JP2713645B2 - Corrugator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a corrugator for producing corrugated cardboard sheets.

(Prior Art) FIG. 5 shows a part of a conventional corrugator, in which a single-faced corrugated cardboard sheet 1 made of a single facer (not shown) in a preceding process is provided with a starch paste by a glue machine 14 on the top of the corrugated core paper. 13 is applied and enters the double facer 5. Here, the single-sided corrugated cardboard sheet 1 is a sheet to which the back liner paper 1 'and the corrugated core paper 1 "are adhered.

On the other hand, the front liner 2 is preheated by the preheater 4 and similarly enters the double facer 5. The single-faced cardboard sheet 1 and liner 2 in the double facer 5
In the case of, the belt is driven between a belt 8 driven by a roll 12 and a heating box 9, and further transported while being pressed by weight rolls 10 arranged on the back side of the belt 8. When the single-sided corrugated cardboard sheet 1 and the front liner 2 pass through the heating part 6, the attached starch paste is gelatinized by the heating of the heating box 9 having a high-temperature steam inside, and the corrugated single-sided corrugated cardboard sheet 1 is corrugated. The corrugated top of the core paper 1 "and the front liner 2 are bonded to form a double-faced corrugated cardboard sheet 3. The double-faced corrugated cardboard sheet 3 is pressed by the weight roll 10 between the belt 8 and the lower belt 11 in the following cooling part 7. And transported to the next step.

In the next step, processing such as scoring and cutting is performed by a device (not shown), and then, in the final step, the pieces are stacked into corrugated cardboard in a smooth piece shape and discharged.

(Problems to be Solved by the Invention) Although the double-faced corrugated cardboard sheet 3 is manufactured in the above process,
The conventional corrugator has the following problems. That is, as can be seen in the above manufacturing process, in the corrugated cardboard sheet, the absorption and release of water are repeated in a complicated manner until the bonding. This is not only due to forced water application or drying by gluing or heating, but also reabsorption of water released during preheating drying, or absorption and release of water in the atmosphere. In the corrugated cardboard sheet, the sheet discharged into the atmosphere is warped due to the water-containing state of the front and back liners 2, 1 'when the single-faced cardboard sheet 1 and the front liner 2 are completely bonded in the double facer. This has been a major concern of corrugated cardboard manufacturers because warpage deformation does not provide corrugated cardboard quality.

As shown in FIG. 6, the warpage of the cardboard appears as an upper warp (b) and a lower warp (c) in the best smooth state (a). The warp may be deformed in the paper flow direction other than the warp as shown in the drawing. However, paper generally deforms more in the width direction than in the flow direction,
Warpage in the width direction is most likely to occur, which is regarded as a problem. This is because the expansion and contraction ratio of the paper due to moisture is very small, about 1/4 to 1/5 in the flow direction with respect to the width direction 1.

The deformation as shown in FIG. 6 (b) is apt to occur when the moisture on the front liner 2 side is greater than the moisture on the back liner 1 'side in the process up to bonding. Conversely, it tends to occur when the back liner 1 'side has a large amount of moisture. In order to prevent such a warp deformation, some conventional corrugators include a device for applying moisture to the single-faced corrugated cardboard sheet 1 or the front liner 2 before entering the double facer. However, conventional corrugators do not have a means for detecting warpage deformation, and there is no control means based thereon.Therefore, an operator examines a discharged cardboard paper piece for a warpage deformation of a corrugated cardboard, and then activates a watering device. The reality is that they try to do it.

According to the above-described conventional corrugator, it is not possible to quickly prevent warpage deformation. Further, in the case of a short lot of production sheets, prevention adjustment may not be in time. Therefore, there have been problems such as the production of defective sheets being forced to some extent, and the necessity of arranging skilled workers.

An object of the present invention is to provide a corrugator that can solve the above-mentioned conventional problems by controlling the output of an induction heating coil in accordance with the amount of warpage of a corrugated cardboard sheet in the width direction.

(Means for Solving the Problems) For this reason, the present invention relates to an apparatus for manufacturing a double-sided cardboard sheet by bonding a single-sided cardboard sheet and liner paper.
In the heating part of the device, a heating box that uniformly heats the corrugated cardboard sheet in the width direction and an induction heating coil that is divided into a plurality of pieces in the width direction and placed close to it are independently controlled. A possible heating plate is provided, and on the downstream side of the heating part, a moisture detecting device sandwiching the corrugated cardboard sheet, a device for calculating the amount of warpage of the corrugated cardboard sheet by a signal from the detecting device, A device for controlling the heating plate by a signal is provided, which is used as means for solving the problem.

(Operation) By arbitrarily changing the temperature of the heating plate, the amount of heat transfer between the corrugated cardboard sheet and the heating plate can be controlled. That is, when the heat transfer amount is increased by increasing the temperature of the heating plate, the temperature of the corrugated cardboard sheet is increased, and the water content of the back liner is reduced. In the present invention, the water content of the back liner is changed by changing the water content. By controlling the moisture balance between the liner and the back liner, the amount of warpage of the corrugated cardboard sheet is controlled. With a conventional steam-heated heating box, it is difficult to quickly control the temperature in the width direction. For this reason, in the present invention, a heating box that uniformly heats in the width direction and a heating plate in which high-frequency induction coils capable of controlling the amount of heating in the width direction are arranged at an appropriate pitch are combined to arbitrarily apply a cardboard sheet in the width direction. Control the amount of heat transfer.

(Embodiments) The present invention will be described below with reference to the embodiments in the drawings.
4 show an embodiment of the present invention, wherein 1 is a single-sided corrugated cardboard sheet, 1 'is a back liner paper, 1 "is a corrugated core paper, 2 is a liner, 3 is a double-sided corrugated cardboard sheet, 4 is a preheater, and 5 is a preheater. Double facer, 6 is heating part, 7 is cooling part, 8 is belt, 9 is heating box, 10
Is a weight roll, 11 is a lower belt, 12 is a roll, 13 is starch paste, and 14 is a glue machine, which are the same as the conventional one shown in FIG.

By the way, heating part 6 is double-sided cardboard sheet 3
Heating box 9 that heats the air with steam uniformly in the width direction
And one or more heating plates 20, and a plurality of induction heating coils 21 are arranged close to the heating plate 20 so that the heating plate 20 can be arbitrarily heated in the width direction. FIG. 2 shows a specific installation example, and FIG. 4 shows another embodiment in which a coil is installed from above a belt 8.

Above and below the double-faced corrugated cardboard sheet 3 on the cooling part 7 exit side of the double facer 5, sensors 23 and 23 'for measuring the moisture of the upper liner and the lower liner are provided. Moisture meter can be applied,
The surface moisture of the front liner and back liner can be measured. The sensors 23 and 23 'may be provided in plural numbers in the width direction, or may be fixed to a support beam capable of traversing in the width direction to measure upper and lower width direction moisture.

Also, receiving the output signals of the moisture sensors 23 and 23 ', calculate the amount of warpage of the corrugated cardboard sheet caused by the water difference ε between the upper and lower liners of the water, and calculate the amount of heating of the lower liner to minimize the amount of warpage. And an inverter control unit 22 that receives an output signal from the arithmetic unit 24, controls the output of the high-frequency induction heating coil 21, and operates the coil. The high-frequency induction heating coil 21 is provided with an object to be heated (heating plate 20) by passing an alternating current through the coil.
It is well known that an eddy current is generated on a surface and heat is generated by the loss of the eddy current. The control of the heating amount by the coil can be easily performed by duty ratio control (obtaining the required power by changing the ON-OFF ratio at minute time intervals) or the like. In FIG. 1, the heating box 9 is provided in the first half and the heating plate 20 is provided in the second half. However, the order and the load ratio are not limited to those in FIG. A heating box may be provided in the latter half.

(Effect of the Invention) Since the present invention is configured as described in detail above, the amount of warpage of the corrugated cardboard sheet can be predicted online, and both the warpage in the flow direction and the warp in the width direction of the corrugated cardboard sheet are suppressed. I can do it. Therefore, the productivity is remarkably improved, and it is possible to minimize the waste of corrugated cardboard sheets.

[Brief description of the drawings]

FIG. 1 is a side sectional view including a circuit diagram of a corrugator according to an embodiment of the present invention, FIG. 2 is a sectional view showing one of arrangement examples of a heating plate and an induction heating coil of the present invention, and FIG. 2 is a cross-sectional view taken along line A-A of FIG. 2, FIG. 4 is a cross-sectional view showing an example of disposing a heating plate and an induction heating coil different from FIG. 3, FIG. 5 is a side cross-sectional view of a conventional double facer, and FIG. It is explanatory drawing which shows the state of the curvature of the cardboard sheet. Description of main parts in the drawing 1. Single-sided cardboard sheet 2. Liner 3. Double-sided cardboard sheet 5 Double facer 6 Heating part 7 Cooling part 9 Heating box 20 Heating plate 21 …… High frequency induction heating coil 22 …… Inverter controller 23 …… Moisture sensor

Claims (1)

(57) [Claims] 1. An apparatus for manufacturing a double-sided corrugated cardboard sheet by bonding a single-sided corrugated cardboard sheet and liner paper, wherein a heating box for uniformly heating the corrugated cardboard sheet in a width direction is provided on a heating part of the apparatus. A heating plate is provided which is capable of independently controlling the induction heating coil disposed in close proximity to the heating part. A corrugator comprising a device, a device for calculating the amount of warpage of a cardboard sheet based on a signal from the detecting device, and a device for controlling the heating plate based on a signal from the calculating device.