Laminate as authentication medium, fixed sheet stack for laminate, and method and device for producing fixed sheet stack

Abstract

A manufacturing method according to an embodiment comprises: causing the positions of a mount sheet and a lamination sheet to face each other to form a facing sheet stack; and locally heating and welding at least two anchor spots on the facing sheet stack while causing the sheets to face each other. Each of the sheets is a thermosensitive recording body or a plastic sheet. Alternatively, a laminate according to an embodiment is obtained by laminating a plastic sheet and a thermosensitive recording body having welding marks at corners. According to the present invention, it is possible to provide a method and a device for producing a fixed sheet stack in which a heat-sensitive recording body is fixed at an accurate position without impairing the color developability of the heat-sensitive recording body. Also provided are the produced fixed sheet stack and a laminate as an authentication medium produced from the fixed sheet stack.

Description

Laminate as an authentication medium, immobilized sheet stack for laminate, method for manufacturing an immobilized sheet stack, and manufacturing apparatus.

[0001] Embodiments of the present invention relate to a fixed sheet stack in which a plastic sheet and a thermal recording body are stacked, a laminate as an authentication medium, a fixed sheet stack for a laminate, a method for manufacturing a fixed sheet stack, and a manufacturing apparatus.

[0002] Preventing forgery and alteration of authentication materials such as passports and ID cards is crucial. In particular, altered passports in which the facial photograph has been replaced with that of another person are easy to manufacture and difficult to distinguish from genuine items because the rest of the card is authentic. Therefore, deterring such alterations is a major challenge.

[0003] In contrast, a method that records owner information by carbonizing the inside of a polycarbonate substrate (hereinafter also referred to as "plastic sheet") using the energy of laser irradiation makes it difficult to erase the recorded information later, thus effectively deterring tampering.

[0004] However, when recording information using laser carbonization, the owner's facial image will be a monochrome image. On the other hand, color images can convey the features of a person in detail, resulting in higher visibility and improved authentication accuracy.

[0005] To achieve both the anti-tampering effect of laser writing and colorization, a technology is used in which a thermal recording material that reacts with a laser to produce color is incorporated inside a plastic sheet. The thermal recording material has a structure in which multiple thermal recording layers containing leuco dyes and an insulating layer are laminated on a thin plastic sheet, and by irradiating it with a laser of a specific wavelength, CMY is produced to draw a color image.

[0006] International Patent Publication No. 2023-176942 Japanese Patent No. 2991032

[0007] However, the manufacturing of authentication media using thermal recording materials as described above presents several challenges stemming from the physical and thermal properties of the materials.

[0008] Firstly, there is a problem with placement accuracy due to the "warping" of the thermal recording material. Because thermal recording materials are manufactured through a multi-layer coating and drying process, internal stress accumulates, making them prone to significant warping. This warping makes the thermal recording material prone to shifting during lamination.

[0009] Secondly, thermal recording materials are sensitive to heat during sheet processing, and their tolerance for heat is narrow.

[0010] Thus, it is not easy to prevent the thermal recording material from shifting while fixing it in place without damaging the components.

[0011] The present invention has been made in view of these circumstances, and its first objective is to provide a method and apparatus for manufacturing a fixed sheet stack in which a thermal recording material is fixed without impairing the color development properties of the thermal recording material. The second objective is to provide such a fixed sheet stack and a laminate to be used as an authentication medium manufactured from the fixed sheet stack.

[0012] To achieve the above objectives, the present invention employs the following measures.

[0013] A first aspect of the present invention is a laminate comprising a thermal recording body having welding marks on its corners and / or edges, and a plastic sheet.

[0014] A second aspect of the present invention is a laminate of the first aspect, characterized in that the welding marks are marks.

[0015] A third aspect of the present invention is a laminate of the second aspect, characterized in that the mark is one of a coat of arms, a national flag, a symbol, a signature, or a combination thereof.

[0016] A fourth aspect of the present invention is a laminate of the second aspect, characterized in that the mark is identifiable by visual inspection or camera.

[0017] A fifth aspect of the present invention is a laminate of the fourth aspect, characterized by having infrared absorbing ink printed on it.

[0018] A sixth aspect of the present invention is a manufacturing method comprising: an arranging step of making an adhesive sheet and a mount sheet face each other to form a facing sheet stack; and a welding sequence of welding anchor spots on the facing sheet stack, wherein there are at least two anchor spots on the facing sheet stack, the adhesive sheet is an individual piece of a heat-sensitive recording material or a plastic sheet, the mount sheet is a plastic sheet, and the welding sequence comprises a heating step of locally heating the anchor spots in a state where the mount sheet and the adhesive sheet are in direct contact, or in a state where the mount sheet is in contact with one surface of an intermediate layer and the adhesive sheet is in contact with the other surface of the intermediate layer.

[0019] A seventh aspect of the present invention is the manufacturing method according to the sixth aspect, wherein the heat-sensitive recording material has a thermoplastic resin layer on an outermost surface, and any one layer in the heat-sensitive recording material has heat insulating properties.

[0020] An eighth aspect of the present invention is the manufacturing method according to the seventh aspect, wherein the thermoplastic resin layer has heat insulating properties.

[0021] A ninth aspect of the present invention is the manufacturing method according to the sixth aspect, further comprising repeating the welding sequence until all anchor spots on the facing sheet stack are welded.

[0022] A tenth aspect of the present invention is the manufacturing method according to the sixth aspect, wherein the heating step includes heating by a heater chip.

[0023] An eleventh aspect of the present invention is the manufacturing method according to the tenth aspect, wherein a contact surface of the heater chip has a curvature when viewed from a direction orthogonal to the thickness direction of the mount sheet.

[0024] A twelfth aspect of the present invention is the manufacturing method according to the seventh aspect, wherein the heating step comprises irradiating the anchor spots with a laser to locally heat the anchor spots.

[0025] A thirteenth aspect of the present invention is the manufacturing method according to the twelfth aspect, wherein the laser is an infrared laser, and the thermoplastic resin layer is infrared-absorbing.

[0026] A fourteenth aspect of the present invention is the manufacturing method according to the twelfth aspect, characterized in that the laser is an infrared laser, and the plastic sheet has printing of infrared absorbing ink.

[0027] A fifteenth aspect of the present invention is a manufacturing method comprising: an arranging step of facing an adhesive sheet and a mount sheet to form a facing sheet stack; a positioning step of arranging a heater chip at an anchor spot on the facing sheet stack; after the positioning step, a pressing step of pressing the mount sheet toward the adhesive sheet side by the heater chip; a heating step of, while maintaining the pressed state, starting heating of the heater chip, raising the temperature of the heater chip to a predetermined welding temperature, and after the temperature of the heater chip reaches the welding temperature, maintaining the temperature of the heater chip at the welding temperature for a predetermined heating holding time or longer; and a cooling step of cooling the heater chip while maintaining the pressed state after the heating step, wherein after a predetermined cooling time elapses, pressing of the mount sheet by the heater chip is released to end the pressing step, when there are unwelded anchor spots on the facing sheet stack, repeating the steps from the positioning step to the heating step, and when there are no unwelded anchor spots on the facing sheet stack and the number of welded sheets is a predetermined number, the process is ended, otherwise, the mount sheet and the adhesive sheet fixed in the steps from the arranging step to the heating step are used as a new adhesive sheet, a new mount sheet to be welded to the new adhesive sheet is prepared, the new adhesive sheet and the new mount sheet are faced to each other to form a facing sheet stack, and layering is performed by repeating the steps from the arranging step to the repeating step, thereby manufacturing a fixed sheet stack in which a predetermined number of sheets are welded, wherein the anchor spots on the fixed sheet stack are at least two locations.

[0028] A sixteenth aspect of the present invention is the manufacturing method according to the fifteenth aspect, characterized in that the adhesive sheet is a piece of thermosensitive recording medium or a plastic sheet, and the mount sheet is a plastic sheet.

[0029] A seventeenth aspect of the present invention is a manufacturing method according to the sixteenth aspect, characterized in that the adhesive sheet consists of a perforated plastic sheet and individual pieces of thermal recording material placed in the holes.

[0030] An eighteenth aspect of the present invention is a manufacturing method according to the fifteenth aspect, characterized in that when a product area used for a product is cut from a fixed sheet stack, the area that is pressurized is outside the product area.

[0031] A 19th aspect of the present invention is a manufacturing method according to the 15th aspect, characterized in that when a product area to be used for the product is cut along a cutting line from a fixed sheet stack, the anchor spot is on the cutting line.

[0032] A 20th aspect of the present invention is a manufacturing method according to the 16th aspect, characterized in that the individual pieces of the thermal recording body have welding marks.

[0033] A 21st aspect of the present invention is a manufacturing method according to the 20th aspect, characterized in that the contact surface of the heater chip, viewed from a direction perpendicular to the thickness direction of the mounting sheet, has curvature.

[0034] A 22nd aspect of the present invention is a manufacturing method according to the 15th aspect, characterized in that the time required for the temperature of the heater tip to rise to the welding temperature after the start of heating of the heater tip is shorter than the heating and holding time.

[0035] A 23rd aspect of the present invention is a fixed sheet stack comprising a plurality of sheets stacked and welded together, characterized in that each sheet is welded to the sheet facing it, and there are at least two welded anchor spots.

[0036] A 24th aspect of the present invention is a fixed sheet stack according to the 23rd aspect, characterized in that the plurality of sheets include sheets made of plastic sheets and sheets made of thermal recording material.

[0037] A 25th aspect of the present invention is a fixed sheet stack according to the 24th aspect, characterized in that the thermal recording material has welding marks.

[0038] A 26th aspect of the present invention is a manufacturing apparatus for producing a fixed sheet stack, comprising: a stage on which a mount sheet is placed; a pick-and-place machine that descends from above the stage, aligns and places an adhesive sheet on the mount sheet, and holds it therein; and a local heating head provided below the stage for welding the mount sheet to the adhesive sheet, wherein the stage is made of glass, or the stage has holes or windows for welding the mount sheet to the adhesive sheet, and the local heating head locally heats the mount sheet from below the stage while the adhesive sheet is held on the mount sheet by the pick-and-place machine, with the mount sheet and adhesive sheet sandwiched together, thereby welding the mount sheet to the adhesive sheet and producing a fixed sheet stack.

[0039] A 27th aspect of the present invention is a manufacturing apparatus of the 26th aspect, further comprising a robotic arm for transporting a pick-and-place machine to a position where it begins to descend.

[0040] A 28th aspect of the present invention is a manufacturing apparatus according to the 26th or 27th aspect, wherein the pick-and-place machine is equipped on its bottom surface with an adsorption section for adsorbing adhesive sheets and a pressure receiving section that receives pressure from a local heating head during local heating.

[0041] A 29th aspect of the present invention is a manufacturing apparatus according to the 26th aspect, characterized in that a positioning pin is provided on the stage for positioning the mounting sheet.

[0042] A 30th aspect of the present invention is a manufacturing apparatus according to the 26th aspect, characterized in that the local heating head constitutes a pulse heat unit comprising a pulse heat power supply and a local heating head heated by the pulse heat power supply, and while the adhesive sheet is held on the mounting sheet by a pick-and-place machine, the local heating head presses the mounting sheet from below the stage through a hole, and heats the mounting sheet while the mounting sheet and the adhesive sheet are sandwiched together with the pick-and-place machine.

[0043] A 31st aspect of the present invention is a manufacturing apparatus according to the 30th aspect, characterized in that the pulse heat unit is equipped with a plurality of local heating heads, the number of holes provided in the stage corresponds to the number of local heating heads, and when heating the mounting sheet, each of the plurality of local heating heads heats the mounting sheet by passing through one of the holes, thereby heating multiple locations simultaneously.

[0044] A 32nd aspect of the present invention is a manufacturing apparatus comprising a stage on which mounting sheets are arranged, a pick-and-place machine provided below the stage for holding adhesive sheets, and a local heating head provided above the stage for welding the mounting sheets to the adhesive sheets, wherein the stage is provided with a through-hole through which the pick-and-place machine holding the adhesive sheets can pass, the pick-and-place machine rises from below the stage through the through-hole to bring the held adhesive sheet and the mounting sheet facing each other, and the local heating head locally heats the mounting sheet while the adhesive sheet is facing the mounting sheet by the pick-and-place machine, welding the mounting sheet to the adhesive sheet to produce a fixed sheet stack.

[0045] A 33rd aspect of the present invention is a manufacturing apparatus according to the 32nd aspect, further comprising a robotic arm for transporting a pick-and-place machine to a position where it begins to rise.

[0046] A 34th aspect of the present invention is a manufacturing apparatus according to the 32nd or 33rd aspect, wherein the pick-and-place machine is equipped on its upper surface with an adsorption section for adsorbing adhesive sheets and a pressure receiving section that receives pressure from a local heating head during local heating.

[0047] A 35th aspect of the present invention is a manufacturing apparatus according to the 32nd aspect, characterized in that a stage is provided with positioning pins for positioning the location where a mount sheet is placed.

[0048] A 36th aspect of the present invention is a manufacturing apparatus according to the 32nd aspect, characterized in that the local heating head is equipped with a heater tip, the heater tip presses the mounting sheet of the opposing sheet stack from above the stage, and the mounting sheet is locally heated while sandwiched together with the pick-and-place machine.

[0049] A 37th aspect of the present invention is a manufacturing apparatus according to the 32nd aspect, characterized in that the local heating head is a laser head, a laser-transmitting plate presses the mounting sheet of the opposing sheet stack from above the stage, and the mounting sheet and the adhesive sheet are sandwiched together with a pick-and-place machine, and the mounting sheet is locally heated by laser irradiation from the laser head.

[0050] A 38th aspect of the present invention is a manufacturing apparatus according to the 29th aspect, characterized in that the stage includes a plurality of regions, each of which a mounting sheet is arranged, and each of the plurality of regions is provided with a positioning pin and a hole.

[0051] A 39th aspect of the present invention is a manufacturing apparatus according to the 29th aspect, characterized in that the mount sheet is a large mount sheet capable of simultaneously manufacturing multiple fixed sheet stacks, and the stage is provided with holes for each region in which multiple fixed sheet stacks are manufactured.

[0052] A forty-th aspect of the present invention is a manufacturing apparatus according to the 38th or 39th aspect, characterized by comprising a number of pick-and-place machines and local heating heads equal to the number of regions.

[0053] A forty-first aspect of the present invention is a manufacturing apparatus according to the third or third aspect, characterized in that it comprises fewer pick-and-place machines and local heating heads than the number of regions, each pick-and-place machine is provided with a robotic arm for transporting it to a position where it begins to descend, and each local heating head is provided with a robotic arm for transporting it to a position where it begins to rise.

[0054] A forty-second aspect of the present invention is a manufacturing apparatus according to the third-fifth aspect, characterized in that the stage includes a plurality of regions, each of which a mounting sheet is arranged, and each of the plurality of regions is provided with a positioning pin and a through-hole.

[0055] A forty-third aspect of the present invention is a mounting sheet that allows for the simultaneous production of multiple fixed sheet stacks, and is characterized in that the stage is provided with through-holes for each region in which the multiple fixed sheet stacks are produced. This is a manufacturing apparatus according to the third-fifth aspect of the present invention.

[0056] A forty-fourth aspect of the present invention is a manufacturing apparatus of the forty-second or forty-third aspect, characterized by comprising a number of pick-and-place machines and local heating heads equal to the number of regions.

[0057] A forty-fifth aspect of the present invention is a manufacturing apparatus according to the forty-second or forty-third aspect, characterized in that it comprises fewer pick-and-place machines and local heating heads than the number of regions, each pick-and-place machine is provided with a robotic arm for transporting it to a position where it begins to rise, and each local heating head is provided with a robotic arm for transporting it to a position where it begins to descend.

[0058] A forty-sixth aspect of the present invention is a method for manufacturing a fixed sheet stack, comprising: a placement step of arranging a mount sheet on a stage; a holding step in which a pick-and-place machine descends from above the stage, aligns and places an adhesive sheet on the mount sheet, and holds it therein; a pressing step in which, during the holding step, a welding machine rises from below the stage and presses the mount sheet through a hole provided in the stage; and a welding step in which the welding machine holds the mount sheet and the adhesive sheet between itself and the pick-and-place machine, and locally heats the mount sheet to weld it to the adhesive sheet.

[0059] A forty-seventh aspect of the present invention is a method for manufacturing a fixed sheet stack, characterized by comprising: a placement step of arranging a mount sheet on a stage; a holding step of a pick-and-place machine rising from below the stage, passing through a through-hole provided in the stage, and holding the attached sheet it is holding facing the mount sheet; and a welding step of locally heating the mount sheet during the holding step to weld it to the attached sheet.

[0060] According to the present invention, a method and apparatus can be provided for manufacturing a fixed sheet stack in which a thermal recording material is fixed in an accurate position without impairing its color development, at low cost and with high production efficiency. Furthermore, it is possible to provide a fixed sheet stack with such excellent quality and a laminate to be used as an authentication medium manufactured from the fixed sheet stack.

[0061] Figure 1 is a diagram showing the relationship between the heater tip and the workpiece in a manufacturing apparatus to which the manufacturing method for a fixed sheet stack according to the first embodiment is applied. Figure 2 is an enlarged side view of the vicinity of the heater tip illustrating the welding mechanism by the heater tip. Figure 3 is a conceptual diagram schematically showing the structure of the color development layer of a thermal recording material. Figure 4A is a block diagram showing an example of the configuration of a manufacturing apparatus to which the manufacturing method for a fixed sheet stack according to the first embodiment is applied. Figure 4B is a sequence diagram showing the operation flow of each part of the manufacturing apparatus shown in Figure 4A. Figure 5 is a temperature profile diagram showing an example of the change in the temperature of the heater tip over time during welding. Figure 6 is a timing diagram showing the time relationship of the heater tip temperature obtained from (a) the heating start signal, (b) the welding temperature, (c) the pulse width, and (d) the thermocouple voltage. Figure 7 is a top view showing an example of a fixed sheet stack. Figure 8 is a diagram illustrating the welding marks realized according to the shape of the tip of the heater tip. Figure 9 is a table summarizing the welding results obtained from experiments. Figure 10 is a table showing the comparison results of the characteristics of various welding methods. Figure 11 shows an example of the relationship between the shape of the tip of the heater chip and the welding marks. Figure 12 shows an example of an immobilized sheet stack manufactured by the manufacturing apparatus shown in Figure 4A according to the process shown in Figure 4B. Figure 13 is a perspective view of a primary immobilized sheet stack showing several patterns of the location of welding marks remaining on the primary immobilized sheet stack. Figure 14 is a perspective view of a secondary immobilized sheet stack showing several patterns of the location of welding marks remaining on the secondary immobilized sheet stack. Figure 15 is a perspective view of a secondary immobilized sheet stack showing the relationship between the cutting lines and the welding marks. Figure 16 is a perspective view of a primary immobilized sheet stack with a cross-shaped cutting line perpendicular to the center point of the primary immobilized sheet stack. Figure 17 is a perspective view showing an example of a primary immobilized sheet stack with the periphery of individual pieces of thermal recording material welded. Figure 18 is a perspective view of a primary immobilized sheet stack with a cross-shaped cutting line perpendicular to the center point of the primary immobilized sheet stack. Figure 19 is a functional block diagram showing an example of the functional configuration of the manufacturing apparatus according to the third embodiment. Figure 20 is a conceptual diagram showing each step of the manufacturing method carried out by the manufacturing apparatus according to the third embodiment.Figure 21 is a perspective view illustrating an example of the stage configuration in the third embodiment. Figure 22 is a perspective view showing an example of the pick-and-place machine configuration in the third embodiment. Figure 23 is a perspective view showing an example of a part of the configuration of the rolls of thermal recording material placed in the pick-and-place machine in the third embodiment. Figure 24 is a conceptual diagram showing each step of a conventional method for manufacturing a fixed sheet stack. Figure 25 is a conceptual diagram showing each step of a manufacturing method carried out by a manufacturing apparatus according to the fourth embodiment. Figure 26 is a diagram showing the pick-and-place process by a pick-and-place machine in the fourth embodiment. Figure 27 is a perspective view showing an example of a part of the configuration of the rolls of thermal recording material placed in the pick-and-place machine in the fourth embodiment. Figure 28 is a perspective view showing an example of a multi-panel stage applied in the manufacturing apparatus of Modification 1. Figure 29 is a schematic configuration diagram of the manufacturing apparatus 1 according to the first embodiment. Figure 30 is a block diagram showing various schematic configuration examples of a welding machine. Figure 31 is a block diagram showing an example of the configuration of an XY positioner.

[0062] Each embodiment of the present invention will be described below with reference to the drawings. The embodiments described below are more specific to any of the above embodiments. The items described below can be incorporated into each of the above embodiments individually or in combination.

[0063] The embodiments described below illustrate examples that embody the technical concept of the present invention, and the technical concept of the present invention is not limited to the materials, shapes, structures, and arrangements of the components described below. Various modifications can be made to the technical concept of the present invention within the technical scope defined by the claims described in the claims.

[0064] In the drawings referenced in the following description, components with similar or identical functions are given the same reference numerals. It should be noted that the drawings are schematic, and the relationships between dimensions in the thickness direction and dimensions perpendicular to the thickness direction (i.e., in-plane direction), as well as the relationships between dimensions in the thickness direction of multiple layers, may differ from reality. Therefore, specific dimensions should be determined by referring to the following description. It should also be noted that the dimensional relationships between two or more components may differ across multiple drawings.

[0065] In this disclosure, "upper surface" and "lower surface" refer to the two main surfaces of the plate-like member or the layer contained therein, namely the surface perpendicular to the thickness direction and having the largest area, and its back surface, which are shown as the upper surface and the lower surface in the drawings, respectively. Furthermore, "end surface" refers to the surface of the plate-like member or the layer contained therein that is located on the outer periphery when viewed from a direction parallel to the thickness direction. The orientation in the drawings of a certain object may or may not coincide with the orientation in the actual usage situation.

[0066] Furthermore, in this disclosure, the phrase "AA on BB" is used independently of the direction of gravity. The state specified by the phrase "AA on BB" includes the state in which AA faces BB. The phrase "AA on BB" does not exclude the presence of one or more other components between AA and BB.

[0067] (First Embodiment) A method for manufacturing a fixed sheet stack according to the first embodiment will be described.

[0068] Figure 1 shows the relationship between the heater chip and the workpiece in a manufacturing apparatus to which the manufacturing method for a fixed sheet stack according to the first embodiment is applied.

[0069] Figure 2 is an enlarged side view of the vicinity of the heater tip, illustrating the welding mechanism by the heater tip.

[0070] In a manufacturing apparatus to which the manufacturing method for a fixed sheet stack according to the first embodiment is applied, as shown in Figure 1, a plastic sheet 50 is positioned in alignment with individual pieces of thermal recording element 70 placed on a stage 10, the thermal recording element 70 and the plastic sheet 50 are facing each other, and a fixed sheet stack (a fixed sheet stack 40 described later) is manufactured by welding the thermal recording element 70 and the plastic sheet 50 together using a welding machine 30 from the side of the plastic sheet 50 opposite to the thermal recording element 70 (upper side in the figure). At this time, the position of the anchor spot on the stage becomes the pressure receiving section 22.

[0071] The welding machine 30 can be a pulse heat unit or a laser welding machine. It may also be an ultrasonic welding machine or an induction heating device. Furthermore, the local heating head 32 applied to anchor spots other than the heat-sensitive recording piece may be a metal heater controlled to maintain a constant temperature. The metal of the metal heater is heated when the heater inside the metal generates heat due to the current supplied from the power supply.

[0072] The welding machine 30 can be classified into two types: one that heats by contact and one that heats without contact. The contact heating type includes heating by heat transfer from a pulse heat unit and heating by friction using an ultrasonic welding machine. The non-contact heating type includes heating by laser using a laser welding machine and heating by electromagnetic induction using an induction heating device.

[0073] The pulsed heat unit includes a power supply 31 and a local heating head 32 as shown in Figure 1. The tip of the local heating head 32 has a heater tip 33. The heater tip 33 is part of the local heating head 32. A thermocouple 34 is attached to the heater tip 33. The laser welding machine emits a laser from the tip of the local heating head using power from the power supply.

[0074] The laser head of a laser welding machine can be a carbon dioxide laser. The laser output can be between 50W and 300W. In induction heating devices, a fluctuating magnetic field is generated from the coil-type local heating head by the alternating current from the power supply. In ultrasonic welding machines, power from an oscillator is used to apply vibrations from a horn to the target sheet. The frictional heat generated by these vibrations can weld the target sheet.

[0075] Next, the thermal recording device 70 will be described.

[0076] Figure 3 is a conceptual diagram illustrating the structure of the color-developing layer of a thermal recording material.

[0077] The thermal recording body 70 can be rectangular in the xy plane in the figure and includes multiple color-developing layers 100 as illustrated in Figure 3. The thermal recording body 70 has a leuco layer 71 laminated on top of a polycarbonate layer 72, which is made by layering multiple thermal recording layers containing leuco dyes and insulating layers. The polycarbonate layer 72 is thermoplastic.

[0078] The color-developing layer 100 contains a photothermal conversion material 102, a color developer 103, and a leuco dye 104. The thermal recording body 70 also has an insulating layer between the color-developing layers 100. The insulating layer has insulating properties. The thermal recording body 70 has a thermoplastic resin layer on the outermost surface.

[0079] The insulation layer may contain a porous filler. An example of a porous filler is porous silica. The thermoplastic resin can be polyester resin, acrylonitrile-butadiene-styrene copolymer resin (ABS), vinyl chloride-vinyl acetate copolymer resin, PET-G, polypropylene, polycarbonate, triacetate, polyamide, etc. Other resins that meet the standards of ISO / IEC 7810 ID-1 or ICAO ID-3 are also applicable. The outermost thermoplastic resin layer may have heat-generating properties.

[0080] This heat generation property can be achieved through infrared absorption. Alternatively, it could be high friction to convert friction caused by ultrasound into heat, or conductivity to induce induction heating.

[0081] The photothermal conversion material 102 absorbs only laser light of a specific wavelength and generates heat. This heat causes the color developer 103 and the leuco dye 104 to react, and the leuco dye 104 develops into a predetermined color. The components and contents of the photothermal conversion material 102, the leuco dye 104, and the color developer 103 are adjusted according to the color to be developed.

[0082] The thermal recording material 70 includes three or more color-emitting layers 100 that emit light in response to lasers of three different wavelengths (for example, red, blue, green, and yellow wavelengths). This allows for the selective emission of each CMY color, and the mixing of these colors to form a full-color facial image. This enables the formation of the owner's facial image by laser irradiation when the item is personalized. This facial image is difficult to tamper with, and because it requires a thermal recording material and a compatible laser printing device, it is difficult to manufacture counterfeit or tamper-proof items. Furthermore, it improves visual recognition, making it easier to detect the unauthorized use of another person's ID or counterfeit products.

[0083] Next, I will explain the plastic sheet 50.

[0084] The material of the plastic sheet 50 can consist of a thermoplastic polymer, essentially only a thermoplastic polymer, or essentially a thermoplastic polymer with inorganic or organic fillers. This facilitates welding. The plastic sheet 50 can be homogeneous or composite. In the case of a composite, it can be a multilayer of homogeneous polymers. Alternatively, the composite may consist of a continuous phase and a discrete phase.

[0085] Inorganic fillers can be metal compounds. Specific examples of metal compounds include titanium dioxide, barium sulfate, and calcium carbonate. Thermoplastic polymers can be monopolymers or copolymers only. Alternatively, thermoplastic polymers may essentially consist of monopolymers, copolymers, or both.

[0086] Specific examples of monopolymerization include polycarbonate (PC), polyester, polyolefin, and PA (polyamide). Alternatively, copolymerization can be the copolymerization of these polymers. Other specific examples of copolymerization include ABS (acrylonitrile-butadiene-styrene) and PVC (polyvinyl chloride). Polyolefins include polyethylene (PE) and polypropylene (PP). A specific example of polyester is PET (polyethylene terephthalate).

[0087] A specific example of polyamide (PA) is nylon. Biodegradable plastics, biomass plastics, and recycled plastics can also be used.

[0088] Furthermore, thermoplastic polymers that meet the standards of ISO / IEC 7810 ID-1 or ICAO ID-3 are preferred.

[0089] The mounting sheet transfers heat from the heater chip or metal heater to the adhesive sheet. In other words, the mounting sheet has heat conductivity.

[0090] If the welding machine 30 is a laser welding machine, the mounting sheet is preferably one that transmits a portion of the laser. In this case, the mounting sheet is laser-transparent. The mounting sheet may also absorb a portion of the laser and convert it into heat. If the welding machine 30 consists of an ultrasonic heating device, the ultrasonic waves transmitted from the horn to the mounting sheet are propagated to the adhesive sheet. The specific configurations in these cases will be explained in Modification 3, which will be described later.

[0091] The thickness of the plastic sheet 50 can be between 30 μm and 75 μm. The outer shape of the plastic sheet 50 can be rectangular, with the shorter side being between 30 cm and 60 cm, and the longer side being between 50 cm and 100 cm. The plastic sheet can be cut from the roll to the specified size by slitting or cutting.

[0092] Next, we will explain how to weld the plastic sheet 50 to the thermal recording body 70 using the welding machine 30.

[0093] Figure 4A is a block diagram showing an example of the configuration of a manufacturing apparatus to which the manufacturing method for a fixed sheet stack according to the first embodiment is applied.

[0094] Figure 4B is a sequence diagram showing the processing flow using the manufacturing equipment shown in Figure 4A.

[0095] The manufacturing apparatus 1 comprises a control device 2, a robot arm 5 with an operator display 5a, and a stage 10. The control device 2 comprises a welding machine 30, a welding controller 3, and an XY positioner 4. The welding controller 3 can be implemented as a PLC (Programmable Logic Controller), an industrial PC, a PAC (Process Automation Controller), or a DCS (Distributed Control System).

[0096] The stage can be moved using the XY positioner 4. The local heating head may also be moved to an anchor spot using the XY positioner 4. This XY positioner 4 can be a gantry-type XY stage or a SCARA robot.

[0097] The pulse heat unit comprises a power supply 31, a local heating head 32, and an actuator 35. The local heating head 32 includes a heater tip 33. The heater tip 33 includes a thermocouple 34. The laser welding machine comprises a power supply 31 and a local heating head 32. It may also include an actuator 35. The local heating head 32 of the laser welding machine is a laser head.

[0098] When manufacturing a fixed sheet stack using the manufacturing apparatus 1 shown in Figure 4A, the operator first inputs the coordinates of the anchor spots on the mounted sheet, the heating conditions at each welding spot, etc., to the operator display 5a on the robot arm 5.

[0099] Based on the input, the operator display 5a operates the robot arm 51 to position the adhesive sheets, which are individual pieces of the thermal recording body 70, on the stage 10, aligning them with the mounting sheet, so that the adhesive sheets and the mounting sheet face each other. Once the robot arm 5 completes this positioning, the operator display 5a outputs work completion information n, including processing conditions, to the welding controller 3 (positioning step).

[0100] When the welding controller 3 receives work completion information n, it outputs a positioning signal e to the XY positioner 4 so that the local heating head 32 is positioned at the anchor spot, based on the processing conditions included in the work completion information n.

[0101] When the XY positioner 4 receives a positioning signal e, it moves the stage 10 or local heating head according to the positioning signal e (k), and when the stage 10 or local heating head has moved to the specified position, it stops moving (m). When the movement is finished, the XY positioner 4 outputs a movement completion signal f to the welding controller 3 to indicate that the movement is complete (positioning step).

[0102] Upon receiving the movement completion signal f, the welding controller 3 outputs a head movement signal c to the actuator 35.

[0103] The actuator 35 moves the local heating head 32 toward the stage 10 in response to the head movement signal c (i). A heater tip 33 is attached to the tip of the local heating head 32, and as the local heating head 32 moves toward the plastic sheet 50, which is the mounting sheet, the heater tip 33 presses the mounting sheet toward the thermal recording body 70, which is the adhesive sheet.

[0104] This initiates the pressurization of the plastic sheet 50 by the heater tip 33 (pressurization step begins). If the local heating head 32 is a laser head, a laser is irradiated from the laser emitter at its tip toward the mounting sheet.

[0105] In this case, the mounting sheet is pressed against the thermal recording body 70, which is the adhesive sheet, by a plate that transmits the energy emitted from the local heating head. In a contact-type local heating head, pressurization is performed by the local heating head itself, while in a non-contact-type local heating head, pressurization is performed by a plate that transmits the energy emitted from the local heating head.

[0106] In particular, this plate can be made of glass. The glass plate can be borosilicate glass, quartz glass, or soda glass. Alternatively, a highly durable sapphire plate may be used. The release properties of the glass plate can be improved by surface treatment on one or both sides. The surface treatment can be chemical or physical. Chemical treatments include anti-glare treatment, silicone coating, fluorine coating, and wax coating. Physical treatments include matte finish and powder coating.

[0107] The strength of this pressure can be determined according to the materials of the adhesive sheet and mounting sheet, as well as the shape and material of the heater chip 33. At low pressure, the amount of indentation is reduced, which tends to reduce the welding area between the plastic sheet 50 and the thermal recording body 70. The local heating head may have a spring to control the strength of the pressure. Similarly, the plate through which the energy emitted from the local heating head is transmitted may also have a spring.

[0108] When the movement of the local heating head 32 is complete (j), the actuator 35 outputs a head movement completion signal d to the welding controller 3 while maintaining the pressurization by the local heating head 32 (in the case of a contact-type local heating head).

[0109] Upon receiving the head movement completion signal d, the welding controller 3 outputs a heating start signal a to the power supply 31. The local heating head is electrically connected to the power supply 31. In the pulse heat unit, the heater tip 33 is electrically connected to the power supply 31. In response to the heating start signal a, the power supply 31 supplies a heating current g to the heater tip 33 of the local heating head.

[0110] The heater tip 33 can be made of molybdenum. Molybdenum is hard, has moderate electrical resistance, and is suitable for heating. Other materials for the heater tip 33 include single metals such as tungsten, copper, and titanium, as well as various alloys containing molybdenum, tungsten, copper, and titanium. The tip of the heater tip 33 may also be coated and / or surface-treated by roughening.

[0111] The heater tip 33 has an integrated tip that contacts the workpiece, the mount sheet, and electrodes at both ends of the tip. The heater tip 33 generates heat through resistance heating corresponding to the supplied heating current g. As the heater tip 33 generates heat, the mount sheet in contact with the heater tip 33 is heated by heat transfer (start of heating step). If the local heating head is a laser head, the laser passes through the mount sheet, and a portion of the laser can be absorbed by the mounting sheet and converted into heat. Alternatively, the mount sheet may absorb a portion of the laser and convert it into heat.

[0112] The converted heat can be transferred to the mounting sheet and adhesive sheet facing each other. Heating can be performed by heating when the mounting sheet and adhesive sheet are in direct contact, or when the mounting sheet is in contact with one side of the intermediate layer and the adhesive sheet is in contact with the other side of the intermediate layer. The intermediate layer may be printed with infrared absorbing ink. The intermediate layer may also be a scattering layer. The intermediate layer may be a powder layer or coating layer of thermoplastic wax. The intermediate layer may be a urethane layer. The intermediate layer may also be a conductive layer.

[0113] The plastic sheet 50 is heated not only in the area in contact with the heater tip 33, but also around the area in contact with it, due to heat transfer. Therefore, the heat distribution on the plastic sheet 50 is not steep.

[0114] The shape of the tip of the heater tip 33 that contacts the mounting sheet can be rotationally symmetric with respect to the center of the tip. In particular, the shape of the tip of the heater tip 33 may have a curvature R when viewed, for example, from the y-direction in Figure 2. In this case, the curvature R can be constant.

[0115] When the tip shape of the heater tip 33 has a certain curvature R, its shape can be a spherical notch or a spherical band. In the case of a spherical band, the very tip of the heater tip 33 will be disc-shaped. These shapes can be formed by cutting the tip of the heater tip 33.

[0116] As described above, the tip of the heater tip 33 has a curved surface with curvature R, which allows for adjustment of the heat distribution during heating and release of heat history at the edges. The curvature R can be 15 mm or more and less than 20 mm. If the curvature R is less than 15 mm, the stress at the tip of the heater tip 33 will be too great, and there is a high possibility that noticeable welding marks will be formed on the plastic sheet 50 due to the pressure from the heater tip 33.

[0117] When the curvature R is 20 mm or more, the stress on the edges of the weld marks increases, making the weld marks more noticeable. To achieve good heat distribution, the heater tip 33 may be manufactured from two or more materials with different thermal conductivity characteristics.

[0118] Furthermore, because the tip of the heater tip 33 has a curvature R, the plastic sheet 50 will not be scratched or punctured even when the heater tip 33 is pressed against it.

[0119] Figure 5 is a temperature profile diagram showing an example of the temperature change of the heater tip over time during welding.

[0120] In Figure 5, the vertical axis represents the temperature of the heater chip 33, and the horizontal axis represents time.

[0121] In Figure 5, time t ０ This represents the time at which heating begins. When heating of the heater chip 33 begins at room temperature HTT, the temperature of the heater chip 33 rises in accordance with the heating current g.

[0122] The rise time from room temperature HTT to the welding temperature TEMP, i.e., (t １ -t ０ The heating current g can be flexibly set. The welding temperature TEMP is the temperature required to weld the mounting sheet to the adhesive sheet, and can be determined according to the materials of the adhesive sheet and the mounting sheet, as well as the shape and material of the heater tip 33.

[0123] The heating current g may be a pulse current. In this case, even if the instantaneous current value is constant, the integrated current value can be controlled by adjusting the pulse width. Control of the heating current g enables precise control on a millisecond basis. This makes it possible to achieve stepwise temperature increase rather than a rapid temperature rise.

[0124] A thermocouple 34 is provided at the tip of the heater chip 33. The thermocouple 34 outputs a voltage corresponding to the temperature at the tip of the heater chip 33 to the power supply 31 as a thermocouple voltage h. This allows the power supply 31 to grasp the temperature of the heater chip 33.

[0125] When the heating current g is a pulse current, the pulse width (current value) thereof can be adjusted using an appropriate feedback circuit (not shown) based on the temperature of the heater chip 33. The control method of this feedback circuit can be PID control. When the heating current g is a pulse current, the control can be realized by a switch circuit.

[0126] If the temperature corresponding to the thermocouple voltage h is likely to fall below the welding temperature TEMP, the power supply 31 widens the pulse width of the heating current g to the heater chip, and if the temperature is likely to exceed the welding temperature TEMP, the power supply 31 narrows the pulse width of the heating current g. By this control, the temperature of the heater chip 33 is controlled to be the welding temperature TEMP.

[0127] With such control, at time t in FIG. 5 １ as shown, when the temperature of the heater chip 33 rises to the welding temperature TEMP, the power supply 31 maintains the temperature of the heater chip 33 at the welding temperature TEMP from time t １ to time t ２ , and controls the heating of the heater chip 33 accordingly.

[0128] In the present specification, as shown in the time period (t ２ -t １ ) in FIG. 5, the time period during which the temperature of the heater chip 33 is maintained at the welding temperature TEMP is referred to as a heating holding time. The heating holding time (t ２ -t １ ) is the rise time, which is the time required for the temperature to rise to the welding temperature TEMP after the start of heating by the heater chip 33 (t１ -t ｏ It is longer than ).

[0129] Heating retention time (t ２ -t １ During this time, the pressurized state of the plastic sheet 50 by the heater tip 33 is maintained. In other words, the mounting sheet and the adhesive sheet remain facing each other throughout the heating and holding time.

[0130] Based on the thermocouple voltage h from the thermocouple 34, the power supply 31 controls the heating current g as described above, thereby controlling the temperature of the heater chip 33 for a heating hold time (t ２ -t １ During this process, the system controls the temperature to maintain the welding temperature (TEMP).

[0131] Figure 6 is a timing diagram showing the time relationship of the heater tip temperature obtained from (a) the heating start signal, (b) the target temperature, (c) the pulse width, and (d) the thermocouple voltage.

[0132] Using Figure 6, start of heating (time t ０ ) From the end of heating (time t ２ This section describes an example of the meticulous heating control performed up to that point.

[0133] As shown in Figure 6(a), when a heating start signal a is output from the welding controller 3 to the power supply 31, the power supply 31 supplies pulses of heating current g to the heater tip 33, as shown in Figure 6(c), in order to achieve the target temperature of the heater tip 33, as shown in Figure 6(b). This heating current g causes the temperature of the heater tip 33 to rise, as shown in Figure 6(d).

[0134] When the temperature of the heater tip 33 approaches the welding temperature TEMP, the power supply 31 adjusts the pulse width of the heating current g or the frequency of supplying the heating current g in accordance with the thermocouple voltage h, as shown in Figure 6(c), so that the temperature of the heater tip 33 does not exceed the welding temperature TEMP.

[0135] Through such adjustments, as shown in Figure 6(d), time t １In this process, once the temperature of the heater tip 33 reaches the welding temperature TEMP, the pulse width and supply frequency of the heating current g are adjusted based on the thermocouple voltage h, as shown in Figure 6(c), thereby maintaining the temperature of the heater tip 33 at the welding temperature TEMP for a time t, as shown in Figure 6(d). ２ Control it to maintain that level.

[0136] The power supply 31 may perform such control not only based on the temperature determined from the thermocouple voltage h, but also by taking into account the rate of temperature rise and the integrated value (heat quantity) of the heating current g.

[0137] In this way, the temperature of the heater tip 33 is heated and held at the welding temperature TEMP for a heating and holding time (t ２ -t １ After maintaining the above conditions, the power supply 31 stops supplying heating current g to the heater tip 33. This ends the heating by the heater tip 33 (end of heating step). If the local heating head is a laser, heating ends when the current from the power supply 31 stops or the shutter is turned OFF (end of heating step).

[0138] Heating retention time (t ２ -t １ ) can also be determined according to the material of the adhesive sheet and mounting sheet, and the shape and material of the heater tip 33, etc.

[0139] Even if heating by the heater tip 33 is stopped, the pressure applied to the plastic sheet 50 by the heater tip 33 remains in place until the cooling time described later has elapsed.

[0140] When the power supply 31 stops supplying the heating current g, it outputs a heating stop completion signal b to the welding controller 3.

[0141] After receiving the heating stop completion signal b, the welding controller 3 sets a cooling time (t) as shown in Figures 5 and 6(d). ３ -t ２ After the specified time has elapsed, a head movement signal c is output to the actuator 35.

[0142] Cooling time (t ３ -t ２The takt time can also be determined depending on the material of the adhesive sheet and mounting sheet, and the shape and material of the heater chip 33, but specifically, 0.5 seconds or more and 2 seconds or less is preferred. If it is longer than 2 seconds, the cycle time will be longer and productivity will decrease. If it is shorter than 0.5 seconds, cracks are likely to occur in the thermal recording body 70 and deterioration of the edges is likely to occur, leading to a decrease in appearance quality. This is thought to be because the thermal recording body 70 is rapidly cooled and cannot fully absorb the difference in thermal expansion coefficient with the plastic sheet 50.

[0143] The actuator 35, in response to the head movement signal c, moves the local heating head 32, which had been moving toward the stage 10, toward the stage 10 (i). This releases the pressure applied to the plastic sheet 50 by the heater tip 33 (end of pressure step). Similarly, in the case of welding with a laser welding machine, the plate is moved toward the stage 10.

[0144] Furthermore, in the case of non-contact heating such as laser welding, the plate may remain under pressure. In other words, the pressure step can be omitted. If the pressure step is omitted, the welding controller 3 recognizes that the series of processes is complete when the heating step is finished.

[0145] This process welds the mounting sheet, the plastic sheet 50, and the adhesive sheet, the thermal recording element 70, together. In other words, a fixed sheet stack is manufactured in which a portion of the plastic sheet 50 is welded to the thermal recording element 70.

[0146] When the movement of the local heating head 32 is completed (j), the actuator 35 generates a head movement completion signal d and outputs it to the welding controller 3.

[0147] When the welding controller 3 receives the head movement completion signal d, it recognizes that the series of welding operations are complete, refers to the work completion information n, and determines whether or not there are any unwelded anchor spots on the plastic sheet 50 (D1). If the pressurizing step is omitted, the welding controller 3 recognizes that the series of welding operations are complete when the heating step is completed. If it then determines that there are unwelded anchor spots (D1: Yes), it returns to the positioning step and repeats the steps from the positioning step onward (repetition).

[0148] On the other hand, if the welding controller 3 determines that there are no unwelded anchor spots (D1: No), and if the number of welded sheets has reached the specified number of sheets (D2: Yes), it terminates the process. If it has not reached the specified number of sheets (D2: No), it returns to the placement step with the newly obtained fixed sheet stack as a new adhesive sheet.

[0149] Next, a new mounting sheet is prepared to be welded to the new adhesive sheet, and the process from the placement step onward is repeated with the new adhesive sheet and the new mounting sheet (layering). This produces a fixed sheet stack in which a specified number of sheets are stacked and secured. When heat and pressure are applied to the entire surface of this fixed sheet stack, the sheets adhere to each other, forming a laminate.

[0150] At this stage, the sheets are fixed together with anchor spots, preventing misalignment and facilitating heat lamination. Cutting this laminate results in an authentication medium before personalization. The cut authentication medium is a laminate. By using a fixed sheet stack, an authentication medium before personalization can be obtained through heat lamination and subsequent cutting, making it possible to manufacture cards and sheets even in local factories with relatively lower security.

[0151] Personalized authentication media can be issued by using a laser to create a name, date of birth, and facial image on this authentication medium. When creating the facial image on the thermal recording medium with a laser, the anchor spots on the thermal recording medium may have different colored weld marks due to the heat effect during welding.

[0152] This welding mark can be formed at least in one location. This makes it possible to obtain a laminate of a thermal recording body and a plastic sheet having a welding mark at the anchor spot.

[0153] Figure 7 is a top view showing an example of a fixed sheet stack manufactured in this manner.

[0154] In the fixed sheet stack 40 illustrated in Figure 7, since the plastic sheet 50 is transparent, the thermal recording element 70 located beneath the plastic sheet 50 is visible. The individual pieces of the thermal recording element 70 illustrated in Figure 7 are rectangular in shape with beveled corners.

[0155] A welding mark 74 is formed on the corner of each piece of the thermal recording material 70 by pressing the tip of the heater chip 33 against it and heating it. In the case of laser welding, the welding mark 74 is formed by laser irradiation. Welding marks may also be present on the edges in addition to the corners. That is, each piece of the thermal recording material 70 has anchor spots on its corners and / or edges. The welding marks 74 are caused by thermal damage to the thermal recording material 70. The welding marks 74 can be a single point or multiple points. They may also be curves, straight lines, or a combination thereof. Furthermore, they may even be minute surfaces. These welding marks 74 can serve as watermarks.

[0156] The watermark may be identifiable. Identification can be done visually or by camera. The watermark may be an emblem, national flag, symbol, number, text, code, signature, or color scheme, or a combination thereof. The watermark allows for the identification of individual pieces of the thermal recording medium and prevents misuse for purposes other than its intended purpose.

[0157] The code may be a hash of unique data such as a serial number. The watermark of the welded mark, which is identified by visual inspection, may be invisible to the naked eye and visible only under specific lighting and / or through a filter. Specific lighting may include spotlights and blacklights. Filters may include color filters and polarizers. The watermark of the welded mark, which is identified by camera, may be visible under specific lighting and / or with a camera of specific sensitivity.

[0158] The specific illumination is monochromatic light. The specific sensitivity ranges are the visible, infrared, and terahertz wave ranges. The authentication medium may be formed by carbonizing a plastic sheet with the same emblem, flag, symbol, number, text, code, signature, or color scheme as a welded mark.

[0159] Carbonization of plastic sheets is easy to forge or tamper with, but it is highly visible. Conversely, welding marks are difficult to see, but they are difficult to forge or tamper with.

[0160] This enhances traceability and allows for more reliable detection of counterfeit goods. In addition, in laser welding, infrared absorbing ink may be printed on the plastic sheet 50 and / or the thermal recording body 70. This printing may be a geometric motif or a specific motif. This creates more complex welding marks, making it more difficult to manufacture counterfeit goods. The infrared absorbing ink can be a composition of an infrared absorber and a medium.

[0161] Infrared absorbers can have the property of absorbing light in the near-infrared region, which is between 700 nm and 1200 nm. Infrared absorbers can be phthalocyanines, cyanine dyes, or metal dithiolene complexes, either individually or in mixtures. Infrared absorbing inks can be printed using gravure printing, screen printing, or offset printing to produce infrared-absorbing ink prints. Infrared absorbing inks may further contain additives, dyes, and pigments.

[0162] Furthermore, since infrared-absorbing ink makes it easier to absorb laser light when printed, processing efficiency is also easily improved. The plastic sheet 50 is welded to the thermal recording body 70 at anchor spots. Because the infrared-absorbing ink is altered by the laser, it is possible to form complex motifs in which the printed motif of the infrared-absorbing ink and the trajectory or laser profile of the laser scan are superimposed. The infrared-absorbing ink print can be formed on the local heating head side of the mounting sheet and / or on the adhesive sheet side.

[0163] The anchor spots, which are the areas to be welded, are preferably the corners of the individual pieces of the thermal recording material 70. Alternatively, the anchor spots may be on the edges of the individual pieces of the thermal recording material 70. In other words, the anchor spots are located on the outer circumference of the individual pieces of the thermal recording material 70. At least two anchor spots are sufficient (for example, two of the four corners of the thermal recording material 70). The anchor spots are preferably located 2 mm to 10 mm from the outer edge of the thermal recording material 70 toward the center of the thermal recording material 70.

[0164] A pulse heat unit can be equipped with multiple heater tips 33. For example, when welding at four locations, if the pulse heat unit is equipped with only one heater tip 33, four welding operations will be required. However, if the pulse heat unit is equipped with four heater tips 33, welding at all four locations can be performed simultaneously.

[0165] The shape of the welding mark 74 recorded on the thermal recording element 70 is the shape of the tip of the heater tip 33.

[0166] Therefore, the shape of the welding mark 74 can be intentionally determined by the shape of the tip of the heater tip 33.

[0167] If the tip surface of the heater tip 33 is spherical, a circular welding mark 74 will be formed, as illustrated in Figure 7.

[0168] Figure 8 illustrates various welding marks that can be achieved depending on the shape of the tip of the heater chip.

[0169] The shape of the tip of the heater tip 33 that contacts the plastic sheet 50 can be arbitrarily determined depending on the application. For example, by making the shape of the tip an alphabet letter (e.g., A, B, etc.) or a symbol (e.g., a star, a heart, etc.), a welding mark 74 as shown in Figure 8(b) can be left.

[0170] Figure 8(a) is a plan view showing the thermal recording element 70 before welding, where the welding marks 74 are not yet present. Increasing the heating and holding time and / or the welding temperature makes it easier to leave these welding marks 74. Conversely, shortening the heating and holding time and / or lowering the welding temperature makes it less likely for these welding marks 74 to remain.

[0171] Furthermore, when welding is performed with a laser, the shape of the welded area 74 can be altered by the scan trajectory and the laser spot diameter. In other words, the shape of the welded area 74 can be determined by the laser scan trajectory and the laser spot diameter. The laser spot diameter can be defined by the second moment width, 1 / E2, or full width at half maximum. The second moment width is particularly commonly used.

[0172] The scan may trace the same path multiple times. The diameter of the scan path may also be smaller than the laser spot diameter. This helps prevent cracking of the thermal recording medium. The diameter of the scan path can be defined as the maximum diameter of the path.

[0173] As described above, with the thermal recording body 70 and the plastic sheet 50 facing each other, the heater tip 33 is heated by the actuator 35 under pressure from the mounting sheet side by the heater tip 33, thereby welding the mounting sheet and the adhesive sheet together to manufacture the fixed sheet stack 40. Alternatively, a laser can be irradiated from the mounting sheet side to weld the facing mounting sheet and adhesive sheet together.

[0174] (Experimental Result 1) Next, the experimental results of actually welding the plastic sheet 50 to individual pieces of the thermal recording body 70 according to the method described above will be explained as Example 1.

[0175] In Experiment Result 1, a 50 μm thick polycarbonate sheet (glass transition temperature: approximately 145°C) was used as the plastic sheet 50 to confirm the optimal condition range for the pulse heat unit. Experiments were also conducted to determine appropriate processing conditions for laser welding. In this experiment, a 50 μm thick polycarbonate sheet (glass transition temperature: approximately 145°C) was used as the plastic sheet 50 for the mounting sheet. The beam diameter was set to 2.0 mm, the scan trajectory diameter to 0.2 mm, and the laser power to 72 or 84 W. The rotation of the scan trajectory was varied to evaluate defects such as detachment and cracks of the thermal recording material immediately after welding, as well as discoloration of anchor spots after the formation of a facial image on the thermal recording material.

[0176] The laser head is equipped with a galvanometer scanner. The scanning trajectory was set to be circular. The laser head is a fiber laser. A specific example of a fiber laser is a carbon dioxide laser with a wavelength of 1070 nm. Experimental results showed that when the laser power was 72 W, setting the trajectory to 10 circles suppressed defects immediately after welding of the thermal recording material and discoloration after the formation of the facial image suppressed when the laser power was 84 W.

[0177] Furthermore, a heater tip 33 with a diameter of Φ2 mm and a tip with a curvature of R15 is used, and the pressure applied by the heater tip 33 driven by the actuator 35 is 5 N, and the rise time (t １ -t ０ ) 500 milliseconds, heating and holding time (t ２ -t １ Under conditions where the welding temperature TEMP and cooling time (t) are fixed at 1000 milliseconds, ３ -t ２ While changing the settings, heating was performed (heating step) to weld the thermal recording body 70 and the plastic sheet 50 together. The resulting fixed sheet stack 40 was then examined to determine whether welding was possible and to inspect the welding, and experiments were conducted on the processing conditions.

[0178] Figure 9 is a table showing the results obtained from the experiment.

[0179] In the experiment, polycarbonate was used as the plastic sheet.

[0180] The experiment was conducted for 12 cases, as shown in items 1 to 12 in Figure 9. Items 1 to 6 represent the cooling time (t ３ -t ２ This is a case where no cooling time (0 milliseconds) was set, and items 7 to 12 are cases where the cooling time (t ３ -t ２ This is the case where the time interval is set to 2000 milliseconds.

[0181] Items 1 through 6 each vary the welding temperature TEMP within the range of 200°C to 250°C. Similarly, items 7 through 12 each vary the welding temperature TEMP within the range of 200°C to 250°C.

[0182] Examples of temperature changes of the heater tip 33 measured during each welding process shown in Figure 9 are as shown in the timing diagram in Figure 6(d).

[0183] As shown in Figure 9 under "Post-Welding Evaluation (Welding, Appearance)," items 1 to 6, for which no cooling time was provided, showed poor welding or cracks in the appearance, indicating insufficient quality. On the other hand, among items 7 to 12, for which a cooling time of 2000 milliseconds was provided, items 7 to 10 showed good welding and appearance, indicating sufficient quality. However, for items 11 to 12, where the welding temperature TEMP was 245°C or higher, cracks were observed in the appearance, indicating insufficient quality.

[0184] From these results, the pressure applied by the heater tip 33 is 5N, and the rise time (t) is set to 5N. １ -t ０ ) 500 milliseconds, heating and holding time (t ２ -t １ Under conditions where the temperature was fixed at 1000 milliseconds, the results showed that both welding and appearance were good when the welding temperature TEMP was 220°C to 240°C and the cooling time was 2000 milliseconds, as shown in items 7 to 10.

[0185] These results are specific to certain conditions and do not directly and clearly indicate defects under other conditions; therefore, even under other processing conditions, an average engineer can find appropriate conditions within the scope of realistic consideration.

[0186] Next, the welding quality was compared with other welding methods.

[0187] Figure 10 is a table showing a comparison of the characteristics of various welding methods.

[0188] The welding methods used for comparison are, as shown in Figure 10, (1) thermal lamination, (2) laser, (3) pulsed heat, (4) ultrasonic, and (5) adhesive. (3) Pulsed heat corresponds to the welding method described in the first embodiment.

[0189] For each of the five welding methods used to obtain the fixed sheet stacks, the visual appearance and magnified photographs were taken after welding. Furthermore, the color development at the anchor spots was confirmed.

[0190] As a result, as shown in Figure 10, thermal lamination has a significant thermal impact on the thermal recording element 70, while welding causes less thermal damage to the thermal recording element 70.

[0191] Laser welding allows for faster processing speeds than pulsed heat welding. It is also possible to use both laser and pulsed heat welding in combination. In this case, pulsed heat can be applied to one side of the sheet while a laser is irradiated from the other side. Ultrasonic welding minimizes thermal damage. Adhesives cause the least thermal damage. The thermal recording element 70 deteriorates.

[0192] (3) The method for manufacturing the immobilized sheet stack 40, which includes a welding sequence by pulse heat, has processing stability and minimal thermal impact on the thermal recording body 70, as described in this embodiment.

[0193] As described above, in this embodiment, the local heating head is used to weld only at the anchor spots of the individual pieces of the thermal recording body 70.

[0194] Therefore, damage to the thermal recording element 70 is minimized, the welding quality is high, and the color development function of the thermal recording element 70 is maintained.

[0195] Furthermore, it was confirmed that the warping of individual pieces of the thermal recording element 70 can be suppressed by welding the plastic sheet 50 to the thermal recording element 70.

[0196] Thus, it has been shown that the pulsed heat welding method described above is suitable for fixing the thermal recording element 70 to the plastic sheet 50. Laser welding is also suitable.

[0197] Furthermore, the welding marks 74 formed by the heater tip 33 during welding using the pulsed heat method described above can also be used as watermarks.

[0198] Figure 11 shows an example of the relationship between the shape of the tip of the heater tip and the welding marks.

[0199] Figure 11 shows examples of a "cross-sectional view of a single heater tip (explanatory diagram)" a and a "welding mark (explanatory diagram)" b for a "shape where the entire surface is welded" α and a "shape where only the edges are welded" β.

[0200] In the first embodiment, as shown in Figure 7, for example, a configuration was described in which a plastic sheet 50 is welded to the thermal recording body 70 at the corners and edges of the individual pieces of the thermal recording body 70. The "shape where only the edges are welded" β in Figure 11 illustrates the "cross-sectional view of one heater chip (explanatory diagram)" a and the "welding mark (explanatory diagram)" b formed by the heater chip 33 whose tip has such a cross-section.

[0201] If the welding mark 74 is to be used as a watermark, the tip shape of the heater tip 33 should be the shape of the watermark shown in column b of "Welding Mark (Explanatory Diagram)," or the shape of a symbol or text, as illustrated in Figure 8.

[0202] As a result, when the plastic sheet 50 is welded to the four corners of the thermal recording body 70 from the state shown in Figure 8(a), a watermark can be formed on the plastic sheet 50 by a weld mark 74 in the shape of the tip of the heater tip 33, as shown in Figure 8(b). If such a weld mark 74 is to be used for visual authentication, it is desirable to increase the welding temperature and / or increase the heating and holding time so that the weld mark 74 remains clearly visible.

[0203] Subsequently, when a laser is irradiated onto the thermal recording body 70 to form a facial image and color is produced, watermarks of symbols or text corresponding to the shape of the heater chip 33 can be seen, as shown in Figure 8(c), where only the anchor spots exhibit different color production. Therefore, if a heater chip 33 with a convex shape only at the edge is used, it is possible to create welding marks where only the edges exhibit different color production.

[0204] In this way, the authenticity of the immobilized sheet stack 40 can be verified by the watermark that appears on the anchor spot according to the shape of the heater tip 33 and the trajectory of the laser scan.

[0205] In Figure 8(b), the weld marks 74 are shown as examples of watermarks consisting of common characters or symbols. However, the weld marks 74 are not limited to watermarks consisting of common characters or symbols; for example, they may be security motifs such as microtext or colored patterns. In this case, a higher level of anti-counterfeiting effect can be achieved.

[0206] (Second Embodiment) In the first embodiment, the welding of the plastic sheet 50 and the thermal recording element 70 by pulse heat was described. In the second embodiment, not only the welding of the thermal recording element 70 and the plastic sheet 50 is described, but also the welding of plastic sheets to each other and the fixing of plastic sheets to each other.

[0207] In the following description, elements similar to those already described in the first embodiment will be denoted by the same reference numerals to simplify the explanation, while differences from the first embodiment will be described in detail.

[0208] Figure 12 shows an example of a fixed sheet stack manufactured by the manufacturing apparatus 1 shown in Figure 4A, according to the sequence shown in Figure 4B.

[0209] Figure 12(a) is a perspective view illustrating four individual pieces of the thermal recording element 70.

[0210] Figure 12(b) is a perspective view illustrating a plastic sheet 51 having four holes 58 for fitting four individual pieces of thermal recording element 70 as illustrated in Figure 12(a). The shape and size of the holes 58 are the same as, or slightly larger than, the shape and size of the individual pieces of thermal recording element 70.

[0211] Figure 12(c) is a perspective view illustrating a plastic sheet 52 stacked on top of a plastic sheet 51. Plastic sheets 51 and 52 have the same external shape and size.

[0212] Figure 12(d) is a perspective view showing a state in which a plastic sheet 52 is stacked on a plastic sheet 51 into which four pieces of thermal recording element 70 are embedded, and a pulse heat unit is used to locally weld the plastic sheet 52 to the pieces of thermal recording element 70. In this case, the plastic sheet 52 corresponds to the mounting sheet, and the pieces of thermal recording element 70 correspond to the adhesive sheet.

[0213] Figure 12(e) is a perspective view of the primary fixed sheet stack 80, in which the plastic sheets 52 in Figure 12(d) are welded to each individual piece of the thermal recording element 70, and the corners of the plastic sheets 52 are further welded to the plastic sheets 51.

[0214] The plastic sheet 52 is welded to each corner of each individual piece of the thermal recording element 70, thereby forming four welding marks 74 on the plastic sheet 52 for each individual piece of the thermal recording element 70.

[0215] The plastic sheet 52 is also welded to the corners of the plastic sheet 51, so that four welding marks 75 are formed on the corners of the plastic sheet 52. In this case, the plastic sheet 52 corresponds to the mounting sheet, and the plastic sheet 51 corresponds to the adhesive sheet.

[0216] The sheet shown in Figure 12(e) will hereafter be referred to as the primary fixed sheet stack 80.

[0217] Figures 12(f) and 12(g) are perspective views illustrating the plastic sheets 53 and additional fixed sheet stack 85 stacked on the primary fixed sheet stack 80, respectively. The primary fixed sheet stack 80, the plastic sheets 53, and the additional fixed sheet stack 85 are identical in external shape and size.

[0218] The additional fixed sheet stack 85 consists of three plastic sheets 56, 55, and 54, each with the same external shape and size, stacked in this order from the top in the figure. The stack is heated from above plastic sheet 56, and the three plastic sheets 56, 55, and 54 are welded together as shown by the four welding marks 76 in Figure 12(g). In this case, plastic sheet 56 corresponds to the mounting sheet, and plastic sheets 55 and 54 correspond to the adhesive sheets.

[0219] A primary fixing sheet stack 80 is placed on top of such an additional fixing sheet stack 85, and a plastic sheet 53 is further stacked on top of the primary fixing sheet stack 80. As illustrated in Figure 12(h), the plastic sheet 53 is heated from above, and the plastic sheet 53, primary fixing sheet stack 80, and additional fixing sheet stack 85 are welded together.

[0220] In this case, the plastic sheet 53 corresponds to the mounting sheet, and the primary fixing sheet stack 80 and the additional fixing sheet stack 85 correspond to the adhesive sheets. In this way, the secondary fixing sheet stack 90, which is welded to the layer opposite each other, is heat-laminated and then cut to create cards or pages.

[0221] After the secondary fixed sheet stack 90 is heat-laminated, it is cut to the size of a card or page to be used as an authentication medium. As mentioned above, welding marks corresponding to the shape of the tip of the heater chip 33 and the trajectory of the laser scan remain on the anchor spots that were heated by the local heating head.

[0222] If these welding marks are present on the product after cutting, they will affect its appearance. Therefore, the welding locations of the primary and secondary fixed sheet stacks 80 and 90 may be placed outside the area of ​​the sheet that will become the final product. This ensures that the welding marks of the primary and secondary fixed sheet stacks 80 and 90 do not remain on the final product.

[0223] The following is an example of leaving welding marks outside the area of ​​the sheet that will become the final product.

[0224] Figures 13(a) to 13(d) are perspective views of the primary immobilization sheet stack showing several patterns of the locations of welding marks remaining on the primary immobilization sheet stack.

[0225] As shown in Figures 13(a) to (d), the areas where welding marks 75 remain are all located on the outermost edge of the primary immobilized sheet stack 80. The outermost edge of the primary immobilized sheet stack 80 is an area that is not used for the final product.

[0226] Figures 14(a) to 14(d) are perspective views of a secondary immobilization sheet stack showing several patterns of welding marks remaining on the secondary immobilization sheet stack.

[0227] As shown in Figures 14(a) to (d), the areas where welding marks 77 remain are all located on the outermost edge of the secondary immobilization sheet stack 90. ​​The outermost edge of the secondary immobilization sheet stack 90 is an area that is not used for the final product.

[0228] In this way, the primary fixed sheet stack 80 is welded so that a welding mark 75 remains on the outermost edge, and the secondary fixed sheet stack 90 is welded so that a welding mark 77 remains on the outermost edge. This makes it possible to manufacture a final product in which neither the appearance nor the function of the thermal recording element 70 is impaired.

[0229] Furthermore, since the welding marks 75 and 77 remain on or near the surface of the fixed sheet stack, they may affect the appearance of the final product. On the other hand, in the case of layers far from the surface, such as the fixed sheet stack 85, the welding marks 76 are less likely to affect the appearance of the final product.

[0230] Therefore, for layers far from the surface layer, such as the additional fixed sheet stack 85, welding marks 76 may be left in locations other than the outer periphery, as long as it does not affect the function of the thermal recording body 70.

[0231] Furthermore, as mentioned above, when manufacturing a final product such as an identification card from the secondary fixed sheet stack 90, the secondary fixed sheet stack 90 is cut to a predetermined size. The welding locations to the primary fixed sheet stack 80 and the secondary fixed sheet stack 90 are determined so that the welding marks 75 and 77 are located on the cutting line.

[0232] Figure 15 is a perspective view of the secondary immobilization sheet stack to show the relationship between the cutting line and the welding marks.

[0233] Figure 15(a) is a perspective view of a secondary fixed sheet stack 90, as shown in Figure 14(a), with cross-shaped cutting lines S1 and S2 perpendicular to each other at the center point of the secondary fixed sheet stack 90, in order to divide the stack into four parts after heat lamination. These cutting lines can be formed by differences in printing or the unevenness of the sheets. In the example shown in Figure 15(a), there are no welding marks 77 on the cutting lines S1 and S2.

[0234] Figure 15(b) is a perspective view of a secondary immobilization sheet stack 90 that has been marked with cutting lines S1 and S2, similar to those in Figure 15(a), in order to divide the secondary immobilization sheet stack 90 shown in Figure 14(b) into four sections. In the example shown in Figure 15(b), of the six welding marks 77 left on the outer circumference of the secondary immobilization sheet stack 90, two welding marks 77 (#1) and (#2) are located at both ends of the cutting line S1.

[0235] Figure 15(c) is a perspective view of the secondary immobilization sheet stack 90 shown in Figure 14(c), with cutting lines S1 and S2 marked in the same way as in Figure 15(a) to divide the stack into four sections. In the example shown in Figure 15(c), the welding marks 77 are not on the cutting lines S1 and S2, but are located at the four corners.

[0236] Figure 15(d) is a perspective view of a secondary immobilization sheet stack 90 that has been marked with cutting lines S1 and S2, similar to Figure 15(a), in order to divide the secondary immobilization sheet stack 90 shown in Figure 14(d) into four sections. In the example shown in Figure 15(d), of the 10 welding marks 77 left on the outer circumference of the secondary immobilization sheet stack 90, two welding marks 77 (#1) and (#2) are located at both ends of the cutting line S1.

[0237] If the secondary fixed sheet stack 90 is divided into four parts, the primary fixed sheet stack 80 that constitutes the secondary fixed sheet stack 90 is also divided into four parts.

[0238] Figure 16(a) is a perspective view of the primary fixed sheet stack 80 shown in Figure 13(a), with cross-shaped cutting lines S1 and S2 perpendicular to the center point of the primary fixed sheet stack 80, in order to divide the primary fixed sheet stack 80 into four sections. In the example shown in Figure 16(a), there are no welding marks 75 on the cutting lines S1 and S2, but they are located at the corners.

[0239] Figure 16(b) is a perspective view of a primary fixed sheet stack 80 that has been marked with cutting lines S1 and S2, similar to those in Figure 16(a), in order to divide the primary fixed sheet stack 80 shown in Figure 13(b) into four sections. In the example shown in Figure 16(b), of the eight welding marks 75 left on the outer circumference of the primary fixed sheet stack 80, two welding marks 75 (#1) and (#2) are located at both ends of the cutting line S1, and two welding marks 75 (#3) and (#4) are located at both ends of the cutting line S2.

[0240] Furthermore, as mentioned above, welding marks in layers far from the surface layer do not affect the appearance of the final product. In other words, since appearance is not a concern, welding can be performed on layers far from the surface layer, even in areas used in the final product, for purposes such as preventing detachment of the substrate or fixing multiple substrates together. An example of this will be explained using Figure 17.

[0241] Figures 17(a) to 17(d) are perspective views showing examples of a primary fixed sheet stack 80 in which individual pieces of thermal recording material 70 are embedded in a plastic sheet 51, and a plastic sheet 52 is also welded around the individual pieces of thermal recording material 70.

[0242] In all of the primary fixed sheet stacks 80 illustrated in Figures 17(a) to (d), plastic sheets 52 are welded to the plastic sheet 51 surrounding the individual pieces of thermal recording material 70 at multiple points in order to prevent deformation of the individual pieces of thermal recording material 70 during lamination, and the remaining welding marks 75a are illustrated.

[0243] Figure 17(a) shows the case where, in the primary fixed sheet stack 80 shown in Figure 13(a), a plastic sheet 52 is welded to the plastic sheet 51 so as to surround each individual piece of thermal recording element 70. Weld marks 75a remain surrounding each individual piece of thermal recording element 70.

[0244] Figure 17(b) shows the case where, in the primary fixed sheet stack 80 shown in Figure 13(b), a plastic sheet 52 is welded to the plastic sheet 51 so as to surround each individual piece of thermal recording element 70. Weld marks 75a remain surrounding each individual piece of thermal recording element 70.

[0245] Figure 17(c) shows the case in the primary fixed sheet stack 80 shown in Figure 13(a) in which the plastic sheet 52 is welded to the plastic sheet 51 only around the two diagonally opposite corners of each individual piece of thermal recording element 70. Unlike Figure 17(a), the weld marks 75a do not surround each individual piece of thermal recording element 70.

[0246] Figure 17(d) shows the case in the primary fixed sheet stack 80 shown in Figure 13(b) in which the plastic sheet 52 is welded to the plastic sheet 51 only around the two diagonally opposite corners of each thermal recording element 70. Unlike Figure 17(b), the weld marks 75a do not surround each individual piece of thermal recording element 70.

[0247] Such welding can provide auxiliary fixation for the individual pieces of the thermal recording element 70.

[0248] Figure 18(a) is a perspective view of the primary fixed sheet stack 80 shown in Figure 17(a), with cross-shaped cutting lines S1 and S2 perpendicular to the center point of the primary fixed sheet stack 80, in order to divide the primary fixed sheet stack 80 into four sections. In the example shown in Figure 18(a), there are no welding marks 75 or welding marks 75a on the cutting lines S1 and S2.

[0249] Figure 18(b) is a perspective view of a primary fixed sheet stack 80 that has been divided into four sections by cutting lines S1 and S2, similar to those in Figure 18(a), as shown in Figure 17(b). In the example shown in Figure 18(b), of the eight welding marks 75 left on the outer circumference of the primary fixed sheet stack 80, two welding marks 75 (#1) and (#2) are located at both ends of the cutting line S1, and two welding marks 75 (#3) and (#4) are located at both ends of the cutting line S2, but there are no welding marks 75a on the cutting lines S1 and S2.

[0250] The welding marks 75a are formed to prevent deformation of individual pieces of the thermal recording material 70 during lamination, and are therefore formed so as not to be located on the cutting lines S1 and S2.

[0251] The second embodiment has been described above, but the welding, number of sheets, and combinations mentioned above are merely examples, and the location, number, and combination of sheets of welding are not limited to these examples.

[0252] As described above, according to the manufacturing method of the second embodiment, not only the welding of the thermal recording element and the plastic sheet, but also the welding of plastic sheets to each other can be achieved with a single manufacturing apparatus. Therefore, even if the number of sheets to be welded increases, processing can be carried out with a compact manufacturing apparatus without requiring additional installation space.

[0253] (Third Embodiment) A method for manufacturing a fixed sheet stack and a manufacturing apparatus according to a third embodiment of the present invention will be described.

[0254] Figure 19 is a functional block diagram showing an example of the functional configuration of a manufacturing apparatus according to the third embodiment.

[0255] Figure 20 is a conceptual diagram showing each step of the manufacturing method carried out by the manufacturing apparatus according to the third embodiment.

[0256] The manufacturing apparatus 1A according to this embodiment includes a robot arm 5, a welding controller (programmable logic controller) 3, an XY positioner 4, a stage 10, a pick-and-place machine 20, a suction unit 21, and a welding machine 30. When the welding machine 30 is a heater unit, the tip of the local heating head 32 is a heater tip 33.

[0257] As mentioned above, the heater tip 33 is part of the local heating head 32, but in Figure 19, for the sake of explanation, the local heating head 32 and the heater tip 33 are shown separately.

[0258] (Stage) Figure 21 is a perspective view illustrating an example of the stage configuration in the third embodiment.

[0259] The stage 10 is moved in the xy plane in the figure by an XY positioner 4 controlled by a welding controller 3, and is made of a flat metal plate as shown in Figure 21(a), with positioning pins 11 provided at the corners. The positioning pins 11 are for positioning the plastic sheets 50 and 60 placed on the stage 10, as shown in (Sa1).

[0260] The plastic sheets 50 and 60 also have holes 57 and 62 drilled in them at positions corresponding to the positioning pins 11. Therefore, by passing the positioning pins 11 through the holes 57 and 62, the plastic sheets 50 and 60 are positioned at predetermined positions on the stage 10.

[0261] The welding machine 30 can be installed on the lower side (-z side) of the stage 10. The heater unit is equipped with a plurality of local heating heads 32. The tips of the local heating heads 32 are heater tips 33. The stage 10 is provided with holes 12 for passing the heater tips 33 through.

[0262] In other words, when a local heating head for contact is used as the welding machine 30, a hole 12 is provided for heating by contact. When laser welding is used as the welding machine 30, a window is provided to allow the laser to pass through.

[0263] In other words, when a non-contact local heating head is used as the welding machine 30, a window is provided for injecting heating energy. To transmit heating energy from the welding machine 30 via contact, a hole can be provided. Alternatively, the welding machine 30 may be installed on the upward side (+z side), in which case a pick-and-place machine presses individual pieces of the thermal recording material onto the plastic sheet from below.

[0264] The number of holes 12 in stage 10 can be determined according to the number of heater tips 33. For example, if there are four heater tips 33, then the number of holes 12 in stage 10 can also be four. In the following explanation, the welding machine 30 will be described as having four heater tips 33 as an example.

[0265] Stage 10 may also be provided with a suction device (not shown) for fixing the plastic sheets 50, 60. If a suction device is provided, it is controlled by the welding controller 3.

[0266] (Pick and Place Machine) Figure 22 is a perspective view showing an example of the configuration of a pick and place machine in the third embodiment.

[0267] The pick-and-place machine 20 is positioned as an arm-end tool, such as an EOAT (End Of Arm Tooling) on ​​the arm of the robot arm 5, and is located on the upper side (+z side) of the stage 10. The robot arm 5 can be implemented as, for example, the arm of a multi-axis robot. Alternatively, it may be a collaborative robot that safely stops when it comes into contact with a person or object. As shown in Figure 4, the pick-and-place machine 20 has a suction part 21 and a pressure receiving part 22 on its bottom surface 23.

[0268] The suction part 21 is for adsorbing individual pieces of the thermal recording material 70, and can generally be implemented with a suction cup connected to a vacuum pump. The suction part 21 can be an adsorption plate with numerous holes in a metal plate.

[0269] The pressure receiving section 22 receives pressure from the heater tip and the glass plate. The pressure receiving section 22 may also be equipped with a heater. This broadens the range of welding conditions. Heating by the heater should be below the glass transition temperature of the plastic sheet. Specifically, it can be between 40°C and 80°C.

[0270] Figure 23 is a perspective view showing an example of a portion of the configuration of a roll of thermal recording material.

[0271] As illustrated in Figure 23, the thermal recording body 70 has a leuco layer 71 laminated on top of a polycarbonate layer 72, which is formed by layering multiple thermal recording layers containing leuco dyes and insulating layers. The polycarbonate layer 72 is thermoplastic.

[0272] Such thermal recording media 70 are stored in a roll. The individual pieces of thermal recording media 70 that the suction part 21 adheres to are cut from the thermal recording media 70 in this roll state. The individual pieces cut from the thermal recording media 70 in the roll state curl.

[0273] Therefore, having only one suction part 21 on the bottom surface 23 of the pick-and-place machine 20 is insufficient, and it is desirable to have at least four, as illustrated in Figure 22. The suction parts 21 can be realized, for example, by suction cups. The number of suction parts 21 placed on the bottom surface 23, their placement, suction force, etc., are adjusted according to the size and thickness of the individual pieces of the thermal recording material 70.

[0274] As a result, the pick-and-place machine 20 can stably hold individual pieces of the thermal recording body 70, even those with strong curls, using the suction unit 21, and reliably transport them to a predetermined position using the robot arm 5.

[0275] Furthermore, the suction part 21 can also be replaced with a porous vacuum plate instead of a suction cup. When a porous vacuum plate is used, multiple suction holes connected to a suction device (not shown) are uniformly provided on the bottom surface 23 of the pick-and-place machine 20. The suction force from the suction holes allows the suction part 21 to evenly attract and hold the entire individual piece of the thermal recording body 70 across the entire surface of the bottom surface 23.

[0276] As a result, the pick-and-place machine 20 can hold individual pieces in a flat state with minimal stress on the pieces due to the dispersed suction force of the suction section 21, while suppressing curling.

[0277] Although the thermal recording element 70 is fragile, by using a vacuum plate as the suction part 21, the individual pieces can be held flat without breaking, with minimal stress on the individual pieces.

[0278] The robot arm 5 transports the pick-and-place machine 20, which has picked up individual pieces of the thermal recording body 70 by the suction unit 21, to the position of the through-hole 61 in the xy plane. Simultaneously, the XY positioner 4 moves the stage 10 in the xy plane, aligning the position of the hole 12 so that it is directly above the local heating head 32, and specifically directly above the heater tip 33.

[0279] Then, when the center of the bottom surface 23 of the pick-and-place machine 20 is directly above the center of the through-hole 61, the robot arm 5 descends (moves in the -z direction) and places the individual pieces of the thermal recording body 70 into the through-hole 61.

[0280] Then, the welding machine 30 also rises (moves in the +z direction), and the heater tip 33 passes through the hole 12, pressing the pressure receiving section 22 while sandwiching the individual pieces of the plastic sheet 50 and the thermal recording body 70 between it and the pressure receiving section 22.

[0281] Thus, the pressure receiving section 22 receives pressure from the welding machine 30. Furthermore, as will be described later, the pick-and-place machine 20 also receives heat from the welding machine 30. Therefore, the pick-and-place machine 20 is constructed of a metal block or the like so that the pressure receiving section 22 has sufficient rigidity and heat capacity. In addition, the pick-and-place machine 20 may be appropriately equipped with a cooler to cool the heat generated by the welding machine 30.

[0282] (Welding machine) The welding machine 30 is installed on the lower side (-z side) of the stage 10. The welding machine 30 can be implemented using various welding methods, but the following explanation will use the case where four local heating heads 32 are used as an example.

[0283] Alternatively, laser irradiation can be used as the welding method. In this case, a window that allows the laser to pass through may be placed at the hole 12. The welding machine 30 may also be located on the upper side (+z side) of the stage 1. In this case, the pick-and-place machine 20 places the thermal recording body 70 into the fixed sheet stack from below.

[0284] As described above, when the welding machine 30 rises in the +z direction and the heater tip 33 of the local heating head 32 passes through the hole 12, pressing the pressure receiving section 22 while sandwiching the individual pieces of the plastic sheet 50 and the thermal recording body 70 between it and the pressure receiving section 22, the welding machine 30, while maintaining the pressure applied by the heater tip 33, supplies current from the power supply 31 to the heater tip 33 and starts heating the heater tip 33.

[0285] Furthermore, as heating begins, the pick-and-place machine 20 stops the individual piece adsorption operation by the adsorption unit 21.

[0286] When heating of the heater tip 33 begins, the temperature of the heater tip 33 rises. The heater tip 33 is equipped with a thermocouple 34, and the welding controller 3 determines the temperature of the heater tip 33 from the output voltage from the thermocouple 34.

[0287] When the temperature of the heater tip 33 rises to the welding temperature, the welding controller 3 controls the heating of the welding machine 30 to maintain the temperature of the heater tip 33 at the welding temperature for a predetermined time (hereinafter referred to as the "heating holding time").

[0288] The welding temperature is the temperature required to weld the mounting sheet (in this case, the plastic sheet 50) to the adhesive sheet (in this case, the individual pieces of the thermal recording element 70), and can be determined according to the materials of the adhesive sheet and the mounting sheet, as well as the shape and material of the heater chip 33.

[0289] The heating time until the heater tip 33 reaches the welding temperature, as well as the heating and holding time, can also be determined according to the materials of the adhesive sheet and mounting sheet, and the shape and material of the heater tip 33.

[0290] Subsequently, once the heater tip 33 maintains the welding temperature and the heating holding time has elapsed, the welding controller 3 stops heating while still pressurizing the individual pieces of the thermal recording body 70 and controls the welding machine 30 to maintain that state for a predetermined time (hereinafter referred to as the "cooling time").

[0291] This causes the temperature of the mounting sheet and the adhesive sheet to decrease. After the cooling time has elapsed, the individual pieces of the thermal recording body 70 are fixed to the polycarbonate sheet 50. After the cooling time has elapsed, the welding controller 3 moves the robot arm 5, which has the pick-and-place machine 20 positioned on its arm, to the location of the individual pieces of the thermal recording body 70 so that the pick-and-place machine 20 can hold the next individual piece.

[0292] Furthermore, the welding controller 3 drives the XY positioner 4 to move the stage 10 to the next placement position.

[0293] For example, when the thickness of the mounting sheet (plastic sheet 50) is 100 μm and the thickness of the adhesive sheet (thermal recording body 70) is 50 μm, the heating time, welding temperature, and cooling time are 10 to 300 milliseconds, 200 to 250°C, and 100 to 500 milliseconds, respectively.

[0294] The welding machine 30 fixes individual pieces of the thermal recording element 70 to the plastic sheet 50 by welding through this process.

[0295] As illustrated, if the welding machine 30 is equipped with four local heating heads 32, then the stage 10 is provided with four holes 12 accordingly. With this configuration, welding can be performed at four locations simultaneously. Thus, by providing multiple local heating heads 32, welding can be performed at multiple locations simultaneously, improving work efficiency and increasing productivity.

[0296] In addition to the pulse heat unit, the welding machine 30 can also be a laser welding machine, an ultrasonic device, or an induction heater. The welding machine 30 is equipped with a local heating head. Local heating heads can be classified into contact type and non-contact type. Specific examples of contact type local heating heads are pulse heat heads and horns of ultrasonic welding machines. The horn of an ultrasonic welding machine is supplied with an ultrasonic drive voltage from an oscillator corresponding to the power supply of the pulse heat unit or laser welding device.

[0297] Specific examples of non-contact local heating heads include laser heads and induction heating coils. When the attached sheet is a thermal recording material, the thermoplastic resin layer on its outermost surface melts and fuses with the plastic sheet of the mounting sheet that is in contact with it. The thermoplastic resin on the outermost surface may have properties that absorb laser light.

[0298] When the laser wavelength is infrared, the thermoplastic resin on the outermost surface of the thermal recording material can be made infrared absorbent. This allows for efficient absorption of laser energy and conversion into heat. The thermal recording material may also be equipped with an insulating layer to suppress damage to the color-developing layer. This insulating layer may be the outermost thermoplastic resin layer itself. Such a thermoplastic resin layer can have a thickness of 25 μm or more and 75 μm or less.

[0299] The welding machine 30 can be fitted with any of these methods. Furthermore, two different welding methods can be used for the anchor spots. Different welding methods may be used for welding the thermal recording material and other parts, or the same welding method may be used.

[0300] In cases where different welding methods are used for welding the thermal recording material and other materials, the welding machine 30 for the thermal recording material may use a pulse heat unit and / or a laser welding machine, while for other welding applications, an ultrasonic welding machine, induction heating machine, or metal heater may be used. A different welding method may also be used for welding the thermal recording material.

[0301] For example, a combination of laser welding and pulsed heat welding can be used. In this case, anchor spots that form a watermark on the weld can be welded using the pulsed heat method with a heat hip, while anchor spots that do not form a watermark on the weld can be welded using the laser welding method with a laser head.

[0302] If the same welding method is used for welding the thermal recording material and for other applications, the same type or the same equipment can be used for both.

[0303] The aforementioned pulsed heat power supply method allows for precise localized heating by supplying a controlled current to the localized heating head 32 and heating the heater chip 33.

[0304] Ultrasonic welding machines utilize the principle of locally heating and melting resin using frictional heat generated by high-frequency vibrations. They can be applied to short-time bonding and, depending on the size of the transducer, to welding small areas, but they have limitations in terms of material and thickness.

[0305] Laser welding utilizes the principle of localized heating in a light-absorbing layer by irradiating with a near-infrared laser, enabling precise control, non-contact processing, and joining of transparent materials. However, the laser conditions must be set according to the material.

[0306] When the welding machine 30 uses a laser welding method, the stage 10 needs to have holes 12 through which the laser can pass. The size and angle of the holes 12 are adjusted according to the method used, such as when the stage 10 is moved or when the laser is scanned with a galvanometer mirror.

[0307] The hot stamping method utilizes the principle of welding by directly pressing a small heating head, such as a heat-sealing head, against the material using pressure and heat. This method allows for simple and stable heating, as well as precision machining by miniaturizing the heating plate. While this method is highly reliable, it requires preheating and continuous heating.

[0308] The high-frequency induction heating method utilizes the principle of heating and welding a conductive material using electromagnetic induction. It allows for localized heating and can be applied to welding plastic sheets by adding a conductive material.

[0309] The pressure receiving section 22 of the pick-and-place machine 20 is also necessary when a welding method other than a pulse heater method equipped with a heater tip is applied to the local heating head 32, and its shape and material shall be appropriate for each welding method.

[0310] Next, the operation of the manufacturing apparatus 1 for the fixed sheet stack according to the third embodiment configured as described above will be explained.

[0311] In the manufacturing method according to this embodiment, individual pieces of thermal recording element 70 are fixed to a plastic sheet 50 by welding according to steps Sa1 to Sa4 shown in Figure 20 to produce a fixed sheet stack. Steps Sa1 to Sa4 will be described below with reference to Figure 20.

[0312] (Sa1) A plastic sheet 50, which is a mounting sheet, is placed on the stage 10, and a plastic sheet 60 having a through-hole 61 is placed on top of it.

[0313] A positioning pin 11 is provided on the stage 10, and correspondingly, holes 57 and 62 are also provided in the plastic sheets 50 and 60. By passing the positioning pin 11 through the hole 57 in the plastic sheet 50 and the hole 62 in the plastic sheet 60, the plastic sheets 50 and 60 can be positioned at predetermined locations on the stage 10.

[0314] The plastic sheet can be positioned in a predetermined location by using a backing plate or robotic positioning, thus eliminating the need for the through-hole 61 and positioning pins 11.

[0315] At this stage, the two plastic sheets 50 and 60 can also be welded together. Alternatively, the two plastic sheets 50 and 60 may be welded together in advance, and then fixed in place using a suction device (not shown) installed on the stage 10.

[0316] (Sa2) When two plastic sheets 50 and 60 are placed on the stage 10, the pick-and-place machine 20, which is located above the stage 10 (in the +z direction), descends to place individual pieces of the thermal recording body 70, which is an adhesive sheet, into the through-holes 61 of the plastic sheet 60.

[0317] Then, the welding machine 30 rises (moves in the +z direction), and each heater tip 33 of the four local heating heads 32 passes through the hole 12, pressing the pressure receiving section 22 while sandwiching the individual pieces of the plastic sheet 50 and the thermal recording body 70 between them.

[0318] (Sa3) In this state, the four local heating heads 32 are heated by the current from the power supply 31, thereby welding the plastic sheet 50 and the individual pieces of the thermal recording body 70 together.

[0319] (Sa4) This creates a fixed sheet stack 80 in which individual pieces of thermal recording material 70 are welded to a plastic sheet 50. This fixed sheet stack 80 is then laminated, for example, sandwiched between other plastic sheets, and then integrated by thermal lamination, cut to the size of an information recording material, and used as an information recording material such as an ID card or passport.

[0320] As described above, according to the manufacturing method and manufacturing apparatus 1 of the third embodiment, the step of arranging individual pieces by the pick-and-place machine 20 and the welding sequence of individual pieces by the welding machine 30 can be performed simultaneously. This makes it possible to achieve the following advantages over the conventional technology.

[0321] Figure 24 is a conceptual diagram showing each step of the manufacturing method for a conventional immobilized sheet stack.

[0322] In conventional technology, the pick-and-place machine and welding machine for positioning the individual pieces of the thermal recording body 70 and the plastic sheet 50 are both installed above the stage 10. Therefore, the space utilization rate above the stage 10 is quite high.

[0323] Therefore, as shown in Figure 24, (a) the placement step and (b) the welding sequence are not performed simultaneously but sequentially. Furthermore, the stage 10 needs to be provided with, for example, suction holes 13 for adsorbing the plastic sheet 60, which are connected to a vacuum machine, and suction holes 14 for adsorbing individual pieces of the thermal recording body 70, making the configuration of the stage 10 complex.

[0324] In the conventional technology, after the arrangement step (a) shown in Figure 24, in the welding sequence (b), the heater tip 33 descends from above the stage 10 and heats the plastic sheet 50 while applying pressure. Therefore, the stage 10 also serves as the pressure receiving part for the heater tip 33, and thus needs to have sufficient thickness and rigidity to withstand the pressure, which limits the weight reduction of the stage 10.

[0325] In contrast, according to the control method and control device 1 of this embodiment, since the pick-and-place machine 20 and the welding machine 30 are provided above and below the stage 10, respectively, the step of placing individual pieces by the pick-and-place machine 20 and the welding sequence of individual pieces by the welding machine 30 can be performed simultaneously.

[0326] This allows for an improvement in production speed from a manufacturability standpoint.

[0327] Furthermore, from a quality standpoint, since the individual pieces of the thermal recording element 70 can be directly positioned using the robot arm 5, high-precision positioning is possible with suppressed misalignment and positioning errors of the individual pieces. Therefore, accurate positioning of the individual pieces and uniform, stable fixing can prevent positional errors and peeling in subsequent processes.

[0328] Furthermore, by holding the curled pieces of the thermal recording body 70 after cutting with the robot arm 5 and welding them together at the same time as positioning, it is possible to prevent the pieces from lifting or shifting. This reduces the load on the pieces and suppresses the occurrence of cracks and breaks in the pieces.

[0329] Furthermore, since the individual pieces can be welded while being held in a smooth state, there is no difference in temperature due to uneven pressure, and stable fixing of the thermal recording element 70 becomes possible. As a result, the occurrence of defective products can be suppressed and a high yield rate can be achieved.

[0330] From the standpoint of simplifying the equipment, since it is no longer necessary to temporarily fix the thermal recording element 70 to the stage 10 by suction as in conventional technology, it becomes unnecessary to provide a structure for suction fixing on the stage 10, and the structure of the stage 10 can be simplified.

[0331] Furthermore, since the pick-and-place machine 20 has the function of receiving pressure from the heater tip 33, the stage 10 does not need to withstand pressurization, which reduces constraints on thickness and rigidity, making it possible to lighten the stage 10, improve maintainability, and reduce costs compared to conventional technology.

[0332] Furthermore, from the perspective of product adaptability, the simplification of stage 10 makes it possible to handle individual pieces of various sizes with a single stage 10, and also reduces the burden associated with switching equipment to accommodate various product types.

[0333] As described above, the control method and control device 1 according to this embodiment make it possible to manufacture high-quality fixed sheet stacks at low cost and with high production efficiency using a simplified equipment configuration that is also highly adaptable to products.

[0334] (Fourth Embodiment) A method for manufacturing a fixed sheet stack and a manufacturing apparatus according to a fourth embodiment of the present invention will be described.

[0335] Figure 25 is a conceptual diagram showing each step of the manufacturing method carried out by the manufacturing apparatus according to the fourth embodiment.

[0336] In the manufacturing apparatus according to the third embodiment, a pick-and-place machine 20 was provided above the stage 10 and a welding machine 30 was provided below the stage 10. However, in the manufacturing apparatus according to the fourth embodiment, as shown in Figure 25, the opposite is true compared to the manufacturing apparatus according to the third embodiment: a welding machine 30' is provided above the stage 10' and a pick-and-place machine 20' is provided below the stage 10.

[0337] The functional block diagram of the manufacturing apparatus according to this embodiment is obtained by replacing Stage 10 with Stage 10', Pick-and-Place Machine 20 with Pick-and-Place Machine 20', and Welding Machine 30 with Welding Machine 30' in Figure 19.

[0338] Even with a manufacturing apparatus of this configuration, the arrangement of individual pieces of the thermal recording element 70 and their fixing to the plastic sheet 50 can be performed simultaneously.

[0339] (Stage) In the manufacturing apparatus of this embodiment, as shown in Figure 25 (Sb1), the pick-and-place machine 20' transports and places individual pieces of the thermal recording body 70 from below the stage 10', so the stage 10' is provided with a through-hole 15 through which the pick-and-place machine 20' can pass.

[0340] Furthermore, on stage 10', the plastic sheets 60 and 50 are stacked in order from the bottom up, in the opposite direction to stage 10, and the heater tip 33 of the welding machine 30' faces the plastic sheet 50 from the upper side of stage 10'. Therefore, the holes 12 that were provided on stage 10 are not provided on stage 10'.

[0341] (Pick and Place Machine) Figure 26 shows the pick and place process using a pick and place machine in the fourth embodiment.

[0342] As shown in Figure 26(a), the pick-and-place machine 20' holds individual pieces of the thermal recording body 70 on its upper surface by suction or the like. The pick-and-place machine 20' is the same as the pick-and-place machine 20 shown in Figure 22, but inverted vertically (z-direction reversed). Its configuration is the same as that of the pick-and-place machine 20, so redundant explanation will be avoided.

[0343] Figure 27 is a perspective view showing a partial configuration example of a roll of thermal recording material arranged in a pick-and-place machine in the second embodiment.

[0344] As mentioned above, the pick-and-place machine 20' is an inverted version of the pick-and-place machine 20 (inverted in the z-direction). Therefore, when the thermal recording element 70 is placed in the pick-and-place machine 20', its orientation is also inverted compared to when it is placed in the pick-and-place machine 20.

[0345] The thermal recording element 70 shown in Figure 27 is inverted vertically compared to the thermal recording element 70 shown in Figure 23.

[0346] The pick-and-place machine 20' is also transported by the robot arm 5 to the position of the through-hole 61 in the xy plane. When the center of the upper surface 23 of the pick-and-place machine 20' is directly below the center of the through-hole 15, the robot arm 5 rises (moves in the +z direction) and places the individual pieces of the thermal recording body 70 through the through-hole 15 into the through-hole 61 of the plastic sheet 60 placed on the stage 10'.

[0347] Accordingly, as shown in Figure 25(Sb2), the welding machine 30' descends in the -z direction, and as shown in Figure 25(Sb3), the heater tip 33 presses the pressure receiving section 22 of the pick-and-place machine 20' while sandwiching the individual pieces of the plastic sheet 50 and the thermal recording body 70 between them.

[0348] (Welding machine) The welding machine 30' is installed on the upper side (+z side) of the stage 10'. The welding machine 30', like the welding machine 30, can also be realized by employing various welding methods. Then, as shown in Figure 25 (Sb4), a fixed sheet stack 80 can be manufactured.

[0349] In this embodiment, as in the third embodiment, the arrangement of the individual pieces of the thermal recording body 70 and their fixing to the plastic sheet 50 can be performed simultaneously, thereby achieving the same effects as in the third embodiment.

[0350] (Modification 1) As described above, the manufacturing method and manufacturing apparatus according to the first and second embodiments can produce high-quality fixed sheet stacks at low cost and with high production efficiency by simultaneously arranging the thermal recording body and fixing it to the plastic sheet.

[0351] In Modification 1, to further improve productivity, a multi-panel stage is applied to simultaneously carry out the manufacturing process for multiple fixed sheet stacks.

[0352] Figure 28 is a perspective view showing an example of a multi-panel stage applied in the manufacturing apparatus of Modification Example 1.

[0353] Figure 28(a) shows the stage 10 shown in Figure 2(Sa1), and Figures 28(b) and 28(c) show the multi-panel stages 10A and 10B, which are 3x3 times the size of the stage 10.

[0354] In Figures 28(b) and 28(c), the area 16 shown by the dashed line corresponds to the size of the stage 10 shown in Figure 2(Sa1). For the sake of simplicity, only one area 16 is shown in both Figures 28(b) and 28(c), but both the multi-panel stages 10A and 10B contain nine areas 16 arranged in a 3x3 grid.

[0355] In the multi-panel mounting stage 10A shown in Figure 28(b), each region 16 is equipped with positioning pins 11 at its corners. Therefore, the multi-panel mounting stage 10A can simultaneously stack nine sets of plastic sheets 50, 60 of the same size as the stage 10.

[0356] On the other hand, in the multi-panel mounting stage 10B shown in Figure 28(c), the positioning pins 11 are not provided in each region 16, but rather on the outermost periphery of the multi-panel mounting stage 10B. Therefore, the multi-panel mounting stage 10B can stack large 3x3 size plastic sheets 50, 60 of the stage 10.

[0357] Accordingly, nine pick-and-place machines 20 are provided above the multi-panel stages 10A and 10B, and nine welding machines 30 are provided below the multi-panel stages 10A and 10B, each paired with one of the nine pick-and-place machines 20. Each pair performs pick-and-place and welding simultaneously, enabling simultaneous welding at nine locations.

[0358] On the other hand, even if there are not nine pairs of pick-and-place machines 20 and welding machines 30, but only three pairs, nine welding locations can be achieved by having the three pairs perform pick-and-place and welding simultaneously three times. Even in this case, nine welding locations can be achieved in a shorter time than if there were only one pair of pick-and-place machines 20 and welding machines 30.

[0359] Even when the number of pick-and-place machines 20 and welding machines 30 is small, equipment modifications such as increasing the speed of the movement of the stage 10 on the xy plane by the XY positioner 4, increasing the speed of the vertical movement of the heater tip 33 by the welding machine 30, and attaching the local heating head 32 to the robot arm 5 to enable welding at any location make it possible to manufacture a fixed sheet stack with nine heat-sensitive recording elements 70 fixed in a shorter time than generating nine fixed sheet stacks using the stage 10.

[0360] Thus, the manufacturing apparatus of modified example 1 can be implemented in various configurations to suit the required productivity.

[0361] The number of areas 16 placed on the multi-panel stages 10A and 10B is not limited to 3x3, but can be any other size. Similarly, the number of pick-and-place machines 20 and welding machines 30 can also be any number. The operation of the pick-and-place machines 20 and welding machines 30 can also be any method, such as moving up and down on one axis or moving in three dimensions.

[0362] Furthermore, while Modification 1 described the multi-panel stages 10A and 10B corresponding to the stage 10 applied in the third embodiment, the multi-panel stage corresponding to the stage 10' of the fourth embodiment can also be applied.

[0363] (Modification 2) As described above, the manufacturing apparatus 1A according to the third and fourth embodiments, which can improve the productivity of the fixed sheet stack, can be fully automated or implemented in a hybrid manner in which only the main steps are automated and the other steps are performed by humans.

[0364] For example, the placement of plastic sheets 50 and 60 onto stages 10 and 10', and the removal of the completed fixed sheet stack 80 from stages 10 and 10' are performed by an operator, while the pick-and-place operation by the pick-and-place machine 20 and the welding operation by the welding machine 30 are performed simultaneously by automation.

[0365] This hybrid approach allows for lower initial capital investment compared to fully automated systems. Furthermore, it enables flexible operation through human intervention, facilitating immediate responses to abnormalities and necessary flow changes, and facilitating the handling of high-mix, low-volume production. Specific examples of manufacturing equipment realized through this hybrid approach are described below.

[0366] (Manual placement of plastic sheets) The manufacturing apparatus of the modified example 2 is equipped with a camera, AI, etc., in addition to the configuration shown in Figure 19, and is also equipped with an operation button that receives instructions from the operator to proceed to the next step in the process.

[0367] In manufacturing a fixed sheet stack using the manufacturing apparatus of this embodiment 3, an operator takes plastic sheets 50 and 60 from the stacked plastic sheets 50 and 60 supplied, and sets them in the designated position by aligning them with the positioning pins 11 on the stages 10 and 10'.

[0368] After setting up, the worker activates the manufacturing equipment.

[0369] In response, the manufacturing equipment uses cameras, AI, etc., to determine whether the plastic sheets 50 and 60 are correctly set, and also to determine whether safety is ensured. If it determines that the plastic sheets 50 and 60 are not correctly set, or that safety is not ensured, it stops operating.

[0370] (Pick-and-place and welding by multi-axis robot through automation) The manufacturing apparatus of Example 3 is further equipped with a multi-axis robot arm 5. The number of axes can be 6 to 4.

[0371] In this manufacturing apparatus, the robot arm 5 picks up individual pieces of the thermal recording element 70, which are then picked up by the suction section 21 of the pick-and-place machine 20, 20' and placed in the through-hole 61 of the plastic sheet 60.

[0372] The manufacturing apparatus uses an XY positioner 4 to adjust the position of the stages 10, 10' so that the individual pieces of the placed thermal recording body 70 are directly above or directly below the local heating head 32, particularly the heater chip 33.

[0373] The XY positioner 4, for example, uses a ball screw to control the position of stages 10 and 10'. Stages 10 and 10' may also be equipped with safety devices. These safety devices can be area sensors around the stages or surveillance cameras.

[0374] After the positions of the stages 10, 10' or local heating heads are adjusted, the manufacturing apparatus uses the welding machines 30, 30' to weld the plastic sheets 50 to the individual pieces of the thermal recording body 70. The heating time, welding temperature, heating hold time, and cooling time for welding are set according to the materials of the thermal recording body 70 and the plastic sheets 50, and after welding, the manufacturing apparatus may perform a quality check of the welding using a camera.

[0375] An operator may remove the fixed sheet stack 80. At that time, a visual inspection can also be performed simultaneously. This can prevent the generation of defective products. Fixed sheet stacks 80 that are deemed good products may be placed on a conveying system such as a belt conveyor.

[0376] The manufacturing equipment may be equipped with a safety device that detects people in the surrounding area, determines the level of danger, and stops the equipment if the danger level is deemed high. Detection can be performed using cameras, proximity sensors, and drive motor loads. Danger can be determined by AI or judgment logic. This enables collaboration with workers.

[0377] As described above, the manufacturing apparatus 1A according to the third and fourth embodiments can be fully automated or implemented in a hybrid manner, where only the main steps are automated and the other steps are performed by human labor, for example, as shown in Modification 2.

[0378] (Modification 3) Modification 3 describes various configurations of the welding machine 30.

[0379] Figure 29 is a schematic diagram of the manufacturing apparatus 1 according to the first embodiment.

[0380] As described above, the manufacturing apparatus 1 includes a pick-and-place machine 20 / operator display 5, an XY positioner 4, and a welding machine 30, all controlled by a welding controller 3.

[0381] Figure 30 is a block diagram showing various schematic configurations of a welding machine.

[0382] Figure 30(a) is a block diagram showing the schematic configuration of a welding machine 30 of the type that uses a heater tip, as described in the embodiment. In this type of welding machine 30, a power supply 31 supplies power to a local heating head 32, and the local heating head 32 performs welding with the heater tip 33 facing the mounting sheet.

[0383] Figure 30(b) is a block diagram showing the schematic configuration of a welding machine 30A to which a laser welding machine is applied. This type of welding machine 30A is equipped with a laser emission port 36 instead of a heater tip 33, and a power supply 31 supplies power to a local heating head 32, and the mounting sheet is welded by the laser emitted from the laser emission port 36 of the local heating head 32. In this case, the local heating head 32 can weld the mounting sheet without contact.

[0384] Both welding machines 30 and 30A are capable of high-precision welding, making them suitable for welding thermal recording bodies 70, and they can also be applied to welding plastic sheets.

[0385] Figure 30(c) is a block diagram showing the schematic configuration of an ultrasonic welding machine 30B. This type of welding machine 30B uses an oscillator 37 instead of a power supply 31 and is equipped with a horn 38 instead of a heater tip 33. The oscillator 37 supplies high-frequency energy to a local heating head 32, and the mounting sheet is welded by ultrasonic waves output from the horn 38 of the local heating head 32. In this case, the local heating head 32 comes into contact with the mounting sheet to perform the welding.

[0386] Figure 30(d) is a block diagram showing the schematic configuration of a heating and welding machine 30C in which a metal heater head 39 is applied instead of a heater tip 33. In the welding machine 30C, the power supply 31 supplies power to the local heating head 32, and the local heating head 32 performs welding while the metal heater head 39 is in contact with the mounting sheet.

[0387] Both welding machines 30B and 30C are capable of high-speed welding and are suitable for welding plastic sheets together, but they are not very suitable for welding the thermal recording element 70.

[0388] Figure 31 is a block diagram showing an example configuration of an XY positioner.

[0389] The XY positioner 4 includes a driver 4a, an XY stage 4b, and a robot arm 5. In the case of a laser welding machine 30A, the XY positioner 4 further includes a galvanometer mirror.

[0390] Although the best mode for carrying out the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to this configuration. Within the scope of the invented technical idea of ​​the claims, those skilled in the art will be able to conceive of various modifications and alterations, and it will be understood that such modifications and alterations also fall within the technical scope of the present invention.

[0391] 1 Manufacturing equipment 1A Manufacturing equipment 2 Control device 3 Welding controller 4 XY positioner 4a Driver 4b XY stage 5 Robot arm 5a Operator display 10 Stage 10' Stage 10A Stage 10B Stage 11 Positioning pin 12 Hole 13 Suction hole 14 Suction hole 15 Through port 16 Area 20 20' Pick and place machine 21 Suction part 22 Pressure receiving part 23 Bottom surface, top surface 30, 30A-30C 30' Welding machine 31 Power supply 32 Local heating head 33 Heater tip 34 Thermocouple 35 Actuator 36 Laser emitter 37 Oscillator 38 Horn 39 Metal heater head 40 Fixed sheet stack 50, 51, 52, 56 Plastic sheet 57 Hole 58 Hole 60 Plastic sheet 61 Through-hole 62 Hole 70 Thermal recording element 71 Leuco layer 72 Polycarbonate layer 74 Welding mark 75 Welding mark 76 Welding mark 77 Welding mark 80 Primary immobilization sheet stack 85 Additional immobilization sheet stack 90 Secondary immobilization sheet stack 100 Color development layer 102 Photothermal conversion material 103 Chromatograph 104 Leuco dye a Heating start signal b Heating stop completion signal c Head movement signal d Head movement completion signal e Positioning signal f Movement completion signal g Heating current h Thermocouple voltage

Claims

1. A laminate characterized by being made by laminating individual pieces of thermal recording material having welding marks on the corners and / or edges with a plastic sheet.

2. The laminate according to claim 1, characterized in that the welding marks are watermarks.

3. The laminate according to claim 2, characterized in that the watermark is one of the following or a combination of a coat of arms, a national flag, a symbol, a number, text, a code, a signature, a floral pattern.

4. The laminate according to claim 2, characterized in that the watermark is identifiable by visual inspection or camera.

5. The laminate according to claim 4, characterized in that the plastic sheet has infrared absorbing ink printed on it.

6. A method for manufacturing a fixed sheet stack, comprising: an arrangement step of placing an adhesive sheet and a mounting sheet facing each other to form a facing sheet stack; and a welding sequence of welding anchor spots on the facing sheet stack, wherein the anchor spots on the facing sheet stack are at least two locations; the adhesive sheet is a thermal recording body or a plastic sheet; the mounting sheet is a plastic sheet; and the welding sequence includes a heating step of locally heating the anchor spots while the mounting sheet and the adhesive sheet are in direct contact, or while the mounting sheet is in contact with one side of the intermediate layer and the adhesive sheet is in contact with the other side of the intermediate layer, characterized in that the adhesive sheet and the mounting sheet are welded together at the anchor spots.

7. The manufacturing method according to claim 6, characterized in that the thermal recording body has a thermoplastic resin layer on its outermost surface, and any layer in the thermal recording body has heat insulating properties.

8. The manufacturing method according to claim 7, characterized in that the thermoplastic resin layer has heat insulating properties.

9. The manufacturing method according to claim 6, characterized in that the welding sequence is repeated until all of the anchor spots on the facing sheet stack are welded.

10. The manufacturing method according to claim 6, characterized in that the heating step includes heating with a heater tip.

11. The manufacturing method according to claim 10, characterized in that the contact surface of the heater tip, viewed from a direction perpendicular to the thickness direction of the mounting sheet, has curvature.

12. The manufacturing method according to claim 7, characterized in that the heating step involves irradiating the anchor spot with a laser to locally heat the anchor spot.

13. The manufacturing method according to claim 12, characterized in that the laser is an infrared laser and the thermoplastic resin layer is infrared absorbing.

14. The manufacturing method according to claim 12, characterized in that the laser is an infrared laser and the plastic sheet has infrared absorbing ink printed on it.

15. The process includes: an arrangement step of placing an adhesive sheet and a mounting sheet facing each other to form a facing sheet stack; a positioning step of placing a heater chip on an anchor spot on the facing sheet stack; a pressurizing step of applying pressure to the mounting sheet towards the adhesive sheet using the heater chip after the positioning step; a heating step of starting to heat the heater chip while maintaining the pressurized state, raising the heater chip to a predetermined welding temperature, and after the temperature of the heater chip reaches the welding temperature, maintaining the temperature of the heater chip above the welding temperature for a predetermined heating holding time or longer; a cooling step of cooling the heater chip while maintaining the pressurized state after the heating step; after a predetermined cooling time has elapsed, releasing the pressure on the mounting sheet by the heater chip and ending the pressurizing step; and, if there are unwelded anchor spots on the facing sheet stack, repeating the steps from the positioning step to the heating step; and the anchor spots on the facing sheet stack are at least two locations. A manufacturing method characterized in that, if there are no unwelded anchor spots on the facing sheet stack and the number of welded sheets is a predetermined number, the process is terminated; otherwise, the fixed sheet stack fixed in the placement step to the heating step is used as a new adhesive sheet, a new mounting sheet is prepared to be welded to the new adhesive sheet, the new adhesive sheet and the new mounting sheet are placed facing each other to form a new facing sheet stack, and the process is repeated from the placement step to the iteration to produce a fixed sheet stack with a predetermined number of welded sheets.

16. The manufacturing method according to claim 15, characterized in that the adhesive sheet is a thermal recording material or a plastic sheet, and the mounting sheet is a plastic sheet.

17. The manufacturing method according to claim 16, characterized in that the adhesive sheet comprises a plastic sheet with holes and a thermal recording element placed in the holes.

18. The manufacturing method according to claim 15, characterized in that when the product area to be used for the product is cut from the fixed sheet stack, the pressurized area is outside the product area.

19. The manufacturing method according to claim 15, characterized in that, when the product area to be used for the product is cut along the cutting line from the fixed sheet stack, the anchor spot is on the cutting line.

20. The manufacturing method according to claim 16, characterized in that the thermal recording material has welding marks.

21. The manufacturing method according to claim 20, characterized in that the contact surface of the heater chip, viewed from a direction perpendicular to the thickness direction of the mounting sheet, has curvature.

22. The manufacturing method according to claim 15, characterized in that the time required for the temperature of the heater tip to rise to the welding temperature after the start of heating of the heater tip is shorter than the heating and holding time.

23. A fixed sheet stack comprising multiple sheets stacked on top of each other, characterized in that each sheet is welded to an opposing sheet, and there are at least two anchor spots where the sheets are welded.

24. The fixed sheet stack according to claim 23, characterized in that the plurality of sheets include a sheet made of a plastic sheet and a sheet made of a thermal recording body to which the plastic sheet is welded.

25. The fixed sheet stack according to claim 24, characterized in that the thermal recording material has welding marks on the anchor spot.

26. A manufacturing apparatus for manufacturing a fixed sheet stack, comprising: a stage on which a mount sheet is placed; a pick-and-place machine that descends from above the stage, aligns and places an adhesive sheet on the mount sheet, and holds it therein; and a local heating head provided below the stage for welding the mount sheet to the adhesive sheet, wherein the stage is made of glass, or the stage has a hole or window for welding the mount sheet to the adhesive sheet, and the local heating head locally heats the mount sheet from below the stage while the adhesive sheet is held on the mount sheet by the pick-and-place machine, with the mount sheet and the adhesive sheet sandwiched together, thereby welding the mount sheet to the adhesive sheet and manufacturing the fixed sheet stack.

27. The manufacturing apparatus according to claim 26, further comprising a robotic arm for transporting the pick-and-place machine to the position where the descent begins.

28. The manufacturing apparatus according to claim 26 or 27, wherein the pick-and-place machine is provided on its bottom surface with an adsorption section for adsorbing the adhesive sheet and a pressure receiving section that receives pressure from the local heating head during local heating.

29. The manufacturing apparatus according to claim 26, characterized in that the stage is provided with positioning pins for positioning the mounting sheet at a specific location.

30. The manufacturing apparatus according to claim 26, wherein the local heating head constitutes a pulse heat unit comprising a pulse heat power supply and the local heating head heated by the pulse heat power supply, and while the adhesive sheet is held on the mounting sheet by the pick-and-place machine, the local heating head presses the mounting sheet from below the stage through the hole, and heats the mounting sheet while sandwiching it together with the pick-and-place machine.

31. The manufacturing apparatus according to claim 30, wherein the pulse heat unit comprises a plurality of local heating heads, the number of holes provided in the stage corresponds to the number of local heating heads, and when heating the mounting sheet, each of the plurality of local heating heads heats the mounting sheet by passing through one of the holes, thereby simultaneously heating multiple locations.

32. A manufacturing apparatus comprising: a stage on which mounting sheets are arranged; a pick-and-place machine provided below the stage for holding adhesive sheets; and a local heating head provided above the stage for welding the mounting sheets to the adhesive sheets, wherein the stage is provided with a through-hole through which the pick-and-place machine holding the adhesive sheets can pass; the pick-and-place machine rises from below the stage through the through-hole, thereby bringing the held adhesive sheet and the mounting sheet into contact; and the local heating head locally heats the mounting sheet while the adhesive sheet and the mounting sheet are facing each other, thereby welding the mounting sheet to the adhesive sheet and manufacturing a fixed sheet stack.

33. The manufacturing apparatus according to claim 32, further comprising a robotic arm for transporting the pick-and-place machine to the position where the upward movement begins.

34. The manufacturing apparatus according to claim 32 or 33, wherein the pick-and-place machine is provided on its upper surface with an adsorption section for adsorbing the adhesive sheet and a pressure receiving section that receives pressure from the local heating head during local heating.

35. The manufacturing apparatus according to claim 32, characterized in that the stage is provided with positioning pins for positioning the position in which the mounting sheet is placed.

36. The manufacturing apparatus according to claim 32, wherein the local heating head constitutes a pulse heat unit comprising a pulse heat power supply and the local heating head heated by the pulse heat power supply, and the local heating head presses the mounted sheet of the opposing sheet stack from above the stage, and locally heats the mounted sheet while sandwiching it together with the pick-and-place machine.

37. The manufacturing apparatus according to claim 32, wherein the local heating head has a laser head, and a laser-transmitting plate presses the mounting sheet from above the stage, and the mounting sheet and the adhesive sheet are sandwiched together with the pick-and-place machine, and the mounting sheet is locally heated by laser irradiation from the laser head.

38. The manufacturing apparatus according to claim 29, characterized in that the stage includes a plurality of regions, each of which a mounting sheet is arranged, and each of the plurality of regions is provided with the positioning pin and the hole.

39. The manufacturing apparatus according to claim 29, characterized in that the mounting sheet is a large mounting sheet capable of simultaneously manufacturing multiple fixed sheet stacks, and the stage is provided with the holes in each region where each of the multiple fixed sheet stacks is manufactured.

40. The manufacturing apparatus according to claim 38 or 39, characterized by comprising a number of pick-and-place machines and local heating heads equal to the number of regions.

41. The manufacturing apparatus according to claim 38 or 39, comprising fewer pick-and-place machines and local heating heads than the number of regions, wherein each pick-and-place machine is provided with a robotic arm for transporting it to the position where it begins to descend, and each local heating head is provided with a robotic arm for transporting it to the position where it begins to rise.

42. The manufacturing apparatus according to claim 35, characterized in that the stage includes a plurality of regions, each of which a mounting sheet is arranged, and each of the plurality of regions is provided with the positioning pin and the through-hole.

43. The manufacturing apparatus according to claim 35, wherein the mounting sheet is a mounting sheet capable of simultaneously manufacturing multiple fixed sheet stacks, and the stage is provided with the through-holes for each region in which each of the multiple fixed sheet stacks is manufactured.

44. The manufacturing apparatus according to claim 42 or 43, characterized by comprising a number of pick-and-place machines and local heating heads equal to the number of regions.

45. The manufacturing apparatus according to claim 42 or 43, comprising fewer pick-and-place machines and local heating heads than the number of regions, wherein each pick-and-place machine is provided with a robotic arm for transporting it to the position where upward movement begins, and each local heating head is provided with a robotic arm for transporting it to the position where downward movement begins.

46. ​​A method for manufacturing a fixed sheet stack, comprising: a placement step of placing a mount sheet on a stage; a holding step of a pick-and-place machine descending from above the stage, aligning and placing an adhesive sheet on the mount sheet, and holding it therein; a pressing step during the holding step of a welding machine rising from below the stage and pressing the mount sheet through a hole provided in the stage; and a welding step of locally heating the mount sheet and welding it to the adhesive sheet while the welding machine holds the mount sheet and the adhesive sheet between itself and the pick-and-place machine.

47. A method for manufacturing a fixed sheet stack, comprising: a placement step of arranging a mount sheet on a stage; a holding step of a pick-and-place machine rising from below the stage, passing through a through-hole provided in the stage, and holding the mount sheet facing the adhesive sheet it is holding; a pressing step of a welding machine descending from above the stage during the holding step and pressing the mount sheet; and a welding step of locally heating the mount sheet and welding it to the adhesive sheet while the welding machine is sandwiching the mount sheet and the adhesive sheet between it and the pick-and-place machine.

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