JP2018114734A - Double facer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double facer which can reduce or prevent deposition of foreign matters derived from components involved in a corrugated cardboard base paper on a surface of a heating platen.SOLUTION: The double facer 10 includes: a transportation belt 3 which has a pressure apparatus and transports a single-sided corrugated cardboard 1 and a front liner 2 being laminated together while applying pressure from the above; and a heating platen group 4 which forms a guideway of the front liner and heats a paste liquid applied on apexes of the single-sided corrugated cardboard for gelatinization. While the single-sided corrugated cardboard and the front liner are sandwiched and transported between the transportation belt having the pressure apparatus and the heating platen group, the paste liquid is gelatinized, and the single-sided corrugated cardboard and the front liner are bonded together with its adhesive force to give a corrugated cardboard. The double facer 10 contains a temperature measurement device 5 which measures the temperature of the front liner running over the heating platen group, and controls the temperature of the heating platen group based on the temperature of the front liner measured by the temperature measurement device in a manner that the maximum temperature of the front liner does not exceed a predetermined upper limit temperature.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a double facer in a corrugated board manufacturing apparatus.

  In general, a corrugator corrugator manufacturing apparatus includes a single facer for producing a single-sided corrugated sheet by forming a core paper into a corrugated shape and bonding it to a back liner, and a single-sided corrugated sheet produced from the single facer. And a double facer for producing a double-sided cardboard sheet (hereinafter also simply referred to as “corrugated cardboard sheet”) by bonding the liner.

  For example, in the double facer 100 disclosed in Patent Document 1, as shown in FIG. 8, the upper and lower single-sided corrugated cardboard sheets 101 and the lower front liner 102 are pressed up and down with a weight roll 103 or the like from above. A heating belt group 105 that forms a traveling path of the front liner 102 and heats the paste applied to the top of the single-sided corrugated cardboard sheet 101 to be gelatinized by heating. And. According to this double facer 100, while the single-sided corrugated cardboard sheet 101 and the front liner 102, which are stacked one above the other, are sandwiched and conveyed between the conveying belt 104 with a pressure device and the heating plate group 105, the heating plate group 105 is provided. The paste liquid is gelatinized by the heat from the front liner 102 that is heated in contact with the sheet, and the single-sided cardboard sheet 101 and the front liner 102 are bonded by the adhesive force to produce a cardboard sheet.

  Incidentally, in recent years, in the production of corrugated cardboard sheets, production orders for a small variety of products have increased, and the need to increase the productivity of the corrugated cardboard sheet manufacturing apparatus has led to a demand for increasing the conveyance speed of corrugated cardboard sheets with a double facer. However, if the conveyance speed of the corrugated cardboard sheet with the double facer is increased, the supply of heat from the heating plate group necessary for gelatinizing the glue solution will be insufficient, and it will be easy to cause poor bonding between the single-sided cardboard sheet and the front liner. There was a problem.

  In order to cope with this problem, for example, Patent Document 2 discloses that the heat plate is thinned to improve the heat transfer efficiency with respect to the corrugated cardboard sheet traveling on the upper surface of the heat plate, facilitate the manufacture of the heat plate, and generate the generated drain. Has disclosed a double facer hot platen that can be discharged without delay so as not to lower the heating capacity. By using the double facer hot platen, even if the conveyance speed of the cardboard sheet traveling on the hot platen is increased, the shortage of supply of heat necessary for bonding the single-sided cardboard sheet and the front liner is eliminated, Stabilization of the bonding becomes possible.

JP, 2006-144881, A JP 2008-55778 A

  However, when the above-described hot platen with high heat transfer efficiency is used, the temperature of the single-sided corrugated cardboard sheet and the front liner becomes excessive, the thermoplastic resin components contained in those base papers are eluted, In some cases, the phenomenon of adhering to the surface occurred. When this foreign matter is transferred from the hot platen to the front liner and the corrugated sheet with the foreign matter attached is shipped, not only the printing on the corrugated cardboard sheet may cause poor print quality, but also inside the box of the corrugated cardboard sheet. There is a possibility that foreign matter may adhere to the contents to be packed, and it was necessary to reduce or prevent the foreign matter from adhering to the hot platen.

  Therefore, when the inventor of the present application analyzed the component of the foreign matter using infrared spectroscopy, the main component was polystyrene, which is a thermoplastic resin contained in a corrugated cardboard base paper (particularly, a front liner base paper). There was found. In addition, when the inventors of the present application measure the temperature of the front liner running on the hot platen in the double facer using the hot platen having the above configuration, if there is much foreign matter adhering to the hot platen, the temperature of the front liner However, it exceeded 150 ° C at the maximum. On the other hand, when almost no foreign matter adhered to the hot platen, the temperature of the front liner was about 130 ° C. at the maximum. That is, the maximum temperature of the heated surface liner is about 20 ° C. higher in the double facer where much foreign matter adheres than in the double facer that does not.

  In general, when the temperature is lower than the glass transition point that is the boundary, the amorphous portion of the polymer compound has a low molecular mobility and becomes a glass state. However, as the temperature rises above the glass transition point, the viscosity decreases, It has the property of having a high mobility and a rubber state. In the case of polystyrene, which is the main component of foreign matter, there is a report that the viscosity decreases exponentially and the molecular mobility increases as the temperature rises from around the glass transition point of 100 ° C. Refer to Fig.2 of "Melting viscosity of polystyrene with narrow distribution": Published in Polymer Journal, Vol.33, No.12, p717-721, published in December 1976).

  Based on the above facts, when the inventor of the present application uses the above-described hot platen with high heat transfer efficiency, the surface liner is heated in a higher temperature range than before, and the component mainly composed of polystyrene contained in the surface liner base paper. Was dissolved and adhered to the surface of the hot platen as a foreign substance.

  The present invention has been made based on the above consideration results, and an object of the present invention is to provide a double facer that can reduce or prevent the adhesion of foreign substances derived from components contained in a corrugated board base paper to the surface of a hot platen.

In order to achieve the above object, a double facer according to the present invention has the following configuration.
(1) A conveying belt with a pressure device that conveys a single-sided corrugated cardboard sheet positioned above and a front liner positioned below from above while being superposed vertically and a travel path for the front liner is formed. And a heating platen that heats and pastes the paste applied to the top of the single-sided cardboard sheet, and the single-sided cardboard sheet and the front liner, which are stacked one above the other, are transported belts with the pressure device. And the hot platen group, the paste liquid is gelatinized by the heat from the surface liner that is heated in contact with the hot platen group, and the single-sided corrugated cardboard is bonded with the adhesive force. A double facer in which a sheet and the front liner are bonded to produce a cardboard sheet,
A temperature measuring device for measuring the temperature of the front liner traveling on the heating plate group, and the table measured by the temperature measuring device so that the maximum temperature of the front liner does not exceed a predetermined upper limit temperature; The temperature of the heating plate group is controlled based on the temperature of the liner.

  According to the above feature, the maximum temperature of the front liner traveling on the hot platen does not rise beyond a predetermined upper limit temperature, so that elution of components contained in the corrugated cardboard base paper (particularly the front liner base paper) can be suppressed, The phenomenon that the component adheres to the surface of the hot platen as a black foreign substance can be reduced or prevented.

  That is, since the maximum temperature of the front liner traveling on the hot platen group does not exceed the predetermined upper limit temperature, even when using a hot platen with high heat transfer efficiency, the polystyrene contained in the front liner base paper is the main component. It is difficult for the components to be eluted. Here, the predetermined upper limit temperature is set based on the type of cardboard sheet base paper (particularly, front liner base paper), the percentage of used paper, and the like. Therefore, it is possible to suppress the generation amount of foreign matters that are derived from components contained in the corrugated board base paper (particularly, the front liner base paper) and adhere to the hot platen. In addition, the temperature measuring instrument measures the temperature of the front liner that runs on the hot platen group, so it can measure the temperature of the front liner that has been heated by the hot platen group and has reached the maximum temperature, which can cause the generation of foreign matter. It is easy to manage the temperature of the resulting hot panel group. Furthermore, by controlling the temperature of the hot platen group, even if a hot platen with high heat transfer efficiency is used, it is possible to improve the productivity of corrugated cardboard sheets while enabling good bonding without causing foreign matter. . As a result, according to the present invention, it is possible to provide a double facer that can reduce or prevent the adhesion of foreign substances derived from the components contained in the corrugated board base paper to the surface of the hot platen.

  Depending on the type of single-sided cardboard sheet or front liner, the position where the temperature of the front liner reaches the maximum temperature when heated by the hot platen group may differ, so measure the temperature of the front liner traveling on the hot platen group It is preferable to arrange a plurality of temperature measuring devices along the conveying direction of the front liner.

(2) In the double facer described in (1),
At least one of the temperature measuring devices is disposed in the vicinity of the hot platen installed on the upstream side in the hot plate group.

  In general, the temperature of the front liner heated by the hot platen group tends to reach the maximum temperature upstream of the hot platen group. Therefore, according to the above feature, the temperature measuring device increases the maximum temperature of the front liner. It can be measured reliably. In other words, the maximum temperature of the front liner can be measured more reliably without increasing the number of temperature measuring instruments installed in the hot plate group in which many hot plates are arranged from the upstream side to the downstream side. Can do. More specifically, the hot platen group is divided into a plurality of small groups from the upstream side toward the downstream side, and temperature control is performed for each of the small groups, and the temperature measuring instrument is the first arranged at the most upstream side. It is preferable to arrange at least one in the vicinity of a group of hot plates.

(3) In the double facer described in (1) or (2),
The temperature measuring device is a non-contact thermometer that measures the temperature of the front liner from a gap between adjacent hot plates in the hot plate group.

  According to the above feature, the temperature of the front liner traveling on the hot platen group can be measured in a non-contact manner, so that it can be measured without damaging the front liner. In addition, since the temperature measuring device is a non-contact thermometer, it can be installed away from the heated hot plate, and it is effective that the temperature sensor in the temperature measuring device is deteriorated or damaged by the heat of the hot plate. Can be avoided. In addition, the temperature measuring device measures the temperature of the front liner from the gap between adjacent heating plates in the heating plate group, so that it is not necessary to perform drilling or the like on the heating plate itself and can be easily installed. . The non-contact thermometer is preferably a radiation thermometer, for example, and is preferably provided with an air purge unit or the like that prevents dust and the like from entering the measurement range (infrared irradiation range) of the radiation thermometer.

(4) In the double facer described in any one of (1) to (3),
The upper limit temperature is changed according to a basis weight of the front liner in a production order.

  In general, when the basis weight, which is the weight per square meter, of the corrugated cardboard sheet decreases, the ratio of used paper increases. A corrugated cardboard sheet having a high wastepaper ratio and a small basis weight tends to have more thermoplastic resin components contained in the corrugated cardboard sheet than a corrugated cardboard sheet having a low wastepaper ratio. Therefore, according to the said characteristic, the generation amount of the foreign material adhering to the surface of a hot platen can be reduced further by changing a predetermined | prescribed upper limit temperature according to the basic weight of the surface liner in a production order. More specifically, the upper limit temperature with respect to the maximum temperature of the front liner traveling on the hot platen group is set based on the amount of foreign matter adhered previously verified, but within the range of 125 ° C. to 135 ° C. It is preferable to set the upper limit temperature lower as the amount decreases.

(5) In the double facer described in any one of (1) to (4),
The temperature of the heating plate group is controlled by adjusting the saturated vapor pressure of the steam supplied to each heating plate with a pressure adjusting valve.

  According to the above feature, since the temperature of the hot platen group is controlled by adjusting the saturated vapor pressure of the steam supplied to each hot platen, the temperature of the hot platen can be increased or decreased proportionally. Therefore, it is easy to maintain the temperature of the heating plate group within an appropriate range, and the generation of foreign matters can be further reduced or prevented.

(6) In the double facer described in any one of (1) to (5),
Each of the hot plates constituting the hot plate group is made of steel.

  According to the above feature, the thermal conductivity is higher than that of conventional cast iron, and when the maximum temperature of the front liner is about to rise above the predetermined upper limit temperature, it can be quickly returned to the upper limit temperature or lower. Moreover, since each hot platen is made of steel, heat resistance and wear resistance can be improved as compared with conventional cast iron.

(7) In the double facer described in (6),
The thickness between the heat medium supply pipe formed inside the hot plate and the upper surface of the hot plate is set to 10 mm or less.

  According to the above feature, the heat medium supply pipe formed inside the heat plate can be formed at a position close to the upper surface of the heat plate, and the temperature of the heat plate group can be quickly controlled within an appropriate range. it can. Therefore, the temperature of the front liner traveling on the hot platen group does not become excessive, and it becomes easier to further reduce or prevent the adhesion amount of foreign matters.

  ADVANTAGE OF THE INVENTION According to this invention, the double facer which can reduce or prevent the adhesion of the foreign material derived from the component contained in the corrugated board base paper with respect to the surface of a hot platen can be provided.

It is a schematic block diagram of the double facer concerning this embodiment. FIG. 2 is a main cross-sectional view on the upstream side of the double facer shown in FIG. 1. It is AA sectional drawing shown in FIG. It is detail drawing of the hot platen in the double facer shown in FIG. (A) is a top view including the partial cross section of a hot platen, (B) is a longitudinal cross-sectional view of a hot platen. FIG. 2 is a layout diagram of temperature measuring devices in the double facer shown in FIG. 1. It is a schematic diagram explaining the phenomenon in which the component contained in a surface liner elutes in response to the heat from a hot platen, and a foreign material generate | occur | produces. In the double facer of this embodiment, it is a graph showing the measurement result of the adhesion amount of the foreign material with respect to a heat disc, and the graph showing the measurement result of the adhesion amount of the foreign material with respect to a heat disc in the conventional double facer. It is a schematic block diagram of the conventional double facer.

  Next, a double facer according to an embodiment of the present invention will be described in detail with reference to the drawings. The structure of the double facer according to the present embodiment and the operation method thereof will be described, and the measurement result of the amount of foreign matter attached to the surface of the hot platen will be described.

<Double facer structure and its operation method>
First, the structure of the double facer according to the present embodiment and the operation method thereof will be described with reference to FIGS. FIG. 1 shows a schematic configuration diagram of a double facer according to the present embodiment. FIG. 2 shows a main sectional view on the upstream side of the double facer shown in FIG. FIG. 3 is a cross-sectional view taken along the line AA shown in FIG. FIG. 4 shows a detailed view of the hot platen in the double facer shown in FIG. 4A shows a plan view including a partial cross section of the hot platen, and FIG. 4B shows a vertical cross sectional view of the hot platen.
FIG. 5 shows a layout diagram of temperature measuring devices in the double facer shown in FIG. FIG. 6 is a schematic diagram for explaining a phenomenon in which a component contained in the front liner is eluted by receiving heat from the hot platen and foreign matter is generated.

  As shown in FIGS. 1 to 6, the double facer 10 according to the present embodiment conveys a single-sided corrugated sheet 1 located above and a front liner 2 located below in a state where they are stacked one above the other while being pressurized from above. And a heating plate group 4 that forms a traveling path of the front liner 2 and heats the paste liquid n applied to the step top portion 111 of the single-sided corrugated cardboard sheet 1 to gelatinize it. While the single-sided cardboard sheet 1 and the front liner 2 superimposed on each other are sandwiched and conveyed between the conveying belt 3 with a pressurizing device and the heating plate group 4, the temperature rises in contact with the heating plate group 4. It is a double facer in which the paste liquid n is gelatinized by the heat from the front liner 2 and the single-sided cardboard sheet 1 and the front liner 2 are bonded by the adhesive force to produce the cardboard sheet 20.

  The double facer 10 also includes a temperature measuring device 5 (5a, 5b, 5c) for measuring the temperature of the front liner 2 traveling on the heating plate group 4, and the maximum temperature of the front liner 2 exceeds a predetermined upper limit temperature. Therefore, the temperature of the hot platen group 4 is controlled based on the temperature of the front liner 2 measured by the temperature measuring device 5. When the temperature of the hot platen group 4 becomes excessive, a component mainly composed of polystyrene contained in the front liner base paper is eluted by the heat h from the hot platen, and adheres to the upper surface 44 of the hot platen as particulate foreign matter p. This is because it is likely to occur (see FIG. 6). The predetermined upper limit temperature is preferably changed according to the basis weight of the front liner 2 in the production order. Specifically, the upper limit temperature with respect to the maximum temperature of the front liner 2 traveling on the hot platen group 4 is set based on the amount of adhesion of the foreign matter p verified in advance, but within the range of 125 ° C. to 135 ° C., It is preferable to set the upper limit temperature lower as the basis weight of the liner 2 becomes smaller.

  As shown in FIGS. 1 and 2, the conveyor belt 3 with a pressure device includes a belt body 3 </ b> A and a pressure device 3 </ b> B. The belt main body 3A is stretched by a driving roller (not shown) disposed on the downstream side in the transport direction (the direction of arrow F) and a driven roller 34 disposed on the upstream side in the transport direction. The belt body 3A moves in the transport direction by the rotation of the drive roller, and transports the single-sided cardboard sheet 1 and the front liner 2 in the transport direction. The single-sided corrugated cardboard sheet 1 is conveyed from obliquely upward on the upstream side so as to come into contact with the outer peripheral surface of the belt main body 3A wound around the driven roller 34. The width dimension of the belt main body 3A is formed to be equal to or greater than the maximum width dimension of the single-sided cardboard sheet 1 to be conveyed.

  The pressurizing device 3B in the transport belt 3 with the pressurizing device includes a plurality of roll-shaped pressurizing bodies 3a, 3b, and 3c disposed on the upstream side and a plurality of plate-shaped pressurizing disposed on the midstream side and the downstream side. 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, and 3m. Further, the roll-shaped pressurizing bodies 3a to 3c and the plate-shaped pressurizing bodies 3d to 3m are respectively heated plates 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j that constitute the heated plate group 4. Corresponding to 4k, 4l, 4m, it is formed to be movable in the vertical direction. Adjusting the amount of heat transferred from the respective hot plates 4a to 4m to the single-sided corrugated cardboard sheet 1 and the front liner 2 by moving the roll-shaped pressure bodies 3a to 3c and the plate-like pressure bodies 3d to 3m in the vertical direction. Can do.

  As shown in FIGS. 2 and 3, each of the roll-shaped pressurizing bodies 3 a to 3 c is configured as follows. That is, a plurality of roll bodies 31 that pressurize the belt body 3A from above are arranged in parallel in a direction (left-right direction) orthogonal to the transport direction, and both end shaft portions 311 and 311 of each roll body 31 are interposed via the bearing portions 312. It is supported by the connecting plate 32 so as to be rotatable. The axial length of the outer peripheral surface of the roll that forms the pressing surface of the roll body 31 is formed substantially the same as the width dimension of the belt main body 3A and the heating plates 4a to 4m. The connecting plate 32 is fastened to a rack plate 321 formed to be movable up and down. The rack plate 321 is connected to a geared drive motor (not shown). When the drive motor operates, the roll-shaped pressurizing bodies 3a to 3c move up and down horizontally, and the single-sided cardboard sheet 1 and the front liner 2 are added onto the heating plates 4a to 4m via the belt body 3A. The applied pressure can be adjusted.

  Moreover, as shown in FIG. 1, FIG. 2, each plate-shaped pressurization body 3d-3m is comprised as follows. That is, a plate-like body 33 that pressurizes the belt main body 3A from above is continuously arranged with a predetermined gap along the conveyance direction, and the upper end portion of the plate-like body 33 moves up and down horizontally. It is supported. The link mechanism 35 is connected to a cylinder body 34 that expands and contracts in the vertical direction. Further, a spring member 36 is attached to the plate-like body 33 for vibration absorption and the like. When the rod of the cylinder body 34 expands and contracts, the plate-like body 33 moves up and down horizontally and pressurizes the single-sided cardboard sheet 1 and the front liner 2 onto the heating plates 4a to 4m via the belt body 3A. The pressure can be adjusted.

  Further, the front liner 2 is conveyed onto the heating platen group 4 from the obliquely lower side on the upstream side via the preheater roll 21, the guide roll 22, and the guide plate 23 disposed below the driven roller 34. A heat medium such as saturated steam is supplied to the preheater roll 21 to preheat the front liner 2. A cylinder body 24 that expands and contracts in the vertical direction is connected to the downstream side of the guide plate 23. When the cylinder body 24 extends in an emergency, the guide plate 23 can be moved downward with the upstream side serving as a fulcrum.

  Moreover, each heating board 4a-4m which comprises the heating board group 4 is arrange | positioned continuously, having a predetermined | prescribed clearance gap along a conveyance direction. Each of the heating plates 4a to 4m is horizontally supported at substantially the same height via a plurality of support bolts 47 that are erected on a frame member 48 that is disposed below and extends in the left-right direction. Further, as shown in FIG. 4, the heating plates 4 a to 4 m are steel plate-like bodies formed in a rectangular shape, and a cylindrical heating medium supply conduit 42 through which saturated water vapor or the like passes is formed. ing. It is preferable that the minimum wall thickness t1 between the heat medium supply pipe 42 and the heating platen upper surface 44, which is the surface running surface of the front liner, be within 10 mm.

  The heat medium supply pipes 42 are formed in parallel in the left-right direction, and are alternately communicated so that the pipe lines adjacent in the transport direction are folded at the left and right ends of the heating plates 4a to 4m. The left and right ends of the hot plates 4a to 4m are sealed with lids 45 and 46, respectively. Therefore, a heat medium such as saturated steam flowing in the heat medium supply pipe 42 heats the heating plates 4a to 4m substantially uniformly while flowing in a zigzag direction in the left-right direction.

  As shown in FIG. 3, the temperature of the hot platen group 4 is controlled by adjusting the saturated vapor pressure of the steam J supplied to the hot plates 4 a to 4 m with a pressure adjusting valve 7. The pressure adjustment valve 7 may be an electromagnetic drive pressure adjustment valve or an air drive pressure adjustment valve. Further, the hot platen group 4 can be divided into a plurality of small groups from the upstream side toward the downstream side, and temperature control can be performed for each of the small groups. For example, as shown in FIG. 1, the saturated vapor pressures of the first to fifth hot plates 4a to 4e (first group) on the upstream side are set to 0.7 to 0.8 MPa, and the sixth To the ninth hot platen 4f to 4i (second group) is set to 0.5 to 0.6 MPa, and the tenth to thirteenth hot plates 4j to 4m (third group). ) Is set to 0.3 to 0.5 MPa.

  That is, the saturated vapor pressure of the steam J supplied to the hot platen group 4 is adjusted to be highest on the upstream side, and the saturated vapor pressure of the steam J supplied to the hot platen group 4 is gradually increased from the midstream side toward the downstream side. It is preferable to control so that the temperature of the heating platen group 4 is highest at the upstream side and gradually decreases toward the downstream side or changes at the same level. By controlling the temperature of the hot platen group 4 in this way, the pasting of the paste liquid n in the single-sided cardboard sheet 1 and the front liner 2 traveling on the hot platen group 4 is completed at an early stage to stabilize the bonding. At the same time, the temperature of the single-sided corrugated cardboard sheet 1 and the front liner 2 can be prevented from becoming excessive, and the generation of foreign matter p can be reduced or prevented.

  Moreover, as shown in FIGS. 1-4, the supply port 41 and the discharge port 43 of the heat-medium supply pipe line 42 are formed in the left-right diagonal position of the upstream and downstream on the lower surface of each heating board 4a-4m. ing. Moreover, the supply port 41 and the discharge port 43 in the adjacent hot plates 4a-4m are arrange | positioned by alternately replacing the upstream downstream and the left end right end. For example, in the second hot platen 4b on the upstream side, the supply port 41 is disposed at the left end on the upstream side, and the discharge port 43 is disposed on the right end on the downstream side. In the third heating platen 4c, the supply port 41 is disposed at the right end on the downstream side, and the discharge port 43 is disposed on the left end on the upstream side.

  As described above, by arranging the supply port 41 and the discharge port 43 in the adjacent heating plates 4a to 4m alternately at the upstream downstream and the left end and the right end, the left and right deviation of the temperature distribution in the heating plate group 4 is as much as possible. It becomes possible to decrease. This also stabilizes the bonding between the single-sided corrugated cardboard sheet 1 and the front liner 2, and prevents the temperature of the single-sided cardboard sheet 1 and the front liner 2 from becoming excessive, thereby reducing or preventing the generation of foreign matter p. be able to.

  As shown in FIGS. 1 and 2, the temperature measuring device 5 (5 a, 5 b, 5 c) that measures the temperature of the front liner 2 traveling on the heating platen group 4 is along the conveying direction of the front liner 2. A plurality are arranged. It is preferable that at least one temperature measuring device 5 is disposed in the vicinity of the heating plate installed on the upstream side of the heating plate group 4. Further, the hot platen group 4 is divided into a plurality of small groups (for example, the first group to the third group described above) from the upstream side to the downstream side, and temperature control is performed for each of the small groups. 5 is preferably arranged in the vicinity of the first group of heating plates 4a to 4e arranged on the most upstream side.

  Specifically, the first temperature measuring device 5a that measures from the gap between the third and fourth heating plates 4c and 4d, the sixth and fourth heating plates 4f and 4g. And a third temperature measuring device 5c for measuring from the gap between the eighth hot platen 4h and the ninth hot platen 4i. As shown in FIG. 5, the temperature measuring device 5 (5 a, 5 b, 5 c) is a non-contact thermometer that measures the temperature of the front liner 2 from the gap between adjacent hot plates in the hot plate group 4. Is preferred. The non-contact thermometer is preferably a radiation thermometer, for example, and an air purge unit 6 or the like for preventing dust and the like from entering the measurement range (infrared irradiation range) 51 of the radiation thermometer is also provided. preferable.

<Measurement result of amount of foreign matter attached>
Next, the double facer according to the present embodiment is compared with the conventional double facer, and the measurement result of the amount of foreign matter attached to the surface of the hot platen will be described with reference to FIG. FIG. 7 shows a graph representing the measurement result of the accumulated amount of foreign matter on the hot plate in the double facer of the present embodiment and a graph representing the measurement result of the accumulated amount of foreign matter on the hot plate in the conventional double facer.

  As shown in FIG. 7, the accumulated amount (%) of foreign matter on the double facer 10 of the present embodiment is represented by a solid line, and the accumulated amount (%) of foreign matter on the conventional double facer is represented by a dotted line. The accumulated amount (%) of foreign matter adhesion of the double facer 10 of the present embodiment is expressed as a ratio (%) when the accumulated amount of foreign matter adhesion (%) of the conventional double facer is 100 (%). Here, the saturated vapor pressure of the steam J supplied to the hot platen group 4 of the double facer 10 of this embodiment for the B flute corrugated cardboard sheet 20 is set to 0.7 MPa in the first group, and the second group is set to The temperature was set to 0.5 MPa, the third group was set to 0.5 MPa, and the hot platen group 4 was controlled to a low temperature. On the other hand, the configuration of the conventional double facer hot platen group is the same as that of the present embodiment, but the saturated vapor pressure of the steam J supplied to the hot platen group is set to 0.9 MPa in the first group, and the second group. Was set to 0.6 MPa, the third group was set to 0.5 MPa, and the hot platen group was controlled to a high temperature.

  As shown in FIG. 7, the accumulated amount of foreign matter in the conventional double facer in which the hot platen group is controlled to a high temperature rises to about 60% on the upstream side (near the first group hot platen), and reaches the midstream side (second It increased to about 100% in the vicinity of the heating plate of the group) and did not substantially change on the downstream side (near the heating plate of the third group). On the other hand, the accumulated amount of foreign matters in the double facer 10 of the present embodiment in which the heat plate group is controlled to a low temperature has increased to about 50% on the upstream side (near the first group of heat plates). In the vicinity of the second group of heating plates) and on the downstream side (near the third group of heating plates), there was almost no change. As a result, in the double facer 10 of the present embodiment in which the hot platen group is controlled to a low temperature, the accumulated amount of foreign matters on the hot platen group is reduced to about ½ as compared with the conventional double facer in which the hot platen group is controlled to a high temperature. It was possible to reduce.

<Effect>
As described above in detail, according to the double facer 10 according to the present embodiment, the temperature measuring device 5 (5a, 5b, 5c) for measuring the temperature of the front liner 2 traveling on the hot platen group 4 is provided. The temperature of the hot platen group 4 is controlled based on the temperature of the front liner 2 measured by the temperature measuring device 5 so that the maximum temperature of the front liner 2 does not exceed a predetermined upper limit temperature. The maximum temperature of the front liner 2 traveling on the vehicle does not exceed a predetermined upper limit temperature. Therefore, the elution of the components contained in the corrugated board base paper (especially the front liner base paper) can be suppressed, and the phenomenon that the eluted components adhere to the surfaces of the hot plates 4a to 4m as black foreign matters p can be reduced or prevented. .

  That is, since the maximum temperature of the front liner 2 traveling on the heat plate group 4 is not increased beyond a predetermined upper limit temperature, even when the heat plates 4a to 4m having high heat transfer efficiency are used, they are included in the front liner base paper. A component mainly composed of polystyrene is not easily eluted. Here, the predetermined upper limit temperature is set based on the type of cardboard sheet base paper (particularly, front liner base paper), the percentage of used paper, and the like. Therefore, it is possible to suppress the generation amount of the foreign matter p that originates from the components contained in the corrugated board base paper (particularly, the front liner base paper) and adheres on the hot plates 4a to 4m. Further, since the temperature measuring device 5 measures the temperature of the front liner 2 traveling on the hot platen group 4, the temperature of the front liner 2 heated to the maximum temperature by the hot platen group 4 can be measured. It is easy to manage the temperature of the hot platen group 4 due to the generation of the foreign matter p. Furthermore, by controlling the temperature of the heat plate group 4, it is possible to produce the corrugated cardboard sheet 20 while enabling good bonding without generating foreign matter p even if the heat plates 4a to 4m having high heat transfer efficiency are used. It can also improve sex. As a result, according to the present embodiment, it is possible to provide the double facer 10 that can reduce or prevent the adhesion of the foreign matter p derived from the components contained in the corrugated board base paper to the surfaces of the hot plates 4a to 4m.

  Further, according to the present embodiment, at least one temperature measuring device 5 is arranged in the vicinity of the heating plates 4 a to 4 e installed on the upstream side in the heating plate group 4. Generally, the temperature of the front liner 2 heated by the hot platen group 4 tends to reach the maximum temperature on the upstream side of the hot platen group 4. The maximum temperature can be measured more reliably. That is, with respect to the hot platen group 4 in which a large number of hot plates 4a to 4m are arranged from the upstream side toward the downstream side, the number of the temperature measuring devices 5 installed can be more reliably increased without increasing the number of installed temperature measuring devices 5. Maximum temperature can be measured.

  Further, according to the present embodiment, the temperature measuring device 5 is a non-contact thermometer that measures the temperature of the front liner 2 from the gap between the adjacent heating plates in the heating plate group 4. The temperature of the traveling front liner 2 can be measured in a non-contact manner, and can be measured without damaging the front liner 2. Moreover, since the temperature measuring device 5 is a non-contact thermometer, it can be installed apart from the heated heating plates 4a to 4m, and the temperature sensor unit in the temperature measuring device 5 is the heat of the heating plates 4a to 4m. Can effectively avoid deterioration and damage. Moreover, since the temperature measuring device 5 measures the temperature of the front liner 2 from the gap between adjacent heating plates in the heating plate group 4, it is not necessary to perform drilling or the like on the heating plate itself and is easily installed. be able to. Since the non-contact thermometer is a radiation thermometer, the surface temperature of the front liner 2 being conveyed can be measured quickly. Moreover, since the air purge unit 6 for preventing dust and the like from entering the measurement range 51 (infrared irradiation range) of the radiation thermometer is provided, the surface temperature of the front liner 2 can be measured with higher accuracy.

  In general, when the basis weight, which is the weight per square meter, of the corrugated cardboard sheet 20 decreases, the ratio of used paper increases. Then, the corrugated cardboard sheet 20 having a high wastepaper ratio and a small basis weight tends to have more thermoplastic resin components contained in the corrugated cardboard sheet 20 than the corrugated cardboard sheet 20 having a low wastepaper ratio. However, according to this embodiment, the upper limit temperature with respect to the maximum temperature of the front liner 2 is changed according to the basis weight of the front liner 2 in the production order. Therefore, by changing the predetermined upper limit temperature according to the basis weight of the front liner 2 in the production order, it is possible to further reduce the amount of foreign matter p adhering to the surfaces of the hot plates 4a to 4m. More specifically, the upper limit temperature with respect to the maximum temperature of the front liner 2 traveling on the hot platen group 4 is set based on the amount of adhered foreign matter verified in advance, but within the range of 125 ° C. to 135 ° C. The generation amount of the foreign matter p can be reduced by setting the upper limit temperature lower as the basis weight of 2 becomes smaller.

  Further, according to the present embodiment, the temperature of the hot platen group 4 is controlled by adjusting the saturated vapor pressure of the steam J supplied to the hot plates 4 a to 4 m with the pressure adjusting valve 7. That is, since the temperature of the hot platen group 4 is controlled by adjusting the saturated vapor pressure of the steam J supplied to the hot plates 4a to 4m, the temperature of the hot plates 4a to 4m can be proportionally increased or decreased. Therefore, it is easy to maintain the temperature of the heating plate group 4 within an appropriate range, and the generation of the foreign matter p can be further reduced or prevented.

  Moreover, according to this embodiment, since each heating board 4a-4m which comprises the heating board group 4 is steel, compared with the conventional cast iron, heat conductivity is high, and the maximum temperature of the surface liner 2 is high. When trying to rise above the predetermined upper limit temperature, the temperature can be quickly returned to the upper limit temperature or lower. Moreover, since each hot platen 4a-4m is made of steel, heat resistance and wear resistance can be improved as compared with the conventional cast iron.

  In addition, according to the present embodiment, since the wall thickness t1 between the heat medium supply pipe 42 formed inside the heating plates 4a to 4m and the heating plate upper surface 44 is within 10 mm, the heat formed inside the heating plates The medium supply line 42 can be formed at a position close to the hot platen upper surface 44, and the upper surface temperature of the hot platen group 4 can be quickly controlled within an appropriate range. Therefore, the temperature of the front liner 2 traveling on the hot platen group 4 does not become excessive, and it becomes easier to further reduce or prevent the adhesion amount of the foreign matter p.

<Modification>
It goes without saying that the above-described embodiment can be variously modified without departing from the gist of the present invention. For example, in the present embodiment, the temperature of the hot platen group 4 is controlled by adjusting the saturated vapor pressure of the steam J supplied to each of the hot plates 4 a to 4 m with the pressure adjusting valve 7. As a result, the temperature of the hot platen group 4 is controlled within a predetermined range, and the pasting of the paste liquid n in the single-sided cardboard sheet 1 and the front liner 2 traveling on the hot platen group 4 is completed at an early stage. While stabilizing, it prevents that the temperature of the single-sided corrugated-cardboard sheet | seat 1 and the front liner 2 becomes excessive, and reduces or prevents generation | occurrence | production of the foreign material p. However, the method is not necessarily limited to the method of controlling the temperature of the heating plate group 4. For example, the pressurizing force is adjusted by moving the roll-shaped pressurizing bodies 3a to 3c and / or the plate-shaped pressurizing bodies 3d to 3m that are the pressurizing devices 3B in the transport belt 3 with the pressurizing device, It is also possible to add a control method for adjusting the amount of heat transmitted from each of the heating plates 4a to 4m to the single-sided cardboard sheet 1 and the front liner 2. By using both the temperature control of the hot platen group 4 and the pressurization control of the pressurizing device 3B, the temperature management of the front liner 2 traveling on the hot platen group 4 can be performed with higher accuracy. It can contribute to suppression.

  The present invention can be used as a double facer in a corrugated sheet manufacturing apparatus.

DESCRIPTION OF SYMBOLS 1 Single-sided cardboard sheet | seat 2 Front liner 3 Conveyor belt with a pressurizer 4 Heating board group 4a, 4b, 4c, 4d, 4e Heating board 4f, 4g, 4h, 4i, 4j Heating board 4k, 4l, 4m Heating board 5, 5a 5b, 5c Temperature measuring device 6 Air purge unit 7 Pressure regulating valve 10 Double facer 20 Corrugated cardboard sheet 111 Top part J Steam h Heat n Paste solution p Foreign substance

Claims (7)

A conveying belt with a pressure device that conveys a single-sided corrugated sheet located above and a front liner located below from above while being superposed vertically, and forms a travel path for the front liner and the one-sided A heating platen for heating and gelatinizing the paste applied to the top of the corrugated cardboard sheet, and the one-sided corrugated cardboard sheet and the front liner, which are stacked one above the other, include the conveying belt with the pressure device and the heat While being sandwiched between and transported by the board group, the paste liquid is gelatinized by heat from the front liner that is heated in contact with the hot board group, and the single-sided cardboard sheet and the A double facer in which a cardboard sheet is manufactured by laminating a front liner,
A temperature measuring device for measuring the temperature of the front liner traveling on the heating plate group, and the table measured by the temperature measuring device so that the maximum temperature of the front liner does not exceed a predetermined upper limit temperature; A double facer characterized in that the temperature of the heating plate group is controlled based on the temperature of the liner. In the double facer according to claim 1,
In the double facer, at least one of the temperature measuring devices is disposed in the vicinity of a heating plate installed on the upstream side in the heating plate group. In the double facer according to claim 1 or 2,
The double facer, wherein the temperature measuring device is a non-contact thermometer that measures the temperature of the front liner from a gap between adjacent hot plates in the hot plate group. In the double facer according to any one of claims 1 to 3,
The upper limit temperature is changed according to the basis weight of the front liner in a production order. In the double facer according to any one of claims 1 to 4,
The double facer according to claim 1, wherein the temperature of the hot platen group is controlled by adjusting a saturated vapor pressure of steam supplied to each hot platen with a pressure adjusting valve. In the double facer according to any one of claims 1 to 5,
Each of the hot plates constituting the hot plate group is made of steel, and is a double facer. In the double facer according to claim 6,
A double facer characterized in that a thickness between a heat medium supply pipe formed inside the hot plate and an upper surface of the hot plate is set to 10 mm or less.

Images