Doctor blade and flexographic printing system having the same

Abstract

This utility model discloses a doctor blade and a flexographic printing system incorporating the doctor blade. When the doctor blade of this utility model scrapes ink from the outer wall of the anilox roller, the cells are filled with ink, and ink lines are left on the surface of the anilox roller. It is easy to understand that compared with the effect of traditional doctor blades scraping ink on the anilox roller, the doctor blade of this utility model produces many ink lines on the entire surface of the anilox roller after scraping ink. These ink lines protrude from the roller surface of the anilox roller, allowing the ink in the cells to communicate with each other and increasing the amount of ink transferred. Therefore, when the ink is transferred to the solid area of ​​the flexographic printing plate, it is easier to level than the traditional ink application method. Due to the increased amount of ink, the smoothness and saturation of the ink are higher, so the final visual effect gives a strong sense of thickness, greatly improving the expressiveness of solid colors in flexographic printing.

Description

Technical Field

[0001] This utility model relates to the field of flexographic printing technology, and in particular to a doctor blade and a flexographic printing system having the doctor blade. Background Technology

[0002] Currently, the mainstream printing methods include offset printing, gravure printing, screen printing, flexographic printing, and digital printing. For packaging products, offset and gravure printing are the main methods, while flexographic printing is mainly used in the labeling field. In recent years, flexographic printing has also been expanding into the packaging field. The core advantages of flexographic printing lie in its environmental friendliness, production efficiency, and cost control. It is suitable for products with high environmental requirements, such as food, pharmaceuticals, and cigarettes. Its characteristics include thick and vibrant colors, and it can use water-based and UV inks.

[0003] Flexographic printing requires an anilox roller to transfer ink onto the flexographic printing plate. Its ink application is slightly less than that of gravure printing. Most flexographic inks are water-based or UV inks, and their fluidity is also worse than that of solvent inks, which results in a lower leveling speed of the ink on the anilox roller. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a doctor blade that helps to improve the ink application volume and leveling speed in flexographic printing.

[0005] This utility model also proposes a flexographic printing system with the above-mentioned doctor blade.

[0006] According to a first aspect of the present invention, a doctor blade is applied in a flexographic printing system, comprising: a blade body; a doctor blade connected to the blade body, wherein the doctor blade has a plurality of notches spaced apart along the length direction of the doctor blade, the width of the notches being W, satisfying: 10µm≤W≤30µm; wherein the width direction of the notches is the same as the length direction of the doctor blade.

[0007] The doctor blade according to the embodiments of this utility model has at least the following beneficial effects:

[0008] When the doctor blade of this invention scrapes ink onto the outer wall of the anilox roller, the cells are filled with ink, and ink lines are left on the surface of the cell wall. It is easy to understand that compared with the effect of traditional doctor blades scraping ink on the anilox roller, the doctor blade of this invention produces many ink lines on the entire surface of the anilox roller. These ink lines protrude from the roller surface of the anilox roller, connect the ink in the cells, and increase the amount of ink transferred. Therefore, when the ink is transferred to the solid area of ​​the flexographic printing plate, it is easier to level than the traditional ink application method. Due to the increased amount of ink, the smoothness and saturation of the ink are higher, so the final visual effect gives people a strong sense of thickness, which greatly improves the expressiveness of solid colors in flexographic printing.

[0009] According to some embodiments of the present invention, the depth of the notch is D, which satisfies: 5µm≤D≤15µm; wherein, the depth direction of the notch is perpendicular to the length direction of the squeegee blade and the thickness direction of the squeegee blade.

[0010] According to some embodiments of the present invention, the interval between two adjacent notches arranged along the length direction of the scraping blade is H, which satisfies: 10µm≤H≤30µm.

[0011] According to some embodiments of this utility model, a plane perpendicular to the width direction of the squeegee blade is defined as a reference plane, and the projection of the notch on the reference plane is a triangle.

[0012] According to some embodiments of this utility model, a plane perpendicular to the width direction of the squeegee blade is defined as a reference plane, and the projection of the notch on the reference plane is a rectangle.

[0013] According to some embodiments of this utility model, a plane perpendicular to the width direction of the squeegee blade is defined as a reference plane, and the projection of the notch on the reference plane is a semi-circle.

[0014] According to some embodiments of this utility model, the doctor blade is made of plastic, metal, or rubber.

[0015] According to some embodiments of the present invention, the plurality of the notches are arranged at equal intervals.

[0016] A flexographic printing system according to a second aspect of the present invention includes: an ink fountain; an anilox roller, a portion of which is disposed within the ink fountain; and a doctor blade as described in the above embodiment, wherein the doctor blade is disposed against the outer side wall of the anilox roller, and the length direction of the doctor blade is parallel to the axial direction of the anilox roller.

[0017] The flexographic printing system according to the embodiments of the present invention has at least the following beneficial effects:

[0018] When the doctor blade of this invention scrapes ink onto the outer wall of the anilox roller, the cells are filled with ink, and ink lines are left on the surface of the cell wall. It is easy to understand that compared with the effect of traditional doctor blades scraping ink on the anilox roller, the doctor blade of this invention produces many ink lines on the entire surface of the anilox roller. These ink lines protrude from the roller surface of the anilox roller, connect the ink in the cells, and increase the amount of ink transferred. Therefore, when the ink is transferred to the solid area of ​​the flexographic printing plate, it is easier to level than the traditional ink application method. Due to the increased amount of ink, the smoothness and saturation of the ink are higher, so the final visual effect gives people a strong sense of thickness, which greatly improves the expressiveness of solid colors in flexographic printing.

[0019] According to some embodiments of the present invention, the axial direction of the anilox roller is parallel to the horizontal plane.

[0020] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 This is a schematic diagram of the structure of a flexographic printing system;

[0023] Figures 2 to 4 A side view of a traditional doctor blade;

[0024] Figure 5 This is a front view of a traditional doctor blade.

[0025] Figure 6 This diagram illustrates the traditional combination of doctor blade, anilox roller, and ink fountain.

[0026] Figure 7 This is a magnified view of a portion of the anilox roller;

[0027] Figures 8 to 10 This is a side view of the doctor blade according to several embodiments of the present invention;

[0028] Figures 11 to 13 This is a front view of the doctor blade according to several embodiments of the present invention;

[0029] Figure 14 This is a diagram showing the assembly of the doctor blade, anilox roller, and ink fountain according to an embodiment of the present invention.

[0030] Figure 15 This is a diagram showing the assembly of the doctor blade and anilox roller according to an embodiment of the present invention;

[0031] Figure 16 This is a partially enlarged view of an anilox roller according to an embodiment of the present invention.

[0032] Icon labels:

[0033] 10. Printing substrate; 20. Ink; 30. Ink lines;

[0034] 100. Ink line;

[0035] 200. Anilox roller; 210. Cell; 220. Mesh wall;

[0036] 300. Squeegee; 310. Squeegee blade; 320. Blade; 311. Notch;

[0037] 400. Printing plate cylinder;

[0038] 500. Flexographic printing plate;

[0039] 600. Imprinting cylinder;

[0040] 700. Drying equipment;

[0041] 800, First guide roller;

[0042] 900, Second guide roller. Detailed Implementation

[0043] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0044] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] Currently, mainstream printing methods include offset printing, gravure printing, screen printing, flexographic printing, and digital printing. For packaging products, offset and gravure printing are the primary methods, while flexographic printing is mainly used in the labeling field. In recent years, flexographic printing has also been expanding into the packaging industry. Its core advantages lie in its environmental friendliness, production efficiency, and cost control. It is suitable for products with high environmental requirements, such as food, pharmaceuticals, and cigarettes. Its characteristics include thick and vibrant colors, and it can use water-based and UV inks. However, due to limitations in plate materials and plate making, its dot printing is not as fine as offset printing. Therefore, in current applications, it is mostly used for printing solid colors and lines. The basic principles of flexographic printing are as follows: Figure 1 As shown, the ink fountain 100 is used to load ink, the flexographic printing plate 500 is mounted on the printing plate cylinder 400, and various graphics to be printed are made on the flexographic printing plate 500. The printing substrate 10 is covered on the impression cylinder 600. After the doctor blade 300 scrapes off the surface ink 20, the anilox roller 200 transfers the ink 20 in the cells 210 to the graphic area on the flexographic printing plate 500. Then, under slight pressure, the ink 20 in the graphic area of ​​the flexographic printing plate 500 is transferred to the surface of the printing substrate 10. After drying by the drying device 700, the single-color flexographic printing is completed. The first guide roller 800 and the second guide roller 900 are used to keep the printing substrate 10 in a taut state.

[0047] Flexographic printing is a wet-on-dry printing method, significantly different from offset printing but similar to gravure printing. Traditional offset printing equipment is complex and difficult to operate, while gravure printing equipment is bulky and uses solvent-based inks, which are extremely environmentally unfriendly. Flexographic printing, on the other hand, has a simpler structure and its process combinations are far superior to both offset and gravure printing. Among existing printing methods, offset printing produces excellent dot effects, followed by flexographic printing, while gravure printing is relatively coarse. In solid color printing, gravure printing, due to the use of solvent-based inks, has excellent leveling properties, flexographic printing produces thicker ink, while offset printing produces poorer solid colors, often requiring multi-color overprinting. Therefore, flexographic printing, in both dot and solid color printing, is at the middle level among the three major printing methods. When flexographic printing is applied to packaging, there is a high demand for solid color printing, where the smoothness of the solid colors and the leveling properties of the ink become crucial. Compared to gravure printing, gravure printing, due to its use of solvent-based inks, has excellent leveling properties. Furthermore, gravure printing produces a thicker ink layer, resulting in excellent solid color printing effects. Flexographic printing requires an anilox roller 200 to transfer ink onto the flexographic plate, resulting in slightly less ink transfer compared to gravure printing. Flexographic inks are mostly water-based or UV inks, and their flowability is also worse than solvent-based inks. The ink transfer via the anilox roller 200 in flexographic printing... Figure 6 , Figure 7As shown, there are various structures for the cell 210. Taking the commonly used hexagonal cell 210 as an example, it can be seen from the figure that the surface of the screen wall 220 on the anilox roller 200 does not have ink 20 before passing through the doctor blade 300. After passing through the doctor blade 300, the ink 20 on the surface of the screen wall 220 is scraped off by the doctor blade, while the ink 20 inside the cell 210 is retained and can be transferred to the flexographic printing plate 500. In this way, the ink 20 that is first transferred to the surface of the flexographic printing plate 500 is initially in the state of interspersed dots 20, which are not connected to each other. It takes a certain amount of time to level out. If the surface properties of the substrate 10 are slightly poor, it will affect the flatness of the solid printing. The reason why the ink 20 on the screen wall 220 of the anilox roller 200 is scraped clean is due to the traditional doctor blade 300 structure. There are roughly three types of traditional doctor blade 300 structures, such as... Figures 2 to 5 As shown, their shapes are different, but they all have the common feature that the doctor blades 310 are straight. This results in the ink 20 actually being transferred from the anilox roller 200 to the surface of the flexographic printing plate 500 in a dotted distribution with gaps between each other. Leveling takes time, which affects the printing speed and solid printing effect. This effect is especially obvious for water-based and UV inks 20 with high viscosity.

[0048] like Figures 8 to 13 As shown, the present application provides a doctor blade 300, which is applied in a flexographic printing system. The doctor blade 300 includes a blade body 320 and a doctor blade 310. The doctor blade 310 is connected to the blade body 320 and has a plurality of notches 311 spaced apart along the length direction of the doctor blade 310.

[0049] Understandably, the doctor blade 310 is connected to one side of the blade body 320. Multiple notches 311 arranged at intervals along the length direction of the doctor blade 310 can be formed on the doctor blade 310 by mechanical, laser or other processing methods. It should be noted that when the doctor blade 300 is applied to a flexographic printing system, the doctor blade 310 is set against the outer wall of the anilox roller 200, and the length direction of the doctor blade 310 is parallel to the axial direction of the anilox roller 200.

[0050] like Figures 14 to 16As shown, when the doctor blade 300 of this invention scrapes ink onto the outer wall of the anilox roller 200, the cells 210 are filled with ink 20, and ink lines 30 are left on the surface of the screen wall 220. It is easy to understand that compared with the effect of traditional doctor blades scraping ink on the anilox roller 200, the doctor blade 300 of this invention produces many ink lines 30 on the entire surface of the anilox roller 200 after scraping ink. These ink lines 30 protrude from the roller surface of the anilox roller 200 and make the ink 20 in the cells 210 interconnected, and increase the amount of ink transferred. Therefore, when the ink 20 is transferred to the solid area of ​​the flexographic printing plate, it is easier to level than the traditional ink application method. Due to the increased amount of ink, the smoothness and saturation of the ink 20 are higher, so the final visual effect gives people a strong sense of thickness, which greatly improves the expressiveness of solid colors in flexographic printing.

[0051] like Figure 11 As shown, furthermore, the width of the notch 311 is W, satisfying: 10µm≤W≤30µm; wherein, the width direction of the notch 311 is the same as the length direction of the doctor blade 310. The value of the width W of the notch 311 can be 10µm, 12µm, 14µm, 16µm, 18µm, 20µm, 22µm, 24µm, 26µm, 28µm, or 30µm, but is not limited to those described above.

[0052] Understandably, if W < 10µm, the ink lines 30 are too thin and easily break, failing to form continuous channels. If W > 30µm, excessive ink residue 20 causes the ink lines 30 to fuse together, damaging the cell boundaries 210 and resulting in ink smearing and dot gain.

[0053] In some embodiments, the depth of the notch 311 is D, satisfying: 5µm ≤ D ≤ 15µm; wherein the depth direction of the notch 311 is perpendicular to the length direction and the thickness direction of the doctor blade 310. The value of the depth D of the notch 311 can be 5µm, 6µm, 7µm, 8µm, 9µm, 10µm, 11µm, 12µm, 13µm, 14µm, or 15µm, but is not limited to those described above.

[0054] Furthermore, the interval H between two adjacent notches 311 along the length direction of the squeegee blade 310 satisfies: 10µm≤H≤30µm. The value of the interval H between two adjacent notches 311 can be 10µm, 12µm, 14µm, 16µm, 18µm, 20µm, 22µm, 24µm, 26µm, 28µm, or 30µm, but is not limited to those described above.

[0055] It is understandable that if the spacing H is too small, the ink lines 30 will be dense, and the superposition of the fluidity of ink 20 will cause ink overflow. If H > 30µm, the ink lines 30 cannot be effectively bridged, and the leveling acceleration effect will be reduced.

[0056] It should be noted that the width W of the notch 311 can be greater than the interval H between two adjacent notches 311, or it can be less than the interval H between two adjacent notches 311.

[0057] In some embodiments, the multiple notches 311 are arranged at equal intervals. Of course, in other embodiments, the multiple notches 311 may also be arranged at non-equal intervals.

[0058] like Figures 11 to 13 As shown, a plane perpendicular to the width direction of the squeegee blade 310 is defined as a reference plane, and the projection of the notch 311 onto the reference plane is a triangle, a rectangle, or a semicircle. Of course, in other embodiments, the shape of the notch 311 can be other shapes.

[0059] Combination Figure 1 , Figure 11 and Figure 14 The present invention also provides a flexographic printing system, including: an ink fountain 100, an anilox roller 200, and a doctor blade 300 as described in the above embodiments.

[0060] The anilox roller 200 is partially located in the ink fountain 100.

[0061] Specifically, the anilox roller 200 has a horizontal structure, meaning that the axis of the anilox roller 200 is basically parallel to the horizontal plane, and the bottom of the anilox roller 200 extends into the ink fountain 100, where the ink 20 can adhere to the bottom of the anilox roller 200.

[0062] The doctor blade 310 is attached to the outer side wall of the anilox roller 200, and the length direction of the doctor blade 310 is parallel to the axial direction of the anilox roller 200.

[0063] like Figures 14 to 16As shown, when the doctor blade 300 of this invention scrapes ink onto the outer wall of the anilox roller 200, the cells 210 are filled with ink 20, and ink lines 30 are left on the surface of the screen wall 220. It is easy to understand that compared with the effect of traditional doctor blades scraping ink on the anilox roller 200, the doctor blade 300 of this invention produces many ink lines 30 on the entire surface of the anilox roller 200 after scraping ink. These ink lines 30 protrude from the roller surface of the anilox roller 200 and make the ink 20 in the cells 210 interconnected, and increase the amount of ink transferred. Therefore, when the ink 20 is transferred to the solid area of ​​the flexographic printing plate, it is easier to level than the traditional ink application method. Due to the increased amount of ink, the smoothness and saturation of the ink 20 are higher, so the final visual effect gives people a strong sense of thickness, which greatly improves the expressiveness of solid colors in flexographic printing.

[0064] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A doctor blade, used in a flexographic printing system, characterized in that, include: Blade; A scraping blade is connected to the blade body. The scraping blade has multiple notches spaced apart along the length of the scraping blade. The width of the notches is W, which satisfies the following condition: 10µm≤W≤30µm. The width direction of the notch is the same as the length direction of the squeegee blade.

2. The doctor blade according to claim 1, characterized in that, The depth of the notch is D, which satisfies: 5µm≤D≤15µm; wherein, the depth direction of the notch is perpendicular to the length direction of the doctor blade and the thickness direction of the doctor blade.

3. The doctor blade according to claim 1, characterized in that, The interval between two adjacent notches arranged along the length direction of the scraping blade is H, which satisfies: 10µm≤H≤30µm.

4. The doctor blade according to claim 1, characterized in that, Define a plane perpendicular to the width direction of the squeegee blade as a reference plane, and the projection of the notch onto the reference plane is a triangle.

5. The doctor blade according to claim 1, characterized in that, Define a plane perpendicular to the width direction of the squeegee blade as a reference plane, and the projection of the notch onto the reference plane is a rectangle.

6. The doctor blade according to claim 1, characterized in that, Define a plane perpendicular to the width direction of the squeegee blade as a reference plane, and the projection of the notch onto the reference plane is a semicircle.

7. The doctor blade according to claim 1, characterized in that, The doctor blade is made of plastic, metal, or rubber.

8. The doctor blade according to claim 1, characterized in that, The multiple gaps are arranged at equal intervals.

9. A flexographic printing system, characterized in that, include: Ink line; An anilox roller, part of which is located inside the ink fountain; The doctor blade according to any one of claims 1 to 8, wherein the doctor blade is disposed in contact with the outer side wall of the anilox roller, and the length direction of the doctor blade is parallel to the axial direction of the anilox roller.

10. The flexographic printing system according to claim 9, characterized in that, The axial direction of the anilox roller is parallel to the horizontal plane.

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