JP2013202916A - Apparatus for manufacturing corrugated cardboard sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a displacement of a paper splicing part in each machine of an apparatus for manufacturing a corrugated cardboard sheet.SOLUTION: An apparatus for manufacturing a corrugated cardboard sheet includes: machines such as splicers 24, 28 and 33 for performing paper splicing, a single facer 8, a double facer 14, a preheater 34, and a glue machine 35; a plurality of paper splicing part detection sensors 40, 42, 44, 46, 48, 50 and 52 for detecting a position of a paper splicing part of sheet in each machine; sheet feeding amount measuring devices 36 and 38 for measuring a feeding amount of each sheet; and a production management device for determining a displacement whose value is a predetermined value or more at least in one paper splicing position based on a position of each paper splicing part detected by each paper splicing part detection sensor and a measured feeding amount of each sheet.

Description

  The present invention relates to a corrugated sheet manufacturing apparatus, and more particularly to a corrugated sheet manufacturing apparatus that manufactures a corrugated sheet by splicing a core, a back liner, and a front liner.

  Conventionally, in a corrugated cardboard manufacturing apparatus for manufacturing corrugated cardboard sheets, a core and a back liner supplied to a single facer, and a front liner supplied to a double facer are each spliced from an old sheet to a new sheet, Continuous operation is performed.

  With regard to the sheet splicing of this sheet, for example, in Patent Document 1, a sheet is cut with a predetermined length, the amount of cutter displacement relative to the cutting position of the sheet (web) is detected, and based on this amount of displacement, the sheet splicing is performed. A device that feeds out the sheet that has been subjected to the sheeting operation so that the sheet joining portion of the old and new sheets is positioned in the middle of the sheet to be cut, so that the defective sheet generated each time the sheet joining is performed can be minimized. Have been described.

Japanese Patent No. 2873763

  Here, the corrugated board manufacturing apparatus includes a plurality of machines such as a single facer, a preheater, a glue machine, a double facer, a slitter scorer, and a cutter apparatus. In this corrugated sheet manufacturing apparatus, when splicing each sheet of the center core, the back liner, and the front liner, the base paper roll is changed by the splicer, so that a spline point (paper splicing portion) is generated on each sheet. In Patent Document 1 described above, since the cutting error is obtained from the amount of displacement of the cutter with respect to the cutting position of the sheet, it is not possible to grasp the exact position and the amount of displacement of the paper splicing part.

Further, it is impossible to detect which of the plurality of machines constituting the corrugated board manufacturing apparatus causes the misalignment of the paper splicing portion.
In addition, if a sheet with the paper splicing section shifted is supplied to the single facer, the sheet thickness becomes larger than the gap between the corrugated rolls, which may cause jamming of the sheet and cause a temporary line stop. It is necessary to detect the position shift immediately.
Further, if the paper splicing portion is displaced, there is a problem that a sheet including the paper splicing portion cannot be discharged by cutting with a cutter, and a defective sheet is mixed into the product.

  Therefore, the present invention has been made to solve the problems of the prior art, and detects which of the plurality of machines constituting the corrugated board manufacturing apparatus caused the misalignment of the paper splicing section. Accordingly, an object of the present invention is to provide a corrugated sheet manufacturing apparatus that can quickly find out the occurrence of an abnormality in each machine and reduce the production of useless defective sheets as much as possible.

In order to achieve the above-mentioned object, the present invention is a corrugated sheet manufacturing apparatus for manufacturing a corrugated cardboard sheet, wherein a single facer for manufacturing a single-faced corrugated cardboard sheet by bonding a core having a step and a back liner. And a core splicer that splices the center core fed from the core paper holder and supplies it to the single facer, and a back that feeds the back liner sent from the liner base paper hook to the single facer. A liner splicer, a double facer for producing a double-sided corrugated sheet by attaching a front liner to a single-sided corrugated cardboard sheet, a front liner splicer for splicing the front liner fed from the front liner base paper sheet to the double facer, and a double facer Supplied to the single face corrugated sheet and the preheater that heats the front liner and the double facer A glue machine for applying glue to a single-sided corrugated cardboard sheet, a slitter scorer for slitting and ruling the double-sided cardboard sheet, a cutter for cutting the double-sided cardboard sheet to a predetermined cutting length along the sheet flow direction, Center core paper splice detection sensor that detects the splicing section of the core that is arranged on the downstream side of the splicer for the core, and the back that detects the splice section of the back liner that is disposed on the downstream side of the splicer for the back liner. A liner paper joint detection sensor, a front liner paper joint detection sensor that is arranged immediately downstream of the front liner splicer and detects a paper joint part of the front liner, and arranged immediately upstream and downstream of the single facer. A single facer paper joint detection sensor for detecting the paper joint of the single-sided cardboard sheet, and the single-faced cardboard sheet and the front label disposed on the upstream side and the downstream side of the preheater A preheater paper joint detection sensor for detecting the respective paper joints of the liner, and a glue machine paper joint for detecting the respective paper joints of the single-sided cardboard sheet and the front liner, which are arranged immediately upstream and downstream of the glue machine. Part detection sensor, a double facer paper joint detection sensor which is arranged on the upstream side and the downstream side of the double facer and detects each paper joint part of the single-sided cardboard sheet, the front liner and the double-sided cardboard sheet, a core, a back liner, Sheet feed amount measuring device for measuring the feed amount of each of the front liner, single-sided corrugated sheet and double-sided corrugated cardboard sheet, core sheet joint detection sensor, back liner sheet joint detection sensor, front liner sheet joint detection sensor Single facer paper joint detection sensor, preheater paper joint detection sensor, glue machine paper joint detection sensor, and The position shift amount of each sheet is calculated from the position of each sheet splice detected by the double facer sheet splice detection sensor and the sheet feed amount measured by the sheet feed amount device. And a production management device that determines that the misalignment of the paper splicing portion has occurred when at least one of the deviation amounts is equal to or greater than a predetermined value.
In the present invention configured as described above, the center core sheet joint detection sensor, the back liner sheet joint detection sensor, the front liner sheet joint detection sensor, the single facer sheet joint detection sensor, and the preheater sheet joint detection sensor. , Glue machine paper joint detection sensor and double facer paper joint detection sensor detect the position of the paper joint of each sheet such as single-sided cardboard sheet in each machine such as single facer constituting the corrugated sheet manufacturing apparatus In addition, since the production management device determines the misalignment of the paper splicing section from the measured sheet feed amount, it can accurately determine in which machine the misalignment of the paper splicing section has occurred in real time. I can grasp it. In addition, since each of the core, back liner, front liner, single-sided cardboard sheet, and double-sided cardboard sheet is detected separately, the fault of each machine can be detected quickly and accurately. Can be detected.

In the present invention, it is preferable that the portion of the double-sided corrugated cardboard sheet including the paper splicing portion is located on the downstream side of the cutter when the production management device determines that the misalignment of the paper splicing portion has occurred. A defective sheet discharging device is provided.
According to the present invention configured as described above, when the defective sheet discharge device determines that the misalignment of the paper splicing portion has occurred by the production management device, the part of the double-sided cardboard sheet including the paper splicing portion. As a defective sheet, the production of useless defective sheets can be reduced as much as possible, and the paper splicing portion can be reliably prevented from being mixed into a part of the double-sided cardboard sheet.

In the present invention, preferably, when the production management device determines that the misalignment of the paper splicing portion has occurred, the splicer, the single facer, the preheater, the glue machine, or the double facer in which the misalignment has occurred. Identify the machine and notify the outside.
According to the present invention configured as described above, when the production management device determines that the misalignment of the paper splicing portion has occurred, it identifies the misalignment-occurring machine and notifies the outside. As a result, it is possible to quickly find out which machine has an abnormality and respond quickly.

In the present invention, a core sheet joint detection sensor, a back liner sheet joint detection sensor, a front liner sheet joint detection sensor, a single facer sheet joint detection sensor, a preheater sheet joint sensor, a glue machine sheet joint sensor, At least one of the double facer paper joint sensors is a silver paper sensor that detects the silver paper stuck on the paper joint.
According to the present invention thus configured, the position of the paper splicing portion can be detected by a simple sensor using the characteristics of the silver paper stuck to the paper splicing portion.

  According to the corrugated sheet manufacturing apparatus of the present invention, it is possible to detect which of the plurality of machines constituting the corrugated cardboard manufacturing apparatus is causing the misalignment of the paper splicing portion. It is possible to quickly find out the occurrence of abnormality and reduce the production of useless defective sheets as much as possible.

It is a side view showing the whole corrugated cardboard manufacturing device by the embodiment of the present invention. It is the block diagram which showed the main machines and the some paper joint detection sensor which comprise the corrugated-cardboard manufacturing apparatus by embodiment of this invention. It is the first half part of the flowchart which shows the control flow in the corrugated board manufacturing apparatus by embodiment of this invention. It is a second half part of the flowchart which shows the control flow in the corrugated board manufacturing apparatus by embodiment of this invention.

Next, a cardboard sheet manufacturing apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, referring to FIG. 1, the overall structure of a corrugated board manufacturing apparatus according to an embodiment of the present invention will be described. Reference numeral 1 denotes a corrugated cardboard manufacturing apparatus (corrugator machine). The corrugated cardboard manufacturing apparatus 1 manufactures a single-sided corrugated cardboard sheet 6 by bonding a core 2 having corrugated steps and a back liner 4. A single facer 8, a double facer 14 for producing a double-sided cardboard sheet 12 by bonding a front liner 10 to the single-sided cardboard sheet 6, a slitter scorer 16 for slitting and ruling the double-sided cardboard sheet 12, and a double-sided cardboard sheet A cutter 18 that cuts the sheet 12 to a predetermined cutting length L in the sheet flow direction and a stacker 20 that stacks the cut double-sided cardboard sheets are provided.

  As shown in FIG. 1, the corrugated cardboard manufacturing apparatus 1 further includes a core paper base 22 for supplying the core 2 to the single facer 8, and a core core fed from the core base paper holder 22. A core splicer 24 for performing paper splicing, a back liner base paper hook 26 for supplying the back liner 4, and a back liner splicer 28 for splicing the back liner fed from the back liner base paper hook 26. The take-up conveyor 30 for feeding the single-faced cardboard sheet 6 produced by the single facer 8 to the double facer 14, the front liner base paper hook 32 for supplying the front liner 10 to the double facer 14, and the front liner base paper holder 32 A front liner splicer 33 for splicing the fed front liner is provided.

  The corrugated board manufacturing apparatus 1 further glues the single-sided corrugated cardboard sheet 6 and the front liner 10 supplied to the double facer 14 and the heated single-faced cardboard sheet 6 before being supplied to the double facer 14. A glue machine 35 is provided. Further, a defective sheet discharge device 31 that discharges a portion of the double-sided corrugated cardboard sheet including the paper splicing portion as a defective sheet is provided immediately downstream of the cutter 18.

  A first measuring device 36 is provided immediately downstream of the core splicer 24, and a second measuring device 38 is provided immediately upstream of the cutter 18. The first measuring device 36 and the second measuring device 38 are for measuring an actual feed amount (actual feed amount) of a core, a single-sided cardboard sheet, a double-sided cardboard sheet, and the like. It is possible to discriminate an error (positional deviation amount) from the target feed amount (target feed amount), thereby detecting the positional deviation of the sheet splicing portion of each sheet described later. ing.

Here, silver paper is affixed to the paper splicing portions of the core splicer 24, the back liner splicer 28, and the front liner splicer 33 described above so that the operator can recognize the paper splicing portion.
The corrugated sheet manufacturing apparatus 1 includes a number of silver paper sensors (paper) (to be described later) in order to detect the positions of the core, the back liner, the front liner, and the paper joints of the single-sided cardboard sheet and the double-sided cardboard sheet. A joint detection sensor) is provided. This silver paper sensor is a sensor that detects a position in a non-contact manner by detecting a change in a transmission frequency or a phase by using an eddy current generated by electromagnetic induction in silver paper affixed to a sheet.

  Specifically, a first paper splice detection sensor 40 for detecting a core splice is provided immediately downstream of the core splicer 24, and is provided immediately downstream of the back liner splicer 28. Is provided with a second paper joint detection sensor 42 for detecting the paper joint of the back liner, and a third paper for detecting the paper joint of the single-sided cardboard sheet 6 is provided immediately downstream of the single facer 8. A joint detection sensor 44 is provided.

  Further, a pair of fourth paper joint detection sensors 46 for detecting the paper joints of the single-sided corrugated cardboard sheet 6 and the front liner 10 are provided immediately upstream of the preheater 34. A pair of fifth paper splice detection sensors 48 for detecting the paper splices of the single-sided corrugated cardboard sheet 6 and the front liner 10 are provided immediately upstream of 35, and further, a downstream side of the glue machine 35 and the double facer 14. A pair of sixth paper joint detection sensors 50 for detecting the paper joints of the single-sided corrugated cardboard sheet 6 and the front liner 10 are provided on the upstream side. Further, a seventh paper joint detection sensor 52 that detects the paper joint of the double-sided corrugated cardboard sheet 12 is provided immediately downstream of the double facer 14.

Next, as shown in FIG. 2, the corrugated board manufacturing apparatus 1 controls a production management apparatus 60 that controls all the above-described machines such as the single facer 8 and manages production of the manufactured corrugated board sheets. I have.
The production management device 60 sends control signals to the single facer 8, the preheater 34, the glue machine 35, the double facer 14, the slitter scorer 16, the cutter 18, the stacker 20, and the like to control the operation of these machines. Yes.

  In addition, the production management device 60 obtains positional information regarding the position of the detected paper splicing portion of each sheet from the first to seventh paper splicing portion detection sensors 40, 42, 44, 46, 48, 50, 52. In addition, information on the detected feed amount of the core sheet and the double-sided cardboard sheet is received from the first measuring device 36 and the second measuring device 38.

  The production management device 60 includes the positions of the paper splicing portions from the first to seventh paper splicing portion detection sensors 40, 42, 44, 46, 48, 50, 52, the first measuring device 36 and the second measuring ring. Based on the sheet feed amount from the apparatus 38, the splicing portion generated between the immediately upstream side and the immediately downstream side of each machine, that is, the single facer 8, the preheater 34, the glue machine 35, and the double facer 14, is determined. The positional deviation is determined. In other words, the production management device 60 can determine which machine (single facer or the like) caused the misalignment of the paper splicing unit.

  As shown in FIG. 2, an alarm device 62 is further provided. This alarm device 62 is used when the amount of misalignment of the paper splicing portion is a predetermined range or more, for example, twice or more of each machine error. In addition to notifying machine producers, workers, manufacturers, etc. of machine abnormalities, an alarm is issued.

  Next, a control flow by the corrugated board manufacturing apparatus according to the present embodiment will be described with reference to FIGS. 3 and 4, S indicates each step.

  First, S1 to S5 are steps for detecting an abnormality of each splicer 24, 28, 32. That is, in S1, the position of each paper splice (splice point: SP) is detected by a paper splice detection sensor arranged immediately downstream of each splicer. Next, in S2, the feeding amount of each sheet from each splicer 24, 28, 32 to the position of each paper splice detection sensor 40, 42, 46 arranged immediately downstream thereof is measured.

  Next, in S3, the amount of misregistration of each sheet is calculated from the feed amount of each sheet measured in S2 and the position of the paper splice detected by each paper splice detection sensor 40, 42, 46. Further, in S4, it is determined whether or not each of these misregistration amounts is at least twice the mechanical error range (1 m) of the splicer. If NO, the process proceeds to S6, whereas if YES, the process proceeds to S5 to notify / warn that any of the splicers 24, 28, 32 has an abnormality.

  Next, S6 to S10 are steps for detecting an abnormality of the single facer 8. That is, in S6, the position of the sheet joint portion of the sheet (center core, back liner) is detected by the sheet joint detection sensor arranged immediately upstream of the single facer 8. Next, in S7, the sheet (single-sided cardboard sheet) feed amount to the position of the paper splice detection sensor arranged immediately downstream of the single facer 8 is measured. Next, in S8, the amount of sheet misalignment is calculated from the sheet feed amount measured in S7 and the position of the paper splice detection sensor arranged immediately downstream of the single facer 8. Further, in S9, it is determined whether or not the amount of displacement is at least twice the mechanical error range (1 m) of the single facer. If NO, the process proceeds to S11. On the other hand, if YES, the process proceeds to S10 to notify / warn that an abnormality has occurred in the single facer 8.

  Next, S11 to S15 are steps for detecting an abnormality in the preheater 34. In other words, in S11, the position of the sheet joint portion of the sheet (single-sided corrugated cardboard sheet, front liner) is detected by the sheet joint detection sensor arranged immediately upstream of the preheater 34. Next, in S12, the feed amount of the sheet (single-sided cardboard sheet, front liner) to the position of the paper splice detection sensor arranged immediately downstream of the preheater 34 is measured. Next, in S13, the amount of misalignment of the sheet is calculated from the sheet feed amount measured in S12 and the position of the paper splice detection sensor arranged immediately downstream of the preheater 34. Further, in S14, it is determined whether or not the positional deviation amount is at least twice the mechanical error range (1 m) of the preheater. If NO, the process proceeds to S16, while if YES, the process proceeds to S15 to notify / warn that an abnormality has occurred in the preheater 34.

  Next, S16 to S20 are steps for detecting an abnormality of the glue machine 35. In other words, in S16, the position of the sheet joint portion of the sheet (single-sided cardboard sheet, back liner) is detected by the sheet joint detection sensor arranged immediately upstream of the glue machine 35. Next, in S <b> 17, the feeding amount of the sheet (single-sided cardboard sheet, front liner) up to the position of the paper joint detection sensor arranged immediately downstream of the glue machine 35 is measured. Next, in S18, the amount of misalignment of the sheet is calculated from the sheet feed amount measured in S17 and the position of the paper splice detection sensor arranged immediately downstream of the glue machine 35. Further, in S19, it is determined whether or not the amount of misalignment is at least twice the mechanical error range (1 m) of the glue machine. If NO, the process proceeds to S21, while if YES, the process proceeds to S19 to notify / warn that an abnormality has occurred in the glue machine 35.

  Further, S21 to S25 are steps for detecting an abnormality of the double facer 14. That is, in S21, the position of the sheet joint portion of the sheet (single-sided cardboard sheet, front liner) is detected by the sheet joint detection sensor arranged immediately upstream of the double facer 14. Next, in S22, the amount of sheet (double-sided cardboard sheet) fed to the position of the paper splice detection sensor disposed immediately downstream of the double facer 14 is measured. Next, in S23, the amount of misalignment of the sheet is calculated from the sheet feed amount measured in S22 and the position of the paper splice detection sensor disposed immediately downstream of the double facer 14. Further, in S24, it is determined whether or not the amount of positional deviation is at least twice the mechanical error range (1 m) of the double facer. If NO, the process ends. If YES, the process proceeds to S25 to notify / warn that an abnormality has occurred in the double facer 14.

Here, the main cause of the positional deviation at the paper splicing portion in each machine will be described. In the splicer, the delay of the base paper hook and the brake operation of the splicer, incorrect application of the base paper to the dancer roll in the splicer (roll skip), misalignment of the dancer roll position adjustment (potentiometer malfunction at the roll detection position), type Misalignment occurs due to misdetection of the paper splicing part due to the difference in the friction of different base papers (plain paper, water repellent paper, etc.).
If the misalignment of the spliced part occurs due to these causes, in each splicer, correct the timing of brake operation, correct the position where the base paper is put on the dancer roll, check the malfunction of the potentiometer, friction with the sheet Measures and measures such as correction of detection deviation in the measuring roll due to different degrees.

In a single facer, misalignment occurs due to a paper feed error of a heater in the single facer. In the preheater, a positional deviation occurs due to a roll winding angle adjustment deviation or the like. In the double facer, misalignment occurs due to a paper passing error of the heater in the double facer.
When misalignment of the spliced part occurs due to these causes, check and correct whether the paper threading is incorrect in the single facer, correct the roll wrap angle to an appropriate value in the preheater, and check whether the paper threading is incorrect in the double facer. Are checked and corrected, and the misalignment of the paper splicing section by each machine is corrected.

  As described above, in the cardboard sheet manufacturing apparatus according to the present embodiment, the first paper joint detection sensor (core paper joint detection sensor) 40, the second paper joint detection sensor (back liner paper joint detection sensor). 42, fourth paper joint detection sensor (front liner paper joint detection sensor) 46, first, second, and third paper joint detection sensors (single facer paper joint detection sensors) 40, 42, 44, and 4, fifth paper joint detection sensors (preheater paper joint detection sensors) 46, 48, fifth and sixth paper joint detection sensors (glue machine paper joint detection sensors) 48, 50, and sixth, sixth 7 paper joint detection sensors (double facer paper joint detection sensors) 50 and 52 indicate the position of the paper joint of each sheet such as a single-sided cardboard sheet on each machine such as the single facer 8 constituting the corrugated sheet manufacturing apparatus. Detect and further Since the production management device 60 determines the misalignment of the paper splicing portion from the measured sheet feed amounts, it is possible to accurately grasp in which machine the misalignment of the paper splicing portion has occurred in real time. Can do. In addition, since each of the core, back liner, front liner, single-sided cardboard sheet, and double-sided cardboard sheet is detected separately, the fault of each machine can be detected quickly and accurately. Can be detected.

  In addition, the defective sheet discharging device 31 discharges a portion of the double-sided corrugated cardboard sheet including the paper splicing portion as a defective sheet based on the positional deviation of the paper splicing portion obtained from the production management device 60, thereby producing a useless defective sheet. It can be reduced as much as possible, and it is possible to reliably prevent the paper splicing part from being mixed into a part of the double-sided cardboard sheet.

  In addition, when the production management device 60 determines the misalignment of the paper splicing portion by the alarm device 62, the machine in which the misalignment has occurred is identified and notified to the outside. It is possible to find out at an early stage whether or not a problem has occurred and to take a quick response.

  Furthermore, the position of the paper splicing portion can be detected by a simple sensor using the characteristics of the silver paper affixed to the paper splicing portion.

DESCRIPTION OF SYMBOLS 1 Corrugated-sheet manufacturing apparatus 8 Single facer 14 Double facer 24 Center core splicer 28 Back liner splicer 31 Defective sheet discharge device 33 Front liner splicer 34 Preheater 35 Glue machine 36 First measuring device 38 Second measuring device 40 First 1st paper joint detection sensor 42 2nd paper joint detection sensor 44 3rd paper joint detection sensor 46 4th paper joint detection sensor 48 5th paper joint detection sensor 50 6th paper joint detection sensor 52 7th paper Joint detection sensor 60 Production management device 62 Alarm device

Claims (4)

A cardboard sheet manufacturing apparatus for manufacturing a cardboard sheet,
A single facer for manufacturing a single-sided corrugated sheet by bonding a core formed with a step and a back liner;
A core splicer that splices the core sent out from the core for the core and feeds it to the single facer;
A back liner splicer that splices the back liner fed from the liner base paper and supplies it to the single facer;
A double facer that produces a double-sided cardboard sheet by laminating a front liner to a single-sided cardboard sheet;
A front liner splicer that splices the front liner delivered from the front liner base and supplies it to the double facer;
A pre-heater for heating the single-sided cardboard sheet and the front liner supplied to the double facer;
A glue machine that applies glue to the single-sided cardboard sheet supplied to the double facer;
A slitter scorer that applies slit processing and ruled line processing to double-sided cardboard sheets,
A cutter that cuts a double-sided cardboard sheet into a predetermined cutting length along the flow direction of the sheet;
A core sheet joint detection sensor that is disposed immediately downstream of the core splicer and detects a core sheet joint;
A back liner paper joint detection sensor that is disposed immediately downstream of the back liner splicer and detects a paper joint of the back liner;
A front liner paper joint detection sensor that is arranged immediately downstream of the front liner splicer and detects a paper joint of the front liner;
A single facer paper joint detection sensor that is disposed immediately upstream and downstream of the single facer and detects a paper joint of a single-sided cardboard sheet;
A preheater paper joint detection sensor that is disposed on the upstream side and the downstream side of the preheater and detects the paper joints of the single-sided cardboard sheet and the front liner;
A glue machine sheet joint detection sensor that is disposed on the upstream side and the downstream side of the glue machine and detects each sheet joint part of the single-sided cardboard sheet and the front liner;
A double facer paper joint detection sensor that is disposed on the upstream side and the downstream side of the double facer and detects each paper joint of the single-sided cardboard sheet, the front liner, and the double-sided cardboard sheet;
A sheet feed amount measuring device for measuring the feed amount of each of the core, the back liner, the front liner, the single-sided cardboard sheet and the double-sided cardboard sheet;
The above-mentioned core sheet joint detection sensor, back liner sheet joint detection sensor, front liner sheet joint detection sensor, single facer sheet joint detection sensor, preheater sheet joint detection sensor, glue machine sheet joint detection sensor, and From the position of each paper splice detected by the double facer paper splice detection sensor and the feed amount of each sheet measured by the sheet feed device, the amount of misregistration in each sheet is calculated. A production management device that determines that a misalignment of the paper splicing portion has occurred when at least one of the misregistration amounts is a predetermined value or more;
A cardboard sheet manufacturing apparatus comprising:   Immediately downstream of the cutter, when the production management device determines that the misalignment of the paper splicing portion has occurred, a defective sheet that discharges a portion of the double-sided cardboard sheet including the splicing portion as a defective sheet 2. The corrugated board manufacturing apparatus according to claim 1, further comprising a discharge device.   If the production management device determines that the misalignment of the paper splicing portion has occurred, the machine of the splicer, single facer, preheater, glue machine, double facer in which the misalignment of the paper splicing portion has occurred. The cardboard sheet manufacturing apparatus according to claim 1, wherein the cardboard sheet is specified and notified to the outside.   The above-described core sheet joint detection sensor, back liner sheet joint detection sensor, front liner sheet joint detection sensor, single facer sheet joint detection sensor, preheater sheet joint sensor, glue machine sheet joint sensor, and double facer The corrugated sheet manufacturing apparatus according to any one of claims 1 to 3, wherein at least one of the paper joint sensors is a silver paper sensor that detects silver paper affixed to the paper joint.

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