DEVICE FOR PRINTING SPHERICAL OBJECTS AND THE LIKE

Abstract: A method and device for printing three-dimensional objects, characterised in that the means for transferring the inked design between a flat master surface from which said design is to be picked up and a three-dimensional object which is to be printed is constituted by a hollow resiliently deformable stamp (1) which is preferably hemispherical in shape and which, when pressed onto the master is capable of deformation to provide a flattened surface which allows said pick-up to take place and, when pressed onto a three-dimensional object (5) to be printed is capable of deformation to envelope the object over a surface area of substantially a hemisphere, this being the surface area to receive the inked design.

Description: TITLE: DEVICE FOR PRINTING SPHERICAL OBJECTS AND THE LIKE TECHNICAL FIELD The invention relates to a device for printing on three- dimensional bodies, and more particularly but not exclusively for printing on spherical or part-spherical bodies, and to a method of printing using such a device. BACKGROUND ART Until now, characters, designs, colours and the like have been printed on spherical objects and the like by the same method as when printing on flat surfaces by methods, including stamping, which use an intermediate element or stamp which picks up an inked design from a master and transfers it to the object to be decorated or printed. At present, the design solution adopted with said stamps is to make them from solid rubber or similar synthetic materials. This solid form means that, when a spherical object is to be stamped, the adaption of the stamp to the shape of the object takes place solely through elastic deformation of the material of which it is made. Thus the surface area which the stamp can cover is very limited, being confined to small areas. In fact, since the stamp has to be flat in order to be able to take the corresponding inked design from a flat master surface and, since it is solid, adaption of the same to the spherical object takes place solely through elastic deformation of the material of which the stamp is made; therefore, it can only reach very small surface areas. Solutions designed to solve this problem while retaining the solid design of the stamp and giving it certain moulded shapes corresponding to those of the item to be decorated by printing have not been very successful on account of the complexity of producing such stamps and the means required for the initial transfer of the inked design onto them. This is the situation which currently exists, for example, in the synthetic plastics balloon and ball manufacturing industry;these items are either decorated with very limited designs as regards the surface area covered or else recourse is had to successive stamping operations, successively turning the spherical object being stamped, making the printing operation slow and expensive. At all events, up to now, no process had been found which allows large surface area of spherical objects - which may be a semi-spherical object - to be stamped in a single operation. DISCLOSURE OF INVENTION According to the present invention, this feature is achieved with a novel design of stamp i.e. the solution has been achieved by breaking with the traditional moulds which " have a solid stamp, and by developing a new design according to which said stamp comprises a flexible hollow body. According to one embodiment, said flexible hollow stamp takes the form of a thin hemispherical hood which is fixed round its rim to a plate held by mechanical means which perform the appropriate raising and lowering movements onto the object to be printed. The hollow interior of the stamp and its inherent flexibility enable it to conform to any solid object and also to the flat surface of the master where the ink is collected. In fact, when the stamp of the present invention is lowered onto the inked master design disposed on a flat surface and is pressed against it, it is flattened agatint the master and picks up the inked design correctly. When this inked design is separated from the flat master, the hollow stamp recovers its intitial shape as a hemisphere and, when it is placed on the spherical object to be printed and is pressed against it, its hollow form and flexibility again enable it to adapt to the spherical form of said object, surrounding it practically as a hemisphere and printing the corresponding design onto this surface. Thus, in a non-limiting example of the printing of balloons or balls, practically half a balloon can be stamped in a single operation and it is only necessary to turn it through one hundred and eighty degrees. Alternatively opposed stamping devices can be employed. If desired the hollow flexible stamp can be filled with some material which, by enabling it to deform precisely, provides it with the proper consistency and, moreover ass±sts it to recover its form elastically after each deformation. In this connection, said filling material will preferably be a fluid. The above description has been provided in order to facilitate an understanding of the invention in the form of one; possible example in which the objects to be printed are spherical and the stamp is a hollow flexible hemisphere; obviously, in the invention, the essential point is the hollow flexibLe design of the stamp since this has to adopt the^shape of a spherical hood of greater or lesser dimensions orran other similar shape, with a working surface which is preferably rounded. Likewise,, the object being,.printed may be- spherical or any other three-dimensional shape as the invention is valid for printing the concave and the convex parts of an object where it is also suitable for printing hemispherical and semicylindrical interiors and the like. \. ~ B-_-R--_--I-__E_-_F_- M ---D-----E----S-__CR-----I-_--P__-T-_---I----O____-N--__-- H^ O--F---------D--_RAWINGS The invention is diagrammatically illustrated, by way of example, in the accompanying drawings in which:- Figure 1 is an elevation of a pair of stamps which are ready to operate on respective spherical objects; Figure 2 is a view similar to that of Figure 1 but with the stamps in contact with the objects to be printed; Figure 3 is a section of the stamp taken on the line III - Ill of Figure 1 , and Figure 4 is a section of the stamp taken on the line IV- IV of Figure 1. Explanatory details 1. - Stamp 5 2. - Hemispherical hollow stamp body 3. - Stamp support structure 4. - Rod 5__ - Object to be printed 6. - Object support ~ Q BEST MODE FOR CARRYING OUT INVENTION The object of this invention is a method of and device for printing spherical objects and the like starting from a general printing line which includes the corresponding elements for metering and preparation of inked surfaces and 15 also stamps which are the means of transfer between said inked surfaces and the object to be decorated. According to the invention, each stamp (1), see Figure 1, is constituted by a body in the form of a hollow flexible hemispherical hood (2) which is fixed to a support structure (3) which in turn 0 is fixed to a ' rod (4) which may be connected to a conventional means which provides the necessary translation, raising and lowering movements. As can be seen in Figures 3 and 4, the hood (2) consists of a laminar hollow elastic element which, starting from its 5 convex external shape, can adapt to any object through the effect of the pressure exerted by the rod (4), conforming its external surface to that of the object to be printed and, consequently, transferring the inked design to an object equivalent in area to a hemisphere in one step. As can be seen in Figure 1, the object (5) to be printed, which in this case is a spherical object such as a balloon, is held under the stamp (1) by means of fastening device or support (6) . The printing process, according to the present invention is as follows: Firstly, each stamp (1) moves until it is located on the flat master template whic.h incorporates the inked design which is to be printed. In this position, the stamp (1) descends, applying pressure, and, since the stamp (1) is hollow and flexible, it deforms and, as it is flattened against the flat template, it adopts the shape of a flattened hemisphere which, at its pole, provides a flat surface constituting a good recipient for the inked design incorporated on the template., , Once the inked design has been transferred to the stamp (1), the latter rises and moves until it is over the object to be printed (5) as shown in Figure 1. ■ The stamp (1) is then lowered and again, being a hollow flexible body, it deforms and envelopes the object (5) as shown in Figure 2. In this way, it prints the design which it had taken from the flat template on to this object (5) and, through the envelopment of the object (5), said printing can cover practically half of this object (5), i.e. a hemisphere. If desired the stamp (1) may incorporate a filling material in its hollow interior, which material helps to provide the body (2) with required resiliency and helps it recover its initial shape elastically. In this connection, said filling material will preferably be a fluid, either gaseous or liquid, which will leave the body (2) when the latter deforms and return to the inside of the body automatically when the deformation ceases. Thus when several stamps- (1) operate in synchronism, the fluid from some of the interiors of some of the stamps can pass into others in closed circuits, i.e. while some stamps (1) are being deformed, the others are recovering their initial configuration. Obviously, this filling matrial could be a solid or particulate having sufficient elasticity without in any way altering the essence of the invention. INDUSTRIAL APPLICABILITY In one possible practical embodiment of a stamping line for spherical objects (5), groups of four stamps (1) will be arranged for the four basic colours of the colour combinations and these four stamps (1) will produce the corresponding final design which will cover half an object (5), either through successive operation of the same or through simultaneous operation and successive feeding of the objects (5). It will be sufficient to turn this object (5) through one hundred and eighty degrees or else to arrange groups of stamps (1) in positions opposite one another in order to cover practically all the object (5) in one stamping operation. Obviously, the description which is given of one possible practical embodiment is not intended to be taken as limiting since the objects (5) to be printed may have any known three-dimensional shape-or may even be flat, although it is clear that,the invention has been specifically designed in order to print three-dimensional objects. These objects (5) can have a convex or else concave form in the external configuration of their surface to be printed. Likewise, the fundamental shape of the body (2) of the stamps (1) may be spheroid, cylindrical or cylindroid etc., without departing from the scope of the invention as defined in the following claims.

Claims: CLAIMS 1. A device for printing three-dimensional objects, characterised in that the means for transferring the inked design between a flat master surface from which said design is to be picked up and a three-dimensional object which is to be printed is constituted by a hollow flexible stamp (1) which, when pressed onto the master is capable of deformation to provide a flattened surface which allows said pick-up to take place and, when pressed onto a three-dimensional object (5) to be printed is capable of deformation to envelope the object over a surface area of substantially a hemisphere, this being the surface area to 'receive the inked design. 2. A device for printing three-dimensional objects as claimed in claim 1 , characterised in that the hollow flexible stamp (1) consists of a hollow body (2) the interior of which is occupied by a material which allows the stamp to be deformed and assists in the elastic recovery of its original shape. 3. A device for printing three-dimensional objects as claimed in claim 2 , characterised in that the material in the hollow body (2) is a fluid. 4. A device for printing three-dimensional objects as claimed in any preceding claim, characterised in that the hollow body (2) of each stamp (1) is generally hemispherical in shape which when applied to a spherical object to be printed covers substantially a hemispherical part of it. 5. A method of printing on the surface of a three- dimensional object using a device as claimed in any preceding claim, characterised by the steps of pressing the hollow flexible stamp (1) against a flat inked master surface whereby the design to be printed is transferred to the surface of the stamp, removing the hollow flexible stamp from the master surface, pressing the hollow flexible stamp against the three-dimensional object (5) so that it envelopes the three-dimensional object and its inked surface is brought- into contact with the surface of the object (5) whereby the inked design is transferred to t ' he abject.

Inventors: GURPEGUI JOSE, GURPEGUI, JOSE
Applicants: UNICE SA, UNICE, S.A.
Application year: 1986
Main classification: B41F17
IPC codes: B41F17