Corrugated cardboard sheet manufacturing device and method

Abstract

To suppress inhibition of detection of a spliced portion of a second sheet due to poor bonding between a core and a back liner in a manufacturing device and method for a corrugated cardboard sheet.SOLUTION: There is provided a corrugated cardboard sheet manufacturing device and method, the device comprises: a second paper-splicing device for splicing a following sheet to a preceding sheet in a second sheet; a third paper-splicing device for splicing a following sheet to a preceding sheet in a third sheet; a single-faced corrugated cardboard paper-splicing detection unit that detects a third paper splice portion of the third sheet based on a thickness of the single-faced corrugated cardboard sheet constituted by the second sheet and the third sheet being pasted together; and a control device that controls a paper splicing timing of the second paper-splicing device and / or the third paper-splicing device so that the third paper splice portion is positioned downstream in a sheet conveyance direction from a second paper splice portion of the second sheet at a pasting position of the second sheet and the third sheet.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a cardboard sheet manufacturing apparatus and method for manufacturing a cardboard sheet in which a front liner, a corrugated core, and a back liner are bonded together. [Background technology]

[0002] A corrugating machine, which is a device for manufacturing cardboard sheets, is equipped with a single facer and a double facer. The single facer processes the corrugated core and attaches a back liner to form a single-faced cardboard sheet. The double facer attaches a front liner to the single-faced cardboard sheet to form a double-faced cardboard sheet. The continuous double-faced cardboard sheet produced by the double facer is cut to a specified width by a slitter-scorer and then cut to a specified length by a cut-off device to produce cardboard sheets.

[0003] The front liner, core, and back liner are sheets supplied from rolls of paper held in their respective mill roll stands. The mill roll stand holds multiple rolls of paper, and when the current roll of paper runs low, a splicer splices sheets from a standby roll, allowing for continuous sheet unwinding. However, because spliced ​​portions of sheets are defective and cannot be used in the final product, it is desirable to detect and remove spliced ​​portions during the production of corrugated cardboard sheets. Furthermore, in a bridge that retains a predetermined length of single-faced cardboard sheets between the exit of the single facer and the entrance of the double facer, the amount of single-faced cardboard sheets retained by the bridge is calculated based on the distance traveled by the spliced ​​portions of the sheets.

[0004] Conventionally, a metal sheet such as aluminum is attached to the spliced ​​portion of a sheet, and a metal sensor detects the spliced ​​portion through the metal sheet. However, if the sheet meanders during transport, the metal sensor may not be able to detect the metal sheet, and the spliced ​​portion may end up being shipped as a product together with the metal sheet. Techniques for solving this problem include those described in Patent Documents 1 and 2 below. The corrugated cardboard sheet manufacturing devices described in Patent Documents 1 and 2 detect the position of the spliced ​​portion of a sheet based on the thickness of the corrugated cardboard sheet, and then cut and remove the spliced ​​portion. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-113895 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-105772 Summary of the Invention [Problem to be solved by the invention]

[0006] During the production of corrugated cardboard sheets, when a different type of cardboard sheet is being produced, a lot change is performed. For example, each splicer provided for a front liner, a corrugating medium, and a back liner splices a different type of front liner, a corrugating medium, and a back liner to the currently fed front liner, a corrugating medium, and a back liner. When the single facer then joins the corrugated corrugating medium and the back liner to form a single-faced cardboard sheet, it becomes difficult for the single facer to form the corrugation properly because the corrugating medium is double-layered at the splice portion, which can result in poor joining with the back liner.

[0007] A corrugating machine is provided with a bridge between the exit of the single facer and the entrance of the double facer, which retains a predetermined length of single-faced cardboard sheet. The bridge retention amount of the single-faced cardboard sheet at the bridge is calculated, for example, based on the distance the single-faced cardboard sheet travels from the detection of the back liner splice upstream of the bridge to the detection of the back liner splice downstream of the bridge. In this case, the back liner splice is detected by the difference between the thickness of the single-faced cardboard sheet at the location where the back liner splice is not present and the thickness of the single-faced cardboard sheet at the location where the back liner splice is present. However, if the splice of the corrugated fiberboard precedes the splice of the back liner and a bonding failure occurs between the corrugated fiberboard and the back liner at the splice of the corrugated fiberboard, the bonding failure will obstruct the back liner splice, preventing proper detection of the thickness of the single-faced cardboard sheet. This poses the problem that the splice portion of the back liner of a single-faced cardboard sheet cannot be detected downstream of the bridge, making it impossible to calculate the amount of bridge retention.

[0008] The present disclosure aims to solve the above-mentioned problems and to provide a cardboard sheet manufacturing device and method that suppresses interference with detection of the splice portion of the second sheet due to poor bonding between the core and the back liner. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the cardboard sheet manufacturing device of the present disclosure is a cardboard sheet manufacturing device that conveys a cardboard sheet in which a first sheet, a corrugated second sheet, and a third sheet are bonded together, and is equipped with a second splicing device that splices a subsequent sheet to a preceding sheet in the second sheet, a third splicing device that splices a subsequent sheet to a preceding sheet in the third sheet, a single-sided cardboard splicing detection unit that detects the third splice portion of the third sheet based on the thickness of the single-sided cardboard sheet in which the second sheet and the third sheet are bonded together, and a control device that controls the splicing timing of at least one of the second splicing device and the third splicing device so that the third splice portion is located downstream in the sheet conveying direction from the second splice portion of the second sheet at the bonding position of the second sheet and the third sheet.

[0010] In addition, the method for manufacturing a cardboard sheet disclosed herein is a method for manufacturing a cardboard sheet in which a first sheet, a corrugated second sheet, and a third sheet are bonded together, and the method includes the steps of: splicing a subsequent sheet to a preceding sheet in the second sheet; splicing a subsequent sheet to a preceding sheet in the third sheet; controlling the splicing timing of at least one of the second sheet and the third sheet so that the third splice portion of the third sheet is located downstream in the sheet conveying direction from the second splice portion of the second sheet at the bonding position of the second sheet and the third sheet; and detecting the third splice portion based on the thickness of the single-faced cardboard sheet in which the second sheet and the third sheet are bonded together. [Effects of the Invention]

[0011] According to the cardboard sheet manufacturing device and method of the present disclosure, it is possible to suppress the detection of the spliced ​​portion of the second sheet being hindered by poor lamination between the core and the back liner. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing the corrugating machine of this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of the cardboard sheet manufacturing device of this embodiment. [Figure 3] FIG. 3 is a schematic diagram showing the process flow in the cardboard sheet manufacturing device of this embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a method for splicing sheets. [Figure 5] FIG. 5 is a schematic diagram showing the sheet splicing detection unit. [Figure 6] FIG. 6 is a schematic diagram showing the single-faced corrugated cardboard splice detection unit. [Figure 7] FIG. 7 is a schematic diagram showing a step deformation device. [Figure 8] FIG. 8 is a schematic diagram of the periphery of the single facer to explain the flow of the core, back liner and single-faced cardboard sheets. [Figure 9] FIG. 9 is a schematic diagram of the area around the double facer to explain the flow of the front liner and single-faced cardboard sheets. [Figure 10] FIG. 10 is a schematic diagram showing a single-faced corrugated cardboard sheet. [Figure 11] FIG. 11 is a schematic diagram showing a splice portion of a single-faced corrugated cardboard sheet. [Figure 12] FIG. 12 is a schematic diagram showing a defect at a splice portion of a single-faced corrugated cardboard sheet. [Figure 13] FIG. 13 is a schematic diagram showing a corrugation deformation portion of a single-faced corrugated cardboard sheet. [Figure 14] FIG. 14 is a flowchart showing a method for manufacturing a cardboard sheet. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0014] [Present embodiment] <Outline of the corrugating machine> The cardboard sheet manufacturing device of this embodiment is applied to a corrugating machine. Fig. 1 is a schematic diagram showing the corrugating machine. In the following description, the longitudinal direction of the corrugating machine is defined as the X direction, the horizontal direction perpendicular to the longitudinal direction (X direction) of the corrugating machine is defined as the Y direction (width direction of the cardboard sheet), and the vertical direction perpendicular to the longitudinal direction (X direction) of the corrugating machine (thickness direction of the cardboard sheet) is defined as the Z direction. The first sheet corresponds to the front liner A, the second sheet corresponds to the cores B1 and B2, and the third sheet corresponds to the back liners C1 and C2.

[0015] As shown in Figure 1, the corrugating machine 10 first laminates a back liner C1 onto a corrugated corrugation medium B1 to produce a single-faced cardboard sheet D1, and then laminates a back liner C2 onto a corrugated corrugation medium B2 to produce a single-faced cardboard sheet D2. Next, the back liner C2 of a single-faced cardboard sheet D2 is laminated onto the medium B1 of the produced single-faced cardboard sheet D1, and a front liner A is laminated onto the medium B2 of the single-faced cardboard sheet D2 to produce a continuous double-faced cardboard sheet. The continuous double-faced cardboard sheet is then cut to a predetermined length to produce a plate-shaped double-faced cardboard sheet.

[0016] The corrugating machine 10 can also produce double-faced corrugated cardboard sheets by laminating a single-faced corrugated cardboard sheet D2 or a single-faced corrugated cardboard sheet D1 with a front liner A. The corrugating machine 10 can also produce double-faced corrugated cardboard sheets by laminating a single-faced corrugated cardboard sheet D1, a single-faced corrugated cardboard sheet D2, and a front liner A. Therefore, in the following explanation, double-faced corrugated cardboard sheets and double-faced corrugated cardboard sheets will be collectively referred to as double-faced corrugated cardboard sheets E. Furthermore, plate-shaped double-faced corrugated cardboard sheets and plate-shaped double-faced corrugated cardboard sheets will be collectively referred to as double-faced corrugated cardboard sheets F.

[0017] The corrugating machine 10 includes a mill roll stand 11 for the core B1, a mill roll stand 12 for the back liner C1, a single facer 13, a bridge 14, a mill roll stand 15 for the core B2, a mill roll stand 16 for the back liner C2, a single facer 17, a bridge 18, a mill roll stand 19 for the front liner A, a preheater 20, a glue machine 21, a double facer 22, a rotary shear 23, a slitter scorer 24, a cutoff 25, a defective product ejection device 26, and a stacker 27.

[0018] Roll paper with cores B1 and B2 wound in roll form is mounted on each side of the mill roll stands 11 and 15 in the X direction, and splicers (second paper splicing devices) 31 and 32 are provided between each roll paper. While one roll paper is being fed, the other roll paper is loaded and preparation for splicing begins. When one roll paper is running low, the splicers 31 and 32 splice the other roll paper onto the first roll paper. Therefore, cores B1 and B2 are continuously fed downstream from each mill roll stand 11 and 15.

[0019] Roll paper with back liners C1 and C2 wound in roll form is mounted on both sides of the mill roll stands 12 and 16 in the X direction, and splicers (third paper splicing devices) 33 and 34 are provided between each roll paper. When one roll paper is being fed, the other roll paper is loaded and preparation for splicing begins. When one roll paper is running low, the splicers 33 and 34 splice the other roll paper onto the first roll paper. Therefore, back liners C1 and C2 are continuously fed downstream from each mill roll stand 12 and 16.

[0020] The cores B1 and B2 delivered from the mill roll stands 11 and 15 and the back liners C1 and C2 delivered from the mill roll stands 12 and 16 are preheated by preheaters (not shown). Each preheater has a heating roll to which steam is supplied, and the cores B1 and B2 and the back liners C1 and C2 are heated to a predetermined temperature by being wound around the heating roll and transported.

[0021] The single facer 13 processes the heated corrugation medium B1 into a corrugated shape, then glues it to the top of each flute and attaches a heated back liner C1 to form a single-faced cardboard sheet D1. A pick-up conveyor 28 is provided at the outlet of the single-faced cardboard sheet D1 of the single facer 13, and transports the single-faced cardboard sheet D1 formed by the single facer 13 to the bridge 14. The bridge 14 temporarily retains the single-faced cardboard sheet D1 to absorb the speed difference between the single facer 13 and the double facer 22.

[0022] The single facer 17 processes the heated corrugation medium B2 into a corrugated shape, then glues it to the top of each flute and attaches a heated back liner C2 to form a single-faced cardboard sheet D2. A pick-up conveyor 29 is provided at the outlet of the single-faced cardboard sheet D2 of the single facer 17, and transports the single-faced cardboard sheet D2 formed by the single facer 17 to the bridge 18. The bridge 18 temporarily retains the single-faced cardboard sheet D2 to absorb the speed difference between the single facer 17 and the double facer 22.

[0023] In addition, the paper guide device 30 is provided at the exit portion of the bridge 14 and the bridge 18. The paper guide device 30 adjusts the Y-direction position of the single-faced cardboard sheets D1 and D2 between the bridge 14 and the bridge 18 and the double facer 22.

[0024] Rolls of paper with front liner A wound in roll form are mounted on both sides of the mill roll stand 19 in the X direction, and a splicer (first paper splicing device) 35 is provided between each roll of paper. While one roll of paper is being fed, the other roll of paper is loaded and preparation for splicing is made, and when one roll of paper is running low, the splicer splices the other roll of paper onto the first roll of paper. For this reason, front liner A is continuously fed downstream from the mill roll stand 19.

[0025] The preheater 20 has three preheating rolls 41, 42, and 43 arranged side by side in the Z direction. The preheating roll 41 heats the front liner A, the preheating roll 42 heats the single-faced cardboard sheet D2, and the preheating roll 43 heats the single-faced cardboard sheet D1. Each of the preheating rolls 41, 42, and 43 has a winding amount adjustment device (not shown), and is heated to a predetermined temperature by supplying steam therein. The front liner A, the single-faced cardboard sheet D2, and the single-faced cardboard sheet D1 are wrapped around the peripheral surface, thereby preheating the rolls.

[0026] The glue machine 21 has gluing rolls 44 and 45 arranged side by side in the Z direction. The glue roll 44 contacts and glues each top of the corrugations of the medium B2 in the single-faced cardboard sheet D2 heated by the preheating roll 42. The glue roll 45 contacts and glues each top of the corrugations of the medium B1 in the single-faced cardboard sheet D1 heated by the preheating roll 43. The single-faced cardboard sheets D1 and D2 glued by the glue machine 21 are transferred to the double facer 22 in the next process. The front liner A heated by the preheating roll 41 is also transferred to the double facer 22 through the glue machine 21.

[0027] The double facer 22 has an upstream heating section 36 and a downstream cooling section 37 along the travel line of the single-faced cardboard sheets D1, D2 and the front liner A. The single-faced cardboard sheets D1, D2 and the front liner A, which have been glued by the glue machine 21, are transported between the pressure belt and the hot plate in the heating section 36, and are transported together in an overlapping state toward the cooling section 37. During this transport, the single-faced cardboard sheets D1, D2 and the front liner A are heated and pressurized, so that they are bonded together to form a continuous double-faced cardboard sheet E, which is then naturally cooled while being transported.

[0028] The double-sided corrugated cardboard sheet E produced by the double facer 22 is transferred to the slitter scorer 24. The slitter scorer 24 cuts the wide double-sided corrugated cardboard sheet E along the X direction to a predetermined width, and processes creases extending in the X direction. The slitter scorer 24 is made up of a first slitter scorer unit 53 and a second slitter scorer unit 54, which have substantially the same structure and are arranged along the X direction of the double-sided corrugated cardboard sheet E. The wide double-sided corrugated cardboard sheet E is cut by the slitter scorer 24 to form a double-sided corrugated cardboard sheet E of a predetermined width.

[0029] The cutoff 25 cuts the double-sided cardboard sheet E cut in the X direction by the slitter scorer 24 along the Y direction to form plate-shaped double-sided cardboard sheets F of a predetermined length. The defective product ejection device 26 ejects double-sided cardboard sheets F determined to be defective by a defect detection device (described later) from the conveying line. The defective product ejection device 26 has a discharge conveyor and a sorting roll (not shown). When a plate-shaped double-sided cardboard sheet F determined to be defective is conveyed, the sorting roll descends to sort the defective plate-shaped double-sided cardboard sheet F onto the discharge conveyor and eject it. The stacker 27 stacks double-sided cardboard sheets F determined to be non-defective and ejects them outside the machine as products.

[0030] <Detailed configuration of the corrugating machine> The configuration of the cardboard sheet manufacturing apparatus of this embodiment will be described below. Fig. 2 is a schematic diagram showing the configuration of the cardboard sheet manufacturing apparatus of this embodiment, and Fig. 3 is a schematic diagram showing the processing flow in the cardboard sheet manufacturing apparatus of this embodiment.

[0031] The corrugating machine 10 conveys the front liner A, the corrugated cores B1, B2, and the back liners C1, C2 individually, and forms single-faced cardboard sheets D1, D2 by bonding the corrugated cores B1, B2 to the back liners C1, C2, and also forms double-faced cardboard sheets E by bonding the front liner A to the single-faced cardboard sheets D1, D2.

[0032] As shown in FIG. 2, the corrugating machine 10 includes a sheet splicing detection unit 61, a single-face corrugated cardboard splicing detection unit 62, a corrugation deformation device 63, and a control device 64.

[0033] The sheet splicing detection unit 61 is disposed between the sheet splicing position and the sheet bonding position in the sheet conveying direction (one side of the X direction). Here, the sheet splicing position is the position where the leading sheet and the trailing sheet are connected by the front liner A, the mediums B1 and B2, and the back liners C1 and C2. The sheet bonding position is the position where the corrugated mediums B1 and B2 and the back liners C1 and C2 are bonded together, or the position where the front liner A and the single-faced corrugated sheets D1 and D2 are bonded together. The sheet splicing detection unit 61 detects the spliced ​​portion based on the sheet shape. Specifically, the sheet splicing detection unit 61 detects the spliced ​​portion based on the sheet thicknesses of the front liner A, the mediums B1 and B2, and the back liners C1 and C2.

[0034] The single-faced corrugated cardboard splice detection unit 62 is disposed between the sheet retention position and the sheet bonding position in the sheet conveyance direction. Here, the sheet retention position is the position where the single-faced corrugated cardboard sheets D1 and D2 are retained, and the sheet bonding position is the position where the front liner A and the single-faced corrugated cardboard sheets D1 and D2 are bonded together. The single-faced corrugated cardboard splice detection unit 62 detects the splice portion based on the sheet shape. Specifically, the single-faced corrugated cardboard splice detection unit 62 detects the splice portion based on the sheet thickness of the single-faced corrugated cardboard sheets D1 and D2.

[0035] The corrugation deformation device 63 is disposed between the sheet bonding position and the sheet retention position in the sheet conveying direction. Here, the sheet bonding position is the position where the corrugated corrugations B1, B2 and the back liners C1, C2 are bonded together, and the sheet retention position is the position where the single-faced cardboard sheets D1, D2 are retained. The corrugation deformation device 63 forms corrugation-deformed portions by deforming the corrugations formed by corrugating the corrugations B1, B2. Specifically, the corrugation deformation device 63 crushes and deforms the corrugations of the corrugations of the corrugations B1, B2 that make up the single-faced cardboard sheets D1, D2 to form the corrugation-deformed portions.

[0036] The single-faced corrugated cardboard splicing detection unit 62 detects corrugation deformation portions in the single-faced corrugated cardboard sheets D1, D2 formed by the corrugation deformation device 63. The single-faced corrugated cardboard splicing detection unit 62 also detects corrugation deformation portions (defective portions) in the single-faced corrugated cardboard sheets D1, D2 other than those formed by the corrugation deformation device 63.

[0037] The control device 64 controls the splicing timing of at least one of the splicers 31, 32 and the splicers 33, 34 so that the splice portion (third splice portion) of the back liners C1, C2 is located downstream in the sheet conveying direction from the splice portion (second splice portion) of the corrugated corrugations B1, B2 at the joining position of the corrugated corrugations B1, B2 and the back liners C1, C2. The control device 64 also controls the operation timing of the defective product ejection device 26 based on positional information of the splice portion and the corrugation deformation portion detected by the sheet splice detection unit 61 and the single-faced corrugated board splice detection unit 62. Here, the control device 64 is a controller, and is realized by, for example, a CPU (Central Processing Unit) or MPU (Micro Processing Unit) executing various programs stored in a memory unit using RAM as a work area.

[0038] The process flow in the corrugating machine 10 will be described. As shown in Figures 2 and 3, the sheet splice detection unit 61 detects the spliced ​​portions of the front liner A, the corrugating medium B1, B2, and the back liners C1, C2. The corrugating medium B1, B2 are paid out from the mill roll stands 11, 15, and are transported to the single facers 13, 17 through the splicers 31, 32. The back liners C1, C2 are paid out from the mill roll stands 12, 16, and are transported to the single facers 13, 17 through the splicers 33, 34. The front liner A is paid out from the mill roll stand 19, and is transported to the preheater 20 through the splicer 35.

[0039] The sheet splicing detection unit 61 is composed of five ultrasonic sensors 61a, 61b, 61c, 61d, and 61e. The ultrasonic sensors 61a and 61c are arranged between the splicers 31 and 33 and the single facer 13. The ultrasonic sensors 61b and 61d are arranged between the splicers 32 and 34 and the single facer 17. The ultrasonic sensor 61e is arranged between the splicer 35 and the preheater 20. The ultrasonic sensors 61a, 61b, 61c, 61d, and 61e are connected to the control device 64 and output the detection results to the control device 64.

[0040] The single-faced corrugated cardboard splice detection unit 62 detects splice portions and corrugation deformation portions based on the sheet thickness of the single-faced corrugated cardboard sheets D1 and D2. The single-faced corrugated cardboard sheet D1 is transported from the single facer 13 to the double facer 22 via the bridge 14, preheater 20, and glue machine 21. The single-faced corrugated cardboard sheet D2 is transported from the single facer 17 to the double facer 22 via the bridge 18, preheater 20, and glue machine 21.

[0041] The single-faced corrugated cardboard splicing detection unit 62 is composed of two laser displacement meters 62a and 62b. The laser displacement meters 62a and 62b are placed between the preheater 20 and the glue machine 21. The laser displacement meters 62a and 62b are placed a predetermined distance away from the surfaces of the cores B1 and B2 of the single-faced corrugated cardboard sheets D1 and D2 to which the front liner A is attached. The laser displacement meters 62a and 62b are connected to a control device 64 and output detection results to the control device 64.

[0042] The corrugation deformation device 63 is connected to a control device 64, which controls the operation of the corrugation deformation device 63. The control device 64 operates the corrugation deformation device 63 to deform the corrugations of the corrugations of the mediums B1 and B2 in the single-faced corrugated cardboard sheets D1 and D2, thereby forming a corrugation deformation portion. The corrugation deformation device 63 is composed of two crushing devices 63a and 63b. The crushing devices 63a and 63b are arranged between the single facers 13 and 17 and the bridges 14 and 18.

[0043] The crushing device 63a is movably disposed at a position a predetermined distance away from the back liner C1 that constitutes the single-faced cardboard sheet D1. The crushing device 63a moves toward the single-faced cardboard sheet D1 and crushes the corrugated core B1 in the single-faced cardboard sheet D1 to form a corrugated deformation portion. The crushing device 63b is movably disposed at a position a predetermined distance away from the back liner C2 that constitutes the single-faced cardboard sheet D2. The crushing device 63b moves toward the single-faced cardboard sheet D2 and crushes the corrugated core B2 in the single-faced cardboard sheet D2 to form a corrugated deformation portion.

[0044] When changing lots to change the type of cardboard sheet being manufactured (width, thickness, paper quality, etc.), the control device 64 controls the splicing timing of the splicers 31, 32, 33, 34, 35. At this time, the control device 64 adjusts the splicing timing of the splicers 31, 32 and the splicers 33, 34 so that at the bonding position of the cores B1, B2 and the back liners C1, C2 in the single facers 13, 17, the splicing portions of the back liners C1, C2 precede the splicing portions of the cores B1, B2 and are positioned downstream in the sheet conveying direction.

[0045] In addition, when splicing due to a lot change or a shortage of roll paper, the control device 64 calculates the bridge retention amount of single-sided cardboard sheets D1, D2 at bridges 14, 18 based on the position of the splice portion of the back liners C1, C2 detected by the sheet splice detection unit 61 and the position of the splice portion of the back liners C1, C2 in the single-sided cardboard sheets D1, D2 detected by the single-sided cardboard splice detection unit 62.

[0046] Furthermore, the control device 64 operates the corrugation deformation device 63 to form corrugation deformation portions in the single-faced cardboard sheets D1, D2 when the corrugating machine 10 starts operating. Then, the control device 64 calculates the bridge retention amount of the single-faced cardboard sheets D1, D2 at the bridges 14, 18 based on the positions of the corrugation deformation portions in the single-faced cardboard sheets D1, D2 formed by the corrugation deformation device 63 and the positions of the corrugation deformation portions in the single-faced cardboard sheets D1, D2 detected by the single-faced cardboard splice detection unit 62.

[0047] Furthermore, the control device 64 tracks the spliced ​​portions in the front liner A, the corrugation medium B1, B2, and the back liners C1, C2 detected by the sheet splice detection unit 61, and the corrugated deformation portions detected by the single-faced corrugated board splice detection unit 62. The control device 64 controls the operation timing of the defective product ejection device 26 based on the positional information of the spliced ​​portions and the corrugated deformation portions.

[0048] <Sheet splicing detection unit> FIG. 4 is a schematic diagram showing a sheet splicing method, and FIG. 5 is a schematic diagram showing a sheet splicing detection unit.

[0049] As shown in Figures 3 and 4, the mill roll stand 11 unwinds the medium B1 as one of the paper rolls rotates. If one of the paper rolls runs low or a change in lot is required, the splicer 31 splices the medium B1. That is, while one of the paper rolls rotates to unwind the leading sheet B1a of the medium B1, the splicer 31 rotates the other paper roll at the same speed to unwind the trailing sheet B1b of the medium B1 and splice the leading sheet B1a to the trailing sheet B1b. This allows the mill roll stand 11 to continuously unwind the medium B1.

[0050] The splicing of the medium B1 will be described in detail. The leading sheet B1a of the medium B1 travels along the sheet conveying direction X1, and the trailing sheet B1b travels along the sheet conveying direction X2 at the same speed. At this time, the trailing sheet B1b has double-sided tape Tb attached as an adhesive to the side of the cut leading edge facing the leading sheet B1a. At a predetermined time, the leading sheet B1a and the trailing sheet B1b are pressed together with the double-sided tape Tb sandwiched between them. Then, the double-sided tape Tb of the trailing sheet B1b is pressed against the attached portion B1T of the leading sheet B1a, and the trailing sheet B1b is joined to the leading sheet B1a. Simultaneously with this operation, the leading sheet B1a is cut upstream of the splice portion with the trailing sheet B1b.

[0051] As shown in Figure 5, the core B1 has a spliced ​​portion B1c formed by connecting the rear end of the preceding sheet B1a to the front end of the following sheet B1b with double-sided tape Tb. The spliced ​​portion B1c is formed by connecting the lower surface of the rear end of the preceding sheet B1a to the upper surface of the front end of the following sheet B1b so that they overlap with each other with double-sided tape Tb. Therefore, the thickness of the spliced ​​portion B1c is the sum of the thicknesses of the preceding sheet B1a, the following sheet B1b, and the double-sided tape Tb. In other words, the thickness of the spliced ​​portion B1c is thicker than the thicknesses of the preceding sheet B1a and the following sheet B1b.

[0052] The sheet splicing detection unit 61 has an ultrasonic sensor 61a. The ultrasonic sensor 61a has a transmitter 61a-1 and a receiver 61a-2. The transmitter 61a-1 is located on the upper surface of the medium B1 being transported, and the receiver 61a-2 is located on the lower surface of the medium B1 being transported. The transmitter 61a-1 and receiver 61a-2 are located so as to face each other vertically.

[0053] The transmitter 61a-1 transmits ultrasonic waves toward the corrugated medium B1, and the receiver 61a-2 receives the ultrasonic waves that have passed through the corrugated medium B1. The ultrasonic waves transmitted from the transmitter 61a-1 are attenuated as they pass through the corrugated medium B1, and the receiver 61a-2 receives the attenuated ultrasonic waves. The thickness of the spliced ​​portion B1c of the corrugated medium B1 is greater than that of the preceding sheet B1a or the following sheet B1b. Therefore, the attenuation of ultrasonic waves at the spliced ​​portion B1c of the corrugated medium B1 is greater than that of the preceding sheet B1a or the following sheet B1b. The ultrasonic sensor 61a outputs the level of the ultrasonic waves received by the receiver 61a-2 to the control device 64. The control device 64 detects the spliced ​​portion B1c based on the level of the ultrasonic waves input from the ultrasonic sensor 61a.

[0054] That is, the level of ultrasonic waves transmitted through the preceding sheet B1a and the following sheet B1b is measured in advance, and the level of ultrasonic waves transmitted through the spliced ​​portion B1c is also measured. A threshold value is set between the level of ultrasonic waves transmitted through the preceding sheet B1a and the following sheet B1b and the level of ultrasonic waves transmitted through the spliced ​​portion B1c. The control device 64 then detects the spliced ​​portion B1c by comparing the level of ultrasonic waves input from the ultrasonic sensor 61a with the threshold value. That is, when the level of ultrasonic waves input from the ultrasonic sensor 61a exceeds the threshold value, the control device 64 determines that the spliced ​​portion B1c is present.

[0055] Up to this point, the ultrasonic sensor 61a has been described as detecting the spliced ​​portion B1c of the medium B1, but the same applies to the spliced ​​portions of the front liner A, medium B2, and back liners C1 and C2, and the ultrasonic sensors 61b, 61c, 61d, and 61e.

[0056] Furthermore, the sheet splice detection unit 61 is not limited to being configured as an ultrasonic sensor 61a. For example, the sheet splice detection unit 61 may be configured as a laser displacement meter. That is, the laser displacement meter is disposed on the upper or lower surface side of the transported core B1. The splice portion B1c has a step between the preceding sheet B1a and the following sheet B1b. Therefore, the distance from the laser displacement meter to the preceding sheet B1a is different from the distance from the laser displacement meter to the following sheet B1b. The control device 64 detects the sheet step by comparing the time it takes for the laser displacement meter to transmit light toward the preceding sheet B1a, reflect, and return with the time it takes for the laser displacement meter to transmit light toward the following sheet B1b, reflect, and return, and detects the splice portion B1c based on the position of the sheet step.

[0057] <Single-sided corrugated cardboard splice detection unit> FIG. 6 is a schematic diagram showing the single-faced corrugated cardboard splice detection unit.

[0058] As shown in Figure 6, the single-faced cardboard sheet D1 is constructed by attaching a sheet-shaped back liner C1 to a corrugated core B1. The single-faced cardboard sheet D1 is wound at a predetermined angle around a guide roll 184c (described later) and conveyed. At this time, the single-faced cardboard sheet D1 is guided so that the back liner C1 contacts the guide roll 184c and the corrugated core B1 is positioned on the outside.

[0059] The single-faced corrugated cardboard splice detection unit 62 has a laser displacement meter 62a. The laser displacement meter 62a has an irradiator 62a-1 and a light-receiving unit 62a-2. The irradiator 62a-1 irradiates, for example, a laser beam of a predetermined width. The irradiator 62a-1 irradiates the laser beam in the tangential direction of the single-faced corrugated cardboard sheet D1 wound around the guide roll 184c. At this time, the irradiator 62a-1 irradiates the laser beam toward the corrugated medium B1 in the single-faced corrugated cardboard sheet D1. The light-receiving unit 62a-2 receives the laser beam irradiated by the irradiator 62a-1. The light-receiving unit 62a-2 is positioned opposite the target of the laser beam irradiated from the irradiator 62a-1. The light-receiving unit 62a-2 receives the laser beam irradiated from the irradiator 62a-1 that is not blocked by the medium B1 in the single-faced corrugated cardboard sheet D1.

[0060] The single-faced cardboard sheet D1 is guided by the guide roll 184c and conveyed. The irradiator 62a-1 irradiates a laser beam toward the corrugated medium B1 of the single-faced cardboard sheet D1 guided by the guide roll 184c. At this time, if the corrugated ridges of the corrugated medium B1 of the single-faced cardboard sheet D1 are not crushed or deformed, the laser beam is blocked by the corrugated ridges of the corrugated medium B1. The light-receiving unit 62a-2 then receives the laser beam whose width has been reduced due to being blocked by the corrugated ridges of the corrugated medium B1. On the other hand, if the corrugated ridges of the corrugated medium B1 of the single-faced cardboard sheet D1 are crushed and deformed, the amount of the laser beam blocked by the corrugated ridges (deformed corrugated portions) of the corrugated medium B1 is reduced. The light-receiving unit 62a-2 then receives the laser beam whose width is not blocked by the corrugated ridges of the corrugated medium B1 and whose width is hardly reduced. The control device 64 detects the spliced ​​portion and the deformed corrugated portion based on the width of the laser beam input from the laser displacement meter 62a.

[0061] That is, the width of the laser beam is measured in advance on a single-faced cardboard sheet D1 on which a normal corrugation is formed at a position other than the splice portion. A judgment value (judgment area) is set based on the measured width of the laser beam. The control device 64 then detects the splice portion and the corrugation deformation portion by comparing the width of the laser beam input from the laser displacement meter 62a with the judgment value. That is, the control device 64 judges the single-faced cardboard sheet D1 to be a non-defective product if the width of the laser beam input from the laser displacement meter 62a is within the judgment value range. Then, the control device 64 judges the single-faced cardboard sheet D1 to be a non-defective product if the width of the laser beam input from the laser displacement meter 62a exceeds the judgment value, determining that the corrugation is deformed, that is, the single-faced cardboard sheet D1 is a defective product with a corrugation deformation portion. On the other hand, the control device 64 judges the single-faced cardboard sheet D1 to be a defective product with a splice portion if the width of the laser beam input from the laser displacement meter 62a is equal to or less than the judgment value. Note that the width of the laser beam may be measured in advance on a single-faced cardboard sheet D1 on which a normal corrugation is formed at the splice portion, and a judgment value for the splice portion may be set.

[0062] Up to this point, we have explained the laser displacement meter 62a, which detects the splice and corrugated deformation portions of the single-faced cardboard sheet D1, but the same applies to the laser displacement meter 62b, which detects the splice and corrugated deformation portions of the single-faced cardboard sheet D2.

[0063] <Step transformation device> FIG. 7 is a schematic diagram showing a step deformation device.

[0064] As shown by the solid line in Figure 7, the corrugation deformation device 63 is disposed downstream in the sheet conveying direction of the take-up conveyor 28. The take-up conveyor 28 has a first lower belt 172, a second lower belt 173, and an upper belt 174. The corrugation deformation device 63 crushes and deforms the corrugated medium B1 in the single-faced cardboard sheet D1 conveyed by each of the belts 172, 173, 174, to form a corrugation deformation portion.

[0065] The corrugation deformation device 63 has a crushing device 63a. The crushing device 63a has a rotating link 81, a crushing roller 82, and a drive device 83. The rotating link 81 is rotatably supported on a frame (not shown) by an attachment member 84. The crushing roller 82 is rotatably supported on the lower part of the rotating link 81 by a support member 85. The drive device 83 is attached to the frame (not shown), and the tip of the drive rod 83a is connected to the upper part of the rotating link 81 by a connecting member 86. The drive device 83 is a fluid pressure cylinder such as an air cylinder or a hydraulic cylinder, but may also be a drive motor. The crushing roller 82 is disposed above the guide roll that supports the second lower belt 173 with a predetermined gap therebetween. The predetermined gap is a gap that allows the single-faced cardboard sheet D1 supported by the guide roll to be conveyed without coming into contact with the crushing roller 82.

[0066] Therefore, the single-faced cardboard sheet D1 is transported by the take-up conveyor 28. The control device 64 activates the crushing device 63a at a predetermined timing. When the drive device 83 is activated, the crushing device 63a extends the drive rod 83a and rotates the rotating link 81 clockwise in FIG. 7. As a result, the crushing roller 82 moves closer to the single-faced cardboard sheet D1 guided by the second lower belt 173, crushing the corrugations of the medium B1 in the single-faced cardboard sheet D1 to form a corrugation deformation portion. The laser displacement meter 62a of the single-faced cardboard splice detection unit 62 detects the corrugation deformation portion formed by the crushing device 63a.

[0067] 7, the crushing device 63a may be disposed upstream in the conveying direction of the take-up conveyor 28. The crushing roller 82 is disposed above the guide roll that supports the first lower belt 172 with a predetermined gap therebetween. The predetermined gap is a gap that allows the single-faced cardboard sheet D1 supported by the guide roll to be conveyed without coming into contact with the crushing roller 82. The crushing device 63a crushes and deforms the corrugated core B1 in the single-faced cardboard sheet D1 conveyed by each belt 172, 173, 174, forming a corrugated deformation portion.

[0068] Furthermore, the crushing roller 82 is provided as the crushing device 63a, but the crushing roller 82 may be a drivable roller or a rotating roller that can rotate together. Furthermore, it is not limited to the crushing roller 82, but may be a crushing block or a crushing plate, and is not limited to these shapes. Furthermore, the crushing roller 82 is supported rotatably by the rotating link 81, but it may also be slidable.

[0069] Although the crushing device 63a for single-faced corrugated cardboard sheets D1 has been described so far, the same applies to the crushing device 63b for single-faced corrugated cardboard sheets D2.

[0070] <Single Facer> 8 is a schematic diagram of the peripheral area of ​​the single facer to explain the flow of the corrugation medium, back liner, and single-faced cardboard sheet. Note that since single facer 13 and single facer 17 have almost the same configuration, the configuration of the peripheral area of ​​single facer 13 will be explained, and the configuration of the peripheral area of ​​single facer 17 will not be explained.

[0071] As shown in FIG. 8, the mill roll stand 11 has a stand 101 installed in a predetermined position, and roll support arms 102a and 102b on either side in the X direction. Rolls of paper R1 and R2 with a core B1 are rotatably supported at the tips of the roll support arms 102a and 102b. The rolls of paper R1 and R2 are rolls of a predetermined length of core B1 wound up in a roll shape. In the mill roll stand 11, for example, the roll of paper R1 supported by one roll support arm 102a rotates to supply the core B1, while the roll of paper R2 supported by the other roll support arm 102b stops and waits for the core B1 to be spliced.

[0072] The splicer 31 is disposed above the mill roll stand 11 in the Z direction. The splicer 31 is configured by arranging a pair of introduction rolls 104a, 104b, a pair of knives 105a, 105b, and a pair of crimping bars 106a, 106b above the header 103 in the Z direction. In the splicer 31, a nip roll 107 and an acceleration roll 108 are disposed facing each other above the crimping bars 106a, 106b in the Z direction. The introduction rolls 104a, 104b, the knives 105a, 105b, and the crimping bars 106a, 106b are disposed so as to be able to move toward and away from each other in the X direction. The nip roll 107 is disposed so as to be able to move toward and away from the acceleration roll 108 in the X direction. In the header 103, a dancer roll 109 and a fixed roll 110 are disposed above the nip roll 107 and the acceleration roll 108 in the Z direction. Although not shown, multiple dancer rolls 109 (for example, three) are provided and are movable horizontally according to the tension of the core B1. That is, the dancer rolls 109 are movable between the position shown in FIG. 8 and a position close to the fixed roll 110.

[0073] Therefore, when the core B1 is unwound from the paper roll R1, the core B1 passes between the introduction rolls 104a and 104b, between the knives 105a and 105b and between the pressure bars 106a and 106b, and is transported from the acceleration roll 108 to the dancer roll 109 and then to the fixed roll 110. When splicing is performed by the splicer 31, the unwound core B1 from the paper roll R1 is stopped, and the core B1 from the waiting paper roll R2 is attached to the core B1 of the paper roll R1 to perform the splicing, and then the paper roll R2 is rotated to unwound the core B1.

[0074] That is, the core B1 is unwound from the paper roll R2 and attached to the pressure bar 106b. The unwound speed of the core B1 from the paper roll R1 is reduced, and the dancer roll 109 moves toward the fixed roll 110, starting to consume the retained core B1. At this point, the unwound core B1 from the paper roll R1 is stopped, and the pressure bars 106a and 106b are moved closer together, so that the core B1 from the paper roll R2 is pressed against the core B1 from the paper roll R1, and they are pressed together with adhesive (double-sided tape). At the same time as this operation, the knife 105a moves forward and cuts the core B1 from the paper roll R1.

[0075] During this paper splicing, the dancer roll 109 moves to maintain a constant tension on the medium B1 and continue to release the retained medium B1. When the medium B1 from the roll paper R1 is cut and the medium B1 is unwound from the roll paper R2, the nip roll 107 comes into contact with the acceleration roll 108, increasing the rotational speed of the acceleration roll 108, thereby completing the release of the retained medium B1, and the dancer roll 109 begins to move and return to its original position.

[0076] The mill roll stand 12 (see FIG. 1) that pays out the back liner C1 and the splicer 33 that splices the back liner C1 are also substantially similar to the mill roll stand 11 and the splicer 31.

[0077] The single facer 13 includes a belt roll 121 , a tension roll 122 , a pressure belt 123 , an upper roll 124 , a lower roll 125 , and a gluing device 126 .

[0078] The belt roll 121 can be driven to rotate by a driving device (not shown). The tension roll 122 is rotatably supported at a predetermined distance from the belt roll 121. The pressure belt 123 is an endless belt that is wound around the belt roll 121 and the tension roll 122. The upper roll 124 can be driven to rotate by a driving device (not shown), and has a corrugated outer circumferential surface. The upper roll 124 is disposed below the pressure belt 123 in the Z direction between the belt roll 121 and the tension roll 122, and its corrugated outer circumferential surface abuts against the lower surface of the pressure belt 123 in a pressed state. The lower roll 125, like the upper roll 124, has a corrugated outer circumferential surface and meshes with the outer circumferential surface of the upper roll 124 below the upper roll 124 in the Z direction. The belt roll 121, tension roll 122, upper roll 124, and lower roll 125 are heated by steam circulating inside them. Core B1 and Back liner C1 is heated via a pressure belt 123 and an upper roll 124.

[0079] The gluing device 126 is disposed near the upper roll 124 in the X direction. The gluing device 126 includes a glue dam 127, a gluing roll 128, a meter roll 129, and a glue scraper blade 130. The glue dam 127 stores a predetermined amount of glue. The glue roll 128 adheres the glue stored in the glue dam 127 to the medium B1 transported by the upper roll 124, thereby gluing the medium B1. The meter roll 129 contacts the outer peripheral surface of the gluing roll 128 and rotates in synchronization with the glue roll 128, thereby adjusting the amount of glue adhered to the outer peripheral surface of the gluing roll 128. The glue scraper blade 130 contacts the outer peripheral surface of the meter roll 129, thereby scraping off excess glue removed from the gluing roll 128 and adhering to the outer peripheral surface of the meter roll 129.

[0080] The single facer 13 is provided with a preheating roll 131 and an angle adjusting roll 132 that introduce the medium B1 supplied from the splicer 31 between the upper roll 124 and the lower roll 125. The angle adjusting roll 132 moves around the preheating roll 131 to adjust the contact position where the medium B1 comes into contact with the outer circumferential surface of the preheating roll 131. The single facer 13 is also provided with a preheating roll 133 and a fixing roll 134 that introduce the back liner C1 supplied from the splicer 33 between the pressure belt 123 and the upper roll 124.

[0081] The single facer 13 has preheaters 141 and 142. The preheater 141 preheats the back liner C1. The preheater 141 is arranged adjacent to the preheat roll 133. The preheater 141 has two preheat rolls 151 and 152 arranged in the Z direction. The back liner C1 is wrapped around the preheat rolls 151 and 152, thereby heating the back liner C1. The preheat rolls 151 and 152 have a winding amount adjustment device (not shown), and steam is supplied inside to heat them to a predetermined temperature. Multiple guide rolls 153 are provided on the upstream and downstream sides of the preheat rolls 151 and 152.

[0082] The preheater 142 preheats the medium B1. The preheater 142 is disposed adjacent to the preheat roll 131. The preheater 142 has one preheat roll 161 and an angle adjustment roll 163. The medium B1 is wrapped around the preheat roll 161, thereby heating the medium B1. The angle adjustment roll 163 moves around the preheat roll 161, thereby adjusting the contact position where the medium B1 comes into contact with the outer circumferential surface of the preheat roll 161. Steam is supplied to the inside of the preheat roll 161, and the preheat roll 161 is heated to a predetermined temperature. A guide roll 162 is provided upstream of the preheat roll 161.

[0083] Additionally, the single facer 13 is provided with a take-up conveyor 28 at the outlet for the single-faced cardboard sheet D1. The take-up conveyor 28 guides the single-faced cardboard sheet D1 formed by the single facer 13 and supplies it to the bridge 14 (see FIG. 1). The take-up conveyor 28 has a first lower belt 172, a second lower belt 173, and an upper belt 174. The first lower belt 172 and the upper belt 174 are arranged diagonally upward, while the second lower belt 173 is arranged horizontally. The first lower belt 172, the second lower belt 173, and the upper belt 174 can be driven by a drive device (not shown). The single-faced cardboard sheet D1 is sandwiched and transported between the first lower belt 172, the second lower belt 173, and the upper belt 174.

[0084] Therefore, the back liner C1 is supplied from the splicer 33 to the single facer 13 via the preheater 141. After being wound around the preheating roll 133, the back liner C1 is transferred to the nip between the pressure belt 123 and the upper roll 124 together with the pressure belt 123 guided by the belt roll 121. On the other hand, the medium B1 is supplied from the splicer 31 to the single facer 13 via the preheater 142. After being wound around the preheating roll 131, the medium B1 is processed into a corrugated shape at the meshing portion between the upper roll 124 and the lower roll 125, and is guided by the upper roll 124. Pressure Belt 123 and Upper roll 124 The sheet is transferred to the nip portion.

[0085] After being processed into a corrugated shape at the meshing portion between the upper and lower rolls 124 and 125, the medium B1 is glued by a gluing device 126. The glue stored in a glue dam 127 adheres to a rotating gluing roll 128, and the amount of glue applied to the outer peripheral surface is adjusted by a meter roll 129. The medium B1, which has been processed into a corrugated shape at the meshing portion between the upper and lower rolls 124 and 125, comes into contact with the gluing roll 128 and is glued to the top of each corrugation. When the glued medium B1 is transferred to the nip portion between the pressure belt 123 and the upper roll 124, it is bonded to a back liner C1, forming a single-faced cardboard sheet D1.

[0086] The single facer 13 is provided with a sheet splice detection unit 61, which includes an ultrasonic sensor 61a for detecting the spliced ​​portion of the medium B1 and an ultrasonic sensor 61c for detecting the spliced ​​portion of the back liner C1. The ultrasonic sensor 61a is disposed between the fixed roll 110 of the splicer 31 and the guide roll 162 of the preheater 142. The ultrasonic sensor 61a detects the spliced ​​portion of the medium B1 transported between the fixed roll 110 of the splicer 31 and the guide roll 162 of the preheater 142. The ultrasonic sensor 61a is not limited to this location. The ultrasonic sensor 61a may be disposed between the dancer roll 109 of the splicer 31 and the preheat roll 131 of the single facer 13. In this case, the dancer roll 109 moves and pushes out the medium B1 that has been retained therein during splicing, so the ultrasonic sensor 61a is preferably disposed downstream of the maximum travel position of the dancer roll 109.

[0087] The ultrasonic sensor 61c is disposed between the guide rolls 153 of the preheater 141. The ultrasonic sensor 61c detects the spliced ​​portion of the back liner C1 being transported between the guide rolls 153 of the preheater 141. The position of the ultrasonic sensor 61c is not limited to this position. The ultrasonic sensor 61c may be disposed between the dancer roll 109 of the splicer 33 and the preheating roll 133 of the single facer 13. In this case, since the dancer roll 109 moves and sends out the back liner C1 that has been retained during splicing, it is preferable that the ultrasonic sensor 61c be disposed downstream of the maximum movement position of the dancer roll 109.

[0088] The single facer 13 is provided with a crushing device 63a as a corrugation deformation device 63 that forms a corrugation deformation portion in the single-faced cardboard sheet D1. The crushing device 63a is disposed downstream of the take-up conveyor 28, between the single facer 13 and the bridge 14. The crushing device 63a forms a corrugation deformation portion by crushing and deforming the medium B1 of the single-faced cardboard sheet D1 formed by bonding together the medium B1 processed into a corrugated shape by the single facer 13 and the back liner C1.

[0089] Here, the positions of the ultrasonic sensors 61a and 61c as the sheet splice detection unit 61 arranged around the single facer 13 and the crushing device 63a as the ridge deformation device 63 have been described. Although not shown, the ultrasonic sensors 61b and 61d as the sheet splice detection unit 61 arranged around the single facer 17 and the crushing device 63b as the ridge deformation device 63 are also arranged in the same positions.

[0090] <Double Facer> FIG. 9 is a schematic diagram of the area around the double facer to explain the flow of the front liner and single-faced cardboard sheets.

[0091] As shown in FIG. 9, paper guide devices 30 are provided at the exits of bridges 14 and 18, respectively. Paper guide devices 30 include twisting rollers (not shown), which contact the top surfaces of single-faced cardboard sheets D1 and D2, i.e., back liners C1 and C2. With the twisting rollers in contact with the single-faced cardboard sheets, a moving device (not shown) moves one end of the twisting roller in the X direction. This tilts the twisting roller in the X direction, and single-faced cardboard sheets D1 and D2 are guided toward the twisting roller. This adjusts the Y-direction positions of single-faced cardboard sheets D1 and D2, preventing meandering or uneven conveyance in either direction.

[0092] The preheater 20 is configured by rotatably supporting preheating rolls 41, 42, and 43 on a frame 181. The preheating rolls 41, 42, and 43 heat the front liner A, single-faced cardboard sheet D2, and single-faced cardboard sheet D1. Guide rolls 182a, 182b, and 182c and wrap angle adjusting rolls 183a, 183b, and 183c are disposed upstream of the preheating rolls 41, 42, and 43 in the conveyance direction, respectively, and guide rolls 184a, 184b, and 184c are disposed downstream of the preheating rolls 41, 42, and 43, respectively. The wrap angle adjusting rolls 183a, 183b, and 183c move in the circumferential direction of the preheating rolls 41, 42, and 43 to adjust the wrap angles of the front liner A, single-faced cardboard sheet D2, and single-faced cardboard sheet D1, thereby adjusting the preheating temperature.

[0093] The glue machine 21 is configured by gluing rolls 44, 45 rotatably supported on a frame 185. Each gluing roll 44, 45 applies glue from glue dams 186a, 186b to the corrugations B2, B1 of the single-faced cardboard sheet D2 and the single-faced cardboard sheet D1, respectively. Meter rolls 187a, 187b, which adjust the amount of glue applied, are arranged in contact with the gluing rolls 44, 45, and rider rolls 188a, 188b are arranged opposite the gluing rolls 44, 45. Preheaters 190, 191 of the double facer 22 are rotatably supported on a frame 189. The front liner A is guided to the double facer 22 via the preheater 190, and the single-faced cardboard sheets D1, D2 are guided to the double facer 22 via the preheater 191.

[0094] The sheet splicing detection unit 61 is provided with an ultrasonic sensor 61e that detects the spliced ​​portion of the front liner A. The ultrasonic sensor 61e is disposed between the fixed roll 111 of the splicer 35 and the guide roll 182a of the preheater 20. The ultrasonic sensor 61e detects the spliced ​​portion of the front liner A transported between the fixed roll 111 of the splicer 35 and the guide roll 182a of the preheater 20. The position of the ultrasonic sensor 61e is not limited to this. The ultrasonic sensor 61e may be disposed between the dancer roll 109 of the splicer 35 and the preheater 190 of the double facer 22. In this case, the dancer roll 109 moves and sends out the front liner A that has been retained therein during splicing, so the ultrasonic sensor 61e is preferably disposed downstream of the maximum movement position of the dancer roll 109.

[0095] The single-faced corrugated cardboard splice detection unit 62 includes laser displacement meters 62a and 62b that detect the splice portions and corrugation deformation portions of the single-faced cardboard sheets D1 and D2. The laser displacement meters 62a and 62b are disposed between the paper guide device 30 and the glue rolls 44 and 45 of the glue machine 21. More specifically, the laser displacement meters 62a and 62b are disposed between the preheating rolls 42 and 43 of the preheater 20 and the glue rolls 44 and 45 of the glue machine 21. The laser displacement meters 62a and 62b measure the thickness of the single-faced cardboard sheets D1 and D2 transported between the paper guide device 30 and the glue rolls 44 and 45 of the glue machine 21. More specifically, the laser displacement meters 62a, 62b detect the splice portions and corrugation deformation portions based on the thickness of the single-faced cardboard sheets D1, D2 transported between the preheating rolls 43, 42 of the preheater 20 and the gluing rolls 45, 44 of the glue machine 21.

[0096] Furthermore, for example, the laser displacement meters 62a, 62b are disposed in positions facing the guide rolls 184c, 184b. Because the single-faced cardboard sheets D1 and D2 are in contact with the guide rolls 184c, 184b, shaking during conveyance is suppressed, allowing the laser displacement meters 62a, 62b to detect spliced ​​portions and corrugation deformation portions with high accuracy. However, the positions of the laser displacement meters 62a, 62b are not limited to these positions. The laser displacement meters 62a, 62b may be disposed anywhere between the bridges 14, 18 and the double facer 22.

[0097] <Specific configuration of the control device> The configuration of the control device will be described below. As shown in Fig. 2, the control device 64 has a splicing time setting unit 71, a determination unit 72, and a bridge retention amount calculation unit 73.

[0098] The splicing time setting unit 71 sets the splicing time of the front liner A, the corrugations B1, B2, and the back liners C1, C2 in the splicers 31, 32, 33, 34, and 35. The splicing time setting unit 71 sets the splicing time of the corrugations B1, B2, and the back liners C1, C2 in the splicers 31 and 33 and the splicers 32 and 34, particularly during a lot change. The splicing time setting unit 71 sets the splicing time of at least one of the splicers 31 and 32 and the splicers 33 and 34 so that the spliced ​​portions of the back liners C1, C2 are located downstream in the sheet conveying direction from the spliced ​​portions of the corrugations B1, B2 at the joining position of the corrugated corrugations B1, B2 and the back liners C1, C2.

[0099] That is, the splicing timings of the splicers 31, 32 and the splicers 33, 34 are set so that the spliced ​​portion of the back liners C1, C2 precedes the spliced ​​portion of the back liners C1, C2 by a predetermined distance at the joining position of the corrugated cores B1, B2 and the back liners C1, C2. In this case, the splicing timing setting unit 71 sets the splicing timing of at least one of the splicers 31, 32 and the splicers 33, 34 based on a second distance from the sheet splicing position of the cores B1, B2 at the splicers 31, 32 to the sheet joining position at the single facers 13, 17, a third distance from the sheet splicing position of the back liners C1, C2 at the splicers 33, 34 to the sheet joining position at the single facers 13, 17, the conveyance speeds of the cores B1, B2 and the back liners C1, C2, and the stepping rate of the cores B1, B2.

[0100] Here, a method for setting the splicing timing of splicer 31, which splices corrugation medium B1, and splicer 33, which splices back liner C1, will be described. The same applies to a method for setting the splicing timing of splicer 32, which splices corrugation medium B2, and splicer 34, which splices back liner C2.

[0101] Using FIG. 8, various symbols will be described. The second distance L2 is the distance from the sheet splicing position P31 of the core B1 in the splicer 31 to the sheet bonding position P13 in the single facer 13. The third distance L3 is the distance from the Sheet splicing position (not shown) of the back liner C1 in the splicer 33 to the sheet bonding position P13 in the single facer 13. The conveying speed V is the conveying speed of the cores B1, B2 and the back liners C1, C2, and they have the same speed. The stepping rate R is the ratio of the length of the core B1 before and after being subjected to the waveform processing.

[0102] In the corrugating machine of this embodiment, from the positional relationship among the splicer 31, the single facer 13, and the splicer 33, the third distance L3 is longer than the second distance L2, that is, the relationship is L2 < L3. The time TB for the paper splicing part of the core B1 to reach the sheet bonding position P13 of the single facer 13 from the sheet splicing position P31 of the splicer 31 is given by the following formula. TB = L2 / VR On the other hand, the time TC for the paper splicing part of the back liner C1 to reach the sheet bonding position P13 of the single facer 13 from the Sheet splicing position of the splicer 33 is given by the following formula. TC = L3 / V

[0103] Here, since L2 < L3, TB (L2 / VR) < TC (L3 / V). That is, when the cores B1, B2 and the back liners C1, C2 are simultaneously spliced by the splicers 31, 33, at the sheet bonding position P13, the paper splicing part of the core B1 will Back liner C1, C2 precede the paper splicing part of the Back liner C1, C2 by a time difference ΔT (TC - TB) n. Therefore, under the above-mentioned conditions, at the sheet bonding position P13, it is necessary to set the paper splicing timing so that the paper splicing part of the

[0104] That is, at the sheet bonding position P13, the splicing timing of the core B1 must be delayed relative to the splicing timing of the back liner C1 by the sum of the time difference ΔT and the time Tn (N / V) corresponding to the predetermined distance N (ΔT+Tn). In this case, the time TB1 at which the spliced ​​portion of the core B1 reaches the sheet bonding position P13 of the single facer 13 is TB+Tm(ΔT+Tn), and the condition for TB1>TC is given by the following formula. L2 / V×R+(L3 / V-L2 / VR)+N / V>L3 / V

[0105] The control device 64 operates the splicers 31 and 33 at the set splicing times so as to satisfy this formula. The control device 64 operates the splicers 31 and 33 at the splicing timing set by the splicing timing setting unit 71 for splicing the sheets of the corrugated fiberboard B1 by the splicer 31 and the splicing timing set by the splicing timing setting unit 71 for splicing the back liner C1 by the splicer 33. As a result, at the sheet bonding position P13 of the single facer 13, the spliced ​​portion of the back liner C1 precedes the spliced ​​portion of the corrugated fiberboard B1 by a predetermined distance N. Here, this predetermined distance N is a distance that makes it difficult for poor bonding between the spliced ​​portion of the back liner C1 and the spliced ​​portion of the corrugated fiberboard B1 to occur, and also a distance that prevents the defective length of the single-faced cardboard sheet D1 from becoming longer than necessary. The predetermined distance N is preferably shorter than the length of the plate-shaped double-faced cardboard sheet F cut by the cutoff 25, for example, a length in the range of 100 mm to 600 mm.

[0106] In the above description, at the sheet bonding position P13, Back liner C1, C2 The splicing timing of the back liner C1 is delayed relative to the splicing timing of the back liner C1 so that the splicing portion of the back liner C1 precedes the splicing portion of the core B1 by a predetermined distance N. In other words, the control device 64 maintains the splicing timing of the splicer 33 of the back liner C1 as before, and executes control to delay the splicing timing of the splicer 33 of the core B1. In this case, the control device 64 only needs to control at least one of the splicing timing of the splicer 33 of the back liner C1 and the splicing timing of the splicer 33 of the core B1.

[0107] In the above description, the positional relationship between the splicer 31, the single facer 13, and the splicer 33 is described as the second distance L2<the third distance L3. However, even if the positional relationship between the splicer 31, the single facer 13, and the splicer 33 is the second distance L2>the third distance L3 or the second distance L2=the third distance L3, the splicing timing of the core B1 and the splicing timing of the back liner C1 can be set in a similar manner.

[0108] Returning to Figure 2, the splicing time setting unit 71 also sets the splicing time for the front liner A based on the bridge retention amount of the single-faced cardboard sheet D1. When a lot is changed, the types of the front liner A, core B1, and back liner C1 are changed. At this time, the splicing time setting unit 71 sets the splicing time for the front liner A based on the bridge retention amount of the single-faced cardboard sheet D1 calculated by the bridge retention amount calculation unit 73, which will be described later. In other words, the splicing time setting unit 71 sets the splicing time for the front liner A so that the splicing portion of the front liner A approximately coincides with each splicing portion of the single-faced cardboard sheet D1 in the sheet conveyance direction.

[0109] The determination unit 72 determines whether the spliced ​​portion of the back liner C1 precedes the spliced ​​portion of the corrugation medium B1 at the sheet bonding position P13 of the single facer 13. The ultrasonic sensor 61a is disposed between the splicer 31 and the single facer 13, and the ultrasonic sensor 61c is disposed between the splicer 33 and the single facer 13. The ultrasonic sensors 61a and 61c output their detection results to the control device 64. The ultrasonic sensor 61a detects the spliced ​​portion of the corrugation medium B1, and the ultrasonic sensor 61c detects the spliced ​​portion of the back liner C1. The determination unit 72 compares the detection time of the spliced ​​portion of the corrugation medium B1 by the ultrasonic sensor 61a with the detection time of the spliced ​​portion of the back liner C1 by the ultrasonic sensor 61c, and determines whether the spliced ​​portion of the corrugation medium B1 or the spliced ​​portion of the back liner C1 precedes.

[0110] The bridge retention amount calculation unit 73 calculates the bridge retention amount of the single-faced corrugated cardboard sheet D1 retained on the bridge 14 based on the detection results of the sheet splice detection unit 61 and the single-faced corrugated cardboard splice detection unit 62. Specifically, the bridge retention amount calculation unit 73 calculates the bridge retention amount based on the detection results of the splice portion of the back liner C1 by the ultrasonic sensor 61c and the detection results of the splice portion of the back liner C1 by the laser displacement meter 62a. The bridge retention amount calculation unit 73 calculates the bridge retention amount (length) of the single-faced corrugated cardboard sheet D1 from the sheet splice detection unit 61 to the single-faced corrugated cardboard splice detection unit 62 based on the time when the ultrasonic sensor 61c detected the splice portion of the back liner C1, the time when the laser displacement meter 62a detected the splice portion of the back liner C1, and the conveyance speed of the single-faced corrugated cardboard sheet D1.

[0111] When the determination unit 72 determines that the spliced ​​portion of the back liner C1 precedes the spliced ​​portion of the core B1 at the sheet bonding position P13 of the single facer 13, the bridge retention amount calculation unit 73 calculates the bridge retention amount based on the detection results of the sheet splicing detection unit 61 and the single-faced corrugated cardboard splicing detection unit 62. On the other hand, when the determination unit 72 determines that the spliced ​​portion of the back liner C1 does not precede the spliced ​​portion of the core B1 at the sheet bonding position P13 of the single facer 13, the bridge retention amount calculation unit 73 does not calculate the bridge retention amount based on the detection results of the sheet splicing detection unit 61 and the single-faced corrugated cardboard splicing detection unit 62.

[0112] The bridge retention amount calculation unit 73 can also calculate the bridge retention amount of the single-faced corrugated cardboard sheet D1 retained on the bridge 14, based on the operation time of the corrugation deformation device 63 (crushing device 63a) and the detection time of the single-faced corrugated cardboard splicing detection unit 62. In other words, the bridge retention amount calculation unit 73 calculates the bridge retention amount (length) of the single-faced corrugated cardboard sheet D1 from the corrugation deformation device 63 to the single-faced corrugated cardboard splicing detection unit 62, based on the time when the corrugation deformation device 63 deforms the corrugation of the corrugation medium B1, the time when the laser displacement meter 62a detects the corrugation deformed portion of the corrugation medium B1, and the conveyance speed of the single-faced corrugated cardboard sheet D1.

[0113] Here, we have explained the processing of the core B1, back liner C1, and single-sided cardboard sheet D1 by the paper splicing time setting unit 71, judgment unit 72, and bridge retention amount calculation unit 73, but the processing of the core B2, back liner C2, and single-sided cardboard sheet D2 is similar.

[0114] The control device 64 also controls the operation timing of the defective product ejection device 26 based on the position information of the spliced ​​portion detected by the sheet splicing detection unit 61 and the position information of the corrugated mountain deformation portion detected by the single-faced corrugated cardboard splicing detection unit 62. The control device 64 operates the defective product ejection device 26 at a predetermined timing to remove defective double-faced corrugated cardboard sheets F having spliced ​​portions or corrugated mountain deformation portions from the conveying line.

[0115] <Shape of single-faced corrugated cardboard sheet> Figure 10 is a schematic diagram showing a single-faced cardboard sheet, Figure 11 is a schematic diagram showing the splice portion of a single-faced cardboard sheet, Figure 12 is a schematic diagram showing a defect at the splice portion of a single-faced cardboard sheet, and Figure 13 is a schematic diagram showing the corrugation deformation portion of a single-faced cardboard sheet.

[0116] As shown in Figure 10, for example, single-faced cardboard sheet D1 is constructed by attaching a sheet-shaped back liner C1 to a corrugated corrugation medium B1. If there are no splices in the corrugation medium B1 and the back liner C1, and the corrugation shape of the corrugation medium B1 is appropriate, single-faced cardboard sheet D1 has a normal thickness H1. Note that, since the thickness of single-faced cardboard sheet D1 varies due to manufacturing errors, it is preferable that the normal thickness H1 be within the normal thickness range H1a to H1b. Note that the same applies to single-faced cardboard sheet D2.

[0117] As shown in FIG. 11, as described above, at the bonding position between the core B1 and the back liner C1, the seam of the back liner C1 is located downstream in the sheet conveyance direction X1 from the seam portion B1c of the core B1, and the seaming is performed. At this time, at the seam portion B1c of the core B1, since the shape of the stepped portion becomes inappropriate, a bonding failure between the core B1 and the back liner C1 is likely to occur over a predetermined length from the position of the seam portion B1c of the core B1. However, for the single-sided corrugated sheet D1, since the seam portion C1c of the back liner C1 precedes, even if a bonding failure occurs at the seam portion B1c of the core B1, the thickness can be measured at a position where the seam portion C1c of the back liner C1 is located. At this time, the single-sided corrugated sheet D1 becomes thicker by the thickness of one back liner C1 and the thickness of the double-sided tape Tc compared to the normal thickness H1, and becomes a thickness H2 (H1 < H2). The control device 64 (see FIG. 3) detects the seam portion C1c of the back liner C1 in the single-sided corrugated sheet D1 based on the determination result of H1 < H2.

[0118] On the other hand, as shown in FIG. 12, at the bonding position between the core B1 and the back liner C1, contrary to that shown in FIG. 11, when the seaming is performed such that the seam portion B1c of the core B1 is located upstream in the sheet conveyance direction X1 from the seam portion C1c of the back liner C1, the single-sided corrugated sheet D1 has the seam portion B1c of the core B preceding the seam portion C1c of the back liner C1. At this time, at the seam portion B1c of the core B1, since the shape of the stepped portion becomes inappropriate, a bonding failure between the core B1 and the back liner C1 is likely to occur over a predetermined length from the position of the seam portion B1c of the core B1. In this case, the thickness of the single-sided corrugated sheet D1 cannot be measured at a position where the seam portion C1c of the back liner C1 is located.

[0119] As shown in Figure 13, the single-faced corrugated cardboard sheet D1 is constructed by attaching a sheet-shaped back liner C1 to a corrugated corrugated medium B1, but the corrugations of the medium B1 are crushed to form a corrugation-deformed portion B1d. The corrugation-deformed portion B1d is formed intentionally by the operation of the corrugation-deforming device 63, or naturally by malfunction of the single facer 13, etc. At this time, the single-faced corrugated cardboard sheet D1 becomes thinner than the normal thickness H1, and has a thickness H3 (H3

[0120] Although the single-faced corrugated cardboard sheet D1 has been described here, the same applies to the single-faced corrugated cardboard sheet D2.

[0121] <Operation of the corrugated cardboard sheet manufacturing equipment> FIG. 14 is a flowchart showing a method for manufacturing a cardboard sheet.

[0122] The method for manufacturing cardboard sheets includes a step of splicing a following sheet onto a preceding sheet in cores B1, B2, a step of splicing a following sheet onto a preceding sheet in back liners C1, C2, a step of controlling the splicing timing of at least one of cores B1, B2 and back liners C1, C2 so that the splicing portion of the back liners C1, C2 is located downstream of the splicing portion of cores B1, B2 in the sheet conveying direction X1 at the bonding position between cores B1, B2 and back liners C1, C2, and a step of detecting the splicing portion of the back liners C1, C2 based on the thickness of single-sided cardboard sheets D1, D2 to which cores B1, B2 and back liners C1, C2 are bonded.

[0123] ​3 and 14, in step S11, the control device 64 starts the operation of the corrugating machine 10. At this time, a predetermined type of front liner A, corrugating mediums B1 and B2, and back liners C1 and C2 are loaded in the corrugating machine 10. In step S12, the control device 64 activates the corrugation deformation device 63, and in step S13, the control device 64 starts counting the number of corrugations of the corrugations of the corrugations B1 and B2 after the corrugation deformation device 63 is activated.

[0124] In step S14, the control device 64 determines whether the single-faced corrugated cardboard splicing detection unit 62 has detected a corrugation deformation portion. If the control device 64 determines that the single-faced corrugated cardboard splicing detection unit 62 has not detected a corrugation deformation portion (No), the control device 64 continues to wait. On the other hand, if the control device 64 determines that the single-faced corrugated cardboard splicing detection unit 62 has detected a corrugation deformation portion (Yes), in step S15, the control device 64 stops counting the number of corrugations of the corrugations of the corrugations B1 and B2. In step S16, the control device 64 calculates the bridge retention amount based on the counted number of corrugations of the corrugations B1 and B2, the conveying speed, and the run-up rate. Then, in step S17, the control device 64 starts production of the corrugated cardboard sheet.

[0125] In step S18, the control device 64 determines whether or not to change the lot. The control device 64 determines whether or not to change the lot, for example, based on the presence or absence of a lot change signal input from a production management device (not shown). If the control device 64 determines that a lot change is not to be performed (No), it continues production of the cardboard sheets. On the other hand, if the control device 64 determines that a lot change is to be performed (Yes), in step S19, the control device 64 starts splicing control to change the types of the front liner A, the cores B1 and B2, and the back liners C1 and C2.

[0126] That is, the control device 64 controls the timing of splicing the front liner A, the corrugations B1, B2, and the back liners C1, C2 by the splicers 31, 32, 33, 34, 35. Specifically, the control device 64 controls the splicing timing of at least one of the splicers 31, 32 and the splicers 33, 34 so that the spliced ​​portions of the back liners C1, C2 are located downstream in the sheet conveying direction from the spliced ​​portions of the corrugations B1, B2 at the joining position of the corrugated corrugations B1, B2 and the back liners C1, C2. The control device 64 also controls the splicing timing of the front liner A based on the amount of bridge retention of the single-faced cardboard sheets D1, D2.

[0127] In step S20, the control device 64 determines whether the sheet splice detection unit 61 has detected the spliced ​​portions of the corrugations B1 and B2 and the spliced ​​portions of the back liners C1 and C2. If the control device 64 determines that the sheet splice detection unit 61 has not detected all of the spliced ​​portions of the corrugations B1 and B2 and the back liners C1 and C2 (No), the control device 64 waits. On the other hand, if the control device 64 determines that the sheet splice detection unit 61 has detected all of the spliced ​​portions of the corrugations B1 and B2 and the back liners C1 and C2 (Yes), the control device 64 begins tracking the spliced ​​portions of the corrugations B1 and B2 and the back liners C1 and C2 in step S21.

[0128] In step S22, the control device 64 determines whether the spliced ​​portions of the back liners C1 and C2 are ahead of the spliced ​​portions of the corrugations B1 and B2 at the bonding position between the corrugations B1 and B2 and the back liners C1 and C2. If the control device 64 determines that the spliced ​​portions of the back liners C1 and C2 are ahead of the spliced ​​portions of the corrugations B1 and B2 at the bonding position between the corrugations B1 and B2 and the back liners C1 and C2 (Yes), then in step S23, the control device 64 determines whether the single-faced corrugated cardboard splice detection unit 62 has detected the spliced ​​portions of the back liners C1 and C2. If the control device 64 determines that the single-faced corrugated cardboard splice detection unit 62 has not detected all of the spliced ​​portions of the back liners C1 and C2 (No), the control device 64 remains in standby mode.

[0129] On the other hand, when the control device 64 determines that the single-faced corrugated cardboard splice detection unit 62 has detected all of the splices of the back liners C1 and C2 (Yes), in step S24 the control device 64 recalculates the bridge retention amount based on the detection time of the splices of the back liners C1 and C2 by the sheet splice detection unit 61, the detection time of the splices of the back liners C1 and C2 by the single-faced corrugated cardboard splice detection unit 62, the back liners C1 and C2, and the conveying speed.Then, the bridge retention amount calculated in step S16 is replaced with the bridge retention amount calculated in step S24.

[0130] Also, in step S22, if the control device 64 determines (No) that the splice portion of the back liners C1, C2 is not ahead of the splice portion of the cores B1, B2 at the bonding position between the cores B1, B2 and the back liners C1, C2, it does not recalculate the bridge retention amount.

[0131] In addition, if the lot of the back liners C1, C2 is not changed and only the lot of the front liner A or the cores B1, B2 is changed, the control device 64 does not recalculate the bridge retention amount in step S24. Also, if the paper splicing is due to a shortage of roll paper in the back liners C1, C2 rather than a lot change of the back liners C1, C2, the control device 64 may recalculate the bridge retention amount in step S24.

[0132] In the above explanation, when the corrugating machine 10 starts operating, the corrugation deformation device 63 is activated and the single-face corrugated cardboard splice detection unit 62 detects the corrugation deformation portion, thereby calculating the bridge retention amount, but the calculation time of the bridge retention amount is not limited to this time and may be performed at any time. In this case, it may be performed when the splice portion of the back liners C1, C2 does not precede, or it may be performed at any timing by the operator.

[0133] [Effects of this embodiment] The cardboard sheet manufacturing device of the first embodiment includes splicers (second splicing devices) 31, 32 that splice a following sheet onto a preceding sheet in cores B1, B2, splicers (third splicing devices) 33, 34 that splice a following sheet onto a preceding sheet in back liners C1, C2, a single-sided cardboard splicing detection unit 62 that detects the spliced ​​portion of the back liners C1, C2 based on the thickness of the single-sided cardboard sheets D1, D2 in which the cores B1, B2 and the back liners C1, C2 are bonded together, and a control device 64 that controls the splicing timing of at least one of the splicers 31, 32 and the splicers 33, 34 so that the spliced ​​portion of the back liners C1, C2 is located downstream of the spliced ​​portion of the cores B1, B2 in the sheet conveying direction X1 at the bonding position of the cores B1, B2 and the back liners C1, C2.

[0134] In the cardboard sheet manufacturing device according to the first aspect, the control device 64 controls the splicing timing so that the spliced ​​portions of the back liners C1, C2 precede the spliced ​​portions of the corrugations B1, B2 at the bonding positions of the corrugations B1, B2 and the back liners C1, C2. Therefore, even if a bonding failure occurs between the corrugations B1, B2 and the back liners C1, C2 at the spliced ​​portions of the corrugations B1, B2, the corrugations B1, B2 and the back liners C1, C2 are properly bonded together at the spliced ​​portions of the back liners C1, C2. This allows the single-face corrugated cardboard splicing detection unit 62 to properly detect the thickness of the single-face corrugated cardboard sheets D1, D2 at the spliced ​​portions of the back liners C1, C2 that precede the spliced ​​portions of the corrugations B1, B2. As a result, it is possible to suppress the detection of the spliced ​​portion of the second sheet being hindered by poor bonding between the cores B1, B2 and the back liners C1, C2 at the spliced ​​portion of the back liners C1, C2.

[0135] The cardboard sheet manufacturing device according to the second aspect is the cardboard sheet manufacturing device according to the first aspect, and furthermore, the control device 64 controls the splicing timing of the splicers 31, 33 and the splicers 32, 34 so that the spliced ​​portion of the back liners C1, C2 precedes the spliced ​​portion of the cores B1, B2 by a predetermined distance at the bonding position of the cores B1, B2 and the back liners C1, C2. This brings the spliced ​​portions of the cores B1, B2 and the back liners C1, C2 within a predetermined distance, thereby shortening the defective length of the cardboard sheet including the spliced ​​portions of the cores B1, B2 and the back liners C1, C2.

[0136] The cardboard manufacturing apparatus according to the third aspect is the cardboard manufacturing apparatus according to the first or second aspect, and further includes a control device 64 having a splicing timing setting unit 71 that sets the splicing timing of the splicers 31, 33 and the splicers 32, 34 based on a second distance from the splicing position by the splicers 31, 33 to the laminating position, a third distance from the splicing position by the splicers 32, 34 to the laminating position, the conveying speeds of the corrugations B1, B2 and the back liners C1, C2, and the run-up rate of the corrugations B1, B2. This makes it possible to appropriately set the splicing timing of the back liners C1, C2 by the splicers 31, 33 and the splicing timing of the corrugations B1, B2 by the splicers 32, 34.

[0137] The cardboard sheet manufacturing device according to the fourth aspect is the cardboard sheet manufacturing device according to any one of the first to fourth aspects, and further includes ultrasonic sensors (third sheet splice detection units) 61c, 61d that detect the spliced ​​portion based on the thickness of the back liners C1, C2 upstream of the lamination position in the sheet conveying direction, bridges 14, 18 that retain single-faced cardboard sheets D1, D2, and a bridge retention amount calculation unit 73 that calculates the retention amount of single-faced cardboard sheets D1, D2 at the bridges 14, 18 based on the detection timing of the spliced ​​portion of the back liners C1, C2 detected by the ultrasonic sensors 61c, 61d and the single-faced cardboard splice detection unit 62. This makes it possible to calculate the retention amount of single-faced cardboard sheets D1, D2 at the bridges 14, 18 with high accuracy.

[0138] The cardboard sheet manufacturing device according to the fifth aspect is a cardboard sheet manufacturing device according to the fifth aspect, further including ultrasonic sensors (second sheet splice detection units) 61a, 61b that detect the spliced ​​portions based on the thicknesses of the cores B1, B2 upstream of the laminating position in the sheet conveying direction, and the control device 64 includes a determination unit 72 that determines whether the spliced ​​portions of the back liners C1, C2 precede the spliced ​​portions of the cores B1, B2. As a result, the determination unit 72 can confirm that the spliced ​​portions of the back liners C1, C2 precede the spliced ​​portions of the cores B1, B2, thereby appropriately calculating the retention amount at the bridges 14, 18.

[0139] The cardboard sheet manufacturing device according to the sixth aspect is a cardboard sheet manufacturing device according to the sixth aspect, further comprising: a bridge retention amount calculation unit 73 that calculates a retention amount when the determination unit 72 determines that the spliced ​​portion of the back liners C1, C2 precedes the spliced ​​portion of the cores B1, B2; and a bridge retention amount calculation unit 73 that does not calculate a retention amount when the determination unit 72 determines that the spliced ​​portion of the cores B1, B2 precedes the spliced ​​portion of the back liners C1, C2. This allows the retention amount at the bridges 14, 18 to be calculated with high accuracy.

[0140] The cardboard manufacturing apparatus according to the seventh aspect is the cardboard manufacturing apparatus according to any one of the first to seventh aspects, further comprising a crest deformation device 63 that deforms the corrugations B1, B2 in the single-faced cardboard sheets D1, D2, the single-faced cardboard splice detection unit 62 is capable of detecting the deformed crest portion deformed by the crest deformation device 63, and the bridge retention amount calculation unit 73 calculates the retention amount of the single-faced cardboard sheets D1, D2 at the bridges 14, 18 based on the deformation time when the crest deformation device 63 deformed the corrugations B1, B2 and the detection time when the single-faced cardboard splice detection unit 62 detected the deformed crest portion. This makes it possible to calculate the retention amount at the bridges 14, 18 without detecting the spliced ​​portions of the back liners C1, C2.

[0141] The method for manufacturing cardboard sheets according to the eighth aspect includes a step of splicing a following sheet onto a preceding sheet in cores B1, B2, a process device for splicing a following sheet onto a preceding sheet in back liners C1, C2, a step of controlling the splicing timing of at least one of cores B1, B2 and back liners C1, C2 so that the splicing portion of the back liners C1, C2 is located downstream of the splicing portion of cores B1, B2 in the sheet conveying direction X1 at the bonding position between cores B1, B2 and back liners C1, C2, and a step of detecting the splicing portion of the back liners C1, C2 based on the thickness of single-sided cardboard sheets D1, D2 to which cores B1, B2 and back liners C1, C2 are bonded. As a result, even if a bonding failure occurs between the corrugations B1, B2 and the back liners C1, C2 at the splice of the corrugations B1, B2, the corrugations B1, B2 and the back liners C1, C2 are properly bonded at the splice of the back liners C1, C2. This allows the single-faced corrugated cardboard splice detection unit 62 to properly detect the thickness of the single-faced corrugated cardboard sheets D1, D2 at the splice of the back liners C1, C2, which precedes the splice of the corrugations B1, B2. As a result, detection of the splice of the second sheet can be prevented from being hindered by a bonding failure between the corrugations B1, B2 and the back liners C1, C2 at the splice of the back liners C1, C2. [Explanation of symbols]

[0142] 10 Corrugating machine (corrugated cardboard sheet manufacturing equipment) 11, 12, 15, 16, 19 Mill roll stand 13,17 Single Facer 14,18 Bridge 20 Preheater 21 Glue Machine 22 Double Facer 23 Rotary Shaft 24 Slitta Scorara 25 cutoff 26 Defective product ejection device 27 Stacker 28,29 Pick-up conveyor 30 Paper guide device 31, 32 Splicer (second splicer) 33, 34 Splicer (third splicer) 35 Splicer (first paper splicer) 41, 42, 43 Preheating roll 44,45 Glue roll 61 Sheet splicing detector 61a, 61b Ultrasonic sensor (second sheet splice detection unit) 61c, 61d Ultrasonic sensor (third sheet splice detection unit) 61e Ultrasonic Sensor 62 Single-sided corrugated cardboard splice detector 62a, 62b Laser displacement meter 63 Stepped Mountain Transformation Device 63a, 63b Crushing device 64 Control device 71 Paper splicing time setting section 72 Judgment section 73 Bridge retention calculation section A. Outer liner (first sheet) B1, B2 core (second sheet) C1, C2 Back liner (third sheet) D1, D2 single-sided corrugated cardboard sheet E, F double-sided cardboard sheet

Claims

1. A cardboard sheet manufacturing device that conveys a cardboard sheet in which a first sheet, a corrugated second sheet, and a third sheet are bonded together, a second splicing device for splicing a succeeding sheet to a preceding sheet in the second sheet; a third splicing device for splicing a succeeding sheet to a preceding sheet in the third sheet; a single-faced corrugated cardboard splice detection unit that detects a third splice portion of the third sheet based on a thickness of the single-faced corrugated cardboard sheet formed by bonding the second sheet and the third sheet together; a control device that controls the splicing timing of at least one of the second splicing device and the third splicing device so that the third splicing portion is located downstream of the second splicing portion of the second sheet in the sheet conveying direction at the joining position of the second sheet and the third sheet; A cardboard sheet manufacturing device comprising:

2. the control device controls the splicing timings of the second splicing device and the third splicing device so that the third splicing unit leads the second splicing unit by a predetermined distance at the laminating position. The cardboard sheet manufacturing apparatus according to claim 1.

3. the control device has a splicing time setting unit that sets splicing times for the second splicing device and the third splicing device based on a second distance from a second splicing position to the laminating position by the second splicing device, a third distance from a third splicing position to the laminating position by the third splicing device, the conveying speeds of the second sheet and the third sheet, and a step rate for the second sheet. The cardboard sheet manufacturing apparatus according to claim 1 or 2.

4. The apparatus includes a third sheet splice detection unit that detects the third splice portion based on the thickness of the third sheet upstream of the laminating position in the sheet conveying direction, a bridge that retains the single-faced corrugated cardboard sheet, and a bridge retention amount calculation unit that calculates the retention amount of the single-faced corrugated cardboard sheet at the bridge based on the detection time of the third splice portion detected by the third sheet splice detection unit and the single-faced corrugated cardboard splice detection unit. The cardboard sheet manufacturing apparatus according to claim 1.

5. a second sheet splicing detection unit that detects the second splicing portion based on a thickness of the second sheet upstream of the laminating position in the sheet conveying direction, and the control device has a determination unit that determines whether the third splicing portion precedes the second splicing portion. The cardboard sheet manufacturing apparatus according to claim 4.

6. When the determination unit determines that the third splicing portion precedes the second splicing portion, the bridge retention amount calculation unit calculates the retention amount, and when the determination unit determines that the second splicing portion precedes the third splicing portion, the bridge retention amount calculation unit does not calculate the retention amount. The cardboard sheet manufacturing apparatus according to claim 5.

7. The single-faced corrugated cardboard sheet has a crest deformation device that deforms the second sheet of the single-faced corrugated cardboard sheet, and the single-faced corrugated cardboard splice detection unit is capable of detecting a deformed crest portion deformed by the crest deformation device, and the bridge retention amount calculation unit calculates the retention amount of the single-faced corrugated cardboard sheet at the bridge based on the deformation time when the crest deformation device deforms the second sheet and the detection time when the single-faced corrugated cardboard splice detection unit detects the deformed crest portion. The cardboard sheet manufacturing apparatus according to claim 4.

8. A method for manufacturing a cardboard sheet in which a first sheet, a corrugated second sheet, and a corrugated third sheet are laminated together, a step of splicing a succeeding sheet onto a preceding sheet in the second sheet; a step of splicing a succeeding sheet onto a preceding sheet in the third sheet; a step of controlling a splicing timing of at least one of the second sheet and the third sheet so that a third splice portion of the third sheet is located downstream in a sheet conveying direction from a second splice portion of the second sheet at a joining position of the second sheet and the third sheet; detecting the third spliced ​​portion based on the thickness of the single-faced corrugated cardboard sheet formed by bonding the second sheet and the third sheet together; A method for manufacturing a cardboard sheet having the above structure.

Images