printing method according to the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the gravure printing method according to the present invention.

First, the configuration will be explained. In the same figure, the symbol 1 is a gravure printing roll, the symbol 2 is a compaction roll, the symbol 3 is a doctor,
Reference numbers 4 and 5 are paper guide rolls. The printing paper W passes between the gravure printing roll 1 and the rolling pressure roll 2, is printed, and is guided to paper guide rolls 4 and 5. The doctor 3 is provided on the downstream side of the gravure printing roll 1, and is in contact with the gravure printing roll 1 at an acute angle with its edge facing downward. An ink tank 6 whose lower part is narrowed into a barrel shape is provided in a space corresponding to the contact angle of the doctor 3 with the gravure printing roll l, and the width provided at the lower end of the ink tank 6 is approximately 1 m
m, a slit 6a whose length is larger than the roll surface length is close to the contact point of the gravure printing roll 1 of the doctor 3,
Ink can be supplied to the contact angle of the doctor 3 with respect to the gravure printing roll 1. This is so that when the gravure printing roll l rotates, the ink can flow out from the slit 6a at the lower end of the ink tank 6 to the gravure printing roll l in a substantially uniform thin film form.

The ink tank 6 is provided with an ink heater 6b, which heats the ultraviolet-dried ink in the ink tank 6 to around 50 degrees Celsius to maintain a low viscosity. Further, the ink tank 6 is supplied with ultraviolet dry ink from a replenishment tank 7.
The ink is also equipped with a preheater 7a, which heats the ultraviolet-dried ink to around 50 degrees Celsius and maintains it at a low viscosity. Therefore, when the valve 8 is opened and ink is replenished from the replenishment tank 7 to the ink tank 6, the ink tank 6
The viscosity of the ultraviolet-dried ink is maintained so that it does not change.

The lower part of the gravure printing roll l faces into a duct 9 installed below, and is heated by hot air flowing through the duct 9 after 50 degrees Cti.

Therefore, the ink filled in the cells of the gravure printing roll 1 is maintained at around 50 degrees Celsius to maintain a low viscosity state. The duct 9 is provided so that the upstream portion thereof can be easily removed in order to allow the gravure printing roll 1 to be removed and replaced.

Along the printing paper W that passes between the gravure printing roll 1 and the compaction roll 2 and is guided by the paper guide rolls 4 and 5, on the side of the printing paper W on which the ink is transferred. , UV (ultraviolet light) is used as an ultraviolet drying device for drying the ultraviolet drying ink printed on the printing paper W.
A plurality of light sources 10 are provided.

The ink used is an ultraviolet drying ink that is commonly commercially available and used for printing labels and the like. The ultraviolet drying ink is
Consists of pigment and liquid resin. The ultraviolet drying ink usually does not contain any solvent.The liquid resin as a component of the ultraviolet drying ink has a molecular weight of, for example, 3000 to
It has a high viscosity of 0.000 cm voids, and when heated to around 501 tC, it becomes a low viscosity of, for example, 3 to 5 cm voids, making it difficult to dry with heat ray drying.It has a low degree of polymerization and easily reacts synergistically with ultraviolet rays and heat to harden and dry. have

Next, the action will be explained.

The ultraviolet drying ink in the supply tank 7 is heated by the preheater 7.
After being heated to 50 degrees C# by A, the ink is maintained at a low viscosity of 3 to 5 centimeter voids, which is equal to or lower than that of ordinary ink. and,
When the valve 8 is opened, the ultraviolet drying ink in the supply tank 7 flows down into the ink tank 6. The ultraviolet-dried ink in the ink tank 6 is continuously heated by the ink heater 6b.
The viscosity is maintained at a low level by heating to around 30°C. The ultraviolet-dried ink in the ink tank 6 is supplied from the three-way roller a at the lower end of the tank to the vicinity of the contact point of the doctor 1 with the gravure printing roll 1, and is immediately subjected to the ink scraping action of the doctor 3. . The doctor 3 is brought into contact with the rotating gravure printing roll 1 under a predetermined pressure and produces an ink scraping action, thereby scraping off the ultraviolet-dried ink that adheres to the gravure printing roll l and tries to rotate with it above the doctor 3. , the cells of the gravure printing roll l are filled with ultraviolet drying ink. In this case, the ultraviolet-dried ink adhering to the gravure printing roll l is heated to around 50 degrees Celsius and maintained at a low viscosity of 3 to 5 centimeter voids, which is equivalent to or lower than normal ink, so the doctor 3 is equivalent to that of normal ink. The ink can be scraped off well, and the ultraviolet-ray-dried ink can be applied only to the cells of the gravure printing roll l. Since the gravure printing roll l is heated by the hot air flowing through the duct 9 and the surface temperature of the ultraviolet drying ink applied to the cell is maintained at 50 degrees, the ink is maintained at the same low viscosity and remains in the cell. The viscosity does not increase, and the ultraviolet-dried ink filled in the cell transfers to the printing paper W passing between the gravure printing roll 1 and the compaction roll 2 in a manner similar to that of normal ink. It will metastasize at a rate. Subsequently, the ink transferred to the printing paper W is
It is dried by ultraviolet light and heat from a UV light source IO. In this way, the ultraviolet drying ink printed on the printing paper W does not contain volatile solvents, so the thickness of the ink transferred to the printing paper is the value obtained by multiplying the cell depth by the transfer rate, and there is almost no change. This will result in thick printing.

FIG. 2 relates to a second embodiment of the gravure printing method according to the present invention.

In this embodiment, a plurality of rod-shaped heaters 11 are arranged in parallel under the gravure printing roll 1 as heating means to heat the gravure printing roll 1, and this is the only difference from the first embodiment described above. However, since other parts are the same, they are given the same reference numerals as in FIG. 1 and their explanation will be omitted.

Note that the present invention does not imply that UV-dried ink should not contain a solvent.1 Unlike regular ink, UV-dried ink is impregnated with a solvent to play the role of ink transfer and drying. It has little significance.

It is assumed that the infrared light source 7 is capable of heating the gravure printing roll 1 so that the surface temperature during operation becomes 50 degrees. The infrared light source 7 is provided so that it can be easily moved or removed so that the gravure printing roll 1 can be removed and replaced.

[Effects of the Invention] According to the gravure printing method of the present invention described above, ■ Since the gravure printing roll is heated to lower the viscosity of the ultraviolet-dried ink to the same level as normal ink, it is easy to remove the ink from the doctor. It can be maintained in good condition and printing can be performed without any problems.

■Since UV-dried ink is used and does not contain solvents, the handling of ink is not subject to fire regulations, and the problem of air pollution can be resolved.

■Using ultraviolet drying ink and having no volatile matter, it is possible to print extremely thick ink, and the density gradation, which is a characteristic of net gravure, can be significantly increased, thereby dramatically improving the quality of printing. When the method of the present invention was carried out and printed using a printing proofing machine, high-quality printing with large ink buildup and extremely high density gradation was achieved, as could be seen by the touch.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of the main parts of a first embodiment of the gravure printing method of the present invention. FIG. 2 is a schematic side view of the main parts of a second embodiment of the gravure printing method of the present invention. l...Gravure printing roll, 2...φ compaction roll. 3e... Doctor 7... Fist heater 9 - O fist heating means, lO... - Ultraviolet drying device. 1111 Φ heating means, W... paper to be printed.

Claims (1)

[Claims] A doctor is installed on the downstream side of the gravure printing roll with its edge facing downward, and ink is supplied within the contact angle of the doctor with the gravure printing roll. The printing roll is heated by an appropriate heating means to maintain the gravure printing roll at the required temperature, and the ultraviolet drying ink transferred to the printing paper when passing between the gravure printing roll and the compaction roll is removed. A gravure printing method characterized by drying using an ultraviolet drying device installed along the flow of printing paper.