JP3488866B2 - Metal plate printing method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for printing a metal plate for printing a decorative pattern or the like on the surface of the metal plate as represented by a coated steel plate.

[0002]

2. Description of the Related Art A gravure offset method is used for printing metal sheets of this kind, and ink made of resin for metal sheets is transferred from a metal plate roll to an offset roll (rubber roll) whose surface is covered with rubber. Transferred, and then retransferred from the offset roll to the metal plate. In this case, the printing pressure suitable for ink transfer is a very light pressure called kiss touch. Conventionally, the transfer to the offset roll and the retransfer to the metal plate have been visually confirmed. In many gravure offset printings, a predetermined printing pressure (nip pressure) is set visually or with a pressure gauge before starting printing.
This is because when the nip pressure changes, the ink transfer to the metal plate is affected. Regarding the ink transfer property, if the nip pressure is weak, the ink transfer is poor, and uneven printing is likely to occur.
If the printing pressure is too high, the halftone dots are crushed, and the tone of color strength and shade, that is, the color tone becomes unclear, causing problems in print quality.

[0003]

However, in the above-described printing apparatus for a metal plate which uses an offset roll whose surface is covered with rubber, since the printing ink contains a solvent, the offset roll is used in the process of printing. The coated rubber on the surface of swells with a solvent, the outer diameter of the offset roll fluctuates, and the set nip pressure changes. Conventionally, the nip pressure, which is increased by the swelling of the offset roll due to the solvent, has not been controlled. Therefore, the ink transfer property gradually changes with a change in the nip pressure, which adversely affects the color tone and print quality.

An object of the present invention is to improve the printing quality of a metal plate and to maintain a stable color tone by automatically controlling the change of the nip pressure due to the swelling of an offset roll whose surface is covered with rubber. A method and an apparatus therefor are provided.

[0005]

The method for printing a metal plate of the present invention comprises a plate roll made of metal, and the ink on the surface of the plate roll is transferred and printed on the plate roll in contact with the plate roll.
A method for printing a metal plate comprising an offset roll whose surface is covered with rubber and a backup roll which is pressed from the back face of the metal plate to the offset roll side, and detects the nip pressure between the plate roll and the offset roll, and this detection is performed. The plate roll or offset roll is moved away based on the signal to control the nip pressure to the set nip pressure, and at the same time, the amount of movement of the moved plate roll or offset roll is detected, and the offset is detected based on this detection signal. It is characterized in that the nip pressure between the roll and the backup roll is controlled to be the set nip pressure.

Further, according to the method for printing a metal plate of the present invention, a metal plate roll and a backup roll are arranged so as to be able to move toward and away from an offset roll which is installed at a fixed position and whose surface is covered with rubber. In the printing method of the metal plate for transferring the ink on the surface of the offset roll to the surface of the metal plate passed between the offset roll and the backup roll, the nip pressure between the plate roll and the offset roll is detected on the plate roll side, Based on this detection signal, the plate roll is moved with respect to the offset roll to control the nip pressure with the offset roll to the set nip pressure,
At the same time, the moving amount of the plate roll is detected, and the backup roll is moved with respect to the offset roll based on this detection signal to control the nip pressure with the offset roll to be the set nip pressure. It is a thing.

According to the printing method of the metal plate, the nip pressure between the plate roll and the offset roll is detected, and the plate roll or the offset roll is moved so as to reach the set nip pressure by the detection signal. Therefore,
Since the set nip pressure can be maintained even when the offset roll swells with the solvent in the printing ink, it is possible to prevent changes in ink transferability, color tone, and print quality.

When the offset roll swells, the nip pressure with the backup roll also changes. In this case, the nip pressure may be detected and controlled by, for example, a load cell installed on the backup roll. But,
The backup roll pushes up the metal plate with line tension to press it against the offset roll. The line tension applied to the metal plate varies depending on the plate thickness and the plate width of the metal plate, but is generally 2,000 to 10,000 Kgf. With such a large line tension, the load cell installed on the backup roll will necessarily have a large specification. In addition, the change in the line tension due to the fluctuation of the oven catenary becomes large. However, the pressure range (20 to 100 Kgf) desired to be controlled by printing is small and difficult to detect, and even if it can be detected, it cannot be distinguished from the line tension fluctuation. Therefore, the nip pressure cannot be controlled. Therefore, in the present invention, as to the nip pressure control of the backup roll, as in the above configuration, the amount of movement of the plate roll moving motor is detected, and the backup roll is moved with respect to the offset roll based on this detection signal. Control nip pressure. As a result, the nip pressure between the offset roll and the backup roll can be maintained at the set nip pressure, so that changes in ink transferability, color tone, and print quality can be prevented.

The metal plate printing apparatus of the present invention comprises a plate roll made of metal, and an ink on the surface of the plate roll is transferred and printed on the surface of the plate by contacting the plate roll. In a printing device for a metal plate including a roll and a backup roll that presses from the back surface of the metal plate to the offset roll side, a nip pressure detection sensor that detects the nip pressure between the plate roll and the offset roll is provided on the plate roll side. And a motor for moving the plate roll with respect to the offset roll so that the nip pressure between the plate roll and the offset roll becomes the set nip pressure by inputting the detection signal. On the side, the result of calculating the amount of movement by the computer for moving the plate roll by the computer is fed back,
It is characterized in that a moving motor for moving the backup roll with respect to the offset roll is installed so that the nip pressure between the offset roll and the backup roll becomes a set nip pressure.

According to the above-mentioned metal plate printing apparatus, even if the offset roll swells with the solvent in the printing ink, the nip pressure between the plate roll and the offset roll can be maintained at the set nip pressure, and the offset roll and the backup roll can be maintained. The nip pressure between them can also be maintained at the set nip pressure, and changes in ink transferability, color tone, and print quality can be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a continuous printing line of a metal plate to which the present invention is applied. In this printing line, a metal plate W such as a steel plate web is unwound from the uncoiler 1 and immersed in chromic acid or phosphoric acid solution for surface treatment, and a first coating for coating the surface of the metal plate W. After the metal plate W is printed by sequentially sending the portion 4, the second coating portion 5, and the printing portion 6, the metal plate W is wound around the recoiler 8 via the tension leveler 7 in a roll shape. There is.

Four bridle rolls 9, 10, 11, 1 for feeding the metal plate W are respectively provided at the front, middle, and rear stages of the first and second coating units 4, 5, and at the rear stage of the printing unit 6.
2 are arranged, and the bridle rolls 9, 10, 1 are arranged on the basis of the peripheral speed of the bridle roll 12 at the final stage.
The tension state of the metal plate W passing through the first, second coating sections 4, 5 and the printing section 6 is controlled by changing the peripheral speed of No. 1 to be large or small.

In FIG. 5, in the first coating section 4, the roll coater 13 is used to form the front surface (upper surface) and the back surface (lower surface) of the metal plate W.
After the coating agent is applied to each of the primer layers 15a and 16
a is formed. In the second coating section 5, coating is performed by the roll coater 17 as in the case of the first coating section 4, and the colored base layer 15b (see FIG. 6) is applied to the surface of the primer layer 15a.
After forming, the coating material is forcibly dried in the oven 18. Therefore, the base layer 15 on the front surface side is composed of two layers of the primer layer 15a and the colored base layer 15b, or a single layer of the colored base layer 15b. In the second coating section 5, the coating layer 16b is applied by the roll coater 17 to the surface of the primer layer 16a on the back surface that has already been coated, and the underlayer 16 on the back surface is divided into inner and outer two layers 16a and 16b. Sometimes formed. The coating agent used in the first and second coating parts 4 and 5 is, for example, a polyester resin coating material, an epoxy resin coating material, an acrylic resin coating material, a fluorine resin coating material, or the like. If necessary, a rust preventive pigment is added to the coating agent to be formed.

The printing unit 6 is provided with a printing device capable of carrying out the printing method of the present invention. This printing device is shown in FIG.
As shown in, the roll printing machines 20 and 21 are provided adjacent to each other along the transport path of the metal plate W, and the roll printing machines 20 and 21 are provided on the underlayer 15 on the front surface side of the metal plate W. For example, the print layer 22 such as a wood grain pattern is printed in multiple colors. The ink for forming the printing layer 22 is a normal resin for metal plate, for example, polyester resin, alkyd resin, fluorine resin or the like ink is used. After printing, a clear coating is applied to the entire surface of the underlayer 15 including the printing layer 22 by a curtain coater 23 or a roll coater as shown in FIG. 6 to form a protective layer.
2 and the protective layer are forced to dry simultaneously in the oven 25. As shown in FIG. 7, an auxiliary dryer 26 that blows out hot air is installed at the rear stage of each of the printing machines 20 and 21. Examples of the clear coating material for forming the protective layer include polyester resin coating material, epoxy resin coating material, acrylic resin coating material, fluorine resin coating material and the like.

In FIG. 3, each roll printing machine 20, 21
Is a gravure offset printing machine, and is a metal plate roll 28 composed of a gravure roll, and this plate roll 28.
The offset roll 29 is configured to transfer and print the ink on the surface of the plate roll 28 onto the surface of the metal plate W, and the backup roll 30 that presses the back surface of the metal plate W toward the offset roll 29. Offset roll 2
The surface of 9 is covered with rubber such as urethane rubber and fluororubber (for example, rubber hardness 45 degrees). Reference numeral 31 is an inking head that directly charges the surface of the plate roll 28 with the printing ink fed under pressure. The plate roll 28 and the offset roll 29 are the servo motor 3 respectively.
2 and 33 are used as drive sources, and are rotationally driven through a joint such as an Oldham shaft joint. The backup roll 30 is rotationally driven by a servo motor 34 via a joint.

The long metal plate W is formed by each bridle roll 9-.
Since the tension is controlled by 12 (see FIG. 1), the feeding speed of the metal plate W passing through the roll printing machines 20 and 21 is not constant and varies every time the tension control is performed. In order to prevent the expansion and contraction of the printed pattern due to such a change in the feed speed, as shown in FIG.
A non-contact type plate speed meter 36 for detecting the feeding pitch of the metal plate W is arranged near the printing position of, and on the upstream side of the printing position in the metal plate feeding direction. The feed pitch signal detected by the plate speed meter 36 and the rotation pulse signal fed back from the servo motor 32 are compared by a computer of the control device 37 for speed control, whereby the rotation pitch of the plate roll 28 is metal. The drive rotation speed of the servo motors 32 and 33 is controlled to increase or decrease so as to match the feed speed of the plate W. With this, the rotational pitches of the plate rolls 28 and 28 and the offset rolls 29 and 29 of the front and rear roll printing machines 20 and 21 are matched with the feeding speed of the metal plate W.

In the above printing apparatus, when an offset roll (rubber roll) 29 having a surface coated with rubber is used,
During the printing process, the coating rubber on the surface of the offset roll 29 swells with the solvent in the resin ink. Due to this swelling, the outer diameter of the offset roll 29 changes, and the set nip pressure changes. When the nip pressure changes, the transferability of ink changes, which causes a change in print color tone and print unevenness.

Therefore, the plate roll 28 and the offset roll 2 are increased by the swelling of the offset roll 29 by the solvent.
The nip pressure between 9 and the nip pressure between the offset roll 29 and the backup roll 30 are automatically controlled by the control device 50 for controlling the nip pressure. To that end, FIG.
As shown in FIG. 4, the offset roll 29 is fixed at a fixed position, and the plate roll 28 and the backup roll 30 approach and depart from the offset roll 29 (indicated by arrows A and B in FIG. 4 indicating contact and separation directions). It is installed so that it can be moved to. The plate roll 28 is provided with a nip pressure detecting sensor 51 such as a load cell.
The nip pressure with the offset roll 29 is detected by. The coating rubber on the surface of the offset roll 29 is swollen by the solvent in the ink (the swollen state is shown by the broken line E in FIG. 4), and the nip pressure detected by the nip pressure detection sensor 51 is lower than the set nip pressure. In the case where the plate roll 28 has increased, the plate roll 28 is moved backward together with its drive shaft by a moving motor 52 such as a servomotor installed on the shaft mount of the plate roll 28 (the moving position indicated by a chain double-dashed line F in FIG. 4). Control) so that the set nip pressure is reached.

On the other hand, for controlling the nip pressure of the backup roll 30, the motor 5 for moving the plate roll 28 is used.
The amount of movement by 2 (the number of rotations of the movement motor 52) is calculated by the computer of the control device 50, and the result is fed back to the movement motor 53 installed on the shaft mount of the backup roll 30 and backed up by the movement motor 53. The roll 30 is moved backward from the offset roll 29 (the moving position is indicated by a chain double-dashed line G in FIG. 4), and the backup roll 30 and the offset roll 2
The nip pressure between 9 is also controlled so as to reach the set nip pressure at the same time.

In the above embodiment, the offset roll 29 is fixed at a fixed position, and the plate roll 28 and the backup roll 3 are
0 is installed so that it can move toward and away from the offset roll 29, but instead of this, the backup roll 30 is fixed in a fixed position, and the offset roll 29 is moved to control the nip pressure with the backup roll 30. , The plate roll 28 is fixed at a fixed position, the offset roll 29 is moved to control the nip pressure with the plate roll 28, and the backup roll 30 is moved with the detection signal of this movement amount to nip with the offset roll 29. It is also possible to control the pressure or to fix the backup roll 30 in a fixed position and move the offset roll 29 to control the nip pressure with the plate roll 28 and the nip pressure with the backup roll 30.

By controlling the nip pressure between the plate roll 28 and the offset roll 29, and the nip pressure between the offset roll 29 and the backup roll 30 and the position control in this way, the offset roll 29 is swollen by the solvent in the printing ink. Even if it does, stable printing quality can be maintained.

In the above continuous printing line,
A metal plate W such as a steel plate, a plated steel plate, a stainless steel plate, or an aluminum plate can be used as a base material, and its surface can be subjected to predetermined coating and printing. The plate roll 28, the offset roll 29, and the backup roll 30 are preferably driven by dedicated motors 32, 33, 34, respectively,
It is also possible to drive the offset roll 29 and the backup roll 30 synchronously via a gear mechanism by using one motor 32 that drives the plate roll 28 as a drive source.

The plate roll 28 of the printing apparatus of the present invention is not limited to a gravure roll (intaglio roll), but a letterpress roll may be used. Further, the roll printing machine can be applied when one machine or two or more machines are arranged adjacent to each other. The plate speed meter 36 is preferably a non-contact type, but may be of a type that contacts the metal plate W, for example, a contact type that detects the plate speed with a touch roller. When printing a pattern or the like on the metal plate W cut into a certain length, the plate speed meter 36 and the control device 37 are unnecessary. As the phase detection sensors 40 and 41, other than the optical sensor, a magnetic sensor, a proximity switch, or another sensor such as a rotation speed sensor can be used.

[0024]

According to the present invention, the nip pressure between the plate roll and the offset roll and the nip pressure between the offset roll and the backup roll are constantly controlled to the set nip pressure by automatically controlling the change in the nip pressure due to the swelling of the offset roll. Since it can be held, there is an advantage that the printing quality of the metal plate can be improved and a stable color tone can be maintained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a continuous printing line for metal plates.

FIG. 2 is a schematic diagram showing a basic configuration of a printing unit of a continuous printing line for a metal plate.

FIG. 3 is a schematic diagram showing a part of the basic configuration of the printing unit shown in FIG.

FIG. 4 is a schematic configuration diagram of a lip pressure control device of the printing unit in FIG.

FIG. 5 is a schematic configuration diagram of a coating section of a continuous printing line for metal plates.

FIG. 6 is a schematic configuration diagram of a printing unit of a continuous printing line for a metal plate.

FIG. 7 is a schematic diagram showing an overall configuration of a printing unit of a continuous printing line for a metal plate.

[Explanation of symbols]

28th edition roll 29 Offset roll 30 backup rolls 50 Control device for nip pressure control 51 Nip pressure detection sensor Motor for moving plate 52 53 Motor for moving backup roll

Front Page Continuation (72) Inventor Takashi Jinno 4-1-1 Minamihonmachi, Chuo-ku, Osaka-shi, Osaka Inside Yodogawa Steel Works Co., Ltd. (56) Reference JP 5-278194 (JP, A) JP 2000- 246881 (JP, A) JP 4-327941 (JP, A) JP 64-40630 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41F 13/24 B41F 33 / 08 B41F 33/14

Claims (3)

(57) [Claims] 1. A metal plate roll, an offset roll whose surface is covered with rubber, which is in contact with the plate roll to transfer and print the ink on the surface of the plate roll onto the surface of the metal plate, and from the back surface of the metal plate. A method of printing a metal plate consisting of a backup roll pressed against the offset roll side, detecting the nip pressure between the plate roll and the offset roll, and moving the plate roll or the offset roll away from each other based on this detection signal to move the nip pressure. Is controlled to reach the set nip pressure, and at the same time, the moving amount of the moved plate roll or offset roll is detected, and the nip pressure between the offset roll and the backup roll is set to the set nip pressure based on this detection signal. A method for printing a metal plate, which is characterized in that 2. A metal plate roll and a backup roll are arranged so as to be able to move toward and away from an offset roll which is installed at a fixed position and whose surface is covered with rubber, and is passed between the offset roll and the backup roll. In the printing method of the metal plate that transfers and prints the ink of the surface of the offset roll on the surface of the metal plate, the nip pressure between the plate roll and the offset roll is detected on the plate roll side, and the plate roll is offset roll based on this detection signal. The nip pressure with the offset roll is controlled to reach the set nip pressure, and at the same time, the amount of movement of the plate roll is detected, and the backup roll is moved with respect to the offset roll based on this detection signal. And control the nip pressure with the offset roll to the set nip pressure. The method of printing. 3. A metal plate roll, an offset roll whose surface is covered with rubber, which is in contact with the plate roll to print the ink on the surface of the plate roll on the surface of the metal plate, and a back surface of the metal plate. In a printing device for metal plates consisting of a backup roll that presses from the offset roll to the offset roll side, a nip pressure detection sensor that detects the nip pressure between the plate roll and the offset roll and the detection signal are input to the plate roll side. A motor for moving the plate roll with respect to the offset roll so that the nip pressure between the plate roll and the offset roll becomes the set nip pressure. The result of calculating the amount of movement by the moving motor on the computer is fed back, and the difference between the offset roll and the backup roll is reported. Printing apparatus of the metal plates, characterized in that the flop pressure are backup rolls so that the set nip pressure established a movement motor for moving relative offset roll.