FR2745747A1 - PROCESSING MACHINE IN PARTICULAR FOR THE SERIGRAPHIC PRINTING OF A MEDIUM - Google Patents

Abstract

A processing machine, particularly for silk-screen printing on a fabric medium, including a supporting assembly (E); a roll (6) rotatably mounted on one side of the assembly for storing a material (7) in the form of a thin film of semi-rigid material; and means for moving the film (7) and transferring same onto a receiving roll (9) on the opposite side of the assembly (3) from the storage roll (6), in order to enable said film to be engaged by a tool (O) movably mounted on said assembly between the two rolls (6, 9).

Description

TREATMENT MACHINE IN PARTICULAR FOR
THE SERIGRAPHED PRINT OF A MEDIUM.

 The invention relates to the technical sector of screen printing of all types of supports but more particularly, all textile supports.

 According to the current state of the art, screen printing is generally carried out by means of flat or rotary frames, on which is stretched and fixed a polyester fabric for the flat frames and a metal film for the rotary frames. The polyester or other fabric is previously coated with a photosensitive resin to allow the etching of the design to be printed. The etching technique is always carried out by printing the photographic resin, for example by means of a laser. Generally, each frame corresponds to a color, so that to compose a drawing with several colors, the number of frames must correspond to the number of colors. When the frame is placed in contact with the fabric, a quantity of a specific color is poured into the frame to be transferred to the fabric under the mechanical action of a scraper which is shaped to push, under the effect of its translational movement, color through the mesh of polyester fabric or metal film.

 According to this technique, it is therefore necessary to have a number of frames equal to the number of colors that make up the drawing. Each frame is installed on the machine according to a sequence determined by being subject to means for being moved step by step along a support table on which the fabric to be printed is placed. Each time the color changes, the frame must be removed from the machine and washed. It is then necessary to install a new frame for printing a new color.

 Printing machines are also known which are shaped to receive a plurality of frames arranged in alignment, the fabric being displaced relative to these frames which each correspond to a color. This type of machine requires particularly large dimensions and represents a very high cost.

 It therefore appears, whatever the printing technique used, that it is carried out by means of independent frames each having a polyester fabric, a film or the like, treated to correspond to a specific color pattern of the drawing to be printed. . This results in significant manipulation corresponding to the repetitive positioning of the frames on the machine. For example, for a design of ten colors and eight variants, we must move eighty frames having an average weight of nine kilos, so that the operator is forced to move 720 kilos for the assembly and 720 kilos for the disassembly.

 In addition, these frames, the number of which is very large for the same design, represent a particularly large storage and transport volume. We also observe that the frames are relatively fragile and must be handled with the greatest care. Risks of twisting are not excluded. It is also impossible to reuse the same fabric or film for different prints. The installation of the frames on the machine also requires particularly meticulous adjustments.

 Other drawbacks also appear at the level of the doctor blade. The latter is mounted inside the frame with displacement capacity and exerts a certain pressure on the polyester or other film, in order to be able to transfer the color. Indeed, a predetermined quantity of color is poured inside the frame to be spread under the action of displacement of the scraper. It is understood that the amount of color placed in the frame is not precise since in most cases the latter is poured manually. This results in significant waste. In addition, the pressure exerted by the doctor blade is capable of generating deformations which can have a detrimental influence on the precision of the printing by also generating wear of the parts in contact by friction.

 The object of the invention is to remedy these drawbacks in a simple, safe, efficient and rational manner.

 The problem which the invention proposes to solve is to make a universal machine particularly suitable for screen printing of all textile supports with the aim of eliminating the multiplicity of printing frames and consequently the numerous drawbacks resulting therefrom.

To solve such a problem, a machine has been designed and developed which includes
- a support assembly
- a film storage roller in the form of a thin film of semi-rigid material, mounted with rotational drive capacity at one of the sides of the assembly;
- means for driving the film to transfer it to a receiving roller mounted on the assembly, opposite the storage roller, with a view to subjecting it to the action of a tool mounted on said assembly, with capacity displacement between the two rollers.

 To solve the problem of continuously treating the fabric, the support assembly is mounted with the ability to move in guided translation along a table receiving the fabric flat, the storage and transfer rollers being arranged parallel to the direction of displacement so that the tool moves transversely relative to said tissue.

 In the case of an application of the machine to the screen printing of a fabric or other support, the film is microperforated and is covered with a photosensitive resin or not, the tool being constituted by a doctor blade arranged to transfer a colored ink on the fabric through the microperforations of the film.

 To solve the problem of eliminating the number of frames corresponding to the number of colors and replacing these frames with continuous film, the latter consists of a plurality of distinct zones each corresponding to a color, each of said zones being separated by a neutral zone.

 Another important problem which the invention proposes to solve is to modify the design of the doctor blade and the very principle of depositing the color on the support.

 To solve this problem, the doctor blade acts as a reservoir and is connected to a pressurization system of the color ink to send it through a slit on the fabric to be printed, through the microperforated film.

 The fact of not pressing on the frame has the advantage of avoiding deformations which can have an influence on the precision of the impression, of having less wear on the parts in contact by friction, of being able to adjust the pressure of thrust on the color by increasing or decreasing the penetration on the fabric, and increasing the scraping speed.

 Advantageously, the doctor blade is connected to washing means in the form of containers, containing water, arranged to direct it inside the doctor blade.

 The color is contained in small containers that can be used for weighing. On these small containers is fixed, each time, a cover to which are connected an air inlet and a pipe which brings the color to the scraper. The air inlet is tangential to the wall of the tank, so as to allow, during the washing phase, to suck up the water by means of a venturi tube and push it tangentially on the internal wall by increasing the washing efficiency. After reaching a certain level, water passes through the pipe which brings the color to the doctor blade, thus washing the pipe and the internal part of said doctor blade and, when the film moves for the change of frame, also washing the film.

 Given the design of the doctor blade, the latter can also be applied in the case of a screen printing machine, in accordance with the cited and current state of the art. In this case, the doctor blade can be washed independently after dismantling it.

 To resolve the problem posed of ensuring that the film is entrained between the storage roller and the receiving roller, in order to successively subject each zone to the action of scraping, the film has laterally perforated tracks cooperating with toothed wheels. drive mounted near the receiving and storage roller in particular, as well as laterally to be guided over its entire length.

 To solve the problem of simplifying handling and easily equipping the machine according to the desired impression, each of the rollers is mounted in a removable cartridge and has temporary coupling arrangements with at least one geared motor for the drive. in synchronism and sequentially, said rollers.

 To solve the problem of reducing the weight of the support assembly, the latter is constituted by a carriage subject to drive means step by step along the table receiving the fabric, said drive means being integral with part of the table and connected to the carriage by means of transmission determined to subject the carriage to high acceleration.

In another embodiment, the carriage is fixed, the fabric, or other support to be screen printed, moving relative to said carriage,
The invention is set out below in more detail with the aid of the figures of the accompanying drawings in which
- Figure 1 is a plan view of the machine;
- Figure 2 is a front view corresponding to Figure 1;
- Figure 3 is a cross-sectional view along line 3-3 of Figure 2;
- Figure 4 is a larger scale of a partial cross-sectional view showing the drive of the film
- Figure 5 is, on a larger scale, a plan view of the carriage.

- Figure 6 is a longitudinal sectional view of the doctor blade
- Figure 7 is a cross-sectional view along line 7-7 of Figure 6;
- Figure 8 is a plan view of part of the nickel film;
- Figures 9, 10, 11, 12 and 13 are schematic plan and sectional views showing the operating principle of the machine according to the invention.

 As shown in Figure 1, the machine comprises a support frame (B) in the form of a table on which is placed the fabric (T) to be screen printed. On this table, is mounted with displacement capacity in guided translation, a support assembly (E). This assembly (E) constitutes a carriage (3) and is subject to motorized coupling means to be moved step by step along the table.

Advantageously, the movement of the assembly (E) is effected by means of a motor member (1) fixed on a part of the frame. This drive member (1) is connected by all known and appropriate transmission systems (2), of the belt type for example, to the assembly (E). The drive motor (1) being independent of the carriage (3), the latter benefits from a reduced weight and can be subjected to high accelerations, which is important for productivity.

 According to an important characteristic of the invention, the assembly (E), including the carriage (3), has the general shape of a frame whose lateral sides (3a) (3b), parallel to the direction of movement of said assembly, are arranged for the mounting, in a removable manner, of two support cartridges (4) and (5). The cartridge (4) receives a storage roller (6) on which a film (7) is wound in the form of a thin film of semi-rigid material. The roller (6) is slaved to a geared motor assembly (8) for its rotational drive.

 In contrast, the cartridge (5) receives a take-up roller (9) intended to receive the film (7) as it moves. The roller (9), in the same way as the roller (6), is slaved to a geared motor (10) to be driven in rotation. Note that the receiving roller (9) is not necessarily removable, the film (7) can be rewound in the storage roller (6). The geared motors (8) and (10) are driven simultaneously in a perfectly coordinated manner, thus avoiding exerting any tensile force on the film.

 Similarly, the geared motors (8) and (10) are subject to any electronic control circuit to be angularly driven, in synchronism, sequentially, according to a predetermined value corresponding to the desired advance of the film (7). Given the removable assembly, totally or partially, of each cartridge-roller assembly, each of said rollers (6) and (9) has temporary coupling arrangements with the corresponding geared motor (8) and (10).

 The film is entrained between the two rollers (6) and (9) for example by means of perforated tracks (7a) formed near the longitudinal edges of the film. These tracks cooperate with toothed wheels (17) and (18) arranged at the level of the cartridge (5) where the receiving roller (9) is mounted. Likewise, a toothing is arranged laterally at each of the sides of the carriage, to guide the film over the entire length. The wheels (17) and (18) are for example driven in rotation and in synchronism with the roller (9).

 Note also that only one of the rollers (6) or (9) can be motorized. In this case, the motorized roller is coupled to the other roller, by any known and suitable transmission system to cause, concomitantly, its rotational drive.

 The film (7) is previously etched by producing a plurality of distinct and continuous zones (7b). Each zone (7b) is constituted by a plurality of microperforations corresponding to a color of a desired pattern as will be described in the following description.

 The etching takes place after coating the film (7) with a photosensitive resin fixed by light or not which will be burnt by a laser.

The entire film (7) can be subjected to the action of a nickel bath.

It is not excluded to use a film in another material which is microperforated, depending on the type of design to be obtained. Each zone (7b) is separated by a neutral zone (7c). The length of the film has a number of zones (7b) in particular, corresponding to the number of colors in the design or pattern to be printed.

 It therefore appears that the patterns of different colors are produced on a continuous film capable of being stored in the form of a roll like a photographic film. The use of a plurality of distinct frames, each corresponding to a color according to the state of the art as described above, is therefore eliminated.

 The transverse edges (3c) and (3d) of the carriage (3) constitute parallel guide paths for mounting with the ability to move a tool (O). This tool (O) is moved transversely relative to the fabric while remaining parallel to the rollers (6) and (9). For example, the tool (O) is mounted in a support cooperating with a system of rollers with a profiled rail which has the guide tracks (3c) and (3d). The entire support is subject to a drive member to be moved between the rollers (6) and (9), in a back and forth movement.

 To carry out the screen printing operation as such, the tool (O) consists of a doctor blade (13). In this regard, according to another important characteristic of the invention, the doctor blade (13) acts as a reservoir (13a). The whole doctor blade (13) is connected to a system for pressurizing a color ink in order to send it by means of a continuous slot (13b) through the microperforated film (7), on the fabric to be to print. For example, the color can be contained in small containers (14) on which is fixed a cover to which are connected an air inlet (15) and a pipe (16) which brings the color inside the scraper ( 13). Note that the slot (13b) can be likened to a continuous line of microjets.

 The air intake takes place tangentially or substantially tangentially to the internal wall of the color reservoir to be transferred into the scraper. These arrangements are important for cleaning the doctor blade and the color container. Indeed, the doctor blade is connected to a water tank so that during the washing phase, the water is sucked in, from a pipe, by means of a venturi tube and pushed tangentially on the internal wall of the tank thus increasing washing efficiency. After reaching a certain level, the water passes through the colored supply pipe (16), thereby washing the said pipe and the internal part of the doctor blade. These arrangements also make it possible, as will be indicated in the following description, to wash the film (7) when the latter is wound up to a determined value on the take-up roller (9).

 Note that the doctor blade (13), taking into account its new and inventive specific characteristics, is not necessarily linked to the basic concept of the printing machine as defined. Indeed, the doctor blade (13) can completely be used in the case of a conventional screen printing using a plurality of independent frames.

 Obviously, all of the moving elements of the machine, in particular the support frame (3), the doctor blade (13), the storage (6) and reception (9) rollers, are subject to control electronics, allowing automatic operation, according to a preprogrammed cycle which depends on the design and type of fabric. This results in the following operation, with reference to FIGS. 9, 10, 11, 12.

 The film (7), corresponding to the different patterns to be printed, and consequently having a plurality of distinct and continuous zones (7b), is stored on the roller (6) which is placed in the corresponding cartridge (4). The film (7) is attached to the other receiving roller (9) by engaging the perforated tracks (7a) with the drive teeth (17) and (18). One of the zones (7b) is positioned, in a controlled manner, above the fabric (T), inside the frame (3), while the reserve zone (7c) which follows it is arranged close from one of the longitudinal edges of the fabric, outside the table, and from the side of the take-up roller (9).

 The chosen ink color is sent under pressure to the tank (13a) of the doctor blade (13). Obviously, the ink is sent under pressure by any known and appropriate means allowing the quantity and the flow of ink to be controlled. The doctor blade (13) is then moved along the transverse guide rails (3c) (3d) to deposit, concomitantly, a quantity of ink on the area in question (7b) of the film (7). The ink is sent under pressure through microperforations to correspondingly print the fabric (T).

 When the doctor blade (13) reaches the end of the zone (7b), that is to say just before the zone (7c), the latter is automatically returned or not to the initial position, depending on the printing cycle. During this return movement, the arrival of the ink may or may not be interrupted. The entire carriage (3) is then moved laterally one step relative to the frame of the support table with a view to printing the same area considered (7b) on an adjacent part of the fabric.

 The doctor blade is then moved as previously indicated to inject the ink under pressure through the microperforations of the film.

These operations, which are carried out in a fully automatic manner, are repeated until the entire carriage (3) reaches the end of the fabric.

 At this stage, a plurality of zones (7b) corresponding to one of the selected colors have therefore been printed on the fabric (T). The doctor blade (13) is then temporarily positioned at the neutral zone (7c) for cleaning. As indicated, the doctor blade is therefore connected to a tank sending water under pressure. Air is sent tangentially to the internal wall of the reservoir (13a) to allow, during this washing phase, to suck up the water by means of the venturi tube and to push it tangentially on said internal wall to increase the efficiency of the washing. When a certain level of water is reached, the water passes through the pipe (16) which brings the color to the doctor blade (13), thus washing said pipe and the lower part of the doctor blade.

 The film (7) is wound up by a determined length on the roller (9) to position a new area (7b) on the fabric (T). This winding has the effect of subjecting the area (7b) of the film having received, in the preceding step, the color, to the action of the scraper to cause in a concomitant manner the cleaning of the film as and when its winding. This operation is carried out during the return of the entire carriage (3) to the initial position. The doctor blade then receives a new color.

 This cycle is repeated until the film (7) is transferred in whole or not, depending on the type of use, on the take-up roller (9) corresponding to the successive and continuous positioning of the different zones (7b) of the patterns to be to print.

 In view of these constructive arrangements, the machine according to the invention can also be applied to carry out the etching of the different zones (7b). It suffices to replace the doctor blade (13) with another tool of the appropriate type, such as for example a laser. As before, the film is transferred step by step from the roller (6) to the roller (9).

The advantages are apparent from the description, in particular it is emphasized and recalled
- the production of the different areas to be printed in the form of a continuous film, avoiding the use of an independent number of frames corresponding to each of these areas
- the packaging of the film in the form of a roll that can be packaged in cartridges allowing a noticeable gain in space for storage;
- the emitting roller, the cartridge and the film can constitute an inseparable whole;
- the number of manipulations reduced since only one manipulation is carried out regardless of the number of colors and variants;
- minor risks of breakage during the various manipulations;
- non-deformability over time;
- the possibility of re-engraving the same film several times when the latter receives a nickel film;
- the theoretically unlimited duration of the film;
- the significant reduction in the waste of color ink;
- the reduction in water consumption for cleaning the various screen printing elements;
- the elimination of the pre-setting of the frames;
- the abolition of trials with talc;
- higher scraping speed;
- the greater penetration of the color which is sent under pressure to the scraper tank without the latter exerting a pressure force on the film
- elimination of the time necessary for the different changes of frames;
- possibility of having more drawings on the same cartridges
- increase in productivity.

 From the construction point of view, the support table constitutes a rigid surface and is provided laterally with a chute (19) of adequate depth to contain the water withdrawn from the carriage (3) by means of a tube or breather during movement and a continuous waste water discharge chute. These provisions allow, as indicated, the washing of the doctor blade (13) and of the zone considered of the film, during the vacuum return of the whole of the carriage.

 Finally, it is emphasized that this machine makes it possible, by construction, to carry out other operations annexed to the screen printing, such as for example the engraving of the film, its washing ... It suffices for this to equip the assembly ( E), in particular the carriage (3) of the corresponding appropriate tool.

Claims (13)

 1 / Processing machine in particular for the screen printing of a textile support, characterized in that it comprises  - a support assembly (E);  - a storage roller (6) of a film (7) in the form of a thin film of semi-rigid material, mounted with rotational drive capacity at one of the sides of the assembly;  - drive means (17) (18) of the film (7) to transfer it to a receiving roller (9) mounted on the assembly (3), opposite the storage roller (6), in view to subject it to the action of a tool (O) mounted on said assembly, with the ability to move between the two rollers (6) (9).  2 / processing machine according to claim 1, characterized in that the support assembly (E) or the textile support (T) are mounted with relative displacement capacity guided, the storage rollers (6) and transfer (9) being arranged parallel to the direction of movement so that the tool (O) moves transversely relative to said support.  3 / Treatment machine according to claim 1, characterized in that the film (7) is microperforated and can be subjected to a nickel-plating treatment, being covered with a photosensitive resin or not.  4 / Treatment machine according to claim 2, characterized in that the tool (O) consists of a doctor blade (13) arranged to deposit a colored ink which will be transferred under the action of said doctor blade on the fabric, at through microperforations of the film (7).  5 / A processing machine according to claim 4, characterized in that the doctor blade (13) acts as a reservoir (13a) and is connected to a pressurization system of the color ink to send it through a continuous slit calibrated on the fabric through the microperforated film.  6 / Treatment machine according to claim 5, characterized in that the doctor blade (13) is connected to washing means in the form of containers containing water, arranged to direct it inside the doctor blade.  7 / treatment machine according to claim 6, characterized in that the color is contained in containers which can be used for weighing and on which is fixed a cover to which are connected an air inlet and a pipe which brings the color to the doctor blade, the air inlet being tangential to the wall of the tank, so as to allow, during the washing phase, to suck up the water by means of a venturi tube and push it tangentially on the internal wall in increasing the efficiency of washing.  8 / processing machine according to claim 3, characterized in that the microperforated film (7) consists of a plurality of distinct zones (7b) each corresponding to a pattern, each pattern zone being separated by a neutral zone (7a ).  9 / treatment machine according to any one of claims 1 and 2, characterized in that the film (7) has laterally perforated tracks (7a) cooperating with a system of toothed drive and lateral guide (17) and (18).  10 / processing machine according to claim 9, characterized in that each of the rollers (6) and (9) is mounted in a cartridge (4) and (4) removable and has temporary coupling arrangements, with at least one drive reduction motor.  11 / Treatment machine according to claim 1, characterized in that the support assembly (E) is constituted by a carriage subject to drive means step by step along a table receiving the textile support, said means d drive being integral with a part of the table and connected to the carriage by means of transmission determined to subject the carriage to high acceleration.  12 / A processing machine according to claim 1, characterized in that the support assembly (E) is constituted by a carriage which is fixed, the textile support being mounted on a table with capacity for movement relative to said carriage.  13 / A processing machine according to claim 1, characterized in that the tool (O) consists of an assembly in the form of a laser capable of ensuring a plurality of microperforations in the thickness of the film.