TW202014309A - Direct to mesh screen stencil creation - Google Patents

Abstract

A direct to mesh (DtM) screen printer for creating a screen stencil is provided. The DtM screen printer includes a frame to hold a pre-stretched mesh in place during application of a jettable emulsion, a fixture to hold the frame, a platen to hold a release fluid against one side of the pre-stretched mesh, a fluid dispenser for dispensing the release fluid onto the platen or mesh, and a printer carriage supporting a print head for printing the jettable emulsion on a side of the pre-stretched mesh opposite the platen. A process is also provided, the process being for using the DtM screen printer to prepare the screen stencil for screen printing.

Description

Direct screen template creation

Screen printing is a printing technique in which a screen is used to transfer ink to a substrate, but a screen printing template (also called a masking template) makes it impermeable to areas other than ink. A blade or scraper moves across the screen to fill the open mesh aperture with ink, and then a reverse stroke causes the screen to instantly touch the substrate along a contact line. This causes the ink to wet the substrate and is pulled out of the mesh aperture as the screen springs back after the blade has passed.

The establishment of a screen printing template is a tedious and labor-intensive task. It requires several procedural steps, chemical products, large amounts of water and is mainly manual. It is the smallest automated part of the current screen printing business.

Cross-reference of related applications

This application claims the priority of application No. PCT/EP2017/050214 filed on January 5, 2017.

There are several examples of previous solutions for directly coating a mesh to form a template for screen printing. These examples are now described. Mesh preparation and coating:

Direct emulsion application: This can be done with a machine or manually. Both sides of the screen must be coated with emulsion to ensure proper coverage. The machine or automation version is strictly a machine that replaces a human. The machine can apply the precise amount of emulsion more accurately and obtain even coverage. The machine usually has less waste.

Capillary membrane: These are membranes pre-coated with an emulsion. The mesh is supersaturated with water and the membrane (with the emulsion side down) is placed against the supersaturated mesh. Capillary action draws the emulsion into the mesh. This provides a more accurate emulsion coating on both thickness and coverage. Once the emulsion has diffused into the mesh, the film is peeled off.

Once the screen mesh is emulsified, the screen mesh must be dried. Once dry, it is ready for image transfer or template making. As the emulsion dries, it shrinks and conforms to the mesh, resulting in a rough, uneven surface. (This rough surface causes accelerated aging of the squeegee during the printing process.)

Today, most emulsions are activated by ultraviolet (UV) radiation (ie, UV activation), but can also be activated by visible light. Once coated, the template must be protected from any light exposure (even ordinary visible light has enough UV to start the curing process). In the following, it is assumed that the emulsion is UV activated/cured. Image transfer/template production:

In screen printing, there is a template for each color (usually cyan, magenta, yellow, and black (CMYK)), and there is a template for each spot color (a spot color is based on discrete colors, usually Colors that may not be easily achieved with CYMK colors). The areas of the template (one of which does not want ink to pass through) are blocked by an emulsion, which is then cured to form a template; all other areas have only meshes. Any openings in the mesh can be completely blocked or partially blocked by the emulsion to form a template.

Positive ink: Print a black, UV-absorbing layer onto a transparent plastic sheet. It is usually printed by a laser or inkjet printer with special positive ink (positive ink means a high opacity black ink that completely blocks all visible light and UV light). The film was then attached to the pre-coated mesh and exposed to UV light. The attachment is usually made by a removable tape, such as masking tape. Once exposed, the film is removed and the uncured emulsion is washed away.

However, this method is very labor intensive at all stages and it is impossible to automate many steps. In addition, this method is prone to errors, such as during the installation of the film, during the use of the correct film, and during the adjustment of the final template before printing. A lot of chemicals and cleaning agents and a lot of consumables (ink, film) are required.

Heat screen: In this method, the mesh is pre-coated with a heat activated emulsion. Typically, the mesh (without a frame) is placed in a thermal printer, where the emulsion is directly cured/activated. Once completed, the unexposed emulsion is washed away, the template is mounted on a frame and printed.

However, this method suffers from a limited number of meshes. Furthermore, the lotion is not so robust. The pre-treated mesh is expensive. The template alignment system is denser. Finally, the template may be damaged when it is installed.

Computer-to-plate (CtS) printing: In this method, a high-opacity black ink is used to print the coated mesh directly onto the emulsifying screen. This is similar to positive ink without a film. All programs are the same.

However, these machines require a high opacity ink, which is more expensive than ordinary inkjet inks.

CtS-wax: This method is a close relative of CtS-printing, but uses wax to block UV light. All other departments are the same.

However, due to the use of molten wax, these machines may be temperamental. In addition, these machines need to heat the wax to apply it to the mesh.

CtS-direct exposure: This technology uses a UV laser to directly expose the emulsion.

However, the machines used in this technology are usually very expensive. In addition, this program does not work on coarse meshes. Finally, UV lasers are still very expensive when they need to be replaced.

Each of the above methods requires some post-processing/follow-up. Except for thermal activation and direct CtS exposure, all stencils must be exposed (film or CtS printing and wax) after application of image occlusion. This program takes about 1 to 2 minutes per screen using a strong developer.

All screens must be washed out of excess emulsion. Care must be taken so that the emulsion does not enter the drainage system. The screen must be dried after cleaning.

For the membrane and thermal activation methods, the finished template must be fine-tuned when placed on the turntable to ensure proper registration. Current disclosure:

It is clear from the foregoing description of the current technology that a simpler method using less chemicals and less water is desired.

As disclosed and claimed herein and in accordance with the teachings herein, a direct mesh (DtM) method for forming a template involves the direct application and activation/exposure of an emulsion onto a screen using inkjet technology. Specifically and according to the teachings in this article, a DtM printer includes: A frame for holding a pre-stretched mesh in place during the application of a sprayable emulsion; A fixture for holding the frame; A pressure plate for holding a release fluid against one side of the pre-stretched mesh; A fluid dispenser for dispensing the release fluid onto the platen or mesh; and A printing press carriage that supports a printing head to print the sprayable emulsion on the side of the pre-stretched mesh opposite the platen.

FIG. 1 depicts a block diagram of a direct screen (DtM) printer 100. The DtM printer 100 includes a mesh support system 110 that includes a pre-stretched mesh 112 held in place by a frame 114. Then, the frame 114 is held by the clamp 116. The clamp 116 holds the frame 114 and the pre-stretched mesh 112 firmly and firmly in place during the application of the sprayable emulsion.

As used herein, the mesh 112 is made of connected bundles of textiles, fibers, metal, or other flexible/ductile materials, where it is woven in a cross-shaped pattern. The material constituting the mesh may be several textiles (silk, polyester); metal, such as stainless steel; or plastic, such as polypropylene, polyethylene, nylon, polyvinyl chloride (PVC) or polytetrafluoroethylene (PTFE); or glass fiber Any of them. The diameter of the beam can be any diameter common in screen printing, and the mesh size can also be any size common in screen printing. The coarser mesh is usually woven with larger diameter (specification) bundles, which requires a thicker emulsion coating.

The DtM printer 100 further includes a platen support system 120, including a release fluid 122 held by a platen 124 against the underside of the pre-stretched mesh 112. The pressure plate 124 provides a smooth flat surface for the release fluid 122 held firmly against the bottom of the pre-stretched mesh 112. The pressure plate 124 is configured to be as smooth as possible, impermeable to fluids, and resistant to dents and cracks. The pressure plate 124 can also be used to dissipate energy from a UV curing source 208 (not shown in FIG. 1, but shown in FIG. 2D).

Prior to applying the sprayable emulsion, once the release fluid 122 is in place above the platen, the release fluid 122 can be applied directly (eg, sprayed or wiped or brushed) onto the platen 124 or onto the mesh 112. For example, one fluid dispenser 126 for introducing or dispensing release fluid 122 onto platen 124 may include one or more sprayers 126. The sprayer(s) 126 may be an ordinary atomizer or other spray-type elements.

The release fluid 122 suppresses dot expansion by not reacting with the cured emulsion, which is the effect of a printing fluid extending into a printing medium. It is only necessary to suppress the point expansion in a short period because the curing system occurs very quickly after spraying the emulsion fluid.

Finally, the DtM printer 100 includes an inkjet printer 130 that includes a print head 132 mounted on a printer carriage 134. The print head 132 is configured to print the sprayable emulsion on the side of the pre-stretched mesh 112 opposite the platen 124. The printer carriage 134 is a high-precision printer carriage that is accurate in both the X and Y Cartesian directions to support accurate droplet placement in one or more passes while accumulating sprayable emulsion. In fact, the emulsion can be "accumulated" to fit a wide range of mesh specifications, from extremely fine to super coarse. Layering can be used to maintain high resolution as the emulsion is accumulated.

The print head 132 may be an inkjet printhead, such as a thermal inkjet printhead, a piezoelectric inkjet printhead, a drop-on-demand inkjet printhead, or other suitable materials capable of ejecting fluids (including the ejectable emulsion disclosed herein) Jet print head.

The screen mesh 112 (which can be of any type, even quite expensive or cheap and of any size) is stretched onto the frame 114. The frame 114 is placed into the inkjet printer 130 where the release fluid 122 has been placed on the platen 124. The jettable emulsion is then applied to the shadowed area by the inkjet printer 130 and exposed to high intensity UV lamps or other suitable UV sources such as UV light emitting diodes (LEDs) at substantially the same time. The wavelength of the UV lamp (or LED) can be tuned to the reaction range of the sprayable emulsion to obtain the best performance. For the sprayable emulsion disclosed herein, the emulsion reacts at a wavelength of 395 nanometers (nm). Other sprayable emulsions can have other reaction wavelengths, including below 395 nm. For coarse meshes, the coating can be done in multiple passes in order to accumulate the necessary emulsion thickness. "Coarse mesh" means having a loosely woven mesh, and therefore having a gap between the bundles greater than a fine mesh. For example, 335 meshes are considered to be fine meshes, while 110 meshes are considered to be coarse meshes, where the mesh number is the number of lines crossed per square inch.

With the recently developed low-viscosity sprayable emulsion, the direct mesh procedure disclosed in this article becomes possible. "Low viscosity" means a range from about 4 centipoise (cP) to about 15 cP (about 4 millipascals to about 15 millipascals). These new sprayable emulsions are used to create an embossing effect on various materials using UV printers. These new sprayable emulsions are also more elastic, so they can be more easily used as a replacement for previous emulsions. Any color can be used for sprayable emulsions (including transparent or clear), although light cyan or light magenta can be used to provide a slight contrast to verify the template.

One example of a sprayable emulsion that can be applied to one of the procedures disclosed herein is one of the UV-activated acrylate monomers that has elastomeric quality after curing. Sprayable emulsion is a special embossed "varnish" polymer that quickly cures to a highly durable/resistant layer that quickly accumulates on the substrate. Cured polymers are also durable and flexible/elastic (if they are rigid, they are easily broken during use and make the template useless). VersaUV (Roland DG) technology is an example of material that can be used to practice one of the teachings in this article.

The release fluid 122 is configured to provide a smooth, non-reactive printing surface under the mesh 112. It is also used to limit the dot expansion of printing emulsions. Spot expansion occurs when a jetted droplet (or spot) expands or spreads before UV exposure. This is particularly important when halftones are used, that is, the entire space is filled with lotion if not enough in the mesh. However, it is only necessary to suppress the point expansion within a short period, because UV curing occurs very quickly after spraying the emulsion.

The release fluid 122 is a fluid that expands the management point and does not react with the cured emulsion so that it does not lift or separate the emulsion from the mesh 112. By changing specific characteristics (including but not limited to changing surface tension, ionic mixtures, polar or non-polar components, or whether the fluid is aqueous or non-aqueous), the sprayable emulsion can be modified or customized for releasing fluid 122 fluid.

The release fluid 122 may be water-based (eg, distilled water), only water or with at least one sufficient amount of emulsifier to prevent evaporation of the release fluid. Examples of emulsifiers along with one type of emulsifiers known as surfactants include, but are not limited to, polysorbate, glycerin, and ethylene glycol, such as butylcellulose. In some embodiments, the (several) emulsifier may be present in an amount of at least 3 vol% to 5 vol% to prevent evaporation of the release fluid 122. Further examples of the release fluid 122 include water-based varnishes such as butyl acetate, xylene, mixed xylene, xylylene, and combinations thereof.

After placing the mesh onto the platen 124, the release fluid 122 is deposited directly onto the platen 124 or onto the mesh 112. In most preparations of current technology, the emulsion can be quite coarse; this is usually caused by the emulsion conforming to the mesh during the drying process. The rough emulsion surface may be worn at the scraper, so the surface of the scraper needs to be reformed or replaced. However, in a direct mesh procedure, when the sprayable emulsion accumulates in the mesh, the release fluid 122 ensures a very smooth surface; see, for example, FIG. 3B and its associated discussion.

Since the only emulsion applied to the mesh 112 is in a shielded area, there is no overshoot or overexposure in the UV light reflected into the shielded area. This provides a smoother and clearer image. (These overshoot and overexposed areas may create spots or depressions inside the image, especially around the edges. These are the "reverses" of pinholes.)

The pressure plate 124 provides a smooth, hard, impermeable surface for the release fluid 122, and gently pushes and tightens the mesh 112 to ensure that one of the emulsions to be applied is a good uniform, flat surface. In some embodiments, the pressure plate 124 does not absorb or chemically or physically release the release fluid 122 and is planar (±0.05 mm/meter). "Smooth" means that the surface of the pressure plate 124 may be a regular surface of polishing/gloss or matte/matte, as long as the surface is regular.

Example steps of the direct mesh procedure are depicted in FIGS. 2A to 2E as cross-sectional views of the DtM device.

In FIG. 2A, the frame 114 surrounds the pressure plate 124. The clamp 116 for supporting the frame 114 is omitted in this figure and FIGS. 2B to 2E. The frame clamp 116 is similar to the frame clamp currently used in this technology. One or more elements or sprayers 126 spray a layer of release fluid 122 on one of the top surfaces 124a of the platen 124. The sprayer(s) 126 may be fixed in place or configured to span the pressure plate 124. It will be appreciated that the release fluid can be applied in several different ways: for example wiping, brushing and the like, and spraying.

In FIG. 2B, a mesh 112 is placed across the top of the frame 114. Below the mesh 112 is a pressure plate 124, which has a thin, uniform coating of the released fluid 122 supported on the surface 124a of the pressure plate. In some embodiments, the thickness of the release fluid 122 is about 20 micrometers (μm), but is anyway smaller than the mesh specification and within ±0.5 μm flatness. The release fluid 122 supports the mesh 112 as it is applied to provide good coverage of the sprayable emulsion. The release fluid 122 is formulated to avoid adhesion of the sprayable emulsion to the platen 124. The release fluid 122 is formulated to prevent the emulsion from sticking, reacting, or otherwise adhering to the platen. In some cases, the emulsion may react with the release fluid 122, but the interaction/reaction may generally not allow any adhesion to the platen 124. If the adhesion to the pressing plate 124 is greater than the adhesion to the mesh 112, the emulsion can be debonded/delaminated from the mesh. This may cause pinholes or bare patches. In the worst case, it may cause the mesh to be damaged or torn.

In FIG. 2C, the pressure plate 124 with the release fluid 122 is moved up to the mesh 112, thereby tightening the mesh and pressing the release fluid against the back of the mesh. This provides a smooth, tensioned, horizontal surface for printing. The movement of the pressure plate 124 is indicated by the arrow 202.

In FIG. 2D, the printing head 132, which can be translated by the printer carriage 134 (not shown in FIG. 2D but shown in FIG. 1), directly prints the obscured image or template 206 (seen in FIG. 2E) onto the mesh 112, wherein The occlusion image is the inverted or negative image of the actual image to be printed or screen printed onto a suitable printing medium. The printing head 132 moves laterally in the direction indicated by arrow 204 to form a screen template 206 on the mesh 112. "Ink" is a UV-curable sprayable emulsion described above that is substantially UV-cured as it is applied by a UV source 208. In one example, the UV source moves laterally in the direction indicated by arrow 210. This is similar to what happens in a conventional UV printer. FIG. 2D depicts the print head 132 and UV source 208 moving across the mesh 112. However, the mesh support system including mesh 112 and frame 114 (and clamp 116) can translate relative to print head 132 and UV source 208. The UV source 208 can be fitted to both sides of the print head 132 to facilitate bidirectional printing of the mesh 112.

In FIG. 2E, the resulting template 206 is shown. The template 206 can be removed from the printing press and used immediately without any further preparation or processing.

In some embodiments, a layer 128 may be placed on the surface 124a of the pressure plate 124 before the release fluid 122 is applied to the surface 124a of the pressure plate 124. Layer 128 is referred to herein as the "background type." The platen 124 is maintained at a constant height and then the "background" 128 is placed on the platen 124. Examples of background type 128 include a 4 mm mirror, 2 mm clear glass, 2X glass (top), white polyethylene, glass (top)/mirror (bottom), 4 mm glass (top), and 3 mm mirror. Therefore, if, for example, a 4 mm mirror is used, the printed surface is 2 mm higher than 2 mm transparent glass. Sometimes, a "two-component" background is used to obtain different results. For example, "2X glass" consists of two transparent glass sheets, "glass (top)/mirror (bottom) is a 2 mm glass sheet on a 2 mm/4 mm mirror. Without following any specific theory, It is believed that two plates are used to introduce some light reflection/refraction, where the two surfaces intersect in the middle. "White polyethylene" is a white polyethylene sheet.

A comparison of results according to an example is shown in FIGS. 3A to 3B. The two figures show an emulsion applied to the mesh 112.

In FIG. 3A, in a conventional combination 300 of dispersible emulsion 302 and mesh 112, it is seen that the emulsion conformally follows the warp and weft of the mesh (bundles 112a and 112b), including both the top of the mesh and the bottom of the mesh . This shape retention occurs when the dispersible emulsion 302 is air-dried onto the mesh 112. Specifically, FIG. 3A shows how the emulsion 302 applied in a conventional manner shrinks as it dries onto the mesh 112 after being applied manually or with a coater. As the water component dries, this shrinkage is inevitable. Emulsion 302 is an emulsion commonly used in this technology.

In FIG. 3B, in the combination 350 of the sprayable emulsion 302' and the mesh 112 of the present teachings, it is seen that the sprayable emulsion has a flat bottom surface provided by the smooth surface 124a of the pressure plate 124 (and the release fluid 122 thereon) 302'a. It is seen that the top surface 302'b of the sprayable emulsion 302' is less conformal than the current emulsion 302 to the warp and weft of the mesh 112. (The bottom surface 302'a is where the screen ink will be applied and pressed through using a squeegee during the actual screen printing process.) Regarding DtM, since the mesh 112 has a release fluid 122 supported by a smooth platen 124, the emulsion 302 The'lower side 302'a is closer to flat or flat. This is also a result of substantially immediate curing by UV radiation.

This procedure is called direct mesh (DtM) to distinguish it from CtS (computer-to-plate), which requires additional processing before (ie, applying emulsion) and after (washing out unexposed emulsion and ink). In the DtM process, no additional processing before and after the sprayable emulsion 302' is applied, thus simplifying the template 206 creation.

FIG. 4 depicts a flowchart of an exemplary DtM process 400 for preparing a template for screen printing according to the disclosure herein. In the DtM program 400, a direct screen printer 100 is provided 405. As described above, the DtM printer 100 includes a fixture 116 for holding a frame 114 that is configured to hold the pre-stretched mesh 112 in place during the application of the sprayable emulsion 302'. The platen 124 of the DtM printer 100 is used to keep the release fluid 122 against one side of the pre-stretched mesh 112. Finally, the DtM printer 100 includes a printer carriage 134 that supports the print head 132 to print the jettable emulsion 302' on the side of the pre-stretched mesh 112 opposite the platen 124.

The DtM program 400 continues to place 410 the frame 114 in the fixture 116. The fixture 116 is part of the DtM printer 100 and is suitable for receiving various frame 114 sizes. The clamp 116 is configured to accurately fix the frame 114 in place so that the printer carriage 134 is accurately registered to the mesh 112.

The DtM process 400 continues to apply 415 the release fluid 122 to the platen 124 directly or through the mesh 112. When applied directly to the mesh 112, the application release fluid 122 may be as effective as when pre-applied to the platen 124. This can be important for very large templates or very high point densities (such as 5,000 DPI), where even if a good emulsifier is used, the release fluid 122 may still have time to evaporate.

In any case, the pressure plate 124 coated with the release fluid 122 is brought into contact with the mesh 112 (or the pressure plate 124 is brought into contact with the mesh 112 and the release fluid 122 is applied to the mesh). In some embodiments, the pressure plate 124 can be raised to about 1 millimeter (mm) to about 2 mm above the height of the mesh to provide a tightness to the mesh 112.

The DtM process 400 continues to apply 420 the sprayable emulsion 302' to the mesh 112. As described above, the jettable emulsion 302' is applied to the mesh 112 by the inkjet printer 130, wherein the inkjet print head 132 is used to jet the jettable emulsion.

The DtM procedure 400 ends with the UV radiation curing 425 jettable emulsion 302'. Any common UV source can be used to cure the sprayable emulsion 302'.

At the end of the DtM process 400, the template 206 is formed and cured, and is ready to be used to print color screens onto a suitable printing surface, such as, for example, clothing. In particular, the cured emulsion can be sprayed to form a screen template, wherein the opening in the screen template will be used to print an image on the printing surface. Examples

Perform four series of examples. In the examples and tables, the following definitions are now provided.

"Mesh resolution" refers to the number of lines per centimeter (cm). The mesh resolution may contain a letter indicating the diameter of the line, such as S (small diameter), T (medium diameter), or HD (large diameter). For example, "43T" is a mesh with 43 medium diameter wires per centimeter.

"Frame type" indicates the type of frame 114 used, and may be a one-roll frame, aluminum, or a large-roll frame. The "aluminum" frame is a fixed square metal aluminum frame in which the mesh is glued with a specific tension before starting. One of the typical values of tension is about 26 Newtons (N). The "roller frame" is a re-tensionable frame that allows one to change the tension of the mesh after the template is stretched. The roller frame is much more expensive than a standard square frame, but it is easier to maintain the correct tension and re-stretch. The large roller frame is slightly larger than the roller frame.

The metal mesh is a stainless steel, nickel-plated mesh. This type of mesh is often used for rotating screens or for screens from the same template that are exposed to corrosive fluids or used for a long time (many printing/pressing).

"Unit resolution" is the dot density interweave (DPI) ejected from the print head.

"Number of pulses" refers to the number of firing pulses sent to a particular nozzle.

The print head used has 8 nozzle rows. The heading "ink channel" refers to the number of rows used to eject fluid. "All" means all 8 columns. The symbol "11100111" indicates that the middle two columns have not been fired; this gives the effect of a "gap" between the jets.

"UV %" refers to the intensity of the UV radiation emitted by the adjustable UV LED source 208. A PMW (Pulse Width Modulator) is used to modulate the intensity of the UV LED source 208 to control the intensity of the generated UV light. The maximum value of the UV source 208 used is 100 W/cm ² . For example, a mark of 60% means that 60% of the UV light is modulated to 60% of full intensity.

"Release fluid" refers to the composition of release fluid 122 applied to platen 124.

"Background type" refers to what is used on the surface of the platen 124. The platen 124 is maintained at a constant height and then the "background" is placed on top of the platen. Examples of background types include a 4 mm mirror, 2 mm transparent glass, 2X glass (two 2 mm transparent glass sheets), "glass (top)/mirror (bottom)" (2 mm on a 2 mm/4 mm mirror Transparent glass) and "white polyethylene" (white polyethylene sheet).

"TEM" refers to the total emulsion measurement and is a measure of the thickness of the emulsion. Usually, a number of EoM (Emulsion on Mesh) is used, but this is the ratio of emulsion thickness divided by mesh thickness. Here, the number in μm refers to the total thickness, including the thickness of the emulsion plus the thickness of the mesh.

"Smoothness" refers to the smoothness of the template. On the platen side, the surface touch is extremely smooth without discernable roughness. On the printing side, the surface should be smooth to the touch. Slight roughness (similar to that experienced by frosted glass) is considered "acceptable". In the test results considered "unacceptable", the surface usually looks like sandpaper.

The smoothness results are based on a subjective assessment, where 1 is acceptable, 2 is slightly acceptable, 3 is slightly unacceptable, and 4 is unacceptable.

"Result" refers to one of the subjective assessments of the overall results of the experiment. The same subjective rating scale described for smoothness is also used here.

"A4 printing time" refers to the time it takes to print a screen with a size of A4 media (21.0 cm x 29.7 cm). Example Series 1

In Example Series 1, six experiments were conducted; details are provided in the following tables IA (test parameters) and IB (results). All experiments used UV Super Flex 100 ink as a sprayable emulsion, which is an experimental ink. The mesh color in each case is white. Frame types are differently one-roller frames, aluminum or one-roller frames, as listed in Table IA. The unit resolution in each case is 1440 DPI. The printing speed in each case is 300 cm/sec. The number of pulses is as described in Table IA. In the first 4 experiments, all 8 ink channels were fired, while in the last 2 experiments, the two nozzle rows in the middle of the print head were not fired, leaving a gap. The UV in each case is 60% of the full intensity. The fluid released in all 6 experiments was 100% distilled water. The background type in the first 3 experiments was a 4 mm mirror, and in the last 3 experiments it was 2 mm transparent glass.

As seen in Table IB, the range of TQM is from 10 μm to 22 μm (Experiments 1, 4, 5, 6); the TQMs of Experiments 2 and 3 were not obtained due to the lack of sealed mesh. For Experiment 1, although the smoothness and results were acceptable, the mesh was adhered to the mirror and the resulting TQM of 22 μm was considered too high. Experiments 4, 5 and 6 resulted in acceptable smoothness and results and a sealed mesh.

表IB. DtM測試，網目=43T，單位解析度=1440 DPI-結果。

實例系列2It seems that 2 mm transparent glass gives better results than 4 mm mirrors, and that further 2 pulses give better results than 1 pulse. It should also be noted that the frame used in experiments 2 and 3 is aluminum. Table IA. DtM test, mesh=43T, unit resolution=1440 DPI-test parameters.

Table IB. DtM test, mesh=43T, unit resolution=1440 DPI-result.

Example Series 2

In Example Series 2, 12 experiments were conducted; details are provided in Tables IIA (test parameters) and IIB (results) below. All experiments used UV Super Flex 100 ink as a sprayable emulsion. The mesh color in each case is yellow. The frame type in each case is aluminum. The unit resolution in each case is 1080 DPI. The printing speed is 375 cm/sec. The number of pulses is described in Table II. In all experiments, all 8 ink channels were fired. For all experiments, UV is 60% of full intensity, except for experiment 11, where UV is 40% of full intensity. The release fluid 122 is as described in Table IIA. The background types are described in Table IIA.

As seen in Table IIB, the range of TQM is from 7 μm to 20 μm; TQM was not obtained in Experiment 5. For experiments 1 to 4, 6, and 12, the smoothness and results are acceptable. For experiments 7 and 8, the smoothness and results are slightly acceptable. For experiments 5, 9, 10, and 11, the smoothness and results were unacceptable; as indicated in Table II, these experiments resulted in the mesh sticking to the printed surface of the platen.

The only difference between Experiments 4 and 5 is the background type 2x upper glass to polyethylene used. It seems that the former produces better results than the latter.

The only difference between Experiments 4 and 7 to 8 is the type of background used 2x top glass to 4 mm top glass. It seems that the former produces better results than the latter.

表IIB. DtM測試，網目=43T，單位解析度=1080 DPI-結果。

實例系列3Regarding experiments 9, 10 and 11, these are the only experiments using a liquid consisting of 95% distilled water and 5% ANODAL ASL (Gedacolor). Other liquids (for example, 100% distilled water, 80% distilled water + 20% dead sea salt, 80% distilled water + 20% ethanol, and 50% distilled water + 25% window cleaner + 25% isopropyl alcohol) are given acceptable or slightly acceptable Accepted smoothness and results. Table IIA. DtM test, mesh=43T, unit resolution=1080 DPI-test parameters.

Table IIB. DtM test, mesh=43T, unit resolution=1080 DPI-result.

Example Series 3

In Example Series 3, 5 experiments were conducted; details are provided in Tables IIIA (test parameters) and IIIB (results) below. All experiments used UV Super Flex 100 UV ink as a sprayable emulsion. The mesh color in each case is yellow. The frame type in each case is aluminum. The unit resolution in each case is 1080 DPI or 1440 DPI. The printing speed is 300 cm/sec or 375 cm/sec, as described in Table IIIA. The number of pulses is as described in Table IIIA. In all experiments, the two nozzle rows in the middle of the print head were not fired, leaving a gap ("11100111"). UV is 60% of full intensity. The released fluid 122 in all 6 experiments was 100% distilled water. The background type in all experiments was a 4 mm mirror.

As seen in Table IIIB, TQM ranges from 3 μm to 45 μm. For all experiments, the smoothness was acceptable, while for experiments 3, 4, and 5, the results were acceptable. For Experiments 1 and 2, due to the slight adhesion of the mesh, the results were slightly unacceptable.

表IIIB. DtM測試，網目=120T, 43T-結果。

實例系列4In Experiments 1 and 2, the number of pulses is the same for both (2), and for Experiments 3, 4, and 5, the number of pulses is different (1). It seems that this difference results in experiments 1 and 2 with slightly unacceptable results. Table IIIA. DtM test, mesh=120T, 43T-test parameters.

Table IIIB. DtM test, mesh=120T, 43T-result.

Example Series 4

In Example Series 4, 4 experiments were conducted; details are provided in the following tables IVA (test parameters) and IVB (results). In all cases, the mesh resolution is 195 (US standard). All experiments used UV Super Flex 100 UV ink as a sprayable emulsion. The mesh color in each case is gray/metal. The frame type is metal. The unit resolution in each case is 1440 DPI. The printing speed is 300 cm/sec. For all experiments, the number of pulses is one. In all experiments, the two nozzle rows in the middle of the print head were not fired, leaving a gap ("11100111"). In experiments 1 to 3, the UV was 60%, 40%, and 30% of the full intensity, while in experiment 4, the UV was 30% of the full intensity. The release fluid in experiments 1 to 3 was distilled water; in experiment 2, the release fluid was not used. The background type in the two experiments was a 3 mm mirror.

As seen in Table IVB, the TQM was 14 μm in all experiments. For experiments 1 to 3, both smoothness and results are unacceptable, while for experiment 4, smoothness and results are acceptable.

表IVB. DtM測試，網目=195 (美國標準)-結果。

In experiments 2 and 3 of Example 1 above, the frame was aluminum, and the two experiments had unacceptable smoothness and results, with 100% distilled water as the liquid. In Experiment 1 of Example 4, the frame was metal, and similar unacceptable results were obtained. On the other hand, in Experiment 2 of Example 4, although the frame was also metal, no liquid was used, and acceptable smoothness and results were observed. Obviously, the combination of liquid and frame is one of the factors to obtain acceptable smoothness and results. Under certain conditions, it has been found that no release fluid or backing paper produces better results. Based on the aforementioned tests, an emulsion can be formulated that will function without any backing surface. Table IVA. DtM test, mesh = 195 (American standard)-test parameters.

Table IVB. DtM test, mesh = 195 (American Standard)-results.

Based on the foregoing examples, it appears that the results may be influenced or impacted by: some very complex interactions of fluids (both emulsion and any release fluid); platen composition (eg, single-layer glass, double-layer glass, glass Add mirror, etc.); curing intensity (20% to 100% UV); dot density (1080, 1440); number of pulses, etc. From an analytical point of view, it seems that the combination is almost infinite. Currently, the only method for evaluating a parameter set is pragmatic; that is, each set must be tested based on the teachings in this article. However, this test is not considered excessive.

The advantages of DtM program 400 include complete elimination of template preparation and post-processing as follows:

No machines such as emulsion applicator, dryer, separate exposure unit are required.

Eliminate most chemicals (except degreasers) and more than 80% of water consumption.

All treatments can be completed without a special low UV light room. In fact, the DtM procedure can be carried out under normal factory/office lighting or daylight. During disposal, the sprayable emulsion remains in a UV-proof box or bag. The sprayable emulsion is exposed to sunlight or UV light only when it is sprayed onto the mesh 112.

Because the procedures disclosed herein can use conventional, less expensive mesh 112, stripping and re-meshing the frame 114 rather than cleaning the mesh (which requires water and chemicals and a special cleaning station) is generally more efficient and cheaper.

The original, untreated screen or mesh 112 is placed on the DtM printer 100 and a completely prepared, ready-to-use template 206 is removed from the screen. The template 206 can be placed directly on a carousel to place an image Print onto a printed surface.

A further advantage of the DtM program 400 is that each template 206 is very accurately registered on the mesh 112 so that micro-registration can be skipped when installed on the turntable. With the DtM program 400, because each template 206 is accurately positioned on the frame 106 (both absolute and relative), no or no adjustment is required. This is achieved by using the frame clamp 116. The formwork frame usually has registration holes or points fixed thereto. Different carousel manufacturers have their own registration systems. The frame clamp 116 is equipped with the same registration system (or may be an auxiliary registration system of another design). The frame clamp 116 allows precise alignment of the formwork frame 114. To achieve this, a test print is made using 4 (or 6 or more) colors, and then the turntable is fine-tuned. As long as no changes are made to the carousel (or the carousel is not misaligned) and all templates are built on the same printer, the templates will be accurately aligned.

It will be appreciated that the DtM process 400 disclosed herein has a significant reduction in either or both process time and complexity, labor and capital equipment (including dedicated lighting facilities), and a significant reduction in process chemicals and water.

The DtM program 400 can also be used for rotary screen printing. Rotary screen printing is used for marking and other slightly narrow but often repeated printing procedures (wallpaper, linear linoleum, etc.). Rotary screen printing is extremely fast for these applications, where each of the four colors (and any spot colors) is placed on a cylinder and the material passes underneath. Rotary screen printing usually uses stainless steel mesh 112 for durability and stability.

Today, many rotating templates are manufactured by large maintenance organizations (about three in Europe). The cost of each template can exceed 100 Euros and the annual cost of template replacement can be hundreds of thousands of Euros. This does not even consider the inconvenience of using a maintenance organization. Many companies will be able to recover the cost of the machine within a few quarters while reducing their dependence on expensive maintenance organizations.

It should be understood that in the foregoing description, many specific details are set forth to provide a thorough understanding of one of the examples. However, it should be understood that examples may be practiced without being limited to such specific details. In other cases, well-known methods and structures may not be described in detail to avoid unnecessarily obscuring the description of the examples. Furthermore, the examples can be used in combination with each other.

It should be noted that as used in this specification and the scope of the accompanying invention patent application, the singular forms "a", "an" and "the" include plural referents unless the context clearly stipulates otherwise. It should be understood that in the foregoing description, many specific details are set forth to provide a thorough understanding of one of the examples. However, it should be understood that examples may be practiced without being limited to such specific details. In other cases, well-known methods and structures may not be described in detail to avoid unnecessarily obscuring the description of the examples. Furthermore, the examples can be used in combination with each other. In addition, when using "about" to describe a value, this means covering small changes (up to ±10%) with the value, such as may be caused by manufacturing changes.

In addition, the order of the procedural steps in the patent application scope of the invention can be appropriately interchanged. For example, dispensing the release fluid 122 onto the platen 124 or mesh 112 may involve dispensing the release fluid onto the platen and then bringing the platen and mesh together. Alternatively, the platen and mesh can be brought together and the release fluid can be dispensed onto the mesh.

Although a limited number of examples have been disclosed, it should be understood that there are many modifications and variations thereof. For example, due to the new high/ultra high speed print head technology that allows jetting onto a vertical surface, the "orientation" of the printing machine/table can be changed from horizontal to vertical.

100: Direct Screen Screen (DtM) printing machine 110: Mesh support system 112: pre-stretched mesh 112a: bundle 112b: beam 114: Frame 116: Fixture 120: Pressure plate support system 122: release fluid 124: pressure plate 124a: top surface/smooth surface 126: Fluid dispenser/sprinkler 128: layer/background type 130: Inkjet printer 132: Print head 134: Printing press carriage 202: arrow 204: Arrow 206: Screen template/template 208: Ultraviolet (UV) curing source/UV source 210: arrow 300: combination 302: Dispersible emulsion 302': sprayable lotion 302'a: flat bottom surface/underside 302'b: top surface 350: combination 400: DtM program 405: Step 410: Step 415: Step 420: Step 425: Step

The features of the examples of the present invention will become apparent with reference to the detailed description and drawings below, in which similar element symbols correspond to similar but possibly different components. For the sake of brevity, element symbols or features with a previously described function may or may not be described in conjunction with other drawings in which they appear.

FIG. 1 shows a direct screen printing machine according to an example of the present invention.

FIGS. 2A to 2E depict in cross-sectional view elements of a screen printing process using a direct screen printing machine according to an example of the present invention.

3A to 3B schematically illustrate an emulsion on a mesh according to an example of the present invention, thereby providing a comparison between the current technology (FIG. 3A) and the teachings herein (FIG. 3B).

4 is a flowchart showing a screen printing method according to an example of the present invention.

100: Direct Screen Screen (DtM) printing machine

110: Mesh support system

112: pre-stretched mesh

114: Frame

116: Fixture

120: Pressure plate support system

122: release fluid

124: pressure plate

126: Fluid dispenser/sprinkler

130: Inkjet printer

132: Print head

134: Printing press carriage

Claims (15)

A direct screen printing machine for establishing a screen template, which includes: A frame for holding a pre-stretched mesh in place during the application of a sprayable emulsion; A fixture for holding the frame; A pressure plate for holding a release fluid against one side of the pre-stretched mesh; A fluid dispenser for dispensing the release fluid onto the platen or mesh; and A printing press carriage that supports a printing head to print the sprayable emulsion on the side of the pre-stretched mesh opposite the platen. The direct screen printing machine of claim 1, wherein the jig is configured to hold the frame and the pre-stretched mesh firmly and firmly in place during the application of the sprayable emulsion. The direct screen printing machine of claim 1, wherein the platen is configured to firmly hold the release fluid against the bottom of one of the pre-stretched screens. The direct screen printing machine of claim 3, wherein the platen is smooth, hard, and does not penetrate the release fluid and resists dents and cracks. The direct screen printing machine as claimed in claim 1, wherein the release fluid is applied to the platen with a very fine and uniform coating or directly applied to the mesh when the release fluid is placed on the platen to prevent Adhere to the platen during the application of the sprayable emulsion. The direct screen printing machine of claim 1, wherein the release fluid is configured to inhibit dot expansion while providing a smooth, non-reactive surface for the sprayable emulsion after curing. The direct screen printing machine of claim 1, wherein the release fluid includes water and at least one sufficient emulsifier to prevent evaporation of the release fluid. The direct screen printing machine of claim 1, wherein the sprayable emulsion has a low viscosity of about 4 cP to about 15 cP and is both durable and flexible/elastic. The direct screen printing machine as claimed in claim 8, wherein the sprayable emulsion is a UV activated acrylate monomer having one of elastomer quality after curing. The direct screen printing machine of claim 1 further includes a UV source for curing the sprayable emulsion and forming a template for screen printing. A program that contains: A direct screen printing machine is provided, which includes: a jig for holding a frame configured to hold a pre-stretched mesh in place during the application of a sprayable emulsion; a platen, which Used to hold a release fluid against one side of the pre-stretched mesh; and a printer carriage that supports a printing head to print the jettable emulsion on the side of the pre-stretched mesh opposite the platen ; Place the frame in the fixture; Dispense the release fluid onto the platen or mesh; Bring the pressure plate and the mesh together in a tensioned configuration; Print the sprayable emulsion on the mesh; and The sprayable emulsion is cured using UV radiation. The procedure of claim 11, wherein the sprayable emulsion after curing forms a screen template, wherein the opening in the screen template is to be used to form an image on a surface. The procedure of claim 11, wherein the release fluid is configured to inhibit spot expansion while not sticking to the sprayable emulsion after it solidifies. The process of claim 11, wherein the release fluid includes water and at least one sufficient amount of emulsifier to prevent evaporation of the release fluid. The procedure of claim 11, wherein the sprayable emulsion is one of UV-activated acrylate monomers having an elastomeric quality after curing.

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