The value of many food products depends on their shapes. Typically, in the case of frozen confectionery articles, the shape or surface appearance is often a determining factor of the consumer's preference.

The possibility of shaping, embossing or stamping characters or other structures onto the surface of a said product in a quick, efficient and accurate way after the same has been produced is limited. In particular for ice cream products which come out of a freezer at a temperature of about-5° C, there is a tendency for the embossing or stamping tool element to very soon stick onto the surface of the frozen article. A deformation of shape or a poor definition of characters at the surface of the frozen article results therefrom.

In order to avoid such disadvantages, it has been suggested to precool the embossing or stamping element to very low temperature, of the order of-70° C or - 196° C at which the embossing or stamping element will not stick. This can be made by keeping the embossing or stamping element in permanent contact with a cooling source, such as dry ice or liquid nitrogen, e. g. by flushing it with liquid nitrogen.

Another solution to the problem has been suggested e. g. in JP-A-60066941, which consisted in chilling the ice confectioneries to be embossed at a low surface temperature of-20 to-65° C. This solution could be detrimental to the quality of the product, by causing major deformations in product parts not embossed.

Summary of the invention It is an object of this invention to provide a method of performing shaping, embossing or stamping operations which are simple, fast and of low cost without resorting to cooling the embossing or stamping element or the product itself at very low temperatures.

The object is achieved by maintaining all parts of the embossing or stamping element during shaping at a positive temperature of between 0° C and 60° C.

It is a further object of the invention to provide a device for performing the above method.

Brief description of the drawings Further features of the invention will be apparent from the following description of some preferred embodiments of a device of embossing or stamping frozen confectionery with reference to the accompanying illustrative drawings, where: Figure 1 shows a schematic view in simplified form of a system for the production of extruded and embossed ice cream bars, Figure 2 shows a schematic view in simplified form of a system for the production of embossed truncated cone wafer ice creams with round-shaped top and Figure 3 is a detailed view of an embossing device used in connection with the embodiment of figure 1, Figure 4 is a detailed view from below of a stamp used in the embossing device of figure 3, Figure 5 is a front view of an embossed and coated ice cream stick produced as in figure 1 and with the stamp of figure 4 and Figures 6 and 7 outline the principle behind the present invention.

Description of the preferred embodiments As shown in figure 1, heart shaped ice cream bars are prepared form a vertically extruded strand out of a tube 1 of a cross section in the form of a heart, near to a freezer outlet at about-5° C,-6° C, the strand is horizontally cut into slabs 2 and sticks 3 are inserted laterally into the slabs 2 by a stick inserter situated beneath at

the vertical of the extruder head. The slabs are laid out onto plates 4 carried out by a conveyor 5 travelling in the direction of arrow fl.

Right after the stick inserter and before the hardening tunnel 6, the slabs 2 are embossed by means of an embossing device 7 comprising a holder 8 and a stamp 9 situated above the plates 4 at about 5 cm (figures 1 and 3). For operation, the stamp 9 is pushed onto the slab 2 via an air pressure cylinder 10. The up and down movement of the stamp as shown by arrow f2 is controlled by the same signal that activates the stick inserter at the extrusion head.

A proximity switch is installed on the cylinder. When the stamp 9 goes down, to the lowest point of the cylinder movement, the switch is activated and triggers a rapid movement upwards. In this way, a very fast stamp movement into and out of the moving slabs can be obtained, thus avoiding any smearing of the embossed structure due to the movement of the conveyor. Since the slabs 2 are moving horizontally during the embossing process, but the stamp 9 is not, the embossing operation must be fast. Otherwise, the slabs 2 will be pushed sideways by the stamp 9 which may result in an unclear structure.

The stamp 9 is maintained at a temperature above 0° C during the embossing operation. At this temperature, the stamp works well without ice cream sticking to it. Structures are clearly outlined with the stamped surface being smooth. The product surface which is in touch with the stamps melts, leaving a layer of liquid that prevents stickiness.

This principle is outlined in figures 6 and 7 showing the difference of using a stamp 9 at ice cream temperature and down to-70° C (figure 6) in comparison to at temperatures as in the invention (figure 7) at a microstructural level of observation.

In figure 6, the stamp is at about-4° C moving upwards after having touched the freshly extruded ice cream. In the ice cream matrix 38 air bubbles 39 and ice crystals 40 are shown. This matrix has a stick and viscous consistency and contains the soluble and dispersed ingredients such as sugars and proteins in concentrated form. When the stamp 9, being at ice cream temperature or below

down to-70° C, moves up, the matrix will stick to it and gets pulled up thus allowing no clear embossing of structures.

In figure 7, the stamp 9 is at above ice cream temperature, i. e. at about + 10° C.

When the stamp 9 makes contact with the ice cream, it melts the ice crystal at the contact surface. The forming water dilutes the matrix to an ice cream mix 41. The superficial layer 42 of mix forms an insulation between the stamp 9 and the sticky matrix 43. This way, the stamp 9 does not pull up any ice cream and behaves the same way as when dipped into a liquid ice cream mix.

During operation, the stamp 9 may cool down to ice cream temperature, of about - 5° C, which may create stickiness. To keep the stamp 9 from too much cooling, air is blown trough a hole 24 (figures 2 and 4) in the bulk part of the stamp 9. The air may be heated to keep the temperature of the stamp at the desired level of from 0 to 60° C. Another way of controlling the temperature is by electrical heating. To reduce the risk of microbial contamination, the embossing device is preferably kept between 0 and +10° C, using the techniques described above. The temperature can also be raised to high levels to avoid stickiness. A upper temperature of 60° C gives microbiological protection, however, above this temperature, burning effects of liquid product adhering to the hot stamp will have a negative effect on the performance.

After having been embossed on their surface, the slabs 2 are hardened in a hardening tunnel 6. After hardening to about-20° C,-25° C, the slabs 2 are taken off the plates 4 by their sticks 3 and carried away by a conveyor 12 provided with grips 13 for the sticks and dipped into and out of a chocolate bath 14 for coating.

Finally, the coated articles are in line wrapped, e. g. in flow packs 15 and stored at - 20° C or lower.

At figure 2, another application for the embossing device is shown. It concerns the production of a ball top cone, i. e. a cone wafer filled with ice cream which has the shape of half a ball. During production, a perfect shape of half a ball is difficult to achieve since after dosing, some ice cream remains at the top of the half ball in the shape of a pin. This ice cream pin is formed when the dosing device is moved upwards after dosing the ice cream. This ice cream pin is removed by using a metal stamp in the form of half a ball that is pressed onto the ice cream surface

right after dosing the ice cream, before hardening. Using a metal stamp above ice cream temperature, a perfect, smooth surface of the ball top cone is obtained and the ice cream pin is completely removed.

A receptacle 16 is used in the shape of an inverted cone with the apex at the bottom. The receptacle may be shaped differently alltogether, for example as a cup or a truncated inverted cone with flat bottom. The receptacle is supported by an annular holder 17 defining a circular aperture which is smaller in diameter than the outside diameter of the open end of the receptacle, thereby allowing the said receptacle to sit securely within the holder.

The receptacle 16 may be a wafer inverted cone 18 in a sleeve 19 of protective wrapper, e. g. from laminated sheet material, which can be formed from waxed paper with a metal foil flavour barrier and also incorporates decorative labelling.

In other embodiments, the wrapper may include paper, waxed paper, foil or plastics individually or in combination, and in laminate or other form. The receptable 16 comprising the wafer in the sleeve also has a layer of chocolate coating 20 as a barrier against tranfer of moisture. Alternatively, the receptacle may be formed of a chocolate shell in a sleeve wrapper. The receptacle is filled with ice cream 21 at a level over the receptacle edge.

At figure 2, the embossing device 7 comprising a holder 17 and a stamp 9 is situated above the holder at about 5 cm. For operation, the stamp 9 is pushed onto the ice cream mass 21 protruding from the receptacle 16 via an air pressure cylinder 22. The movement of the stamp is controlled by the same signal that activates the dosing device for ice cream. The stamp 9 has the shape of an hemisphere or a dome. The embossing operation is performed as explained for the embodiment of figure 1. After forming the half-bowl, the receptacle together with the ice cream filling can be inverted as shown by arrow f3, coated by dipping it in a chocolate bath 23, the articles are returned to their upright position as shown by arrow f4 and wrapped, e. g. closed by a lid 25 when using cone sleeves.

Alternatively, the articles can be wrapped in flow packs in the case of a truncated inverted cone with flat bottom. After this, the products are hardened and stored as indicated hereinbefore.

As shown in figure 4, the stamp 9 is made of a good thermal conductivity metal.

Since a good stamping result depends on the stamp temperature, it is important to maintain this temperature at all parts of the stamp, comprising on protruding parts and edges. This is done by choosing materials that have excellent heat conductivity values. Aluminium, silver and copper can be used and aluminium is preferred for reasons of cost, machinability, it can be carved with simple tools, and low weight. The low weight of aluminium is important to allow a fast movement of the stamp.

The design of characters or numbers such as 26 on the stamp 9 are preferably big and simple for best visibility. Structures are preferably not below 3 mm wide to appear clearly, even after coating with chocolate. Although small details can be embossed easily, the coating of chocolate will later cover them up. If this technique is used for products which are not covered with chocolate, smaller details will remain visible and more details can be included in the design of the stamp.

The depth of embossing is preferably not below 4 mm for producst that will be coated in chocolate after embossing. Close structures such as an O require special attention to give a good imprint. When the stamp touches the ice cream during the embossing operation, the air inside the O cannot escape and thus ice cream will not fill out the inside of the O. In an embodiment, a tiny hole 27, e. g. of a section of about 1 mm, is in the center of the O, building a channel 28 leading to the side wall of the stamp that will allow air to escape. Alternatively, the ring of the O or the curve of a ciffer five can be opened for a O or is opened in several places for the five, e. g. the upper right part 29 and lower left part 30 of the five, allowing the air to escape. The same rule apply to other structures that may entrap air during the stamping operation. The characters of the stamp should preferably protrude out of the base plane by about 6 to 8 mm where possible, so that the base plane will not touch the ice cream surface. Preferably, the sidewalls 31 of the characters define a slope at an angle of 10° to 20°, preferably about 15°.

As shown in figure 3, the embossing device 7 comprises a hanger 32 which is substantially perpendicular to the plate conveyor 5 on which the holder 8 is pivotably mounted. The holder 8 comprises a first supporting plate 33 on which the stamp 9 is attached and a second plate 34 supporting the air cylinder 10 and

which is parallel to the first plate 33. Supporting plates 33 and 34 can vertically slide the one with respect to the other for easy adjustment of the stamp, plate 33 sliding and being guided along slit 35 in plate 36 which latter is fixed to plate 34.

Air ducts 37 allow for vertical up and down movement of cylinder 10.

In the above description of preferred embodiments of the embossing device, only one line of products is shown. Of course the same principle can be used for embossing several lines of products with multiple embossing devices and stamps which can be on a common or on different frames without departing from the spirit and scope of the present invention.