Patent Description:
Bag making apparatuses for successively making bags from a continuous sheet panel and a continuous zipper are well known as disclosed in Patent documents <NUM> and <NUM>. The bag making apparatus includes a welding device configured to weld the sheet panel and the zipper to each other, and a cross cut device configured to cross-cut the sheet panel and the zipper in their width direction after welding so as to shape a bag.

The welding device in each of Patent documents <NUM> and <NUM> includes a pair of pressure rollers opposing each other for pressurizing the sheet panel and the zipper, a feed device configured to intermittently feed the sheet panel and the zipper in their longitudinal direction through the pair of pressure rollers in a state in which they are superposed on each other, and a laser device configured to irradiate the zipper with a laser beam at a position upstream of the pair of pressure rollers.

Irradiating the zipper with a laser beam causes its irradiated part to be heat-melted by the laser beam. The sheet panel and the zipper are then guided to the pair of pressure rollers to be superposed on each other. When the sheet panel and the zipper are fed through the pair of pressure rollers, they are pressurized by the pair of pressure rollers and thus welded to each other.

The temperature at the irradiated part is decreasing while this part is being fed from the irradiation position of the laser beam to the pair of pressure rollers. For proper welding, the molten state of the irradiated part should be maintained until the irradiated part reaches the pair of pressure rollers.

The sheet panel and the zipper are intermittently fed. This means that the sheet panel and the zipper are repeatedly fed and paused. During the pause phase of the intermittent feed cycle, the irradiated part which is located in the section from the irradiation position to the pair of pressure rollers cools down to return from the molten state to the non-molten state. When the sheet panel and the zipper are then fed again, the irradiated part is pressed in the non-molten state against the sheet panel by the pair of pressure rollers, and consequently fails to be welded to the sheet panel. In this way, the unwelded part, which was subject to the laser irradiation and the pressurization but failed to be welded, is generated every intermittent feed cycle. The unwelded part can be a cause of leakage in making bags, have an influence on the quality of the bags, and in addition, cause the loss of material.

The present disclosure provides a bag making apparatus comprising the features of independent claim <NUM> capable of reducing problems that can be caused by such an unwelded part.

Patent document <NUM>: <CIT> Patent document <NUM>: <CIT> Patent document <NUM>: <CIT> Patent document <NUM>: <CIT> Patent document <NUM>: <CIT><CIT> Patent document <NUM>:<CIT>.

According to the invention, there is provided a bag making apparatus for successively making bags from a continuous sheet panel and a continuous strip member. The bag making apparatus includes: a feed device configured to intermittently feed the sheet panel and the strip member in a longitudinal direction of the sheet panel and the strip member; a welding device configured to weld the sheet panel and the strip member to each other in a zone where the sheet panel is intermittently fed by the feed device; and a cut device disposed downstream of the welding device and configured to cross-cut the sheet panel and the strip member in a width direction of the sheet panel during every intermittent feed cycle. The welding device includes: a pressure unit comprising a pair of pressure rollers for pressurizing the sheet panel and the strip member superposed on each other during a feed phase of an intermittent feed cycle; and a laser unit configured to irradiate the sheet panel or the strip member with a laser beam at an irradiation position upstream away of a pressure position of the pressure unit to melt the sheet panel or the strip member using the laser beam, wherein a part of the sheet panel or the strip member irradiated with the laser beam returns to a non-molten state due to decrease in temperature in a section from the irradiation position to the pressure position during a pause phase of an intermittent feed cycle, so that an unwelded part is generated every intermittent feed cycle, The bag making apparatus further comprising a movement device for moving the pressure unit and the laser unit together upstream and downstream while maintaining a relative positional relationship between the pressure position and the irradiation position; and a control device configured to control the movement device to move the pressure unit and the laser unit together upstream and downstream during a pause phase of an intermittent feed cycle, thereby adjusting a position on the sheet panel where the unwelded part is generated, in the longitudinal direction of the sheet panel.

For example, the bag making apparatus may further include: a sensor for detecting a position of the welding device; an indicator; and a control device configured to determine, based on detection by the sensor, a relative positional relationship between the position of the welding device and a separation position which is spaced upstream away from a cross cut position of the cut device by an integer multiple of a pitch of intermittent feed along a feed path, wherein the control device is further configured to indicate information regarding said relative positional relationship on the indicator.

The information may include an offset distance of a midpoint between the pressure position and a downstream end of the irradiation position relative to the separation position.

For example, the bag making apparatus may further include: a sensor for detecting a position of the welding device, wherein the control device is configured to control the movement device based on detection by the sensor to position the pressure unit and the laser unit.

The control device may be configured to control the movement device based on detection by the sensor to make a midpoint between the pressure position and a downstream end of the irradiation position spaced away from the cross cut position by an integer multiple of a pitch of intermittent feed along a feed path.

For example, the bag making apparatus may further include: a sensor for detecting positions of print patterns repeatedly printed on the sheet panel; a movement device configured to move the pressure unit, the laser unit and the sensor together whiling maintaining a positional relationship between the pressure position and the irradiation position; and a control device configured to control the movement device based on detection by the sensor to position the pressure unit and the laser unit.

For example, the bag making apparatus may further include: at least one sensor for detecting positions of print patterns repeatedly printed on the sheet panel and detecting positions of unwelded parts generated due to failure by the welding device to weld the sheet panel and the strip member; an indicator; and a control device configured to determine a relative positional relationship between a print pattern and an unwelded part and to indicate information regarding said relative positional relationship on the indicator.

For example, the bag making apparatus may further include: at least one sensor for detecting positions of print patterns repeatedly printed on the sheet panel and detecting positions of unwelded parts generated due to failure by the welding device to weld the sheet panel and the strip member; a movement device for moving the pressure unit and the laser unit together upstream and downstream while maintaining a relative positional relationship between the pressure position and the irradiation position; and a control device configured to control the movement device based on detection by the at least one sensor to position the pressure unit and the laser unit.

For example, the bag making apparatus may further include a movement device including a handle. The movement device may be configured to move, in response to operation of the handle, move the pressure unit and the laser unit together upstream and downstream while maintaining a relative positional relationship between the pressure position and the irradiation position.

The pressure position may be a nip position of the pair of pressure members.

The laser unit may be configured to interlink irradiation intensity of the laser beam with feed speed of intermittent feed.

The bag making apparatus may further include a seal device disposed downstream of the welding device and upstream of the cut device and configured to seal the sheet panel in the width direction of the sheet panel during every intermittent feed cycle. A distance along a feed path between a cross cut position of the cut device and a seal width center of a seal position of the seal device may be an integer multiple of a pitch of intermittent feed.

The bag making apparatus is configured to make bags from the sheet panel and a continuous zipper as the strip member.

Bag making apparatuses according to the implementations will be described below with reference to the drawings. Same or similar components in the respective implementations are indicated by the same numerals.

An example bag making apparatus is illustrated in <FIG>. The bag making apparatus successively makes bags <NUM> from a continuous sheet panel <NUM> and a continuous strip member <NUM>. The strip member <NUM> has a narrower width than that of the sheet panel <NUM>.

The bag making apparatus includes a feed device <NUM> that intermittently feeds the sheet panel <NUM> and the strip member <NUM> welded to the sheet panel <NUM> as described below, in their longitudinal (continuous) direction. The direction Y<NUM> designates the feed direction. The feed device <NUM> in the implementation includes ono or more pairs of drive rollers <NUM>. <FIG> illustrates two pairs of drive rollers <NUM> spaced from each other. The pairs of drive rollers <NUM> intermittently feed the sheet panel <NUM> and the strip member <NUM> by intermittently rotating in synchronization with each other while sandwiching these. The feed device <NUM> intermittently feeds the sheet panel <NUM> and the strip member <NUM> at the feed pitch determined depending on the dimensions of the bags <NUM>.

The bag making apparatus supports a roll <NUM>' at the most upstream end thereof. The sheet panel <NUM> is unrolled from the roll <NUM>' in the longitudinal direction thereof at a constant speed. The bag making apparatus includes a folding device <NUM> that folds the sheet panel <NUM> in half. The folding device <NUM> includes a triangular plate <NUM>, a pair of suction rollers <NUM> and guide rollers <NUM>. The sheet panel <NUM> is guided to the triangular plate <NUM> via the guide rollers <NUM> to be folded in half by the triangle plate <NUM> and the pair of suction rollers <NUM>.

As a result of folding the sheet panel <NUM> in half, the sheet panel <NUM> has two panel parts <NUM> as its two layers. The reference sign <NUM> in <FIG> designates the folded edge resulting from folding the sheet panel <NUM> in half. The reference sign <NUM> in <FIG> designates the opposite side edges aligned with each other due to folding the sheet panel <NUM> in half.

The bag making apparatus includes a dancer device <NUM> disposed downstream of the folding device <NUM>. The dancer device <NUM> includes a dancer roller. The dancer device <NUM> appropriately switches the feed of the sheet panel <NUM> from continuous feed to intermittent feed. Thus, the zone <NUM> upstream of the dancer device <NUM> is a zone where the sheet panel <NUM> is continuously fed, whereas the zone <NUM> downstream of the dancer device <NUM> is a zone where the sheet panel <NUM> is intermittently fed by the feed device <NUM>.

The bag making apparatus includes a welding device <NUM> disposed downstream of the dancer device <NUM>. The welding device <NUM> welds the sheet panel <NUM> and the strip member <NUM> to each other in the zone <NUM> where the sheet panel <NUM> is intermittently fed by the feed device <NUM>.

The welding device <NUM> in the implementation includes a pair of expansion rollers <NUM> arranged downstream of the pair of guide rollers <NUM> and upstream of the pair of pressure rollers <NUM>. The sheet panel <NUM> is expanded by the pair of expansion rollers <NUM> on the side of the side edge <NUM> in the zone from the pair of guide rollers <NUM> to the pair of pressure rollers <NUM>, so that a space is created between the two panel parts <NUM>.

As illustrated in <FIG>, the continuous strip member <NUM> is guided, diverted and inserted between the two panel parts <NUM> by a guide roller <NUM> through the space obtained by the pair of expansion rollers <NUM>. The welding device <NUM> welds the sheet panel <NUM> and the strip member <NUM> to each other using laser radiation and pressurizing. Specifically, the welding device <NUM> welds the strip member <NUM> to the two panel parts <NUM>.

The bag making apparatus further includes a seal device <NUM> arranged downstream of the welding device <NUM>. The seal device <NUM> heat-seals the sheet panel <NUM> in the width direction of the sheet panel <NUM> over the entire width of the sheet panel <NUM> to form a cross sealed section <NUM> (<FIG>) during every intermittent feed cycle, specifically during every pause phase of the intermittent feed cycle. The seal device <NUM> in the implementation includes one or more pairs of heat seal members <NUM> (for example, heat seal bars). <FIG> illustrates two pairs of heat seal members <NUM>. It sandwiches the two panel parts <NUM> using the pairs of seal members <NUM> to heat-seal them to each other, thereby forming the cross sealed section <NUM>. Alternatively, the seal device <NUM> may ultrasonic-seal the sheet panel <NUM> using ultrasonic-sealing means, thereby forming the cross sealed section <NUM>.

The bag making apparatus further includes a cut device <NUM> disposed downstream of the seal device <NUM>, specifically at the most downstream end of the bag making apparatus. The cut device <NUM> cross-cuts the sheet panel <NUM> and the strip member <NUM> in the width direction of the sheet panel <NUM> during every intermittent feed cycle of the sheet panel <NUM>, specifically during every pause phase of the intermittent feed cycle. Every cross-cutting, the bag <NUM> illustrated in <FIG> is made from the sheet panel <NUM> and the strip member <NUM> cut off by the cross-cutting. The cut device <NUM> cross-cuts the sheet panel <NUM> and the strip member <NUM> at the width center of the cross sealed section <NUM>. Therefore, the distance between the cut device <NUM> and the seal device <NUM> along the feed path for the sheet panel <NUM>/strip member <NUM> is adjusted during every pause phase of the intermittent feed cycle such that the width center of a cross sealed section <NUM> is aligned with the cross cut position Pr at which the cut device <NUM> cross-cuts the sheet panel <NUM> and the strip member <NUM>.

The bag making apparatus further includes an indicator <NUM> for indicating bag making condition and information about a position of each device of the bag making apparatus. The bag making condition includes, for example, information related to the dimensions of the bags to be made, the bag making speed, and the temperature of the seal members <NUM>. The indicator <NUM> may be a display. The indicator <NUM> may include a touch screen, buttons, etc., and may be configured as operating means to be operated by an operator.

The bag making apparatus further includes a control device <NUM> electrically connected to at least above devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> to control these devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. The control device <NUM> includes a controller.

Welding using the welding device <NUM> will be described below.

The sheet panel <NUM> in the implementation is a plastic film. The bag <NUM> in the implementation is, therefore, a plastic bag. The sheet panel <NUM> is a laminated film having one surface composed of a base layer such as PET and the other surface composed of a sealant layer such as polyethylene, which has a lower melting point than the base layer. The sheet panel <NUM> is folded in half by the folding device <NUM> such that the sealant layers face each other. When the sheet panel <NUM> is heat-sealed by the seal device <NUM>, this causes the two panel parts <NUM> to be heat-sealed to each other due to the melting of the sealant layer, so that a cross sealed section <NUM> is formed.

The sheet panel <NUM> is not limited to the above configurations. The sheet panel <NUM> may consists of mono-material such as polyethylene, polypropylene, etc. Also, the sheet panel <NUM> may be composed of paper as a base and a resin coating the paper. In other words, the sheet panel <NUM> may consist of a mono-material or multiple materials, as long as it is possible to implement the bag making.

As illustrated in <FIG>, the strip member <NUM> in the implementation is a zipper which allows the bag <NUM> to be freely opened and closed. As in Patent documents <NUM> and <NUM>, a zipper as the continuous strip member <NUM> includes a male member <NUM> and a female member <NUM> which are detachably fitted to each other. The male member <NUM> has a surface <NUM> to be welded to one panel part <NUM>, and the female member <NUM> has a surface <NUM> to be welded to the other panel part <NUM>. The strip member <NUM> is supplied and then welded to the sheet panel <NUM> with the male member <NUM> and the female member <NUM> fitted to each other.

The strip member <NUM> in the implementation is made of resin. Alternatively, as long as at least surface <NUM> to be welded of the strip member <NUM> is made of a material such as resin that allows for welding, the other parts of the strip member <NUM> may be made of other materials. That is, the strip member <NUM> may consist of a mono-material or multiple materials as long as it is possible to implement the bag making.

<FIG> schematically illustrates the positional relationship among main components of an example welding device <NUM>. The welding device <NUM> includes a pressure unit <NUM> for pressurizing the sheet panel <NUM> and the strip member <NUM> superposed on each other. The pressure unit <NUM> in the implementation includes the aforementioned pair of pressure rollers <NUM> as a pair of pressure members opposing each other for pressurizing the sheet panel <NUM> and the strip member <NUM>. The sheet panel <NUM> and the strip member <NUM> are fed in a superposed state by the feed device <NUM> though the pair of pressure rollers <NUM>. The sheet panel <NUM> and the strip member <NUM> are pressurized by the pair of pressure rollers <NUM> while passing through the pair of pressure rollers <NUM>. Thus, the pressure position P<NUM> of the pressure unit <NUM> in the implementation is a nip position of the pair of pressure rollers <NUM>.

The welding device <NUM> includes at least one laser unit <NUM> that irradiates the sheet panel <NUM> or the strip member <NUM> with a laser beam <NUM> at a position upstream of the pressure position P<NUM> to melt the sheet panel <NUM> or the strip member <NUM> using the laser beam <NUM>.

Two laser units <NUM> are provided in the implementation, each of which includes a laser light source, an optical system and so on. One laser unit <NUM> is arranged to irradiate one surface <NUM> of the strip member <NUM> with the laser beam <NUM> in a spot manner, the other laser unit <NUM> is arranged to irradiate the other surface <NUM> of the strip member <NUM> with the laser beam <NUM> in a spot manner.

As in Patent documents <NUM> and <NUM>, each laser unit <NUM> is arranged to irradiate the strip member <NUM> with the laser beam <NUM> at the irradiation angle θ (<NUM>< θ =< <NUM>). As illustrated in <FIG>, each surface <NUM> is made of a light absorption layer <NUM> which absorbs the laser beam <NUM>.

As in Patent documents <NUM> and <NUM>, the laser unit <NUM> interlinks the irradiation intensity of the laser beam <NUM> with the speed of the intermittent feed to maintain uniformity of the strength of the welding when welding with the laser beam <NUM> during the intermittent feed. It increases the irradiation intensity when the sheet panel <NUM> is fed at a higher speed, correspondingly it decreases the irradiation intensity when the sheet panel <NUM> is fed at a lower speed. In other words, the laser unit <NUM> is configured to radiate the laser beam <NUM> while controlling the irradiation intensity of the laser beam <NUM> in accordance with the feed speed.

The example of this is illustrated in <FIG>. In the pattern <NUM>, the irradiation intensity is in complete proportion to the feed speed, which means that the irradiation intensity is zero (i.e., the laser beam <NUM> is not radiated) when the feed speed is zero. In contrast, in the pattern <NUM>, the irradiation intensity is in proportion to the feed speed but is controlled such that it is not less than the minimum predetermined value W<NUM> (<NUM> < W<NUM><W<NUM>; W<NUM> is the irradiation intensity value when the feed speed is maximum). This means that the laser beam <NUM> is radiated continuously while the web <NUM> is not only being fed but also being paused. The laser unit <NUM> sets the output to zero for the pattern <NUM>, whereas it does not set the output to zero for the pattern <NUM>. Since the laser unit <NUM> is generally subjected to the highest load when outputting from the zero-output state, the pattern <NUM>, which has lesser burden on the laser unit <NUM> than the pattern <NUM>, is preferable.

As illustrated in <FIG>, the welding device <NUM> includes a guide body <NUM> for guiding the strip member <NUM> through the pair of pressure rollers <NUM> without meandering of the strip member <NUM>. <FIG> is a D-D line cross section of <FIG>, illustrating a cross-section of the guide body <NUM>. The guide body <NUM> has a hole <NUM> through which the strip member <NUM> passes. As is clear from <FIG>, the guide hole <NUM> has a vertical dimension slightly larger than the vertical dimension of the strip member <NUM> and a horizontal dimension slightly larger than the horizontal dimension of the strip member <NUM>.

As illustrated in <FIG>, when the sheet panel <NUM> and the strip member <NUM> are fed (<FIG>: <NUM> < t < t<NUM>), the sheet panel <NUM> (panel parts <NUM>) is guided through a pair of pressure rollers <NUM> via the pair of expansion rollers <NUM>. The sheet panel <NUM> and the strip member <NUM> are caused to be superposed on each other at a position right before the pressure position P<NUM>. In the implementation, the strip member <NUM> is sandwiched between the two panel parts <NUM>. At this time, one surface <NUM> of the strip member <NUM> comes into contact with one of the panel parts <NUM>, and the other surface <NUM> of the strip member <NUM> comes into contact with the other panel part <NUM>. The sheet panel <NUM> and the strip member <NUM> are then fed through the pair of pressure rollers <NUM> in a superposed state.

When the strip member <NUM> is fed through the radiation position R (<FIG>) spaced upstream away from the pressure position P<NUM>, the surface <NUM> (light absorption layer <NUM>) is irradiated with the laser beam <NUM> to be melted by the laser beam <NUM>. The molten surface <NUM> then comes into contact with the sheet panel <NUM> (the panel part <NUM>) and passes through the pair of pressure rollers <NUM> in this state. When the sheet panel <NUM> and the strip member <NUM> are fed through the pair of pressure rollers <NUM>, they are pressurized at the pressure position P<NUM> by the pair of pressure rollers <NUM>. As a result, the sheet panel <NUM> and the strip member <NUM> are welded to each other.

<FIG> illustrates the situation when the time is t, (see <FIG>), i.e., the moment the sheet panel <NUM> and the strip member <NUM> have just started to be paused. The hatched part in line L<NUM> indicates the welded part. The surface <NUM> in the section P<NUM>-P<NUM> is melted as it has been irradiated with the laser beam <NUM>, but is not welded to the web <NUM>. <FIG> illustrates only one of the panel parts <NUM> and one of the pressure rollers <NUM>. <FIG> separately illustrates the end part of the line L<NUM> irradiated with the laser beam <NUM> and the start part of line L<NUM> to be irradiated with the laser beam <NUM> for the purpose of convenience.

Since, the part of the strip member <NUM> located in the section P<NUM>-P<NUM> during a pause phase of the intermittent feed cycle has been irradiated with the laser beam <NUM> during the previous feed of the sheet panel <NUM>, the surface <NUM> thereof is in the molten state when t = t<NUM>. However, it returns to the non-molten state (solid state) during the pause phase of the intermittent feed cycle due to decrease in temperature. Consequently, when the sheet panel <NUM> and the strip member <NUM> are pressurized by the pair of pressure rollers <NUM> during the next feed phase of the intermittent feed cycle (t > t<NUM>), they fail to be welded to each other in the area where they have returned to the non-molten state. The laser beam <NUM> starts to radiate at the position P<NUM>. Thus, the part of the strip member <NUM> located in the section P<NUM>-P<NUM> during a pause phase of the intermittent feed cycle will be welded to the sheet panel <NUM> during the next feed phase of the intermittent feed cycle.

In other words, the unwelded area q (<FIG>), which is an area in the feed direction Y<NUM> where the sheet panel <NUM> and the strip member <NUM> are completely not welded to each other and has a length corresponding to the distance of the section P<NUM>-P<NUM>, is generated every intermittent feed cycle. Specifically, the distance of the section P<NUM>-P<NUM> is a distance between the pressure position P<NUM> and the downstream end of the irradiation position R.

The part of the surface <NUM> in the section P<NUM>-P<NUM> is partially welded and not partially welded due to the spot shape of the cross section <NUM> of the laser beam <NUM>. Therefore, the unwelded part Q (<FIG>), which is not welded although was subject to the laser radiation and the pressurization and has a length corresponding to the distance of the section P<NUM>-P<NUM>, is generated every intermittent feed cycle. The downstream part with the length corresponding to the distance of the section P<NUM>-P<NUM> in the unwelded part Q is the unwelded area q defined as described above.

The pressure unit <NUM> and the laser units <NUM> are configured to be movable upstream (i.e., in the direction Y<NUM>) and downstream (i.e., in the direction Y<NUM>) together with respect to the sheet panel <NUM>, the strip member <NUM>, the seal device <NUM>, the cut device <NUM>, and so on, while maintaining the relative positional relationship between the pressure position P<NUM> and the irradiation position R.

For this, the bag making apparatus further includes a movement device <NUM> (<FIG>) that moves the pressure unit <NUM> and the laser units <NUM> together upstream and downstream with respect to the sheet panel <NUM>, the strip member <NUM>, the seal device <NUM>, the cut device <NUM>, and so on. In the implementation, the pressure unit <NUM>, the laser units <NUM>, the pair of guide rollers <NUM>, the pair of expansion rollers <NUM>, and the guide body <NUM>, i.e., the whole of the welding device <NUM>, are moved in unison by the movement device <NUM>.

<FIG> schematically illustrates an example movement device <NUM> of <FIG>. In <FIG>, the presser unit <NUM>, the laser units <NUM>, the pair of guide rollers <NUM>, the pair of expansion rollers <NUM>, and the guide body <NUM> are illustrated in solid lines, and the components located in front of them on the paper are illustrated in single-dotted lines.

The movement device <NUM> includes a support arrangement <NUM> that supports the pressure unit <NUM>, the laser units <NUM>, the pair of guide rollers <NUM>, the pair of expansion rollers <NUM>, and the guide body <NUM> with the positional relationships illustrated in <FIG> and <FIG>.

In the implementation, the support arrangement <NUM> has two side frames <NUM> facing each other in the width direction of the sheet panel <NUM> with a space larger than the width of the sheet panel <NUM> (which has been folded in half) and interposing the sheet panel <NUM> which is on the feed path. Of the two side frames, the side frame closer to the side edge <NUM> (<FIG>) is indicated by the reference sign <NUM>, whereas the side frame closer to the folded edge <NUM> (<FIG>) is not illustrated.

The pair of pressure rollers <NUM> and the pair of guide rollers <NUM> are rotatably supported by both side frames <NUM>. The pair of expansion rollers <NUM> is rotatably supported by one side frame <NUM> only.

The support arrangement <NUM> further includes base shafts <NUM> rotatably supported by the side frame <NUM> and extending by the predetermined distance in the direction towards the side frame that is not illustrated. Each of the laser units <NUM> is supported by the base shaft <NUM>. The base shaft <NUM> has been rotated with respect to the side frame <NUM>, so that the irradiation angle θ has been adjusted in advance, and it is fixed to the side frame <NUM> in the adjusted state. The support arrangement <NUM> include a guide bracket (not illustrated) via which the guide body <NUM> is supported by the side frame <NUM>.

Thus, in the implementation, when the sheet panel <NUM> is set in the bag making apparatus, the laser units <NUM> and the guide body <NUM> are arranged between the panel parts <NUM> which are expanded by the pair of expansion rollers <NUM>.

<FIG> is an E-line arrow view of <FIG>. As illustrated in <FIG>, the movement device <NUM> includes at least one rack <NUM> and at least one pinion <NUM> as a mechanism for moving the support arrangement <NUM> in the directions Y<NUM> and Y<NUM>. The rack <NUM> is fixed to the main frame <NUM> of the bag making apparatus to extend in the direction Y<NUM>. The pinion <NUM> is engaged with the rack <NUM> and its pinion shaft <NUM> is rotatably received by the support arrangement <NUM>.

Specifically, the racks <NUM> are provided for each of the side frames <NUM> of the support arrangement <NUM>, and the pinions <NUM> are located in the upstream and downstream portions of the side frames <NUM>, and their pinion shafts <NUM> are inserted into the side frames <NUM>.

As illustrated in <FIG>, the movement device <NUM> further includes a handle <NUM> to be operated by an operator for movement of the support arrangement <NUM>, and a clamp <NUM> for fixing the support arrangement <NUM>. The handle <NUM> is operably connected to the pinion shaft <NUM> of any one of the pinions <NUM>. The clamp <NUM> is arranged to be able to releasably fix the pinion shat <NUM>.

With the above configuration, the movement device <NUM> moves the support structure <NUM> (i.e., the pressure unit <NUM>, the laser units <NUM>, the pair of guide rollers <NUM>, the pair of expansion rollers <NUM>, and the guide body <NUM>) upstream and downstream with respect to the sheet panel <NUM>, the strip member <NUM>, the seal device <NUM>, and the cut device <NUM>, in response to the operation of the handle <NUM> by an operator. At this time, the relative positional relationship between the pressure position P<NUM> and the irradiation position R (see <FIG>) is being maintained. After the movement, it is possible to secure the positions of the units <NUM> and <NUM> by fixing the pinion shaft <NUM> using the clamp <NUM>.

Alternative to the manual operation using the handle <NUM>, the movement device <NUM> may include a drive source <NUM> for automatically moving the support arrangement <NUM>, as illustrated in <FIG>. The drive source <NUM> is operably connected to the pinion shaft <NUM>. The drive source <NUM> is, for example, a servo motor. The drive source <NUM> may be connected to and controlled by the control device <NUM>. This allows the control device <NUM> to control the movement device <NUM> to automatically move the units <NUM> and <NUM> upstream and downstream together. The units <NUM> and <NUM> may be moved based on detection by the various sensors described below, or in response to the above operation means receiving the operator's input operation.

This allows the position of the unwelded part Q on the sheet panel <NUM>, which is generated as described above, to be adjusted in its longitudinal direction. In other words, it is possible to adjust the unwelded part(s) Q with respect to the devices located downstream of the welding device <NUM> (e.g., the seal device <NUM>, the cut device <NUM>, etc.). This can reduce the problems caused by the unwelded part Q.

For example, the bag making apparatus may include a scale (not illustrated) fixed to the main frame <NUM> of the bag making apparatus to extend along the feed path. The scale may indicate, for example, the distance from the cross cut position Pr of the cut device <NUM> as a reference position to a position upstream of the cross cut position Pr. The scale may indicate a rough position or distance. In addition, the accuracy of the indication may be increased within the movable range of the welding device <NUM>.

An object <NUM> to be detected (<FIG>) is mounted on the support arrangement <NUM> (e.g., the side frame <NUM>) at the same position as the pressure position P<NUM> with respect to the directions Y<NUM> and Y<NUM>. A sensor <NUM> (<FIG>) for detecting the position of the welding device <NUM> is fixed to the main frame <NUM>. For example, the sensor <NUM> may be attached to the main frame <NUM>, the rack <NUM>, or the scale. The sensor <NUM> is capable of detecting the object <NUM>.

When the sensor <NUM> detects the object <NUM> during the movement of the units <NUM> and <NUM> by the movement device <NUM>, the control device <NUM> determines the position of the welding device <NUM> on the feed path at the time of detecting, specifically, any one of the positions P<NUM> to P<NUM>, based on the detection by the sensor <NUM>. For example, the control device <NUM> can determine the distance from the cross cut position Pr to any one of the positions P<NUM> to P<NUM>, and may indicate this on the indicator <NUM>.

Alternative to the above, the movement device <NUM> may be configured such that the sensor <NUM> is supported by the support arrangement <NUM> to read the scale or the object <NUM> on the main frame <NUM>. The sensor <NUM> may be an optical sensor (including a camera), a magnetic sensor, or the like. The configuration of the object <NUM> is selected according to the type of sensor <NUM>.

A reference position may be defined within the movable range of the welding device <NUM> on the feed path. A digital sensor for detecting the position of the welding device <NUM> may be used to determine the position of the welding device <NUM> with reference to this reference position. This allows for determining the position of the welding device <NUM> with high accuracy.

Examples of specific positioning of the units <NUM> and <NUM> are as follows.

The units <NUM> and <NUM> may be positioned with respect to the seal device <NUM> such that the seal device <NUM> can seal the sheet panel <NUM> over the aforementioned entire unwelded area q. This causes the sheet panel <NUM> and the strip member <NUM> to be sealed to each other in the unwelded area q, which results in solving the problems (e.g., leakage) caused by the unwelded part Q.

<FIG> partially illustrates the seal position S where the seal device <NUM> (its seal members <NUM> in the implementation) seals. In <FIG>, the part indicated with hatching is the unwelded area Q, and the area q in the unwelded area Q is the aforementioned unwelded area. As illustrated in <FIG>, the seal device <NUM> and the welding device <NUM> should be positioned such that an unwelded center qc of an unwelded area q is located on the seal width center Sc of the seal position S every pause phase of the intermittent feed cycle.

Each upstream device is typically positioned with reference to the most downstream cut device <NUM>, i.e., the cross cut position Pr. Thus, the seal device <NUM> and the welding device <NUM> (the units <NUM> and <NUM>) may be adjusted with respect to the cross cut position Pr, so that the seal device <NUM> and the welding device <NUM> are positioned with respect to each other.

As described above, the seal device <NUM> and the cut device <NUM> have been properly positioned in advance. That is, the distance along the feed path between the cross cut position Pr and the seal width center Sc is an integer multiple of the feed pitch.

As is clear from <FIG> and the above description, the unwelded center qc corresponds to the position P<NUM> within the welding device <NUM>. This position P<NUM> is the midpoint between the pressure position P<NUM> and the downstream end P<NUM> of the irradiation position R. Therefore, if the distance along the feed path from the cross cut position Pr to the position P<NUM> becomes an integer multiple of the feed pitch, the distance along the feed path from the seal width center Sc to the position P<NUM> also becomes an integer multiple of the feed pitch.

The units <NUM> and <NUM> should be adjusted with respect to the cut device <NUM> using the movement device <NUM> such that the distance between the cross cut position Pr and the position P<NUM> is an integer multiple of the feed pitch. Consequently, the units <NUM> and <NUM> are adjusted with respect to the seal device <NUM>.

The irradiation angle θ and the distance of the section P<NUM>-P<NUM> are known because they have been preset. The control device <NUM> is able to determine the position P<NUM> using the length of the unwelded area q obtained in advance and the configuration for detecting the pressure position P<NUM>, as described above.

For the manual movement device <NUM> in <FIG>, the control device <NUM> may indicate the information regarding the positional relationship between the cross cut position Pr and the position P<NUM> on the indicator <NUM> based on the determined position P<NUM>. For example, the control device <NUM> may indicate, on the indicator, the distance of the section Pr-Pi along the feed path with reference to the cross-cut position Pr.

The control device <NUM> may also indicate, on the display as the indicator <NUM>, the offset distance of the position P<NUM> relative to a separation position which is spaced upstream away from the cross cut position Pr by an integer multiple of the feed pitch along the feed path. As a specific example, the offset distance may be indicated on the display using +/- when the position P<NUM> is offset upstream from the separation position, while it may be indicated using -/+ when the position P<NUM> is offset downstream. This makes it easier for operators to know whether they should move the units <NUM> and <NUM> upstream or downstream.

For the automatic type of movement device <NUM> in <FIG>, the control device <NUM> may control the movement device <NUM> (drive source <NUM>) based on the detection by the sensor <NUM> to automatically position the units <NUM> and <NUM> to make the distance between the cross cut position Pr (seal width center Sc) and the position P<NUM> an integer multiple of the feed pitch.

Where a plain sheet panel <NUM> is used, the adjustment may be carried out, for example, as follows. There is a considerable distance between the cut device <NUM> and the welding device <NUM>. The sheet panel <NUM> which is made of material such as film can stretch or shrink depending on environmental conditions including temperature and humidity. However, for a plain sheet panel <NUM>, if the feed pitch is fixed and the distance of the section Pr-P<NUM> is adjusted to an integer multiple of the feed pitch, the unwelded center qc will not deviate significantly from the cross cut position Pr.

For example, an operator may visually check the positional relationship between the unwelded center qc and the seal width center Sc to confirm misalignment. The operator can then operate the manual movement device <NUM> in <FIG> to cancel the misalignment.

For the configurations that include the aforementioned digital type sensor, it is possible to determine the exact distance of the section Pr-P<NUM>, which allows for more accurate positioning. When the seal width center Sc and the unwelded center qc are misaligned due to stretch or shrink of the sheet panel <NUM>, an operator can visually check this misalignment and then fine-adjust it using the movement device <NUM>.

As illustrated in <FIG>, in making the bags <NUM> each with the zipper <NUM>, a crushed section <NUM> with a width greater than the width of the cross sealed section <NUM> may be formed to completely melt and closely adhere the male and female members <NUM> and <NUM> of the zipper <NUM>. This crushed section <NUM> ensures the sealablity of the bag <NUM> (see Patent document <NUM>).

In this case, as illustrated in <FIG>, the bag making apparatus may include a point seal device <NUM> in the intermittent feed zone <NUM>, which seals the sheet panel <NUM> and the zipper (strip member) <NUM> in a point-like manner to form a crushed section <NUM>. The point seal device <NUM> is disposed, for example, downstream of the welding device <NUM> and upstream of the seal device <NUM>.

The unwelded area q may be completely contained in the crushed section <NUM> formed by the point seal device <NUM>. For this purpose, a sensor <NUM> such as a camera for detecting the positions of the unwelded areas q is arranged to be spaced upstream away from the point seal device <NUM> by a distance v. Since the unwelded area q is optically different from the surrounding area thereof, the sensor <NUM> can optically detect the unwelded area q. The control system <NUM> determines the position of the unwelded area q based on the detection by the sensor <NUM>.

For example, the control device <NUM> may process (image-process) the data obtained from the sensor <NUM> to determine the position of the unwelded area q, thereby determining the distance between the area q and the point seal position of the point seal device <NUM>. The control device <NUM> then compares this determined distance to a predetermined threshold value to determine whether the welding device <NUM> (units <NUM>, <NUM>) should be moved in the direction Y<NUM> or Y<NUM>, and also determines the distance by which it should be moved. The control device <NUM> may then indicate the information regarding the determined direction and the determined distance on the indicator <NUM>. An operator adjusts the units <NUM> and <NUM> with respect to the point seal device <NUM> using the movement device <NUM> considering that information, such that the entire unwelded area q is contained in the crushed section <NUM>. The control device <NUM> may do that automatically by controlling the movement device <NUM> based on the detection by the sensor <NUM>.

The control device <NUM> may indicate the image pertaining to the data acquired from the sensor <NUM> on the indicator <NUM>. If it is difficult to automatically identify the unwelded part Q using the sensor <NUM>, an operator may see the above image displayed on the indicator <NUM> to determine the position of the unwelded part Q, and manually operate the movement device <NUM>.

The sensor <NUM> may be supported, for example by the main frame <NUM>, to be displaceable in the directions Y<NUM> and Y<NUM>. This allows the position of the sensor <NUM> and thus the distance v to be adjusted according to the dimensions of the bags <NUM> to be made.

A sheet panel <NUM> with print patterns may be used. The print patterns are repeatedly printed on the sheet panel <NUM>. In this case, the units <NUM> and <NUM> may be positioned based the print pattern(s), especially the mark M (<FIG>), such as a register mark included in each print pattern.

For example, as illustrated in <FIG>, a sensor <NUM> for detecting the positions of the print patterns is placed upstream of and in the vicinity of the pressure rollers <NUM>. Specifically, the sensor <NUM> is capable of detecting the marks M (in the implementation, the register marks). The sensor <NUM> is configured to be movable together with the units <NUM> and <NUM> by the aforementioned movement device <NUM>. For example, the sensor <NUM> may be supported by the support arrangement <NUM>. The sensor <NUM> may be displaceably supported by the support arrangement <NUM>, so that it is possible to change its position according to the dimensions of the bags <NUM>.

The distance along the feed path for the sheet panel <NUM> between the detection position of the sensor <NUM> and the pressure position P<NUM> is known. Therefore, the control device <NUM> can determine the relative positional relationship between the position of the print pattern (mark M) and the unwelded area q based on the detection by the sensor <NUM>.

For example, as illustrated in <FIG>, if the design distance on the sheet panel <NUM> from the position Pr' where the sheet panel <NUM> is to be cross-cut, to the edge Ms of the mark M is <NUM> and the length of the unwelded area q (the distance of the section P<NUM>-P<NUM>) is <NUM>, the distance from the detection position of the sensor <NUM> to the pressure point P<NUM> should be <NUM> (= <NUM> + <NUM>/<NUM>). This ensures, combined with the adjustment of the positional relationship between the cross cut position Pr and the mark M using the sensor etc. described below, that the sheet panel <NUM> is cross-cut at the unwelded center qc if the sensor <NUM> detects the edge Ms of the mark M during the pause phase of the intermittent feed cycle.

The sensor <NUM> and the pair of pressure rollers <NUM> have been adjusted in advance to the above positional relationship. If the sensor <NUM> does not detect the edge Ms during the puase phase of the intermittent feed cycle, the distance between the mark M and the unwelded center qc is considered to be longer than the design distance. Therefore, if so, the control device <NUM> contorlls the movement device <NUM> to move the units <NUM> and <NUM> and the sensor <NUM> slightly upstream (in the direction Y<NUM>) during the next feed phase.

In contrast, if the sheet panel <NUM> is paused after the sensor <NUM> detects the edge Ms, the distance between the mark M and the unwelded center qc is considered to be shorter than the design distance. Therefore, if so, the controll device <NUM> contorlls the movement device <NUM> to move the units <NUM> and <NUM> and the sensor <NUM> slightly downstream (in the direction Y<NUM>) during the next feed phase.

Such positioning of the units <NUM> and <NUM> is repeated every intermittent feed cycle. Therefore, it is possible to make sure that the cross cut position Pr and the unwelded center qc almost always align with each other during cross cutting.

If the cross cut position Pr and the unwelded center qc are significantly misaligned during cross cutting due to unforeseen circumstances, they can fail to be easily recovered even after the above positioning is repeated. In this case, the control device <NUM> may indicate warning on the indicator <NUM>.

As illustrated in <FIG>, the sensor <NUM> for detecting the positions of the print patterns may be disposed upstream of and in the vicinity of the cut device <NUM>. The sensor <NUM> is configured to detect the marks M in the same way as the aforementioned sensor <NUM>. The cross cut position Pr and the detection position of the sensor <NUM> are in the same positional relationship as the pressure position P<NUM> and the sensor <NUM>.

If the sensor <NUM> does not detect the edge Ms during the pause phase of the intermittent feed cylce, the control device <NUM> controls the feed device <NUM> to slightly increase the feed pitch of the next intermittent feed. In contrast, if the sheet panel <NUM> is paused after the sensor <NUM> detects the edge Ms, the control device <NUM> controls the feed device <NUM> to slightly reduce the feed pitch of the next intermittent feed.

Such pitch adjustment is repeated every intermittent feed cycle. As a result of the above processes, both the positional relationship between the mark M and the position P<NUM> of the welding device <NUM> (corresponding to the unwelded center qc) and the positional relationship between the mark M and the cross cut position Pr of the cut device <NUM> are maintained in the design positional relationship. Therefore, it is guaranteed that the unwelded center qc on the sheet panel <NUM> substantially matches the cross cut position Pr during cross-cuting. This and the aforementioned adjustment of the units <NUM> and <NUM> using the sensor <NUM> may be carried out independently and simultaneously.

The distance from the seal width center Sc of the seal device <NUM> to the cross cut position Pr of the cut device <NUM> in the above implementations has been adjusted in advance to be an integer multiple of the feed pitch. Alternatively, the positional relationship between the seal width center Sc and the sheet panel <NUM> may be adjusted using sensors in the same way. For example, the bag making apparatus detects the position of the mark M on the sheet panel <NUM> during the pause phase of the intermittent feed cycle of the sheet panel <NUM> using a sensor located in the vicinity of the seal device <NUM>. Then, if the mark M has advanced beyond the design position, the bag making apparatus decreases the amount of the next intermittent feed of the sheet panel <NUM>, or moves the seal members of the seal device <NUM> (e.g., the heat seal bars in the implementation) (and thus the seal width center Sc of the seal device <NUM>) downstream. In contrast, if the position of the mark M is delayed relative to the design position, the bag making apparatus increases the amount of the next intermittent feed or moves the seal members (seal width center Sc) upstream.

The method of adjusting each device in the bag making apparatus and/or the feed pitch of the sheet panel <NUM> may be determined as appropriate, taking into consideration the overall configuration of the bag making apparatus.

In yet another implementation, at least one sensor may be provided for detecting the positions of the print patterns and for detecting the positions of the unwelded parts Q. Based on the detection by the sensor, the control device <NUM> may determine the positional relationship between the print pattern and the unwelded part and indicate the information regarding this on the indicator <NUM>, or control the movement device <NUM> to position the units <NUM> and <NUM>.

For example, an optical sensor such as a camera is used as the sensor. The control device <NUM> image-processes the data from this sensor to determine the relative positional relationship between the mark M and the unwelded part Q (unwelded area q). The control device <NUM> may then indicate the information regarding the relative positional relationship on the indicator <NUM>. Alternatively, the control device <NUM> may control the movement device <NUM> based on the relative positional relationship to position the units <NUM> and <NUM> in the same way as the above implementations. Of course, when it is difficult to automatically identify the unwelded part Q as described above, an operator may visually check the image indicated on the indicator <NUM> to determine the position of the unwelded part Q, and manually operate the movement device <NUM>.

The sensor for detecting the positions of the print patterns and the sensor for detecting the positions of the unwelded parts Q may be separate components.

As described above, some implementations make the mutual distance among the welding device <NUM> (its position P<NUM>), the seal device <NUM> (its seal width center Sc), and the cut device <NUM> (its cross cut position Pr) an integer multiple of the feed pitch. This allows the unwelded part Q (unwelded area q), which is generated in laser welding, to be completely contained within the cross sealed section <NUM> and thus be eliminated, and the cut device <NUM> to cross-cut the sheet panel <NUM> at the width center of the cross sealed section <NUM>.

In the implementations that use a sheet panel <NUM> with print patterns, the positional relationship between the sheet panel <NUM> and the devices <NUM>, <NUM> and <NUM> is adjusted at the process positions of the respective devices <NUM>, <NUM>, and <NUM> based the print pattern(s) (mark M) to align the unwelded center qc, the width center of the cross sealed section <NUM>, and the position Pr' where it is to be cross-cut, among each other. This also allows for the disappearance of the unwelded parts Q (unwelded areas q) and accurate cross-cutting at the width center of each cross sealed section <NUM>. This is particularly effective in bag making using the sheet panel <NUM> made of highly stretchable mono-material such as polyethylene, polypropylene and so on.

The implementations have been described above.

The movement device <NUM> and its support arrangement <NUM>, etc., may be modified depending on bag making methods. For example, when two separate sheet panels are used as in Patent documents <NUM> and <NUM>, the base shaft <NUM>, etc. may be supported by both side frames inteated of only one side frame <NUM>. This is also applicable to multi-line bag making.

The strip member <NUM> in the above implementations is the zipper which includes the male member and the female member fitted to each other. Alternatively, the strip member <NUM> may be, for example, a male member of a zipper, a female member of a zipper, a male member of a hook-and-loop fastener, a female member of a hook-and-loop fastener, a hook-and-loop fastener (which includes a male member and a female member engaged with each other), an adhesive tape, a seal tape, a tape-like reinforcing member, a tape-like decorative member, a tape-like header of a bag, and so on.

For welding, the sheet panel <NUM> may be irradiated with the laser beam <NUM> to be melted. In this case, the light absorbing layer is provided not on the strip member <NUM> but on the sheet panel <NUM>.

Claim 1:
A bag making apparatus for successively making bags (<NUM>) from a continuous sheet panel (<NUM>) and a continuous strip member (<NUM>), the bag making apparatus comprising:
a feed device (<NUM>) configured to intermittently feed the sheet panel (<NUM>) and the strip member (<NUM>) in a longitudinal direction of the sheet panel (<NUM>) and the strip member (<NUM>);
a welding device (<NUM>) configured to weld the sheet panel (<NUM>) and the strip member (<NUM>) to each other in a zone where the sheet panel (<NUM>) is intermittently fed by the feed device (<NUM>); and
a cut device (<NUM>) disposed downstream of the welding device (<NUM>) and configured to cross-cut the sheet panel (<NUM>) and the strip member (<NUM>) in a width direction of the sheet panel (<NUM>) during every intermittent feed cycle,
the welding device (<NUM>) comprising:
a pressure unit (<NUM>) comprising a pair of pressure rollers for pressurizing the sheet panel (<NUM>) and the strip member (<NUM>) superposed on each other during a feed phase of an intermittent feed cycle; and
a laser unit (<NUM>) configured to irradiate the sheet panel (<NUM>) or the strip member (<NUM>) with a laser beam (<NUM>) at an irradiation position (R) spaced upstream away from a pressure position (P<NUM>) of the pressure unit (<NUM>) to melt the sheet panel (<NUM>) or the strip member (<NUM>) using the laser beam (<NUM>),
wherein a part of the sheet panel (<NUM>) or the strip member (<NUM>) irradiated with the laser beam (<NUM>) returns to a non-molten state due to decrease in temperature in a section from the irradiation position (R) to the pressure position (P<NUM>) during a pause phase of an intermittent feed cycle, so that an unwelded part (Q) is generated every intermittent feed cycle,
the bag making apparatus further comprising:
a movement device (<NUM>) for moving the pressure unit (<NUM>) and the laser unit (<NUM>) together upstream and downstream while maintaining a relative positional relationship between the pressure position (P<NUM>) and the irradiation position (R); and
a control device (<NUM>) configured to control the movement device (<NUM>) to move the pressure unit (<NUM>) and the laser unit (<NUM>) together upstream and downstream during a pause phase of an intermittent feed cycle, thereby adjusting a position on the sheet panel (<NUM>) where the unwelded part (Q) is generated, in the longitudinal direction of the sheet panel (<NUM>).