EP1184718A1

EP1184718A1 - Method and apparatus for packing presensitised plates

Info

Publication number: EP1184718A1
Application number: EP00203060A
Authority: EP
Inventors: Lourens Johannes Kniesenburg; Erwin Michael Toet
Original assignee: Fujifilm Manufacturing Europe BV
Current assignee: Fujifilm Manufacturing Europe BV
Priority date: 2000-09-04
Filing date: 2000-09-04
Publication date: 2002-03-06
Anticipated expiration: 2020-09-04
Also published as: DE60031848D1; DE60031848T2; EP1184718B1

Abstract

Method for packaging presensitised plates (40), wherein the plates are positioned between two layers of foil (36,42) wherein said layers of foil are sealed together in front and behind said plates, said layers of foil preferably being stretched in a first direction, whereby said seals lie near said plates, preferably pressed against said plates due to said elastically stretching, wherein said layers of foil are closed at both sides of said plates.

Description

Background of the invention

The invention relates to a method for packaging presensitised plates, in a light tight manner. Such method is known from practice.
In a normally used, well-known method a bundle of presensitised plates is packed in laminated, light tight paper by folding and closing said paper around said bundle, such that the bundle is completely enclosed. The thus formed package is then enclosed within a cardboard wrapping of a standard size. To this end a cardboard blank is formed having a flat back portion on which said package is placed. The back portion is provided with an elevated edge, against which the package is placed with a first side, a second side, perpendicular to said first side extending along a folding line through which the back portion is connected to a side panel. Cardboard spacers are glued to the inside of the package, on the back portion, at least against the side of the package opposite said first side and one against the side opposite said second side. Then the cardboard blank is folded around said packed bundle of plates and closed with conventional means such as tape and glue.
In this known method the paper is used to shield the plates from light. Then the spacers and said two sides of the outer package are used to secure the packed bundle in place within said cardboard box. The cardboard box is used to prevent the plates from mechanical damage and to provide for a standard size package, independent of the actual size of the plates.
This known method has the disadvantage of packaging the plates in laminated paper, which is costly and time consuming, as is said paper itself. The laminated paper is environmentally unfriendly and can be easily damaged. Moreover, this method requires high precision. Furthermore, this method has the disadvantage that the spacers are necessary for securing the plates in a stacked position within said bundle. If the spacers are incorrectly placed or come loose during transport, the bundle of plates can move within the cardboard box whereas the plates can move relative to each other within said stack. Both types of movement can then easily lead to damage to the plates, especially to the presensitised properties. Also the laminated paper can become torn, resulting in loss of light resisting properties, rendering the plates worthless.

Description of the invention

A first object of the present invention is to provide for a method for packaging presensitised plates in which the disadvantages of the known method are prevented, maintaining the advantages thereof.
A second object of the invention is to provide for such method in which the plates can be stacked in a bundle and enclosed, such that the plates will be secured in the bundle without the risk of damage due to movement of the plates relative to each other within said package.
A further object of the invention is to provide for such method which is less time consuming and more economical, wherein placement of the bundle of plates requires less precision.
These and further objects are reached by a method having the features of claim 1.
In a method according to the present invention presensitised plates, preferably in bundles, are packed primarily in foil, between two layers. The foil is protective to the plates and is preferably elastically stretched in at least one direction, between seals on either side of said plates, thereby enclosing said plates and when elastically stretched forcing them together. The latter position results in a secure position of the plates and prevents relative movement thereof. Preferably light tight elastomeric foil is used, shielding the plates from light and thus maintaining the light sensitive properties.
In a preferred embodiment a method according to the present invention, the layers of foil are interconnected on the other sides substantially without stretching said foil in any direction enclosing an angle with said first direction. In packaging bundles of substantially rectangular plates this means that in said first direction, between two opposite sides, the foil is stretched, whereas in a direction perpendicular to said first direction the foil is not stretched. Surprisingly stretching in only one direction has proven to be sufficient in most cases to prevent relative movement of the plates within said bundle. This results in an even easier method for stacking, since stretching has to be obtained in only one direction. Furthermore, a larger freedom of choice of foil is available since also foils can be used which can be elastically stretched in only one direction.
In a further preferred embodiment a method according to the present invention is further characterised by the features of claim 4.
In this embodiment the layers of foil are fed from continuous strips, the plates being placed in between. Seals are formed in front of and behind said plates while the layers are stretched elastically. In the feeding direction of at least the layers a seal is formed between two bundles of plates and then cut, in a direction substantially perpendicular to said feeding direction, such that part of said seal forms a first seal behind the bundle in front (seen in said feeding direction), the other part of said seal forming a seal in front of the next bundle. Thus a continuous method can be obtained. In such embodiment it is further preferred that the foil layers are at least partly fed by applying pressure to said front seal, such that elastically stretching of said layers is obtained. A further seal can then easily be provided behind said bundle.
Preferably foil prepared of PE, PP or blends thereof are used, comprising black pigments, which foil is light tight, can be elastically deformed, are relatively economical and environmentally friendly. Moreover, such foils are readily available and can be used in single layered form. It is preferred that relatively thin foil is used. Surprisingly foils having a thickness of less than 150 micrometer have proven to be sufficient. More preferably even thinner foils are used, especially foils having a thickness of less than 85 micrometers, for example 70 micrometers.
In a further preferred embodiment a method according to the present invention is further characterised by the features of claim 7.
Since the plates are packed in the layers of foil, such that relative movement of plates in a bundle is prevented by said layers, the thus packed bundles can be easily positioned inside an outer box, such as a cardboard box, using glue. Said glue has to be position on only one side of the bundle to prevent movement of the bundle within said box. Preferably glue is applied in at least two patches, stripes or such spaced apart positions, thereby even better preventing movement of the bundle. Friction glue therein has the advantage that the bundle can be taken out easily, substantially without leaving a trace of the glue on the bundle, whereas it secures the position of the plates sufficiently. Glue could obviously also be applied on both sides of the bundle.
The invention further relates to an apparatus for packaging presensitised plates, characterised by features of claim 15.
In an apparatus according to the present invention, which is especially suitable for practising a method according to the present invention, two layers of light tight, preferably elastomeric foil, e.g. polyethylene or polypropylene foil, comprising dark pigments, can be fed using supplying means, whereas presensitised plates can be fed between said two layers, in an insertion direction, between said two layers by feeding means. Furthermore, means are provided for stretching the two layers, at least in a direction substantial parallel to said insertion direction can be provided, as well as means for providing seals in front and behind said plates, seen in said insertion direction. During use the plates are inserted between said layers of foil, between a first seal in front of said plates and a second seal which is formed trailing said plates, such that after release of said foils said two layers enclose the plates, and are if stretched forced against said plates including said seals, as a result of elastic forces within said layers. The layers of foil and seals are thereby brought in full contact with said plates.
The present invention further relates to a package, comprising a bundle of presensitised plates, characterised by the features of claim 19.
In such package the bundle of plates is fully enclosed within light tight foil which is sealed around said bundle. The two layers of foil are thereby elastically stretched, such that they are forced into full contact with at least the outer plates of said bundle, thereby ensuring there position within said package. Surprisingly, it has proven to be unnecessary in most cases to also stretch said layers in a direction perpendicular to the direction between said first seals. A package according to the present invention is very stable, easily handled and obtainable in an economical way, whereas foils can be used which are relatively thin, easy to handle, tear resistant and environmentally friendly, especially in single layer versions, for such foils can be recycled.
Further advantageous embodiments of a method and apparatus according to the present invention are given in the dependent claims.
In further elucidation of the present invention embodiments are shown of methods, apparatus and packages according to the present invention, with reference to the drawings and in comparison to the prior art.
Figure 1 shows an inner package according to the prior art;
figure 2 shows an inner package according to figure 1 in an outer package;
figure 3 shows, schematically in cross section, a side view of an apparatus according to the present invention;
figure 3A shows at an enlarged scale, part of the apparatus according to figure 3;
figure 4 shows in perspective view a package according to the present invention, especially an inner package; and
figure 5 shows in perspective view an outer package for use with an inner package according to figure 4.
In this description corresponding parts have corresponding reference signs. The embodiments given in the accompanying drawings are only given as an example and should not be construed as limiting the scope of the claims.
Figures 1 and 2 show an inner and outer package according to the prior art as described in the introduction to the specification. Figure 1 shows an inner package 1, comprising a stack or bundle of presensitised plates, fully enclosed in laminated paper 2, folded around said stack of plates and closed by a number of strips of adhesive tape 3. In this inner package 1 the laminated paper 2 is in contact with the plates as much as possible.
In figure 2 the inner package 1 is shown, positioned on an open outer package 4, made of cardboard. The outer package 4 is folded from a blank and comprises a back panel 6, on two opposite sides connected to front panels 8 by two sets of parallel folding lines 10 enclosing side panels 12. Along the sides of the back and front panels 6, 8 perpendicular to said folding lines 10 elevated edges 14 are formed by folding inward part of the relevant panel 6, 8. The height H₁ of the inner side of said elevated edge 14 is preferably maximum half the height H₂ of the inner package 1. When the front panels 8 and side panels 12 are folded over approximately 90° along the folding lines 10, relative to the back panel 6, the front panels 8 can be positioned on top of the inner package 1, the elevated edges 14 of the front panels 8 lying on the elevated edges 14 of the back panel 6, thus enclosing said inner package 1. The width W₁ of the front panels 8 is approximately half the width W₂ of the back panel 6.
As can be seen in figure 2, the inner package 1 has a length L₃ and a width W₃ smaller than the width W₂ and length L₁ between the elevated edges 14 of the back panel 6. The size of the inner package 1 is obviously merely defined by the size of the presensitised plates. In order to secure the position of the inner package 1 within the outer package 4, the inner package 1 is positioned against one of the elevated edges 14 on the back panel 6, a side of said inner package 1 lying against a folding line 10. Cardboard spacers 16 are glued onto the back panel 6, one positioned against the inner package 1 to a first side, opposite the elevated edge 14 against which the inner package 1 rests, the other spacer 16 against the side of the inner package 1 opposite said folding line 10 along which the package 1 is positioned. When closed around said inner package 1, the outer package 4 together with the spacers 16 therefore secure the position of the inner package 1 within said outer package 4.
As can be understood from this description this known method of packaging presensitised plates is time consuming, costly and relatively laborious.
In figure 3 schematically an apparatus is shown for packaging presensitised plates, especially bundles or stacks of such plates, according to the present invention, using foil for enclosing said bundle of plates.
An apparatus 20 according to the present invention comprises supply means 22 for supplying two layers of light tight foil, feeding means for feeding presensitised plates, in bundles, between said layers of foil, in a feeding direction R, sealing means 26 for sealing the layers of foil for enclosing said bundle of presensitised plates between said layers of foil and cutting means 28 for cutting an inner package 30 thus formed loose from said layers of foil.
The supply means 22 comprise an upper roller 32 of elastomeric foil comprising black, or at least dark pigment, whereas a second, lower roller 34 is provided, also comprising a roll of such elastomeric foil. From the upper roller 32 a first layer 36 is provided, which is guided around an upper guide means 38 to a substantially horizontal position, forming an upper layer above a bundle of presensitised plates 40. Similarly, a second layer 42 of foil is provided from the lower roller 34, which is guided around guide means 44 to a substantially horizontal position, parallel to the first layer 36, below said bundle of presensitised plates 40. The first and second layer 36, 42 are both continuous. In the situation as shown in figure 3, in front of the bundle of presensitised plates 40, that is in figure 3 at the left side of said bundle 40, a first seal 46 is provided, which has been made and cut by the sealing means 26 and cutting means 28 respectively. The bundles of presensitised plates 40 are fed over the feeding means 24, for example a transport belt, against said first seal 46 which at that time was positioned between an upper and lower knife 28A, 28B of the cutting means. In figure 3 a second bundle of presensitised plates 40 is shown in broken lines pushed by the feeding means 24. When feeding said bundle of presensitised plates 40 from said position in broken lines to the position as shown in full lines in figure 3, the first seal 46 is pushed forward in the feeding direction R, in figure 3 to the left, such that the trailing end 48 is pushed passed the sealing means 26 and cutting means 28. During this movement the first layer 36 and second layer 42 are elastically stretched in the direction of transportation R, which constitutes a first direction. This elastically stretching can for example be obtained by breaking means (not shown) preventing the upper and lower rollers 32, 34 from unwinding the first and second layer 36, 42 respectively with the same speed as the speed of said bundle of presensitised plates 40.
When said trailing end 48 has passed the sealing means 26, a clamp 53 fixes the stretched part from the first seal 46 to the clamp. Next the stretch at the feeding part of the foils is relieved. Then the sealing means are closed against the first and second layer 36, 42 and are heated, such as to form two heat seals, connecting said first and second layer 36, 42. The thus formed seals behind the trail 48 of said bundle of presensitised plates 40 are then separated by the cutting means 28, in a direction perpendicular to said feeding direction R, such that behind said trailing end 48 a second, double seal 50 is formed, schematically shown in figure 3, in broken lines, whereas a first seal 46 is at the same time formed in front of a next bundle of presensitised plates, as shown in broken lines in figure 3, to the right of said sealing and cutting means 26, 28. In figure 3 said second seal 50 is spaced apart from said trailing end 48. In figure 3A the first and second bundle of presensitised plates 40 are partly shown, at an enlarged scale, together with the second seal 50 behind the trailing end 48 of a first bundle 40 and the first seal 46 in front of a next bundle 40A, trailing said first bundle. As can be understood from figure 3A, which shows the cut seals, the layers 36 and 42 enclosing the first bundle 40 will under the influence of the elastic tension due to said stretching, retake as far as possible their original form as soon as the clamp 53 is withdrawn. This means that the layers 36, 42 will be forced against the bundle of plates 40, at least on the upper and lower side and on both ends, seen in the first direction R, said direction of feeding. As indicated before, the trailing bundle 40A can then be forced forward in said first direction R, passing the sealing means 26. In the embodiment shown (figure 4), on either side of the bundle 40, parallel to said direction of feeding R, two further seals 52 are provided, further enclosing said bundle 40. These further seals 52 are provided at a slight distance of said bundle 40 or at least without stretching said layers 36, 42 between said further seals 52. These further seals 52 are therefore relatively loose, sloppy seals. Such further seals 52 can be provided easily, for example by seal means comprising heated rollers or the like.
Figure 4 shows an inner package 30 enclosing a bundle of presensitised plates, comprising an upper layer 36 and a lower layer 42 of light tight foil, stretched in said first feeding direction R, between a first seal 46 an a second seal 50, whereas said further seals 52 are shown on either side of said inner package. This inner package 30 can easily be manipulated and for example be placed in an outer package such as shown in figure 2. However, preferably an outer package is used as is described with reference to figure 2, wherein the use of spacers 16 has been abandoned. In this embodiment the outer package 4, made of for example corrugated cardboard, comprises two lanes of friction glue on the back panel 6, on which the inner package (not shown) can be easily positioned. Thus the inner package 30 is stuck to the back panel 6 of the outer package 4 in any desired position, for example a position as shown in figure 2, using the commonly known inner package 1. In an embodiment according to the present invention the bundle of plates 40 is easily held in place by the slightly elastically deformed layers 36, 42. Preferably, the further seals 52 are folded under the second layer 42 before pressing said inner package 30 to the glue 54 on the back panel, thereby even better enclosing said plates 40. By using lanes of friction glue 54 the inner package 30 is prevented from movement within a closed outer package 4 without the necessity of said spacers, which makes it easier to fit the inner package 30. Moreover, such package needs less material and is therefore economical.
Surprisingly, in a method and package according to the present invention relatively thin layers 36, 42 of foil can be used, for example polyethylene foil having a thickness of less than 150 micrometer. Black PE foil of both 85 micrometers and 100 micrometers thickness have been used with satisfactory light tightness and tensile strength. The tensile strength of the plastic foils are not only determined by its thickness but also by the polymer density of the foil. The density is preferably larger than 0.94 for properly stretching around the edges of the presensitised plates without ruptures of the plastic foil. Low foil thickness seems to reach a limit around 70 micrometer, which is feasible if the density of the foil is about 0.96 g/cc. When the density is dropped below 0.94, ruptures in the foils occur easily.
In an alternative embodiment, which is not specifically shown, said first layer 36 and said second layer 42 are folded from a single strip of foil by folding said strip of foil along a folding line extending parallel to the feeding direction R. The bundle of presensitised plates 40 is introduced and sealed between said two layers 36, 42 in a similar manner as described. Such method has the advantage that only one further seal 52 has to be provided. The present invention is not limited to the embodiments as shown and described with reference to the drawings. Many further embodiments should be considered to fall within the scope of the invention as presented in the claim.
For example, if desirable, the layers of foil can also be stretched elastically in a direction perpendicular to the first direction, said direction of feeding, as long as the type of foil used enables such elastically stretching, whereas the layers of foil can also enclose said plates without being stretched, maintaining the advantage of easy packaging in a light tight manner. Obviously the further seals can be provided for before, during as well as after forming the first and second seals 46, 50. The seals can be provided for by other means, for example glue. If desired, also single presensitised plates could be packaged with a method according to the present invention. In fact, any number of presensitised plates could be packaged accordingly. Also friction glue could be provided for in other patterns, such as dots, more of less lanes or the like. It should be noted that a number of the advantages mentioned could also be obtained using friction glue with the known inner package. Other materials can be used for the foil. Moreover, the feeding direction could be chosen differently, for example vertically, whereas other means for transportation of the layers of foil and/or the bundles of presensitised plates can be used, for example gravity.
These and similar embodiments should be considered to fall within the scope of the invention as presented in the pending claims.

Claims

Method for packaging presensitised plates, wherein the plates are positioned between two layers of foil, wherein said layers of foil are sealed together in front and behind said plates, said layers of foil preferably being stretched in a first direction, whereby said seals lie near said plates, preferably pressed against said plates due to said elastically stretching, wherein said layers of foil are closed at both sides of said plates.
Method according to claim 1, wherein said layers of foil are connected relatively loose at the further sides, said layers of foil substantially not being stretched in a direction perpendicular to the first direction, between said further sides.
Method according to claim 1 or 2, wherein the layers of foil are closed at the sides after sealing the foil in front of and behind said plates and releasing said layers, seen in said first direction.
Method according to any one of claims 1 - 3, wherein said layers of foil are fed in a feeding direction, preferably substantially parallel to said first direction from continuous strips of foil, wherein a seal is formed behind said plates, which seal is cut in a direction perpendicular to said feeding direction, such that a first part of said seal forms a seal behind the plates in front of said seal, a second part of said seal forming a second seal in front of plates which are positioned behind said second part of said seal.
Method according to claim 4, wherein said seal is preferably a double seal, of which the parts can be separated by cutting the area between the first and the second part in a direction perpendicular to said feeding direction, such that a first part of said double seal forms a seal behind the plates in front of said seal, a second part of said double seal forming a second seal in front of plates which are positioned behind said second part of said double seal.
Method according to any one of the preceding claims, wherein the plates are inserted between said two layers of foil, in an insertion direction, thereby feeding the layers of foil in the feeding direction by pressure applied to the seal preceding seen in the insertion direction and stretching said layers.
Method according to any one of the preceding claims, wherein an elastomeric foil is used containing dark, preferably black pigments.
Method according to any one of the preceding claims, wherein the elastomeric foil is a foil with a density larger than approximately 0.94 g/cc.
Method according to any one of the preceding claims, wherein the plates, packed in said preferably light tight layers of foil, are positioned in a box, preferably made of cardboard, wherein the foil is on at least one side glued to said box.
Method according to claim 8, wherein said foil is glued to said box using friction glue.
Method according to claim 8 or 9, wherein at least two areas of glue are used, distanced from each other.
Method according to any one of the preceding claims, wherein said foil has a thickness of less than 150 micrometer.
Method according to claim 12, wherein said foil has a thickness of less than 100 micrometer.
Method according to claim 13, wherein said foil has a thickness of less than 85 micrometer, preferably between 70 and 85 micrometers.
Apparatus for packaging presensitised plates, comprising:

means for supplying two layers of light tight foil;

means for feeding photo sensitive plates between said two layers, in an insertion direction; and

means for forming seals of the layers of foil in front of and behind said plates, seen in the direction of insertion, wherein preferably means are provided for at least elastically stretching said two layers of foil in the insertion direction, such that at least after release of said elastically stretched foil said seals are in full contact with the plates.
Apparatus according to claim 15, wherein the means for supplying said two layers of foil comprises two spaced apart foil-supply means and guide means for supporting and guiding said layers to a position parallel to each other, wherein further means are provided for sealing said layers of foil to each other on either side of the plates, seen in the direction of insertion, preferably at a distance from said plates.
Apparatus according to claim 15, wherein the means for supplying said two layers of foil comprises foil supply means for supplying a film of foil in a folded position, such that said film is folded over about 180 degrees along a folding line extending parallel to a direction of feeding of said supply means and guide means for supporting and guiding said folded film such that two parts of said folded film on either side of said folding line form said two layers, in a position parallel to each other.
Apparatus according to any one of claims 15 - 17, wherein means are provided for cutting each seal made in front of or behind said plates, along a cutting line perpendicular to said direction of insertion, such that on both sides of said cutting line a closed part of said seal is provided.
Package, comprising a bundle of photo sensitive plates, wherein said bundle is enclosed within two layers of light tight foil preferably elastomeric foil, which package is substantially rectangular, wherein on two opposite first sides of said bundle a first seal is formed, connecting said layers of foil, said layers being elastically stretched between said first seals, wherein said layers of foil are connected on the remaining opposite second sides of the bundle, substantially perpendicular to the first sides, substantially without stretching said layers between said second sides.