JP2003205592A - Gravure printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gravure printing method which can make the same the diameter of all printing rolls to be fitted to each unit in a multicolor gravure rotary printing press of a unit type, and moreover can ensure the tension of a web almost over the full length of a printing line so as to enable execution of excellent printing. <P>SOLUTION: A roll matrix is made of aluminum as to the rearmost printing roll of the gravure rotary printing press, and the roll is thermally expanded by heating to a required temperature so that it has the required diameter. Consequently, a running speed at which the printing roll and an impression cylinder cooperate to pull the web, a printing object, and to make it run is made larger in a required degree than the running speed at which the printing rolls and the impression cylinders of the press other than the rearmost ones cooperate to pull the web and make it run, so that the tension of the web almost over the full length of the printing line be ensured for printing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can make the diameter of all printing rolls mounted in each unit the same in a unit type multicolor printing machine, for example, a gravure rotary printing machine for four-color printing or ten-color printing. Moreover, it is possible to secure the tension of the web over almost the entire length of the printing line and perform good printing, and further, it is possible to reduce the drying load of the last row unit when printing, not the last row unit of the gravure rotary printing press. The present invention relates to a printing roll gravure printing method capable of performing necessary and sufficient ink drying and avoiding a decrease in printing speed even if the drying capacity of the dryer in the last row unit is not large.

[0002]

2. Description of the Related Art Conventionally, gravure printing performed by a unit type multicolor gravure rotary printing machine is
The diameter of the printing roll to be mounted on the printing machine becomes slightly larger as the arrangement order goes to the downstream side. Specifically, the diameter of the printing roll mounted on the printing machine of the second unit is, for example, 10 μm larger than the diameter of the printing roll mounted on the printing machine of the first unit, and the printing roll mounted on the printing machine of the third unit. Has a diameter larger than the diameter of the printing roll mounted on the printing machine of the second unit by, for example, 10 μm. This is because the film is stretched due to heating accompanying the drying of the ink, tension applied to the film, and the like before the film travels from one unit to the next unit. Even if the diameter of the printing roll is increased to correspond to the elongation of the film, it does not correspond to a perfect match, so that the phase of printing is aligned by the examination alignment device. However, to make printing rolls with slightly different diameters precisely, the plate making design also makes plate making by calculating the division angle so that the number of angle divisions does not change so that it becomes slightly longer in the circumferential direction of the roll, If the order of attaching the plate-making rolls to the printing machine is incorrect, there is a possibility that the film may not run smoothly on the line. At the printing site, the roll diameter is measured and the roll with the smaller diameter is installed so that the printing order is first. However, the order of printing depends on the color. For example, it is general that black-cyan-magenta-yellow-white are printed in that order, and spot colors such as gold and silver are generally in the order between yellow and white, but purple is between cyan and magenta. The order of colors to be printed is decided, such as the order of printing. However, for example, it makes a mistake to form a cyan plate on the roll with the smallest diameter and a black plate on the roll with the second smallest diameter. Becomes a big problem. Therefore, it is desired that all printing rolls have the same diameter.

In recent years, the precision of the gravure rotary printing machine has been greatly improved. For example, in a gravure rotary printing machine for 10-color printing, the diameters of a total of 9 printing rolls mounted on each unit except the 10th unit are changed. The diameter of the printing roll mounted on the tenth unit can be made larger than that of the other printing rolls by, for example, 20 to 30 μm to secure the tension of the web over substantially the entire length of the printing line. You can now print. Note that not all gravure rotary printing presses with greatly improved accuracy are in operation. Generally, the last row of printing is solid printing with a large white area or part coat (glue coating) that is a thick coating, and the diameter of the last row printing roll is made slightly larger. The plate making design also calculates the plate so that it becomes slightly longer in the circumferential direction of the roll, so the printing rolls in the last row correspond to the relationship between roll diameter and color, especially the relationship between roll diameter and plate content. Therefore, there is still a fear of causing a trouble in which the correspondence between the roll diameter and the color is wrong at the time of plate making. In addition, even if the accuracy of the gravure rotary printing press is greatly improved, if the printing rolls are all made to have the same diameter, it is not possible to cause tension in the film with the examination matching device, There is a problem that the film is no longer strained and printing cannot be performed properly.

Since the printing of the last row is a solid printing with a large white area or a part coat (paste coating) for thick coating, the dryer of the unit of the last row is equipped with a large-capacity dryer. It is designed to be strongly dried against glue and glue, so that if the film is not dried sufficiently, the wound film will not stick to the ink and the ink will not peel off when the film is rewound. It has been avoided. However, in the 8-color or 10-color gravure rotary printing machine, the large capacity of the dryer only in the last row had the following problems. In an 8-color rotogravure printing machine, for example, when performing 5-color or 6-color gravure printing in the first to fifth or sixth units, the drying capacity of the dryers in the fifth and sixth units is not large. Further, in a 10-color gravure rotary printing machine, when one printing is performed by the first to fifth units and another printing is performed by the tenth to sixth units, the dryer of the last row unit is used. Cannot be used for both prints. For the 1st printing of the 1st to 5th units, the drying of the 5th unit is the last row, and for the other printings of the 10th to 6th units, the drying of the 6th unit is the last row However, the drying capacity of the dryer of the 5th and 6th units is not large. When the printing of the fifth and sixth units is solid printing with a large white area and a large ink film thickness, or is a thick part coat, drying of the ink and part coat in the fifth and sixth units However, there was a problem that the printing speed had to be reduced in order to be performed sufficiently.

[0005]

SUMMARY OF THE INVENTION In the present invention, in a unit type multicolor printing machine, for example, a 4-color printing machine or a 10-color printing gravure rotary printing machine, all printing rolls mounted in each unit can have the same diameter. In addition, it is possible to secure the tension of the web over almost the entire length of the printing line and perform good printing.In addition, it is possible to reduce the drying load of the last row unit when printing, not the last row unit of the gravure rotary printing press. Further, it is an object of the present invention to provide a printing roll gravure printing method capable of avoiding a reduction in printing speed due to the necessary and sufficient drying of ink even if the drying capacity of the dryer of the unit in the last row is not large.

[0006]

According to a first aspect of the present invention, in a method of gravure printing by a unit-type multicolor gravure rotary printing machine, a roll base material is used for a printing roll of the gravure rotary printing machine in the last row. A traveling speed that is made of aluminum and is thermally expanded to a required diameter by heating the printing roll so that the printing roll has a required diameter, and the printing roll and the impression cylinder cooperate to pull and run the web that is the printing target. Is required to be higher than the traveling speed at which the printing rolls and impression cylinders of the gravure rotary printing machine other than the last row work together to pull and run the web, which is the material to be printed. It is intended to provide a gravure printing method characterized by ensuring tension and printing.

According to a second aspect of the present invention, the finisher roll of the rotogravure rotary printing press in the last row is made to flow the oil heated by the oil heater to the finisher roll, and the finisher roll heated to the required temperature is used as the print roll. The gravure printing method according to claim 1 is characterized in that the printing roll is brought into contact to heat and heat the printing roll.

According to the third aspect of the invention, the ink is heated by heating the ink tray of the gravure rotary printing machine in the last row, or a rod-shaped heater is provided in the ink tray to heat the ink, and The heat transfer / heating of the printing roll is performed via the finishing roll [Claim 1].
The gravure printing method described in 1. is provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows, for example, two-color printing or 10
The schematic front view of one unit concerning the unit type multicolor printing gravure rotary printing machine of color printing is shown. In FIG.
1 is an impression cylinder, 2 is a printing roll, 3 is a finisher roll,
4 is a guide arm for slidably restraining the shaft end of the finisher roll to bring the finisher roll 3 into contact with the printing roll by the biasing of a spring, 5 is a doctor, 6 is an ink tray, 7 is ink, and F is an object to be printed. Is. A rotary joint (not shown) is connected to the shaft portions at both ends of the finisher roll 3, and the rotary joint is further connected to a flexible tube (not shown). Oil heated by an oil heater whose temperature is controlled from one flexible tube is fed to flow inside the finisher roll 3 so that the finisher roll 3 becomes higher than a required temperature, for example, 10 ° C. higher than room temperature. The heating roll 3 is brought into contact with the printing roll 2 so that the ink 7 in the ink tray 5 is applied to the printing roll 2 via the finishing roll 3 and the finisher The roll 3 heats and heats the printing roll 2. It should be noted that the ink is heated by heating the ink tray, or a bar-shaped heater is provided in the ink tray to heat the ink, and then the printing roll is heat-transferred / heated via the finisher roll. It may be. or,
The present invention, each unit chucks the printing roll whose roll base material is aluminum, sends hot air into the inside of the printing roll through the chucking means to heat the printing roll to thermally expand it to a required diameter, The printing roll and the impression cylinder work together to pull and run the web that is the material to be printed. The printing speed and the impression cylinder of the gravure rotary printing machine other than the last row work together to pull the web that is the material to be printed. The required speed is higher than the running speed, and
It is also possible to secure the tension of the web over substantially the entire length of the printing line before printing.

In the unit type gravure rotary printing machine applied to carry out the gravure printing method of the present invention, it is assumed that each unit has the structure shown in FIG. The printing roll can be heat-transferred / heated regardless of which unit is the last row unit at the time of printing, not the last row unit of the printing press.

The gravure printing method of the present invention uses a printing roll whose roll base material is aluminum for the printing rolls of the last row unit during printing. The reason is that the coefficient of thermal expansion 23.5 × 10 ^{−6 of} aluminum is about twice as large as the coefficient of thermal expansion 11.5 × 10 ⁻⁶ of steel.
This is because it can be thermally expanded by 0 μm. Therefore,
This is because the roll diameter of the last printing roll during printing can be expanded by 20 to 30 μm more than that of the other printing rolls, so that it can be made the same diameter as the other printing rolls during plate making. The printing roll of the unit that is the last row at the time of printing refers to the printing roll of the fifth unit when, for example, the gravure printing of the five-color printing is performed by the first to fifth units in a gravure rotary printing machine of the eight-color printing, for example. . Further, in a 10-color printing gravure rotary printing machine, when one printing is performed by the first to fifth units and the other printing is performed by the tenth to sixth units, the printing roll of the fifth unit is used. Refers to the printing roll of the sixth unit. In the gravure printing method of the present invention, the printing roll in the last row at the time of printing is heated to a required temperature according to the roll diameter and thermally expanded to have the required diameter, and the printing roll and the impression cylinder work together. The traveling speed to pull and run the web to be printed is required to be higher than the running speed to pull and run the web to be printed by the printing roll and the impression cylinder of the gravure rotary printing machine other than the last row working together. Therefore, the web is printed while ensuring the tension of the web over substantially the entire length of the printing line. Regarding how many times the temperature is raised for the printing roll that is the last row during printing, the expansion coefficient of aluminum, its roll diameter, and
Based on three factors, how long the circumference should be longer than other printing rolls in order to pull the film, and how much should the diameter be thermally expanded when converted to the change in diameter. The required calculation is performed to calculate the temperature at which the print roll is heated. Then, the temperature and amount of the oil that is made to flow through the finisher roll is controlled, or the temperature at which the ink tray is warmed is determined.

According to the invention of the present application, the structure for transferring heat to the printing roll is provided so that the unit of the last row at the time of printing may be any unit instead of the unit of the last row of the unit type gravure rotary printing press. It is preferable to be provided in all units other than the first unit.

[0013]

As described above, the gravure printing method according to the first aspect of the present invention has the following effects. (1) The multi-color gravure rotary printing press is not the last row unit but the printing roll of the last row unit is heated by, for example, about 10 ° C. to expand the diameter when printing, so all the printing to be mounted on each unit It is possible to make the rolls with the same diameter, and even if all the printing rolls have the same diameter, the printing rolls in the last row of units are heated to expand the diameter when printing. Good printing can be performed because the film can be effectively towed and run, and tension can be applied to the film over the entire line. (2) Since the diameter of all printing rolls can be made the same, the trouble of making printing rolls with slightly different diameters precisely is eliminated, and the platemaking design also becomes slightly longer in the circumferential direction of the rolls. Correspondingly, it is not necessary to calculate the division angle to make the plate, and the problem that the roll diameter does not correspond to the plate is solved. (3) The multi-color gravure rotary printing press is not the last row unit but the printing roll of the last row unit is heated by, for example, about 10 ° C. to expand the diameter when printing, so any improvement or modification to the printing machine is not allowed. It suffices to add a means for heating the finisher roll or a means for heating the ink tray for all units. As for the printing roll, the printing roll whose roll base material is aluminum is at least the unit in the last row at the time of printing. It is enough to use. (4) Since the printing roll is overheated, the ink is also overheated and the drying load is small. Therefore, for example, in a 8-color gravure rotary printing machine, for example, when performing 5-color or 6-color gravure printing in the first to fifth or sixth units, or in a 10-color gravure rotary printing machine, When one printing is performed by the fifth unit and the other printing is performed by the tenth to sixth units, the fifth and sixth units are printed by solid printing with a large white area and a large ink film thickness. There is
Alternatively, in the case of a thick-coated part coat, the fifth and sixth units are in the last row at the time of printing, but since the drying capacity of the dryer is not large, it is necessary and sufficient to dry the ink and part coat. Eliminates the conventional problem that the printing speed must be reduced.

[Brief description of drawings]

FIG. 1 is a schematic front view of one unit according to an embodiment of the present invention, for example, a unit type multi-color gravure rotary printing machine for two-color printing or ten-color printing.

[Explanation of symbols]

1 ... impression cylinder, 2 ... printing roll, 3 ... finisher roll, 4 ... guide arm, 5 ... doctor, 6 ... ink tray, 7 ... ink, F ... ..Printed materials,

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeru Suzuki             1201-11 Takada, Kashiwa City, Chiba Shin Co., Ltd.             Inside the laboratory F-term (reference) 2C250 DA04 DB11 DC05

Claims (3)

[Claims] 1. A gravure printing method using a unit-type multi-color rotary gravure printing machine, wherein the roll base material of the printing roll of the gravure rotary printing machine in the last row is made of aluminum, and the required temperature of the printing roll is reached. The printing rolls of the gravure rotary printing machine other than the last row are heated to be thermally expanded to a required diameter, and the printing roll and the impression cylinder cooperate to pull and run the web that is the printing target. The gravure is characterized in that the printing speed is made faster than the traveling speed by which the printing material web and the impression cylinder work together to pull and run the printing material web, thus ensuring the tension of the web over substantially the entire length of the printing line. Printing method. 2. A furnisher roll of a rotogravure rotary printing press in the last row is made to flow oil heated by an oil heater to bring the furnisher roll heated to a required temperature into contact with the print roll to form the roll. The gravure printing method according to claim 1, wherein heat transfer / heating is performed. 3. The ink is heated by heating the ink tray of the gravure rotary printing machine in the last row, or a bar-shaped heater is provided in the ink tray to heat the ink, and further, the ink is heated via a finisher roll. The gravure printing method according to claim 1, wherein the printing roll is heat-transferred / heated.