JPH07102673B2 - Rotary screen 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 printing method and apparatus for performing continuous multicolor printing on a long base material such as various papers, films or metal foils using a rotary screen.

[0002]

2. Description of the Related Art Unlike offset printing or rotogravure printing, screen printing has a thick printing ink layer and is excellent in volume feeling, density, and shielding properties, but it has a high intermediate drying ability. On the other hand, there is a tendency to increase the number of printing colors, which is required.

For screen printing, a flat screen is used, and a flat screen printing method in which a substrate is intermittently conveyed to perform printing, and a rotary screen are used.
There is a rotary screen printing method that performs printing while continuously feeding the substrate, but when the number of printing colors increases, the longitudinal dimension of the device increases significantly, and in a so-called wet-on-dry state in which printing ink does not bleed If you try to apply it, you have to intervene in a special area for intermediate drying,
There is a problem that the device becomes extra long and the device cost and the printing cost also increase.

In particular, in recent years, the taste has become individual and printing of small lots and a wide variety of products is required. Therefore, the advent of a printing machine with a small space and a low cost that meets these requirements is desired.

Therefore, the present invention aims to: (1) Multi-color printing is possible even with a small number of printing units by the multi-pass method, which reduces machine costs, saves space, and improves workability. (2) The intermediate drying unit linked to the printing unit
The multi-pass system can be effectively used, and the direct heating system to the heater roller enhances the drying ability to improve the printing quality and save energy.

[0006]

According to the present invention, a printing unit including a rotary screen and a counter roller is provided between a substrate rewinding device capable of forward and reverse rotation and a printed matter winding device capable of forward and reverse rotation, and At least one pair of intermediate drying units consisting of a heater roller and a hot air blowing section around the heater roller is arranged, and the rotary screen, the counter roller, and the heater roller are driven at a synchronized speed,
A base material is supplied to this with a constant tension, the ink layer applied on the base material is dried by a heater roller and hot air blowing, and the dried printed matter is wound up with a constant tension to form a base material unwinding device. The printed matter take-up device and the drive system of the printing unit and the drying unit are reversed, and the substrate is allowed to pass through the same path in the opposite direction to rewind the printed matter, and if necessary, the substrate unwinding device. There is provided a rotary screen printing method characterized in that the printed material winding device and the drive system of the printing unit and the drying unit are rotated in the forward direction to perform multi-pass printing.

According to the present invention, further, there is provided a base material unwinding device capable of forward and reverse rotation, a tension sensor and a tension applying device provided on the unwinding side of the unwinding device, a rotary screen and a counter roller. At least one printing unit that applies printing ink to the material, at least one intermediate drying unit that is provided subsequent to each printing unit and that includes a heater roller that contacts the back surface of the printing substrate and a hot air blowing section around the heater roller. And at least one cooling unit that is provided subsequent to each intermediate drying unit and that includes at least one cooling roller and a pinch roller that presses the base material against the cooling roller, a rotary screen, a counter roller, a heater roller, and cooling. A drive system that drives the rollers in the forward and reverse directions at a synchronized speed, and Consists of a tension sensor and a tension applying device provided on the feeding side of the printing unit, and a printed material winding device capable of reversing forward and backward, and the base material unwinding device, the printed material winding device, and the drive system of the printing unit and drying unit are reversed. In addition, a rotary screen printing device capable of rewinding a printed matter, rotating the substrate unwinding device, the printed matter winding device, and the drive system of the printing unit and the drying unit in the forward direction to perform printing and multi-pass printing is provided. Provided.

In the present invention, the intermediate drying unit is arranged above the printing unit, the heater roller has a larger diameter than the rotary screen and the counter roller, and the back surface of the printing substrate has a length of more than half the circumference of the heater roller. It is preferable that the intermediate drying is performed efficiently and the driving is performed accurately.

[0009]

According to the present invention, a printing unit including a rotary screen and a counter roller, and an intermediate drying unit including a heater roller and a hot air blowing section around the heater are provided between the substrate unwinding device and the printed matter winding device, or at least further. At least one pair of cooling units consisting of one cooling roller is arranged to drive the rotary screen and the counter roller, the heater roller, or the cooling roller at a synchronized speed. The first feature is that all of the feeding device and the winding device can be rotated in the forward and reverse directions. For this reason, the base material is rewound and passed twice, or three times.
Multi-color printing is possible by multi-pass such as through,
This method and apparatus are suitable for multi-product, small lot printing.

In both the printing process and the rewinding process by the multi-pass, the substrate passes through the same system path in the forward and reverse directions as it is. Therefore, the intermediate drying unit can be effectively used and the drying capacity can be enhanced.

Since the intermediate drying unit is a combination of direct heating by a heater roller and blowing hot air, the drying efficiency is high, and the size and energy saving can be reduced.

The back side of the printed surface of the substrate contacts the heater roller,
Since it is directly heated, the solvent component in the printing ink can be easily diffused and dried quickly. Therefore, it is possible to prevent blocking of the printed surface (when the drying is insufficient, the ink layer is peeled off, color transfer and stain are generated on the guide roller or the back surface of the substrate).

The base material is mainly conveyed by the heater roller,
Since it is driven, the contact length and frictional force with the base material are large, the base material can be driven accurately and stably, and the registration (form) accuracy is high even in multi-pass printing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall side view of an embodiment of the rotary screen printing machine of the present invention. As shown in FIG. 1, the rotary screen printing machine includes an unwinding device 10, a printing unit 20,
It is composed of a driving device 30, an intermediate drying unit 40, a cooling unit 29, and a winding device 50, each of which is installed on the base frame 1.

As described above, the apparatus of the present invention is capable of rewinding and multi-pass printing. Therefore, the substrate 2 is fed in the direction indicated by the solid line in the drawing in the printing process, that is, from the right side to the left side in the figure, and in the rewinding process in the direction indicated by the dotted line arrow in the direction opposite to the printing process. Sent.

The selection of the printing process and the rewinding process can be easily performed by switching the "printing mode" and the "rewinding mode" using a mode changeover switch (not shown) provided on the machine operation panel surface.

In the unwinding device 10, the printing substrate 2 wound on the core 3 in a roll shape is rotatably supported by the unwinding frame 11, and the unwinding motor 12 drives the roller chain 13 and the like. It is driven via the powder clutch 14.

The powder clutch 14 follows the value of the unwinding tension optimally set on the machine operation panel, and
It acts as a brake in the unwinding direction of. The actual unwinding tension is detected by the tension sensor 15, and based on comparison with the set tension, the powder clutch 1
It controls the voltage supplied to 4 and maintains the set tension at all times. It is of course possible to use a tension adjusting mechanism such as another electromagnetic clutch instead of the powder clutch 14.

An edge sensor 16 is provided between the unwinding device 10 and the tension sensor 15, and the output device causes the entire unwinding device 10 to move in the width direction of the base material 2 to cause the base material 2 to move.
The entry position of the paper into the printing unit 20 is constantly regulated.

For the first printing, the base material 2 sent in the direction of the solid line arrow in the figure is guided by the guide rollers 4 at various places to reach the rotary screen 21 portion, and the squeegee between the counter roller 23 and the counter roller 23. The first color is printed by 22. The rotary screen 21 and the counter roller 23 are rotationally driven by a driving device 30 described later in synchronization with the substrate speed.

The base material 2 on which the first color is printed is dried by the intermediate drying unit 40 on the upper side. A heater roller 41 having a diameter considerably larger than that of the rotary screen 21 and the counter roller 23 is rotatably supported at the center of the intermediate drying unit 40, and a timing pulley 42 fixed to the heater roller 41 drives the heater roller 41 in synchronization with the substrate speed.

By a known method, the heater roller 41 is supplied with steam from the hole 41A of the shaft core and is uniformly heated from the inside. The back side of the printed surface of the printed base material 2 is wrapped around the outer peripheral surface of the heater roller 41, and the solvent component of the front surface ink layer is diffused without any trouble by direct heating from the back surface to accelerate drying.

Further, the base material 2 has a long contact length with the heater roller 41, and a large area contact and a base material tension do not cause a slip, so that the base material 2 is accurately and stably driven. Heater roller 4
The outer diameter D of No. 1 is φ800 mm in the embodiment,
It can be set arbitrarily depending on the type of substrate and printing conditions.

In the intermediate drying unit 40, hot air is blown toward the printed surface of the substrate to accelerate the drying.
A heat source device 43 is provided for blowing hot air, and a blower fan 44 is arranged on the secondary side. Thereby, the heat source device 4
The primary side air of No. 3 is heat-exchanged and heated, and becomes hot air and is sent to the duct 45.

The hot air sent to the duct 45 is blown onto the surface of the base material from a large number of nozzles 46. In the embodiment, steam is used as the heat source, and the hot air temperature is 70 ° C. to 1 ° C.
The temperature is 30 ° C., and the velocity of air blown from the nozzle is 15 m / sec to 20 m / sec. By using thermo oil or the like as a heat source depending on printing conditions, it is possible to generate hot air at a higher temperature, and the wind speed of the nozzle part can be set arbitrarily and optimally.

Although not shown, the intermediate drying unit 40
Is equipped with an exhaust device, which discharges polluted air containing solvent vaporized gas and the like in the drying chamber to the outside and constantly supplies fresh heated air.

The substrate 2 on which the ink has dried or gelled after passing through the intermediate drying unit 40 advances in the direction of the solid arrow through the guide roller 4 and is cooled by the two cooling rollers 24 of the cooling unit 29. After that, it is sent to the next printing unit. As the cooling roller 24, a known cooling water flow-through type is used.

A pinch roller 28 is rotatably provided above the cooling roller 24, and an air cylinder 28A is provided.
The base material 2 is brought into pressure contact with the cooling roller 24 by the pressing force. As a result, slippage between the base material 2 and the cooling roller 24 is prevented, and fluctuations in the base material tension are suppressed, so-called tension cut effect is exhibited, and registration accuracy is improved. When the heat capacity of the base material 2 is small, it is natural that the cooling by the cooling unit 29 can be omitted.

The rotary screen 21, the counter roller 23, the cooling roller 24, and the heater roller 41 in the intermediate drying unit 40 of each of the first and second printing units 20 are synchronously driven by a driving device 30 capable of forward and reverse rotation. Then, the substrate 2 is sent at the set speed.

The drive motor 31 has a timing belt 32.
Alternatively, the line shaft 33 is rotationally driven by another driving means. The life shaft 33 connects the first and second printing units, and the worm reducer 3 provided in each of them.
In step 4, the two printing units are synchronously driven.

The gear 35 fixed to the output shaft of the worm speed reducer 34 meshes with the gear 24A for the cooling roller 24, drives the gear 24A, and drives the timing pulley 25,
The timing belt 26 applies synchronous drive to the rotary screen 21, the counter roller 23, and the heater roller 41 in the intermediate drying unit 40 via a rotary screen drive device 27 (details omitted).

The substrate 2 which has been printed and dried in two colors in one pass is wound into a roll on the winding device 50 at the rear portion. The winding device 50 has the same structure as that of the unwinding device 10, and the core 3 that winds the base material 2 is driven by the winding motor 52 via the driving means such as the roller chain 53 and the powder clutch 54. It Further, as in the unwinding device 10, the winding tension is controlled by the tension sensor 55 and the powder clutch 54, and the edge sensor 56 regulates the widthwise position of the base material 2.

The embodiment of FIG. 1 shows the case of 2-unit, 2-color printing. In the case of printing with two or less colors, the work is completed in the above steps, but when printing with two or more colors, the rotary screen 21 and the squeegee 22 are removed first, and the base material 2 is taken up from the unwinding device 10. The machine is stopped and then the rewinding operation is performed with the path up to 50 left.

In the rewinding operation, the drive device 30 rotates in the reverse direction only by switching the mode changeover switch of the machine operation panel to the "rewinding mode", and the substrate 2 moves backward in the direction of the dotted line arrow in the figure. In this case, it is not necessary to remove the base material 2 wound up by the winding device 50, and rewinding can be performed without changing the intermediate system path. Cooling unit 2 when rewinding
The cooling by 9 does not allow the cooling water to flow through and can be prevented.

At the time of rewinding, the winding device 50 functions as a winding device and the winding device 10 functions as a winding device. In this case, the values of the unwinding tension and the winding tension are often different, but the tension can be automatically switched by setting the two kinds of tension values of the unwinding and the winding.

As soon as the rewinding work is completed, the next rotary screen and squeegee are set, and the changeover switch is changed to the "printing mode". As described above, the base material 2 advances in the direction of the solid arrow, and the third and fourth colors are moved. After being printed and dried, it is wound up by the winding device 50. By repeating this, printing for the required number of colors is completed.

When printing three or more colors (second pass), the rotary screen 21 is moved by a phase adjusting device (not shown).
Can adjust the phase at an arbitrary position within a 360-degree range, and can quickly adjust the registration for the pattern at the time of printing the first color or two colors of the first pass. It is also possible to use a commercially available automatic registration device.

As described above, the base material 2 passes through the intermediate drying unit 40 in both the printing process and the rewinding process to be sufficiently dried. Further, after the printing process of the final pass, the final drying is performed by rewinding if necessary and passing through the intermediate drying unit 40 again.

FIG. 1 and the above detailed description refer to two units,
In the case of 1-pass 2-color printing, since it is the multi-pass method as described above, it is of course possible to use one unit or three or more units depending on the maximum required number of colors, work efficiency and the like.

[0040]

According to the present invention, the printing unit and the drying unit are arranged as described above, and the drive system and the front and rear unwinding devices and winding devices are all capable of rotating in the forward and reverse directions. Unwinding the material and passing it twice, or 3
Multi-color printing is possible by multi-pass such as through,
The advantage is that it is suitable for high-mix, small-lot printing.

In both the printing process by the multi-pass and the rewinding process, the base material is left as it is, and the same path is straightened.
Since it passes in the opposite direction, the intermediate drying unit can be effectively used and the drying capacity can be enhanced. In addition, since it is dried by both direct heating with a heater roller and hot air blowing, high drying efficiency, compactness, and energy saving can be achieved.
Further, it is possible to prevent blocking of the printing surface, peeling of the ink layer due to this, color transfer, and stain generation.

The base material is mainly conveyed by the heater roller,
Since it is driven, the contact length and frictional force with the base material are large, the base material can be driven accurately and stably, and the registration (form) accuracy is high even in multi-pass printing.

[Brief description of drawings]

FIG. 1 is an overall side view of an embodiment of a rotary screen printing machine according to the present invention.

[Explanation of symbols]

 1 Base Frame 2 Base Material 3 Core 4 Guide Roller 10 Unwinding Device 11 Unwinding Frame 12 Unwinding Motor 13 Roller Chain 14 Powder Clutch 15 Tension Sensor 16 Edge Sensor 20 Printing Unit 21 Rotary Screen 22 Squeegee 23 Counter Roller 24 Cooling Roller 24A Gear 25 Timing Pulley 26 Timing Belt 27 Rotary Screen Drive 28 Pinch Roller 28A Air Cylinder 29 Cooling Unit 30 Drive 31 Drive Motor 32 Timing Belt 33 Line Shaft 34 Worm Speed Reducer 35 Gear 40 Intermediate Drying Unit 41 Heater Roller 41A Heater Roller Shaft 42 Timing Pulley 43 Heat source device 44 Blower fan 45 Duct 46 Nozzle 50 Winding device 5 1 Winding frame 52 Winding motor 53 Roller chain 54 Powder clutch 55 Tension sensor 56 Edge sensor.

Claims (4)

[Claims] 1. A printing unit including a rotary screen and a counter roller, a heater roller, and a hot air blowing section around the heater unit are provided between a substrate rewinding device capable of reversing forward and backward and a printed matter winding device capable of reversing forward and backward. At least one pair of intermediate drying units are arranged, the rotary screen, the counter roller, and the heater roller are driven at a synchronized speed, and the base material is supplied to this with a constant tension, and the ink layer applied on the base material is removed. Drying by a heater roller and hot air blowing, the dried printed matter is wound up with a constant tension, and the base material unwinding device, the printed matter winding device, and the drive system of the printing unit and the drying unit are reversed, and the base material is In this state, the printed material is rewound by passing through the same route in the opposite direction, and if necessary, the substrate unwinding device and the printed product winding device. A rotary screen printing method, characterized in that the printing system and the drive system of the drying unit are rotated in the forward direction to perform multi-pass printing. 2. A cooling unit comprising at least one cooling roller and a pinch roller that presses a base material against the cooling roller is disposed on the winding device side of the intermediate drying unit, and the printed matter after drying is wound up. The rotary screen printing method according to claim 1, wherein the rotary screen printing is performed. 3. An intermediate drying unit is arranged above the printing unit, the heater roller has a diameter larger than those of the rotary screen and the counter roller, and the back surface of the printing substrate extends over a length of more than half the circumference of the heater roller. The rotary screen printing method according to claim 1, wherein the rotary screen printing is carried out. 4. A base material unwinding device capable of rotating in the forward and reverse directions, a tension sensor and a tension applying device provided on the unwinding side of the unwinding device, a rotary screen and a counter roller, and printing ink on the base material. At least one printing unit to be applied, at least one intermediate drying unit that is provided subsequent to each printing unit and that includes a heater roller that contacts the back surface of the printing substrate and a hot air blowing section around the heater roller, and each intermediate drying unit. At least one cooling unit, which is provided subsequent to the unit and includes at least one cooling roller and a pinch roller that presses the base material against the cooling roller, a rotary screen, a counter roller, a heater roller, and a cooling roller at a synchronized speed. Drive system for forward / reverse driving with the feed of the cooling unit It is composed of a tension sensor and a tension applying device provided on the delivery side, and a printed matter winding device capable of reversing forward and backward. A rotary screen printing device capable of rewinding a printed matter and performing normal rotation of a substrate unwinding device, a printed matter winding device, and a drive system of a printing unit and a drying unit to perform printing and multi-pass printing.