Abstract: A knife cylinder for a rotary cutter capable to accommodate to increased cutting speed and width of a corrugated cardboard sheet in recent years and low in weight and rotatory inertia and having enough tensile strength, flexural and torsional rigidity, is provided. The cylinder body of the knife cylinder is a hollow cylindrical body consisting of layers of carbon fiber reinforced plastic and has tensile elastic modulus of 206 GPa or higher in axial direction thereof. Preferably the innermost layer is of a CFRP layer 41 with carbon fibers arranged to extend in circumferential direction of the cylinder body, and a plurality of sets of CFRP layers consisting of a layer 42 with carbon fibers arranged to extend in axial direction and layers 42, 44 with carbon fibers arranged to extend in directions inclined by ±30°˜±60° to axial direction of the cylinder are laminated on the innermost layer.

Abstract: A controlling system for a cardboard-sheet manufacturing apparatus includes an FF/FB controlling unit, a PID controller, and a knowledge database. The FF/FB controlling unit differentiates between compensation for a dynamic characteristic and that for a static characteristic based on the knowledge database, and switches between FF control and FB control. The PID controller operates based on a two-degree-of-freedom PID algorithm. The FF/FB controlling unit adjusts a feedback gain based on information stored in the knowledge database.

Abstract: Torque necessary for cutting band-like paper is properly distributed to both of the preceding motor and the following motor, thereby making it possible to accurately cut the band-like paper.

Abstract: A system for fabricating a corrugated board sheet fabricated includes warp status information obtaining means (6, 6A-6H, 7, 7A, 7B, 8, 8A-8H, 240a, 240b, 241a, 241b) for obtaining warp status information concerning status of the warp of the corrugated board sheet fabricated by a corrugated-board fabrication machine (1); running-state information obtaining means (5, 5A-5H) for obtaining running state information concerning a running state of the corrugated-board fabrication machine (1); control variable calculating means (4, 4A-4H) for calculating a control variable of a particular control factor that affects the warp of the corrugated board sheet and that is one among control factors used to control the corrugated-board fabrication machine (1) based on the warp status information of the corrugated board sheet and the running state information of the corrugated-board fabrication machine (1); and control means (5, 5A-5H) for controlling the particular control factor using the control variable calculated by the

Abstract: A double facer for use in a corrugated fiberboard sheet manufacturing system wherein a moisture content of a double faced corrugated fiberboard sheet is set at an optimum value at all times for stably producing the double faced corrugated fiberboard sheet with less bonding failure and less warp. The double facer comprises moisture content detecting means for detecting a moisture content of the double faced corrugated fiberboard sheet after passed through the heating means or for detecting a parameter correlating with the moisture content, and a control means for controlling a heat reception quantity of the double faced corrugated fiberboard sheet on the basis of a detection result from the moisture content detecting means so that the moisture content of the double faced corrugated fiberboard sheet approaches a predetermined optimum moisture content.

Abstract: A bonded sheet material manufacturing system capable of setting a moisture content of various types of sheet members to be bonded to each other to an optimum value for stably producing a bonded sheet material with less bonding failure and less warp at all times, where the sheet members are heated by individual sheet member heating means and then bonded to each other to produce the bonded sheet material. The system comprises a moisture content detecting means provided for at least one of the sheet members for detecting a moisture content of the sheet member or a parameter correlating with the moisture content and a control unit for controlling the sheet member heating means on the basis of detection information from the moisture content detecting means so that the moisture content approaches a predetermined optimum moisture content.

Abstract: This invention relates to a rotary cutoff apparatus, which permits easy speed control without needing high-level skill or technique and also allows ready replacement of its anvil member. The apparatus is provided with a knife cylinder, which has a knife arranged on its outer circumferential surface and is rotatably supported, and an anvil member with which a free edge of the knife can be brought into contact upon rotation of the knife cylinder, whereby a travelling band-shaped sheet is nipped between the knife and the anvil member and is hence cut off. The knife is supported on the knife cylinder via a spring having spring force sufficient to bear cutting force required to cut off the band-shaped sheet so that the knife is displaceable in a loaded direction upon cutting off the band-shaped sheet. The rotary cutoff apparatus according to the present invention can be arranged, for example, in a production line for a band-shaped sheet material such as a corrugated fiberboard sheet.

Abstract: A bonded sheet material manufacturing system capable of setting a moisture content of various types of sheet members to be bonded to each other to an optimum value for stably producing a bonded sheet material with less bonding failure and less warp at all times, where the sheet members are heated by individual sheet member heating means and then bonded to each other to produce the bonded sheet material. The system comprises a moisture content detecting means provided for at least one of the sheet members for detecting a moisture content of the sheet member or a parameter correlating with the moisture content and a control unit for controlling the sheet member heating means on the basis of detection information from the moisture content detecting means so that the moisture content approaches a predetermined optimum moisture content.

Abstract: A double facer for use in a corrugated fiberboard sheet manufacturing system wherein a moisture content of a double faced corrugated fiberboard sheet is set at an optimum value at all times for stably producing the double faced corrugated fiberboard sheet with less bonding failure and less warp. The double facer comprises moisture content detecting means for detecting a moisture content of the double faced corrugated fiberboard sheet after passed through the heatingmeans or for detecting a parameter correlating with the moisture content, and a control means for controlling a heat reception quantity of the double faced corrugated fiberboard sheet on the basis of a detection result from the moisture content detecting means so that the moisture content of the double faced corrugated fiberboard sheet approaches a predetermined optimum moisture content.

Abstract: The present invention relates to a method capable of certainly correcting a phase shift between a plurality of core paper layers. In the method according to this invention, the next phase shift quantity &dgr;′3 is estimated on the basis of a previous measured phase shift value &dgr;1 and the present measured phase shift value &dgr;2 and a single-faced corrugated fiberboard sheet tension changing quantity &Dgr;T1 for correction of the next phase shift quantity &dgr;′3 estimated is calculated to adjust the tension to the single-faced corrugated fiberboard sheet on the basis of the calculated tension changing quantity &Dgr;T1. This invention is effectively applicable when, for example, manufacturing a two-layer core single-faced corrugated fiberboard sheet or the like.

Abstract: The present invention relates to a single-faced corrugated fiberboard sheet manufacturing apparatus and is for the purpose of manufacturing a high-quality single-faced corrugated fiberboard sheet without the occurrence of a pitch slippage or a phase shift among a plurality of corrugating mediums, the breakage of flutes and the occurrence of press marks.

Abstract: The present invention relates to a corrugator and corrugated fiberboard sheet manufacturing method which are capable of accurately adjusting the quantity of moisture included in a sheet to certainly suppress the warp deformation of the sheet with the passage of time. The corrugator has an adhering section equipped with a plurality of pressurizing units separately disposed in series along a sheet conveying direction, where a front linerboard and a rear linerboard are adhered to each other to form a corrugated fiberboard sheet and the corrugated fiberboard sheet formed in the adhering section is processed into a predetermined configuration in a processing section standing on the downstream side of the adhering section.

Abstract: The present invention relates to a sheet tension adjusting method which allows the tension to a single-faced corrugated fiberboard sheet or a liner to be greatly adjusted with a high accuracy to be capable of the adjustment of upward or downward warps of the corrugated fiberboard sheet. In the method according to this invention, when manufacturing a single-faced corrugated fiberboard sheet S.sub.1 in a manner that a liner L.sub.1 is adhered onto a corrugated sheet C.sub.1, the single-faced corrugated fiberboard sheet S.sub.1 is wound around one or more rolls 1 to change a braking force to the roll 1, thereby adjusting the tension to the single-faced fiberboard sheet S.sub.1. Further, this invention is effectively applicable in manufacturing various kinds of corrugated fiberboard sheets.

Abstract: The present invention relates to a single facer, which comprises a humidifying and heating unit placed on the upstream side of an air pressurization corrugating mechanism for humidifying and heating a corrugating medium and a feed mechanism for supplying the corrugating medium, processed by the humidifying and heating unit, to the air pressurization corrugating mechanism at a given speed. The corrugating medium is supplied at the given speed after the humidification and heating process for the corrugating medium, so that an air pressure to be taken at the corrugation is reducible and a predetermined flute configuration is maintainable. In addition, the spring back of the corrugating medium hardly occurs, which makes it possible to manufacture a corrugated fiberboard sheet with a high shock absorbing ability.

Abstract: A first tension adjustor for adjusting the tension of a liner and a pitch measuring device for measuring the corrugation pitch of a first core board of a single-faced corrugated board are used. A first tension controller operates so that the tension acting on the liner is adjusted on the basis of the corrugation pitch of the first core board of the single-faced corrugated board. Further, a second tension adjustor for adjusting the tension of the single-faced corrugated board and a phase shift measuring device for measuring a phase shift between the corrugations of the first core board of the single-faced corrugated board and the corrugations of a second core board to be laminated to the first core board are used. A second tension controller operates so that the tension acting on the single-faced corrugated board is adjusted on the basis of the phase shift measured by the phase shift measuring device.