ADVERTISING INDICIA ON A CONVEYOR BELT

Abstract: Disclosed is a conveyor belt, the belt comprising a substrate layer (1, 2, 3, 4) with an information (6) display formed on the uppermost surface thereof, and wherein the substrate layer is overlaid by one or more transparent or translucent coating layers (5) of a thermosetting plastic material such that the information display is visible therethrough.

Description: Title: ADVERTISING INDICIA ON A CONVEYOR BELT Field of the Invention This invention relates to a conveyor belt and to a method of making a conveyor belt. Background of the Invention Conveyor belts are well known devices used to convey objects or materials from one place to another, for example they are used in supermarket check-out stations to convey the products that the customer has chosen to the check-out assistant, who then enters their price into their till (typically by scarning a bar code), and places them onto an area where they can be packaged. Similar belts are also used in industrial situations (e.g. on production lines). Sometimes it is desirable to print information on the top, conveying surface of the belt, for example to give the belt manufacturers' name, or technical information. In addition, the present inventor considers that it would be desirable to use a conveyor belt as an advertising medium, for example in supermarket check-out stations. Printing information onto the top surface of a conveyor belt has been performed previously, but a problem has arisen in that the printed area is abraded by the continuous flow of objects being conveyed, so that within a relatively short time the printed area becomes unreadable or non-acceptable in appearance. US Patent 4,979,591 discloses a conveyor belt having a multiple fabric layer overlayed with a thermoplastic material, such as poly vinyl chloride (PVC). An image is then transferred to the PVC layer by transfer printing (i.e. sublimation printing), in which process a dyesheet contacted with the belt is locally heated to cause local sublimation of the dyestuff on the dyesheet and transfer onto the PVC layer of the belt. The resulting image on the upper surface of the belt is then covered with a film of transparent plastic, but there is no teaching or suggestion in US 4,979,591 as to the identity of a material suitable for use as the transparent film. The purpose of the plastic film is to protect the belt, and the transfer printed image thereon, from abrasion and scratches. Naturally the plastic film must be transparent, otherwise the printed image on the belt will not be visible through the plastic film. Transfer printing, of the type disclosed in US 4,979,591 is not ideal, as it tends to lead to the formation of diffuse images. In addition, some colours (especially white) are not readily available as transfer dyes. WO 97/43125 discloses a method of making a conveyor belt, in which an image is formed on a PVC belt by silk screen printing. The inks forming the image are caused to adhere to the PVC substrate by subjecting the printed belt to a heat treatment, comprising blowing air at about 80°C over the belt for a period of approximately 15 seconds. The resulting printed belt may optionally be provided with a coating of a conventional, clear PVC varnish. In both US 4,979,591 , and WO 97/43125, an image is formed on the belt when the belt is already in its substantially finished form. As there are severe constraints on the thickness of the belt, (e.g. so as to be usable with existing equipment intended for use with conventional conveyor belts), there is little possibility of adding a thick protective layer over the image, with the result that the image is vulnerable to abrasion and scratching. Summary of the Invention In a first aspect the invention provides a conveyor belt, the belt comprising a substrate layer with an information display formed on the uppermost surface thereof and wherein the substrate layer is overlaid by one or more transparent or translucent coating layers of a thermosetting plastic material such that the information display is visible therethrough. Conveniently, the coating layer will form a substantially continuous coating on top of the substrate layer, which arrangement facilitates manufacture. For present purposes, a thermosetting material is a material which requires the application of heat for the material to harden. Thermosetting materials, in particular, may be distinguished from varnishes which harden as a result of solvent evaporation, and will therefore harden at room temperature within a relatively short period of time. The information display may comprise letters (especially words), numerals, images or any combination thereof. In particular the information display may comprise advertising or promotional material. Preferably the information display is formed on the substrate by a means other than transfer printing. Preferred methods of forming the information display comprise inkjet or laser printing or, more preferably, silk screen printing. Preferably the information display is formed by the use of acrylic-based inks. Silk screen printing allows for the formation of an information display of far greater resolution than is obtainable by transfer printing. The substrate layer may itself be laminate in nature. For example, the substrate layer may ty pically comprise one or more tabπc las ers (e g comprising w oven poly ester material) and one or more resin lay ers (e g comprising P\ C or similar resinous material ) In one embodiment the substrate la\ er comprises a bottom lav er ot tabπc and a top la\ er ot resin, w ith information display ed on the surface of the resin lay er In a preferred, alternatne. embodiment the substrate layer comprises a first resin lay er sandw iched between t o fabric layers w ith a second resin lay r on top ot the upper fabric 'av r w ith information displac d on top of the second resin lay er The coating lay er may comprise am translucent or transparent thermosetting material which is compatible w ith the substrate lay er and suitable for use in a convey or belt Preterabh the coating layer prov ides good resistance to abrasion and thereby prolongs the time over which the information displayed on the substrate layer beneath, remains isible The coating la er should be able to bond to the substrate lay er and/or the information display ed thereon so as to be resistant to delamination In addition the coating layer should preferably be resistant to cracking and should not become opaque w ithin a short period of time The present in entor has found transparent or translucent formulations comprising PVC are preferred Typically a belt in accordance w ith the invention will comprise 4 or 5 layers of transparent PVC resin, which prov ides excellent resistance to wear and abrasion In a preferred embodiment the substrate layer of the belt (especially the uppermost surface thereof) w ill comprise an opaque thermosetting PVC resin layer, w hich is of substantially similar composition to the thermosetting PVC resin transparent or translucent material used to form the coating layers The material can be rendered opaque, w hen used tor the substrate layer by the addition ot a suitable pigment (e g carbon powder for a black- coloured belt, oxides ot zinc or titanium tor a white-coloured belt) The inventor has found that coating a conveyor belt ith a PVC v arnish, as disclosed in WO 97/43125, does not provide adequate protection for the displayed information which soon becomes worn and illegible In contrast, prov iding a PVC coating as a numbεi of layers of thermosetting material creates a tar stronger protecti e 'shell " In addition the prov ision ot the one or more coating layers serves to bind the display ed information to the substrate la er ithout the need tor the heat treatment step taught in WO 97 43125 Further, convey or belts in accordance w ith the inv ention ha e tar thicker coating layers overly ing the information displayed on the belt than those disclosed in the prior art w hilst still hav ing a thickness essentially identical to that ot unconv entional unpπnted convey or belts This is achiev ed by forming the information display on the belt at an earlier stage in its construction whilst still unfinished The partly-made, printed belt may then be completed and brought to the thickness of conventional conveyor belts, by the application of the coating layers Typically 4 or 5 separate layers of transparent PVC resin are applied to build up the coating layer, and hence the belt as a whole, to the desired thickness Each separate layer ot transparent P\ C resin is cured (by heating) before the next layer ot resin is applied In a second aspect the invention provides a method ot making a conveyor belt having information displayed thereon, the method comprising the steps of making a substrate layer, printing on the uppermost surface ot the substrate layer information to be displayed thereon, and coating the printed surface ot the substrate layer with one or more transparent or translucent coating layers ot a thermosetting plastic material such that the displayed information is visible therethrough It will be apparent to those skilled in the art that the printing step is performed whilst the belt is still only partly -made, hich allows for a considerable thickness of coating layer to be applied on top of the displayed information, leading to superior protection of the display against wear, abrasion and scratches Preferably the uppermost surface of the substrate layer is formed from one or t o layers of opaque thermosetting PVC resin The coating layers will have a substantially similar composition, but ill be transparent or translucent (I e not contain any added pigment) Preferably the method is such that, when performed, it results in the production of a conveyor belt in accordance ith the first aspect of the invention defined above The invention will now be further described by way of illustrative example and with reference to the accompanying drawings, in which - Figure 1 is a diagrammatic sectional view, showing the construction of a conventional "two ply ' conve or belt ot the type used in supermarket check-out stations, with printing on its top. l e conve ing surface. Figures 2 and 3 are diagrammatic sectional views showing intermediate steps in the construction ot a con e or belt in accordance ith the in ention. Figure 4 is a diagrammatic sectional view of a two ply conveyor belt in accordance ith the invention. Figure 5 is a diagrammatic sectional view of a conventional "single ply" conveyor belt; and Figure 6 is a diagrammatic sectional view of a "single ply" conveyor belt in accordance with the invention. Referring to Figure 1, a fabric layer 1, generally made of a woven polyester material, is coated with a layer of liquid plastisol PVC resin 2. A further layer 3 consisting of woven polyester fabric is placed onto the PVC layer 2. This sandwich is heated to bond all three layers such that the PVC layer 2 penetrates partially into the woven fabric layers 1 and 3 but does not bleed through it. A further liquid layer of PVC 4 is then coated onto the top of the fabric layer 3 and cured. The coating thickness of layer 4 has a maximum of typically 0.3 to 0.4 mm, which is not thick enough to provide the mechanical properties required for the belt, so a further layer 5 of PVC, again with a typical thickness 0.3 to 0.4mm, is coated onto layer 4 and cured. Additional layers of PVC may be added to increase the belt thickness as desired. Conventional printing onto the top surface of the belt is shown as 6, for example by silk screen. In this typical construction the layers of PVC 4 and 5 are pigmented and are opaque. Since there is no coating overlying the printed image 6, the image is vulnerable to abrasion and scratches. Figure 2 shows the construction of a typical conveyor belt as described for Figure 1 , but shows the process has been arrested after layer 4 has been applied. Figure 3 shows a printed area 6 on top of layer 4. This printing can be done by conventional methods, for example by means of silk screen printing, using inks which are compatible with PVC and will bond strongly with it. In Figure 3, layers 1-4 together constimte the substrate layer 7. Figure 4 shows the finished belt comprising a coating layer 5 which is transparent and which will bond strongly with layer 4 and with the printed ink 6 so that delamination will not occur. Typically the transparent coating is provided in four or five separate layers. The thickness of the transparent coating layer 5 is generally selected to be the same as on a conventional belt, and could for example consist of PVC polymer. This transparent layer protects the printed areas from abrasion by the objects being conveyed on the belt whilst allowing the printed areas to be viewed. Other configurations of this invention may be used, for example the fabric layer 3 could itself be printed by conv entional means such as silk screen printing w hich is then subsequently coated ith one or more layers of transparent PVC or other transparent materials The aforementioned processes relate to w hat is know n as a tw o ply PVC flat conveyor belt, the ply referring to the numbei of fabric lay ers Thei e are other including a single ply P\ C flat conv ey or belt The current inv ention can be applied to the single ply PVC belt as follows Figure 5 show s diagrammatically the construction of a conventional single ply PVC conveyor belt, where a woven polyester fabric layer 10 is coated on us top side with one or more layers 12. 13 of liquid PVC, each coat being cured before the addition of the next Figure 6 shows printed areas 14 which are applied onto layer 12. which typically is a pigmented PVC polymer In Figure 6, layers 10 and 12 together constitute the substrate layer 7 After the printed area is cured, a transparent PVC coating layer 13 is coated onto the printed area and substrate layer Some applications tor these belts require that the top surface is of a matt finish to prevent reflection from ov erhead light sources This can be achieved by mechanically texturing the surface whilst it is still soft, using a textured roller or by having a polymer with a chemical formulation that produces a non reflective surface This may be a polymer such as PVC or polyurethane

Claims: Claims 1. A conveyor belt, the belt comprising a substrate layer with an information display formed on the uppermost surface thereof, and wherein the substrate layer is overlaid by one or more transparent or translucent coating layers of a thermosetting plastic material such that the information display is visible therethrough. 2. A conveyor belt according to claim 1 , wherein the one or more transparent or translucent coating layers form a substantially continuous coating on top of the substrate layer. 3. A conveyor belt according to claim 1 or 2, wherein the substrate layer is laminate in nature. 4. A conveyor belt according to any one of claims 1 , 2 or 3, wherein the substrate layer comprises one or more fabric layers and one or more resin layers. 5. A conveyor belt according to any one of the preceding claims wherein the one or more transparent or translucent coating layers comprise PVC resin. 6. A conveyor belt according to any one of the preceding claims, wherein a transparent or translucent coating layer is bonded to the substrate layer so as to resist delamination in use, and wherein the coating layer is resistant to cracking. 7. A conveyor belt according to any one of the preceding claims, wherein information is applied to the uppermost surface of the substrate layer by means of a silk screen printing process. 8. A method of making a conveyor belt having information displayed thereon, the method comprising the steps of: making a substrate layer; printing on the uppermost surface of the substrate layer information to be displayed thereon; and coating the printed surface of the substrate layer with one or more transparent or translucent coating layers of a thermosetting plastic material such that the displayed information is visible therethrough. 9. A method according to claim 8, wherein an information display is printed on the uppermost surface of the substrate layer by means of silk screen printing. 10. A method according to claim 8 or 9, performance of which results in a conveyor belt in accordance with any one of claims 1-7. 11. A conveyor belt substantially as hereinbefore described and with reference to the accompanying drawings. 12. A method substantially as hereinbefore described and with reference to the accompanying drawings.

Inventors: PAYNE JOHN MICHAEL, PAYNE, JOHN, MICHAEL
Applicants: MARKET IDEAS LTD, PAYNE JOHN M, MARKET IDEAS LIMITED, PAYNE, JOHN, MICHAEL
Application year: 2000
Main classification: B65G15
IPC codes: B65G15