Packaging container production equipment and packaging container production method - I

Abstract: The action pattern of the web feeding amount by the lug folding flaps is made optimal in compliance with deviations of detection marks such as specified printing patterns on the printing surface on web W from the reference values when they are detected, and the pressing force applied onto web W by dancer roller 9 is escalationally (stepwise) or continuously adjusted according to the action patterns. Therefore, comparison with the conventional examples, it is possible to widen the corrective range of web feeding amount. Thus, the range for unevenness due to printing errors on web W can be widened, and it is possible to operate the equipment without making a stop. Furthermore, it is possible to produce packaging containers with printing patterns applied onto appointed positions, and faulty products are eliminated.

Description: Technical Field The present invention relates to packaging container producing equipment and a packaging container producing method, in particular to packaging container producing equipment and a packaging container producing method of reforming sheet-like web to tubular web and filling said tubular web with contents such as fluid food. Background Art In packaging container producing equipment for producing packaging containers, into which a content is filled, from sheet-like web, rolled sheet-like web W of rewinder 1, which is wound to be roll-like as shown in FIG. 1, is wound back by a windback device, the wound-back sheet-like web W is transferred by web feeding roller 10 and is sent to tube forming device 3 via tension pressing device 2 consisting of a dancer roller (rocking roller) 9, which gives tension to the abovementioned web W at all times, and guide roller 11, wherein the sheet-like web W is reformed to be tubular web W while being formed by forming rollers 14 (only one stage is illustrated in FIG. 1) provided to be multi-staged, and the edges overlapped in the lengthwise direction of the tubular web W are sealed (longitudinally sealed) in the longitudinal direction. Furthermore, after a part of web W is sealed (cross-sealed) in the direction orthogonal to the lengthwise direction of web W, a content is filled into a tubular web W located in the upstream side of the cross-sealed part, and after cross sealing is further carried out at a size equivalent to one container at the abovementioned web, said cross sealed part is cut off, thereby a hexahedral packaging container is produced, in which the content is filled. The tube forming device 3 is provided with a filling pipe 5 to fill a tube with a content such as fluid food, etc. and is provided with a pair of seal jaws 7 (only one jaw 7 is illustrated in FIG.1, two pairs of cross seal jaws 7 are provided so as to vertically move) in order to seal the tubular web W from both the sides of the tubular web W via a drive mechanism (not illustrated) from the main shaft 6 of the packaging container producing equipment. A pair of cross seal jaws 7 move downwards while pulling downward the tubular web W being transferred downwards. After the seal jaws 7 falls down to an appointed distance, they release the sealing state of web W to cancel the downward transfer force of the tubular web W and move in such a direction of separating each other. Then, the seal jaws 7 are elevated to an appointed distance and repeat a sealing action of the tubular web W again. At this time, as shown in a detailed view (only one of the pair is illustrated in this drawing) of the cross seal jaws 7 of FIG.3, the abovementioned cross seal jaws 7 are provided with jaws 7b attached to a horizontal bar 7a, and web is nipped between a pair of jaws 7b to cause a cross sealing to be executed. Furthermore, lug folding flaps 7c rotating in the direction of the arrow A are attached to one of the cross seal jaws 7, wherein while web W is nipped between a pair of jaws 7b, the abovementioned lug folding flap 7c is able to fold lugs Wb formed at the web W. On the other hand, specified printing patterns and detection marks a (See FIG.4) such as a straw port for registering positions are provided at appointed intervals on the web W. As using the position of the abovementioned detection mark a as reference, it is necessary to adjust the feeding amount of web W (this is called "mark registration") in packaging container producing equipment so that detection marks a of printing surface of every packaging container C come to an appointed position. However, since errors in positioning of patterns and straw port when printing on sheet-like web and changes of the feeding amount of web W due to defective rotations of rollers in the packaging container producing equipment are unavoidable, it is necessary to register the abovementioned marks at all times while the packaging container producing equipment is in operation. If the feeding amount enters such a state where it can not be adjusted by registering the abovementioned marks, there are cases where packaging containers C which are the final formed products can not be formed to their object shape. Since ever, the mark registration is carried out by combination of (1) a method of adjusting the folding amount of web W in its transfer direction and (2) a method of adjusting the degree of tension applied to web W being transferred. (1) Method of adjusting the folding amount of web W in its transfer direction (See FIG. 11) The feeding amount of web W in the transfer direction is classified into the following two stages of action, wherein the first action is to adjust the feeding amount of web W in the transfer direction by a pulling intensity of web W, and the second action is to adjust the folding angle of lug part formed on web W. By combining these methods, the web W is transferred in the web transfer direction. That is, mechanical feeding action of web W in the transfer direction consists of the following two actions shown in FIG. 11. 1 ○ By the sealing part of web W being nipped at both sides by a pair of cross seal jaws 7, the mechanical feeding action is carried out by pulling the web W equivalently to the moving amount of the cross seal jaws 7 in the web transfer direction (See FIG. 11(a)). The drive of a pair of cross seal jaws 7 consisting of two sets is repeated as shown by the arrow R in FIG. 11, wherein a pair of cross seal jaws 7 consisting of two sets repeat this action alternately, web W can be continuously transferred. 2 ○ The shape of web W taken along the line A-A in FIG. 11(a) is as shown in FIG. 11(b), and the lug part web Wb (See FIG. 12) is folded, as shown in FIG. 11 (c) , from both sides of tubular web W in the right angle direction with respect to the cross seal part Wa formed by the abovementioned action (i). The abovementioned actions 1 ○ and 2 ○ are basically for applying cross sealing to tubular web W, folding a lug part formed at the cross sealed part and finally forming a hexahedral body. However, by adjusting the folding angle of the lug folding flaps 7c, it is possible to adjust the feeding amount of web W. ( 2 ) Method of adjusting the degree of tension applied to web W being transferred In order to accurately move web W only an appointed distance without fail by the method of adjusting the web feeding amount based on adjustment of the folding angle by the lug folding flaps 7c of the abovementioned action (1), it is necessary give adequate fixed tension to web W by tension pressing device 2 (FIG. 1). For example, if the tension of web W is too intensive, a mechanical slip occurs between web W and its feeding members, thereby causing the movemental amount of web W to be decreased. To the contrary, if the web tension is too weak, the web is slackened to cause the web W to be transferred beyond the necessity. Thus, appointed tension is given to web W so that the movemental amount of web W being transferred is not too weak or too intensive. By combination of this method (2) and the abovementioned method (1), the mark registration is carried out. A corrective action of the feeding amount is carried out by the lug folding flaps 7c while applying appointed tension to web for a slight change (for example, 1% of the prescribed value) of the feeding amount of web W. However, the appointed tension control by a tension pressing device was carried out by only the pressing force in the direction of gravity due to the self weight of the dancer roller 9 shown in Figure. 1. However, if the printing patterns of packaging containers which are the final products slips from their adequate positions, the containers is worthless. Therefore, it is necessary that a change (error) of the feeding amount of web W, for example, the average error of each time for 100 pitches of web feeding action equivalent to one packaging container C is less than an appointed value (for example, 0.5mm or less) and a change (error) of the feeding amount of web per pitch of the web feeding action equivalent to one packaging container C does not exceed an appointed value (for example 1.5mm). Furthermore, the more the consumption of roll-like web W becomes, the more frequently occurs a case where a slip of the detection marks a correctable by the abovementioned method (1) of adjusting the folding amount of web in the transfer direction exceeds the permissible range of correction of the mark registration, wherein it becomes impossible to correct the feeding amount of web W. US-A-4081944 describes an example of a prior art packaging container production equipment for forming tubular web from sheet-like web and producing hexahedral packaging containers in accordance with the foregoing description. Thus, in prior arts, since the adjustment allowance of the feeding amount of web W is narrow, there was a problem by which it was difficult to adjust the feeding amount of web W with the machine continuously operating. It is an object of the invention to eliminate the deficits of the prior arts. It is furthermore an object of the invention to increase the correctable allowance of error of mark registration of detection marks such as printing patterns on web W. Furthermore, it is another object of the invention to widen the corrective action range of web feeding amount, so that products do not become defective even though a change (error) of the feeding amount of web W is larger than before. Furthermore, it is still another object of the invention to provide equipment and a method for producing packaging containers having high quality by increasing the adjustment range of the feeding amount of web W using, as a reference, the positions of detection marks, which will be signs on the web W, as references. Disclosure of the Inventions The abovementioned themes and objects of the invention are solved by the following construction. That is, packaging container production equipment for forming tubular web from sheet-like web and producing hexahedral packaging containers, comprises: a web tension pressing means provided with a rocking arm and a rocking roller secured at the tip end thereof, which transfers sheet-like web while pressing the sheet-like web by the rocking roller; a web tension pressing force setting means for setting the pressing force of said tension pressing means; a sealing member for forming sealing parts at tubular web by pressing both sides of the tubular web while folding both the sides of said tubular web in the direction orthogonal to the lengthwise direction of the tubular web obtained from sheet-like web; a mark detecting means for detecting that specified detection marks which will be targets on the web are fed onto the points of detection which will be the specified references established in advance; a folding amount setting means of said sealing member, by which the folding amount of the sealing member are set to a plurality of stages; a folding amount controlling means of said sealing member, for selecting an optimal action from a plurality of stages of set values of said folding amount setting means of said sealing member, in response to the deviation between a timing when said mark detecting means detects a specified detection mark on web at a point of detection which will be a specified reference, and a timing when a specified printing detection mark is detected, which will be a reference established in advance at said specified point of detection; and a web tension pressing force controlling means for escalationally (stepwise) r continuously adjusting the pressing force set value of said web tension pressing force setting means to an optimal value in response to actions selected by the folding amount controlling means of the sealing member. Furthermore, the themes and objects of the inventions are solved by the following construction. A packaging container production method for forming tubular web from sheet-like web and producing hexahedral packaging containers from the abovementioned tubular sheet-like web, comprises the steps of: transferring sheet-like web while controlling a tension pressing force to an optimal value with respect to the sheet-like web; forming tubular web from the sheet-like web being transferred; nipping both the sides of the tubular web in the direction orthogonal to the lengthwise direction said tubular web and forming a sealing part at the tubular web by folding the same; selecting and executing, from a plurality of actions established in advance, an action of the folding amount of said both sides of web in compliance with the deviation between the timing when a specified detection mark, which will be the target on the web, is sent to the point of detection which is a specified reference established in advance and the timing when a specified detection mark, which will be the reference established in advance at said specified point, is detected; and controlling the tension pressing force for said sheet-like web so as to become an optimal value in compliance with said selected action. A sealing member according to the invention is composed of a pair of the first sealing member for sealing the side opposed to the direction orthogonal to the lengthwise direction of tubular web and the second sealing member for folding a lug of web formed by said first sealing member, wherein the folding amount setting means of the sealing member is constructed so as to take a set value which ensures a usual feeding action by which the folding amount of the second sealing member is set at the first appointed angle and a corrective feeding action by which the folding amount of the second sealing member is set at the second appointed angle; and the folding amount controlling means of the sealing member selects a usual feeding action consisting of a specified feeding amount exceeding the reference feeding amount and a corrective feeding action consisting of a specified set feeding amount below the reference feeding amount in compliance with the timing when a specified detection mark which will be the target on web is detected by the mark detection means of web, and is able to control the feeding amount of web by the sealing members. And, the web tension pressing force controlling means may be provided with a pressing force changer mechanism which changes the set value of the web tension pressing force setting means to a more intensive set value when the corrective feeding actions by the second sealing means are carried out more frequently than an appointed frequency, and changes the set value thereof to a weaker set value when the corrective feeding actions are carried out less frequently than an appointed frequency. A tension pressing force setting means used in the abovementioned packaging container producing equipment according to the invention employs a pneumatic cylinder or a hydraulic cylinder equipped with a pressure changer feature, which generates a plurality of stages of pressure levels to press the rocking roller (dancer roller), and an electro-pneumatic proportional valve which continuously (stagelessly) generates pressure proportionate to the size of electric signals. Thus, according to the invention, since the pressing force given to web W in the tension pressing device and/or the folding amount of web W by a pair of sealing members in the tube forming device are controlled in compliance with the deviation of the detected value of detection mark (specified printing patterns or straw port) on the web W from the reference value, the feeding amount of web W can be adjusted. It is preferable that the deviation of the detected value of specified detection marks on web W from the reference values is'based on the deviation between the reference set value of the rotating angle or number of times of rotation of the main shaft of the packaging container producing equipment and the detected value of the detection marks. This is because that the drive amount of almost all the drive parts of the packaging container producing equipment such as cross seal jaws, container forming conveyor, etc. depend upon the value of the rotating angle or the number of times of rotations of the main shaft. However, not depending the rotating angle and the number of times of rotations of the main shaft, the deviation of the detected value of the abovementioned specified detection marks from the reference value may be measured on the basis of the drive amount of the other drive parts. A controlling action of the web feeding amount by sealing members (for example, lug folding flaps) consists of the abovementioned usual feeding action and corrective feeding action and is to control a combining action of the usual feeding action and corrective feeding action and to control the pressure (pressing force) applied to web W by a rocking roller (dancer roller), wherein the corrective range thereof can be enlarged in comparison with the corrective range of web feeding amount by the conventional method without using an adjusting means of web tension pressing force. The invention is further provided with, in addition to the abovementioned adjustment method and equipment of the feeding amount of web W, position detecting means of the upper limit and lower limit positions of a dancer roller rocking in the vertical direction and a construction capable of changing the sheet-like web to a high-speed set value and low-speed set value by the feeding roller by detecting the upper limit and lower limit positions of the dancer roller of each of the abovementioned position detection means, wherein it is possible to further widen the adjustment width of the web feeding amount. Thus, with the invention, it is possible to increase the corrective range of web W feeding amount in comparison with the conventional corrective range of the web W feeding amount. Therefore, the treatment range regarding unevenness such as printing deviations on web W can be further improved to ensure that continuous operation is enabled without stopping the machine. Furthermore, it is possible to produce packaging containers on which printing patterns are correctly placed at appointed points and accordingly possible to decrease the number of faulty products. Brief Description of the Drawings FIG.1 is a sketch of equipment for producing packaging containers, in which a content is filled, from sheet-like web according to a preferred embodiment of the invention, FIG.2 is a rough perspective view of a tension pressing device of the packaging container producing equipment of FIG. 1, FIG. 3a is a perspective view of cross seal jaw of the packaging container producing equipment of FIG. 1, and FIG. 3b is a top plan view thereof, FIG.4 is a view explaining a mechanism of carrying out mark registration by adjustment of the web folding amount by cross seal jaw of the packaging container producing equipment of FIG. 1, FIG.5 is a view explaining a flap drive section of FIG. 4, FIG. 6 is a block diagram of a control device of a tension pressing force of the packaging container producing equipment of FIG.1 and of web folding amount by the cross seal jaw, FIG.7 is a sketch of tension pressing device and cross seal jaw of the packaging container producing equipment of FIG. 1, FIG.8a is a view explaining a usual feeding action of the cross seal jaw of the packaging container producing equipment of FIG.1, and FIG.8b is also a view explaining a corrective feeding action thereof, FIG.9 is a pattern view showing movements consisting of a combination of the usual feeding action and corrective feeding action of FIG.8, FIG.10 is a flow chart of combined movements of the usual feeding action and corrective feeding action of the cross seal jaw of the packaging container producing equipment of FIG. 1, FIG. 11a is an operation view of the cross seal jaw of packaging container producing equipment, and FIG. 11b and FIG.11c are perspective views taken along the line A-A in FIG. 11a, and FIG.12 is a perspective view of the cross sealing part of tubular web. Description of the Preferred Embodiments A description is given of a preferred embodiment of the invention. Packaging container producing equipment according to a preferred embodiment of the invention is composed of the same construction as the packaging container producing equipment described in FIG. 1, excepting the major parts. FIG. 2 is a sketch of a tension pressing device of web W being transferred, which is not illustrated in the packaging container producing equipment of FIG. 1, FIG. 3(a) is an enlarged perspective view of web cross seal jaws 7, and FIG. 3 (b) is a top view thereof. FIG. 4 is a view of a drive mechanism of lug folding flaps based on detection of specified printing patterns or specified detection marks such as a straw port on web W, FIG. 5 is a sketch of the major parts of drive of lug folding flaps, and FIG. 7 is an explanatory view of a printing error absorbing (mark registration) mechanism. The packaging container producing equipment shown in FIG. 1 is as described above, wherein tubular web W is transferred while being pulled by a pair of cross seal jaws 7 during a downward movement thereof, in the process of pressing said web W by a pair of cross jaws 7 from the direction orthogonal to the lengthwise direction of the tubular web W. At this time, while web Wa (FIG. 12) is being nipped between a pair of jaws 7b of the cross seal jaws 7, lug folding flaps 7c folds in the lugs Wb formed at web W. Therefore, tubular web W is transferred downward by movement and folding while the web W is nipped by a pair of cross seal jaws 7 in the tube forming device 3. However, after the pair of cross seal jaws 7 carry out feeding of web W for an appointed distance while going downward, they repeat an elevating movement. In practice, a pair of cross seal jaws 7 are provided two sets as shown in FIG. 7, wherein after they feed web W downward for an appointed distance, they repeat a returning movement to the original position as shown at the arrow R in FIG. 7. On the other hand, the tension pressing device 2 is to control the feed rate and feeding amount of web W inside the packaging container producing equipment or to apply tension to the web W at all times since the formability is worsened and the web feeding amount becomes unstable unless tension is applied to the web when tubular web in which a content is filled is formed to be square-column-like web W by forming members (not illustrated). FIG. 2 is a perspective view of tension pressing device 2. The tension pressing device 2 is provided with a dancer roller (rocking roller) 9 which is disposed between a feeding roller 10 driven by drive means 8 having a clutch to send out web W in the transfer direction and a guide roller 11 and is rockable in the direction almost orthogonal to the web transfer direction; a pair of rocking arms 12 which have the abovementioned dancer roller at its tip end and causes the dancer roller 9 to rock in the direction almost orthogonal to the web transfer direction; a rotating shaft 13 secured at the base of the abovementioned pair of rocking arms 12, which transmits a drive force to the rocking arms 12; and a pneumatic cylinder 16 (a hydraulic cylinder or a motor other than a pneumatic cylinder may be acceptable) for driving said rotating shaft 13 via a lever 15. The pneumatic cylinder 16 is provided with a control valve 31 for controlling the air pressure in multistage in compliance with the timings of detecting a detection mark a (FIG.4). An electro-pneumatic proportional valve, etc. which is able to continuously adjust the tension pressing force of web may be employed. Furthermore, a pressing roller 17 which transmits a transfer force to web being transferred between the feeding roller 10 and the abovementioned feeding roller 10 is secured at the position opposite the feeding roller 10. As shown in FIG. 2, although the rotating shaft (not illustrated) of the feeding roller 10 and guide roller 11 is supported at the wall of germfree chamber 18, the dancer roller 9 is not supported at said wall. The dancer roller 9 is able to move in the direction almost orthogonal to the feeding direction of web W with respect to rocking of the rocking arm 12. However, in order to solve a slip such as a printing error on web W, as explained above, there are two methods, that is, (1) a method of adjusting the folding amount of web W in the transfer direction, and (2) a method of adjusting the tension pressing force onto web W by the tension pressing device 2. (1) Method of adjusting the folding amount of web W in the transfer direction In this embodiment, this method employs a method of changing the folding angle of lug folding flaps 7c (provided at only one cross seal jaw 7 of a pair of cross seal jaws 7) of the cross seal jaw 7. A detector 19 for detection mark a such as a specified printing pattern, straw port, etc. is installed, as shown in FIG. 4, at a specified point established in advance in packaging container producing equipment. Data signals detecting a detection mark a of web W of the abovementioned detector 19 and cam rotation angle signals of an encoder 22 for detecting the rotation angle of the main shaft 6 to which a cross seal jaw drive cam 24 is attached are inputted into a control device 23. The rotation angle of shaft 6 of the cam 24, which is secured at the point when the data signal of the abovementioned detection mark a is read, is regarded as a detection angle of the detection mark a in the abovementioned control device 23, and a deviation between the detection angle of the abovementioned detection mark a and the reference angle established in advance are obtained, wherein a value responsive to the deviation is outputted, via a solenoid valve 25, to the pneumatic cylinder 26 for adjusting the folding amount of lug folding flaps 7c (FIG. 3) of the cross seal jaws 7. As shown in FIG. 5, lug folding cam 27 is able to take positions 1 ○ and 2 ○ in FIG.5 by the pneumatic cylinder 26. Since a roller 28 moves on the cam surface when the lug folding cam 27 is at the position 1 ○, the lug folding flap 7c carries out a corrective action of folding to the position shown in FIG. 8(b), and since the roller 28 moves on the cam surface when the lug folding cam 27 is at the position 2 ○, the lug folding flaps 7c carries out a usual feeding action of folding to the position shown in FIG. 8(a). With reference to FIG. 6, a description is given of a control device which is to adjust the folding amount of the abovementioned cross seal jaw 7 into the web W transfer direction by the lug folding flaps 7c. Data of web W detection mark a, which is detected by the detector 19, is inputted into main shaft rotation angle judging circuit 33 of the control device 23. Furthermore, the rotation angle of the main shaft 6 detected by the encoder 22 is inputted into the main shaft rotation angle judging circuit 33. The main shaft rotation angle judging circuit 33 regards the rotation angle of the main shaft, which is secured at the point of time when the data of detection mark a read by the detector 19 is inputted, as a mark detection angle. Furthermore, the data of the detector 19 is also inputted into a production control circuit 35, which is used as data of production control. The detection angle of the main shaft 6 is inputted into a subtracter 36, and since the reference angle (the rotation angle which will become the reference, established in advance, of the main shaft 6, which is detected by the encoder 22 when a detection mark a of web W passes at the detector 19) of the main shaft 6 is inputted into the subtracter 36, the deviation between the detection angle and reference angle is obtained, wherein the deviation value is inputted into a corrective value calculation circuit 38. In the corrective value calculation circuit 38, a corrective value corresponding to the abovementioned deviation value is obtained, and an electric signal corresponding to the corrective value thus obtained is outputted from the control device 23 to a solenoid valve 25. Here, the pneumatic cylinder 26 (FIG. 4) is driven, wherein the lug folding flap 7c carries out a usual feeding action or a corrective feeding action in order to obtain an adequate feeding amount of web W. The lug folding angle of web W of the lug folding flaps 7c is established fromadeviation between the detection angle of the detection mark a by the detector 19 and the reference in such a manner that a usual feeding action which produces a web feeding amount obtained by adding only 0.5mm to the reference feeding amount is employed until a detection value equivalent to the value obtained by adding only 1.5mm to the reference feeding amount is obtained as for the web feeding amount, and as the detection value equivalent to a value obtained by adding only 1. 5mm to the reference feeding amount is obtained as for the web feeding amount, a corrective feeding action which produces a web feeding amount obtained by subtracting only 1.0mm from the reference feeding amount is employed. In FIG. 8, FIG. 8 (a) is a view explaining a usual feeding action of web W and FIG. 8(b) is another view explaining a corrective feeding amount of web W. In the usual feeding action of web W in FIG. 8(a), web W is fed at the initial set value equivalent to the web feeding amount obtained by adding only 0. 5mm to the reference feeding amount (the feeding amount which becomes a reference on design) at a folding angle A° of the lug folding flaps 7c. Web feeding amount in the usual feeding action = Reference feeding amount + 0.5mm. Furthermore, the folding angle of the lug folding flaps 7c is changed to angle B° in the corrective feeding action of web W shown in FIG. 8(b) to secure the feeding amount obtained by subtracting only 1.0mm from the abovementioned reference feeding amount. Web feeding amount in the corrective feeding action = Reference feeding amount - 1.0mm As regards the abovementioned web W feeding amounts [-1.0mm] or [+0.5mm], the detailed figures are used for only making the explanation more understandable. That is, the usual feeding action and corrective feeding action of the invention are not limited to these figures. Conventionally, the feeding control of web W was controlled by only the abovementioned usual feeding action and corrective feeding action of the lug folding flaps 7c. For example, where it is assumed that there is no printing error (no slip of the detection mark a) of web W, and there is nothing abnormal in the feeding amount of the feeding roller 10, guide roller 11, etc., as shown in FIG. 9 (a), the folding angle of the lug folding flaps 7c is changed to angle B°, as shown in FIG. 8(b), and the action is changed to a corrective feeding action at the point of time (after the usual feeding action is performed two times) when web W is excessively fed 0.5mm each by the abovementioned usual feeding amount made by the lug folding flaps 7c and web W is excessively fed 1. 5mm which is the allowance of slip from the reference feeding amount. Web W, the slip of which became 0.5mm from the reference feeding amount by the corrective feeding action, is caused to enter the usual feeding action again. In a case where there is no slip of the detection mark a such as a printing error of web W and there is nothing abnormal in the feeding amount of feeding roller 10, guide roller 11, etc., the abovementioned corrective feeding amount is carried out once every three feeding actions (See FIG. 9 (a)). However, herein, since web W is excessively fed 0.5mm per usual feeding action if a slip of the detection mark a of web W is, for example, +0.5mm, the slip from the reference feeding amount in total becomes 1.5mm per usual feeding action, wherein the feeding is changed to a corrective feeding action after the usual feeding action is performed once. Therefore, the corrective feeding action is executed once every two feeding actions as shown in FIG. 9 (b). If the control device 23 judges that, in the usual feeding action, a slip from the reference feeding amount became 1.5mm, the action is changed to the corrective feeding action. Furthermore, since web W is excessively fed 0.5mm in the usual feeding action if a slip of the detection mark a of web W is, for example, -0.25mm each, the feeding action is separated 0.25mm each from the reference position in one usual feeding action in total, and at the point of time when the slip from the reference feeding amount becomes 1.5mm, the action is changed to a corrective feeding action. Therefore, as shown in FIG. 9(c), the corrective feeding action is executed once every five feeding actions. (2) Method of adjusting the degree of tension applied onto web W being transferred In order to accurately cause web W to move an appointed distance without fail by the method (1) of adjusting the web feeding amount by adjustment of the folding angle by the lug folding flaps 7c, it is necessary to give adequate fixed tension to web W by the tension pressing device 2 (FIG. 1). If the abovementioned markregistration is carried out by only a combination of the method (2) with the method (1), there is the following cases which can not be solved, as described in the clause of "Themes to be solved in prior arts". That is, as regards a change (error) of the feeding amount of web W, it is necessary that, for example, the average error of each time for every 100 pitches of the web feeding action equivalent to one packaging container C is less than an appointed value (for example ±0.5mm), and a change (error) of the feeding amount of web W per pitch of the web feeding action equivalent to one packaging container C does not exceed an appointed value (for example ±1.5mm). However, the more the consumption of roll-like web W becomes, the more frequently a case occurs, where the feeding amount exceeds the allowance range of error of the mark registration of detection mark a, which is correctable by the method (1) of adjusting the folding amount of web W in the transfer direction by the cross seal jaws 7. For example, in three pattern examples shown in FIG. 9 (a) through FIG. 9 (c), if a slip of the detection mark a from the reference feeding amount, such as a printing error of web W, is +1.0mm per pitch of the abovementioned actions, the slip exceeds the allowance range of printing error at once, thereby causing faulty containers C to be produced. In some cases, packaging container producing equipment is unavoidably caused to come to a stop. Furthermore, if a slip of the detection mark a, such as a printing error of the abovementioned web W is continuously, for example, -0.5mm or more per pitch, the slip goes beyond the reference feeding amount line (See FIG. 9) equivalent to the reference feeding amount, the correction of the feeding amount of web W becomes impossible. Thus, since in prior arts the adjustment range of the feeding amount of web W is narrow, there is a problem by which it is difficult to adjust the feed amount of web W while continuously running the equipment. Therefore, in this preferred embodiment, the following construction is employed in order to increase the correctable allowance range of error of mark registration of detection mark a on web W. It is a method of escalationally controlling the tension pressing force of the dancer roller 9 in multistage with respect to web W by a tension pressing device 2, or a construction in which the tension pressing force is continuously controlled without any stage. In FIG. 2 and FIG. 7, a pneumatic cylinder 16 for driving a rocking arm rocking shaft is secured at the abovementioned rocking arm 12 having a dancer roller 9 at its tip end, and a control valve 31 consisting of an air pressure changing feature is provided at the pneumatic cylinder 16 so that air pressure can be generated in multistage, for example three stages (strong, medium and weak), wherein the air pressure of the pneumatic cylinder 16 for driving the rocking arm rocking shaft is changed in compliance with an action pattern selected by the folding amount controlling means to fluctuate the tension applied onto web W, thereby causing the feeding amount to be adjusted. A flow chart of FIG.10 shows a control method of the feeding amount of web W by web pressing force of the web tension pressing device 2 shown in FIG. 1, FIG. 2, etc. , and FIG.6 shows a control device 23 of the feeding amount of web W by web W pressing force of the web tension pressing device 2. After the air pressure of the cylinder 16 of the web tension pressing device 2 is set to the medium, the control valve 31 changes the web W pressing force of the tension pressing device 2 to "Strong", "Medium", "Weak" in compliance with a signal by which a mark slip frequency detecting circuit 41 outputs a frequency of corrective feeding actions on the basis of a signal coming from a corrective value calculation circuit 38 which outputs an instruction signal of a corrective feeding action and a usual feeding action by the lug folding flaps 7c. Thus, tension to press web W is changed by using a pneumatic cylinder 16 for driving the rocking arm rocking shaft of the tension pressing device 2, wherein by changing the initial value of the feeding amount of the web W feeding roller 10, a printing error of web W is absorbed, and the correctable range of the feeding amount of web W can be further widened than that of prior arts although the mechanical feeding amount of web W by a cross seal jaw 7 per time is fixed. For example, as the fundamental setting of an error absorbing (mark registration) mechanism of detection mark a is described in FIG. 9(a), it is assumed that there is nothing abnormal in the web feeding amount in the feeding roller 10, guide roller 11, etc., and a corrective feeding action (that is, an action of feeding web W by folding to angle B° by the folding flaps shown in FIG.8(b), and web W is less fed 1.0mm than the reference feeding amount) is carried out once after the usual feeding action of web W (an action of feeding a packaging material (web W) by folding to angle A° by the lug folding flaps 7c shown in FIG. 8(a), and web W is more fed 0.5mm than the reference feeding amount) is continuously carried out two times excessively 0.5mm each, and it is assumed that this state is called "a corrective feeding action has been carried out 1/3". Then, the tension applied to the dancer roller 9 is set to, for example 10N, and this state is regarded as fundamental setting. As the number of times of corrective feeding actions becomes 1/5 time halfway of executing continuous operation in this fundamental setting state, the control device 23 outputs a control signal, which sets the tension onto web W to be weak, to the control valve 31. That is, as the number of times of corrective feeding actions becomes 1/5, the web is expected to be excessively fed 0.5mm per time (per pitch) by the usual feeding action. Therefore, it means that the web W has not been fed equivalent to only the amount. In other words, it means that the pitch of detection mark a (See FIG. 4) of web W is longer than the prescribed pitch, and when being observed from the detection mark a side of web W, it means that the web W has not been fed only the prescribed amount. At this time, it is judged that the tension applied onto web W is strong, the control device 23 attempts to decrease the tension by the pneumatic cylinder 16 of the dancer roller 9. (For example, the fundamental setting 10N is decreased to 8N. As a result, even though the feeding amount of web W becomes great and a slip of the detection mark a of web W is, for example, -0. 25mm each for one pitch, a corrective feeding action of the pattern shown in FIG. 9(a) is carried out. Furthermore, similarly, if the number of times of corrective feeding actions becomes 1/2 times shown in FIG. 9(b) halfway of executing continuous operation in the fundamental setting state, the control device 23 outputs a control signal for setting the tension onto web W to "strong" to the control valve 31. That is, in this case, it is judged that the tension applied to web W (packaging material) is weak, the pneumatic cylinder 16 of the dancer roller 9 operates so as to increase the tension. Thereby, even though the printing error (slip of detection mark a) of web W is, for example, +0.5mm each, a correction feeding action of the pattern shown in FIG. 9(a) is carried out. Thus, the allowance range with respect to a printing error (slip of detection mark) of web W and abnormality of the web feeding amount by the feeding roller 10, guide roller 11, etc., can be further widened than prior arts. Next, a description is given of another embodiment which is constructed so that the tension fluctuation is decreased by securing the amount of accumulation of tension of web W by further actuating the feeding roller 10 in two stages, high speed and low speed, in a case where the tension pressing force of web is adjusted by a combination of usual feeding action and corrective feeding action of the web as described above. Since the web transfer channel is long, the web treads a complicated channel with its transfer direction changed many times, and the distance is long, a transfer force of the feeding roller 10 is used in addition to the web transfer force of cross seal jaw 7. However, it is remarkably difficult to completely coincide the web feedrate with the feedrate of the web feeding roller 10 by the cross seal jaw 7. Therefore, in order that the tension or feedrate of web at the tension pressing device 2 including the feeding roller 10 does not influence the web feedrate at the cross seal jaw 7, it is necessary to secure the amount of accumulation by the tension pressing device 2 consisting of web feeding roller 10, etc., so as to correspond to changes of the feedrate of web W due to the cross seal jaw 7. Therefore, it is constructed that a rocking type dancer roller 9 is provided at the feeding roller 10 part and the feeding roller 10 is able to be changed to high-speed operation and low-speed operation. Thereby, the tension applied onto web W can be controlled and kept to be fixed. When the feeding roller 10 is operated at a low speed, the dancer roller 9 is slowly elevated, and when the dancer roller 9 reaches the upper dead point, the feeding roller 10 is changed to a high-speed operation to cause the feeding amount of web to be increased. The dancer roller 9 is slowly lowered. When the dancer roller reaches the lower dead point, it is changed to a low-speed operation again to cause the feeding amount (feedrate) of web W per unit time to decreased. Then, the dancer roller 9 is elevated to cause the tension operating on the web W to be controlled and kept to be fixed. With reference to FIG. 2, a detailed description is given of a mechanism of controlling and keeping the tension operating onto web W to be fixed by changing the feeding roller 10 to high-speed or low-speed operation, wherein although the feeding roller 10 is driven by a drive means 8 having a clutch, the transfer force for web W is generated while the web W is being nipped between the feeding roller 10 and pressing roller 17. The pressing roller 17 is able to give a pressing force to the feeding roller 10 by using a fluid cylinder (not illustrated). Furthermore, rotation shaft 13 of the rocking arm 12 of the dancer roller 9 is provided at the wall of the germfree chamber 18 so as to penetrate the wall, and an operating arm 20 is fixed outside the wall of the corresponding chamber, wherein the operating arm 20 is elongated in a direction parallel to the rocking arm 12. The upper-limit position detector 21a and lower-limit position detector 21b are respectively provided at the outer wall side of the germfree chamber in the vicinity of the operating area at the tip end of the operating arm 20. Although the driving means 8 of the feeding roller 10 is operated at two stages, high speed and low speed, web W is intermittently sent in the process of forming it from tubular web W to hexahedral packaging containers C (FIG. 1). If it is assumed that it is continuously sent, the feeding amount per unit time is made a reference feeding amount. In this case, the operating speed of the driving means 8 is established so that the feeding amount of web W by the feeding roller 10 exceeds the reference feeding amount when the driving means 8 is operated at the high speed, and the feeding amount of web W by the feeding roller 10 becomes less than the reference feeding amount when the driving means 8 is operated at a low speed. Since the feeding amount of web W by the feeding roller exceeds the reference feeding amount if it is assumed that the driving means 8 is operated at the high speed, the web W is slackened, and the slackening thereof is gradually increased, and the dancer roller 9 is caused to go down by a pressing force of the pneumatic cylinder 16. Therefore,the rocking arm 12 rotates downward centering around its rotating shaft 13, and the operating arm 20 rotates in the same direction as that of the rocking arm 12 via its rotation shaft 13. In the meantime, as the tip end part of the operating arm 20 reaches the position opposite the lower limit position detector 21b, the same detector 21b detects this. At this time, the same detector 21b outputs a lower limit position signal, and the control device 23 changes the high speed operation of the driving means 8 to the lower speed operation on the basis of the output signal. If so, since the feeding amount of web W by the feeding roller 10 becomes less than the reference feeding amount this time,, the slackening of web W is gradually decreased, and the dancer roller 9 is elevated by being pulled by the web W. At this time, the operating arm 20 rotates in the reverse direction of the abovementioned direction, and as the tip end part comes to the position opposite to the upper limit position detector 21a, the same detector 21a outputs an upper limit position signal, wherein the driving means 8 is changed from the low speed operation to the high speed operation again. Thus, although the dancer roller 9 repeats vertical movements in a range that the upper limit position and lower limit position detectors 21a, 21b detect the operating arm 20, web W is given tension resulting from the pressing force by the pneumatic cylinder 16 of the dancer roller 9 in the meantime, wherein the web W is continuously sent at all times. Therefore, it is possible to keep the tension, applied onto the web W, fixed at all the times. Furthermore, since the upper limit and lower limit detectors 21a, 21b are disposed outside the germfree chamber 18, any trouble resulting from high temperature inside the germfree chamber 18 can be eliminated. As described above, according to the invention, in addition to operation of controlling the tension pressing force of web and operation of changing high speed/low speed operations of the driving means of web feeding roller in some cases, the allowance range of the corrective action of web feeding amount by the cross seal jaws 7 can be further widened than the prior arts, and if a change (error) of the feeding amount of web W is greater than in the conventional examples, no faulty products can be produced. Summary The action pattern of the web feeding amount by the lug folding flaps is made optimal in compliance with deviations of detection marks such as specified printing patterns on the printing surface on web W from the reference values when they are detected, and the pressing force applied onto web W by dancer roller 9 is escalationally (stepwise) or continuously adjusted according to the action patterns. Therefore, comparison with the conventional examples, it is possible to widen the corrective range of web feeding amount. Thus, the range for unevenness due to printing errors on web W can be widened, and it is possible to operate the equipment without making a stop. Furthermore, it is possible to produce packaging containers with printing patterns applied onto appointed positions, and faulty products are eliminated.

Claims: Packaging container production equipment for forming tubular web from sheet-like web and producing hexahedral packaging containers, comprising: a web tension pressing means (9-12) provided with a rocking arm (12) and a rocking roller 9 secured at the tip end thereof, which transfers sheet-like web (W) while pressing the sheet-like web (W) by the rocking roller (9); a web tension pressing force setting means (16, 31) for setting the pressing force of said tension pressing means (9-12); a sealing member (7) for forming sealing parts at tubular web by pressing both sides of the tubular web while folding both the sides of said tubular web in the direction orthogonal to the lengthwise direction of the tubular web obtained from sheet-like web; wherein said sealing member (7) is composed of a pair of the first sealing member (7a) for sealing the side opposed to the direction orthogonal to the lengthwise direction of tubular web and the second sealing member (7c) for folding a lug of web formed by said first sealing member (7a); a mark detecting means (19) for detecting that specified detection marks which will be targets on the web are fed onto the points of detection which will be the specified references established in advance; a folding amount setting means (25, 26) of said sealing member (7), by which the folding amount of the sealing member are set to a plurality of stages and which are constructed so as to take a set value which ensures a usual feeding action by which the folding amount of the second sealing member (7c) is set at the first appointed angle and a corrective feeding action by which the folding amount of the second sealing member (7c) is set at the second appointed angles; characterized by further comprising a folding amount controlling means (23) of said sealing member, for selecting an optimal action from a plurality of stages of set value based on a usual feeding action consisting of a specified feeding amount exceeding the reference feeding amount and a corrective feeding action consisting of a specified set feeding amount below the reference feeding amount, of said folding amount setting means (25, 26) of said sealing member (7), in response to the deviation between a timing when said mark detecting means (19) detects a specified detection mark on said web at a point of detection which will be a specified reference, and a timing when a specified printing detection mark is detected; and by further comprising a web tension pressing force controlling means (23) for escalationally (stepwise) or continuously adjusting the pressing force set value of web tension pressing force setting means to an optimal value in response to actions selected by the folding amount controlling means (23) of the sealing member (7). Packaging container production equipment as set forth in claim 1, wherein the web tension pressing force controlling means (23) is provided with a pressing force changer mechanism which changes the set value of the web tension pressing force setting means (16, 31) to a more intensive set value when the corrective feeding actions by the second sealing means (7c) are carried out more frequently than an appointed frequency, and changes the set value thereof to a weaker set value when the corrective feeding actions are carried out less frequently than an appointed frequency. Packaging container production equipment as set forth in claim 1 or claim 2, wherein the web tension pressing means (9-12) are provided with a rocking roller (9) rocking in the vertical direction, and a web feeding roller (10) having a drive force by which web is sent out in the transfer direction; and the web tension pressing force controlling means is provided with a position detecting means for detecting the upper-limit position and lower-limit position of the rocking roller, and a construction by which, on the basis of position detection of the upper-limit position and lower-limit position of the rocking roller of said position detecting means, the sheet-like web feeding amount by the web feeding roller is changed to a high-speed setting value and a low-speed setting value. A packaging container production method for forming tubular web from sheet-like web and producing hexahedral packaging containers, comprising the steps of: transferring sheet-like web while controlling a tension pressing force to an optimal value with respect to the sheet-like web; forming tubular web from the sheet-like web being transferred; nipping both the sides of the tubular web in the direction orthogonal to the lengthwise direction said tubular web and forming a sealing part at the tubular web by folding the same; characterized by the steps of selecting and executing, an optimal folding amount of said both sides of web in compliance with the deviation between the timing when a specified detection mark, which will be the target on the web, is sent to the point of detection which is a specified reference established in advance and the timing when a specified detection mark is detected, which will be the reference established in advance at said specified point, from a plurality of stages of set value based on a usual feeding action consisting of a specified feeding amount exceeding the reference feeding amount and a corrective feeding action consisting of a specified set feeding amount below the reference feeding amount; continuously or escalationally (stepwise) controlling the tension pressing force for said sheet-like web so as to become an optimal value in compliance with said selected action. A packaging container producing method as set forth in claim 4, wherein the control of web tension pressing force of sheet-like web is carried out by changing the set value of the web tension pressing force setting means to a more intensive set value when the corrective feeding actions by the second sealing means are carried out more frequently than an appointed frequency, and changing the set value thereof to a weaker set value when the corrective feeding actions are carried out less frequently than an appointed frequency. A packaging container producing method as set forth in claim 4 or 5, wherein the control of tension pressing force of sheet-like web is provided with a feature of changing the feeding amount of sheet-like web to a high-speed set value or a low-speed set value when the upper-limit position or the lower-limit position established in advance of an elevating member are detected. A packaging container obtained with the method of any one of Claims 4 to 6.

Inventors: FUJIMOTO AKIMASA, KATAYAMA HIROSHI, UEDA MICHIO, FUJIMOTO, AKIMASA, KATAYAMA, HIROSHI, UEDA, MICHIO, Fujimoto, Akimasa, c/o Shikoku Kakoki Co., Ltd., Katayama, Hiroshi, C/o Shikoku Kakoki Co., LTD., UEDA, MICHIO, C/O SHIKOKU KAKOKI CO., LTD.
Applicants: SHIKOKU KAKOKI CO LTD
Application year: 1998
Main classification: B31B37
IPC codes: B31B19, B65B9, B31B1