PatentDe  


Dokumentenidentifikation EP0814962 30.08.2001
EP-Veröffentlichungsnummer 0814962
Titel VERFAHREN UND VORRICHTUNG ZUM ABZIEHEN VON LAMINATSCHICHTEN, DIE EIN BILD TRAGENDES MEDIUM ENTHALTEN
Anmelder Polaroid Corp., Cambridge, Mass., US
Erfinder RYAN, James F., Marlboro, US;
KNIAZZEH, Alfredo G., Waltham, US
Vertreter PAe Splanemann Reitzner Baronetzky Westendorp, 80469 München
DE-Aktenzeichen 69614098
Vertragsstaaten DE, FR, GB, NL
Sprache des Dokument EN
EP-Anmeldetag 11.03.1996
EP-Aktenzeichen 969103316
WO-Anmeldetag 11.03.1996
PCT-Aktenzeichen US9602570
WO-Veröffentlichungsnummer 9628306
WO-Veröffentlichungsdatum 19.09.1996
EP-Offenlegungsdatum 07.01.1998
EP date of grant 25.07.2001
Veröffentlichungstag im Patentblatt 30.08.2001
IPC-Hauptklasse B41M 7/00
IPC-Nebenklasse B32B 35/00   

Beschreibung[en]
BACKGROUND OF THE INVENTION

In general, the present invention relates to systems and methods for delaminating laminates, and more particularly, to systems and methods for delaminating protective overcoating layers on an image bearing medium in a manner which minimizes the -formation of artifacts in the image bearing medium.

A recent development in the image forming arts employs the use of thermal imaging laminates for achieving high quality, high resolution images, such as for radiological images useful in the medical arts. Examples of such media are described in WO 88/04327; and U.S.Patent No. 5,200,297. More particularly, the noted International Patent Application describes a thermal imaging medium and a process for forming an image. The medium is a laminate in which an image forming layer thereof is a porous or particulate imaging material, preferably, a layer of carbon black that is deposited on a heat-activatable image-forming surface of a first sheet-like element. The image forming layer has an adhesive strength to a first sheet-like element of the laminate that is a function of its exposed state. The first sheet-like element carrying the imaging material is covered with a second sheet-like element that is laminated to the first so that the imaging material is confined between the first and second sheets.

This medium can be imagewise exposed as by laser scanning, whereby exposed portions of the imaging material are firmly attached to the first sheet, and unexposed portions of the imaging material are firmly attached to the second sheet. The result is a first image surface which comprises exposed portions of an image-forming substance that is more firmly attached to the first sheet and a complementary second image surface which comprises non-exposed portions of the image-forming substance carried or transferred thereto.

After imaging in the manner noted, the sheets are then peeled or delaminated with the first sheet carrying exposed imaging material portions, and the second element carrying unexposed portions. As a result of the peeling, a pair of complementary or binary image layers is obtained, either one of which may for reasons of informational content be considered the principal image area. Such image forming materials and processes are capable of producing extremely high quality and high resolution images.

However, there are possibilities for damaging the image layer by physical contact, physical elements or the like. Therefore, it is desirable to protect the image forming layer. One known approach is through the application of a protective overcoating material, e.g. a thin, transparent, but durable layer, such as described in WO 92/09930. Lamination of protective overcoats, such as those described in the cited patent applications, have been accomplished by using a continuous roll, i.e. carrier web, to transfer the durable protective layer to the image carrying sheets. Activation energy is necessary for fusing the durable layer to the imaged sheet at a nip formed by and between a pair of compression rollers.

While such laminating approaches are successful, nevertheless possibilities exist for artifacts, such as pinholes, being formed in the laminated image sheet when the latter is delaminated from the carrier web. Pinholes are considered to be disruptions in the image forming or bearing layer which permit the undesired passage of light therethrough. For instance, pinholes can vary in size from about 10 to 300 µm. During delamination of the imaged sheet, some of the image bearing particles can be physically removed because of being adhered to the release layer of the overcoating material on the carrier web. While pinholes are not necessarily large, their presence can otherwise diminish achievement of the high resolution achievable by the foregoing type of imaging media. As a result of such pinholes of this removal type, the final imaged product may not be commercially acceptable. Accordingly, there is a continuing desire for improving upon known efforts to enhance the protection of the image layer while reducing the formation of undesirable pinholes which might adversely affect image quality.

US-A-4,631,110 discloses an apparatus for delaminating a carrier web from an image bearing medium wherein the laminate is passed through means for advancing the carrier in a first direction past a heated delaminating bar, such that thereafter the carrier web and image bearing medium are advanced in different directions. The apparatus further includes means for controlling the temperature of the delaminating assembly to a temperature range from 30 to 40°C.

SUMMARY OF THE INVENTION

According to the present invention, provision is made for improving upon known methods and systems for reducing pinhole formation in image bearing material on an image carrying medium, for reducing the formation of pinholes in the image bearing layer upon release of the overcoating material during delamination, while minimizing physical distortions to the image bearing medium, such as minimizing fringing of the sheet and/or minimizing curling and rippling of the image bearing medium.

Accordingly, the invention relates to a system and a method for delaminating a carrier web laminate carrying a protective overcoating material after the overcoating material has been laminated onto an image bearing layer carried on an image bearing medium by heat and pressure applying means, as defined in claims 1, 4 and 5, respectively.

Furthermore, the invention relates to a system for protecting an image bearing medium carrying an image bearing layer by a heat softenable protective overcoating material carried on a carrier web laminate therefore, as defined in claim 6, and a process of protecting an image bearing layer on an image carrying medium with a heat softenable overcoating layer, as defined in claim 8.

Preferred embodiments are recited in the dependent claims.

The temperature controlling means may comprise at least a surface on the delaminating member having a thermal heat transfer of coefficient which is effective for controlling heat exchange so as to maintain the temperature within the range.

The temperature controlling means may also comprise means for directing air past the delamination assembly for controlling its temperature, or may include a heating element for actively heating the delaminating assembly.

Other objects and further scope of applicability of the present invention will become apparent when reading the following detailed description thereof when taken in conjunction with the accompanying drawings wherein like parts are represented by like reference numerals throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS

  • Figure 1 is a diagrammatic cross-sectional side elevational view of a web and an image carrying medium prior to lamination;
  • Figure 2 is a diagrammatic cross-sectional side elevational view of the web and the image carrying medium of Figure 1 during lamination;
  • Figure 3 is a diagrammatic cross-sectional side elevational view of a protective overcoat bonded to an image carrying medium in the process of delamination;
  • Figure 4 is a diagrammatic side view of a laminating and delaminating system according to a preferred embodiment of the invention shown in one mode of operation; and,
  • Figure 5 is a diagrammatic side view of another embodiment of the system similar to Figure 4 in which there are shown a blower and heating element for controlling temperature of a delaminating bar.

Detailed Description

In one preferred embodiment, as illustrated in Figs. 1-4, there is provided a laminating sheet 10 comprising a carrier web 11 and in juxtaposed relationship thereto a protective overcoating material 12 adapted to be laminated onto an image forming or bearing layer 14 carried on a substrate 15 of an image bearing sheet or medium 16 for purposes of protecting the latter. The web 11 and its integral protective coating material 12 form a laminating sheet which can be like that described in the last noted patent applications. Essentially, the web 11 forms a support layer for the overcoating materials 12 which overcoating materials comprise an exterior adhesive layer 18, a barrier layer 19, an intermediate durable layer 20, and a release layer 22. The protective overcoat, i.e. a thermal transfer overcoat, is thermally bonded to the image bearing medium 16 including the image bearing layer 14 in a laminating process to be described. Preferably, the release layer would be ,completely removed from the durable layer following lamination. However, in practice, the release layer does not cleanly separate from the durable layer, so that upon delamination of the carrier web some of the porous particles forming the image forming layer 14 are unnecessarily removed therewith. Accordingly, undesirable pinholes or openings can be formed in the image forming layer, thereby permitting light to pass therethrough. These pinholes, although not shown, usually range in shape and size from about 10 to about 300 µm.

Fig. 1 illustrates the laminating sheet 10 disposed in juxtaposed relationship over the image carrying medium 16. In the illustrated embodiment, the image carrying or bearing medium referred to as a keeper includes an image bearing layer 14 which is made of, for example, carbon particles formed on a transparent substrate layer 15 made of, for example, polyester. It will be understood that the image forming medium 16 has had another polyester layer (not shown) and complementary layer (not shown) of carbon particles removed therefrom, the removed particles are referred to as a throwaway layer. In the illustrated embodiments, the thicknesses of the keeper or image forming medium 16 and the noted throwaway layer can be about 0,013 to 0,25 mm (0.5 to 10 mil) and 0,013 to 0,18 mm (0.5 to 7 mil); respectively. For a more detailed description of this type of thermal imaging media, reference is made to the aforementioned WO 88/04327. Examples and methods of obtaining an image carrying medium 16 may be had from the description in U.S. Pat. No. 5,155,003; and, U.S. Pat. No. 5,200,297; which descriptions are incorporated herein by reference. While these examples all relate to imaging media wherein the image forming or bearing surfaces are porous or the particulate image bearing surfaces are developed by laminar separation, use of the present invention is not limited to developed thermal imaging media, but rather, can also be used advantageously for the protection of images prepared by resort to other known imaging methods including, but not limited to, those prepared by thermal dye transfer, ink jet, and laser ablation transfer methods.

Reference is made back again to the laminating sheet 10, which in this embodiment is in the form of a continuous web having a width generally wider than the image bearing or carrying medium 16 for ensuring complete lamination coverage of the image carrying surface. The web 11 can be formed of any material, such as a filled polyester film base, which supports the thermal transfer overcoating material. Some characteristics of the web 11 are that it has no subcoats. The web widths can vary from about 560 to 1600 mm (22 inches to 63 inches) with roll lengths being 6100 to 12200 m (20,000 to 40,000 linear feet). Of course, other dimensions for the laminating sheet can be employed given the particular medium being laminated. Film roughness can be approximately 0.2µm RMS. Unrestrained heat shrinkage values are about 4% in both the machine and transverse directions when measured at 150°C for 30 min. The thickness can be about 0.023 mm (0.92 mil), but other thickness dimensions can be used consistent with the principles of the present invention. The web 11 may be formed from any material, besides the noted polyester material, so long as it can withstand the conditions which are required to laminate the protective overcoat material 12 to the image carrying medium 16. If desired, the web 11 may be treated with a subcoat or other surface treatment, as well-known, to those skilled in the coating art, to control its surface characteristics, for example, increase or decrease the adhesion of the durable layer 20 to the web 24 by means of the release layer 22. The web 11 should be sufficiently coherent and adherent to the durable layer 20 to permit displacement of both the web 11 and part of the release layer 22, away from the protected laminated image carrying medium including removal of those portions of the laminating sheet 10 which extend beyond the periphery of the medium 16.

With reference to the thermal overcoat material, the durable layer 20 may be formed from any material (such as a cured acrylic polymer or a polymethacrylate) which confers the desired properties for protecting the image. For example, the aforenoted WO 92/09930 describes an embodiment wherein the durable layer 20 is coated as a discontinuous layer from a latex which clears during lamination to produce a clear durable layer. As described, the durable layer is comprised 80% by weight acrylic polymer, 10% by weight polyethylene/paraffin wax, and 10% by weight aqueous-based polyamide binder, and was prepared by mixing the polymer and wax lattices, adding the binder, then adding a silicone surfactant. In general, it is preferred that the overcoating material 12, when laminated over the binary image bearing layer, not have a thickness greater than about 30 µm, since thicker overcoating layers may, in some cases, cause problems in viewing the image due to optical effects within the overcoating material 12. Desirably, the thickness of the durable layer 20 does not exceed 10 µm, and, more desirably, this thickness is in the range of 3 to 6 µm. The durable layer 10 should of course be abrasive and chemically resistant to materials with which it is likely to come into contact, including the materials which may be used to clean the protected laminated image carrying medium. Although the exact materials which may contact the image will vary with the intended uses of the protected laminated image carrying medium, in general it is desirable that the material for the durable layer 20 should be resistant to and substantially unchanged by any materials with which it may come into contact, such as water, isopropanol and petroleum distillates.

It will be appreciated that the protection of the image carrying medium 16 conferred by the protective overcoat is improved with increased lubricity. Therefore, at least one of a wax, a solid silicone and silicone surfactant is, preferably, included in the durable layer 20 to increase the lubricity of this layer. Also, the release layer 22 can be composed of a material having high lubricity.

Referring back to the release layer 22, it may break unevenly so that part of the release layer having a discontinuous thickness remains with a discard or throwaway layer or sheet 36 and another part of the release layer 22 remains attached to the durable layer 20 on the keeper substrate sheet or medium 16. As noted, however, pinholes in the image forming layer, which are referred to as the removal type, are caused when particulate pieces or chunks (not shown) of the carbon of the image forming layer 14 tend to adhere to and go with the part of the release layer 22 remaining with the throwaway layer 36; see Fig. 3. It will be seen that the throwaway layer 36 will include the entire laminating sheet when it is not laminated to the image bearing medium 16.

Now referring to the adhesive layer 18 of the coating material 12, it is disposed on the surface of the durable layer 20 remote from the web 11. During lamination, the durable layer is adhered to the image layer 14 by means of the adhesive layer 18. The use of an adhesive layer 18 is desirable to achieve strong adhesion between the durable layer 20 and the image carrying medium 16. Various types of adhesive may be used to form the adhesive layer 18. For example, the adhesive layer 18 might be formed from a thermoplastic adhesive having a glass transition temperature in the range of about 85°C (185°F), in which case bondability is effected by the conductive heating of the adhesive layer above its glass transition temperature. An example of a suitable adhesive layer 18 is designated X95-180. The barrier layer 19 is preferred to be an aqueous barrier coating which performs solvent resistance functions. It can be a PVDC material, such as Daran ® 158. A laminating sheet 10 which comprises the above laminar constructions is available from Polaroid Corporation, Cambridge, Massachusetts, USA.

In the laminating system of Fig. 4, the laminating sheet 10 is juxtaposed to the image carrying medium 16 and both are fed together at a suitable rate, such as about 13 mm (.5 inches) per second to a laminating unit. Both the sheet 10 and the image bearing medium 16 travel through a compression nip 28 formed between a heated roller assembly 30 which is about 90 mm (3.5 inches) in diameter and is actively heated by a heating device (not shown), and a cold roller assembly 32 which is also approximately 90 mm (3.5 inches) in diameter, and is actively cooled by a cooling device (not shown). As will be noted hereinafter, the sheet 10 and the medium 16 can be prewrapped onto an angular portion of the cold roller assembly 32. A variety of heating devices can be used to heat the heated roller assembly 30. For instance, the heating device can take the form of an interior resistance cartridge controlled by an external thermistor spaced near the top surface of the hot roller. The heated roller assembly 30 is preferably maintained at a temperature of about 166 ± 3°C (320 ±5°F) and the cold roller assembly 32 is, preferably, maintained at a temperature of about 32°C (90°F) or less in order to minimize ripple and curl in the protected laminated image carrying medium 34; as described in greater detail in the last noted applications. Both the hot roller assembly 30 and the cold roller assembly 32 should be constructed from conductive materials, such as aluminum, and at least one of the rollers should have a compliant elastomeric layer to evenly distribute a nip loading of about 363 kg (800 lb.), Referring back to the cold roller assembly 32, any commercially available cooling unit can be used to actively cool the temperatures which are desired. The cold roller assembly 32 can be cooled either internally, such as by circulating cool air or a liquid coolant through the interior of the roller, or externally, such as by fanning cooled air over the cold roller surface. The structure of the cold roller assembly 32 can be designed to maximize the cooling effect of the cooling unit. For instance, a cold roller cooled by air flow could be designed as a hollow roller with internal fins.

As the laminating sheet 10 and the image carrying medium 16 are fed through the nip 28, a bonded image carrying medium 34 is formed due to the adhesive layer 18 softening, molding to, and adhering to the image carrying medium under a compressive force for a time sufficient to promote adhesion of it and the barrier layer, the durable layer and portions of the release layer.

After passing through the nip 28, the bonded sheet and image carrying medium 16, designated jointly as the bonded image carrying medium 34, are postwrapped along the cold roller assembly 32 for an arcuate distance defined by the angle &thetas;1, where &thetas;1 is ideally about 20 degrees. However, this angle can vary for the reasons noted in the above noted application for eliminating some types of laminating artifacts, such as longitudinal curl and ripples, in the protected laminated image carrying medium 34. The purposes for postwrapping the laminated or bonded image carrying 34 are noted in the last noted application. Basically, the first is to counter a curl tendency when the sheet 10 is prewrapped along the hot roller assembly 30; the second is extracting heat from the bonded image carrying medium 34 along the cold roller assembly 32 for eliminating ripples in the protective overcoat; a third is to prevent thermal expansion from buckling the sheet 10 and thereby imparting ripples thereto; and, the fourth is to maintain a bond between the sheet 10 and the cold roller assembly 32 during a time in which the web temperature is high enough to otherwise distort the web dimensions, compromising registration quality. The degree of postwrap angles at which the sheet and the medium 16 contact the lower cold roller do not form part of the present invention and will not be discussed herein in further detail. Also, the sheet 10 and the image bearing medium 16 are prewrapped and the prewrap angles can also vary.

For purposes of understanding curl, it is defined as any curvature of the protected laminated image carrying medium 34 away from the plane of its major surface area. Curl can occur in either the longitudinal direction which is the direction of feeding of the sheets, or in the transverse direction which is perpendicular to the longitudinal direction. Rippling which generally occurs in the transverse direction, i.e. the direction perpendicular to the feed direction of the web is defined as oscillating elevations of the protected laminated image carrying medium above or below the plane of the major surface area of the protected laminated image carrying medium.

After postwrapping the bonded web and image carrying medium 34 throughout the arcuate distance of &thetas;1, the throwaway layer 36, consisting of the web 11 and a part of the release layer 22, is separated from the protected laminated image carrying medium 34 by a delaminating assembly which in the preferred embodiment is in the form of an elongate delaminating bar 50 extending generally parallel to the laminating roller assemblies. In this regard, the throwaway layer 36 is wound onto take-up roller 52 (as shown in Figure 4) with the assistance of the tension supplied by a pair of pull rolls 53. In the process, the throwaway layer 36 is brought against a delaminating surface 54 defined by the outside surface of the bar 50 with sufficient tension so as to effect separation or delamination of the throwaway layer 36 from the laminated image carrying medium 34. As noted, the protected laminated image carrying medium 34 includes the image bearing substrate 15, the image forming layer 14, the adhesive layer 18, the durable layer 20, and part of the release layer 22. The image bearing medium 34 is pulled under constant tension in a direction different from the throwaway layer by a pair of eject rolls 55.

As noted the sheet 10 can have a variety of widths and can be a continuous 81.3 mm (32 inch) wide member which spans between an idle supply roller 56 and a driven take-up roller 52. The width of the web 10 is set to ensure its registration with the width of the image carrying medium 16. For instance, the image carrying medium 16 can vary in widths which vary from about 203 to 762 mm (eight inches to about 30 inches).

In accordance with the present invention it has been determined that for reducing the formation of pinholes in the image forming layer 14 during delamination at the delaminating bar 50, the heated temperature of the delaminating bar be-controlled to be within a predetermined range which has been effective to reduce pinhole formations. The type of pinholes reduced are those of the removal type which are formed by the removal of carbon particles from the image forming layer 14 during delamination of the carrier web 11 and the release layer 22 from the laminated medium 34. It is believed that the significant reduction of the size of the pinholes, by as much as 90% when compared to other approaches in delaminating without the temperature being controlled as indicated, is due to the fact that the controlled heated temperature affects the release forces of the release layer 22, such that they are more uniform and thus, the adherence forces on the carbon by the adhesives on the medium 16 are overcome. As a result, the carbon is not readily pulled away with the throwaway layer 36. It has been found that the temperature range which is essential for effecting the pinhole size reduction for the materials above is in a range of about 51 to 71°C (125 to 160°F). If the temperatures are too high there might be a problem with fringing. Fringing occurs when a clean break between the protected laminated image carrying medium 34 and the throwaway layer 36 is not realized, so that pieces or strips of durable layer 20 and adhesive layer 18 remain attached in a stringy form to the edge of the protected laminated image carrying medium 34. In the illustrated embodiment, the delaminating bar 50 can be an elongated and hollow piece of anodized aluminum which extends generally parallel to the roller assemblies. It has been determined that such an aluminum bar has a thermal heat transfer coefficient which is effective for 5 controlling heat exchange of the medium and layer 34 and 36; respectively so as to maintain the temperature within the noted temperature range. Of course, other materials besides aluminum can be used.

In the illustrated embodiment of Fig. 5, the delaminating bar 50 can have its temperature controlled so as to be actively heated by an electrical heating element 60 which is disposed therein. Temperature sensors, not shown, can regulate the temperature provided by the heating element so that the delaminating bar 50 remains in the desired temperature range for effecting the desired pinhole reduction. Also, depicted in Fig. 5, is a blower unit 70 which in this embodiment can be a fan which will be operated to blow air passed the delaminating bar 50 for controlling the temperature thereof. The blower unit need not be used in conjunction with heater for effecting the desired temperature control although it is contemplated that such an arrangement is possible. Of course, appropriate temperature sensors, not shown, can be oppressively connected to the blower for controlling the latter.


Anspruch[de]
  1. System zum Delaminieren eines Trägerbahnlaminats, das ein schützendes Überzugsmaterial trägt, nachdem das Überzugsmaterial auf eine auf einem bildtragenden Medium angeordnete bildtragende Schicht, unter Anwendung von Mitteln zur Ausübung von Hitze und Druck laminiert wurde, enthaltend: eine Delaminierungseinrichtung; Mittel zum Vorwärtsbewegen der Trägerbahn in einer ersten Richtung gegen die Laminierungseinrichtung und zum Vorwärtsbewegen der Folie in einer Richtung, die sich von der der Trägerbahn unterscheidet, um die Delaminierung zu bewirken; und Mittel zum Einstellen der Temperatur der Folie und der Bahn in einen Bereich von etwa 51 bis 71°C (125 bis 160°F).
  2. System nach Anspruch 1, worin die Mittel zum Einstellen der Temperatur Mittel zum aktiven Erhitzen und zum Halten der Delaminierungseinrichtung innerhalb des genannten Bereichs aufweisen.
  3. System nach Anspruch 1, worin die Mittel zum Erhitzen mindestens ein Heizelement in der Delaminierungseinrichtung zum aktiven Erhitzen der Delaminierungseinrichtung auf eine Temperatur innerhalb des genannten Bereichs aufweisen.
  4. Verfahren zum Delaminieren eines Trägerbahnlaminats, das ein schützendes Überzugsmaterial trägt, nachdem das Überzugsmaterial auf eine auf einem bildtragenden Medium angeordnete bildtragende Schicht unter Anwendung von Mitteln zum Aufbringen von Hitze und Druck laminiert wurde; welches folgende Schritte umfasst: Biegen der Trägerbahn gegen eine Delaminierungseinrichtung und Transport der Bahn in eine erste Richtung; Vorwärtsbewegen des bildtragenden Mediums in einer Richtung, die sich von der ersten Richtung unterscheidet, wenn das Medium vorwärts bewegt wird, um die Delaminierung zu bewirken; und Einstellen der Temperatur der Delaminierungseinrichtung auf einen Bereich von etwa 51 bis 71°C (125 bis 160°F).
  5. Verfahren zur Verminderung der Bildung von Nadellöchern in einer bildtragenden Schicht auf einem bildtragenden Medium, das von einer Trägerbahn delaminiert wird, welche ein schützendes Überzugsmaterial trägt, welches folgende Schritte umfasst: Delaminieren eines Teils des Überzugsmaterials von einem bildtragenden Medium, indem die Bahn in eine Richtung, die sich von der Richtung der Vorwärtsbewegung des bildtragenden Mediums unterscheidet, gegen eine Delaminierungseinrichtung bewegt wird, um eine Delaminierung der Trägerbahn von dem Medium an einem Delaminierungspunkt zu bewirken; und Einstellen der Temperatur auf einen Bereich von etwa 51 bis 71°C (125 bis 160°F).
  6. System zum Schützen eines bildtragenden Mediums, welches eine bildtragende Schicht trägt, durch ein in der Hitze erweichbares auf einem Trägerbahnmaterial angeordneten schützendes Überzugsmaterial, enthaltend: eine Heisswalzeneinrichtung, die bei einer ersten vorbestimmten Temperatur wirksam ist, die ausreicht, um mindestens einen Teil des schützenden Überzugsmaterials zu erweichen; eine Kaltwalzeneinrichtung, die bei einer zweiten vorbestimmten Temperatur wirksam ist, die niedriger ist als die erste vorbestimmte Temperatur, wobei die Kaltwalzeneinrichtung und die Heisswalzeneinrichtung während der Laminierung einen Spalt bilden; ein Bahnlaminiat, das ein durch Hitze erweichbares Überzugsmaterial trägt, das so ausgebildet ist, dass es zwischen den Spalt der Walzeneinrichtungen hindurchgeht, um mit der bildtragenden Schicht in Berührung zu kommen, wobei die Heisswalzeneinrichtung die Bahn berührt und das schützende Überzugsmaterial erweicht und die kalte Walze das bildtragende Medium berührt, so dass sich die erweichte schützende Überzugsschicht auf dem bildtragenden Medium verformt und daran haftet, um ein verbundenes bildtragendes Medium zu bilden; eine stromabwärts von der Heisswalzen- und Kaltwalzeneinrichtung angeordnete Delaminierungseinrichtung, mit der die Bahn in Eingriff kommt, wenn sie sich in einer ersten Richtung vorwärts bewegt; und Mittel zum Einstellen der Temperatur der Delaminierungseinrichtung innerhalb einen Bereich von etwa 51 bis 71°C (125 bis 160°F).
  7. System nach Anspruch 6, worin das Bahnlaminat eine Trägerschicht, eine Trennschicht, eine dauerhafte Schicht und eine Klebstoffschicht enthält; worin der schützende Überzug die Trennschicht, die dauerhafte Schicht und die Klebstoffschicht laminiert; worin die Klebstoffschicht und die bildtragende Schicht miteinander in Berührung kommen, wenn die Bahn und das bildtragende Medium in dem Spalt einander gegenüberliegen, wobei die Trägerschicht, die Heisswalzeneinrichtung am Spalt berührt, die Unterlage die Kaltwalze am Spalt berührt und die Klebstoffschicht am Spalt eine Glasübergangstemperatur erreicht, die auf einer Wärmeübertragung von der Heisswalzeneinrichtung beruht.
  8. Verfahren zum Schützen einer bildtragenden Schicht auf einem bildtragenden Medium mit einer durch Erhitzen erweichbaren Überzugsschicht; welches folgende Schritte umfasst: Aneinanderlegen der schützenden Überzugsschicht und des bildtragenden Mediums;
    • Erhitzen einer Heisswalzeneinrichtung auf eine erste vorbestimmte Temperatur, die ausreicht, um die schützende Überzugsschicht zu erweichen;
    • Abkühlen einer kalten Walze auf eine zweite vorbestimmte Temperatur, die niedriger als die erste vorbestimmte Temperatur ist; Ausbildung eines Spalts zwischen Walzeneinrichtungspaar und Zusammenpressen der Heisswalzen- und der Kaltwalzenanordnung mit einer Kraft, die ausreicht, um eine Haftung zwischen der erweichten schützenden Überzugsschicht und dem bildtragenden Medium zu fördern; und Verbinden der aneinanderliegenden schützenden Überzugsschicht mit dem bildtragenden Medium, um ein verbundenes bildtragendes Medium zu erzeugen, indem die einander liegende schützende Überzugsschicht und das bildtragende Medium durch den Spalt geführt werden, wobei die Bahn die heisse Walze am Spalt berührt und das bildtragende Medium die kalte Walze am Spalt berüht;
    • Delaminierung des Bahnlaminats und des Überzugsmaterials von dem bildtragenden Medium, indem das Bahnlaminat gegen die Delaminierungseinrichtung geführt wird; und
    • Einstellen der Temperatur der Delaminierungsanordung auf einen Bereichs von etwa 51 bis 71°C (125 bis 169°F).
Anspruch[en]
  1. A system for delaminating a carrier web laminate carrying a protective overcoating material after the overcoating material has been laminated onto an image bearing layer carried on an image bearing medium by heat and pressure applying means; said system comprising: a delaminating assembly; means for advancing the carrier web in a first direction against said delaminating assembly and for advancing the sheet in a direction different from the carrier web so as to effect delamination; and, means for controlling the temperature of the sheet and web in a range of about 51 to 71°C (125°F to 160°F).
  2. The system of claim 1 wherein said temperature controlling means comprises means for actively heating and maintaining said delaminating assembly within said range.
  3. The system of claim 1 wherein said heating means includes at least a heating element within said delaminating assembly for actively heating said delamination assembly to a temperature within said range.
  4. A method of delaminating a carrier web laminate carrying a protective overcoating material after the overcoating material has been laminated onto an image bearing layer on an image bearing medium by heat and pressure applying means; said method comprising the steps of: bending the carrier web against a delaminating assembly and transferring the web in a first direction; advancing the image bearing medium in a direction different from the first direction as the medium is advanced to effect delamination; and, controlling the temperature of the delamination assembly in a range of about 51 to 71°C (125°F. to 160°F).
  5. A method of reducing pinhole formation in an image bearing layer on an image bearing medium which is being delaminated from a carrier web carrying a protective overcoating material thereon, the method comprising the steps of: delaminating a portion of the overcoating material from an image bearing medium by passing the web against a delaminating assembly in a direction which is different than the direction of advancement of the image bearing medium so as to effect delamination of the carrier web from the medium at a delamination point; and, controlling the temperatures of the delaminating assembly in a range of about 51 to 71°C (125 to 160°F).
  6. A system for protecting an image bearing medium carrying an image bearing layer by a heat softenable protective overcoating material carried on a carrier web laminate therefor, said system comprising:
    • a hot roller assembly operating at a first predetermined temperature sufficient to soften at least a portion of said protective overcoating material;
    • a cold roller assembly operating at a second predetermined temperature lower than said first predetermined temperature, said cold roller assembly and said hot roller assembly forming a nip during lamination;
    • a web laminate carrying a heat softenable overcoating material thereon which is adapted for passing between the nip of said roller assemblies for contact with the image bearing layer, said hot roller assembly contacting said web and softening the protective overcoating material, and said cold roller contacting an image bearing medium so that the softened protective overcoating molds onto and adheres to the image bearing medium for forming a bonded image bearing medium;
    • a delaminating assembly located downstream of said hot and cold roller assemblies against which the web engages as it advances in a first direction; and,
    • means for controlling the temperature of said delaminating assembly within a range of about 51 to 71°C (125 to 160°F).
  7. The system of claim 6 wherein: said web laminate comprises a support layer, a release layer, a durable layer and an adhesive layer; wherein said protective overcoating laminates said release layer, said durable layer and said adhesive layer; said adhesive layer and said image bearing layer come into contact when said web and said image bearing medium are juxtaposed within the nip, said support layer contacting said hot roller assembly at the nip, said substrate contacting said cold roller at the nip, and said adhesive layer reaching a glass transition temperature at said nip due to thermal transfer from said hot roller assembly.
  8. A process of protecting an image bearing layer on an image carrying medium with a heat softenable overcoating layer; said process comprising the steps of: juxtaposing the protective overcoating layer and the image carrying medium;
    • heating a hot roller assembly to a first predetermined temperature sufficient to soften the protective overcoat layer;
    • cooling a cold roller to a second predetermined temperature lower than the first predetermined temperature; forming a nip between the pair of roller assemblies and pressing together the hot and cold roller assemblies with a force sufficient to promote adhesion between the softened protective overcoat layer and the image carrying medium; and, bonding together the juxtaposed protective overcoat layer and image carrying medium to form a bonded image bearing medium by feeding the juxtaposed protective overcoating layer and image carrying medium through the nip, said web contacting said hot roller at said nip and said image bearing medium contacting said cold roller at said nip;
    • delaminating the web laminate and the overcoating material from the image carrying medium by advancing the web laminate against the delaminating assembly; and,
    • controlling the temperature of the delaminating assembly within a range of about 51 to 71°C (125 to 160°F).
Anspruch[fr]
  1. Système pour déstratifier un stratifié de film de support supportant un matériau de revêtement protecteur après que le matériau de revêtement ait été stratifié sur une couche de support d'image supportée sur un milieu de support d'image par des moyens d'application de chaleur et de pression ; ledit système comprenant : un ensemble de déstratification ; des moyens pour faire avancer le film de support dans une première direction contre ledit ensemble de déstratification et pour faire avancer la feuille dans une direction différente de celle du film de support de façon à effectuer une déstratification ; et des moyens pour contrôler la température de la feuille et du film dans une plage comprise entre environ 51 et 71° C (entre 125° F et 160° F).
  2. Système selon la revendication 1, dans lequel lesdits moyens de contrôle de température comprennent des moyens pour chauffer activement et maintenir ledit ensemble de déstratification à l'intérieur de ladite plage.
  3. Système selon la revendication 1, dans lequel lesdits moyens de chauffage comprennent au moins un élément chauffant à l'intérieur dudit ensemble de déstratification pour chauffer activement ledit ensemble de déstratification à une température à l'intérieur de ladite plage.
  4. Procédé de déstratification d'un stratifié de film de support supportant un matériau de revêtement protecteur après que le matériau de revêtement ait été stratifié sous la forme d'une couche de support d'image sur un milieu de support d'image par des moyens d'application de chaleur et de pression ; ledit procédé comprenant les étapes suivantes : la courbure du film de support contre un ensemble de déstratification et le transfert du film dans une première direction ; le fait de faire avancer le milieu de support d'image dans une direction différente de la première direction lorsque l'on fait avancer le milieu pour effectuer la déstratification ; et le contrôle de la température de l'ensemble de déstratification dans une plage comprise entre environ 51 et 71° C (entre 125° F et 160° F).
  5. Procédé pour réduire la formation de trous d'aiguille dans une couche de support d'image sur un milieu de support d'image qui est déstratifié à partir d'un film de support supportant sur celui-ci un matériau de revêtement protecteur, le procédé comportant les étapes suivantes : la déstratification d'une partie du matériau de revêtement à partir d'un milieu de support d'image en faisant passer le film contre un ensemble de déstratification dans une direction qui est différente de la direction d'avance du milieu de support d'image de façon à effectuer la déstratification du film de support depuis le milieu en un point de déstratification ; et le contrôle des températures de l'ensemble de déstratification dans une plage comprise entre environ 51 et 71° C (entre 125 et 160° F).
  6. Système pour protéger un milieu de support d'image supportant une couche de support d'image par un matériau de revêtement protecteur pouvant être ramolli à la chaleur supporté sur un stratifié de film de support pour celui-ci, ledit système comprenant :
    • un ensemble de rouleau chaud fonctionnant à une première température prédéterminée suffisante pour ramollir au moins une partie dudit matériau de revêtement protecteur ;
    • un ensemble de rouleau froid fonctionnant à une deuxième température prédéterminée, inférieure à ladite première température prédéterminée, ledit ensemble de rouleau froid et ledit ensemble de rouleau chaud formant un pincement durant la stratification ;
    • un stratifié de film supportant un matériau de revêtement pouvant être ramolli à la chaleur sur celui-ci, adapté pour passer à l'intérieur du pincement desdits ensembles de rouleau pour venir en contact avec la couche de support d'image, ledit ensemble de rouleau chaud venant en contact avec ledit film et ramollissant le matériau de revêtement protecteur, et ledit rouleau froid venant en contact avec un milieu de support d'image de telle sorte que le revêtement protecteur ramolli se moule sur le milieu de support d'image et adhère à celui-ci pour former un milieu de support d'image réuni ;
    • un ensemble de déstratification disposé en aval desdits ensembles de rouleau chaud et froid contre lesquels le film vient en contact lorsqu'il avance dans une première direction ; et
    • des moyens pour contrôler la température dudit ensemble de déstratification à l'intérieur d'une plage comprise entre environ 51 et 71° C (entre 125 et 160° F).
  7. Système selon la revendication 6, dans lequel : ledit stratifié de film comprend une couche de support, une couche de libération, une couche durable et une couche adhésive ; dans lequel ledit revêtement protecteur stratifie ladite couche de libération, ladite couche durable et ladite couche adhésive ; ladite couche adhésive et ladite couche de support d'image viennent en contact lorsque ledit film et ledit milieu de support d'image sont juxtaposés à l'intérieur du pincement, ladite couche de support venant en contact avec ledit ensemble de rouleau chaud au niveau du pincement, ledit substrat venant en contact avec ledit rouleau froid au niveau du pincement, et ladite couche adhésive atteignant une température de transition vitreuse au niveau dudit pincement du fait du transfert thermique à partir dudit ensemble de rouleau chaud.
  8. Procédé de protection d'une couche de support d'image sur un milieu de support d'image avec une couche de revêtement pouvant être ramollie à la chaleur ; ledit procédé comprenant les étapes suivantes :
    • la juxtaposition de la couche de revêtement protecteur et du milieu de support d'image ;
    • le chauffage d'un ensemble de rouleau chaud à une première température prédéterminée suffisante pour ramollir la couche de revêtement protecteur ;
    • le refroidissement d'un rouleau froid à une deuxième température prédéterminée inférieure à la première température prédéterminée ; la formation d'un pincement entre la paire d'ensembles de rouleau et le pressage l'un contre de l'autre des ensembles de rouleau chaud et froid avec une force suffisante pour favoriser l'adhérence entre la couche de revêtement protecteur ramollie et le milieu de support d'image ; et la réunion l'un à l'autre de la couche de revêtement protecteur et du milieu de support d'image juxtaposés pour former un milieu de support d'image réuni en délivrant la couche de revêtement protecteur et le milieu de support d'image juxtaposés à travers le pincement, ledit film venant en contact avec ledit rouleau chaud au niveau dudit pincement et ledit milieu de support d'image venant en contact avec ledit rouleau froid au niveau dudit pincement ;
    • la déstratification du stratifié de film et du matériau de revêtement vis-à-vis du milieu de support d'image en faisant avancer le stratifié de film contre l'ensemble de déstratification ; et
    • le contrôle de la température de l'ensemble de déstratification à l'intérieur d'une plage comprise entre environ 51 et 71° C (entre 125 et 160° F).






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