A high-precision flexographic printing device

Abstract

The present invention provides a high-precision flexographic printing device, comprising an ink cartridge, an ink transfer roller, a platen roller, a printed material conveying platform, and a heating device I for heating the printed material. The platen roller is an electrostatic roller, and the platen roller is disposed above the printed material conveying platform. An ink transfer roller is disposed above the ink cartridge, and the ink transfer roller and the platen roller are disposed adjacent to each other. A heating device I is disposed behind the platen roller and above or below the printed material conveying platform. Ink is adsorbed on the platen roller. When the potential on the platen roller changes, the ink is separated from the platen roller by repulsive force. When the platen roller transfers the ink to the printed material, the ink transfer does not require the application of a bearing force. Therefore, the flexographic printing plate does not suffer from dot gain or deformation of the image due to compression, thereby ensuring high precision and accuracy of the printed pattern.

Description

Technical Field

[0001] The present invention relates to the field of flexographic printing production, in particular to a high-precision flexographic printing device. Background Art

[0002] Flexographic printing is currently the fastest and most efficient printing method, and it's also the fastest-growing. Both its press manufacturing technology and flexographic application technology represent the highest level of flexographic printing. The majority of commercial packaging currently available is flexographically printed. However, due to the use of a grid roller for ink transfer and the stress-bearing requirements of the impression cylinder, the high-precision screen patterns produced cannot match those of offset and inkjet printing. Therefore, we have developed a transfer method that uses piezoelectric adsorption to deliver a high-precision ink pattern to the impression cylinder in flexographic printing, resolving the issues of insufficient printing precision due to screen printing and distortion of the printed pattern caused by cylinder deformation.

[0003] Existing technical defects:

[0004] 1. The printing accuracy of flexographic printing is not enough, and the pattern is easily deformed due to the bearing capacity of the impression cylinder;

[0005] 2. The printing speed, water-ink balance and ink emulsification of offset printing will lead to lower printing speed and lower printing yield;

[0006] Inkjet printing has higher printing speed and printing cost. Summary of the Invention

[0007] To solve the above problems, the present invention provides a high-precision flexographic printing device. When the potential on the embossing roller changes, the ink is separated from the embossing roller by repulsive force. When the embossing roller transfers the ink to the printed matter, there is no need to apply a bearing force to transfer the ink. The flexible plate will not suffer from dot enlargement and extrusion deformation of the image, ensuring high precision and accuracy of the printed pattern.

[0008] The technical solution of the present invention is: a high-precision flexographic printing device, including an ink cartridge, an ink transfer roller, an impression roller, a printed material conveying platform, and a heating device I for heating the printed material, the impression roller being an electrostatic roller, a impression roller being provided above the printed material conveying platform, an ink transfer roller being provided above the ink cartridge, and the ink transfer roller and the impression roller being arranged adjacent to each other; a heating device I is provided behind the impression roller and above or below the printed material conveying platform.

[0009] The size of the ink layer in the ink cartridge that soaks the ink transfer roller is between 0.05mm and 10cm.

[0010] The embossing roller includes a conductive layer. An insulating layer with a thickness of 5 μm-1 mm is formed outside the graphite layer of the embossing roller. The insulating layer includes a hollow area, and the conductive layer is directly exposed in the hollow area.

[0011] The conductive layer of the embossing roller is divided into blocks, and each block is separated by an insulating dividing layer I. Two conductors or electrodes are provided on the side of the rotating end of the embossing roller, and the two conductors are separated by an insulating dividing layer II or the two electrodes are separated by an insulating dividing layer II; one end of the two conductors is respectively connected to the positive and negative poles of the power supply, and the other end of one of the conductors slides in contact with the conductive layer at the lower part of the rotating end of the embossing roller, and the area corresponding to the conductive layer at the lower part of the rotating end of the embossing roller corresponds to the printing area of ​​the embossing roller, and the other end of the other conductor slides in contact with other conductive layers at the rotating end of the embossing roller.

[0012] A conductive layer is provided on the ink transfer roller, and the conductive layer of the ink transfer roller is divided into blocks, and each block is separated by an insulating partition layer. Two conductors or electrodes are provided on the side of the rotating end of the ink transfer roller, and the two conductors are separated by an insulating partition layer or the two electrodes are separated by an insulating partition layer; one end of the two conductors is connected to the positive and negative poles of the power supply respectively, and the other end of one conductor slides in contact with the conductive layer of the rotating end of the ink transfer roller corresponding to the transfer area where the embossing roller performs transfer, and the other end of the other conductor is connected to the conductive layer of other parts of the rotating end of the ink transfer roller that slides in contact with the embossing roller; the conductor of the conductive layer of the rotating end of the ink transfer roller corresponding to the transfer area where the embossing roller performs transfer has the same polarity as the power supply connected to the conductor of the conductive layer at the lower part of the rotating end of the embossing roller that slides in contact with the embossing roller.

[0013] The hardness of the surface of the ink transfer roller and the embossing roller is ≥2H, and the glossiness is between 20-80°.

[0014] A device for applying static electricity to the printed material, such as an electrostatic generator, is provided in front of the embossing roller. The polarity of the charge applied to the printed material is opposite to the charge carried by the conductive layer at the bottom of the embossing roller. A device for eliminating static electricity on the printed material is provided behind the embossing roller.

[0015] A stirring device is provided in the ink cartridge.

[0016] A varnish printing roller or varnish nozzle is provided behind the heating device I and above the printed material conveying platform, and a heating device II for heating the printed material is provided behind the varnish printing roller or varnish nozzle and above or below the printed material conveying platform.

[0017] In the printing area corresponding to the embossing roller or in front of the printing area and located on the side of the printed material conveying platform, an infrared sensor or photoelectric sensor is provided to detect whether there is printed material passing by. The infrared sensor or photoelectric sensor drives the motor to rotate the embossing roller and the ink transfer roller through signals or electrical connections.

[0018] The beneficial effects of the present invention are as follows: the high-precision flexographic printing device provided in the present application changes the original ink transfer method through the grid roller into the method of electrostatic adsorption and mutual repulsion or positive and negative charge adsorption and like charge repulsion through electrostatic adsorption of ink, thereby ensuring the high precision of the pattern. Moreover, because the ink is adsorbed on the embossing roller by electrostatic adsorption, when the potential on the embossing roller changes, the ink is separated from the embossing roller by the repulsive force. When the embossing roller transfers the ink to the printed matter, there is no need to transfer the ink by applying a bearing force. The flexible plate does not have the phenomenon of dot enlargement and extrusion deformation of the image and text, thereby ensuring the high precision and high accuracy of the printed pattern.

[0019] Through electrostatic printing, the ink is sputtered onto the surface of the printed object at a certain speed through the repulsive force of the electric charge. The adhesion between the ink and the printed object is improved, the surface requirements of the printed object are lower, and it has a wider adaptability. Printing can be completed on the surface tension of the printed object within 5-400 dynes / meter.

[0020] The ink pattern is formed through the insulating layer of the embossing roller. The insulation precision can be achieved below 5μm, so the printing accuracy is greatly improved. There is no grid pattern of traditional flexographic printing, and the embossing roller has no direct contact with the printed object. The pattern will not be deformed and the printed object will not change shape or other physical characteristics due to squeezing.

[0021] The entire printing process is carried out through charge transfer. The printing speed is faster than traditional flexographic printing and can reach ≥5m / s.

[0022] Because the viscosity requirement for the ink is lower, patterns with a wider color gamut can be printed, the patterns are more realistic and vivid, and patterns with an NTSC color gamut ≥180% can be printed.

[0023] Because the printing precision is high enough, this method can be used to directly print more complex patterns such as anti-counterfeiting patterns or anti-counterfeiting logos, and the minimum size of the pattern can be printed to ≤50μm.

[0024] Because piezoelectric printing is used, the position of the printed object can be detected by infrared or other detectors to interrupt or start printing. Therefore, the printed object does not need to be a continuous object like traditional flexible printing, and some intermittent or individual objects can be directly printed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention.

[0026] Figure 2 It is a schematic diagram of the structure of the conductive layer of the embossing roller connected to the power supply. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings and specific embodiments to clearly and completely describe the technical solutions of the present invention. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments based on the content of the present invention described below. In the present invention, unless otherwise clearly specified and limited, the technical terms used in this application should have the common meanings understood by those skilled in the art of the present invention.

[0028] like Figure 1 and Figure 2 As shown, a high-precision flexographic printing device includes an ink cartridge 1, an ink transfer roller 2, an impression roller 3, a printed material conveying platform 4, and a heating device I5 for heating the printed material. The impression roller 3 is located above the printed material conveying platform 4, and the ink transfer roller 2 is located above the ink cartridge 1, adjacent to the impression roller 3. A heating device I5 is located behind the impression roller 3 and above or below the printed material conveying platform 4. The heating device I5 heats the printed material to facilitate the curing of the ink on the printed material. For example, in the case of solvent-based ink, the solvent in the ink is evaporated, curing the ink onto the desired printed material surface.

[0029] The size of the ink layer 10 in the ink cartridge that wets the ink transfer roller 2 is between 0.05 mm and 10 cm.

[0030] The embossing roller 3 is an electrostatic roller. The printing device of this application is for printing ink containing solvent. When the ink on the ink transfer roller 2 contacts the embossing roller 3, the embossing roller adsorbs the ink on the surface in a fixed pattern through electrostatic adsorption or positive and negative charge adsorption.

[0031] The embossing roller 3 includes a conductive layer 33, such as a graphite layer. In order to ensure the authenticity of the pattern on the embossing roller, we form a 5μm-1mm thick insulating layer 34 on the outside of the graphite layer of the embossing roller by etching, inkjet, laser, coating or other methods for the positions where ink does not need to be printed (absorbed). That is, the positions where ink needs to be printed (absorbed) are hollowed out to form hollow areas, directly exposing the conductive layer 33. The other positions are all insulating layers 34, which cannot absorb ink. That is, the pattern area to be printed is hollowed out, and the area where the pattern does not need to be printed is coated with an insulating layer.

[0032] The pattern formation of the ink is achieved through the insulating layer 34. The precision size of the insulation can be achieved below 5μm, so the printing accuracy is greatly improved. There is no grid pattern of traditional flexographic printing, and the embossing roller has no direct contact with the printed object. The pattern will not be deformed and the printed object will not change its shape or other physical characteristics due to squeezing.

[0033] The conductive layer of the embossing roller 3 is divided into blocks, and each block is separated by an insulating dividing layer I 30. Two conductors 31 or electrodes are provided on the side of the rotating end of the embossing roller, and the two conductors 31 are separated by an insulating dividing layer II 32 or the two electrodes are separated by an insulating dividing layer II 32.

[0034] One end of a conductor 31 is connected to the positive pole of the power supply 6, and the other end slides in contact with the upper conductive layer of the rotating end of the embossing roller 3. One end of another conductor 31 is connected to the negative pole of the power supply, and the other end slides in contact with the lower conductive layer 33 of the rotating end of the embossing roller. The area corresponding to the lower conductive layer of the rotating end of the embossing roller corresponds to the printing area 35 of the embossing roller, that is, the area of ​​the lower end of the embossing roller closest to the printed material conveying platform 4.

[0035] Therefore, when the embossing roller is located in the printing area 35, the charge on the surface of the embossing roller is opposite to that at other locations.

[0036] The ink may be an ink containing magnetic material or an ink having an electric charge opposite to that of the upper end of the embossing roller.

[0037] The embossing roller absorbs the ink on the embossing roller by electrostatic adsorption. When the ink is printed on the printed matter, the potential changes, causing the embossing roller to form a repulsive force on the ink, and the ink will spontaneously detach from the embossing roller. Therefore, when the embossing roller transfers the ink to the printed matter, there is no need to apply a bearing force to transfer the ink.

[0038] A conductive layer 20, such as a graphite layer, is provided on the ink transfer roller 2. The ink transfer roller 2 can have the same structure as the embossing roller. The conductive layer of the ink transfer roller 2 is divided into blocks, and each block is separated by an insulating partition layer. Two conductors or electrodes are provided on the side of the rotating end of the ink transfer roller, and the two conductors are separated by an insulating partition layer or the two electrodes are separated by an insulating partition layer.

[0039] One end of one piece is connected to the negative pole of the power supply, and the other end slides to contact the conductive layer of the rotating end of the ink transfer roller corresponding to the transfer area 21 where the embossing roller performs transfer. One end of the other piece is connected to the positive pole of the power supply, and the other end slides to contact the conductive layer of other parts of the rotating end of the ink transfer roller.

[0040] In order to further confirm whether it is time to start printing, an infrared sensor or photoelectric sensor 7 is provided in the printing area corresponding to the embossing roller or in front of the printing area and on the side of the printed material conveying platform to detect whether there is printed material passing by. The infrared sensor or photoelectric sensor 7 drives the motor that rotates the embossing roller and the ink transfer roller through a signal or an electrical connection. The infrared sensor or photoelectric sensor 7 senses that there is printed material passing by and transmits a signal to the motor that drives the embossing roller and the ink transfer roller to rotate, thereby interrupting or starting printing. Therefore, the printed object does not need to be a continuous object like traditional flexible printing, and some intermittent or separate objects can also be directly printed.

[0041] The hardness of the surface of the ink transfer roller and the embossing roller is ≥2H, and the glossiness is between 20-80°.

[0042] A device for applying static electricity to the printed matter, such as an electrostatic generator 8, is provided in front of the impression roller, and the polarity of the charge applied to the printed matter is the same as the charge on the upper end of the impression roller, so that ink can be transferred from the impression roller to the printed matter more easily.

[0043] A device 9 for eliminating static electricity on printed materials, such as an ion blower or other existing devices, is provided behind the embossing roller.

[0044] The ink cartridge is provided with a stirring device 11 to prevent the ink in the ink cartridge from being left for too long and having poor fluidity. The stirring device 11 is driven by a stirring motor.

[0045] Furthermore, a varnish printing roller or varnish nozzle 51 is located behind heating device I5 and above the printed material conveying platform. A heating device II 52 for heating the printed material is located behind the varnish printing roller or varnish nozzle and above or below the printed material conveying platform. A layer of varnish is printed on the ink surface by coating or spraying, and then cured by the heating device. This not only improves the ink's weather resistance and scratch resistance, but also further enhances the surface hardness and surface activity of the printed object.

[0046] The entire printing process is carried out through charge transfer. The printing speed is faster than traditional flexographic printing and can reach ≥5m / s.

[0047] Because the viscosity requirement for the ink is lower, patterns with a wider color gamut can be printed, the patterns are more realistic and vivid, and patterns with an NTSC color gamut ≥180% can be printed.

[0048] Because the printing precision is high enough, this method can be used to directly print more complex patterns such as anti-counterfeiting patterns or anti-counterfeiting logos, and the minimum size of the pattern can be printed to ≤50μm.

[0049] The ink is transferred statically throughout the system, so it can adapt to inks of different viscosities and states. Ink viscosities ranging from 10,000 to 500,000 centipoise can be used normally. When there are special requirements for printed patterns or dyes, powdered pigments can also be used for printing.

[0050] The inks that can be used for printing are as follows:

[0051] An electrostatic adsorption ink comprises 1-5 parts of a high molecular polymer, 3-8 parts of titanium dioxide, 1-2 parts of an auxiliary agent, 1-2 parts of a binder, 1-8 parts of a filler, 5-20 parts of a solvent and 1-5 parts of a magnetic high molecular material.

[0052] The high molecular polymer includes one or more of polyvinyl butyral, polymethyl methacrylate, polyethylene oxide, ethyl acetate, n-propyl acetate, n-butyl acetate and the like.

[0053] The additives include: B0K-L-301, B0K-L-302, B0K-L-303, B0K-L-305, B0K-L-307, B0K-L-308, B0K-L-309, B0K-L-310, BYK163, BYK333, BYK310, BYK306, B0K-F-501, B0K-F-502, B0K-F-505, B0K-F-508, B0K-F-512, which are one or more of dodecyl alcohol ester, benzyl alcohol, ethylene glycol butyl ether, propylene glycol phenyl ether, and ethylene glycol butyl ether acetate.

[0054] The binder comprises one or more of guanidine chloride acetate, hydroxypropyl methylcellulose, toluene diisocyanate, vinylguanamine, and ethylene glycol butyl ether acetate.

[0055] The filler includes one or more of copper sulfate, calcium sulfate, calcium carbonate, and water-soluble silicon dioxide.

[0056] The solvent includes one or more of distilled water, ethanol, ethylene glycol, ethyl acetate, toluene, xylene, chloroform, dichloromethane, and n-hexane.

[0057] The magnetic polymer materials include: poly 1,4-bis(2,2,6,6-tetramethyl-4-hydroxy-1-oxyl free radical piperidine) diacetylene, pyrolyzed polyacrylonitrile, and PPH-FeSO4 magnetic polymer.

[0058] The particle size of the magnetic polymer material is 200-500nm.

[0059] Poly (1,4-bis(2,2,6,6-tetramethyl-4-hydroxy-1-oxypiperidinyl)butadiyne, or BIPO, can be polymerized into single or polycrystalline polymers under UV illumination or at temperatures around 100°C. Modifying the polymerization conditions can alter the magnetic properties over a wide range, from superparamagnetism to ferromagnetism.

[0060] Pyrolysis of polyacrylonitrile: Pyrolysis of polyacrylonitrile at 900-1100°C produces a black powder containing a crystalline phase and an amorphous phase with a medium saturation magnetization, in which the crystalline phase plays a magnetic role.

[0061] PPH-FeSO4 is polybis(2,6-pyridyloctanedinitrile)-ferrous sulfate. FeSO2 is a black solid magnetic polymer with light weight and good heat resistance. It will not decompose at 300°C in air and is not easily soluble in organic solvents. It is a very good magnetic material.

[0062] The method for preparing the piezoelectric electrostatic adsorption ink comprises the following steps:

[0063] (1) Adding a polymer to a solvent and dissolving the polymer in the solvent;

[0064] (2) Continue adding additives to the solvent to dissolve;

[0065] (3) Add the connecting material, titanium dioxide, filler and magnetic polymer material and disperse them evenly;

[0066] (4) Evaporation and concentration to a viscosity of 5 to 280 Pa·s;

[0067] (5) Cool to room temperature, which is 15-35°C.

[0068] After concentration, the ink material will be in a semi-fluid state. Direct mixing will result in uneven mixing, so a solvent is needed to reduce its viscosity to ensure better dispersion of the magnetic polymer material. After mixing, the solvent needs to be evaporated to adjust the final viscosity of the ink.

[0069] The ink provided in this application contains a magnetic polymer material and is in a semi-fluid state. It can be electrostatically adsorbed and transferred by using piezoelectric printing or electrostatically assisted printing systems, achieving a more efficient ink patterning effect. The impression roller adsorbs the ink onto the impression roller through electrostatic adsorption. When the ink is printed on the printed material, the potential changes, causing the impression roller to exert a repulsive force on the ink, causing the ink to spontaneously detach from the impression roller. This eliminates the need for the impression roller to transfer the ink to the printed material by applying a bearing force.

[0070] The raw material titanium dioxide and high molecular polymer in this application undergo redox reactions under voltage drive to change the material characteristics. The changed material characteristics are characterized by different colors due to different absorption degrees of different spectra.

[0071] The ink pattern is formed by using piezoelectric printing or electrostatic assisted printing system printing, which is more efficient and has a higher degree of refinement of the pattern, and can achieve printing precision control of ≤2μm. The electrostatic adsorption ink provided by the present invention is an electrochromic ink, which can be formed into a film by various methods such as coating, spraying, transfer, and silk screen printing. The ink of the present application can change its structural morphology under the influence of a specific electric field or static electricity, forming a micron-level strip grating on the anti-counterfeiting label, and forming different halos by diffuse reflection of the micron-level strip grating. The color of the halo will show different colors depending on the size of the grating. Therefore, when a specific grating is combined, the halo displayed is also specific. This part of the application can be used in anti-counterfeiting labels.

[0072] The current ink printing method cannot achieve μm-level pattern control due to the ink's astigmatism. If the ink printing size is around 5μm, a grating structure will be formed. Gratings of different widths will form a colorful astigmatism effect during the light reflection process. The printing of anti-counterfeiting labels uses the grating astigmatism effect, but anti-counterfeiting labels can only be achieved through multi-layer spraying or vapor deposition, which is not only costly but also unable to produce large-size patterns.

[0073] Example 1:

[0074] A method for preparing piezoelectric electrostatic adsorption ink comprises the following steps:

[0075] 1. Heat 10 kg of ethylene glycol (solvent) to 60°C, add 4 kg of ethyl acetate (polymer), stir thoroughly to dissolve, cool to 25°C, and continue stirring for 20 minutes;

[0076] 2. Add 2 kg of B0K-L-303 additive and continue stirring for 5 minutes, then heat the solution to 50°C and continue stirring for 10 minutes;

[0077] 3. Transfer the resulting solution into a reactor and add 2kg of guanidine chloride (binder), 2kg of titanium dioxide, 3kg of calcium carbonate and 2kg of magnetic polymer material. Heat the reactor to 120°C and stir at high speed (the stirring liquid flow rate is higher than 10m / s).

[0078] 4. Transfer the obtained liquid into an evaporating dish and heat it to control the temperature of the liquid between 60-80°C. Evaporate and concentrate the liquid to a total weight of 16 kg.

[0079] 5. Cool the liquid to room temperature 25℃ and it is done.

[0080] Example 1:

[0081] A method for preparing an electrostatic adsorption ink comprises the following steps:

[0082] 1. Heat 10 kg of ethylene glycol (solvent) to 60°C, add 4 kg of ethyl acetate (polymer), stir thoroughly to dissolve, cool to 25°C, and continue stirring for 20 minutes;

[0083] 2. Add 2 kg of B0K-L-303 additive and continue stirring for 5 minutes, then heat the solution to 50°C and continue stirring for 10 minutes;

[0084] 3. Transfer the resulting solution into a reactor, add 2 kg of guanidine chloride (binder), 2 kg of titanium dioxide, 3 kg of calcium carbonate, and 2 kg of poly (1,4-bis (2,2,6,6-tetramethyl-4-hydroxy-1-oxyl piperidine) butadiene), heat the reactor to 120°C, and stir at high speed (the stirring liquid flow rate is higher than 10 m / s);

[0085] 4. Transfer the obtained liquid into an evaporating dish and heat it to control the temperature of the liquid between 60-80°C. Evaporate and concentrate the liquid until the total weight of the liquid is concentrated to a viscosity of 158 Pa·s.

[0086] 5. Cool the liquid to room temperature 25℃ and it is done.

[0087] Example 2:

[0088] A method for preparing an electrostatic adsorption ink comprises the following steps:

[0089] 1. Heat 20 kg of ethylene glycol (solvent) to 60°C, add 5 kg of ethyl acetate (polymer), stir thoroughly to dissolve, cool to 22°C, and continue stirring for 30 minutes;

[0090] 2. Add 2 kg of B0K-L-310 additive and continue stirring for 5 minutes, then heat the solution to 50°C and continue stirring for 12 minutes;

[0091] 3. Transfer the obtained solution into a reactor and add 2kg hydroxypropyl methylcellulose (binder), 8kg titanium dioxide, 8kg calcium carbonate and 5kg PPH-FeSO4 magnetic polymer. Heat the reactor to 120°C and stir at high speed (the stirring liquid flow rate is higher than 10m / s).

[0092] 4. Transfer the resulting liquid into an evaporating dish and heat it to a temperature between 60-80°C. Evaporate and concentrate the liquid to a viscosity of 280 Pa·s.

[0093] 5. Cool the liquid to room temperature (22°C) and the process is complete.

[0094] Example 3:

[0095] A method for preparing an electrostatic adsorption ink comprises the following steps:

[0096] 1. Heat 15 kg of ethylene glycol (solvent) to 60°C, add 1 kg of ethyl acetate (polymer), stir thoroughly to dissolve, cool to 20°C, and continue stirring for 20 minutes;

[0097] 2. Add 1 kg of B0K-L-310 additive and continue stirring for 5 minutes, then heat the solution to 50°C and continue stirring for 8 minutes;

[0098] 3. Transfer the resulting solution into a reactor and add 1 kg vinylguanamine (binder), 3 kg titanium dioxide, 1 kg copper sulfate and 5 kg pyrolyzed polyacrylonitrile. Heat the reactor to 120°C and stir at high speed (the stirring liquid flow rate is higher than 10 m / s).

[0099] 4. Transfer the resulting liquid into an evaporating dish and heat it to a temperature between 60-80°C. Evaporate and concentrate the liquid to a viscosity of 76 Pa·s.

[0100] 5. Cool the liquid to room temperature (20°C).

[0101] Example 4:

[0102] A method for preparing an electrostatic adsorption ink comprises the following steps:

[0103] 1. Heat 15 kg of ethylene glycol (solvent) to 60°C, add 3 kg of ethyl acetate (polymer), stir thoroughly to dissolve, cool to 21°C, and continue stirring for 25 minutes;

[0104] 2. Add 1.5 kg of B0K-L-310 additive and continue stirring for 5 minutes, then heat the solution to 50°C and continue stirring for 10 minutes;

[0105] 3. Transfer the resulting solution into a reactor, add 1.2 kg of guanidine chloride (binder), 5 kg of titanium dioxide, 4 kg of calcium sulfate, and 3 kg of pyrolyzed polyacrylonitrile, heat the reactor to 120°C, and stir at high speed (the stirring liquid flow rate is higher than 10 m / s);

[0106] 4. Transfer the resulting liquid into an evaporating dish and heat it to a temperature between 60-80°C. Evaporate and concentrate the liquid to a viscosity of 118 Pa·s.

[0107] 5. Cool the liquid to room temperature 22℃ and it is done.

[0108] The magnetic polymer materials in the aforementioned embodiments of this application have a particle size of 200-500 nm. The inks prepared in Examples 1-4 remain in a semi-fluid state throughout the printing process, eliminating the issues of water-ink balance and ink emulsification encountered during offset printing. Using piezoelectric electrostatic printing to print ink patterns, a printing precision of ≤2 μm can be achieved.

[0109] The above is only the preferred embodiment of the present invention, not all the embodiments, and the protection scope of the present invention is not limited thereto. The various technical features of the above-mentioned embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the various technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention. It should be pointed out that for those skilled in the art and any technician familiar with this technical field, without departing from the spirit of the overall concept of the present invention and the principles of the present invention, the technical solution and its inventive concept of the present invention are equivalently replaced or changed, and a number of changes and improvements are made, which should also be regarded as the protection scope of the present invention.

Claims

1. A high-precision flexographic printing device, characterized in that: The invention comprises an ink cartridge (1), an ink transfer roller (2), a embossing roller (3), a printed matter conveying platform (4), and a heating device I (5) for heating printed matter. The embossing roller (3) is an electrostatic roller. The embossing roller (3) is arranged above the printed matter conveying platform (4). An ink transfer roller (2) is arranged above the ink cartridge (1). The ink transfer roller (2) and the embossing roller (3) are arranged adjacent to each other. A heating device I (5) is arranged behind the embossing roller (3) and above or below the printed matter conveying platform (4). The embossing roller (3) includes a conductive layer (33), an insulating layer (34) with a thickness of 5 μm-1 mm is formed outside the conductive layer of the embossing roller, and the insulating layer (34) includes a hollow area, and the conductive layer (33) is directly exposed in the hollow area; The conductive layer of the embossing roller (3) is divided into blocks, each block is separated by an insulating partition layer I (30), two conductors (31) are provided on the side of the rotating end of the embossing roller, and the two conductors (31) are separated by an insulating partition layer II (32); one end of the two conductors is respectively connected to the positive electrode and the negative electrode of the power supply (6), the other end of one of the conductors slides in contact with the conductive layer (33) below the rotating end of the embossing roller, and the area corresponding to the conductive layer below the rotating end of the embossing roller corresponds to the printing area (35) of the embossing roller, and the other end of the other conductor slides in contact with other conductive layers of the rotating end of the embossing roller; The ink transfer roller (2) is provided with a conductive layer (20), and the conductive layer of the ink transfer roller (2) is divided into blocks, each block is separated by an insulating partition layer, and two conductors are provided on the side of the rotating end of the ink transfer roller, and the two conductors are separated by an insulating partition layer; one end of the two conductors is respectively connected to the positive electrode and the negative electrode of the power supply (6), the other end of one conductor slides in contact with the conductive layer of the rotating end of the ink transfer roller corresponding to the transfer area (21) where the embossing roller performs transfer, and the other end of the other conductor is connected to the conductive layer of other parts of the rotating end of the ink transfer roller; the conductor of the conductive layer of the rotating end of the ink transfer roller corresponding to the transfer area (21) where the embossing roller performs transfer and the conductor of the conductive layer (33) at the lower part of the rotating end of the embossing roller that slides in contact have the same polarity as the power supply connected thereto.

2. The high-precision flexographic printing device according to claim 1, characterized in that: The size of the ink layer (10) in the ink box that soaks the ink transfer roller (2) is between 0.05mm and 10cm.

3. The high-precision flexographic printing device according to claim 1, characterized in that: The hardness of the surface of the ink transfer roller and the embossing roller is ≥2H, and the glossiness is between 20-80°.

4. The high-precision flexographic printing device according to claim 1, characterized in that: A device for applying static electricity to the printed matter is provided in front of the embossing roller, and the polarity of the charge applied to the printed matter is opposite to the charge carried by the conductive layer (33) at the bottom of the embossing roller; a device (9) for eliminating static electricity from the printed matter is provided behind the embossing roller.

5. The high-precision flexographic printing device according to claim 1, characterized in that: A stirring device (11) is provided in the ink box.

6. The high-precision flexographic printing device according to claim 1, characterized in that: A varnish printing roller or varnish nozzle (51) is provided behind the heating device I (5) and above the printed matter conveying platform, and a heating device II (52) for heating the printed matter is provided behind the varnish printing roller or varnish nozzle and above or below the printed matter conveying platform.

7. The high-precision flexographic printing device according to claim 1, characterized in that: An infrared sensor or a photoelectric sensor (7) is provided in the printing area corresponding to the embossing roller or in front of the printing area and on the side of the printed material conveying platform to detect whether printed materials are passing by. The infrared sensor or the photoelectric sensor (7) drives the motor for rotating the embossing roller and the ink transfer roller through a signal or an electrical connection.

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