JP2005001114A - Apparatus for correcting printing pitch of plastic film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an apparatus for correcting the printing pitch of a plastic film so as not to require selection and adjustment to reduce a printing pitch correcting cost. <P>SOLUTION: Plastic films 1H and 1L are fed longitudinally and discontinuous break forming mechanisms 13H and 13L are provided to plastic film feed routes to form discontinuous breaks to the plastic films. Tension applying mechanisms 18H and 18L are provided to the plastic film feed routes to apply longitudinal tension to the plastic films and, when the longitudinal tension is applied to the plastic films, the plastic films are stretched by the lateral discontinuous breaks to correct the printing pitch of the plastic films. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial application fields]
The present invention relates to a printing pitch correction device for a plastic film having a printed pattern repeatedly printed with a substantially constant printing pitch.
[0002]
[Prior art and its problems]
Prior to this application, the applicant developed and proposed a printing pitch straightening device for plastic films. This is the case described in Japanese Patent Laid-Open No. 2003-48260 (Patent Document 1).
[0003]
In the apparatus of the publication, a plastic film is fed in the length direction. The plastic film has a printed pattern repeatedly printed with a substantially constant printing pitch. Further, a heater and a cradle are provided in the plastic film feed path, and the plastic film is sandwiched between the heater and the cradle, whereby the plastic film is pressurized and heated to be softened. Further, a tension applying mechanism is provided in the feeding path of the plastic film, a longitudinal tension is applied to the plastic film, and the plastic film is stretched at the heated portion. This corrects the printing pitch of the plastic film.
[0004]
However, in this case, a special heater must be provided, and the cost is high. Furthermore, it is not always easy to press and heat the plastic film with a heater and soften it. First, it is necessary to select the pressure, temperature and time accurately. Furthermore, the conditions differ depending on the plastic film, and it is necessary to change and adjust the pressure, temperature and time.
[0005]
[Patent Document 1]
JP 2003-48260 A
[0006]
OBJECT OF THE INVENTION
Therefore, the present invention has been made for the purpose of improving the plastic film printing pitch straightening device so that its cost is low and selection and adjustment are not required.
[0007]
[Structure of the invention]
According to this invention, a plastic film is sent in the length direction. The plastic film has a printed pattern repeatedly printed with a substantially constant printing pitch. Further, a discontinuous cut forming mechanism is provided in the plastic film feed path, a width direction discontinuous cut is formed in the plastic film, a tension applying mechanism is provided in the plastic film feed path, and the plastic film has a longitudinal tension. Added. Therefore, the plastic film is stretched by the longitudinal tension and the discontinuous cut in the width direction, thereby correcting the printing pitch of the plastic film.
[0008]
In a preferred embodiment, a pressure roller is used for the tensioning mechanism, the pressure roller is pressed against the plastic film, and a temporary tension is applied to the plastic film. When a temporary tension is applied, the plastic film is stretched by the discontinuous cuts in the width direction.
[0009]
Further, a plurality of optical sensors are provided in the plastic film feed path, and the printing position of the plastic film is detected by the optical sensors at different positions. Further, the control device is connected to the optical sensor, the discontinuous cut forming mechanism, and the tension applying mechanism, and the discontinuous cut forming mechanism and the tension applying mechanism are driven by the control device based on the detection signal of the optical sensor.
[0010]
In another embodiment, a dancer roller is used in the tensioning mechanism, the dancer roller is pressed against the plastic film, and continuous tension is applied to the plastic film. When the width direction cut is formed, the plastic film is stretched by continuous tension.
[0011]
Further, a plurality of optical sensors are provided in the plastic film feed path, and the printing position of the plastic film is detected by the optical sensors at different positions. Further, the control device is connected to the optical sensor and the discontinuous cut forming mechanism, and the discontinuous cut forming mechanism is driven by the control device based on the detection signal of the optical sensor.
[0012]
[Explanation of Examples]
Examples of the present invention will be described below.
[0013]
FIG. 1 shows an apparatus according to the present invention. This apparatus is a printing pitch correction apparatus for plastic films 1H and 1L, and is incorporated in a bag making machine. As in JP 2003-48260 A, the bag making machine uses two plastic films 1H and 1L. As shown in FIG. 2, the plastic films 1H and 1L have a substantially constant printing pitch. The printed pattern A is repeatedly printed with P. Then, two plastic films 1H and 1L are supplied from the upper side and the lower side, overlapped with each other, and sent in the length direction X thereof. The length direction X is a repeating direction of the printed pattern A.
[0014]
The pair of feed rollers 2 is used in the feed mechanism as in the publication. The films 1H and 1L pass through the heat seal bars 3 and 4 and the slitter 5 and are guided between the feed rollers 2, and the drive motor 6 drives and rotates the feed rollers 2 to rotate the films 1H and 1L. It is intermittently sent by a length corresponding to the printing pitch P. Further, when the films 1H and 1L are temporarily stopped for each intermittent feed, the films 1H and 1L are heat sealed by the heat seal bars 3 and 4, respectively. The heat seal bar includes a vertical seal bar 3 and a horizontal seal bar 4. Therefore, the films 1H and 1L are vertically sealed by the vertical seal bar 3, the vertical seal portions 7 are formed on the films 1H and 1L, the films 1H and 1L are horizontally sealed by the horizontal seal bar 4, and the films 1H and 1L are sealed. A lateral seal portion 8 is formed in 1L. The horizontal seal position is between the printing positions of the printed pattern A. Further, as the films 1H and 1L are intermittently fed, the films 1H and 1L are slit by the slitter 5, and slit lines 9 are formed in the films 1H and 1L. Thereafter, every time the films 1H and 1L are intermittently fed. When the films 1H and 1L are temporarily stopped, the films 1H and 1L are cut by the cutter 10. The cutting position is between the printing positions of the printed pattern A, and is the position of the center line of the horizontal seal portion 8. As a result, a plastic bag with the printed pattern A is manufactured.
[0015]
The downstream optical sensor 11 is provided in the feeding path of the plastic films 1H and 1L at a position downstream of the heat seal bars 3 and 4 and is disposed in the vicinity of the cutter 10 as in the same publication. . Further, the control device 12 is connected to the downstream optical sensor 11 and before each film 1H, 1L is cut by the cutter 10 every time the films 1H, 1L are intermittently fed, each film 1H, When 1 L is being sent, the optical sensor 11 detects the printing position of the plastic film. For example, the optical sensor 11 faces the upper film 1H, and the optical sensor 11 detects the printing position of the upper film 1H. The optical sensor 11 may be opposed to the lower film 1L, and the optical sensor 11 may detect the printing position of the lower film 1L. Furthermore, based on the detection signal, the drive motor 6 is controlled by the control device 12 and the feed amount of the feed roller 2 is adjusted. Thereafter, the films 1H and 1L are temporarily stopped, and the films 1H and 1L are cut by the cutter 10. As a result, the cutting positions of the plastic films 1H and 1L are adjusted, and the films 1H and 1L are accurately cut between the printing positions of the plastic films 1H and 1L.
[0016]
With respect to the printing positions of the plastic films 1H and 1L, a mark sensor is used as the downstream optical sensor 11, and a mark M is attached to the printing position of the plastic films 1H and 1L, and the mark M is detected by the mark sensor 11. As a result, the printing positions of the plastic films 1H and 1L are detected.
[0017]
This apparatus has a pair of discontinuous cut forming mechanisms 13H and 13L, and the discontinuous cut forming mechanism 13H is provided in the feed path of the upper film 1H at a position upstream of the heat seal bars 3 and 4, so that the discontinuous cuts are formed. The forming mechanism 13L is provided in the feeding path of the lower film 1L. As shown in FIG. 3, the discontinuous cut forming mechanisms 13 </ b> H and 13 </ b> L include a blade 14 and a cradle 15, and the plastic films 1 </ b> H and 1 </ b> L are guided between the blade 14 and the cradle 15. The blade 14 has discontinuous edges and extends in the width direction of the plastic films 1H and 1L. Further, the cylinder 16 is connected to the blade 14, the blade 14 is driven and moved by the cylinder 16, the plastic films 1H and 1L are sandwiched between the blade 14 and the cradle 15, and the blade 14 is the plastic films 1H and 1L. It is pressed against and bites in. Therefore, as shown in FIG. 4, discontinuous cuts 17 in the width direction are formed in the plastic films 1H and 1L.
[0018]
Furthermore, this apparatus has a pair of tension applying mechanisms 18H and 18L. At a position upstream of the heat seal bars 3 and 4, the tension applying mechanism 18H is provided in the feeding path of the upper film 1H. It is provided in the feeding path of the lower film 1L. Then, a longitudinal tension is applied to the plastic films 1H and 1L. Accordingly, the plastic films 1H and 1L are stretched by the lengthwise tension and the widthwise cut line 17, thereby correcting the printing pitch of the plastic films 1H and 1L.
[0019]
In this embodiment, a pressing roller 19 is used for the tension applying mechanisms 18 </ b> H and 18 </ b> L, and the cylinder 20 is connected to the pressing roller 19. Further, guide rollers 21 are provided on both sides thereof. The pressing roller 19 is moved by the cylinder 20, and the pressing roller 19 is pressed against the plastic films 1H and 1L between the guide rollers 21. 1H and 1L are pushed down. Further, on the downstream side of the discontinuous cut forming mechanisms 13H and 13L and the tension applying mechanisms 18H and 18L, the upper and lower films 1H and 1L are guided between the pair of grip rollers 22 and overlap each other. Thereafter, the films 1H and 1L pass through the heat seal bars 3 and 4 and the slitter 5, and are guided between the feed rollers 2. When the pressing roller 19 is pressed against the plastic films 1H and 1L, the plastic films 1H and 1L are restrained by the grip roller 22. Further, the films 1H and 1L are guided between the pair of grip rollers 23 on the upstream side of the discontinuous cut forming mechanisms 13H and 13L and the tension applying mechanisms 18H and 18L, and the pressing roller 19 is pressed against the plastic films 1H and 1L. At this time, the plastic films 1H and 1L are restrained by the grip roller 23. Simultaneously with the restraint of the plastic films 1H and 1L, or thereafter, between the guide rollers 21, the pressing roller 19 is pressed against the plastic films 1H and 1L, and the pressing films 19 press down the plastic films 1H and 1L. Accordingly, temporary tension is applied to the plastic films 1H and 1L. When a temporary tension is applied, the plastic films 1H and 1L are stretched by the discontinuous cuts 17 in the width direction, thereby correcting the printing pitch P of the plastic films 1H and 1L.
[0020]
The discontinuous cut 17 in the width direction here means a discontinuous cut extending in the width direction of the plastic films 1H and 1L, but its shape and size are not limited. As long as the plastic films 1H and 1L are stretched, it may have any shape and size, may be a single row, or may be a plurality of rows. In this embodiment, the width direction discontinuous cuts 17 are in a plurality of rows and extend in the width direction of the plastic films 1H and 1L to form a discontinuous slit shape. Therefore, when a longitudinal tension is applied, the plastic films 1H and 1L are stretched by the discontinuous cuts 17 in each row. As shown in FIG. 5, both ends of each slit-like cut 24 may be bent or curved at a certain angle. As shown in FIG. 6, the width direction discontinuous cut 25 may have a width. It is also conceivable to form circular or elliptical cuts in the width direction.
[0021]
Further, in this apparatus, it is preferable that a plurality of optical sensors 26H and 26L are provided in the feeding paths of the plastic films 1H and 1L, and the printing positions of the plastic films 1H and 1L are detected by the optical sensors 26H and 26L at different positions. . The control device 12 is connected to the optical sensors 26H and 26L, the discontinuous cut forming mechanisms 13H and 13L, and the tension applying mechanisms 18H and 18L, and the control device 12 forms discontinuous cuts based on the detection signals of the optical sensors 13H and 13L. When the mechanisms 13H and 13L and the tension applying mechanisms 18H and 18L are driven, the printing pitch P of the plastic films 1H and 1L can be accurately corrected.
[0022]
In this embodiment, a pair of optical sensors 26H and 26L are used in the printing pitch correction device, and the optical sensors 26H and 26L are provided in the supply paths for the films 1H and 1L at positions upstream of the heat seal bars 3 and 4, respectively. The discontinuous cut forming mechanisms 13H and 13L are arranged in the vicinity of each other. As in JP-A-2003-48260, the optical sensor 26H detects the printing position of the plastic film 1H in the upper film 1H supply path, and the optical sensor 26L in the lower film 1L supply path. Thus, the printing position of the plastic film 1L is detected. The optical sensors 26H and 26L are composed of mark sensors, and the printing positions are detected by the marks M on the films 1H and 1L, as in the downstream optical sensor 11. Further, the control device 12 is connected to the optical sensors 26H and 26L, the discontinuous cut forming mechanisms 13H and 13L, and the tension applying mechanisms 18H and 18L. Based on the detection signals of the optical sensors 26H and 26L, the control device 12 makes each film. When the printing positions of 1H and 1L are compared and the printing position of one of the films is downstream of the printing position of the other film, the controller 12 causes the discontinuous cut forming mechanisms 13H and 13L and the tension applying mechanism 18H, 18L is driven.
[0023]
For example, for each intermittent feed of the films 1H and 1L, when the films 1H and 1L are temporarily stopped or before being stopped, the marks M of the films 1H and 1L are detected by the optical sensors 26H and 26L. Thereby, the printing position of each film 1H and 1L is detected. Further, based on the detection signal, the control device 12 compares the marks M of the films 1H and 1L and compares the printing positions. When the mark M of the upper film 1H is downstream of the mark M of the lower film 1L, and therefore when the printing position of the upper film 1H is downstream of the printing position of the lower film 1L, In the film 1H feeding path, the control device 12 drives the discontinuous cut forming mechanism 13H to form the width direction discontinuous cuts 17, 24, 25 in the upper film 1H. At the same time or thereafter, the tension applying mechanism 18H is driven by the control device 12, and the longitudinal tension is applied to the upper film 1H. Therefore, the upper film 1H is stretched by the width direction discontinuous cuts 17, 24, 25. The stretching amount is constant and is 0.5 to 3 mm. Therefore, the printing pitch P of the film 1H is corrected and increased by the stretch amount. The stretching amount of the film 1H may be increased or decreased depending on the difference in the positions of the marks M on the films 1H and 1L.
[0024]
Further, after that, when the films 1H and 1L are sent again and temporarily stopped or before stopping, the printing positions of the films 1H and 1L are detected again and compared. When the printing position of the upper film 1H is downstream of the printing position of the lower film 1L, the discontinuous cuts 17, 24, and 25 in the width direction are formed again, and the tension in the length direction is applied again. The film 1H is stretched again. Conversely, when the mark M of the lower film 1L is downstream of the mark M of the upper film 1H, and therefore the printing position of the lower film 1L is downstream of the printing position of the upper film 1H, In the feeding path of the lower film 1L, the control device 12 drives the discontinuous cut forming mechanism 13L, and the widthwise discontinuous cuts 17, 24, and 25 are formed in the lower film 13L. At the same time or thereafter, the tension applying mechanism 18L is driven by the control device 12, and a longitudinal tension is applied to the lower film 1L. Therefore, the lower film 1L is stretched by the width direction discontinuous cuts 17, 24, 25. The stretching amount is also constant and is 0.5 to 3 mm. Therefore, the printing pitch P of the film 1L is corrected and increased by the stretch amount. The stretching amount of the film 1L may be increased or decreased depending on the difference in the positions of the marks M on the films 1H and 1L.
[0025]
In order to increase or decrease the stretching amount of the films 1H and 1L, for example, in the embodiment in which the discontinuous cut 17 of FIG. 4 is formed, when the blade 14 is pressed against the plastic films 1H and 1L and bites, the amount of biting is increased by the cylinder 16. You can adjust. Accordingly, the length of the unit cut 17 can be changed, and the stretch amount of the films 1H and 1L can be increased or decreased depending on the length of the unit cut 17. It is also possible to form a single row or a plurality of rows of discontinuous cuts 17 in the plastic films 1H and 1L, and to increase or decrease the stretch amount of the films 1H and 1L depending on the number of rows. When the pressing roller 19 is pressed against the plastic films 1H and 1L, the pressure can be changed by the cylinder 20, whereby the stretching amount of the films 1H and 1L can be increased or decreased.
[0026]
Thereafter, for each intermittent feed of the films 1H and 1L, the printing position of each film 1H and 1L is detected and compared each time, and the printing position of one of the films is downstream of the printing position of the other film. In each case, the discontinuous cuts 17, 24, 25 in the width direction are formed and the tension in the length direction is applied, and the printing pitch P of one of the films is corrected and increased. As a result, the printing pitch P of each film 1H, 1L is accurately corrected, and minute errors in the printing pitch P do not accumulate gradually. Therefore, the print patterns A of the films 1H and 1L do not shift due to the accumulated error, and the print patterns A of the films 1H and 1L are aligned with each other.
[0027]
Further, with respect to the discontinuous cut forming mechanisms 13H and 13L of this apparatus, the installation positions are selected by the printing pitch P of the plastic films 1H and 1L, and the plastic films 1H and 1L are formed by the discontinuous cuts 17, 24 and 25 in the width direction. Then, the portion reaches the position of the lateral seal bar 4, and the plastic films 1H and 1L are laterally sealed by the lateral seal bar 4 at the portions of the width direction discontinuous cuts 17, 24 and 25. Therefore, the width direction discontinuous cuts 17, 24, 25 are located in the lateral seal portion 8, and the width direction discontinuous cuts 17, 24, 25 are not left in the main body after the plastic bag is manufactured. When the respective films 1H and 1L are cut by the cutter 10, they are cut on both sides of the width direction discontinuous cuts 17, 24 and 25 so that the width direction discontinuous cuts 17, 24 and 25 are removed. Good.
[0028]
As described in Japanese Patent Application Laid-Open No. 2003-48260, a gusset tape film is inserted between the upper and lower films 1H and 1L, and a side gusset or a bottom gusset of a plastic bag is formed by the gusset tape film. And you may make it correct the printing pitch of the film of a gusset tape with this apparatus.
[0029]
As described in the publication, the printing pitch of a specific film is selected to be slightly smaller than the printing pitch of other films. Then, the printing position of each film is detected by the optical sensor, and when the printing position of the specific film is downstream of the printing position of the other film, the discontinuous cut forming mechanism is controlled by the control device based on the detection signal of the optical sensor. Then, the tension applying mechanism is driven to form a discontinuous cut in the width direction on the specific film, a tension in the length direction is applied, and the specific film is stretched by the discontinuous cut in the width direction. Further, the stretch amount may be selected to be slightly larger than the difference in printing pitch, thereby correcting the printing pitch of a specific film so that the print patterns of each film are aligned with each other.
[0030]
As described in the publication, the upstream sensor is disposed at a predetermined distance from the downstream sensor in the plastic film feeding path, and the distance corresponds to an integral multiple of the printing pitch of the plastic film. Then, the printing position of the plastic film is detected by the upstream and downstream sensors, and the total value of the printing pitch between the upstream and downstream sensors is monitored by the control device based on the detection signal. Further, when the total value of the printing pitch does not reach the predetermined value, the control device drives the discontinuous cut forming mechanism and the tension applying mechanism to form the discontinuous cut in the width direction on the plastic film and gives the tension in the length direction. The plastic film is stretched by the width direction cut. Thereby, the printing pitch of the plastic film may be corrected and the average pitch may be made constant.
[0031]
In short, a plurality of optical sensors can be arranged in the same manner as that of Japanese Patent Application Laid-Open No. 2003-48260, and thereby the same function and effect as that of the same publication can be obtained. In addition, in the case of this apparatus, it is not necessary to provide a special heater as in the publication. The blades 14 and the cradle 15 are used for the discontinuous cut forming mechanisms 13H and 13L, and these need only be provided in the plastic film feed path, and the cost is low. As in the publication, there is no need to pressurize and heat the plastic film with a heater to soften it, and it is not necessary to select the pressure, temperature and time accurately. There is no need to change and adjust the pressure, temperature and time with the plastic film. It is only necessary to press the blade 14 against the plastic film to form the widthwise discontinuous cuts 17, 24, 25 in the plastic film, and selection and adjustment are not required.
[0032]
FIG. 7 shows another embodiment. Also in this embodiment, discontinuous cut forming mechanisms 13H and 13L are provided in the feeding paths of the films 1H and 1L at positions upstream of the heat seal bars 3 and 4, respectively. The discontinuous cut forming mechanisms 13H and 13L have the same configuration as that of FIG. Accordingly, discontinuous cuts 17, 24, 25 in the width direction are formed in the plastic films 1H, 1L.
[0033]
Further, also in the embodiment of FIG. 7, tension applying mechanisms 18H and 18L are provided in the feeding paths of the respective films 1H and 1L at positions upstream of the heat seal bars 3 and 4. Then, a longitudinal tension is applied to the plastic films 1H and 1L. However, in the embodiment shown in FIG. 7, unlike the one shown in FIG. 1, a tension roller 18H, 18L uses a dancer roller 27 instead of the pressing roller 19, and this is supported by an arm 28. Acts on the dancer roller 27, and the dancer roller 27 is pressed against the plastic films 1H and 1L. Therefore, continuous tension is applied to the plastic films 1H and 1L. When the width direction discontinuous cuts 17, 24, 25 are formed, the plastic films 1H, 1L are stretched by continuous tension, and thereby the printing pitch P of the plastic films 1H, 1L is corrected. The dancer roller 27 is for applying continuous tension to tension the plastic films 1H and 1L, and as such is generally used.
[0034]
Further, also in the embodiment of FIG. 7, a plurality of optical sensors 26H and 26L are provided in the feeding paths of the plastic films 1H and 1L, and the printing positions of the plastic films 1H and 1L are detected by the optical sensors 26H and 26L at different positions. Is done. For example, as in the embodiment of FIG. 1, a pair of optical sensors 26H and 26L are used in the printing pitch correction device, and the optical sensors 26H and 26L are positioned upstream of the heat seal bars 3 and 4, respectively. Is provided at a position near the discontinuous cut forming mechanisms 13H and 13L. In the supply path of the upper film 1H, the optical sensor 26H detects the printing position of the upper film 1H, and the optical sensor 26L detects the printing position of the lower film 1L. Further, the control device 12 is connected to the optical sensors 26H and 26L and the discontinuous cut forming mechanisms 13H and 13L, and the discontinuous cut forming mechanisms 13H and 13L are driven by the control device 12 based on the detection signals of the optical sensors 26H and 26L. The Therefore, the printing pitch P of the plastic films 1H and 1L can be accurately corrected.
[0035]
A gusset tape film may be inserted between the upper and lower films 1H and 1L, a continuous tension is applied to the gusset tape film, and the print pitch of the gusset tape film may be corrected by a widthwise cut. When the print pitch of a specific film is selected to be slightly smaller than the print pitch of another film and the print position of the specific film is downstream of the print position of the other film, And a specific film may be stretched by discontinuous cuts in the width direction, thereby forcing a specific film printing pitch so that the print patterns of each film are aligned with each other. Continuous tension is applied to the plastic film, the printing position of the plastic film is detected by the upstream and downstream sensors, the total print pitch value between the upstream and downstream sensors is monitored by the control device, and the total print pitch is measured. When the value does not reach the predetermined value, the plastic film may be stretched by the cut in the width direction, thereby correcting the printing pitch of the plastic film and making the average pitch constant.
[0036]
In the embodiment of FIG. 7 as well, the discontinuous cut forming mechanisms 13H and 13L are provided in the feeding path of the plastic films 1H and 1L, and the width direction cuts 17, 24 and 25 are formed in the plastic films 1H and 1L. Low, no selection and adjustment required.
[0037]
In the embodiment of FIG. 1 or FIG. 7, the optical sensors 26H and 26L may be moved along the feeding path of the plastic films 1H and 1L so that the positions thereof can be adjusted as appropriate. When the optical sensors 26H and 26L are connected by a link mechanism and moved along the feeding path of the plastic films 1H and 1L, the optical sensors 26H and 26L may be synchronized by the link mechanism.
[0038]
【The invention's effect】
As described above, according to the present invention, it is only necessary to provide a discontinuous cut forming mechanism in the plastic film feed path and form a discontinuous cut in the width direction in the plastic film, the cost is low, and selection and adjustment are required. It is not possible to achieve the intended purpose.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of the present invention.
FIG. 2 is a plan view showing a printed pattern of the plastic film of FIG.
FIG. 3 is an explanatory view of a discontinuous cut forming mechanism of the apparatus of FIG. 1;
4 is an explanatory view showing discontinuous cuts in the width direction of the plastic film of FIG. 1. FIG.
FIG. 5 is an explanatory diagram showing another embodiment.
FIG. 6 is an explanatory diagram showing another embodiment.
FIG. 7 is a side view showing another embodiment.
[Explanation of symbols]
1H, 1L plastic film
2 Feed roller
12 Control device
13H, 13L Discontinuous cut formation mechanism
17, 24, 25 Discontinuous cuts in the width direction
18H, 18L tensioning mechanism
26H, 26L optical sensor

Claims (5)

A feed mechanism for feeding a plastic film having a printed pattern repeatedly printed with a substantially constant printing pitch in the length direction;
A discontinuous cut forming mechanism for forming a discontinuous cut in the width direction in the plastic film;
It is provided in a feeding path of the plastic film, and includes a tension applying mechanism that applies a longitudinal tension to the plastic film,
The plastic film printing pitch correcting apparatus, wherein the plastic film is stretched by the longitudinal tension and the discontinuous cut in the width direction, thereby correcting a printing pitch of the plastic film. A pressing roller is used for the tension applying mechanism, the pressing roller is pressed against the plastic film, a temporary tension is applied to the plastic film, and when the temporary tension is applied, The printing pitch correction device according to claim 1, wherein the plastic film is stretched. Further, a plurality of optical sensors that are provided in the plastic film feed path and detect the printing position of the plastic film at different positions from each other;
And a control device that is connected to the optical sensor, the discontinuous cut forming mechanism, and the tension applying mechanism, and that drives the discontinuous cut forming mechanism and the tension applying mechanism based on a detection signal of the optical sensor. The printing pitch correction apparatus according to claim 2. A dancer roller is used for the tension applying mechanism, and when the dancer roller is pressed against the plastic film, a continuous tension is applied to the plastic film, and the width direction cut is formed, the continuous tension causes the plastic film to The printing pitch correction device according to claim 1, wherein the printing pitch correction device is stretched. Further, a plurality of optical sensors that are provided in the plastic film feed path and detect the printing position of the plastic film at different positions from each other;
The printing pitch according to claim 4, further comprising: a control device that is connected to the optical sensor and the discontinuous cut forming mechanism and drives the discontinuous cut forming mechanism based on a detection signal of the optical sensor. Straightening device.

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