Apparatus for and method of producing resin laminated cards

A cassette which retains a plurality of stacked resin sheets is loaded on a retaining member of a driving device. A plurality of press-heating stations and a number of cooling stations which is smaller than the number of press-heating stations are disposed around the driving device, and the retaining member is sequentially sent to each of the stations by means of the driving device. In each press-heating station, each of the resin sheets in the cassette retained by the retaining member is thermowelded, and the press-heated resin sheets are cooled in the cooling station. The cassette comprises a cassette body for accommodating a plurality of stacked resin sheets, and a pressing plate brought into contact with the stacked resin sheets so as to press them by means of a resilient member such as a coned disk spring. Thus, the resin sheets are moved from one press-heating station to another while being maintained in a pressed state.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus for producing resin laminated 
cards by thermowelding a plurality of resin sheets. 
2. Description of the Related Art 
Resin laminated cards are produced in such a manner that printed matter 
which carries a picture, characters, etc. is clamped between a plurality 
of resin sheets, and these resin sheets are thermowelded together to seal 
the printed matter. This technique is now applied to ID cards, driver's 
licenses and the like. 
A typical conventional apparatus for producing such resin laminated cards 
is arranged such that a plurality of resin sheets which have printed 
matter clamped therebetween are thermowelded using press means and a 
heater. 
In this conventional apparatus, a jig for clamping a plurality of resin 
sheets is inserted into a press machine where the resin sheets are 
thermowelded by means of a pressing force applied by the press machine and 
heating applied by the heater, and after the press machine has been 
released, the jig is taken out, and another jig which clamps new resin 
sheets is inserted into the machine. 
Therefore, the conventional apparatus takes a disadvantageously long time 
to produce a resin laminated card, and it has heretofore been impossible 
to obtain a multiplicity of resin laminated cards, such as ID cards, 
within a short period of time. 
SUMMARY OF THE INVENTION 
In view of the above-described circumstances, it is a primary object of the 
present invention to provide a method which enables a multiplicity of 
resin laminated cards to be produced within a short period of time, 
together with an apparatus which is suitably employed to carry out the 
novel method. 
To this end, according to one aspect of the present invention, there is 
provided a resin laminated card producing apparatus which comprises: a 
cassette retaining a plurality of resin sheets in a stacked state; a 
plurality of press-heating stations for thermowelding each of the resin 
sheets within the cassette; a cooling station for cooling the press-heated 
resin sheets within the cassette; and driving means for sequentially 
sending the cassette to each of the stations. 
It is generally necessary to heat a material for a resin laminated card 
under pressure for about four minutes, whereas it only takes two minutes 
to cool the heated material. Therefore, if a cassette which retains a 
plurality of resin sheets in a stacked state is sequentially sent to a 
press-heating station and a cooling station, it is possible to obtain an 
increased number of resin laminated cards within a reduced period of time 
as compared with the conventional apparatus. However, in this case, the 
cassette must be at rest in each station for four minutes which is needed 
for a press-heating operation. On the other hand, the apparatus according 
to the present invention has a plurality of press-heating stations; 
therefore, if, for example, two press-heating stations are provided and a 
press-heating operation is carried out for two minutes at each station, 
resin sheets can be subjected to press-heating process for a total of four 
minutes, and yet the time required for the resin sheets to stay at each 
station can be reduced to two minutes. 
For this purpose, it is preferable to arrange the cassette such that a 
predetermined pressing force can be maintained while the cassette is moved 
from one press-heating station to another so that the pressed state formed 
by the first press-heating station is not canceled. 
The driving means is adapted to retain the cassette in such a manner that 
it is movable in the direction in which resin sheets accommodated therein 
are pressed, whereby each press-heating station is allowed to press the 
resin sheets at any desired position in the pressing dierection, so that 
the manufacture of the apparatus is facilitated. 
If the above-described stations are disposed around the driving means, the 
cassette can be smoothly circulated through the stations, and this enables 
an improvement in efficiency. 
Each press-heating station may be arranged such as to transmit pressing 
force through coned disk springs. Coned disk springs are suitable for 
accurately transmitting a relatively large pressing force. The 
interposition of the coned disk springs facilitates the control of 
transmission of a relatively large pressing force. 
According to another aspect of the present invention, there is provided a 
cassette which may be employed in the above-described resin laminated card 
producing apparatus, the cassette comprising: a cassette body for 
accommodating the above-described plurality of stacked resin sheets; and a 
pressing plate secured to the cassette body to clamp the resin sheets 
between the same and the cassette body. 
This cassette is preferably further provided with a resilient member which 
presses the pressing plate against the stacked resin sheets. 
The cassette body has a hole for accommodating the resin sheets, and the 
distance between the bottom of this accommodating hole and the pressing 
portion of the pressing plate is set such as to be substantially equal to 
the total thickness of the resin sheets after they have been subjected to 
thermowelding process. 
According to still another aspect of the present invention, there is 
provided a resin laminated card producing method which comprises the steps 
of: stacking a cassette with a plurality of resin sheets in such a manner 
that the sheets are retained by the cassette; sequentially sending this 
cassette to a plurality of press-heating stations so as to thermoweld each 
of the resin sheets; and moving the cassette one press-heating station to 
another while maintaining a pressed state of the cassette.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIGS. 1 and 2 show in combination a resin laminated card producing 
apparatus 10. This apparatus 10 has a machine frame 12, and a driving 
means 14 is disposed on the substantially central portion of the frame 12. 
A cassette loading and unloading section 16, a first press-heating station 
18, a second press-heating station 20 and a cooling station 22 are 
disposed around the driving means 14 at equal spacings. 
A cassette 24 is loaded on the driving means 14 at the cassette loading and 
unloading section 16. The cassette 24 is heated under pressure in the 
first and second press-heating stations 18, 20, cooled in the cooling 
station 22, and then unloaded from the driving means 14 at the cassette 
loading and unloading section 16. 
Referring next to FIGS. 3 and 4, the cassette 24 has a cassette body 26 
which is formed from a thick-walled metal material, preferably aluminum. 
An opening 28 having a rectangular cross-section extends through the 
central portion of the body 26, and an accommodating hole 30 having a 
larger area than that of the opening 28 is formed in the body 26 such as 
to extend from the surface thereof, the hole 30 having a depth D from the 
surface. 
A plurality of metal sheets 32 are accommodated in the accommodating hole 
30. A resin sheet 34 is clamped between each pair of adjacent metal sheets 
32. Each resin sheet 34 is folded as at 34A and 34B, and two ends of the 
folded sheet 34 are brought into contact with each other to define 
practically two resin sheets, between which printed matter which carries a 
photograph, characters, etc. is inserted in advance. In consequence, when 
this resin sheet 34 is heated under pressure in the first and second 
press-heating stations 18 and 20, the obverse and reverse layers of the 
resin sheet 34 are thermowelded together to seal the printed matter 
therein. 
Although in this embodiment the resin sheet 34 is folded along the portions 
34A and 34B to define practically two resin sheets, two separate resin 
sheets may also be employed in such a manner that they are laid one upon 
the other and disposed between a pair of adjacent metal sheets 32. 
A pressing plate 36 is laid on the cassette body 26 and rigidly secured to 
the latter by means of screws 38. The plate 36 has a rectangular opening 
40 in opposing relation to the rectangular opening 28 provided in the body 
26. A rib 42 projects from the peripheral edge of the opening 40 in such a 
manner that the rib 42 is fitted into the accommodating hole 30. 
The distance by which the rib 42 projects from the pressing plate 36 is set 
such as to be E. Accordingly, when the pressing plate 36 is tightly 
fastened to the cassette body 26 by means of the screws 38, the clearance 
defined by the accommodating hole 30 and the rectangular opening 40 is 
(D-E). It is therefore preferable to determine the dimension (D-E) so that 
it equals the sum of the total thickness of a plurality of metal sheets 32 
and the total thickness of finished products defined by a plurality of 
resin sheets 34 after they have been press-heated and the thickness 
thereof has consequently been reduced. 
However, before being press-heated, each resin sheet 34 has a larger 
thickness than that of the sheet 34 when finished as a product. For this 
reason, even when the pressing plate 36 is tightly fastened to the 
cassette body 26 by means of the screws 38 before the press-heating 
process, a slight gap is undesirably produced between the pressing plate 
36 and the cassette body 26 after the pressheating process. 
In view of these circumstances, the screws 38 are adapted to continuously 
press a plurality of resin sheets 34 with a predetermined pressure through 
the pressing plate 36 even while the cassette 24 is being moved from the 
first press-heating station 18 to the second press-heating station 20. 
The driving means 14 has a rotating shaft 44 which extends vertically and 
which is rotatably supported by the machine frame 12, and a frame member 
46 is rigidly secured to the shaft 44. As shown in FIG. 2, the frame 
member 46 has a rectangular planar shape, and vertical walls 47 extend 
vertically from the four sides, respectively, of the frame member 46 in 
such a manner that the walls 47 can face the above-described stations. 
A pair of guide blocks 48 are rigidly secured to the outer periphery of 
each of the vertical walls 47 of the frame member 46, the guide blocks 48 
being spaced apart from each other at a predetermined distance. These 
guide blocks 48 respectively have vertical grooves 50 which face each 
other. Two side portions of a lifting plate 52 are respectively 
accommodated in these grooves 50 so that the lifting plate 52 is movable 
vertically. As shown in FIG. 5, the downward movement of the lifting plate 
52 is limited by a stopper 54 which is rigidly secured to the frame member 
46 so as to abut against the lower end of the plate 52. A fork 56 projects 
horizontally from the lower end portion of the lifting plate 52. Two 
projecting pieces which define the fork 56 are respectively fitted into 
parallel grooves 58 which are formed in two outer side portions of the 
cassette body 26. Thus, in the cassette loading and unloading section 16, 
the cassette 24 can be loaded onto and unloaded from the fork 56 using 
these grooves 58 as shown in FIG. 1. In addition, the cassette 24 is 
vertically movably supported by the guide blocks 48 through the fork 56 
and hence the lifting plate 52. 
As shown in FIG. 2, the rotating shaft 44 is operatively connected to a 
motor 60 secured to the frame 12 through a timing chain 62 stretched 
therebetween, whereby the shaft 44 is rotated and then stopped when the 
forks 56 face predetermined stations, respectively. For this purpose, a 
disk 64 is, as shown in FIG. 1, secured to the frame member 46 so as to 
rotate together with it. The disk 64 has circular grooves 66 formed in the 
outer peripheral portion thereof at a predetermined regular spacing. Thus, 
when one of the grooves 66 receives a detecting member 68 of a limit 
switch, the motor 60 is suspended, and the forks 56 are thereby positioned 
so as to face the respective stations. 
As shown in FIG. 1, the first press-heating station 18 includes a pair of 
side plates 70 which stand on the machine frame 12, and the respective 
upper ends of these side plates 70 are connected by a top plate 72. A 
motor 74 and a reduction gear 76 are rigidly secured to the side plates 
70. 
Referring to FIG. 5, a gear 80 is rigidly secured to an output shaft 78 of 
the reduction gear 76. This gear 80 is meshed with a gear 84 which is 
rigidly secured to the upper end portion of a threaded shaft 82 shown in 
FIG. 6. 
The shaft 82 has the upper and lower end portions thereof rotatably 
supported through bearings 86 so that the axis of the shaft 82 extends 
vertically. The bearing 86 which supports the upper end portion of the 
shaft 82 is rigidly secured to the top plate 72, while the bearing 86 
which supports the lower end portion of the shaft 82 is rigidly secured to 
a bracket 88 which projects from the frame 12. 
A right-hand external thread 90 is cut in the lower end portion of the 
intermediate portion of the shaft 82, and a left-hand external thread 92 
in the upper end portion thereof, these threads 90 and 92 being in thread 
engagement with internal threads formed in lower and upper lifting blocks 
94 and 96, respectively. The blocks 94 and 96 are movably supported on a 
pair of guide posts 98 through bearings 100, respectively, the guide posts 
98 being disposed parallel to the shaft 82. The respective upper ends of 
the guide posts 98 are rigidly secured to the top plate 72, and the lower 
ends thereof to the bracket 88. 
Accordingly, the lower and upper lifting blocks 94 and 96 are moved toward 
and away from each other in equal amounts in response to the rotation of 
the motor 74. 
Arms 102 and 104 respectively project from the blocks 94 and 96 toward the 
driving means 14. A pressing block 106 projects from the arm 102 toward 
the arm 104. 
A spring seat 108 is rigidly secured to the arm 104, and a shaft 110 
extends through the axial center of the spring seat 108. A pressing block 
112 is rigidly secured to the lower end of the shaft 110 in one unit. The 
upper end portion of the shaft 110 projects from the upper side of the 
spring seat 108, and a nut 114 is screwed onto this projecting end potion, 
thereby preventing the shaft 110 from coming off the spring seat 108. 
A combination of a plurality of coned disc springs 116 is disposed between 
the pressing block 112 and the spring seat 108. Accordingly, the pressing 
blocks 106 and 112 are movable toward and away from each other in unison 
with the movements of the lower and upper lifting blocks 94 and 96. 
When the pressing blocks 106 and 112 are moved toward each other, they are 
respectively inserted into the rectangular openings 28 and 40 in the 
cassette 24 which is positioned in the first press-heating station 18, 
thereby applying a relatively large pressing force to a plurality of metal 
sheets 32 as shown in FIG. 8. Heaters 117 are disposed in the pressing 
blocks 106 and 112 so that it is possible to heat the resin sheets 34 to a 
desired temperature through the metal sheets 32 while applying pressure 
thereto. 
Although the pressing block 106 is rigidly secured to the arm 102, the 
pressing block 112 is supported by the arm 104 through the coned disk 
springs 116. Therefore, during the pressing operation the block 112 is 
movable relative to the arm 104 under a predetermined load. This relative 
movement is detected in such a manner that a striker 120 which is rigidly 
secured to the block 112 presses a limit switch 118 rigidly secured to the 
arm 104. 
In this case, the amount of displacement of the coned disk springs 116 
occurring when a required pressing force is generated has been obtained in 
advance by calibration through a load cell disposed between the pressing 
blocks 106 and 112. In an actual operation, when the set amount of 
displacement is reached, this state is detected by the limit switch 118, 
whereby it is possible to reliably apply a desired pressing force to the 
resin sheets 34. 
When the pressing force is applied to the resin sheets 34 in the cassette 
24, the driving means 14 need not maintain the cassette 24 at a retained 
position in the vertical direction with specially high accuracy since the 
cassette 24 is vertically movable relative to the fixed guide blocks 48 
through the fork 56 and the lifting plate 52. More specifically, it is 
only necessary to arrange the mechanism such that, when the pressing 
blocks 106 and 112 clamp the metal sheets 32 therebetween as shown in FIG. 
7, the cassette 24 is slightly moved upward together with the fork 56 with 
respect to the frame member 46. 
Since the arrangement and operation of the second press-heating station 20 
are similar to those of the first press-heating station 18, description 
thereof is omitted. 
Referring to FIGS. 1, 8 and 9, the cooling station 22 also has a vertically 
moving mechanism similar to that in the first press-heating station 18. 
More specifically, the rotation of a motor 74 is transmitted to a threaded 
shaft 82 through a reduction gear 76 and a pair of gears 80 and 84, 
thereby allowing power and upper lifting blocks 94 and 96 to move toward 
and away from each other while being guided by guide posts 98. 
Further, pressing blocks 122 and 124 are similarly disposed on arms 102 and 
104 which project from the lower and upper lifting blocks 94 and 96, 
respectively. Accordingly, these pressing blocks 122 and 124 produce a 
pressing force through coned disc springs 116 in a way similar to that in 
the case of the first press-heating station 18. However, the biasing force 
of the springs 116 is set such as to be relatively small because the 
pressing force required in the cooling station 22 is smaller than that in 
the first and second press-heating stations 18 and 20. 
In addition, the pressing blocks 122 and 124 in the cooling station 22 are 
made hollow as shown in FIG. 9, and cooling air inlet and outlet openings 
126 and 128 are provided at two ends, respectively, of each of the blocks 
122 and 124. The inlet openings 126 are adapted to be able to face ducts 
132, respectively, which extend from a fan 130 secured to the frame 12. 
Thus, when the pressing blocks 122 and 124 are pressing the cassette 24, 
they are cooled by the cooling air, thus cooling the resin sheets 34 
through the metal sheets 32. 
In order to efficiently apply this cooling air to the surfaces of the 
pressing blocks 122 and 124 which are in contact with the cassette 24, 
guide plates 134 are respectiely secured to the blocks 122 and 124 so as 
to direct the cooling air to portions of the blocks 122 and 124 which are 
in contact with the cassette 24. 
The cassete 24 accommodates a plurality of metal sheets 32 and resin sheets 
34, each resin sheet being disposed between each pair of adjacent metal 
sheets 32, in the space defined between the cassette body 26 and the 
pressing plate 36, and the plate 36 is rigidly secured to the body 26 by 
means of the screws 38. In the cassette loading and unloading section 16, 
this cassette 24 is loaded onto the fork 24 using the grooves 58 formed in 
two outer side portions of the cassette 24. 
Then, the driving means 14 causes the frame member 46 to rotate a 1/4 turn 
by means of the driving force derived from the motor 60, so that the 
cassette 24 mounted on the frame member 46 faces the first press-heating 
station 18. 
In the first press-heating station 18, the lower and upper lifting blocks 
94 and 96 are moved toward each other by means of the driving force from 
the motor 74 and inserted into the rectangular openings 28 and 40, 
respectively, in the cassette 24 to clamp the pluraility of metal sheets 
32 with a relatively large force as shown in FIG. 7. At the same time, an 
electric current is supplied to the heaters 11 within the blocks 106 and 
112, so that each of the resin sheets 34 clamped between the metal sheets 
32 is heated under pressure and thereby thermowelded. 
In this case, a desired pressing force is reliably applied through the 
control effected by the limit switch 118 which is actuated when the coned 
disk springs 116 are displaced by a preset amount. If there were no coned 
disk springs 116, it would be necessary to finely control the amount of 
rotation of the threaded shaft 82 in order to obtain a desired pressing 
force, which is impractical. 
In the first press-heating station 18, heating under pressure is carried 
out only a half of the time required for the resin sheets 34 to be 
completely thermowelded. Thereafter, the motor 60 is rotated again so that 
the driving means 14 moves the cassette 24 from the first press-heating 
station 18 to the second press-heating station 20. During this movement 
also, the cassette 24 is maintained in a state wherein the cassette body 
26 and the pressing plate 36 is producing a predetermined pressure, and it 
is therefore possible to minimize the amount by which the resin sheets 34 
are pressed and heated in the second press-heating station 20. 
In the second press-heating station 20, the resin sheets 34 in the cassette 
24 are simultaneously pressed and heated by the pressing blocks 106 and 
112 in a manner similar to that in the first press-heating station 18. The 
amounts by which the resin sheets 34 are pressed and heated may be equal 
to those in the case of the first press-heating station 18. 
When the press-heating operation in the second press-heating station 20 is 
completed, the obverse and reverse layers of each resin sheet 34 are 
completely thermowelded together, and the printed matter which has been 
clamped therebetween is thereby reliably sealed. 
The resin sheets 34 thus thermowelded need to be cooled in order to ensure 
the sealing structure. For this reason, the driving means 14 causes the 
cassette 24 to make another 1/4 turn so that it is sent to the cooling 
station 22. In this cooling station 22, the pressing blocks 122 and 124 
which are in contact with the metal sheets 32 cool the resin sheets 34 
with the cooling air sent from the fan 130, thereby allowing each of the 
thermowelded resin sheets 34 to have the printed matter reliably sealed 
therein. 
Then, the driving means 14 further makes a 1/4 turn to return the cassette 
24 retaining the thermowelded resin sheets 34 to the cassette loading and 
unloading section 16. In consequence, the operator can unload the cassette 
24 and load a new cassette 24 which has not yet been subjected to a 
thermowelding operation. 
Although in the above description of the operation a single cassette 24 is 
loaded on the driving means 14 due to the convenience of explanation, it 
is possible to load a new cassette 24 on each fork 56 which is newly 
disposed at the cassette loading and unloading section 16 every time the 
loaded cassette 24 rotates a 1/4 turn so that each step in the 
thermowelding operation is constantly executed at each station. Thus, it 
is possible to obtain resin laminated cards at high efficiency. 
Accordingly, the press-heating operation is shared between the first and 
second press-heating stations 18 and 20 so as to shorten the resin 
laminated card producing cycle of the apparatus 10. 
It should be noted that each of the thermowelded resin sheets 34 is taken 
out of the cassette loading and unloading section 16 and then sent to 
another process where the resin sheet 34 has the periphery thereof trimmed 
to become a finished product. Although in this embodiment loading and 
unloading of the cassette 24 at the cassette loading and unloading section 
16 are carried out by a manual operation, the cassette 24 may be 
automatically loaded and unloaded. 
FIGS. 11 and 12 show in combination another example of a cassette which may 
be employed in the present invention. In this cassette, the accommodating 
hole 30 in the cassette body 26A is gradually increased in the inside 
diameter toward the pressing plate 36. The minimum inside diameter of the 
hole 30 is set such as to be equal to the outside diameter of metal sheets 
32 and resin sehets 34 which are to be inserted therein. In addition, the 
pressing plate 36, which is pressed against the cassette body 26A, is 
subjected to the biasing force from coned disk springs 142 which are 
fitted on the screws 38. 
Thus, while the cassette is being moved among a plurality of press-heating 
stations, the clamping force produced between the pressing plate 36 and 
the cassette body 26A is maintained at a constant level by virtue of the 
coned disk springs 142. Accordingly, a clearance defined between the 
pressing plate 36 and the cassette body 26A when the former is completely 
pressed against the latter can be made equal to the sum of the total 
thickness of resin sheets 34 as finished products and the total thickness 
of a plurality of metal sheets 32. 
When a resin sheet 34 is pressed, its thickness is reduced, while its area 
is increased, and the outside diameter thereof is consequently enlarged. 
Therefore, an increase in the outside diameter is accommodated by a 
portion of the accommodating hole 30 which has an increased inside 
diameter. 
As has been described above, the resin laminated card producing apparatus 
according to the present invention comprises: a cassette retaining a 
plurality of resin sheets in a stacked state; a plurality of press-heating 
stations for thermowelding each of the resin sheets within the cassette; a 
cooling station for cooling the press-heated resin sheets within the 
cassette; and driving means for sequentially sending the cassette to each 
of the stations. 
Accordingly, it is advantageously possible to produce a multiplicity of 
resin laminated cards within a short period of time.