ERASABLE WRITING DEVICE

Abstract: An erasable label device without a frame or border having first layer (40, 50) which comprises a foil of translucent flexible synthetic plastics material coated on one surface thereof with a releasable adhesive layer arranged to overlie a second layer (52) comprising a dark surface; in which said adhesive layer is formulated to permit releasable adhesive with the dark surface to locate the first layer on the second layer and the foil and the dark surface are chosen so that they releasably adhere to one another so that the dark surface shows through the foil locally where and when the foil is urged onto the dark surface by means of a dull pointed instrument thereby to record writing on the label which writing may be erased by lifting the first layer from the dark surface.

Description: ERASABLE WRITING DEVICE This invention relates to an erasable writing device particularly but not exclusively such a device in the form of a label which may be attached to a video or audio tape cassette identifying the material which may have been recorded on tne tape. Devices, often referred to as magic slates or pads, are known (see for example UK patent specification No. 1,389,438) which consist of:- 1) A black card coated on one side with wax, 2) An opaque white tissue, which under pressure, adheres to the black card and shows it through, even if only a fingernail is used, 3) A celluloid, polyester, or similar transparent sheet of hard plastics material over the other two layers to prevent the writing implement from tearing the tissue, 4) An erase bar which slides up and down between the adhering tissue and the waxed black card in order to separate them for erasure, 5) A rigid frame, guide or runner to assist either the pad or the erase bar in its movement and alignment, and 6) A rigid back-plate, which holds the whole unit together and serves to grip the waxed black card, tissue and transparent top protective layer together at both ends. These devices have been known for many years and have been used principally as toys or notepads. But because of their necessary thickness and rigidity, they cannot be used in applications where flexibility, flush exterior or close fit are important, for example in identity labels for folders or video-cassettes and similar items. It has been realised in this invention that such articles whose status or contents are frequently changed would particularly benefit from the use of such a labelling system if it can be made less bulky. The erase bar and its travel guides are a major cause of bulk. But frames or borders, whether to hold the entire assembly together or to effect erasure by hinging open and shut are also too bulky when the depth of the average label well on a video cassette, for instance, is between one third and one half of a millimetre and a label should not stand proud of this well. Borders or frames are not only bulky, but may be insecure and vulnerable. It should be appreciated that manufacturers will not redesign or retool the standard video cassette to accommodate these frames or borders and their concomitant additional thickness or requirements (see UK Patents. 2055702 and 2130,631) and labelling the video cassette box, (such as described in UK Patent No. 2,055,702) is disadvantageous since the latter is being frequently mislaid or misplaced. Bordered or framed labels may also be insecure or vulnerable to knocks or scuffs whilst being inserted into, or extracted from, players, groups on library shelves, filing cabinets etc. Also the frame or border occupies too much of the available writing area when the spine label well on a video cassette, for instance, is only twenty millimetres wide. Also bordered or framed labels are costly in manufacture; in a highly competitive field the video cassette affords very small profit margins. Accordingly the present invention provides an erasable label device without a frame or border having first layer which comprises a foil of translucent flexible synthetic plastics material coated on one surface thereof with a releasable adhesion layer arranged to overlie a second layer comprising a dark surface; in which said adhesive layer is formulated to permit releasable adhesive with the dark surface to locate the first layer on the second layer and the foil and the dark surface are chosen so that they releasably adhere to one another so that the dark surface shows through the foil locally where and when the foil is merged onto the dark surface by means of a dull pointed instrument thereby to record writing on the label which writing may be erased by lifting the first layer from the dark surface. In one preferred arrangement, said first layer is so coated with releasable adhesive only on edge regions of said one surface and said dark surface is coated with or compromises a further releasable adhesive material to so releasably adhere to said translucent foil. In a further preferred arrangement said first layer is so coated with releasable adhesive over substantially the whole of said one surface to releasably adhere to the dark surface. Preferably in such case the dark surface is roughened. In yet a further preferred arrangement the invention provides an erasable label device without a frame or border having a first layer which comprises a foil of translucent flexible synthetic plastics material coated on one surface thereof with a releasable adhesive layer, adhesive means at one edge of the foil to attach the foil permanently to a roughened dark surface; the arrangement by such that the foil releasably adheres lightly to the dark surface to locate the foil thereon and releasably adheres heavily to the dark surface so the dark surface shows through the foil locally where and when the foil is merged onto the dark surface by means of a dull pointed writing implement thereby to read writing on the label which writing may be erased by lifting the first layer from the dark surface. In this specification and Claims, the term "releasable" in respect of adhesives refers to adhesives such as an acrylic, a silicone gripping adhesive, a hydrogel or any other material or formula being of the kind that permits disengagement and re-engagement any number of times without noticeable loss of adhesion. The term "permanent" in respect of adhesives refers to adhesives which form a bond which is not released in normal use. Erasure of writing on the label devices is effected by lifting the first layer thus separating it from the second layer. The first layer is then allowed to fall back into position, influenced by its own rigidity. In order to promote a fuller understanding of the above and other aspects of the invention, some embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:- FIGURE 1 is a schematic side elevation and part section example with both solid layers turned up not to scale, and FIGURE 2 is a perspective view showing the label applied to a video cassette spine, and FIGURE 3 is an alternative embodiment shown in elevation. The erasable label device in Figure 1 is in the form of a label comprising a first layer 50 of flexible transparent plastics material. Along the longitudinal margins on the back of the layer 50 there is provided a coating of low-tack -releasable adhesive 51 capable of being dis-engaged and re-engaged without noticeable loss of adhesion. The layer 50, is hingedly connected at one end 50a by permanent adhesive 32 or welding (fusion) to a second solid layer 52 providing a dark surface, preferably black, having a coating of releasable adhesive (or wax) 53 thereon, over substantiall the entire upper surface. The layer 52 has on its back surface a permanent adhesive 54, protected until the moment of use, by a peel-off strip 55. For erasure the layer 50 is lifted at one end, remote from the hinge end, away from the releasable or waxed surface 53 by a grip tag 56 until resistance is felt due to the fixed hinge. Re-application of the layer 50 to a re-usable position is facilitated by the hinge which ensures accurate re-alignment, its rigidity which ensures location and the adhesive thereupon which re-grips the dark surface. The first layer can be transparent or translucent, if transparent the adhesive will be translucent, if translucent the adhesive may be transparent. The first layer may have a smooth upper surface and a 'frosted' under surface, this being another means of assisting in doing away with the previous system's opaque layer. The first layer can be of polyester, polypropylene, cellulose acetate or any resilient plastics material. The first layer may be 50-200 microns thick in order to both re-align and afford itself its own protection so that it does not rely on a transparent protective layer. When less than 50 microns thick, it is more pliable to permit the writing, but in order to return of its own volition it requires the greater thickness. It is possible to use less than 50 microns of thickness in the writing area and to laminate an additional thickness elsewhere to act as a return spring for the entire layer. The first layer may border level with the bottom layer so that the releasable adhesive 51 contacts the bottom layer's upper coating 53. The formulae of the two adhesive surfaces are to be compatible. Alternatively, the first layer may overhang the bottom layer so that adhesive 51 contacts the surface of the host object. The former configuration may be preferable particularly where the host object is of an unstable material such as paper. The grip-tag 56 may be formed by: (a) an uncoated portion of the end of the first layer, (b) a coated but doubled over portion of the end of the first layer, or (c) a small segment of another material laminated to the end of the first layer (and is on the opposite end to the welded end. ) The first layer releasable adhesive margins are preferably 2.0 mm wide. The dark surface may have a permanent adhesive 55 coating on its underside to enable it to: (a) adhere temporarily to a releasing carrier sheet until required and (b) adhere permanently to a host object as and when required. The dark surface may be introduced on a foil of 75-200 microns thick including adhesive layers 53, 54 on each side respectivel . In a simplified example of the invention shown in FIGURE 3, the second solid layer of the above described example is dispensed with. Instead a label is provided which can be used in conjunction with a suitably roughened surface preferably embodied in the side of a video or audio cassette tape, the roughened surface serving to provide the required. The simplified form of label comprises a flexible translucent or transparent plastics layer 40 carrying on its back surface an even coating 41 of releasable transparent or translucent, respectively in relation to the material of the strip 40 adhesive of a kind which is capable of being dis-engaged from an inert surface and re-engaged without loss of adhesive quality. This adhesive is also capable of being locally deformed from its backing by pressure and returning to its former shape. One end of the layer 40 is arranged to be hingedly connected by a permanent adhesive coating 42 protected prior to use by a tear-off backing strip 44 to a co-operating dark surface. A grip tag 45 is attached by a permanently settable adhesive at the distal end of the strip 40. The dark surface to which the label of FIGURE 3 is to be applied, such as the side edge surface of a video cassette is roughened, ie it has a series of raised portions, dots or peaks and valleys. Preferably the roughened surface is formed on the cassette during moulding by a pattern, spark eroded (or laser etched) into the mould. The combined area of the peaks is from 5% to 20%, preferably 10%, of the area of the surface and serves to support and engage the releasable adhesive. The remaining area of the surface comprising the valley regions remains free of the low tack adhesive until pressure is supplied by a writing implement which deforms the adhesive into contact with the valley surfaces to retain the image. The number of peaks per square centimetre of area of the dark surface should be from 400 to 500, preferably 450. There is also an important relationship between the coat weight of the adhesive and depth of the valley regions in the roughened area in that one must be able to contact the other. A typical preferred thickness of adhesive and depth of valley is 12.5 microns. In general terms it is important to achieve a balance between the height, shape, density and size of the peaks; the hardness, thickness and opacity of the adhesive; and the pliability of the translucent layer. Also in this embodiment the surfaces may be reversed so that the label surface or adhesive may be patterned and the dark surface on the host object smooth and opaque. The roughened dark surface described and used with the embodiment of FIGURE 3 may also be used on the second layer 52 of the embodiment described with reference to FIGURE 1. The labels of the present invention may, in one specific instance (video cassette spine) be in total one third to or, half of a millimetre thick, 20 mm wide and 150 mm long. In manufacture, one or more of the adhesives may be applied in pre-coated form by a process of fine lamination rather than direct coating. In this instance any additional layers or coatings occurring would be to facilitate the manufacture of, rather than the operation of the invention. If greater return spring abil ty of the first layer is required, selective area lamination to additional thickness material may be effected.

Claims: CLAIMS 1. An erasable label device without a frame or border having first layer (40,50) which comprises a foil of translucent flexible synthetic plastics material coated on one surface thereof with a releasable adhesive layer, arranged to overlie a second layer (52) comprising a dark surface; in which said adhesive layer is formulated to permit releasable adhesion with the dark surface to locate the first layer on the second layer, and the foil and the dark surface are chosen so that they releasably adhere to one another so that the dark surface shows through the foil locally where and when the foil is urged onto the dark surface by means of a dull pointed instrument thereby to record writing on the label, which writing may be erased by lifting the first layer from the dark surface. 2. An erasable label device as claimed in Claim 1, in which said first layer is so coated with releasable adhesive only on edge regions of said one surface and said dark surface is coated with or comprises a further releasable adhesive material to so releasably adhere to said translucent foil. 3. An erasable label device as claimed Claim 1 or 2, in which said second layer further comprises a backing foil (52) for said dark surface (53). 4. An erasable label devise as claimed in Claim 3, in which said backing foil is provided with an adhesive coating (53) by means of which the label may be attached to an object to be labelled. 5. An erasable label device as claimed in Claim 1 in which said first layer (40) is so coated with releasable adhesive over substantially the whole of said one surface to releasably adhere to the dark surface. 6. An erasable label device as claimed in Claim 5, in which said dark surface or said one surface of the first layer is roughened. 7. An erasable label device as claimed in Claim 6, in which said roughened surface comprises peaks and valleys regions, the peaks comprising between 5% and 20% of the area of the roughened surface. 8. An erasable label device as claimed in Claim 7, in which said peaks comprise 10% of the area of the roughened surface. 9. An erasable label device as claimed in Claim 7 or 8, in which there are between 400 and 500 of said peaks per square centimetre of said roughened surface. 10. An erasable label device as claimed in Claim 9, in which there are 450 of said peaks per square centimetre of said roughened surface. 11. An erasable label device as claimed in any preceding claim, in which said first and second layers are permanently attached together at one edge thereof by means of a permanent adhesive or welding (50a). 12. An erasable label device as claimed in any preceding claim, in which said first layer is provided with a grip tab (45, 46) arranged so that the first layer may be peeled away from the second layer thereby to erase any writing on the label . 13. An erasable label device as claimed in any preceding claim, in which said dark surface is embodied in an item to be labelled. 14. An erasable label device without a frame or border having a first layer (40) which comprises a foil of translucent flexible synthetic plastics material coated on one surface thereof with a releasable adhesive layer (41), adhesive means (42) at one edge of the foil to attach the foil permanently to a roughened dark surface; the arrangement being such that the foil releasably adheres lightly to the dark surface to locate the foil thereon and releasably adheres heavily to the dark surface so the dark surface shows through the foil locally where and when the foil is urged onto the dark surface by means of a dull pointed writing implement thereby to record writing on the label, which writing may be erased by lifting the first layer from the dark surface. 15. An erasable label device as claimed in Claim 4, in which said first layer is provided with a grip tab (45) at an edge opposite to said one edge arranged so that the first layer may be peeled away from the dark surface thereby to erase any writing on the label.

Inventors: COLLINS STEPHEN, COLLINS, STEPHEN
Applicants: COLLINS STEPHEN, COLLINS, STEPHEN
Application year: 1989
Main classification: B43L1
IPC codes: B43L1