On-line sheeter of printing system and method of changing length of cut

Abstract: A sheeter (40) which can cut a running printed sheet (36) discharged from a web-fed rotary gravure press, a web-fed rotary forms press, etc, with higher accuracy on-line, and can selectively carry out a change of length of cut, accompanied by a change of a printing plate cylinder (22). A drum roller (54) which has the same diameter as that of a plate cylinder in a printing unit or a diameter enlarged by an amount of applied tension, is provided in such a way that it is exchangeable on a sheet guide passage introducing the running printed sheet to a cutting section with the flying knife, etc, is rotationally rotated syncronous with the plate cylinder (22) by a driving shaft of the plate cylinder, and feeds the running printed sheet to the cutting section by winding it. When exchanging the plate cylinder, the existing drum roller (54) is exchanged with another which has the same diameter as that of the plate cylinder to be changed or a diameter enlarged by an amount of applied tension.

Description: The present invention relates to an on-line sheeter of a printing system according to the preamble of claim 1 and a method of changing a length of cut according to the preamble of claim 5. The on-line sheeter can cut running printed sheets discharged from a web-fed rotary gravure press and web-fed rotary forms press at a predetermined length. Up to the present time, when exchanging plate cylinders and changing the length of cut in operation of web-fed rotary press for gravure and forms, the printing systems have been arranged in such a way that the desired section of sheet could be obtained by providing a plurality of folding machines corresponding to the length of cut for folding various running sheets. Those folding machines comprise a plurality of folding cylinders positioned on the running line of sheets, and each of folding cylinders includes a cutting blade for cutting sheets, a needle for supplying sections of sheet being cut or a striking blade, and a gripping apparatus, introducing the section to a stacker. Alternatively, only a variable folding machines sometimes prepares sections of sheet. However, in such conventional system, printed sheets sometimes can not be fed to folding machine. For example, in a case of such label printing which sections of sheet are not fixed, the printed sheets can not be discharged as a section. Such printed sheets are temporarily rewound on a rewinder, then each of desired length of cut is set in an off-line sheeter, and the sheets are cut one by one to be stacked up. Such a sheeter introduces printed sheets supplied from a roll of rewound sheet to a flying knife through a guide roller, compensate roller, and drawing roller, then cut those sheets at predetermined sizes and introduces them to a stack section to pile. In this case, an adjustment of variation of the length of cut is carried out by modifying a press length to a draw roller through an adjustment of a compensate roller position and by controlling a rotating speed of the drawing roller. Controlling rotation of the draw roller is control of circumferential speed, which speed is manually or automatically controlled. The above-mentioned conventional sheeter, however, is arranged on the off-line independant of a printing line, and enters a cutting operation after loading a rewound roll of printed sheet, therefore, its working effectiveness is very low. Moreover, a sheeter itself needs to be changed to a model corresponding to its length of cut when changing the length of cut with an exchange of a printing plate cylinder ( e.g. changing size A to B ). Because of the above-mentioned disadvantages, the conventional printing system is not only unable to cut running printed sheets on line through a sheeter, but also needs to be equipped with a sheeter of a model corresponding to a concerned length of cut when changing the length of cut. Or else, the system has confronted a problem that it has to employ a sheeter which can vary a length of cut on-line. Especially, a drawing roller is controlled using a seperate driving power source in order to inhibit the undesired variation of a length of cut, however, the printing speed of a press varies, thereby controlling a rotation of the draw roller adapting to the variation is very difficult, and the conventional printing system has a disadvantage that it can not control the variation of cut as a result. Another on-line sheeter in a printing system and method of cutting a running printed sheet is known from EP-A-0 494 087. With respect to the prior art the present invention intends to provide an on-line sheeter of a printing system which allows to easily change the cut length and at the same time provides high printing and cutting accuracy. This technical problem is solved by providing an additional drum roller and nip roller in the sheet introducing guide sections as defined in by claim 1. This problem is also solved by the method defined by claim 5. When changing a length of cut of the running printed sheet the drum roller is simultaneously replaced by a drum roller having the same diameter as a plate cylinder or a diameter enlarged by an amount of applied tension when exchanging the plate cylinder of said printing unit. In the above-mentioned arrangement, the sheeter has a drum roller having the same diameter as that of a plate cylinder, a nip roller rotationally contacting with the drum roller, and a running printed sheet continually fed from the printing unit is bitten between these rollers and fed to the cutting section. The drum roller rotates synchronous with the plate cylinder, and the drum roller is exchanged with another drum roller having the same diameter as that of another plate cylinder simultaneously whenever the plate cylinder is exchanged, thereby, a change of a length of cut can be attained by exchanging a drum roller at the same time. Accordingly, such a sheeter can be used on-line, and a lengthof cut also can be changed and adjusted only by exchanging a drum roller. Consequently, a drum roller can be driven through a transmission mechanism so as to automatically synchronous with a speed of a running printed sheet, and a flying knife can always rotate synchronous with any plate cylinder. According to the present invention, a change of a length of cut can be provided at the same time when exchanging a plate cylinder, it is possible to apply a sheet on-line, moreover, there can be attained a very useful effect that setting a length of cut can be easily made. Figure 1 shows an embodiment of a web-fed rotary gravure press including an on-line sheeter. Figure 2 is a plane block diagram of the same press. Figure 3 is a sectional block diagram with reference to the embodiment. Figure 4 is an enlarged block diagram of the sheet introducing guide section of the same on-line sheeter. An embodiment of the on-line sheeter of a press according to the present invention and a method of changing a length of cut, will be described in detail referring to the accompanying drawing hereafter. Figure 1 and 2 are whole arrangement block diagrams of the press including an on-line sheeter with reference to the embodiment. This is an embodiment where the present invention is incorporated to a web-fed rotary gravure press, which rotary press comprises a sheet feeding section 12 loading a pair of web roll 10, an infeeding section 16 introducing a web 14 being supplied from the sheet feeding section 12, a printing unit 18 for printing a sheet, and an outfeeding section 20 for controlling tension applied to a sheet. Said printing unit 18 includes a plate cylinder 22 for printing a sheet, a rotationally driving section 24 for rotatinally driving the plate cylinder 22 is positioned at a side of the printing unit 18. In such an arrangement, the rotationally driving section 24 is provided so as to rotate a driving shaft 30 positioned parallel to a driving line of the web 14 through a driving motor 26 and gear train 28,and a rotating force of the driving axis 30 transmitted through a gear box 32 allows a main axis 34 of the plate cylinder 22 to be rotated. In order to directly introduce and cut at a predetermined amount of print a running printed sheet 36 discharged from such a rotary press, an on-line sheeter 40 according to the embodiment is placed in the following stage of the rotary press. The on-line sheeter 40 comprises a sheet introducing guide section 42 introducing the running printed sheet 36, a cutting section 44, a sheet discharging section 46, and a piling section 48. This particular arrangement will be described hereafter referring to Figure 1 and 2. The sheet introducing guide section 42 serves to receive the running printed sheet discharged from the rotary press and feed it to the cutting section 44, as shown in Figure 3, and directs the running sheet 36 introduced from the front lower portion upwards through a first guide roller 50 and a second guide section 52. In the front of a discharge passage of the second guide roller 52, a drum roller 54 by which the embodiment is characterized is provided. Rewinding the running sheet 36,the drum roller 54 rotationally feeds the running sheet 36 by nipping it between the roller 54 and a nip roller 56 rotationally contacting with the roller 54. The drum roller 54 is a rotary driving drum, and determines the feeding speed of the running sheet 36 with a turning force being transmitted from a driving power source to be described later. The running sheet 36 is discharged through the drum roller 54, and is fed to a drawing roller 60 which is positioned at an inlet port of the cutting section 44 through a compensate roller 53. The cutting section 44 includes a flying knife 62 which is placed above the running sheet 36 discharged from the drawing roller 60, and cuts the running sheet 36 at a predetermined length of cut by its rotation and send it to the sheet discharging section 46. Said drum roller 54 has the same diameter as the plate cylinder 22 mounted on the printing unit 13 of the rotary press or a diameter enlarged by an amount of applied tension (an amount of elongation percentage). The drum roller 54 is arranged so as to obtain a turning force from the driving shaft 30 of the rotationally driving section 24 which is disposed at the side of the printing unit 18 in order to rotationally drive the plate cylinder 22. The driving shaft 30 acts as an input shaft to a first gearbox 64 provided in the sheeter 40 extending from the printing unit 18, and said drum roller 54 can be rotationally driven through a speed change mechanism which is arranged so as to attain the same rotating-speed change percentage transmission ratio as the plate cylinder 22. The rotating-speed change percentage depends on a gear ratio of said gear box 64 and a turning ratio of a belt 70 which is wound between a first output shaft of the gear box 64 and a rotary shaft 68 of the drum roller 68. Thus, the drum roller 54 can be synchronously driven with the plate cylinder 22 at the same time rotating speed as that of the cylinder 22, and consequently, the speed introducing the running sheet 36 to the cutting section 44 corresponds to the printing speed of the rotary press. In addition, said drum roller 54 is designed in such a way that it is detachable from the rotary axis 68. As shown in Figure 4, tapered fitting portions 72 are provided on both ends of the drum roller 54 to detach from the rotary axis 68, which is coupled to the drum roller 54 by fitting a key, spline, or serration into the tapered fitting portion, and a turning force can be transmitted. Those means are provided so as to allow another drum roller 54 having the same diameter as that of another plate cylinder 22 to be exchanged after having exchanged the existing drum roller 54 and plate cylinder 22. The turning force transmitted from the driving shaft 30 of the rotationally driving section 24 in the printing press, also is used as a turning force of the drawing roller 60 and flying knife 62. As shown in the enlarged diagram of Figure 4, turning force is transmitted to the drawing roller 60 by winding a belt 75 between an input axis 74 of a second gear box 73 and the first output shaft 66 of the gear box 64, and transmitted to the flying knife 62 by winding a belt 78 between a shaft of the flying knife 62 and a second output axis 76 of the first gear box 64. In this case, a non-stage transmission mechanism is built in said second gear box 73, which permits the rotating speed of the drawing roller 60 to be automatically regulated so as to be synchronous with the speed of the running sheet 36 fed from the related drum roller 54, accompanied by exchange of the drum roller 54. This mechanism may be a known transmission mechanism which is programmed to change a varying speed relating to changing a size of the drum roller 54. The printed sheet which is cut at the predetermined length in the sheet cutting section 44, is sent to the following sheet discharging section 46, which consists of an upper high-speed tape 80, a lower high-speed tape 82, and a low-speed tape 84, and these sheets are piled on an elevating forklift 86 of the piling section 48 provided in the final stage. In the on-line sheeter 40 that is so arranged, the drum roller 54 which has the same diameter as that of plate cylinder 22 of the printing unit 18 or a diameter enlarged by the amount of tension applied to the sheet, is mounted on the rotary shaft 68. When starting the printing system, the running printed sheet 40 which is printed through the plate cylinder 22 in the rotary press is introduced to the sheet introducing guide section 42, and passes between the drum roller 54 and the nip roller 56 through the guide roller 50 and 52.The drum roller 54 is rotated by the rotary shaft 30 of the rotationally driving section 24 which acts as a rotationally driving axis, and its speed-change percentage is set to be equal to a speed-change percentage of the plate cylinder 22, therefore, the running sheet 36 supplied in the sheeter 40 can be fed to the drawing roller 60 at the feeding speed which is synchronous with the feeding speed of the running printed sheet 36 in the printing unit 18. When exchanging a plate cylinder to change a printing size, the existing drum roller 54 is exchanged with another roller 54 having the same diameter but enlarged by the amount of a sheet elongation percentage, simultaneous with exchanging. Thereby, even if the plate cylinder 22 is exchanged,the feeding speed in the sheeter 40 can be always synchronized with that of the printing unit 18, thus, without complicated adjusting between the rotary press and the sheeter 40 for synchronizing them, the synchronization can be attained. In the sheeter 40, the drum roller 54 has the same diameter as the plate cylinder 22, and feeds the running printed sheet continually supplied from the printing unit 18 to the cutting section 44 by biting it between the roller 54 itself and the nip roller 56 rotationally contacting with each other. Since the drum roller 54 synchronously rotates in conjunction with the rotary shaft 30 and is exchanged with another drum roller 54 having the same diameter as that of another plate cylinder 22 at the same time whenever the plate cylinder 22, changing a length of cut can be carried out by exchanging the drum roller 54 simultaneously. Accordingly, a length of cut can be automatically adjusted only by exchanging the drum roller 54, and such sheeter 40 can be employed on-line. Especially, a label printing sheet which can be discharged as a section of print due to undetermined size, need not be cut off-line after rewinding with a rewinder once, therefore the working effectiveness can be significantly improved. In addition to the changing a length of cut which the above embodiment has been described as to, the concerned sheeter 40 is able to effect an accurate cutting process even though it is used as a sheeter whose length of cut is fixed to one length. That is, the drum roller 54 having the same diameter as that of the plate cylinder 22 is provided in the sheet introducing guide section 42, which section is arranged so as to synchronously drive the drum roller 54 by the rotary shaft 30 of the plate cylinder 22 in rotation. Thereby, the same variation of rotating speed occurs in the drum roller 54 even if a rotating speed of the plate cylinder 22 varies, a rotating speed of the drawing roller 60 which has the same driving source can be perfectly synchronized. Accordingly, in comparision with the cases where only a drawing roller is manually or automatically controlled as in a conventional system, accuracy of synchronization significantly increases, a variation of a length of cutting a printed sheet very reduces, then a sheet which is cut with higher accuracy can be obtained.

Claims: An on-line sheeter (40) of a printing system for cutting a running printed sheet (36) fed from a printing unit (18) having a rotationally driven plate cylinder (22) in sheets of a predetermined length, comprising: a sheet introducing guide section (42, 50, 52, 54) for feeding the running printed sheet (36) discharged from the printing unit (18) via a drawing roller (60) into a cutting section (44), the cutting section (44) having a cutting means for cutting the running printed sheet in sheets of predetermined length, characterized in that a drum roller (54) is mounted on the sheet introducing guide section (42), the drum roller (54) having the same diameter as the plate cylinder (22) or a diameter enlarged by the amount of elongation of the running printed sheet (36), the drum roller (54) and the plate cylinder (22) rotating synchronously, the drum roller (54) and the plate cylinder (22) each being exchangeably mounted in the printing system, and a nip roller (56) rotationally contacts the drum roller (54) via the running printed sheet passing therebetween and nips the running printed sheet. An on-line sheeter of a printing system according to claim 1, wherein the drum roller (54) is able to synchronously rotate by obtaining a turning force directly from a rotatable driving shaft (30) of the plate cylinder (22). An on-line sheeter of a printing system according to one of claims 1 or 2, wherein the nip roller (56) can touch and is separable from the drum roller (54). An on-line sheeter of a printing system according to one of claims 1 to 3, characterized in that the cutting means comprises a flying knife (62) which is arranged downstream the drum roller (54) and the nip roller (56). A method of changing the cut length in a sheeter for changing the length of sheets into which a running printed sheet (36) is cut, wherein the running printed sheet (36) is fed from a printing unit (18) having a driven plate cylinder (22) to a sheet introducing guide section (42, 50, 52, 54) and further via a drawing roller (60) to a cutting section (44), characterized in that a drum roller (54) of the sheet introducing guide section feeds the running printed sheet to the cutting section (44), contacts a nip roller (56) via the running printed sheet passing therebetween and is rotated synchronously by a shaft (30) for driving a plate cylinder (22) of the printing unit (18), wherein the cut length is changed by exchanging the drum roller (54) and the plate cylinder (22) at the same time, the diameter of a replacement drum roller (54) being the same as that of the replacement plate cylinder (22) or enlarged by the elongation of the running printed sheet (36).

Inventors: MATSMOTO KIYOSHI, OKADA TAKASHI, MATSMOTO, KIYOSHI, OKADA, TAKASHI, Matsmoto, Kiyoshi, c/o Nikka Kabushiki Kaisha, Okada, Takashi, c/o Niimura Insatsu Kabushiki K.
Applicants: NIIMURA INSATSU KABUSHIKI KAIS, NIKKA KK, NIIMURA INSATSU KABUSHIKI KAISHA, NIKKA KABUSHIKI KAISHA
Application year: 1993
Main classification: B41F13
IPC codes: B26D5, B41F13