Blister packaging machine

A blister packaging machine includes: a pocket portion forming unit that forms a pocket portion having a bottom portion and a side portion, in a belt-like container film, and adjusts balance between a thickness of the bottom portion and a thickness of the side portion; an illumination device that is disposed on a downstream side of the pocket portion forming unit, and irradiates the pocket portion with an electromagnetic radiation; an imaging device that is disposed on a side opposite to the illumination device across the container film, and obtains transmitted image data based on the electromagnetic radiation transmitted through the pocket portion; a side portion state detector that detects a state of the thickness of the side portion based on the transmitted image data; and a controller that controls an operation of the pocket portion forming unit.

BACKGROUND

Technical Field

The present invention relates to a blister packaging machine configured to manufacture a blister sheet that contains a predetermined content therein.

Description of Related Art

A blister sheet includes a container film that is provided with pocket portions formed to respectively contain contents such as tablets or capsules and a cover film that is mounted to the container film to close openings of the pocket portions.

The blister sheet is manufactured by a blister packaging machine. The blister packaging machine includes a pocket portion forming unit configured to form pocket portions in a belt-like container film; a filling unit configured to fill contents into the pocket portions; a mounting unit configured to mount a belt-like cover film to the container film; and a punching unit configured to punch out a belt-like blister film obtained by mounting the cover film to the container film, so as to obtain the blister sheet.

The pocket portion forming unit may employ a plate-type pressure forming method or a plug forming method. The plate-type pressure forming method sandwiches a heated and softened container film between a first mold having recesses in a shape corresponding to the pocket portions and a second mold having holes for the air supply and supplies the high-pressure air to the holes of the second mold to expand the container film toward the recesses, so as to form the pocket portions. The plug forming method sandwiches a heated and softened container film between a first mold and a second mold and protrudes plugs of a convex shape provided in the second mold to be inserted into holes provided in the first mold, so as to form pocket portions in a shape corresponding to the plugs.

A recently proposed configuration of the pocket portion forming unit employs both the forming methods described above, with a view to reducing the wall thickness of the bottom portion in the pocket portion (as described in, for example, Patent Literature 1). This pocket portion forming unit includes a first mold having holes for the supply of the air (air supply holes); a second mold having insertion holes opposed to the air supply holes across a container film; and plugs arranged to lift up and down relative to the insertion holes.

A procedure of forming the pocket portions by this pocket portion forming unit first sandwiches a heated and softened container film between the two molds and places the plugs at a predetermined intermediate stop position such that end surfaces of the plugs are away from the container film. The procedure subsequently supplies the high-pressure air into the air supply holes, so as to expand predetermined forming regions of the pocket portions in the container film toward the plugs. The predetermined forming regions are expanded until the predetermined forming positions are supported by the plugs. The procedure subsequently moves the plugs and causes the predetermined forming regions to be pressed by the plugs toward an opposite direction to the expanding direction. The procedure eventually moves the plugs to a position where the plugs are protruded from the second mold and reverses the expanding direction of the predetermined forming regions to form the pocket portions.

PATENT LITERATURE

The pocket portion forming unit described above is, however, likely to unintentionally destroy the balance between the thickness of the bottom portion and the thickness of the side portion in the pocket portion in the course of production of the blister sheet. As a result, this is likely to cause part of the pocket portion to be extremely thinned and to decrease the gas barrier property of the pocket portion. The side portion is generally made thinner than the bottom portion.

SUMMARY

One or more embodiments of the present invention provide a blister packaging machine that suppresses balance between the thickness of a bottom portion and the thickness of a side portion from being unintentionally destroyed and accordingly enables a pocket portion having good gas barrier property to be formed more reliably for a longer time period.

The following describes functions and advantageous effects of one or more embodiments.

A blister packaging machine according to one or more embodiments comprises a pocket portion forming unit configured to form a pocket portion that includes a bottom portion and a side portion, in a conveyed belt-like container film. The pocket portion forming unit is configured to adjust balance between thickness of the bottom portion and thickness of the side portion. The blister packaging machine further comprises an illumination unit (illumination device) placed downstream of the pocket portion forming unit and configured to irradiate at least the pocket portion with predetermined electromagnetic radiation; an imaging unit (imaging device) placed on a side opposite to the illumination unit across the container film and configured to obtain at least transmitted image data based on the electromagnetic radiation transmitted through the pocket portion; a side portion state detecting unit configured to detect a state with regard to the thickness of the side portion, based on the transmitted image data obtained by the imaging unit; and a controller configured to control operation of the pocket portion forming unit, based on a result of detection by the side portion state detecting unit.

The state with regard to the thickness of the side portion may be the thickness of the side portion itself (for example, the average thickness of the side portion or may be the state of a factor that varies with a variation in thickness of the side portion (for example, the transmittance of the electromagnetic radiation).

In the blister packaging machine of one or more embodiments, the side portion state detecting unit detects the state with regard to the thickness of the side portion in the pocket portion, based on the transmitted image data obtained by the imaging unit. The controller then performs feedback control of the operation of the pocket portion forming unit, based on the detected state with regard to the thickness of the side portion, so as to adjust balance between the thickness of the bottom portion and the thickness of the side portion in the formed pocket portion. Even when the balance between the thickness of the bottom portion and the thickness of the side portion is unintentionally destroyed in the course of production, this configuration automatically corrects the destroyed balance and thereby effectively prevents excessive wall thinning of the side portion. As a result, this configuration enables the pocket portion having good gas barrier property to be formed more reliably for a longer time period.

In the blister packaging machine according to one or more embodiments, the side portion state detecting unit may detect the state with regard to the thickness of the side portion, based on a state with regard to the thickness of the bottom portion in the transmitted image data.

A configuration employable to detect the state with regard to the thickness of the side portion may directly recognize the state of the side portion itself. In this configuration, there is a need to recognize the state of the entire circumference of the side portion by taking into account the gas barrier property. It is, however, likely to take a relatively long time for recognizing the state of the entire circumference of the side portion. This may fail to sufficiently respond to the high-speed production of a blister sheet.

There is a correlation between the thickness of the bottom portion and the thickness of the side portion. The thick bottom portion provides the thin side portion, whereas the thin bottom portion provides the thick side portion. In the blister packaging machine according to one or more embodiments, the side portion state detecting unit takes advantage of this correlation and detects the state with regard to the thickness of the side portion, based on the state with regard to the thickness of the bottom portion in the transmitted image data. Accordingly, this configuration enables information required for the thickness control of the pocket portion to be obtained in a shorter time period and sufficiently responds to the high-speed production of the blister sheet.

The bottom portion of the pocket portion is generally arranged to be substantially parallel to a non-forming region (flat region) of the pocket portion in the container film. When the imaging unit is placed such that an optical axis of a lens is perpendicular to the non-forming region (flat region), the obtained transmitted image data is likely to have a difference in transmission of the electromagnetic radiation with regard to an area corresponding to the bottom portion. Accordingly, this configuration enables the state with regard to the thickness of the bottom portion to be more accurately recognized and thereby enables the state with regard to the thickness of the side portion to be more accurately detected. As a result, this configuration ensures the thickness control of the pocket portion with the higher accuracy.

In the blister packaging machine according to one or more embodiments, the container film may be formed from a transparent resin material, and the illumination unit may be configured to emit ultraviolet light as the electromagnetic radiation.

The ultraviolet light has the lower transmittance and is more unlikely to transmit through the transparent container film, compared with visible light. The configuration according to one or more embodiments thus enables the state with regard to the thickness of the bottom portion and the state with regard to the thickness of the side portion to be more accurately detected, based on the transmitted image data. Accordingly, this configuration may ensure the thickness control of the pocket portion.

In the blister packaging machine according to one or more embodiments, the pocket portion forming unit may comprise a first mold having a predetermined first hole; a second mold having a second hole that is opposed to the first hole across the container film; a pressing element placed to be movable back and forth relative to the second hole; and an expanding unit configured to perform a film expanding operation that is at least one of supplying a predetermined gas to the first hole and supplying a negative pressure to the second hole.

The pocket portion forming unit may be configured to perform a process of sandwiching the container film between the two molds, placing the pressing element at an intermediate stop position set in advance to be away from the container film, and performing the film expanding operation to expand a predetermined forming region of the pocket portion in the container film toward the pressing element; and a process of pressing the expanded predetermined forming region toward the first hole by the pressing element, so as to form the pocket portion.

The pocket portion forming unit according to one or more embodiments performs the film expanding operation to expand the predetermined forming region of the pocket portion until the predetermined forming region is supported by the pressing element. Accordingly, changing the intermediate stop position of the pressing element changes the stretch amount of the predetermined forming region and thereby adjusts the balance between the thickness of the bottom portion and the thickness of the side portion in the pocket portion.

More specifically, setting the intermediate stop position of the pressing element to have a relatively large distance between the container film and the pressing element provides a relatively large stretch amount of the predetermined forming region of the pocket portion in the container film in the process of the film expanding operation, so as to make the predetermined forming region thin as a whole. The predetermined forming region is then pressed by the pressing element, so that the pocket portion is formed with an area corresponding to the bottom portion kept thin. As a result, the formed pocket portion has a relatively thin bottom portion and a relatively thick side portion.

Setting the intermediate stop position of the pressing element to have a relatively small distance between the container film and the pressing element, on the other hand, provides a relatively small stretch amount of the predetermined forming region in the process of the film expanding operation, so as to make the predetermined forming region thick as a whole. The predetermined forming region is then pressed by the pressing element, so that the pocket portion is formed with the area corresponding to the bottom portion kept thick and an area corresponding to the side portion stretched. As a result, the formed pocket portion has a relatively thick bottom portion and a relatively thin side portion.

As described above, the pocket portion forming device adjusts the balance between the thickness of the bottom portion and the thickness of the side portion in the pocket portion by changing the intermediate stop position of the pressing element. This configuration accordingly enables the balance adjustment of the thickness to be performed extremely easily.

The blister packaging machine according to one or more embodiments may further comprise a filling unit (filling device) placed downstream (is disposed on a downstream side) of the illumination unit and configured to fill a predetermined content into the pocket portion; and a filling controller configured to control an operation of the filling unit, based on the result of detection of the side portion state detecting unit and change over between permission and prohibition of filling of the content into the pocket portion.

In the blister packaging machine of one or more embodiments, when the side portion is extremely thin, the filling controller controls the filling unit not to fill the content into the pocket portion. In the case where the blister sheet is discarded due to the extreme thinness of the side portion, this configuration prevents the content from being discarded together with the blister sheet and thereby reduces the waste of the content. This configuration also does not require a troublesome work of, for example, taking the filled content out of the pocket portion for recycle of the content and accordingly enhances the productivity.

The blister packaging machine according to one or more embodiments may further comprise a filling unit placed downstream of the pocket portion forming unit and configured to fill a predetermined content into the pocket portion. The illumination unit may irradiate at least the pocket portion and the content with the electromagnetic radiation in downstream of the filling unit. The blister packaging machine may further comprise a content quality determination unit configured to determine quality of the content, based on the transmitted image data obtained by the imaging unit.

The configuration of one or more embodiments performs just not detection of the state with regard to the thickness of the side portion but determination of the quality of the content, based on the transmitted image data obtained by the imaging unit. This configuration accordingly simplifies the blister packaging machine and reduces an increase in manufacturing and other costs of the blister packaging machine.

DETAILED DESCRIPTION

The following describes embodiments with reference to drawings. A PTP sheet1that is the blister sheet is described first. As shown inFIG. 1andFIG. 2, the PTP sheet1includes a container film3provided with a plurality of pocket portions2, and a cover film4mounted to the container film3such as to close the respective pocket portions2. One tablet5as a content is placed in each of the pocket portions2.

The pocket portion2has a bottom portion2aand a side portion2b. The bottom portion2ais a region that forms a bottom of the pocket portion2and is configured to be substantially parallel to a flat non-forming portion3bthat is a region of the container film3where the pocket portions2are not formed. According to one or more embodiments, the bottom portion2ais a region of the pocket portion2that is configured to overlap with the tablet5along a direction perpendicular to the non-forming portion3b. The side portion2bis a cylindrical region that is located between the bottom portion2aand the non-forming portion3b. According to one or more embodiments, the side portion2bis a region of the pocket portion2other than the bottom portion2a.

The container film3is made of a transparent thermoplastic resin material, for example, PP (polypropylene) or PVC (polyvinyl chloride). The cover film4is, on the other hand, made of an opaque material (for example, aluminum foil) with a sealant comprised of, for example, a polypropylene resin, applied on a surface thereof.

The PTP sheet1is formed in an approximately rectangular shape in a plan view and is configured such that two pocket arrays are formed in a sheet short side direction and that each pocket array includes five pocket portions2arranged along a sheet longitudinal direction. Accordingly, a total of ten pocket portions2are formed. The number and the layout of the pocket portions2may, however, be changed.

The PTP sheet1is manufactured by punching sheets from a belt-like PTP film6(shown inFIG. 3) that is formed from the belt-like container film3and the belt-like cover film4.

The following describes the general configuration of a PTP packaging machine11serving as the blister packaging machine to manufacture the PTP sheet1described above, with reference toFIG. 5.

A film roll of the belt-like container film3is wound in a roll form on a most upstream side of the PTP packaging machine11. A pullout end of the container film3wound in the roll form is guided by a guide roll13. The container film3is then laid on an intermittent feed roll14placed (disposed) on a downstream side of the guide roll13. The intermittent feed roll14is coupled with a motor rotating in an intermittent manner, so as to convey the container film3intermittently.

A heating device15and a pocket portion forming device16serving as the pocket portion forming unit are sequentially placed along the conveyance path of the container film3between the guide roll13and the intermittent feed roll14. In the state that the container film3is heated to be relatively soft by the heating device15, the plurality of pocket portions2are formed simultaneously at predetermined positions of the container film3by the pocket portion forming device16. Formation of the pocket portions2is performed during an interval between conveying operations of the container film3by the intermittent feed roll14. The configuration of the heating device15and the pocket portion forming device16will be described later.

A formation state detecting device21is placed downstream of the pocket portion forming device16to be arranged between the guide roll13and the intermittent feed roll14. The formation state detecting device21is a device configured to detect the state with regard to the thickness of the formed pocket portion2. The configuration of the formation state detecting device21will be described later.

The container film3fed from the intermittent feed roll14is sequentially laid on a tension roll18, a guide roll19and a film receiving roll20in this order. The film receiving roll20is coupled with a motor rotating at a fixed speed, so as to continuously convey the container film3at a fixed speed. The tension roll18is configured to pull the container film3in a direction of applying tension by an elastic force. This configuration prevents a slack of the container film3due to a difference between the conveying operation by the intermittent feed roll14and the conveying operation by the film receiving roll20and constantly keeps the container film3in the state of tension.

A tablet filling device22is placed along the conveyance path of the container film3between the guide roll19and the film receiving roll20. The tablet filling device22serves as the filling unit to automatically fill the tablets5into the pocket portions2. The tablet filling device22opens a shutter at every predetermined time interval to drop the tablet5, in synchronism with the conveying operation of the container film3by the film receiving roll20. Each of the pocket portions2is filled with the tablet5by this shutter opening operation. The operations of the tablet filling device22are controlled by a filling control device82described later.

A film roll of the belt-like cover film4is also wound on a roll form and is placed on a most upstream side.

A pullout end of the cover film4wound in the roll form is guided by a guide roll24to a heating roll25. The heating roll25is pressed against to be in contact with the film receiving roll20described above. The container film3and the cover film4are accordingly fed into between the two rolls20and25. The container film3and the cover film4pass through between the two rolls20and25in the heated and pressed contact state, so that the cover film4is mounted to the container film3such as to close the respective pocket portions2. This series of operations manufactures the PTP film6with the tablets5filled in the respective pocket portions2.

The PTP film6fed from the film receiving roll20is sequentially laid on a tension roll27and an intermittent feed roll28in this order. The intermittent feed roll28is coupled with a motor rotating in an intermittent manner, so as to convey the PTP film6intermittently. The tension roll27is configured to pull the PTP film6in a direction of applying tension by an elastic force. This configuration prevents a slack of the PTP film6due to a difference between the conveying operation by the film receiving roll20and the conveying operation by the intermittent feed roll28and constantly keeps the PTP film6in the state of tension.

The PTP film6fed from the intermittent feed roll28is sequentially laid on a tension roll31and an intermittent feed roll32in this order. The intermittent feed roll32is coupled with a motor rotating in an intermittent manner, so as to convey the PTP film6intermittently. The tension roll31is configured to pull the PTP film6in a direction of applying tension by an elastic force and thereby serves to prevent a slack of the PTP film6between these intermittent feed rolls28and32.

A slit formation device33and a stamping device34are sequentially placed along the conveyance path of the PTP film6between the intermittent feed roll28and the tension roll31. The slit formation device33serves to form a cutting slit at predetermined positions of the PTP film6. The stamping device34serves to stamp a mark at predetermined positions of the PTP film6(for example, in tag portions).

The PTP film6fed from the intermittent feed roll32is sequentially laid on a tension roll35and a continuous feed roll36in this order on a downstream side of the intermittent feed roll32. A sheet punching device37is placed along the conveyance path of the PTP film6between the intermittent feed roll32and the tension roll35. The sheet punching device37serves to punch out the outer periphery of each portion of the PTP film6in the unit of PTP sheet1.

The respective PTP sheets1punched out by the sheet punching device37are conveyed by an extraction conveyor38and are temporarily accumulated in a finished product hopper39. When a defective signal is input from the filling control device82described later into a defective sheet discharge mechanism40that is configured to selectively discharge the PTP sheet1, the PTP sheet1determined as defective is separately discharged by the defective sheet discharge mechanism40and is transferred to a non-illustrated defective hopper.

A cutting device41is placed on a downstream side of the continuous feed roll36. A scrap portion42that remains in a belt-like form after punching out by the sheet punching device37is guided by the tension roll35and the continuous feed roll36described above and is subsequently led to the cutting device41. A driven roll is pressed against to be in contact with the continuous feed roll36, so that the scrap portion42is placed and conveyed between the driven roll and the continuous feed roll36. The cutting device41serves to cut the scrap portion42into predetermined dimensions. The cut pieces of the scrap portion42are accumulated in a scrap hopper43and are disposed separately.

Each of the rolls14,19,20,28,31,32and the like described above is arranged such that the roll surface is opposed to the pocket portions2. The surface of each of the rolls14and the like has recesses that are formed to place the pocket portions2therein. This configuration basically suppresses the pocket portions2from being crushed. The feeding operation with the pocket portions2placed in the recesses of each of the rolls14and the like achieves the reliable intermittent feed and continuous feed.

The following describes the configuration of the heating device15and the pocket portion forming device16with reference toFIG. 7.

The heating device15includes an upper heater plate15aand a lower heater place15b. The respective heater plates15aand15bare configured to be heated by a non-illustrated heater. The respective heater plates15aand15bare arranged across the conveyance path of the container film3to be movable in a direction of coming closer to or going away from the container film3.

The heater plates15aand15brespectively have a plurality of protrusions15cand15dprovided at positions corresponding to predetermined forming regions of the pocket portions2in the container film3. As the respective heaters15aand15bcome closer to the intermittently fed container film3during a temporary stop of the container film3, the container film3is sandwiched between the protrusions15cand15dto be heated and softened partly (at spots). According to one or more embodiments, contact regions of the protrusions15cand15dthat come into contact with the container film3are formed to be slightly smaller than the planar shape of the pocket portions2.

The pocket portion forming device16includes a lower mold61as the second mold and an upper mold71as the first mold. The lower mold61is fixed to a support base63in a stationary state via a cylindrical lower mold chamber62. The lower mold61also has a plurality of insertion holes64at positions corresponding to the positions of the pocket portions2. According to one or more embodiments, the insertion hole64corresponds to the second hole.

A plurality of through holes is formed in the support base63, and rod-like sliders65are inserted in the through holes via bearing mechanisms. The sliders65are configured to be movable up and down by means of a non-illustrated cam mechanism. A pocket portion forming mold66is fixed on the sliders65. The pocket portion forming mold66is provided with a plurality of plugs66athat is configured to be inserted through the insertion holes64and that are extended in a vertical direction to serve as rod-like pressing elements. The plug66ahas a free end formed in a shape corresponding to an inner face of the pocket portion2. The pocket portion forming mold66moves up and down with the sliders65that are moved up and down by driving the cam mechanism. The lower mold61and the pocket portion forming mold66may be replaceable according to the type of the PTP sheet1that is to be produced.

A circulation path67is formed inside of the sliders65and the pocket portion forming mold66, such that cooling water (or warm water) is circulated through. This configuration suppresses a variation in surface temperature at the respective plugs66a.

The plugs66aare placed at an initial position, at an intermediate stop position and at a protrusion position in this order in a process of forming the pocket portions2and is eventually returned to the initial position. The initial position is a position where the plugs66aare placed at a start of the process of forming the pocket portions2. The plugs66aplaced at this position are located below the insertion holes64and outside of the insertion holes64. The intermediate stop position is a position where the plugs66aare placed in an intermediate stage of the process of forming the pocket portions2. The plugs66aplaced at this position are located in the insertion holes64such as to be arranged away from the container film3across a predetermined interval. The protrusion position is a position where the plugs66aare placed in a last stage of the process of forming the pocket portions2. The plugs66aplaced at this position have end surfaces that are protruded from the lower mold61by a distance corresponding to the depth of the pocket portions2. At least the intermediate stop position among these positions is set by a control device81described later, and the operations of the plugs66aare controlled by the control device81.

The upper plate71is, on the other hand, fixed to a vertically movable upper plate73via a plate72and is configured to be movable along a direction of coming closer to or going away from the lower mold61. The upper mold71has gas supply holes74provided as the first holes at positions opposed to the insertion holes64of the lower mold61. A gas supply path75is formed inside of the plate72and the upper plate73to communicate with the gas supply holes74. A predetermined high-pressure gas (an inert gas, the air according to one or more embodiments) is supplied to the gas supply path75by a gas supply device76configured by, for example, a compressor. According to one or more embodiments, the gas supply device76serves as the expanding unit.

The following describes the formation state detecting device21. The formation state detecting device21includes an illumination device50serving as the illumination unit, a camera51serving as the imaging unit, and a side portion state detector52serving as the side portion state detecting unit as shown inFIGS. 4 to 6.

The illumination device50is configured to irradiate at least the respective pocket portions2of the container film3with a predetermined electromagnetic radiation emitted from a protrusion side of the pocket portions2. The illumination device50includes an electromagnetic radiation device50aand a diffuser plate50bprovided to cover the electromagnetic radiation device50a, and is configured to enable plane emission. The illumination device50according to one or more embodiments irradiates the container film3with an electromagnetic radiation including ultraviolet light.

The camera51has a sensitivity in a wavelength range of the electromagnetic radiation emitted from the illumination device50. The camera51is placed on an opening side of the pocket portions2of the container film3and is configured such that an optical axis OL of a lens of the camera51is perpendicular to the non-forming portion3bof the container film3. A bandpass filter51ais placed corresponding to the lens of the camera51. The bandpass filter51ais provided such as to enable only the ultraviolet light to enter the lens, for example, only the electromagnetic radiation having the wavelength of 253±20 nm to enter the lens. Providing the bandpass filter51acauses only the ultraviolet light transmitted through the container film3out of the electromagnetic radiation emitted from the illumination device50to be subjected to two-dimensional imaging by the camera51. A modification may omit the bandpass filter51aby configuring the electromagnetic radiation device50ato emit only the ultraviolet light.

Transmitted image data obtained by the camera51is luminance image data having different luminance values at respective positions on the basis of a difference in transmittance of the ultraviolet light. A transmitted image based on this data indicates the presence of the plurality of pocket portions2formed by one single operation of the pocket portion forming device16. In other words, the camera51simultaneously takes an image of the plurality of pocket portions2formed by one single operation of the pocket portion forming device16. The transmitted image data thus obtained is input into the side portion state detector52.

The side portion state detector52is configured by a computer system including, for example, a CPU that serves as the arithmetic unit, a ROM that stores various programs, and a RAM that temporarily stores various data, for example, arithmetic data and input and output data. The side portion state detector52includes an image memory53, a calculation results storage device54, a determination memory55, an image and determination conditions storage device56, a camera timing control device57and a CPU and input/output interfaces58.

The image memory53is configured to store image data, such as transmitted image data taken by the camera51. The state with regard to the thickness of the side portion2bis detected, based on the transmitted image data stored in this image memory53. Masking image data obtained by a masking process of the transmitted image data is also stored in the image memory53. The image data may be subjected to a process such as shading correction. The shading correction is performed to correct a variation in lightness of the light caused by a difference in position.

The calculation results storage device54is configured to store the transmittances of the ultraviolet light at respective positions of the bottom portion2aincluded in the transmitted image data, the thicknesses at the respective positions of the bottom portion2aobtained from the transmittances, the average thickness of the bottom portion2a, and statistical data obtained by a stochastic process of these data with regard to the thickness. According to one or more embodiments, the average thickness of the bottom portion2aindicates the state with regard to the thickness of the bottom portion2aand also indicates the state with regard to the thickness of the side portion2b.

The determination memory55is configured to store various information used for detection of the state with regard to the thickness of the pocket portion2. The information stored in the determination memory55includes, for example, the dimensions of the pocket portion2, the shape and the dimensions of a window frame that is used to define an area of the bottom portion2a, a table showing a relationship between the luminance and the transmittance, and a table showing a relationship between the transmittance and the thickness.

The image and determination conditions storage device56is configured by, for example, a hard disk device. The image and determination conditions storage device56is configured to store, for example, the date and the time of state detection and determination conditions used for the state detection.

The camera timing control device57is configured to control the imaging timing of the camera51. This imaging timing is controlled on the basis of a signal from a non-illustrated encoder provided in the PTP packaging machine11. The camera51is controlled to take an image every time the container film3is fed by a predetermined amount.

The CPU and input/output interfaces58is configured to perform various controls in the side portion state detector52. The CPU and input/output interface58executes various processing programs for detection of the state with regard to the thickness of the side portion2bwith using the storage contents of the determination memory55and the like. The CPU and input/output interfaces58is also configured to send and receive signals to and from the control device81described later.

When transmitted image data is input from the camera51, the side portion state detector52having the configuration described above stores the transmitted image data into the image memory53and performs various processes. The various processes include, for example, a masking process of the stored transmitted image data, a process of calculating the transmittances with regard to masking image data obtained by the masking process, a process of calculating the thicknesses at the respective positions of the bottom portion2aand the average thickness of the bottom portion2abased on the transmittances, and a process of storing the calculated average thickness as indication of the state with regard to the thickness of the side portion2b.

More specifically, the masking process is performed to process the transmitted image data by using a window frame for defining the area of the bottom portion2astored in the determination memory55and generate masking image data by extraction of the area corresponding to the bottom portion2afrom the transmitted image data. The masking image data is stored into the image memory53.

The process of calculating the transmittances is performed to detect the luminance values in respective pixels of the area corresponding to the bottom portion2afrom the masking image data and calculate the transmittances at the respective positions of the bottom portion2aby using the detected luminance values and the table that shows the relationship between the luminance and the transmittance and that is stored in the determination memory55. The calculated transmittances are stored into the calculation results storage device54.

The process of calculating the thicknesses calculates the thicknesses at the respective positions of the bottom portion2aby using the calculated transmittances at the respective positions of the bottom portion2aand the table that shows the relationship between the transmittance and the thickness and that is stored in the determination memory55. The process also calculates the average thickness of the bottom portion2aby using the calculated thicknesses at the respective positions of the bottom portion2a. This average thickness of the bottom portion2ais not an average thickness of the bottom portion2awith regard to one pocket portion2but is an average thickness of the respective bottom portions2awith regard to a plurality of pocket portions2simultaneously formed by the pocket portion forming device16. The calculated thicknesses at the respective positions of the bottom portion2aare stored into the calculation results storage device54. The process may calculate an average thickness of the bottom portion2awith regard to a predetermined pocket portion2selected out of the plurality of pocket portions2. The average thickness may be replaced with another thickness-related factor, for example, an intermediate value or a maximum value of the thickness.

The process of storing the state with regard to the thickness stores the calculated average thickness of the bottom portion2aas indication of the state with regard to the thickness of the side portion2binto the calculation results storage device54. In other words, according to one or more embodiments, the state with regard to the thickness of the side portion2bis detected, based on the state with regard to the thickness of the bottom portion2a. The state with regard to the thickness of the side portion2bis not defined from the thickness or the transmittance of the side portion2bitself but is indirectly defined from the information with regard to the thickness of the bottom portion2ain relation to the thickness of the side portion2b.

The side portion state detector52outputs the information with regard to the calculated average thickness of the bottom portion2ato the control device81serving as the controller and to the filling control device82serving as the filling controller. The following describes the control device81and the filling control device82.

The control device81is configured by a computer system including a CPU, a RAM and the like, similarly to the side portion state detector52. The control device81has a function of sending various information including the image data stored in the side portion state detector52to a predetermined display unit (not shown), such as a display. This function enables the information stored in the side portion state detector52to be displayed on the display unit.

The control device81sets the intermediate stop position of the plugs66aand stores the set information with regard to the intermediate stop position. Additionally, the control device81stores information with regard to the initial position of the plugs66aand information with regard to the protrusion position of the plugs66a. The information with regard to the initial position and the information with regard to the protrusion position may be changed according to the depth of the pocket portions2in the PTP sheet1that is to be manufactured.

According to one or more embodiments, the control device81sets the intermediate stop position by a method described below. When the information with regard to the average thickness of the bottom portion2ais input from the side portion state detector52, the control device81calculates a thickness difference by subtracting a thickness reference value stored in advance from the input average thickness. The thickness reference value indicates an ideal average thickness of the bottom portion2aof the pocket portion2. After calculation of the thickness difference, the control device81obtains a position adjustment amount of the plugs66aby using the calculated thickness difference and an adjustment amount calculation table stored in advance, and sets a new intermediate stop position, based on this position adjustment amount. The adjustment amount calculation table is a table showing a relationship between the thickness difference and the position adjustment amount of the plugs66afor cancelling the thickness difference. This table provides a negative value of the position adjustment amount against a positive thickness difference and provides a positive value of the position adjustment amount against a negative thickness difference. The larger thickness difference gives the larger absolute value of the position adjustment amount. The thickness difference of 0 gives the position adjustment amount of 0.

For example, in the case of a positive thickness difference, i.e., in the case where the average thickness of the bottom portion2aof the pocket portion2is larger than the thickness reference value, the control device81obtains a negative value of the position adjustment amount, based on the adjustment amount calculation table. The control device81then sets a position lower than the current intermediate stop position by the absolute value of this position adjustment amount, as a new intermediate stop position.

For example, in the case of a negative thickness difference, i.e., in the case where the average thickness of the bottom portion2ais smaller than the thickness reference value, on the other hand, the control device81obtains a positive value of the position adjustment amount, based on the adjustment amount calculation table. The control device81then sets a position upper than the current intermediate stop position by the absolute value of this position adjustment amount, as a new intermediate stop position.

When the newly set intermediate stop position is higher than a predetermined upper limit position that is set in advance or is lower than a predetermined lower limit position that is set in advance, the control device81determines that the newly set intermediate stop position is inappropriate and performs a predetermined abnormality responding process. The abnormality responding process may be, for example, a process of informing an abnormality or a process of urgently stopping the operation of the PTP packaging machine11.

The following describes a forming process of the pocket portions2performed by control of the control device81with reference toFIG. 8. The forming process of the pocket portions2first performs an intermediate stop position placing process S1. The intermediate stop position placing process S1moves the sliders65to move the pocket portion forming mold66upward and thereby move up the plugs66alocated at the initial position (as shown inFIG. 9). When the plugs66areach the set intermediate stop position, the intermediate stop position placing process S1stops the move of the sliders65and causes the plugs66ato be located at the intermediate stop position. In this state, the end surfaces of the plugs66aare located away from the container film3by a predetermined distance. This predetermined distance is generally smaller than the depth of the pocket portions2.

Subsequently, a clamping process S2moves the upper mold71downward, such that the container film3is sandwiched between the lower mold61in the stationary state and the upper mold71(as shown inFIG. 10). In this state, ring-shaped areas of the container film3located around predetermined forming regions3athat are target areas where the pocket portions2are respectively to be formed, is sandwiched between the respective molds61and71. The intermediate stop position placing process S1and the clamping process S2may be performed simultaneously, or the clamping process S2may be performed prior to the intermediate stop position placing process S1.

Subsequently, an expanding process S3supplies a gas from the gas supply device76to the gas supply holes74via the gas supply paths75and thereby sprays the predetermined forming regions3aof the pocket portions2in the container film3with the compressed air from the surface side (upper side) of the container film3. According to one or more embodiments, the supply of the gas to the gas supply holes74corresponds to the film expanding process. Supplying the gas causes the predetermined forming regions3ato be expanded in an opposite direction (downward direction) to the protruding direction (upward direction) of the pocket portions2, to be stretched and to be thinned (as shown inFIG. 11). The predetermined forming regions3aare expanded to be supported by the end surfaces of the plugs66a. When the predetermined forming regions3aare expanded by supplying the gas, the expanded predetermined forming regions3have substantially the same thicknesses as a whole.

The stretch amount of the container film3and the thicknesses of the predetermined forming regions3aare changed according to the intermediate stop position of the plugs66a. A relatively high intermediate stop position of the plugs66aprovides a relatively small stretch amount of the container film3and thereby provides the predetermined forming regions3ain a generally thick state. A relatively low intermediate stop position of the plugs66a, on the other hand, provides a relatively large stretch amount of the container film3and thereby provides the predetermined forming regions3ain a generally thin state.

Subsequently, a final forming process S4moves the plugs66aupward to be located at the protrusion position. As a result, the expanding direction of the predetermined forming regions3ais reversed to form the pocket portions2having a predetermined depth (as shown inFIG. 12). In the case of deforming the container film3by pressing, an area of the predetermined forming region3acorresponding to the bottom portion2ais in contact with the plug66ato be cooled down and is thus hardly stretched. Accordingly, when the intermediate stop position is set to the relatively high position to provide the predetermined forming region3ain the generally thick state, the area corresponding to the bottom portion2ais maintained thick in the process of pressing by the plug66a. This results in providing the side portion2bof a relatively thin wall in the formed pocket portion2. When the intermediate stop position is set to the relatively low position to provide the predetermined forming region3ain the generally thin state, on the other hand, the area corresponding to the bottom portion2ais maintained thin in the process of pressing by the plug66a. This results in providing the side portion2bof a relatively thick wall in the formed pocket portion2. Adjusting the wall thickness of the predetermined forming region3aby regulating the intermediate stop position of the plug66ain this manner allows for adjustment of the balance between the thickness of the bottom portion2aand the thickness of the side portion2bin the pocket portion2eventually formed.

After the final forming process S4, the pocket portion forming process places the plugs66aat the initial position, releases clamping of the container film3by the respective molds61and71, and is then terminated.

The following describes the filling control device82. The filling control device82serves to change over between permission and prohibition of filling of the tablet5into the pocket portion2by the tablet filling device22and is configured by a computer system including a CPU, a RAM and the like, similarly to the side portion state detector52. When the information with regard to the average thickness of the bottom portion2ais input from the side portion state detector52, the filling control device82determines whether this average thickness is greater than a quality determination reference value set in advance. When the average thickness is equal to or less than the quality determination reference value, i.e., when the bottom portion2ais expected to be sufficiently thin and the side portion2bis expected to have a sufficient thickness, the filling control device82controls the tablet filling device22to fill the tablet5into each of the pocket portions2having this average thickness. When the average thickness is greater than the quality determination reference value, i.e., when the bottom portion2ais expected to be excessively thick and the side portion2bis expected to have an insufficient thickness, on the other hand, the filling control device82controls the tablet filling device22not to fill the tablet5into each of the pocket portion2having this average thickness.

When the side portion2bis expected to have an insufficient thickness, the filing control device82sends a defective signal to the defective sheet discharge mechanism40. As a result, the PTP sheet1related to the defective signal (defective sheet) is discharged by the defective sheet discharge mechanism40. According to a modification, the control device81may be configured to have the functions of the filling control device82and may thus be integrated with the filling control device82.

As described above in detail, even when the balance between the thickness of the bottom portions2aand the thickness of the side portions2bis unintentionally destroyed in the course of production of the PTP sheet1, the configuration of one or more embodiments automatically corrects the destroyed balance and thereby effectively prevents excessive wall thinning of the side portions2b. As a result, this configuration enables the pocket portions2having good gas barrier property to be formed more reliably for a longer time period.

Furthermore, according to one or more embodiments, the side portion state detector52detects the state with regard to the thickness of the side portion2b, based on the state with regard to the thickness of the bottom portion2ain the transmitted image data, by taking advantage of such a correlation between the thickness of the bottom portion2aand the thickness of the side portion2bthat the thick bottom portion2aprovides the thin side portion2band the thin bottom portion2aprovides the thick side portion2b. This configuration enables information required for thickness control of the pocket portions2to be obtained in the shorter time period and sufficiently responds to the high-speed production of the PTP sheet1.

Moreover, the bottom portion2ais arranged to be substantially parallel to the non-forming region3bof the container film3. It is thus likely to cause a difference in transmission of the electromagnetic radiation in the area of the obtained transmitted image data corresponding to the bottom portion2a. This configuration accordingly enables the state with regard to the thickness of the bottom portion2ato be more accurately recognized and thereby enables the state with regard to the thickness of the side portion2bto be more accurately detected. As a result, this configuration ensures the more accurate thickness control of the pocket portions2.

Additionally, the ultraviolet light has the lower transmittance and is more unlikely to transmit through the transparent container film3, compared with the visible light. The configuration of one or more embodiments thus enables the state with regard to the thickness of the bottom portion2aand the state with regard to the thickness of the side portion2bto be more accurately detected, based on the transmitted image data. Accordingly, this configuration may ensure the thickness control of the pocket portions2.

Changing the intermediate stop position of the plugs66aallows for adjustment of the balance between the thickness of the bottom portion2aand the thickness of the side portion2b. Accordingly, the configuration of one or more embodiments enables the balance adjustment of the thickness to be performed extremely easily.

Additionally, when the side portion2bis extremely thin, the filling control device82controls the tablet filling device22not to fill the tablet5into the pocket portion2. In the case where the PTP sheet1is discarded due to the extreme thinness of the side portions2b, this configuration prevents the tablets5from being discarded together with the PTP sheet1and thereby reduces the waste of the tablets5. This configuration also does not require a troublesome work of, for example, taking the filled tablets5out of the pocket portions2for recycle of the tablets5and accordingly enhances the productivity.

The present invention is not limited to the description of the above embodiments but may be implemented, for example, by configurations described below. The present invention may also be naturally implemented by applications and modifications other than those illustrated below.

(a) According to one or more embodiments described above, the illumination device50is configured to emit the electromagnetic radiation including the ultraviolet light. The wavelength of the electromagnetic radiation emitted from the illumination device may be changed according to the material and the color of the container film3. For example, when the container film3is formed from an opaque material made of, for example, aluminum, X rays may be emitted from the illumination device. In another example, when the container film3is formed from a colored translucent material, visible light such as white light may be emitted from the illumination device.

(b) One or more embodiments described above are configured to adjust the balance between the thickness of the bottom portion2aand the thickness of the side portion2b, based on the thickness of the bottom portion2a(average thickness). A modification may be configured to adjust the balance of the thicknesses, based on the transmittance of the electromagnetic radiation in the bottom portion2a.

One or more embodiments described above are also configured to detect the state with regard to the thickness of the side portion2b, based on the state with regard to the thickness of the bottom portion2a. In other words, one or more embodiments are configured to detect the state with regard to the thickness of the side portion2bindirectly from the state with regard to the thickness of the bottom portion2a. A modification may be configured to directly detect the state with regard to the thickness of the side portion2bby obtaining the thickness of the side portion2bor the transmittance of the electromagnetic radiation in the side portion2b. In the modified configuration of directly detecting the thickness of the side portion2bor the like, a camera may be provided for each pocket portion2or for each area including a few pocket portions2, with a view to detecting the thickness along the whole circumference of the side portion2bor the like with the high accuracy.

(c) One or more embodiments described above are configured to adjust the wall thickness of the predetermined forming regions3aand thereby the wall thickness of the pocket portions2by regulating the intermediate stop position of the plugs66a. A modification may be configured to adjust the wall thickness of the predetermined forming regions3aand thereby the wall thickness of the pocket portions2by placing the plugs66aat the initial position to ensure a sufficient distance between the plugs66aand the container film3and then regulating the amount of the gas supplied from the gas supply device76or the like.

(d) When the container film3is formed from an opaque material made of, for example, aluminum, the pocket portion forming device used may be a pocket portion forming device (described in JP 2002-160289A) provided with first plugs configured to preliminarily press and stretch the container film3and second plugs configured to further press the regions of the container film3preliminarily stretched by the first plugs to eventually form the pocket portions2.

In this pocket portion forming device, setting a large pressing amount (stroke amount) of the container film3by the first plugs forms the pocket portions2having relatively thin bottom portions2aand relatively thick side portions2b. Setting a small pressing amount (stroke amount) of the container film3by the first plugs, on the other hand, forms the pocket portions having relatively thick bottom portions2aand relatively thin side portions2b. Accordingly, the balance between the thickness of the bottom portion2aand the thickness of the side portion2bmay be adjusted by regulating the pressing amount by the first plugs.

(e) According to one or more embodiments described above, the illumination device50and the camera51are placed upstream of the tablet filling device22. According to a modification, however, as shown inFIG. 13, the illumination device50and the camera51may be placed downstream of the tablet filling device22. A tablet quality determination device83serving as the content quality determination unit may also be provided to determine the quality of the tablets5, based on the transmitted image data obtained by the camera51. The tablet quality determination device83comprises a processor, and may be configured, for example, to extract regions corresponding to the tablets5from the transmitted image data and make an inspection for the presence or the absence of the tablets5, any breaking or cracking of the tablets5, and the suitability of the shape and the size of the tablets5for the product type, based on the size and the number of the extracted regions. In this modification, the side portion state detector52may detect the average thickness of the bottom portion2aor the like based on a region of the bottom portion2athat does not overlap with the tablet5and may detect the thickness of the side portion2band the transmittance of the electromagnetic radiation in the side portion2b.

This modified configuration may not just detect the state with regard to the thickness of the side portion2bbut determine the quality of the tablets5, based on the transmitted image data obtained by the camera51. This modified configuration accordingly simplifies the PTP packaging machine11and thereby reduces an increase in manufacturing and other costs of the PTP packaging machine11.

(f) According to one or more embodiments described above, the predetermined forming regions3aare expanded by supplying the gas into the gas supply holes74. According to a modification, however, as shown inFIG. 14, a negative pressure supply device68serving as the expanding unit comprised of, for example, a vacuum pump may be provided to supply a negative pressure to the insertion holes64and suck the predetermined forming regions3aso as to expand the predetermined forming regions3a. In this modification, supplying the negative pressure to the insertion holes64corresponds to the film expanding process. In the configuration of expanding the predetermined forming regions3aby suction, the predetermined forming regions3ahave substantially the same thicknesses as a whole, as in the configuration of expanding the predetermined forming regions3aby supplying the gas. Another modification may expand the predetermined forming regions3aby simultaneously performing the supply of the gas to the gas supply holes74and the supply of the negative pressure to the insertion holes64.

(g) The embodiments described above are configured to eventually form the pocket portions2by reversing the expanding direction of the predetermined forming regions3a. A modification may, however, be configured to form the pocket portions2without reversing the expanding direction of the predetermined forming regions3a. For example, as shown inFIG. 15andFIG. 16, the modified configuration may form the pocket portions2by using preliminary stretch plugs69to press and stretch the predetermined forming regions3aand then causing the predetermined forming regions3ato be expanded in a direction opposite to the preliminary stretch plugs69and come into close contact with a mold77having a shape corresponding to the pocket portions2by supply of a negative pressure (by vacuum drawing).

In this modified configuration, setting a relatively large pressing amount by the preliminary stretch plug69provides a relatively thick area of the predetermined forming region3acorresponding to the bottom portion2aand a relatively thin area of the predetermined forming region3acorresponding to the side portion2b. Setting a relatively small pressing amount by the preliminary stretch plug69, on the other hand, provides a relatively thin area of the predetermined forming region3acorresponding to the bottom portion2aand a relatively thick area of the predetermined forming region3acorresponding to the side portion2b. In any case, the area corresponding to the bottom portion2ais made thicker than the area corresponding to the side portion2b. When the predetermined forming region3ais expanded by supply of the negative pressure, the area corresponding to the bottom portion2aand the area corresponding to the side portion2bare stretched almost evenly. Accordingly, the balance between the thickness of the bottom portion2aand the thickness of the side portion2ain the pocket portions2may be adjusted by changing the pressing amount by the preliminary stretch plugs69. The predetermined forming regions3amay be expanded by the supply of the gas (i.e., the pressure).

In the expanding process S3, the pocket portions2may be formed by causing the predetermined forming regions3ato be expanded in a direction opposite to that of the above embodiments (i.e., in a direction opposite to the plugs66a) by the supply of the gas or the supply of the negative pressure (i.e., the pressure or vacuum drawing) and subsequently pressing inside of the expanded predetermined forming regions3aby means of the plugs66a. In this modification, receiving elements may be provided on the opposite side to the plugs66aacross the container film3to support the expanded predetermined forming regions3a. The position of the receiving elements may be regulated to regulate the stretch amount of the predetermined forming regions3aand accordingly to adjust the wall thickness of the predetermined forming regions3aand thereby the wall thickness of the pocket portions2. The receiving elements may be retracted to a position that does not interfere with the move of the plugs66ain the process of pressing the predetermined forming regions3aby means of the plugs66a.

The technique of adjusting the balance between the thickness of the bottom portion2aand the thickness of the side portion2bis not limited to the techniques described above, but any other techniques may be employed for the balance adjustment.

(h) The embodiments described above are configured to regulate the intermediate stop position of the plugs66a, based on the difference (thickness difference) between the average thickness of the bottom portion2aand the thickness reference value. In other words, the above embodiments are configured to regulate the intermediate stop position of the plugs66aunless the average thickness is equal to the thickness reference value. A modification may, however, be configured to regulate the intermediate stop position of the plugs66a, for example, only when the average thickness of the bottom portion2ais larger than a predetermined upper limit value or is smaller than a predetermined lower limit value. In other words, the modification may be configured not to change the intermediate stop position of the plugs66awhen the average thickness of the bottom portion2ais equal to or larger than the above lower limit value and is equal to or smaller than the above upper limit value. This modified configuration reduces the processing load involved in regulation of the intermediate stop position and accordingly reduces the manufacturing and other costs of the PTP packaging machine11.

The above upper limit value and the above lower limit value may be reference values for determining the quality of the pocket portions2with regard to the gas barrier property or may be values set with adding some margins to these reference values (i.e., values having smaller absolute values than these reference values). In the latter case, the balance between the thickness of the bottom portion2aand the thickness of the side portion2bmay be corrected before the gas barrier property of the pocket portion2becomes actually insufficient. This configuration more reliably prevents the defective PTP sheet1having poor gas barrier property from being manufactured, thus reducing the costs relating to production and enhancing the productivity.

(i) The above embodiments describe the PTP sheet1as the blister sheet. The technical scope of the present invention may, however, be applied to any blister sheet other than the PTP sheet1. The above embodiments describe the tablet5as the content. The content is, however, specifically limited but may be a capsule or an electronic component. Furthermore, the materials of forming the container film3and the cover film4may be changed.

REFERENCE SIGNS LIST