WO2018202328A1

WO2018202328A1 - Tampon printing method for printing foodstuffs, and foodstuff ink

Info

Publication number: WO2018202328A1
Application number: PCT/EP2018/000209
Authority: WO
Inventors: Martin Manns
Original assignee: Kellermeister Manns Gmbh
Priority date: 2017-05-04
Filing date: 2018-04-18
Publication date: 2018-11-08
Also published as: DE102017004260A1

Abstract

A tampon printing method for printing foodstuffs with curved pressure-sensitive surfaces by means of a soft tampon and a rapidly drying foodstuff ink and, furthermore, an edible foodstuff ink of this type and the use thereof are described. There is a need for a method which is suitable for printing pressure-sensitive foodstuffs such as fruit or vegetables with an edible ink. This is made possible by way of a tampon printing method for printing foodstuffs with curved pressure-sensitive surfaces by means of a soft tampon and a printing ink which is suitable for tampon printing, wherein - a rapidly drying foodstuff ink is used as printing ink, - the tampon has a degree of hardness of from 60 to 20 Shore 00 Si, and - the printing operation is carried out within a time window of from 1.0 to 3.5 seconds. For example, apples or else chocolate-covered marshmallows can be printed with one colour or with multiple colours.

Description

description

Pad printing process for printing on foodstuffs as well

Food coloring

The invention relates to a pad printing method for printing on

Foods with domed pressure-sensitive surfaces by means of a soft tampon and a fast-drying food coloring, furthermore such a consumable food coloring and its use.

Applying easily variable information to foods is often useful and desirable. An example of such a need exists in the case of fruits or vegetables; d. H. traders' desire to provide fruit or vegetables with a "PLU code." This PLU code is important for the retailer to indicate the correct price, for example, based on fruit size Furthermore, it is desirable, for example for brand recognition, to have a company logo, but also advertising messages,

Manufacturer information or the like to apply to the food.

On the market, information is currently being applied to foods, such as food. Fruits and vegetables usually by labeling with stickers or by using tools such as wrapping in printed paper or attaching tags to stalks. Stickers often do not adhere adequately to uneven or waxed surfaces. A major disadvantage is also that the consumer must remove the aforementioned tools before consumption, which is not always easy with adhesive labels.

Some fruits, such as apples, also have the option of working with templates during the ripening process on the plant. When harvesting, the template is removed and the apple peel is at this point for example, yellow in contrast to the otherwise red shell of the apple. This method is quite elaborate, only in the last weeks of the

Ripening processes take place on the tree, the contours are not very sharp and can continue to fade when ripening. A free choice of color is not possible.

A comparatively new method is lasers. Due to the rounding of fruit, the area to be lasered is very limited because the laser is quickly out of focus and thus no longer works. For example, the area to be "imprinted" on an apple is no more than 30x20 mm Another disadvantage of the method: The laser alters or destroys cells or cell contents on the surface, thus reducing its durability The contrast of laser engraving is very low. A free choice of color is not possible here either.

Another way of applying information is through printing techniques such as stamping. The printing or stamping of objects with non-flat surfaces such as eggs, but also fruit, has been the subject of patents early on, for. GB 334,735,

Even with these techniques, there are certain difficulties. In direct contact printing e.g. Stamping is a good print quality when printing uneven surfaces, if you z. B. fruit and vegetables such as oranges, apples, grapefruit and the like, difficult to achieve. Often the necessary contact pressure during stamping is so high that damage occurs on sensitive surfaces.

One printing method that overcomes these disadvantages would be

Tampon printing process. Clear contours, different colors or even

Multicolor, low contact pressure and the printing of relatively large areas, which may be irregularly shaped, would be possible. DE 38 36 142 describes a device for printing thin-shelled

Items (like eggs) using pad printing.

Among other things, on the Internet, some companies advertise that also fruit can be printed in a pad printing process, e.g. tampondruck.giano.de/. However, only fruits (bananas, mandarins or oranges) are listed, where the shell is not consumed. At sweet-promo.ch you will find this note: "Attention: you can only print fruits that are peeled / no apples".

The reason for this seems to be that there are no approved food safe colors (food colors) that are suitable for tampon printing.

This is supported by the fact that in the book of the company Microprint for tampon printing (download: microprint.ch/pdf/Tampondruck-Buch.pdf) under the chapter "colors" finds the explicit statement: "food colors can with the

Pad printing can not be transferred. "

In this picture also fits that the company Tampoprint, whose founder is the inventor of pad printing, and which claims to be leader in the field of pad printing, in their website next to a selection of other printed products, not a printed, but a lasered Apple shows (see tampoprint.de/de/aktuelles/aktuelles-zum-tampondruck.html).

Food colors for printing on food are known in principle and are the subject of numerous patents, mainly for ink-jet printing (for example DE 697 29 080). However, these colors are not suitable for pad printing.

In principle, therefore, edible colors can also be applied to foods with the ink jet printing method. However, this method is subject to restrictions. The technique of contactless Ink jet printing is particularly useful for applying indicia to foods with a flat surface, e.g. B. in confectionery, pies and confectionery. In these cases, the inkjet printing process is compared to

Shock pressure method such. As stamping, in which the items are easily damaged, often preferred. Difficulties arise in this method, however, in printing surfaces that are irregular, in particular curved. In principle, this method has similar limits in this respect as lasing.

The above statements indicate that there is a need for a method that is suitable for printing on pressure-sensitive foods such as fruits or vegetables with an edible color. The object of the invention is to provide such a method.

This object is achieved by the present invention according to claim 1.

Another problem associated with the direct labeling of food such as. However, fruit is, for example, that the information on the fruit under a variety of conditions readable and even in the presence of

Moisture must remain stable. Since fruit in packaging or boxes is exposed to frequently changing temperature and humidity conditions during storage, transport and display in the supermarket, condensation or moisture may form on the surface of the fruit. The

Pressure information on the surface of the fruit should be stable even under such varying temperature and humidity conditions and sudden

Changes remain legible. The printed image should not fray, fade, fade or be in any other contact with it under any conditions or environmental changes to which the fruit may be exposed

Dye food.

There is also a need for a color suitable for consumption, such as tampons, fruit and vegetables such as apples, tomatoes and with information. The color should be fast and without

Smearing the printed image, drying, condensate and water

be moisture resistant and do not run when exposed to moisture.

Furthermore, the food color should be used as possible

be tasteless, so they can also be eaten with fruits and vegetables, in which the shell is usually eaten.

Food law matters must be fulfilled.

Another object of the invention is to provide such for the

Pad printing to provide suitable printing ink

This object is achieved by the present invention according to claim 6.

In order to overcome the described disadvantages of the prior art, the pad printing method according to the invention for printing on foods with curved pressure-sensitive surfaces is proposed. This

Printing is done by means of a soft tampon and a fast-drying food coloring. The printing process is carried out within a specific time window.

In principle, the process can print all foods with a firm, if possibly sensitive, surface. As sensitive surfaces are to be regarded as those by already relatively low mechanical stress, especially pressure, especially if this by means of a

Articles, such as stamping, are damaged in their structure, so that the quality of the food is impaired. Examples of this are apples and nectarines from the fruit sector, and tomatoes and avocados from the vegetable sector. They have in common that they can easily get unsightly bruises, which are often not only a visual impairment, but also to unwanted Flavor changes lead, if not even starting points for decay and mold. Furthermore, sensitive surfaces may also be those which are easily breakable. This is especially true for hollow bodies. Examples include hollow bodies, such as balls, eggs or other figures, which consist of edible, solid masses, for example chocolate. Even extremely sensitive chocolate kisses are to be printed using the new technology. In principle, it is also possible to print by means of the method according to the invention pastry and other baked goods, meat products such as sausage and dimensionally stable cheese.

For the purposes of the invention are referred to as curved surfaces those that are not substantially planar. Curved surfaces may at least approximately correspond to surface segments of geometric bodies. In the case of apples or tomatoes, the surfaces to be printed correspond approximately to the surfaces of segments of a sphere, cucumbers and zucchinis more closely to those of a cylinder and, in the case of radishes or carrots, to those of a cone. Also saddle-shaped or otherwise irregularly curved surfaces, as in

Animal figures fall under it. Furthermore, the surface may be substantially smooth, as with apples or tomatoes, but it need not, but may also have some roughness and structural irregularities, as is the case with avocados or citrus fruits.

If such partially irregularly shaped surfaces are to be printed, the pad printing process offers a number of advantages that the

Person in the field of printing technology are known in principle.

Particular attention should be paid to the choice of a suitable tampon. According to the invention, a soft to very soft tampon is preferred, because with increasing hardness of the tampon also increases the risk that the surface of the food to be printed is damaged. Therefore, according to the invention, tampons are preferred which have a degree of hardness of 60 to 20 Shore Si, in particular 40 to 20 Shore Si, depending on the sensitivity of the article to be printed. It is also at

comparatively strongly curved surfaces with a soft tampon to achieve a better print result. For large apples, therefore, a hardness of 40 to 30 Shore 00 Si may still be practicable, for tomatoes one of 30 to 25, for thin-walled chocolate hollow bodies one of 25 to 20, especially for chocolate kisses one of 22 to 20.

Another part of the invention relates to the additional reduction of

Hardness of an already soft tampon by means of heat treatment. Thereby, soft tampons, e.g. of about 25 Shore 00 Si, depending on the desired target hardness between 30 and 120 minutes exposed to a temperature of 60 to 100 ° C. In this process, the degree of firmness of the tampon continues, e.g. reduced to about 20 Shore 00 Si.

Alternatively, a so-called hollow tampon can be used, so a

Tampon, which is made hollow between tampon carrier and printing surface. This achieves an optimum adaptation of printing surface and printing surface at approximately the same pressing pressure.

Important is the optimal adaptation of the tampon in the middle of the

Pressure surface, where the pressing pressure is strongest. This area, which first touches the printing surface, is arched well into the hollow tampon during printing, the distortion is minimized and the printed image becomes more precise.

Although working with a hollow tampon is a viable alternative, a heat-treated full tampon provides better results in terms of handling and printed image. For the purposes of the invention, the best printing results of round

Drucktampons achieved with curved pressure surfaces, since here a

Rolling movement is possible on all sides. This uniform rolling motion allows the tampon to absorb the color optimally and

then release without air inclusions. It is therefore preferable to work with a round tampon. Alternatively, you can work with a rectangular, voluminous tampon at its base. In both cases, the tampon tapers towards the pressure surface and ends with a curvature.

Corresponding forms are commercially available.

The printing behavior of the tampon is determined not only by its shape and physical training, but also significantly by the material from which it is made. For the purposes of the invention, tampons of silicone rubber, preferably of an additively crosslinked one, are particularly suitable

Silicone rubber.

The addition of additives can modify the surface of the printing pad. These additives regulate the outward diffusion or migration of silicone oil, which is responsible for the surface texture. The expert speaks here of tend to be damp or dry designed

Pad surfaces. Damp printing tampons have a slightly thicker paint application, which allows better ink coverage. It is therefore advantageous that the tampon material contains additives that release migrating silicone oils.

With the right choice of a suitable tampon is also accompanied by the choice of optimum contact pressure. This depends of course on the sensitivity of the surface to be printed. In the case of an apple, for example, it should not be more than 160 N / m ² , for a ripe tomato not more than 100 N / m ² , for a chocolate-nut not more than 70 N / m ² . Since the present invention is directed to sensitive surfaces, the tampon is pressed at a pressure of only 70 to 160 N / m ² onto the surface to be printed. A preferred range for fruits is 100-160 N / m ² at Chocolate hollow figures 100-120 N / m ² , with chocolate kisses max. 70 N / m ² . This is currently the most common application, such as apple printing. It makes little sense to go to the maximum lower limit of the contact pressure for each object to be printed if the surface tolerates a higher pressure. The person skilled in the art will be able to determine the optimum setting by simple tests. However, you can go to very sensitive or strongly curved surfaces, such as tomatoes or cherries to the lower limit.

As can be seen from the above description, the method according to the invention is particularly suitable when it comes to the domed,

pressure-sensitive surface is one of such fruits or vegetables. For approximately spherical bodies, ie those in which the surface to be printed corresponds approximately to the surface of a spherical segment, the size of the printable surface is dependent on the diameter of the body. For example, for a small apple with a diameter of about 70 mm, a field of about 45 x 45 mm, for a large apple with a diameter of about 85 mm a field of about 60 mm x 60 mm can be printed.

Furthermore, the method according to the invention is also particularly suitable if the curved, pressure-sensitive surface is possibly a hollow body filled with liquid, in particular those which would be damaged or broken if the contact pressure is too high. Such hollow bodies can be made, for example, from thin-walled chocolate and be present in different forms, for example as balls, eggs, animal figures or Santa Claus. The hollow bodies can also be filled, for example with a liquid. As an example of a very thin-walled, sensitive and filled hollow body, chocolate kisses should be mentioned.

The inventive method is based on a new, suitable

Combination of the technical features mentioned in the main claim. This includes both a suitable color, but also as an essential feature, printing is done within a time window of 1 to 3.5 seconds. A range of 1.7 to 2.2 seconds is preferred.

The food grade solvents, e.g. in the form of

Alcohols have a temperature-dependent evaporation rate. Therefore, the window of time between color pickup on the cliche and color output on the print object is limited in time. Too short a time window results in the color not being completely dispensed, a too long window of time for the color to dry on the tampon and not being indicated, and the cliche is closing. The time window is therefore ideally at a room temperature of 20 ° C 1, 7 - 2.2 seconds.

Of course, a suitable color for the process according to the invention must be a food coloring. It must be suitable for consumption and thus without damaging effect on the human organism. Usually, such colors are subject to a state approval procedure. The constituents contained should either be easily used by the organism or excreted unchanged.

Basically, such paints contain a coloring component and a film-forming binder dissolved or dispersed in a predominantly

organic solvents. Small amounts of water are possible as well as property-improving additives, for example emulsifiers,

Dispersing aids, stabilizers, flow and thickening agents and

Viscosity improvers. It can not always be strictly distinguished between emulsifiers, dispersants, stabilizers and solubilizers. Often the terms are even used synonymously. All ingredients should be physiologically harmless. Shellac can be used as a suitable film-forming binder. Suitable organic solvents are

straight-chain lower alcohols having 2 to 4 carbon atoms. As the coloring component, pigments such as titanium dioxide, vegetable charcoal or allura red AC can be used. An ink suitable for human consumption according to the invention for printing on foodstuffs by means of pad printing has one

Content of (in parts by weight)

20 to 40 shellac

30 to 70 polar organic solvents

6 to 40 dye

0 to 3 water

0.5 to 3 solubilizers

0 to 5 additives

in total, 100 parts by weight result.

Preferably, the polar organic solvents are lower alcohols, especially those having 2 and 4 carbon atoms. They are volatile, that is, they have a high vapor pressure at room temperature and evaporate quickly without appreciable residue. Particularly preferred are ethanol and n-butanol-1, which are also well utilisierbar. Preference is given to a combination of solvents with the main component ethanol having an evaporation number of 8.3. Secondary component is preferably n-butanol-1 with an evaporation number of 33.

Titanium dioxide (white), vegetable charcoal (black) or allura red AC (red) can be used as the coloring component, also referred to as dye. Other coloring components are possible in principle.

Shellac may be esterified up to 50% in order to improve film formation or to improve its incorporation into the paint during its production.

It is preferred to use natural lecithin as solubilizer in the paint

use. Preferably, the color contains lecithin which has been obtained from soy. Furthermore, as additives natural flow and thickening agents and waxes may be included. Particularly suitable is a white color, as these of the more dark backgrounds, the fruit, vegetables or chocolate usually form, stands out particularly well. Preference is given to a white color with the following

Composition (in parts by weight)

24 to 28 shellac

35 to 40 ethanol

20 to 24 titanium dioxide

11 to 15 n-butanol-1

0.5 to 2 lecithin

in total, 100 parts by weight result.

This color can be processed particularly well in the process according to the invention. Therefore, the use of this color is preferred.

It is particularly advantageous if the paint has a viscosity in the range of 50 to 80 s when measured with a Ford cup No. 4. If the viscosity is too high, the cliché will increase. If the viscosity is too low, the printed image will be dirty and the opacity will decrease. Preferred is a paint having a viscosity which is in the range of 60 to 70 seconds when measured with a Ford cup # 4.

The printing inks of the invention are particularly suitable for use in the process according to the invention.

In several operations, different colors can be applied, so that the result is multicolored images.

In particular, in so-called open color systems, the viscosity of the color is observed, since solvent evaporates from the color in the open container. Therefore, the viscosity must occasionally be corrected in accordance with the time and the clock frequency. For this purpose, the printing process is stopped and solvents, such as ethanol, mixed. With the method according to the invention there are many possibilities for applying information directly to the surface of food. This can be, for example, a company logo, a brand, advertising messages, manufacturer information or even codes. Commonly used and applicable with the method according to the invention codes include the already mentioned PLU codes, but also EAN codes and QR codes. As with barcodes or barcodes, care must be taken when applying QR codes that the highest possible contrast is achieved. The ideal black and white is often not possible, depending on the surface of the food. However, many readers can recognize other representations, such as inverse (white on black) or colored. All that is required is that the code as a whole has a uniform contrast. In principle, modifications of QR codes, such as design QR codes or frame QR codes, can also be applied using the method according to the invention. QR codes can be used, for example, as an aid in logistics, but also in advertising, QR codes keep moving in, as they allow the customer to quickly access additional information such as product videos or websites via a smartphone. You can also link QR codes directly with the possibility to download programs, eg via app stores.

For large runs, the printing process can be automated.

Conveyor belts can transport the objects to be printed under the tampon or the tampons and also remove them again in accordance with the printing frequency. Furthermore, in the case of pad printing machines with a plurality of tampons (for example 4 pieces), provided that a corresponding number of objects to be printed is simultaneously transported, precisely this number can be printed within one cycle. Important for this type of

Automation is the holder for the print object. This should not be able to move after inserting. Especially when

For multicolor printing, the object must always be hit exactly in the same place for each individual color from the tampon. Recording is therefore of particular importance for print quality. More about automation can be taken for example from the above-mentioned book of Fa. Microprint for pad printing.

Examples:

Example 1 :

As objects to be printed, apples with a diameter of about 75mm were chosen. These were previously stored for 24 h at the same temperature that prevailed in the pressure chamber. In this case, the apples were tempered to 15 ° C. If necessary, in individual cases, the apples with a

Cleaned cotton cloth. An alcohol-resistant printing plate with a motif size of 45 x 45 mm, which was specially produced, was used. The

Exposure time for the print motif was 45 seconds, for the raster film (80 raster) another 45 seconds. The product picking device for apples was fixed to the machine.

By means of viscosity meter white food color was checked to the desired viscosity (70 s with Ford cup 4), if necessary. Readjusted by adding ethanol and the color then filled into the machine. A tampon with a hardness of 40 Shore 00 Si was used. The clock frequency was 2 seconds and the contact pressure 150 N / m ² .

The printing was done as follows:

Position the product

Color photograph by tampon on cliche

Color output by tampon on the product

Remove product from the receptacle

As a result, a printed object having the desired quality, in particular acutance, of the printed image was obtained.

Example 2:

As example 1 with the following differences:

Commercially available chocolate kisses with a diameter of approx. 52 mm were used Pressure chamber temperature 10 ° C

Motif size 35 x 35 mm

• Product holder for chocolate kisses

• Viscosity: 60 s with Ford cup 4

Tampon with a hardness of 20 Shore 00 Si. This was previously heat treated (120 minutes at a temperature of 90 ° C)

Clock frequency 2.2 seconds

• Contact pressure 65 N / m ²

Claims

claims

1. Tampon printing process for printing on food with curved pressure-sensitive surfaces by means of a soft tampon and a suitable for pad printing ink

characterized in that

- as printing ink a fast-drying food coloring is used,

- The tampon a hardness of 60 to 20 Shore Si, preferably 40 to

Has 20 Shore Si and

- The printing process is performed within a time window of 1, 0 to 3.5 seconds.

2. pad printing method according to claim 1, characterized in that the tampon is exposed before use between 30 and 120 minutes of a heat treatment at a temperature of 60 to 100 ° C.

3. pad printing method according to claim 1, characterized in that the tampon is designed as a hollow tampon.

4. Pad printing method according to at least one of the above

Claims, characterized in that the tampon is pressed with a pressure of 70 to 160 N / m ² on the surface to be printed.

5. pad printing method according to at least one of the above

Claims, characterized in that it is the curved, pressure-sensitive surface is one of fruit or vegetables or optionally filled hollow body, in particular those made of chocolate.

6. Printing inks suitable for human consumption for printing on foodstuffs by pad printing with a content of (in parts by weight in each case)

20 to 40 shellac

30 to 70 polar organic solvents

6 to 40 dye

0 to 3 water

0.5 to 3 solubilizers

0 to 5 additives in total, 100 parts by weight result.

7. Printing ink according to claim 6, characterized in that the polar organic solvents are lower alcohols, in particular ethanol and n-butanol-1.

8. Printing ink according to claim 6 or 7, characterized in that the paint has a viscosity in the range of 50 to 80 s,

preferably 60 to 70 seconds as measured with a Ford cup # 4.

9. printing ink according to at least one of claims 6 to 8, characterized

characterized in that it is a white color with the following

Composition acts

24 to 28 shellac

35 to 40 ethanol

20 to 24 titanium dioxide

11 to 15 n-butanol-1

0.5 to 2 lecithin

in total, 100 parts by weight result.

10. Use of a printing ink according to any one of claims 6 to 9 in a method according to any one of claims 1 to 5.