HEAT TRANSFER PRESS FOR TRANSFERRING DECORATIONS

ONTO FABRICS

DESCRIPTION

Technical field

This invention relates to a heat transfer press that allows decorations to be applied on fabrics for example by using a transfer paper, by adding a fabric or vinyl, and/or by embossing.

Prior art

Various decoration techniques, including embroidery and printing, are known for the decoration of fabrics, clothes and, in general, any type of textile material.

As regards the embroidery decoration technique, the prior art includes multi-head industrial embroidery machines (with various embroidery heads) and single-head embroidery machines (specific multi-head embropidery machines which only comprise a single embroidery head). A multi-head industrial embroidery machine simultaneously embroiders fabrics (the term "fabric" is used hereinafter to refer to clothes, fabrics and, in general, all materials likely to be embroidered) that are individually disposed at each of the embroidery heads incorporated into the machine. The functioning of multi- head industrial embroidery machines is highly optimized in order to ensure that the output per time unit is as high as possible, while also ensuring that the quality of the resulting embroidery is as high as possible.

Each embroidery head in industrial embroidery machines usually presents a reception or loading area installed on the pantograph (a movement element common to all the embroidery heads) and provided with a quick holder to facilitate the loading and unloading of the fabrics, which are previously positioned on respective frames that hold them perimetrally and tighten them. The positioning of the fabrics on the frames is conducted by hand, normally on

a support table. The type of frame that is used depends on the size of the embroidery to be performed, the characteristics of the fabric and the type of embroidery machine, and for this reason there are many different types of frames. In addition, each embroidery head has one or more needles that collect thread from a series of thread reels and, with a movement synchronized with the pantograph, perform the embroidery on the fabric in accordance with a design pre-programmed by a software file stored in the machine.

There are also other fabric decoration techniques that are performed by a machine provided with two platens or flat surfaces, wherein at least one of said platens is heatable, so that in the process of performing said techniques the platens are pressed together, flattening the fabric that is positioned between them and applying a decoration onto the fabric. These decoration techniques will be hereinafter referred to as "transfer techniques". Examples of transfer techniques are the transfer of a transfer paper, the direct transfer of vinyls and flocks, and embossing. The machines that perform these transfer techniques are common on the market and are known as "heat transfer presses" or "heat seal presses". A single press, fitted with various tools, can perform all the aforementioned transfer techniques.

The transfer technique using a transfer paper involves positioning a piece of paper (called a "transfer paper") on the fabric, being the transfer paper provided with a decorative image printed with heat-sensitive ink that is to be transferred onto the fabric. When the platens are pressed onto the fabric, and the transfer paper and the fabric are flattened, and thanks to the temperature of at least one of the platens, the image printed initially on the transfer paper is transferred onto the fabric. The transfer paper can be printied using various techniques such as digital printing, silk-screen printing, laser printing, ink-jet printing and printing with sublimation inks.

The direct transfer of vinyls and flocks basically involves sticking a material (usually vinyl) directly onto the fabric, as a result of the pressure and temperature applied by the platens. The material is cut beforehand into the required shape and has had a thermal adhesive applied to it.

The process of embossing, which can be performed together with the transfer-paper technique or not, basically involves inserting the fabric between the platens of a metallic mould provided with an emboss or relief and then applying a pressure and temperature so that a permanent three-dimensional emboss is formed on the fabric in contact with said relief.

Due to aesthetic and cost-saving criteria, the concept of the combined use of various of the aforementioned techniques, namely the embroidery technique in combination with one or more transfer techniques, is now being introduced. For example, document US-20050160957-A1 refers to the combination of embroidery with other decorative techniques, where the embroidery is superimposed on a design applied by another decorative technique leaving at least part of said design visible. Nevertheless, with the machines currently available there is a drawback in the production process that prevents optimal utilization of the combined use of the embroidery and stamping techniques.

One such limitation is the impossibility of obtaining sufficient concordance between the embroidered pattern and the stamped design that the embroidered pattern is stitched upon. This limitation has several causes.

Usually, the fabric is transferred beforehand in a heat transfer press and then positioned on the embroidery frame (this is usually done on a support table by hand). A problem arises when centering the stamped fabric on the frame. Becasuse the fabrics are soft, shapeless and often elastic materials, and because the centering is done manually and the fabric must be tensely secured to the frame to guarantee correct embroidering, in practice it is almost impossible to achieve a perfect centering of the fabric on the frame.

In addition, once the stamped fabric is on the frame, said frame is positioned on the frame holder and pantograph of the embroidery machine. Embroidery machines have a manual centring system (or point "0" in relation to the frame) which is controlled by a keyboard that slowly moves the "0" point in X and Y. This keyboard is used by the machine operator before beginning to embroider, to try to adjust the concordance of the embroidery

over the stamped decoration. This process provides a relative concordance quality in single-head embroidery machines, although even here a misalignment occurs when positioning the fabric on the frame (caused by tightening and/or angular deviation). In the case of industrial multi-head embroidery machines, which embroider several fabrics at the same time, the pantograph performing the movement that generates the embroidery is common to all the heads. It is necessary, therefore, in order to obtain a correct concordance, that the stamped decorations on the fabrics positioned on the frame are identically positioned in relation to their respective frames. This requirement is impossible to fulfil at the moment. For this reason, in productions conducted in the manner described, in which stamped designs are combined with embroidered designs, designs are made in which the precise fitting of one technique over the other is not important, such as abstract or diffused designs, thereby significantly restricting the design possibilities.

It is evident, therefore, that there is a need to ensure that the combined stamping and embroidery process is run by machines designed to guarantee that their respective decorations are applied together in a concordant manner, thereby enabling the application of aesthetically complex decoration designs.

This need to achieve an optimal process combining various decorative processes is known not only in the field of stamping and embroidery, but also in other fields such as the combined embroidery and silk-screening process. Silk-screening is another fabric decoration technique, completely different to stamping, which involves applying an ink or paint on the fabric and including a screen acting as a mesh so that the paint, forced by a scraper that is moved along the screen, passes through said screen only in certain areas. This process is conducted color by color, and the paint of one color must be dried before applying the next color. As regards the combined use at industrial level of the silk-screening and embroidery techniques, the invention WO-2004058415-A1 is known and refers to a method and apparatus that enable the application on a fabric of a decorative element that combines a silk-screen design followed by an embroidered design, without releasing the fabric from a common frame. Specifically, the apparatus that the invention relates to is a specific frame that can be separated into different parts so that a series of parts assembled together

are suitable for a silk-screening machine, while another series of parts assembled together are suitable for an embroidery machine.

The present invention aims to provide the necessary means and methods to enable the creation of decorative elements on fabrics by means of a stamping process followed by an embroidery process or vice versa. Said means and methods make it easier to perform the combined stamping and embroidery process (already known in an unproductive form and with diffused designs, as has already been explained) in industrial volumes and production times, and with an increase in quality and aesthetic possibilities as it enables a perfect concordance of the embroidered ends with the stamped design.

Brief description of the invention

It is an object of this invention to provide a heat transfer press that enables stamping of various decorations and/or embosses onto a fabric situated on a standard frame used in fabric embroidery machines, in order to then remove said frame without releasing the fabric and position the frame directly on the conventional embroidery machine. In this way, as the frame is common to both machines (stamping and embroidery), a fabric initially positioned in the frame receives the transfer and then the embroidery or vice versa without shifts appearing between the stamped design and the embroidery. Furthermore, by using a single frame, the fabric can be transported from one machine to another simply and quickly, thereby reducing the total manufacturing time of the stamping and the embroidery.

Unlike document WO-2004058415-A1, the present invention does not require a frame of a particular design but, rather, proposes a design of a heat transfer press adapted to the conventional frames of embroidery machines. This results in lower costs and reduced complexity in executing the combined embroidery and stamping process.

The invention defines a heat transfer press, adapted in general terms to stamp on fabrics positioned on conventional embroidery frames. There are various construction forms of textile transfer machines/presses. The detailed

description of the invention given below focuses on a construction type known as a "press with a frontally-extractable second platen", although the invention is equally applicable to other construction forms such as machines/presses with several movable lateral platens, machines/presses with angular aperture of the top platen, machines/presses with an oscillating top platen and other variations all with platens capable of being closed upon themselves.

In general terms, the presses are designed with quick-change platens so they can be adapted with their various platen shapes to the different frames and needs that may be required of them in everyday embroidery.

The combined stamping and embroidery technique that can be performed industrially by the inventive heat transfer press and a conventional embroidery machine allows the opening up of a new range of fabric decoration design possibilities, reducing existing drawbacks. It enables the quality manufacture of this textile decoration combination very quickly and flexibly. It also enables two completely new processes in the industry: one is embroidery performed on an embossed fabric, and the other is stamping with sublimation inks on a design embroidered entirely with white polyester thread. Both processes are impossible to perform without the positioning precision afforded by the inventive machine. It also significantly reduces the amount of ends in the embroidery as it replaces certain embroidery areas with astamping, cutting production times in the process.

Brief description of the figures

Details of the invention can be seen in the accompanying non-limiting drawings:

- Figure 1 shows a view in perspective of an embodiment of the inventive machine.

- Figure 2 shows a view in section of the machine of Figure I ₅ according to a cross-section through A-A.

Detailed description of the invention

Figure 1 shows a perspective of an embodiment of the heat transfer press, adapted for the production, in industrial volumes and times, of fabrics with decorative elements in the form of a combination of stamping and embroidery. The heat transfer press (1) comprises a main body or stand (2), an first platen (3) and a second platen (4). The first platen (3) in this case is mobile and heatable (on other occasions the second platen (4) can be mobile and/or heatable), and presents a shape (7) adapted to that of a standard frame (8) but with a slightly smaller size and with sufficient free depth to avoid flattening areas external to the work surface, such as the frame brackets (15) or the frame lips (16). The first platen (3) is capable of being closed upon the second platen (4), and thanks to its shape (7) it is capable of passing through the frame (8) and pressing the fabric (5) so that when the first platen (3) is heated a decoration is transferred onto the fabric (5). In the case represented in the figure, the decoration is a transfer paper (6) or a vinyl.

Whereas in conventional heat transfer presses the fabric (5) is extended directly on the second platen (4), the heat transfer press (1) according to the invention comprises frame holders (9) for the rapid fitting of the frame (8). The fabric (5) positioned on the frame (8) is flush at the bottom as this is both a common characteristic and a common requirement for all known industrial embroidery machines. In this way, the conjunction of an first platen (3) adapted in shape and size to the frame (8) receiving it, and the fixed frame holders (9) for that frame (8), in this case positioned in a suspended way from the rear of the second platen (4), given that the second platen (4) is extractable in a forwards direction, enable the use of the heat transfer press (1) in the manner described.

In the case of the figure, the second platen (4) is installed on an extractable tray (17) that is lockable on _. both ends of its stroke and capable of withstanding the extreme pressures exerted on it by the first platen (3), being represented in a fully extracted position in relation to the stand (2). The fact that the second platen (4) is extractable facilitates the loading of the frame (8), the positioning of the transfer paper (6) or vinyl, and the unloading of the

frame (8). In this embodiment the frame holders (9) are attached to the second platen (4), and other different embodiments can exist such as, for example, arranging the fixed frame holders (9) in relation to the operating point of the platens (3, 4) or, what is the same, arranging the frame holders (9) in such a way that the frame (8) is situated in a fixed position towards which the platens (3, 4) close.

The specific embodiment of the frame holders (9) is, in this case, in the form of two elongated plates supported from the back of the second platen (4) and positioned one on either side of said second platen (4). In addition, as can clearly be seen in Figure 2, the frame holders (9) are situated at a certain distance (d) from the second platen (4) in order to allow sufficient height for the comfortable fitting of the frame (8) on the frame holders (9). When the first platen (3) descends, the flexion of the frame holders (9) and the flexion of the fabric (5) itself are sufficient to allow the fabric (5) to be pressed onto the second platen (4). In the case of the figure, the second platen (4), as in other known heat transfer presses, is designed with a single lower central support (18), thereby enabling the positioning of the fabrics (5) in an open manner, i.e., as if "dressing" the second platen (4) as shown in Figure 1, in the event that this were recommendable (for example, to transfer onto the back of an item of clothing, the back of said item of clothing remains on top of the second platen (4), whereas the front of the item of clothing remains beneath the second platen (4)).

Depending on the types of frames (8) that are used, the first platen (3), the second platen (4), the frame holders (9) of the frames (8) and/or the point fastening said frame holders (9) to the heat transfer press (1) could have to be replaced.

The heat transfer press (1) of the figure also can comprise at least one generator means (10) to enable the creation of at least one reference (11) on the fabric (5). Said references (11) act as a guide for situating the transfer paper (6) or vinyl on the fabric (5). Preferably, the generator means (10) is a light- emitting means that projects a point of light on the fabric (5), with said point of light acting as a reference (11). This transfer paper (6) or vinyl can be left loose

or be fixed to the fabric (5) by a temporary adhesive or any other temporary fixing means.

The process of stamping and embroidering using the heat transfer press (1) of Figure 1 and a conventional embroidery machine is basically the following:

a) The fabric (5) is positioned on the frame (8), and the frame (8) is connected to the frame holders (9), which are in an extracted position from the heat transfer press ( 1 ) .

b) When positioning transfer paper (6) or vinyl, it is positioned on the fabric (5), with the references (11) projected on the fabric (5) by the generator means (10) acting as a guide. In the case of the figure, the references (11) indicate the points on the fabric (5) at which the vertices (13) of the transfer paper (6) must be positioned.

c) The second platen (4) is pushed causing it to move in the direction of the arrow (12) until it is correctly situated beneath the first platen (3).

d) The first platen (3) descends hi the direction of the arrow (14) towards the second platen (4) and for a few seconds heat and pressure is applied on the transfer paper (6) and the fabric (5) so that the design carried by the transfer paper (6) is transferred onto the fabric (5).

e) The first platen (3) is raised up in the opposite direction to the arrow (14) and the second platen (4) is extracted in the opposite direction to the arrow (12).

f) The frame (8) is disconnected from the frame holders (9), and both the fabric (5) and the frame (8) are taken to the embroidery machine, provided with its own brackets suitable for receiving the frame (8). As multi-head embroidery machines can embroider various fabrics (5) simultaneously and in parallel to each other, it is necessary to

stamp various fabrics (5) beforehand, each one on a corresponding frame (8), and to then embroider all of them simultaneously.

The use of the heat transfer press (1) according to the invention presents several key advantages over a conventional heat transfer press with regard to the time and the difficulty of executing the process and the ability to conduct industrial production. First of all, in the case of using a conventional heat transfer press, the fabric (5) is positioned directly on the second platen (4) for the stamping phase, and at the end of the stamping it is positioned on a frame (8) for the embroidery phase. When using the inventive heat transfer press (1), however, a single initial fitting of the fabric (5) on the frame (8) is all that is necessary. Secondly, the use of a single frame (8) for the stamping and embroidery, without releasing the fabric (5), allows the position of the embroidery on the stamped decoration to be adjusted perfectly. Thirdly, the use of means (10) to generate references (11) allow that when various stamped fabrics (5) are generated, each one in its respective frame (8), for their application in parallel in the embroidery machine, the stamps on each fabric (5) are situated in an identical position in relation to their corresponding frame (8). In this way, when the frames (8) and the fabrics (5) are positioned in parallel on the embroidery machine, the movement between the embroidery and the stamped decoration is the same for all the fabrics (5), and it is therefore possible to calibrate the embroidery machine so that all the embroideries are adjusted correctly to their respective stamped decoration. In contrast, in the event that this process is performed without the inventive machine, after performing the stamp on the fabric (5), the position of the fabric (5) on the frame (8) has to be estimated, and after both (5, 8) have been positioned on the embroidery machine, it is the case that the stamped decoration on each fabric (5) presents a different deviation in relation to its frame (8), making it virtually impossible to calibrate the embroideries in order to prevent some of them being off-centered in relation to their stamped decorations.

Figure 2 shows a cross-section of the first platen (3), the second platen

(4) and other related elements, with the first platen (3) being closed on the second platen (4) in order to transfer the transfer paper (6) or vinyl, or to create the embossing or a combination of these techniques on the fabric (5). The

fabric (5) is attached to the frame (8), and the frame (8) is connected to the frame holders (9). The connection between the frame (8) and the frame holders (9) is formed by clips, tabs or any other mechanical or non-mechanical connection that is easy to connect and disconnect. Preferably, the same system as that used originally for the frame (8) in order to fix it to the embroidery machine is used. The first platen (4) presents a shape (7) with such dimensions that when it is closed on the second platen (4), it passes through the frame (8) and presses the fabric (5) and the second platen (4). This characteristic of the shape (7) of the first platen (3) enables the correct transfer of the transfer paper (6), vinyl, emboss or other decoration onto the fabric (5).