A printing method for preventing white leakage at the junction of thermal transfer printing

Abstract

The present invention relates to a printing method for preventing white leakage at the junction of thermal transfer printing, comprising the following steps: S1. Color separation: extracting the color close to the color band on the manuscript; S2. Junction line identification: after the manuscript is color separated, finding the junction line between different color bands in the manuscript picture; S3. Boundary growth: dividing the printing density of the thermal transfer printer into multiple levels, and setting a high and a low density level in an alternating manner at each junction of adjacent color blocks; S4. If there is still white leakage at the thermal transfer printing, repeating steps S1 to S3 until there is no white leakage at the junction line of the thermal transfer printing. The present invention effectively reduces the white leakage at the junction of thermal transfer printing and improves the printing quality.

Description

Technical Field

[0001] The invention relates to the technical field of thermal transfer printing, in particular to a printing method for preventing white leakage at a thermal transfer printing interface. Background Art

[0002] Thermal transfer is a printing method that uses a thermal transfer machine to transfer the exquisite pattern on the transfer film to the surface of the product in one process (heating and pressurizing). After forming, the ink layer is dissolved into the surface of the product.

[0003] Whether it is traditional plate-making printing or digital printing combined with computers, accurate overprinting is only an ideal state in the printing process. In the actual production of digital printing equipment, even very small errors caused by fluctuations in paper feeding stability, deformation tension fluctuations in substrates, equipment overprinting accuracy, equipment printing accuracy, and tilt when the print head is installed will cause the substrate's base color to leak out between two adjacent objects, which is called white leakage. White leakage treatment generally uses trapping treatment, also known as white leakage, which is mainly to compensate for the white leakage between two adjacent different colors caused by inaccurate printing overprinting.

[0004] There are three main existing methods for processing white leakage. The first is not to process the image, but to enhance the mechanical precision of the printer to reduce white leakage. This method has high requirements for the design, processing and installation of the mechanical structure; the second is image scaling, which enlarges the printing area of ​​the green part by enlarging the green part, thereby eliminating white leakage. Although this method reduces white leakage, due to the characteristics of thermal transfer printers, the color of the overlapping printed area will become darker and darker, and the printing effect will be poor; the third is software trapping processing before color separation, which will cause gradual appearance of the boundary area, making the subsequent color processing more difficult, and the color of the overlapping printed area will also become darker and darker.

[0005] Therefore, those skilled in the art are committed to developing a printing method for preventing white leakage at the junction of thermal transfer printing, reducing white leakage at the junction of thermal transfer printing, and improving printing quality. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a printing method for preventing white leakage at the junction of thermal transfer printing, thereby reducing white leakage at the junction of thermal transfer printing and improving printing quality.

[0007] The technical solution of the present invention to solve the above technical problem is as follows: A printing method for preventing white leakage at the junction of thermal transfer printing, comprising the following steps:

[0008] S1. Color separation: extract the color close to the color band on the original;

[0009] S2. Boundary line recognition: After the original is separated into different colors, find the boundary lines between different color bands in the original image;

[0010] S3. Boundary growth: The printing density of the thermal transfer printer is divided into multiple levels, and the adjacent color blocks on each boundary line are alternately set with a high and a low density level;

[0011] S4. If there is still white leakage at the thermal transfer printing location, repeat steps S1 to S3 until there is no white leakage at the boundary line of the thermal transfer printing location.

[0012] The beneficial effect of the present invention is that after the boundary between different color bands is determined through color separation, a high and a low concentration level staggered with each other is set at the boundary, so that the junction is staggered and printed, avoiding white leakage at the printing boundary, thereby improving the printing quality.

[0013] Based on the above technical solution, the present invention can also be improved as follows.

[0014] Further, in step S2, if the white point of the current color layer is located at a non-white point of other color layers, and there is at least one non-white point among the eight points near the white point of the current color layer, then the white point is a boundary point, and multiple boundary points are connected to form a boundary line.

[0015] The beneficial effect of adopting the above further solution is to determine the boundary line according to the boundary point, improve the accuracy of the boundary line, and facilitate the subsequent setting of the concentration level.

[0016] Further, in step S3, the boundary lines are divided into upper boundary lines, lower boundary lines, left boundary lines and right boundary lines, wherein the concentration of the upper boundary line of the color block is greater than or equal to the optimal color rendering concentration of the color block, the concentration of the lower boundary line of the color block is less than the optimal color rendering concentration of the color block, and the growth concentrations of the left boundary line and the right boundary line of the color block are equal to the optimal color rendering concentration of the color block.

[0017] The beneficial effect of adopting the above further solution is to further subdivide according to the position of the boundary line, and set the optimal color rendering concentration according to the subdivided boundary line.

[0018] Further, in step S3, the printing density is divided into 8 levels, and level 6 is the best color density;

[0019] Upper boundary processing: set the upper boundary printing density to 6 and 1 alternately;

[0020] Lower boundary processing: set the lower boundary printing density to 4 and 2 alternately;

[0021] Left and right boundary line processing: From top to bottom, the boundary lines are set to 1 and 6 respectively.

[0022] The beneficial effect of adopting the above further solution is to set different printing densities according to different boundary lines, thereby improving the printing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a flowchart of a specific embodiment of the present invention;

[0024] Figure 2 Schematic diagram of the boundary line of the first embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the boundary line after processing according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0027] In the description of the present invention, it is necessary to understand that the terms "center", "length", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "inside", "outside", "peripheral", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred system or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0028] In the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] like Figure 1 As shown, a printing method for preventing white leakage at the junction of thermal transfer printing includes the following steps:

[0031] S1. Color separation: extract the color close to the color ribbon on the original. Specifically, in traditional printing, the various colors on the original are decomposed into four primary colors: cyan (C), magenta (M), yellow (Y), and black (K). However, thermal transfer printers only transfer the color on the color ribbon (ink) to the substrate, and cannot mix or overprint the pigments. The color separation of thermal transfer is to extract the color close to the color ribbon on the original.

[0032] S2. Boundary line identification: After the original is separated into colors, find the boundary lines between different color bands in the original image. Specifically, if the white point of the current color layer is located at the non-white point of other color layers, and there is at least one non-white point among the 8 points near the white point of the current color layer, then the white point is a boundary point, and multiple boundary points are connected to form a boundary line.

[0033] S3. Boundary growth: The printing density of the thermal transfer printer is divided into multiple levels, and the adjacent color blocks on each boundary line are staggered to set a high and a low density level. Further, the boundary line is divided into an upper boundary line, a lower boundary line, a left boundary line and a right boundary line, wherein the density of the upper boundary line of the color block is greater than or equal to the optimal color rendering density of the color block, the density of the lower boundary line of the color block is less than the optimal color rendering density of the color block, and the density of the left boundary line and the right boundary line of the color block is equal to the optimal color rendering density of the color block.

[0034] S4. If there is still white leakage at the thermal transfer printing location, repeat steps S1 to S3 until there is no white leakage at the boundary line of the thermal transfer printing location.

[0035] In the present invention, after the intersections between different color bands are determined through color separation, high and low concentration levels that are staggered with each other are set at the intersections, so that the intersections are staggered and printed, avoiding white leakage at the printing intersections, thereby improving the printing quality.

[0036] Embodiment 1

[0037] S1. Color separation: extract the color close to the color band on the original;

[0038] S2. Boundary line recognition: After the original is separated into different colors, find the boundary lines between different color bands in the original image. Figure 2 As shown, the white point of the current color layer is located at the non-white point of other color layers, and there is at least one non-white point among the 8 points near the white point of the current color layer, then the white point is a boundary point, the "0" area represents the distribution of non-white points of other layers, the middle area represents the distribution of non-white points of the current layer, the white point of the current layer is represented by "0", the non-white point of the current layer (printing area) is represented by "6", and the "1", "2" and part of the "0" outside the "6" are the boundary lines of the current layer.

[0039] S3. Boundary growth: The printing density of the thermal transfer printer is divided into multiple levels, and the adjacent color blocks on each boundary line are staggered to set a high and a low density level. Further, the boundary line is divided into an upper boundary line, a lower boundary line, a left boundary line and a right boundary line, wherein the density of the upper boundary line of the color block is greater than or equal to the optimal color rendering density of the color block, the density of the lower boundary line of the color block is less than the optimal color rendering density of the color block, and the density of the left boundary line and the right boundary line of the color block is equal to the optimal color rendering density of the color block.

[0040] Specifically, Figure 3 As shown, the printing density is divided into 8 levels, and level 6 is the best color rendering density;

[0041] Upper boundary processing: set the upper boundary printing density to 6 and 1 alternately;

[0042] Lower boundary processing: set the lower boundary printing density to 4 and 2 alternately;

[0043] Left and right boundary line processing: From top to bottom, the boundary lines are set to 1 and 6 respectively.

[0044] After the print density is set, the thermal transfer machine starts printing. If there is still leakage in the print after the above treatment, it is necessary to perform another round of border growth after the above treatment, that is, repeat S1 to S3 until there is no leakage.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A printing method for preventing white leakage at the junction of thermal transfer printing, characterized in that: The following steps are involved: S1. Color separation: extract the color close to the color band on the original; S2. Boundary line recognition: After the original is separated into different colors, find the boundary lines between different color bands in the original image; S3. Boundary growth: The printing density of the thermal transfer printer is divided into multiple levels, and the adjacent color blocks on each boundary line are alternately set with a high and a low density level; S4. If there is still white leakage at the thermal transfer printing, repeat steps S1 to S3 until there is no white leakage at the junction line of the thermal transfer printing; In step S2, if the white point of the current color layer is located at a non-white point of other color layers, and there is at least one non-white point among the eight points near the white point of the current color layer, then the white point is a boundary point, and multiple boundary points are connected to form a boundary line; In step S3, the boundary lines are divided into upper boundary lines, lower boundary lines, left boundary lines and right boundary lines, wherein the concentration of the upper boundary line of the color block is greater than or equal to the optimal color rendering concentration of the color block, the concentration of the lower boundary line of the color block is less than the optimal color rendering concentration of the color block, and the concentrations of the left boundary line and the right boundary line of the color block are equal to the optimal color rendering concentration of the color block.

2. The printing method for preventing white leakage at the junction of thermal transfer printing according to claim 1, characterized in that: In step S3, the printing density is divided into 8 levels, and level 6 is the best color density; Upper boundary processing: set the upper boundary printing density to 6 and 1 alternately; Lower boundary processing: set the lower boundary printing density to 4 and 2 alternately; Left and right boundary line processing: From top to bottom, the boundary lines are set to 1 and 6 respectively.

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