Printing sheet with 3D expansion effect, preparation method of printing sheet and packaging hose

Abstract

The invention discloses a printing sheet with a 3D expansion effect, a preparation method of the printing sheet and a packaging hose. According to the preparation method, an optical basic principle is converted into a visual effect principle, printing, copying and restoring are finally converted into proportion matching and dot shape design of artwork dots, then a finally designed file is transmitted to a digital plate making machine for laser engraving, and manufacturing of a printing plate material is completed. And then the multi-color dots are transferred to the printing blank base material through the printing process technologies such as flexographic printing, letterpress printing or offset printing, so that the printed pattern forms a 3D expansion effect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of printing and hose packaging, and particularly relates to a printed sheet with 3D stereoscopic expansion effect and a preparation method thereof and a packaging hose. BACKGROUND

[0002] The existing printed products adopt conventional arrangement directions of printing dots, different proportional dot distributions, different color dot superposition technologies, and dot shapes. The conventional printing dot distribution can only display color depth, and the dot superposition of different colors presents different color levels. The existing printed products are in the 2D plane dimension, and it is difficult to reflect the stereoscopic effect of the real world. In order to make the appearance of the packaging product more attractive, the design of the pattern on the packaging appearance is more inclined to design the 3D stereoscopic effect. Most of the existing printing processes can only realize the 3D stereoscopic effect through silk printing or photoetching laser stamping and other high-cost schemes. The existing photoetching technology realizes the 3D stereoscopic effect by additional physical increase of a coating layer from the outside of the printed product or directional refraction grading change of light path on the nanoscale coating layer. However, the preparation of the existing 3D stereoscopic effect printed product has completely exceeded the range that can be realized by the printing process itself, and it is difficult to reduce the cost and production cycle, which is not conducive to large-scale promotion by the end customer, and it is difficult to keep up with the changes in customer demand in the rapidly changing packaging market. Based on the above reasons, it is urgent to develop a printing process technology with low cost and simplified process route to meet the technical demand of the printed product appearance with 3D stereoscopic effect. SUMMARY

[0003] In order to overcome the deficiencies and shortcomings of the prior art, the primary purpose of the present application is to provide a preparation method of a printed sheet with 3D stereoscopic expansion effect. The preparation method realizes the visual stereoscopic effect of the printed sheet through special dot calculation distribution design and composite dot printing mode. The special dot calculation distribution design refers to deriving a new dot arrangement mode and manufacturing method for the dot distribution of a plane pattern through a special optical refraction principle algorithm formula, so that the printed pattern forms a 3D stereoscopic expansion effect.

[0004] The second purpose of the present application is to provide a printed sheet with 3D stereoscopic expansion effect prepared by the above preparation method.

[0005] The third purpose of the present application is to provide a packaging hose with 3D stereoscopic expansion effect.

[0006] The primary purpose of the present application can be achieved by the following technical scheme: A preparation method of a printed sheet with 3D stereoscopic expansion effect, comprising the following steps, (1) The arrangement and proportion distribution of special dot shapes: the designed planar pattern is arranged and superimposed by different dots through different dot shapes by deconstructing optical principles, and the printed pattern arranged by special dot shapes presents a visual bulging effect through the arrangement and proportion distribution of special dot shapes (preset arrangement and proportion distribution of dot shapes); (2) Obtaining the final designed file data: the arrangement and proportion distribution of special dot shapes in step (1) are repeatedly modified on a blank sheet through digital printing simulation technology (soft proofing) to obtain the required digital printing dot shape arrangement and proportion distribution, that is, the final designed digital file data (ICC file); (3) Compound dot printing method: the final designed digital file data (ICC file) in step (2) is transmitted to a digital plate making machine to obtain a physical printing plate, and then the blank sheet is printed to obtain a printed sheet with a 3D bulging effect; The specific way of arranging and superimposing different colors through different dot shapes in step (1) is, First, according to the refraction and reflectivity formula of light, the range of the refractive index and reflectivity coefficient of the pigments used on the substrate is determined, and Snell's Law is applied, the formula is as follows: n1 * sin(θ1) = n2 * sin(θ2) Where, · n1, n2: the refractive index of two media respectively, · θ1, θ2: the incident angle and the refractive angle (angle relative to the normal) respectively, Reflectivity R is defined as the ratio of reflected light power to incident light power, Fresnel equation gives the reflection coefficient (amplitude ratio) r, and reflectivity R is the square of the reflection coefficient; The simplified algorithm of light perpendicular to the interface is adopted: R = |r|² = | (n1 - n2) / (n1 + n2) |²; Then, according to the perception of light and dark by the human eye or densitometer, optical density D is introduced to quantify the ink layer concentration of the solid printed pattern, $$ D_{solid} = -\log_{10}(R_{solid}) $$, where $R_{solid}$ is the reflectivity measured under a certain measurement state; Finally, according to the obtained physical dot coverage (a) and optical density (D tint), the arrangement and proportion distribution of the special dot shape are obtained by combining the Murray-Davis and Yule-Nielsen formulas; The Murray-Davis formula is a theoretical formula directly connecting the dot density and dot coverage under the ideal state under the condition of linear optical effect, and the specific formula is $a$ = \frac{1 - 10^{-D_{tint}}}{1 - 10^{-D_{solid}}}} \times 100% $; The Yule-Nielsen formula introduces a correction factor n to simulate the nonlinear optical effect on the basis of the Murray-Davis formula, and the specific formula is$$ a = \frac{1 - 10^{-D_{tint} / n}}{1 - 10^{-D_{solid} / n}} \times 100% $$, Wherein, n is an empirical value (usually 1<n<= 2); The process flow of the physical dot shape and distribution proportion on the printing plate in step (3) sequentially goes through back exposure, laser processing, main exposure, plate washing, drying, debonding and post-exposure procedures; the power of the back exposure is 3KW, and the time of the back exposure is 10-15 seconds; the power of the laser processing is 600W, the laser processing mode is engraving, and the time of the laser processing is 20-40 minutes (depending on the pattern area); the power of the main exposure is 5KW, and the time of the main exposure is 350-400 seconds; the temperature of the plate washing is 75℃, and the time of the plate washing is 360-420 seconds; the temperature of the drying is 70℃, and the time of the drying is 350-450 seconds; the debonding power is 2KW (UVA exposure), and the debonding time is 160-180 seconds; the post-exposure power is 2KW (UVB exposure), and the time of the post-exposure power is 250-300 seconds.

[0007] Preferably, the final designed digital file data (ICC file) in step (2) is generated according to the following specific process: according to the required pattern printing test paper, print a standard color target such as IT8.7 / 4; use a spectrophotometer to read the color and measure the color data; generate an ICC characteristic file through professional software calculation; output the ICC file; apply the obtained ICC file, embed or specify the ICC file in the design software, and call the corresponding ICC file for color conversion during printing.

[0008] Preferably, the thickness of the blank sheet in step (2) is 0.20-0.50mm.

[0009] Preferably, the blank sheet in step (2) is one of the following: all-plastic sheet, aluminum-plastic sheet, or high-gloss sheet.

[0010] Preferably, the back exposure power is 3KW, the back exposure time is 10 seconds, the laser processing power is 600W, the laser processing method is engraving, the laser processing time is 20 minutes (depending on the pattern area), the main exposure power is 5KW, the main exposure time is 350 seconds, the plate washing temperature is 75℃, the plate washing time is 360 seconds, the drying temperature is 70℃, the drying time is 350 seconds, the de-adhesion power is 2KW (UVA exposure), the de-adhesion time is 160 seconds, the post-exposure power is 2KW (UVB exposure), and the post-exposure time is 250 seconds.

[0011] Preferably, the back exposure power is 3KW, the back exposure time is 12 seconds, the laser processing power is 600W, the laser processing method is engraving, the laser processing time is 30 minutes (depending on the pattern area), the main exposure power is 5KW, the main exposure time is 380 seconds, the plate washing temperature is 75℃, the plate washing time is 400 seconds, the drying temperature is 70℃, the drying time is 400 seconds, the de-adhesion power is 2KW (UVA exposure), the de-adhesion time is 170 seconds, the post-exposure power is 2KW (UVB exposure), and the post-exposure time is 300 seconds.

[0012] Preferably, the back exposure power is 3KW, the back exposure time is 15 seconds, the laser processing power is 600W, the laser processing method is engraving, the laser processing time is 40 minutes (depending on the pattern area), the main exposure power is 5KW, the main exposure time is 400 seconds, the plate washing temperature is 75℃, the plate washing time is 420 seconds, the drying temperature is 70℃, the drying time is 450 seconds, the de-adhesion power is 2KW (UVA exposure), the de-adhesion time is 180 seconds, the post-exposure power is 2KW (UVB exposure), and the post-exposure time is 300 seconds.

[0013] Preferably, the thickness of the printing plate substrate in step (3) is 0.45~0.50mm.

[0014] Preferably, the printing method in step (3) is flexographic printing, letterpress printing, or offset printing.

[0015] The second objective of this invention can be achieved through the following technical solution: A printing sheet with a 3D stereoscopic expansion effect is prepared by the above-described preparation method.

[0016] The third objective of this invention can be achieved through the following technical solution: A packaging tube with a 3D three-dimensional expansion effect includes a tube head and a tube body, wherein the tube body is made by welding the aforementioned printed sheet with a 3D three-dimensional expansion effect.

[0017] Preferably, the tube is cylindrical or polygonal.

[0018] Preferably, the polygon is one of a rectangle, a square, or a triangle.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The method for preparing the printed sheet with 3D stereoscopic expansion effect described in this invention is an improvement on the existing 2D printing process. The printing file is processed with halftone dots to change the gradient change of the halftone dots to the angle of refraction of incident light, so that the optical path of the eyes changes, causing a visual time difference between the two eyes, thereby producing a visual stereoscopic expansion effect. This technology, through a deep understanding of optical principles, flexibly uses the gradient change of halftone dot distribution to the angle of light incident and the refraction path, and through precise calculation and scientific testing, has yielded a high-performance, comprehensive improvement method for preparing the printed sheet with 3D stereoscopic expansion effect. (2) This invention utilizes a special dot arrangement calculation method, and through the deconstruction optical principle, different colors in the designed pattern are arranged and superimposed through different dot offsets, and the specially arranged dots present a visual expansion and protrusion effect; (3) Different dot shapes refract light differently. By utilizing the difference in refraction, the human visual system can be stimulated to produce a three-dimensional protrusion of gray levels. Combined with the superposition of different colors, it gives the effect of expansion and protrusion and a realistic texture. (4) By designing special dots and adjusting plate-making parameters, special dot arrangement printing patterns are formed. The visual three-dimensional effect is achieved through printing methods such as flexographic printing and offset printing. Compared with existing methods such as screen printing, photolithography, and embossing, which physically thicken the coating or change the surface morphology, the printing sheet with 3D three-dimensional expansion effect described in this invention has a wider range of application scenarios and a more competitive cost advantage. Attached Figure Description

[0020] Figure 1 This is a front view of the packaging tube prepared in Example 1; Figure 2 This is a back view of the packaging tube prepared in Example 1; Figure 3 This is a magnified schematic diagram of the halftone dots at 3% and 4% in Example 1; Figure 4 This is a magnified schematic diagram of the halftone dots at 14% and 15% in Example 1; Figure 5This is a magnified schematic diagram of the dots at 30% and 35% dot ratios in Example 1; Figure 6 This is a magnified schematic diagram of the dots at 45% and 50% dot ratios in Example 1; Figure 7 This is a magnified schematic diagram of the dots at 70% and 75% dot ratios in Example 1; Figure 8 This is a magnified schematic diagram of the dots at 80% and 85% dot ratios in Example 1; Figure 9 This is a magnified schematic diagram of the halftone dots at 94% and 95% in Example 1; Figure 10 These are enlarged schematic diagrams of the halftone dots at 99% and 100% in Example 1; Figure 11 This is a magnified schematic diagram of the multi-color overprinted halftone dots in the expansion effect area of ​​Example 1; Figure 12 This is a magnified schematic diagram of the black grayscale dots in the expansion effect area of ​​Example 1; Figure 13 To generate the desired ICC (International Color Consortium) profile after achieving the expected effect in Example 1; Figure 14 This is a front view of the packaging tube prepared in Example 2; Figure 15 This is a back view of the packaging tube prepared in Example 2; Figure 16 This is a front view of the packaging tube prepared in Example 3; Figure 17 This is a back view of the packaging tube prepared in Example 3; Figure 18 Design original comparison charts for different document sample halftone ratios and expansion effects; Figure 19 A comparison image of a 2D planar design and a corresponding 3D stereoscopic expansion effect printed sheet. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. All materials used in the examples of the present invention are commercially available.

[0022] Example 1 The method for preparing the printed sheet with 3D stereoscopic expansion effect described in this embodiment includes the following preparation steps: (1) Arrangement and proportional distribution of special dot shapes: The designed planar pattern is arranged and superimposed with different colors through different dot offsets using the principle of deconstruction optics. Through the arrangement and proportional distribution of special dot shapes (preset dot shape arrangement and proportional distribution), the dot arrangement printed pattern presents a visual expansion and protrusion effect. (2) Obtain the final designed file data: The arrangement and proportion of the special dot shapes in step (1) are repeatedly modified by digital printing simulation technology (soft proofing) and the color space is replicated on blank sheet to obtain the arrangement and proportion of the dot shapes that meet the actual digital printing requirements of the design, that is, the final designed digital file data (ICC file). (3) Composite dot printing method: The final digital file data (ICC file) designed in step (2) is transmitted to the digital plate making machine for laser engraving to obtain a physical printing plate. Then, the blank sheet is printed by flexographic printing, letterpress printing or offset printing to prepare a printing sheet with 3D stereoscopic expansion effect.

[0023] In this embodiment, step (1) is carried out as follows: The present invention analyzes the human eye’s perception principle of pattern stereoscopic vision, the most important of which is the direction of light and the shadow cast by the light on the object, forming the visual perception of the object’s protrusion and depression.

[0024] Preferably, the specific method by which the deconstruction optics principle described in step (1) arranges and superimposes different colors through different dot offsets is as follows: First, determine the range of refractive index and reflectance of the pigment we use on the substrate based on the formulas for refraction and reflectance of light, applying Snell's Law, as follows: n1 * sin(θ1) = n2 * sin(θ2) in, • n1, n2: are the refractive indices of the two media, respectively; • θ1, θ2: These are the angle of incidence and the angle of refraction (angles relative to the normal), respectively. Reflectivity R is defined as the ratio of reflected light power to incident light power. The Fresnel equation gives the reflection coefficient (amplitude ratio) r, and reflectivity R is the square of the reflection coefficient. A simplified algorithm is used to illuminate the interface perpendicularly: R = |r|² = | (n1 - n2) / (n1 + n2) |²; Then, based on the human eye's or densitometer's perception of brightness and darkness (which is not linear but logarithmic), optical density $D$ is introduced to quantify the ink layer concentration of the solid area of ​​the printed pattern, $$ D_{solid} = -\log_{10}(R_{solid}) $$ , where $R_{solid}$ is the reflectance measured in a certain measurement state (such as state T); The significance of density value $D$: It directly reflects the ink's ability to absorb light, and this absorption ability is rooted in the pigment's extinction coefficient κ. The higher the $D$ value, the thicker or more concentrated the ink is, the more light it absorbs and the lower its reflectivity.

[0025] Then, moving from the solid area to the halftone area, because the printed image is composed of halftone dots of different sizes. Within a halftone unit, part is ink (with a reflectance of $R_{solid}$) and part is substrate (with a reflectance of $R_{paper}$).

[0026] • Physical network coverage (a): refers to the actual proportion of network outlets per unit area; • Optical density (D tint): The density value obtained by measuring the entire dot area; Finally, based on the obtained physical dot coverage (a) and optical density (D tint), and combined with the Murray-Davis and Yule-Nielsen formulas, the arrangement and proportional distribution of special dot shapes are obtained; The Murray-Davis formula is a theoretical formula that directly connects dot density and dot coverage under ideal conditions under linear optical effects. The specific formula is $a$ = \frac{1 - 10^{-D_{tint}}}{1 -10^{-D_{solid}}}} \times 100% $$; This formula links macroscopic measurements ($D_{tint}$ and $D_{solid}$) to physical parameters (network coverage $a$); The Yule-Nielsen formula is based on the Murray-Davis formula, but with the addition of a correction factor `n` to simulate nonlinear optical effects. The specific formula is $$ a = \frac{1 - 10^{-D_{tint} / n}}{1 - 10^{-D_{solid} / n}} \times 100% $$, The meaning of the factor `n`: n is an empirical value (usually 1). <n<= 2)。

[0027] The `n` factor encompasses all complex optical interactions, including: a. The light scattering properties of the substrate (determined by the substrate's refractive index and microstructure); b. Multiple reflections and refractions of light in the ink dots and substrate; c. Essentially, the `n` factor incorporates the scattering properties of the substrate (which are themselves determined by its refractive index and structure) into the computational model.

[0028] The specific steps of step (2) in this embodiment are as follows: By summarizing and calculating the data relationship between the density and percentage (coverage) of all dots in the pattern, and performing soft proofing on blank sheets, the relevant parameters of the dots (dot shape, percentage, etc.) are adjusted. This process is repeatedly compared and modified with the target effect to obtain the arrangement and proportion of dot shapes that meet the actual digital printing requirements of the design. Finally, the final designed file data (ICC file) is obtained, i.e., the ICC (International Color Consortium) profile of the desired effect is generated after achieving the expected result (see the ICC file generation process). Figure 13 ),like Figures 3 to 10 This is a magnified view of the halftone dots at different ratios, which have been repeatedly modified and adjusted during the soft proofing process, such as... Figure 11 A magnified diagram of multi-color overprinted halftone dots in the area of ​​expansion effect; Figure 12 This is a magnified diagram of the black and grayscale dots in the area of ​​the expansion effect, as shown below. Figure 13 The diagram shows the ICC (International Color Consortium) profile generated after achieving the desired effect (ICC file generation flowchart). This step, which transforms the dot density structure of the pattern into actual dot transfer and replication in the printing process, involves applying the dot shape and proportion distribution data obtained from theoretical formulas to the specific color artwork to be designed. Then, the dot shape and proportion distribution on the color artwork are converted into an ICC file for plate making, subsequent engraving, and finally, production on the printing press to achieve actual dot transfer and replication. The dot density is the quantitative value of optical density measured by an optical densitometer. The dot density in the ICC file is data marked and quantitatively adjusted using the percentage values ​​of specific dots. The specific process for generating the ICC file is as follows: Print a standard color target such as IT8.7 / 4 according to the required pattern printing test draft; read the color using a spectrophotometer and measure the color data; calculate and generate the ICC characteristic file using professional software; output the ICC file; apply the obtained ICC file, embed or specify the ICC file in the design software, and call the corresponding ICC file for color conversion during printing.

[0029] The thickness of the blank sheet is 0.50 mm; The blank sheet is an all-plastic sheet; The specific steps of step (3) in this embodiment are as follows: The ICC file obtained in step (2) above is transmitted to a digital plate-making machine for laser engraving to obtain a physical printing plate. Then, the printing substrate is printed using flexographic or offset printing methods to prepare a printed sheet with a 3D stereoscopic expansion effect, such as... Figure 13 This is a magnified diagram showing multi-color overprinted halftone dots in the area of ​​the expansion effect. Figure 14 This is a magnified diagram of the black grayscale dots in the area of ​​the expansion effect.

[0030] The process flow for determining the dot shape and distribution ratio on the physical printing plate described in step (3) involves back exposure, laser processing, main exposure, plate washing, drying, de-adhesion, and post-exposure. The power of the back exposure is 3KW, and the exposure time is 12 seconds. The power of the laser processing is 600W, the laser processing method is engraving, and the laser processing time is 30 minutes (depending on the pattern area). The power of the main exposure is 5KW, and the exposure time is 380 seconds. The plate washing temperature is 75℃, and the washing time is 400 seconds. The drying temperature is 70℃, and the drying time is 400 seconds. The de-adhesion power is 2KW (UVA exposure), and the de-adhesion time is 170 seconds. The power of the post-exposure is 2KW (UVB exposure), and the exposure time is 300 seconds. The thickness of the printing plate is 0.45mm.

[0031] The back exposure process specifically involves exposing and curing the back of the printing plate to increase its strength and make it more suitable for the transfer of halftone inks. The laser processing process specifically involves laser engraving of the printing plate surface dot by dot according to the digital ICC file description to form the halftone pattern. The main exposure process specifically involves exposing the halftone pattern again in the full wavelength range after the pattern engraving is completed, so that the halftone pattern has high curing strength and ensures printing quality. The plate washing process specifically involves spraying water through a nozzle to retain the pattern part and remove the non-pattern parts. The drying process specifically involves removing moisture. The de-adhesion process specifically involves using a rubber roller to roll and press the surface of the printing plate to remove the residual photosensitive emulsion. The post-exposure process specifically involves enhancing the exposure of the treated printing plate to make the hardness of the front and back of the printing plate consistent, the shrinkage rate stable, and the printing durability improved.

[0032] like Figure 1 and Figure 2The images show the front and back views of the packaging tube prepared in this embodiment. The packaging tube prepared in this embodiment includes a tube head and a tube body. The tube body is made by welding the aforementioned printed sheet with a 3D three-dimensional expansion effect. The tube body in this embodiment is cylindrical, but it can also be rectangular, square, or triangular, etc.

[0033] Example 2 The difference between the preparation method of the printing sheet with 3D stereoscopic expansion effect described in this embodiment and that in embodiment 1 is that the designed pattern is different and the corresponding adjusted dot ratio is different. Other preparation steps are the same as in embodiment 1. The process flow of the dot shape and distribution ratio on the physical printing plate described in step (3) goes through back exposure, laser processing, main exposure, plate washing, drying, de-adhesion and post-exposure processes in sequence. The back exposure power is 3KW, the back exposure time is 10 seconds, the laser processing power is 600W, the laser processing method is engraving, the laser processing time is 20 minutes (depending on the pattern area), the main exposure power is 5KW, the main exposure time is 350 seconds, the plate washing temperature is 75℃, the plate washing time is 360 seconds, the drying temperature is 70℃, the drying time is 350 seconds, the de-adhesion power is 2KW (UVA exposure), the de-adhesion time is 160 seconds, the post-exposure power is 2KW (UVB exposure), the post-exposure time is 250 seconds, and the printing plate thickness is 0.45mm.

[0034] like Figure 14 and Figure 15 The images show the front and back views of the packaging tube prepared in this embodiment. The packaging tube prepared in this embodiment includes a tube head and a tube body. The tube body is made by welding the aforementioned printed sheet with a 3D three-dimensional expansion effect. The tube body in this embodiment is cylindrical, but it can also be rectangular, square, or triangular, etc.

[0035] Example 3 The difference between the preparation method of the printing sheet with 3D stereoscopic expansion effect described in this embodiment and that in Embodiment 1 is that the designed pattern is different and the corresponding adjustment of the dot ratio is different. Other preparation steps are the same as in Embodiment 1. The process flow of the dot shape and distribution ratio on the physical printing plate in step (3) goes through back exposure, laser processing, main exposure, plate washing, drying, de-adhesion and post-exposure processes in sequence. The power of the back exposure is 3KW and the back exposure time is 15 seconds. The power of the laser processing is 600W. The laser processing method is engraving. The laser processing time is 40 minutes (depending on the pattern area). The power of the main exposure is 5KW and the main exposure time is 400 seconds. The plate washing temperature is 75℃ and the plate washing time is 420 seconds. The drying temperature is 70℃ and the drying time is 450 seconds. The de-adhesion power is 2KW. (UVA exposure), the de-adhesion time is 180 seconds, the power of the subsequent exposure is 2KW (UVB exposure), the power of the subsequent exposure time is 300 seconds, and the thickness of the printing plate is 0.50mm.

[0036] The difference between this embodiment and Embodiment 1 is that the designed pattern is different, and the adjusted dot ratio is also different. Figure 16 and Figure 17 The images show the front and back views of the packaging tube prepared in this embodiment. The packaging tube prepared in this embodiment includes a tube head and a tube body. The tube body is made by welding the aforementioned printed sheet with a 3D three-dimensional expansion effect. The tube body in this embodiment is cylindrical, but it can also be rectangular, square, or triangular, etc.

[0037] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a printed sheet with a 3D stereoscopic expansion effect, characterized in that, Includes the following steps: (1) Arrangement and proportional distribution of special dot shapes: The designed planar pattern is arranged and superimposed with different colors through different dot offsets by deconstructing optical principles. Through the arrangement and proportional distribution of special dot shapes, the printed pattern with specially arranged dot patterns presents a visual expansion and protrusion effect. (2) Obtain the final designed file data: The arrangement and proportion of the special dot shapes in step (1) are repeatedly modified by digital printing simulation technology and the color space is replicated on blank sheet to obtain the arrangement and proportion of the dot shapes that meet the design requirements of the actual digital printing, i.e., the ICC file. (3) Composite dot printing method: The ICC file in step (2) is transferred to the digital plate making machine for laser engraving to obtain a physical printing plate. Then, the blank sheet is printed by flexographic printing, letterpress printing or offset printing to prepare a printing sheet with 3D stereoscopic expansion effect. The specific method by which the deconstruction optics principle described in step (1) arranges and superimposes different colors through different dot offsets is as follows: First, determine the range of refractive index and reflectance of the pigment on the substrate using the formulas for refraction and reflectance of light, applying Snell's law, as follows: n1 * sin(θ1) = n2 * sin(θ2) in, • n1, n2: are the refractive indices of the two media, respectively. • θ1, θ2: angle of incidence and angle of refraction, respectively. Reflectivity R is defined as the ratio of reflected light power to incident light power. The Fresnel equation gives the reflection coefficient r, and reflectivity R is the square of the reflection coefficient. A simplified algorithm is used to illuminate the interface perpendicularly: R = |r|² = | (n1 - n2) / (n1 + n2) |²; Then, based on the human eye's or densitometer's perception of brightness and darkness, optical density $D$ is introduced to quantify the ink layer concentration of the solid area of ​​the printed pattern, $$ D_{solid} = -\log_{10}(R_{solid}) $$ , where $R_{solid}$ is the reflectance measured under a certain measurement state; Finally, based on the obtained physical dot coverage (a) and optical density (D tint), combined with the Murray-Davis and Yule-Nielsen formulas, the arrangement and proportional distribution of special dot shapes are obtained; The Murray-Davis formula is a theoretical formula that directly connects dot density and dot coverage under ideal conditions of linear optical effects. The specific formula is $a$ = \frac{1 - 10^{-D_{tint}}}{1 - 10^{-D_{solid}}}} \times 100% $$; The Yule-Nielsen formula is based on the Murray-Davis formula, but with the addition of a correction factor `n` to simulate nonlinear optical effects. The specific formula is $$ a = \frac{1 - 10^{-D_{tint} / n}}{1 - 10^{-D_{solid} / n}} \times 100% $$, Where n is an empirical value, usually 1 < n <= 2; The process flow for determining the dot shape and distribution ratio on the physical printing plate described in step (3) involves back exposure, laser processing, main exposure, plate washing, drying, de-adhesion, and post-exposure. The power of the back exposure is 3KW, and the exposure time is 10-15 seconds. The power of the laser processing is 600W, the laser processing method is engraving, and the laser processing time is 20-40 minutes. The power of the main exposure is 5KW, and the exposure time is 350-400 seconds. The temperature of the plate washing is 75℃, and the washing time is 360-420 seconds. The temperature of the drying is 70℃, and the drying time is 350-450 seconds. The de-adhesion power is 2KW, and the de-adhesion time is 160-180 seconds. The power of the post-exposure is 2KW, and the exposure time is 250-300 seconds.

2. The method for preparing a printed sheet with a 3D stereoscopic expansion effect according to claim 1, characterized in that, The specific process for generating the ICC file in step (2) is as follows: Print a standard color target such as IT8.7 / 4 according to the required pattern printing test draft; read the color using a spectrophotometer and measure the color data; calculate and generate the ICC characteristic file using professional software; output the ICC file; apply the obtained ICC file, embed or specify the ICC file in the design software, and call the corresponding ICC file for color conversion during printing.

3. The method for preparing a printed sheet with a 3D stereoscopic expansion effect according to claim 1, wherein the blank sheet in step (2) is one of an all-plastic sheet, an aluminum-plastic sheet, or a high-gloss sheet.

4. The method for preparing a printed sheet with a 3D stereoscopic expansion effect according to claim 1, characterized in that, The back exposure power is 3KW, the back exposure time is 12 seconds, the laser processing power is 600W, the laser processing method is engraving, the laser processing time is 30 minutes, the main exposure power is 5KW, the main exposure time is 380 seconds, the plate washing temperature is 75℃, the plate washing time is 400 seconds, the drying temperature is 70℃, the drying time is 400 seconds, the de-adhesion power is 2KW, the de-adhesion time is 170 seconds, the post-exposure power is 2KW, and the post-exposure time is 300 seconds.

5. The method for preparing a printed sheet with a 3D stereoscopic expansion effect according to claim 1, characterized in that, The thickness of the printing plate material mentioned in step (3) is 0.45~0.50mm.

6. The method for preparing a printed sheet with a 3D stereoscopic expansion effect according to claim 1, characterized in that, The printing method described in step (3) is flexographic printing, letterpress printing, or offset printing.

7. A printed sheet with a 3D stereoscopic expansion effect, characterized in that, The printed sheet with 3D stereoscopic expansion effect is prepared according to any one of claims 1 to 6.

8. A packaging tube with a 3D three-dimensional expansion effect, characterized in that, It includes a tube head and a tube body, wherein the tube body is made by welding the printed sheet with 3D stereoscopic expansion effect as described in claim 7.

9. The packaging tube with 3D three-dimensional expansion effect according to claim 8, characterized in that, The tube body is cylindrical or polygonal.

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