AU706808B3 - Mould plates for making chocolate products - Google Patents

Description

MOULD PLATES FOR MAKING CHOCOLATE

PRODUCTS

This invention relates to the production of mould plates for use in the manufacture of chocolate products.

More specifically this invention relates to mould plates for use in the production of chocolate products having pictures, designs and logos marked thereon and particularly an image with photographic likeness. It also extends to the manufacture of chocolate products from these mould plates. Logo chocolates are typically formed from top and bottom mould plates within which two colours of chocolate are respectively received.

Up to now engraving techniques have been used to form the design in the mould plates. However, it typically takes an engraver several hours to produce a single mould, and the cost is therefore fairly high. In addition, the tolerance or sharpness of the moulds is not very high, and this adversely impacts the sharpness of the logo images on the chocolates. A yet further limitation of engraving is that it is limited to producing a single tone logo design on a chocolate. It cannot be used to produce more complex pictures, eg half tone photograph-like pictures.

Accordingly, it would be advantageous if a more efficient and effective method of forming mould cavities in mould plates used for making chocolate products could be devised.

According to an aspect of this invention there is provided providing an image on a film of the design to be reproduced, the image contrasting with the film background, one of the image and background being transparent and the other of the image and background being Tdark, and also providing a photopolymeric plate having a polymer which cures and hardens on exposure to UV radiation; positioning the film between a UV source and the photopolymeric plate with the film substantially in alignment with the printing plate; irradiating the film with UV radiation such that the radiation passes through the transparent areas of the film and irradiates the corresponding portion of the photopolymeric plate, and radiation is blocked by the dark areas on the film so that the corresponding portion of the photopolymeric plate is not irradiated; washing the photopolymeric plate so as to remove soft uncured polymer from the printing plate so as to define a relief mould and then drying and post exposing the photopolymeric plate to provide a suitably hard relief mould surface; using said photopolymeric plate as a first mould plate together with a second complementary mould plate in a mould assembly for moulding chocolate; introducing flowable chocolate of the first colour into the mould cavity of the first mould plate and then wiping off excess chocolate; placing the second mould plate over said first mould plate substantially in alignment with the first mould plate; introducing flowable chocolate of a second colour into the mould cavity of the second mould plate such that it covers the exposed chocolate in the first mould plate; and cooling the chocolate in respectively the first and second mould plates to as to permit the two colours of chocolate to solidify and harden and adhere to each other and then removing a chocolate product having a design in chocolate of the first colour thereon from the mould plates.

Preferably the image on the film is dark and the background is transparent, and said second mould plate is bendable or deformable, and one of the chocolates is of a light colour and the other chocolate is of a dark colour and the plates are washing for a duration of 350 to 450 seconds during said washing step.

Advantageously the UV radiation is directed into the photopolymeric plate at an angle which has the effect of causing the polymer to cure in an angled line rather than a vertically extending line.

Preferably the angling of UV radiation is accomplished by placing a transparent sheet over the positive film during irradiation with UV radiation, the rays of UV radiation being directed inwardly at an angle by refraction.

This feature results in the walls of the mould cavity of the finished mould being angled eg inwardly which eases removal of chocolate from the mould.

The positive film may be a half-tone film which produces a profile of varying depth in the photopolymeric plate, the depth at any given point on the plate corresponding to the tone or level of darkness of the corresponding point on the half-tone film.

A method of forming a mould plate and chocolate product in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe in detail one preferred embodiment of the invention with reference to the accompanying drawings. The purpose of this specific description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. It is to be clearly understood, however, that the specific nature of this description does not supersede the generality of the preceding broad description. In the drawings: FIG. 1 is a schematic three dimensional view of a machine suitable for use in carrying out the method of the invention; FIG. 2 is a schematic three dimensional drawing showing exposure of a photopolymeric plate with UV radiation as occurs in the machine of FIG.

FIG. 3 is a schematic exploded three dimensional view of a mould assembly for making chocolate products in accordance with the invention; FIG. 4 is a sectional view of the first mould plate of the assembly of FIG.

3 in use filled with chocolate of a first colour; and FIG. 5 is a schematic sectional view of the mould assembly of FIG. 3 with the mould cavities of the first and second mould plates both filled with chocolate.

FIG. 1 illustrates a machine for carrying out the method of the invention. In FIG.

1 the machine is referred to generally by reference numeral 1.

The machine is contained in a chest-like housing 2. The machine contains broadly, means for placing a photopolymeric plate 10 and film 8 in the machine and a UV source 12 for exposing the film 8 and plate 10 to UV radiation.

The plate placing means is provided by an exposure drawer 4 which is a sliding drawer in the housing 2 which has a vacuum bed for holding the plate 10. The drawer 4 slides outwardly out of the front of the housing 2 for insertion and removal of a positive film 8 and the photopolymeric plate 10. The film 8 lies directly on the surface of the photopolymeric plate 10 with emulsion down. A clean sheet of plastic (not shown) is rolled over the film and plate and smoothed over to remove air bubbles. The film drawer 4 is positioned below the UV source 12. Thus UV radiation has to first pass through the sheet and the film 8 before it can expose or irradiate the photopolymeric plate 10. The plate rests on the surface of the drawer 4.

The upwardly opening top 3 of the housing is a washing bed. In addition, the machine also includes a control panel 6.

The UV source 12 comprises at least one tube which radiates ultraviolet energy and which is energised by an electrical supply which is coupled to a domestic ains supply.

The machine 1 also contains brushes (not shown) which are used in a washing process described in more detail below to remove uncured polymer from the plate 10. The brushes are resiliently mounted on a brush support within the housing so that the brushes apply a constant pressure to the plate.

The photopolymeric plate 10 comprises a fairly rigid backing plate 11 covered by a layer of uncured polymer 13 which contains UV free radical initiators. The polymer is catalysed or cured by irradiation with UV radiaition. Polymers of this type which cure in this fashion are well known to persons skilled in the art and accordingly will not be described in further detail.

Typically the backing plate 11 is made from a metal such as aluminium although obviously a stiff sheet of plastic could also be used. The polymer 13 typically has a thickness of about 0.67 mm although other thicknesses may also be used to carry out this method. The plate 11 which the applicant uses in the method described above are commonly available photopolymeric printing plates. The plates 10 are exactly the same as normal commercial every day printing plates.

In use, when a new design is required for chocolate products, the first step is to scan or develop a design using design software on a computer and produce a transparent positive film for use in the machine. This positive film 8 is made using standard commercial techniques used in the printing industry. As these would be well known to persons skilled in the art they will be described in further detail in the specification. Typically the production of the film is out-sourced to a commercial laboratory although obviously this need not be the case.

After the film 8 has been produced it is loaded into the exposure drawer 4 of the machine 1 with a printing plate 10. A plastic sheet of matte finish (not shown) is rolled over the film and plate and a vacuum is then applied. The sheet is then smoothed over to remove air bubbles.

The UV source 12 is then energized irradiating or exposing the positive film 8 to UV radiation. The film 8 casts an image onto the printing plate 10 and UV ation passes through the film and strikes the plate 10 where the image of the film 8 permits this to occur. If the photopolymeric printing plate 10 is viewed as a matrix of dots or local areas, some of the dots will have been irradiated with UV radiation and cured, and other dots will remain soft and uncured due to the UV radiation being blocked by opaqueness in the positive film 8.

Typically the plate 10 is cured with UV radiation for 350 to 450 seconds, eg about 400 seconds. The polymer in the plate 10 is tolerant to some variation in the exposure time but a substantial over exposure of the plate 10 can have a deleterious effect on the quality of the plate. The clear plastic sheet described above which was mounted on the film in the exposure drawer during the exposure stage has the effect of refracting UV radiation at an angle onto the photopolymeric plate. This has the effect that the polymer cure in angled or inclined lines rather than vertically extending lines. This affects the angle of the walls of the mould cavity which result when the plate is washed in the washing step.

After the radiation or exposure step has been completed, the film is removed and the plate 10 is washed with water for about 350-450 seconds, eg about 400 seconds at a temperature of up to 26 0 C. The washing step is carried out in the washing bed described above. The washing is assisted by the brushes which remove soft uncured polymer from the plate 10 leaving only the polymer which was cured and hardened by the exposure step.

The walls of the mould cavity are inclined at an angle to the vertical of about 600, preferably about 450 rather than being vertically extending. This feature confers benefits later on when the photopolymeric plate 10 is used as a mould plate in the manufacture of chocolate products. The inclined walls enable the chocolates to be removed from the mould more easily than with vertically extending walls with less risk of damage to the chocolates.

After the washing step is completed, the plate 10 is dried. Drying is achieved by heating the machine up to 60-80 0 C for thirty minutes. Thereafter the entire ,_late is once again exposed to UV radiation in a post exposing step for about 400 seconds to cure all polymer on the plate. This provides a hard polymeric plate 10 suitable for use in making chocolate products. The plate 10 can then be removed from the machine 1 and used in the manufacture of chocolate products using two complementary mould plates.

FIGS. 3 to 5 illustrate mould plates forming a mould assembly 20 for use in forming logo style chocolate products.

The mould plate 10 illustrated in FIG. 4 is made in accordance with the method of the invention using the machine illustrated in FIG. 1.

The mould assembly 20 comprises broadly a first mould plate 22 having a recessed relief mould cavity 23 defined therein. The first mould plate 22 is made in accordance with the method described above with reference to FIGS. 1 and 2.

The second mould plate 24 is formed from a sheet of rubber typically which is flexible. The second mould plate 24 defines a mould cavity 25 therein, eg a rectangular opening, which defines the shape, size and thickness of the chocolate product formed by the mould assembly. Typically the second mould plate 24 is made from flexible material which does not slip when placed in abutting contact with the polymer of the first mould plate 22.

In use in the production of chocolate products, chocolate 26 of a first colour, eg white chocolate, is spread over the relief mould cavity 23 on the first mould plate 22 such that it fills up the mould cavity 23. Typically this is done manually with a spatula 28 or spreader although obviously the chocolate may also be poured into the mould cavity 23. Excess white chocolate is then wiped off the first plate 22 so that the only chocolate remaining is that which is received within the cavity 23 of the first plate 22.

The second mould plate 24 is then placed over the first mould plate 22 with the second plate in alignment therewith so that the mould cavity 23 of the first plate opens into the mould cavity 25 of the second plate 24. Chocolate of a second colour 29, eg brown, is then poured into the second mould cavity which is filled with chocolate. Again any excess chocolate is removed from the second mould plate 24 by means of a spatula or spreader.

The mould assembly 20 is then placed on a conveyor and passed through a cooling tunnel to cause the chocolate to cool and harden. When the assembly emerges from the downstream end of the cooling tunnel the chocolate has been hardened into its final consistency. The chocolate product with logo is removed from the mould assembly by first of all removing the first mould plate 22 to expose the face of the chocolate with the logo thereon. The chocolate product is then pushed out of the opening in the second mould plate 24 to produce a product which is ready for packaging and distribution.

The description above has been confined to a mould plate having one mould cavity thereon. However it will be readily understood that the first and second mould plates may each have a plurality of mould cavities defined therein, eg arranged in a rectangular array and that these plates can be used to produce a plurality of chocolate products, eg 20 to 30 products at one time. It will also be readily understood that the use of mould plates having a plurality of mould cavities thereon would probably lead to greater productivity in commercial production.

The method of the invention has been described above with reference to logo chocolates. However it can also be used with half tone positive films to produce mould plates suitable for use in producing chocolates having photograph-like or real life pictures thereon (photograph chocolates).

To produce photograph chocolates a half tone positive film 8 is used in the machine 1. The half tone film 8 comprises a series of black dots, the tone or degree of darkness at any point on the film being determined by the size of the black dots. Dark areas have large black dots with little or no spacing between adjacent dots and light areas have small dots with large transparent spaces in between the dots.

Areas of intermediate tone have medium sized dots. The production of half tone films for use in this process is a standard procedure in the photographic and/or printing industries and would be well known to persons skilled in the art.

Accordingly it will not be dealt with in further detail in the specification.

Applicant has ascertained that a screen ruling of 85 lines of dots per square inch for the half tone film is particularly suitable for carrying out the invention. A screen ruling of 133 lines of dots per square inch proved less satisfactory.

During the exposing and washing step, the half tone film yields a mould cavity 24 in the polymeric plate of complex and varying relief profile, the depth of the mould at any point being dependent on the degree of darkness on the corresponding point of the transparent film. The spacing between the dots determines how much UV radiation passes through the film, which in turn determines the depth of the mould cavity at any point on the plate. The plate is then used in the production of chocolate products according to the process described above. Applicant has discovered that these plates can be used to produce attractive photograph chocolates, which the applicant believes will have great appeal in the market place. Applicant is not aware of any other way of producing photograph chocolates, which contain only chocolate products and not a superimposed non-edible photograph.

Applicant has conducted extensive tests of chocolates made with polymeric printing plates. The tests showed that chocolates made according to the method described above did not contain any impurities or other organic compounds. The analysis and tests were conducted by the Australian Government Analytical Laboratories in Pymble in New South Wales.

An advantage of the method described above with reference to the drawings is that the mould plates can be used to produce very clean and sharp logo image chocolates, eg single tone pictures.

A further advantage is that the costs of producing a mould plate, by the method described above is substantially lower than for an engraved mould plate. In addition it is possible to tool up a mould plate to produce a new design for a chocolate product much quicker than when engraving is used.

A yet further advantage of the method described above is that it can be used to produce photograph-like or real life pictures and applicant envisages that there will be a large demand for this type of chocolate product. Applicant has thus found that the method described above has a greater capability than engraving techniques.

It will, of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is herein described in the appended claims.

Claims (3)

1. A method of reproducing an image from a film on a chocolate product, the method including: providing an image on a film of the he design to be reproduced, the image contrasting with the film background, one of the image and background being transparent and the other of the image and background being dark, and also providing a photopolymeric plate having a polymer which cures and hardens on exposure to UV radiation; positioning the film between a UV source and the photopolymeric plate with the film substantially in alignment with the printing plate; irradiating the film with UV radiation such that the radiation passes through the transparent areas of the film and irradiates the corresponding portion of the photopolymeric plate, and radiation is blocked by the dark areas on the film so that the corresponding portion of the photopolymeric plate is not irradiated; washing the photopolymeric plate so as to remove soft uncured polymer from the printing plate so as to define a relief mould and then drying and post exposing the photopolymeric plate to provide a suitably hard relief mould surface; using said photopolymeric plate as a first mould plate together with a second complementary mould plate in a mould assembly for moulding chocolate; introducing flowable chocolate of the first colour into the mould cavity of the first mould plate and then wiping off excess chocolate; placing the second mould plate over said first mould plate substantially in alignment with the first mould plate; introducing flowable chocolate of a second colour into the mould cavity of the second mould plate such that it covers the exposed chocolate in the first mould plate; and cooling the chocolate in respectively the first and second mould plates to as to permit the two colours of chocolate to solidify and harden and adhere to each other and then removing a chocolate product having a design in chocolate of the first colour thereon from the mould plates.

2. A method according to claim 1, wherein the image on the film is dark and the background is transparent, and wherein said second mould plate is bendable or deformable, and wherein one of the chocolates is of a light colour and the other chocolate is of a dark colour, and wherein the plates are washed for a duration of 350 to 450 seconds during said washing step.

3. A method according to claim 1 or claim 2, wherein the positive film is a half tone film which produces a profile of varying depth in the photopolymeric plate, the depth at any given point on the plate corresponding to the tone or level of darkness on the corresponding point on the half-tone film. DATED THIS Thirtieth DAY OF April 1999. CHOCOLATE .:.GES PT LTD 9\ L ck BY /cST 7 PIZZEYS PATENT AND TRADE MARK ATTORNEYS