A composite embossing method, a composite printing roller set and a printed paper product

Abstract

The application discloses a composite embossing method, a composite printing roller set and a printed paper product, and belongs to the technical field of household paper production equipment. The composite embossing method comprises the following steps: jointly feeding first base paper and second base paper into a gap between a first pattern roller and a second pattern roller; performing pressing on the surface of the first base paper by a printing boss on the first pattern roller to form at least one printing pattern composed of a plurality of first indentations; and performing pressing on the surface of the second base paper in the region of the first indentation by a composite fine point on the second pattern roller to form a plurality of second indentations. Since the first indentation and the second indentation are actually obtained by pressing the partial region of the respective base paper, the overall thickness of the composite paper is not affected, so that the problems of appearance and thickness are well balanced. In addition, the first interlaced layer and the second interlaced layer are formed at the bottom of the first indentation, so that the composite of the base papers is more firm.

Description

Technical Field

[0001] This invention belongs to the technical field of household paper production equipment, and more specifically, relates to a composite embossing method, a composite printing roller assembly, and printed paper products. Background Technology

[0002] Paper towels are a necessity in people's daily lives, and they are usually made of two or more layers of paper. To enhance absorbency and appearance, many paper towels are embossed with printed patterns to meet market demand. Traditional embossed paper towels are generally bonded using sprayed glue, which often contains toxic or corrosive substances, thus posing a health risk. Furthermore, the glue hardens after solidification, affecting the feel of the paper towels.

[0003] To address the shortcomings of adhesive-coated lamination, some adhesive-free lamination paper products and equipment have emerged on the market. Their main working principle involves using mechanical pressure to compress multiple sheets of paper, causing the fibers to interweave and form an adhesive-free composite.

[0004] In some solutions, a "point-to-flat" glue-free lamination method is adopted, that is, the base paper is first pre-embossed to form a pattern; then, multiple sheets of base paper are extruded and laminated in the pattern area formed by the pre-pressing through several composite protrusions on the surface of a printing roller and the flattening roller of another light roller.

[0005] This "point-to-flat" composite method can achieve glue-free paper lamination, but when the two base papers are pressed together at the cutting point of the printing roller and the light roller, the pre-pressed pattern on the base paper near the light roller will be squeezed to a certain extent, resulting in an indistinct pattern and a poorer embossing effect.

[0006] In some solutions, a "point-to-point" glue-free lamination method is adopted, that is, the base paper is first pre-embossed to form a pattern; then, several composite protrusions on one printing roller and several composite protrusions on the surface of another printing roller are extruded and laminated in the pattern area formed by pre-pressing.

[0007] This composite method effectively avoids damage to the patterns formed by pre-pressing, ensuring the integrity of the patterns. However, this "point-to-point" composite method requires high precision in the relative positions of the composite protrusions on the two printing rollers, ensuring that the composite protrusions on the two rollers correspond one-to-one, which greatly increases the operational difficulty of actual production.

[0008] To address the aforementioned issues, existing technologies have developed a "fine-texture composite" technique. This involves first using several printing protrusions on a printing roller in conjunction with a rubber roller to form a pre-printed pattern on the base paper. Then, the printing protrusions on the printing roller cooperate with composite dots on another fine-texture roller to form multiple composite points within the area of ​​the pre-printed pattern. This effectively ensures the integrity of the printed pattern while reducing the positional requirements between the printing protrusions and the composite dots.

[0009] It is evident that existing technologies regarding adhesive-free lamination and embossing have been disclosed, but there is still room for improvement. For example, in current adhesive-free lamination and embossing technologies, each layer of base paper is pre-patterned before lamination (generally formed by the extrusion of printing protrusions on the adhesive roller and printing roller), and then lamination is performed at the recessed areas of the pattern, resulting in an air layer between adjacent lamination areas. While this air layer can improve the aesthetics of the laminated tissue paper, it also causes the laminated tissue paper to expand excessively, which is detrimental to saving packaging materials and transportation costs. Especially for small, portable paper products, the increased thickness of a single tissue paper within the same packaging space sacrifices the quantity of tissue paper, thus significantly reducing customer satisfaction. Summary of the Invention

[0010] 1. The problem to be solved

[0011] To address the issue that existing glue-free laminating devices cannot effectively balance aesthetics and thickness, this invention provides a composite embossing method, a composite printing roller assembly, and printed paper products. In this invention, the thickness of the base paper is utilized to thin it, forming an embossed texture with a specific shape; simultaneously, this does not increase its thickness, thus achieving a good balance between aesthetics and thickness.

[0012] 2. Technical Solution

[0013] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0014] A composite embossing method according to the present invention,

[0015] The roller assembly used has a first pattern roller and a second pattern roller. The roller surface of the first pattern roller is provided with several printing protrusions, and the roller surface of the second pattern roller is densely distributed with several composite fine dots at intervals.

[0016] During processing, the distance H between the top of the printing boss and the roller surface of the second printing roller is controlled to be less than the stacking thickness of the base paper that is jointly incorporated; the first base paper and the second base paper are jointly incorporated into the gap between the first printing roller and the second printing roller, and the first base paper and the second base paper are squeezed by the first printing roller and the second printing roller, thus completing the printing and lamination work at the same time.

[0017] The printing protrusions are pressed on the surface of the first base paper to form at least one printing pattern composed of several first indentations; the composite dots corresponding to the printing protrusions are pressed on the surface of the second base paper to form multiple second indentations, and a first interlacing layer is pressed to form in the area where the bottom of the first indentation overlaps with the second indentation.

[0018] In some embodiments, a second interlacing layer is formed in the area where the bottom of the first indentation does not overlap with the second indentation.

[0019] In some embodiments, the height of the composite dots is greater than the thickness of the second base paper, so that the second indentation formed by the composite dots can be more clearly presented on the first base paper.

[0020] In some embodiments, the height of the composite fine dots is 0.05-0.2 mm.

[0021] In some embodiments, the first base paper and / or the second base paper are pre-pressed with a plurality of third indentations; the plurality of third indentations form a printed pattern or recesses with a certain shape.

[0022] In some embodiments, the pressing depth of the third indentation is less than that of the first indentation. When the third indentation is located in the printing protrusion area, it can be further pressed and laminated onto the first indentation.

[0023] A composite printing roller assembly of the present invention includes a first printing roller and a second printing roller that abut against each other. The first printing roller has a plurality of printing protrusions formed on its surface, and the second printing roller has a plurality of composite fine dots densely distributed at intervals on its surface.

[0024] The distance H between the top of the printing boss and the roller surface of the second printing roller is 0.08-0.28mm, thereby forming a first pressing area between the printing boss and the composite fine dots. The first pressing area forms fine dots on the paper and fills the texture corresponding to the printing boss. A second pressing area is formed between the printing boss and the roller surface of the second printing roller.

[0025] In some embodiments, the height of the composite fine dots protruding from the surface of the second patterned roller is 0.10mm-0.25mm.

[0026] In some embodiments, the pressed area of ​​the composite fine dots is less than 0.1 mm. 2 Furthermore, the gap between adjacent composite fine points is 0.05-0.5mm.

[0027] In some embodiments, it also includes at least one set of pre-printing rollers consisting of a third printing roller and a rubber roller, wherein the third printing roller has a plurality of pre-printing protrusions distributed on it; wherein the pre-printing protrusions form a printing pattern with a certain shape, or a series of protrusions, or a combination of printing pattern and protrusions.

[0028] In some embodiments, the height of the pre-printed protrusion is less than the height of the printing protrusion.

[0029] In some embodiments, the height of the printing protrusion is 0.8-2.5 mm; the height of the pre-printed protrusion is 0.5-2.0 mm.

[0030] A composite printing roller assembly of the present invention includes a first printing roller and a second printing roller that abut against each other. The first printing roller has a plurality of printing protrusions on its surface, and the second printing roller has a plurality of composite fine dots densely distributed at intervals on its surface.

[0031] A first pressing area is formed between the printing protrusion and the composite fine dots, and the first pressing area forms fine dots on the paper and fills the texture corresponding to the printing protrusion; a second pressing area is formed between the printing protrusion and the roller surface of the second printing roller; and the height of the composite fine dots protruding from the roller surface of the second printing roller is 0.08-0.28mm.

[0032] A printed paper product of the present invention includes a first base paper and a second base paper laminated together. The first base paper and the second base paper, under mechanical pressing by the same set of rollers, respectively form a first indentation and a second indentation on their opposite surfaces; wherein...

[0033] The densely packed second indentations fill the area of ​​the first indentation, and a first interlacing layer is formed in the overlapping area of ​​the two indentations.

[0034] In some embodiments, a second interlacing layer is formed in the area where the bottom of the first indentation does not overlap with the second indentation.

[0035] In some embodiments, the first base paper and the second base paper are partially laminated within the first indentation area; the portions outside the first indentation area are mutually bonded; and the depth of the first indentation and the second indentation does not exceed the thickness of their respective base papers.

[0036] In some embodiments, a third imprint is formed on the first base paper and / or the second base paper, the area of ​​the third imprint being larger than the area of ​​the second indentation; the third imprint forms a printed pattern with a certain shape, or a series of indentations, or a combination of a printed pattern and indentations.

[0037] In some embodiments, the third imprint is a series of indentations that fill all areas of the original paper surface other than the first indentation, or there is a boundary between the indentations and the area where the first indentation forms the printed pattern.

[0038] 3. Beneficial effects

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] (1) A composite embossing method of the present invention utilizes the thickness of the base paper itself to press a first embossing on a first base paper and a second embossing on a second base paper, thereby simultaneously completing the composite operation between the two base papers. Since the first and second embossings are actually obtained by thinning a portion of their respective base papers, they do not affect the overall thickness of the composite paper, thus effectively balancing aesthetics and thickness. In addition, since a first interlacing layer and a second interlacing layer are formed at the bottom of the first embossing, the composite between the base papers is made more robust.

[0041] (2) The composite printing roller assembly of the present invention utilizes the cooperation of two printing rollers to simultaneously complete the printing and lamination operations between various base papers, obtaining printed paper products with printed patterns without pre-printing. This ensures the aesthetic appeal of the paper products without excessively increasing their thickness. Furthermore, by controlling the distance between the top of the printing boss and the roller surface of the second printing roller, the lamination area between the base papers can be greatly increased, ensuring the strong lamination between the base papers. At the same time, it eliminates the risk of excessive wear or even breakage of the lamination dots caused by the large pressing force required for printing.

[0042] (3) A printed paper product of the present invention can form a printed pattern of a certain shape on the surface of the first base paper by means of the first indentation, and the shape of the second indentation can be presented on the first base paper through the first indentation, which can effectively enrich the aesthetics of the paper product; at the same time, the first base paper and the second base paper are in a mutually layered state in the part of the first indentation area, which can effectively ensure the layering area; while the parts outside the first indentation area are in a mutually bonded state, avoiding the existence of air layer, which is conducive to ensuring the thickness of the paper after lamination. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of a composite printing roller assembly according to the present invention;

[0044] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle;

[0045] Figure 3 This is a schematic diagram showing the fit of the first and second patterned rollers after their surfaces have been unfolded in this invention.

[0046] Figure 4 This is another structural schematic diagram of a composite printing roller assembly according to the present invention;

[0047] Figure 5 This is a schematic diagram of the structure of a printed paper product according to the present invention;

[0048] Figure 6 for Figure 5 A magnified view of a portion of point A in the middle.

[0049] Figure 7 This figure illustrates one distribution pattern of the indentations on the printed paper product in this invention.

[0050] Figure 8 This figure shows another distribution of the indentations on the printed paper in this invention.

[0051] In the diagram: 100, first printing roller; 110, printing boss;

[0052] 200. Second flower roller; 210. Composite fine dots;

[0053] 300. Pre-pressed roller assembly;

[0054] 400. First sheet material; 410. First indentation;

[0055] 500. Second base paper; 510. Second indentation;

[0056] 610. First interlacing layer; 620. Second interlacing layer. Detailed Implementation

[0057] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings.

[0058] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0059] The existing "fine-texture composite" technology involves first using several printing protrusions on a printing roller in conjunction with a rubber roller to form a pre-printed pattern on the base paper. Then, the printing protrusions on the printing roller cooperate with composite dots on another fine-texture roller to form multiple composite dots within the area of ​​the pre-printed pattern. Due to the small size of the composite dots and the high pressure applied during pressing, fine-texture dots can be easily formed. Its advantages include convenient control, ensuring the integrity of the printed pattern, and reducing the positional requirements between the printing protrusions and the composite dots. However, the problem is that the resulting product is thicker, reducing the amount of paper that can be accommodated in the same volume.

[0060] Regarding the thickness issue, one possible optimization is to replace the smooth roller with a fine-textured roller, which works directly with the printing roller to reduce thickness. However, due to pressure issues, the fine texture would wear off quickly; if the pressure is too low, the pattern on the front side cannot be clearly displayed, making this solution unusable in actual production.

[0061] This invention provides a composite embossing method, a composite printing roller assembly, and printed paper products. Its main objective is to form a printed pattern on the surface of the printed paper products and fill it with fine dots to improve clarity. It should be noted that the printed pattern in this invention can be graphics, text, or a combination of both, depending on actual needs.

[0062] The present invention will be further described below with reference to specific embodiments.

[0063] In this embodiment, a composite embossing method allows for simultaneous printing and lamination of a first base paper 400 and a second base paper 500, which are stacked together, under the pressure of a first printing roller 100 and a second printing roller 200. The first printing roller 100 has several printing protrusions 110 on its surface, which can be combined to form at least one printed pattern. The second printing roller 200 has several densely distributed composite dots 210 on its surface, and the pressing area of ​​each printing protrusion 110 is more than twice that of the composite dots 210, allowing each printing protrusion 110 to be pressed and engaged with multiple composite dots 210. Simultaneously, the distance H between the top of the printing protrusion 110 and the surface of the second printing roller 200 is less than the combined thickness of the stacked base papers.

[0064] It is worth mentioning that the first base paper 400 and the second base paper 500 in this embodiment can be single-layer base paper or multi-layer base paper, and no specific limitation is made here.

[0065] The specific steps of the composite embossing method in this embodiment are as follows:

[0066] The first base paper 400 and the second base paper 500 are fed into the gap between the first pattern roller 100 and the second pattern roller 200. The printing protrusion 110 presses on the surface of the first base paper 400 to form at least one printed pattern composed of a plurality of first indentations 410.

[0067] Multiple second indentations 510 are formed by pressing the composite fine dots 210 on the surface of the second base paper 500 within the area of ​​the first indentation 410. Since the distance H between the printing protrusions 110 and the roller surface of the second printing roller 200 is less than the combined thickness of the base papers, a first interlacing layer 610 is formed between the first base paper 400 and the second base paper 500 within the area where the bottom of the first indentation 410 overlaps with the second indentation 510. In the area where the bottom of the first indentation 410 does not overlap with the second indentation 510, multiple layers of base paper are also compressed, thereby forming a second interlacing layer 620. The pressing force of the first interlacing layer 610 is greater than that of the second interlacing layer 620 to ensure the strong bonding between the first base paper 400 and the second base paper 500.

[0068] It should be noted that the distance H between the printing protrusion 110 and the roller surface of the second printing roller 200 can be adjusted according to the thickness (i.e., number of layers) of the base paper to be laminated. When using a single layer of base paper for lamination, the distance H can be appropriately reduced; while when using multiple layers of base paper for lamination, the thickness of each layer of base paper will also increase; at this time, the value of the distance H can be appropriately increased to form a deeper indentation, thereby making the printed pattern formed by the indentation clearer and more three-dimensional.

[0069] Specifically, in this embodiment, both the first base paper 400 and the second base paper 500 are double-layered base papers. Since the first base paper 400 and the second base paper 500 in this embodiment have not been pre-printed, the combined thickness of each base paper can be approximated as the sum of the thicknesses of each base paper. That is, the combined thickness of the four base papers in this embodiment is approximately 0.2-0.28 mm (each layer of facial tissue typically weighs 11-14 g and has a thickness of about 0.05-0.07 mm). Therefore, the distance H between the printing protrusion 110 and the roller surface of the second printing roller 200 can be controlled within the range of 0.08-0.28 mm, for example, 0.09 mm, 0.14 mm, 0.20 mm, 0.26 mm, etc. This distance control ensures the clarity of the indentation and the pressure during lamination, while also preventing the base paper from being crushed.

[0070] In some embodiments, the height of the composite dots 210 should be greater than the thickness of the second base paper 500. At the same time, without compromising the second base paper 500, the height of the composite dots 210 should be as large as possible so that the second indentation 510 formed by the composite dots 210 can be more clearly presented on the first base paper 400, thereby further ensuring the clarity of the printed pattern.

[0071] However, considering that printing and lamination are performed simultaneously in this embodiment, in order to create indentations on the original thickness of the base paper, the pressing pressure between the two printing rollers needs to be greater than the pressure applied during traditional pre-pressing of the pattern before lamination. In this case, if the height of the lamination dots 210 is too large, it will cause excessive wear or even breakage. Therefore, in this embodiment, the height of the lamination dots 210 is controlled within 0.05-0.2 mm, for example, 0.06 mm, 0.13 mm, 0.18 mm, etc. This ensures the clarity of the indentations and extends the service life of the lamination dots 210.

[0072] In addition, in cases where packaging thickness is not strictly required, such as kitchen paper and bathroom paper, before the first base paper 400 and the second base paper 500 are joined into the two printing rollers for printing lamination, the first base paper 400 can be pre-pressed with several third creases to further enrich the appearance of the printed paper and improve its absorbency. Of course, the second base paper 500 can also be pre-pressed with several third creases.

[0073] The following section provides a detailed explanation of the third indentation, using the example of the first base paper 400 having a third indentation. The aforementioned third indentation can form a printed pattern with a specific shape, or it can form a series of indentations on the paper surface, or a combination of both. It is important to note that when the third indentation is used to form a printed pattern, it must be staggered from the first indentation 410 to prevent the pre-formed third indentation from being destroyed when pressing the first indentation 410.

[0074] In some embodiments, in order to minimize the impact on the overall thickness of the printed paper, the pressing depth of the third indentation may be less than the pressing depth of the first indentation 410.

[0075] The composite embossing method of this embodiment essentially utilizes the thickness of the original paper itself to press a first indentation 410 on the first original paper 400 and a second indentation 510 on the second original paper 500, thereby simultaneously completing the composite operation between the two original papers. Since the first indentation 410 and the second indentation 510 are actually obtained by pressing a portion of their respective original paper to thin them, they do not affect the overall thickness of the composite paper, thus effectively balancing aesthetics and thickness. At the same time, it also gives the printed pattern high clarity.

[0076] To implement the above-described composite embossing method, this embodiment provides a composite printing roller assembly.

[0077] like Figure 1 , Figure 2As shown, this embodiment of a composite printing roller assembly includes a first printing roller 100 and a second printing roller 200 that abut against each other and rotate in opposite directions. The first printing roller 100 has a plurality of printing protrusions 110 formed on its surface, each protrusion forming at least one printed pattern of a certain shape. The second printing roller 200 has a plurality of composite fine dots 210 densely distributed at intervals on its surface. Simultaneously, at the composite position, the composite fine dots 210 cooperate with the printing protrusions 110 to press and print onto the first base paper 400 and the second base paper 500 that are jointly incorporated, and a series of fine dots are filled within the texture formed by the printing protrusions 110. Here, "composite position" refers to the point where, as the printing protrusions 110 and the composite fine dots 210 rotate to a certain point, the gap between them is smallest, and the first base paper 400 and the second base paper 500 are jointly incorporated at this point for pressing and composite. This point is the composite position. It should also be noted that the distance H between the pressing surface of the printing boss 110 and the roller surface of the second printing roller 200, and the distance h between the pressing surface of the printing boss 110 and the pressing surface of the composite fine dot 210 mentioned below, are all relative to the composite position.

[0078] In some embodiments, the printing protrusions 110 described above can be in the form of raised dots or raised lines; raised lines can be straight lines, curves, or a combination thereof. Meanwhile, raised lines can be segmented, or can extend along the entire axial direction of the first printing roller 100, or a combination of both. Their specific formation and size depend on the desired printing pattern and are not specifically limited herein.

[0079] In some embodiments, the composite fine dots 210 described above can be raised dots or raised lines, but their pressing surface is smaller than that of the printing raised platform 110. The specific pressing area of ​​the composite fine dots 210 can be determined according to actual production needs. Generally, the pressing surface area of ​​the composite fine dots 210 does not exceed 0.2 mm. 2 Furthermore, when the composite fine dot 210 is convex, the length and width of its pressing surface do not exceed 0.6 mm. It is worth noting that the pressing surface here refers to the end faces of the printing protrusion 110 and the composite fine dot 210 that approach each other when they are pressed together at the composite position; it can also be understood as their respective tops. Simultaneously, the composite fine dots 210 do not need to form a printed pattern with a specific shape, but rather are merely used to re-outline and press together within the area of ​​the printed pattern formed by the printing protrusion 110. In other words, the composite fine dots 210 do not form a completely new printed pattern, but simply outline along the interior of the printed pattern formed by the printing protrusion 110, so that the printed pattern formed by the printing protrusion 110 can be presented more clearly on both sides of the composite paper.

[0080] Specifically, such as Figure 3 , Figure 5 As shown (for ease of display), Figure 3 (The roller surfaces of the two pattern rollers are unfolded). In this embodiment, at the composite position, the distance h between the pressing surface of the printing protrusion 110 and the pressing surface of the composite fine point 210 is less than the overlap thickness D of the first base paper 400 and the second base paper 500, thereby forming a first pressing area between the printing protrusion 110 and the composite fine point 210. When the first base paper 400 and the second base paper 500 do not have patterns pre-formed, the overlap thickness D is the sum of the thicknesses of each base paper itself.

[0081] When the first base paper 400 and the second base paper 500 are joined together in the first pressing area, the printing protrusion 110 presses a first indentation 410 on the first base paper 400, which is concave from the outside to the inside. The composite fine dot 210 presses a second indentation 510 on the second base paper 500, which is concave from the outside to the inside, and a first interlacing layer 610 is formed at the junction of the second indentation 510 and the first indentation 410. Within the area of ​​the first interlacing layer 610, the fibers of the first base paper 400 and the second base paper 500 are interlaced, thus presenting a layered state, bonding the two base papers together.

[0082] In this embodiment, the first indentation 410 and the second indentation 510 are actually formed by thinning the portion of their respective base paper located at the composite position. Therefore, the first indentation 410, while forming a pattern, does not protrude from the inner surface of the first base paper 400. Thus, it does not increase the thickness of the first base paper 400. Meanwhile, since the second indentation 510 is formed within the area covered by the first indentation 410, although it does not form a completely new pattern, when the base paper is relatively thin, the shape of the second indentation 510 itself will be visible through the first indentation 410 onto the first base paper 400. This makes the pattern formed by the first indentation 410 finer, clearer, and more three-dimensional, greatly enhancing the aesthetics of the composite paper.

[0083] In some embodiments, at the composite location, the distance H between the pressing surface of the printing protrusion 110 and the roller surface of the second printing roller 200 (i.e., the recessed area between adjacent printing protrusions 110) is also smaller than the stacking thickness D of the first base paper 400 and the second base paper 500, thereby forming a second pressing area between the printing protrusion 110 and the roller surface of the second printing roller 200. When the first base paper 400 and the second base paper 500 are both incorporated into the second pressing area, the incorporated base papers can also be extruded and laminated to form a second interlacing layer 620. Although the pressing strength of the second interlacing layer 620 is less than that of the first interlacing layer 610, it can still achieve the composite effect.

[0084] Similarly, the second interlacing layer 620 mentioned above is formed by compressing two base papers, thus not increasing the thickness of the base papers. In other words, the laminated paper is in a layered state throughout the bottom of the entire first indentation 410, greatly increasing the layering area between the base papers and effectively improving the bonding strength. At the same time, the parts of the laminated paper outside the first indentation 410 area are in a mutually adhered state, so its overall thickness is approximately the same as the thickness of the original laminate.

[0085] In some embodiments, at the composite position, the distance H between the pressing surface of the printing boss 110 and the roller surface of the second printing roller 200 is 0.08-0.28 mm. This is because the thickness of a single layer of base paper is generally about 0.05-0.07 mm, while when both the first base paper 400 and the second base paper 500 are single sheets of base paper, their stacking thickness D is about 0.10-0.14 mm. At this time, the H value is taken as the minimum value of 0.08 mm, which is not only less than the stacking thickness of 0.10 mm, but also ensures that the base paper is subjected to sufficient extrusion pressure in the second pressing area to form the second interlacing layer 620. Since the composite fine point 210 protrudes from the roller surface of the second printing roller 200, the distance between the composite fine point 210 and the printing boss 110 is less than H, thereby allowing the incoming base paper to be subjected to greater extrusion pressure in the first pressing area to form a first interlacing layer 610 with better pressing effect. Of course, the specific value of H can be adjusted according to the actual stacking thickness of the first base paper 400 and the second base paper 500.

[0086] In some embodiments, in order to ensure that the second indentation 510 on the second base paper 500 can be more clearly presented on the first base paper 400, the height of the composite fine dots 210 should be as large as possible without the second base paper 500 being crushed, so that the second indentation 510 formed by the composite fine dots 210 can be more clearly presented on the first base paper 400, thereby further enhancing the aesthetics of the printed paper.

[0087] However, considering that printing and lamination are performed simultaneously in this embodiment, in order to press indentations onto the original thickness of the base paper, the pressing between the two printing rollers requires greater pressure compared to traditional pre-pressing of patterns. In this case, if the lamination dots 210 are made at a larger height, it will cause excessive wear or even breakage of the lamination dots 210.

[0088] Therefore, in this embodiment, based on the distance H between the pressing surface of the printing protrusion 110 and the roller surface of the second printing roller 200 being 0.08-0.28mm, the height of the composite fine dots 210 is controlled within the range of 0.06mm-0.25mm, preferably 0.10mm-0.20mm. For example, 0.13mm, 0.17mm, 0.19mm, etc. This ensures the clarity of the indentation and extends the service life of the composite fine dots 210. Specifically, in this embodiment, both the first base paper 400 and the second base paper 500 are two-layer base papers, and the height of the composite fine dots 210 protruding from the roller surface of the second printing roller 200 is preferably around 0.15mm, for example, 0.14mm, 0.15mm, 0.16mm, etc. In other words, this embodiment does not excessively require a high degree of clarity for the second indentation 510 on the first base paper 400. However, when using 2-8 sheets of base paper for lamination, the second indentation 510 can also be produced on the first base paper 400.

[0089] In some embodiments, in order to reduce the frictional wear of the composite dots 210, the first pattern roller 100 and the second pattern roller 200 adopt different diameters, so that the composite dots 210 at different positions alternately squeeze and cooperate with the printing boss 110, thereby effectively extending the service life of the composite dots 210.

[0090] Meanwhile, the hardness of the printing protrusions 110 and the composite fine dots 210 is 50-70 HRC. This hardness is chosen to ensure that the printing protrusions 110 and the composite fine dots 210 have sufficient strength to meet the requirements of pressing and laminating; on the other hand, it prevents the printing protrusions 110 and the composite fine dots 210 from cracking easily due to excessive hardness.

[0091] Furthermore, since the composite dots 210 alternately engage with the printing protrusions 110 through compression, to ensure the synchronicity of wear between the composite dots 210 and the printing protrusions 110, the hardness of the printing protrusions 110 can be slightly greater than that of the composite dots 210. Preferably, the hardness of the printing protrusions 110 is controlled within the range of 55-65 HRC, and the hardness of the composite dots 210 is controlled within the range of 50-60 HRC.

[0092] In some embodiments, since the frictional loss of the composite fine dots 210 is effectively controlled, the composite fine dots 210 can be made smaller, and their pressing area can be less than 0.1 mm. 2 For example, 0.02mm 2 0.05mm 2 0.07mm 2 0.09mm 2Smaller composite dots 210 can be more densely outlined within the printing pattern area formed by the printing protrusions 110, which is equivalent to filling the printing pattern area with more dots, or forming more "pixels," thereby effectively improving the resolution of the printing pattern and making it look more realistic and clear. However, if the dots are too densely packed, visual fatigue may occur during observation, making the printing pattern appear less clear. In addition, if the dots are too densely packed, i.e., the spacing between adjacent composite dots 210 is too small, it will be detrimental to the formation of the second interlacing layer 620. Especially for some kitchen and bathroom paper with coarser fibers, if the spacing between adjacent composite dots 210 is too small, it is difficult for the base paper to be squeezed into the spacing, which will affect the formation of the second interlacing layer 620. Therefore, in this embodiment, the gap between adjacent composite dots 210 is controlled within the range of 0.05-0.5mm, for example, 0.08mm, 0.14mm, 0.22mm, 0.35mm, 0.45mm, etc. The preferred size is 0.15mm-0.3mm, for example, 0.18mm, 0.25mm, etc. In this embodiment, by reasonably controlling the size and spacing of the composite fine dots 210, the clarity of the printed pattern can be guaranteed without affecting the formation of the second interlacing layer 620, so as to ensure the firmness of the composite between the base papers.

[0093] Preferably, the composite fine dots 210 have a columnar structure, and the pressing surface of the composite fine dots 210 is a square structure. The length and width of this square pressing surface are both 0.1-0.3 mm, for example, 0.12 mm, 0.18 mm, 0.26 mm, etc. Meanwhile, the spacing between adjacent composite fine dots 210 is controlled within the range of 0.08-0.25 mm, for example, 0.12 mm, 0.18 mm, 0.23 mm, etc. Compared with traditional spherical pressing surfaces, because the square pressing surface is a plane, the pressing force on the base paper is more uniform throughout the pressing area, thus helping to ensure the composite effect.

[0094] Specifically, in this embodiment, the height of the composite fine dots 210 is 0.2 mm, and the spacing between adjacent composite fine dots 210 is 0.15 mm. The overall pressing surface of the composite fine dots 210 is a 0.2 mm * 0.2 mm square structure. Meanwhile, to prevent the corners of the square pressing surface from easily scratching the base paper, rounded corners are made at the corners of the square pressing surface.

[0095] refer to Figure 4As shown, another embodiment of a composite printing roller group in this example includes a pre-embossing roller group 300 and a composite roller group composed of the first printing roller 100 and the second printing roller 200. The pre-embossing roller group 300 may be provided in one set for pre-pressing the first base paper 400 or the second base paper 500. Alternatively, two sets of pre-embossing roller groups 300 may be provided, each pre-pressing the first base paper 400 and the second base paper 500 respectively to form a third indentation on their respective base papers.

[0096] Specifically, the pre-printing roller assembly 300 includes a third printing roller and a rubber roller that abut against each other, and a plurality of pre-printed raised areas are formed on the roller surface of the third printing roller. These pre-printed raised areas can be arranged according to a certain pattern shape to enrich the pattern shape of the composite paper and enhance its aesthetic appeal. At this time, in order to prevent the pattern pre-pressed by the pre-printed raised areas from being destroyed by re-pressing during the later lamination process, the pattern formed by the pre-printed raised areas on the base paper should be staggered from the pattern formed by the printing raised areas 110.

[0097] Of course, the aforementioned pre-printed raised areas may not form a specific pattern. That is, the pre-printed raised areas are not intended to create a patterned design on the base paper, but rather to form a series of "dimples" to increase the feel and absorbency of the composite paper. In this case, there is no need to consider the misalignment between the "dimples" and the pattern formed by the printing protrusions 110. It is only necessary to ensure that the height of the printing protrusions 110 is greater than the height of the pre-printed raised areas, so that the pre-formed "dimples" on the base paper are destroyed during the composite pressing process of the printing rollers, and new indentations can be formed. However, regardless of the structural form of the pre-printed raised areas, the interaction between the third printing roller and the rubber roller will inevitably increase the thickness of the base paper. Therefore, it is suitable for the production of some printed paper products where thickness is not a strict requirement.

[0098] In some embodiments, to keep the paper thickness within an acceptable range, the height of the pre-printed protrusions should be less than the height of the printing protrusions 110. The height of the pre-printed protrusions is preferably 0.5-2.0 mm, such as 0.6 mm, 1.3 mm, or 1.7 mm. The height of the printing protrusions 110 is 0.8-2.5 mm to meet the requirements of some kitchen paper towels and hand towels that require deeper embossing. For example, 1.1 mm, 1.6 mm, or 2.3 mm.

[0099] This embodiment of a composite printing roller assembly utilizes the cooperation of two printing rollers to simultaneously complete the printing and lamination operations between various base papers. Printed paper products with printed patterns can be obtained without pre-printing, ensuring the aesthetic appeal of the paper products without excessively increasing their thickness. Furthermore, by controlling the distance between the top of the printing protrusion 110 and the roller surface of the second printing roller 200, the height of the composite fine dots 210 protruding from the roller surface of the second printing roller 200 does not exceed 0.2mm. This significantly increases the lamination area between the base papers, ensuring the strong bonding between them. Simultaneously, it eliminates the risk of excessive wear or even breakage of the composite fine dots 210 caused by the large pressing force required for printing.

[0100] refer to Figure 5 , Figure 6 As shown, this embodiment also provides a printed paper product, including a first base paper 400 and a second base paper 500 laminated together. Under mechanical pressing by the same roller group, the first base paper 400 and the second base paper 500 respectively form a plurality of first indentations 410 and a plurality of second indentations 510 on their opposite surfaces. Each of the plurality of first indentations 410 can form at least one printed pattern, and each first indentation 410 is filled with a plurality of densely distributed second indentations 510. Simultaneously, a first interlacing layer 610 is formed at the junction of the first indentations 410 and the second indentations 510, thereby connecting the first base paper 400 and the second base paper 500 together.

[0101] For ease of description below, the surfaces of the first base paper 400 and the second base paper 500 that are close to each other are defined as the inner surfaces of their respective base papers, and the surfaces that are far apart from each other are defined as the outer surfaces of their respective base papers.

[0102] like Figure 5 As shown, when observing the printed paper product from the outer surface of the first base paper 400, in addition to seeing the pattern formed by the first embossing 410, one can also see the densely packed second embossings 510 through the first embossing 410. Furthermore, since the second embossings 510 are distributed at the bottom of the first embossing 410, and the area of ​​the second embossings 510 is much smaller than that of the first embossing 410, when observing the printed paper product from the outer surface of the first base paper 400, several small dots can be seen at the bottom of the first embossing 410, making the first embossing 410 clearer and also giving it a stronger three-dimensional effect. Similarly, when observing the printed paper product from the outer surface of the second base paper 500, one can also see the pattern formed by the densely packed second embossings 510, which is actually obtained by the second embossings 510 outlining the bottom of the first embossing 410.

[0103] Furthermore, a second interlacing layer 620 is formed between the first base paper 400 and the second base paper 500 in the area outside the first indentation 410 and the area outside the second indentation 510. That is, the portions of the second base paper 500 and the first base paper 400 within the area of ​​the first indentation 410 are mutually laminated, thus making the composite more robust. Simultaneously, when the first base paper 400 and the second base paper 500 are not pre-pressed, the portions of the printed paper outside the area of ​​the first indentation 410 are all mutually adhered. In other words, the thickness of the printed paper at this time is essentially the same as the thickness when the first base paper 400 and the second base paper 500 are stacked together.

[0104] To further enhance the aesthetic appeal of printed paper products, the first base paper 400 and the second base paper 500 can undergo pre-pressing treatment. That is, before the first base paper 400 and the second base paper 500 are jointly extruded and laminated, a third indentation can be pre-formed on the first base paper 400. This third indentation can form a pattern with a certain shape; or it can not form a pattern with a certain shape, but simply present a series of "dimples" on the base paper; or it can be a combination of "dimples" and patterns, that is, some of the third indentations form patterns, and some of the third indentations form dense "dimples".

[0105] Of course, to ensure the integrity of the pattern, the pattern formed by the pre-printed paper needs to be staggered from the pattern formed by the first crease 410. At the same time, in order to minimize the impact on the overall thickness of the printed paper, the pressing depth of the third crease can be less than the pressing depth of the first crease 410.

[0106] refer to Figure 7 As shown, in some embodiments, the third indentation is a series of dimples that fill all areas of the original paper surface other than the first indentation 410.

[0107] refer to Figure 8 As shown, in some embodiments, the third impression is a series of indentations, and these indentations do not fill the entire area of ​​the base paper surface other than the first indentation 410, but rather leave a boundary between the indentation and the area where the printed pattern is formed by the first indentation 410, so that the printed pattern is more prominent and has a stronger three-dimensional effect. Of course, the third indentation can also be pre-formed on the second base paper 500.

[0108] In this embodiment, a printed paper product can form a printed pattern of a certain shape on the surface of a first base paper 400 through a first indentation 410, and the shape of the second indentation 510 can be presented on the first base paper 400 through the first indentation 410, which can effectively enrich the aesthetics of the paper product and improve the clarity of the printed pattern. At the same time, the first base paper 400 and the second base paper 500 are in a mutually laminated state in the part within the first indentation area 410, which can effectively ensure the lamination area; while the parts outside the first indentation area 410 are in a mutually bonded state, avoiding the existence of air layers, which is conducive to ensuring the thickness of the laminated paper.

[0109] Additionally, it should be noted that although the presence of the first interlacing layer 610 and the second interlacing layer 620 is clearly visible in the accompanying drawings, these drawings are merely for illustrative purposes and do not imply that the first interlacing layer 610 and the second interlacing layer 620 will necessarily be detected. It is understood that the presence of the first interlacing layer 610 and the second interlacing layer 620 is for laminating the base paper. Therefore, when separating the base papers of the laminated printed paper product, if the base papers are felt to be adhered to each other in the corresponding areas, this can be considered as the presence of the first interlacing layer 610 and the second interlacing layer 620.

[0110] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A composite embossing method, characterized in that: The roller assembly used has a first pattern roller (100) and a second pattern roller (200). The roller surface of the first pattern roller (100) is provided with a number of printing protrusions (110), and the roller surface of the second pattern roller (200) is densely distributed with a number of composite fine dots (210). During processing, the distance H between the top of the printing boss (110) and the roller surface of the second printing roller (200) is controlled to be less than the stacking thickness of the base paper that is jointly incorporated; the first base paper (400) and the second base paper (500) are jointly incorporated into the gap between the first printing roller (100) and the second printing roller (200), and the first base paper (400) and the second base paper (500) are squeezed by the first printing roller (100) and the second printing roller (200) to complete the printing and lamination work at the same time; The printing protrusion (110) is pressed on the surface of the first base paper (400) to form at least one printing pattern composed of a plurality of first indentations (410); the composite fine dots (210) corresponding to the printing protrusion (110) are pressed on the surface of the second base paper (500) to form a plurality of second indentations (510); and a first interlacing layer (610) is pressed in the area where the bottom of the first indentation (410) overlaps with the second indentation (510).

2. The composite embossing method according to claim 1, characterized in that: In the area where the bottom of the first indentation (410) does not overlap with the second indentation (510), a second interlaced layer (620) is formed by pressing.

3. The composite embossing method according to claim 2, characterized in that: The height of the composite fine dots (210) is greater than the thickness of the second base paper (500), so that the second indentation (510) formed by the composite fine dots (210) can be more clearly presented on the first base paper (400).

4. The composite embossing method according to claim 1, characterized in that: The height of the composite fine dots (210) is 0.05-0.2 mm.

5. A composite embossing method according to any one of claims 1-4, characterized in that: The first base paper (400) and / or the second base paper (500) are pre-pressed with a number of third indentations; the number of third indentations form a printed pattern or indentation with a certain shape.

6. The composite embossing method according to claim 5, characterized in that: The pressing depth of the third indentation is less than that of the first indentation (410). When the third indentation is in the area of ​​the printing protrusion (110), it can be further pressed and composited on the first indentation (410).

7. A composite printing roller assembly, comprising a first printing roller (100) and a second printing roller (200) abutting each other, wherein a plurality of printing protrusions (110) are formed on the roller surface of the first printing roller (100), characterized in that: The second flower roller (200) has a number of densely distributed composite fine dots (210) on its roller surface; among them, The distance H between the top of the printing boss (110) and the roller surface of the second printing roller (200) is 0.08-0.28 mm, thereby forming a first pressing area between the printing boss (110) and the composite fine dots (210). The first pressing area forms fine dots on the paper and fills the texture corresponding to the printing boss (110). A second pressing area is formed between the printing boss (110) and the roller surface of the second printing roller (200).

8. A composite printing roller assembly according to claim 7, characterized in that: The height of the composite fine dots (210) protruding from the surface of the second pattern roller (200) is 0.10mm-0.25mm; the pressing area of ​​the composite fine dots (210) is less than 0.1mm. 2 The gap between adjacent composite fine points (210) is 0.05-0.5mm.

9. A composite printing roller assembly according to claim 7 or 8, characterized in that: It also includes at least one set of pre-printing roller group (300) consisting of a third printing roller and a rubber roller, wherein a number of pre-printing protrusions are distributed on the third printing roller; wherein the pre-printing protrusions form a printing pattern with a certain shape, or a series of protrusions, or a combination of printing pattern and protrusions.

10. A composite printing roller assembly according to claim 9, characterized in that: The height of the pre-printed protrusion is less than the height of the printing protrusion (110).

11. A composite printing roller assembly according to claim 10, characterized in that: The height of the printing protrusion (110) is 0.8-2.5mm; the height of the pre-printed protrusion is 0.5-2.0mm.

12. A composite printing roller assembly, comprising a first printing roller (100) and a second printing roller (200) abutting each other, wherein the roller surface of the first printing roller (100) is provided with a plurality of printing protrusions (110), characterized in that: The second flower roller (200) has a number of densely distributed composite fine dots (210) on its roller surface; among them, A first pressing area is formed between the printing protrusion (110) and the composite fine dots (210), the first pressing area forming fine dots on the paper and filling the texture corresponding to the printing protrusion (110); a second pressing area is formed between the printing protrusion (110) and the roller surface of the second printing roller (200); and the height of the composite fine dots (210) protruding from the roller surface of the second printing roller (200) is 0.08-0.28mm.

13. A printed paper product, comprising a first base paper (400) and a second base paper (500) laminated together, characterized in that: The first base paper (400) and the second base paper (500) have a first indentation (410) and a second indentation (510) respectively formed on their opposite surfaces under the mechanical pressing of the same roller group; wherein, The densely packed second indentations (510) fill the area of ​​the first indentation (410), and a first interlacing layer (610) is formed in the overlapping area of ​​the two indentations. The first indentation (410) and the second indentation (510) are formed by pressing the corresponding base paper thin.

14. A printed paper product according to claim 13, characterized in that: A second interlacing layer (620) is formed in the area where the bottom of the first indentation (410) does not overlap with the second indentation (510).

15. A printed paper product according to claim 13, characterized in that: The first base paper (400) and the second base paper (500) are partially laminated within the area of ​​the first indentation (410); the portions outside the area of ​​the first indentation (410) are partially bonded together; and the depths of the first indentation (410) and the second indentation (510) do not exceed the thickness of their respective base papers.

16. A printed paper product according to claim 13, characterized in that: A third imprint is formed on the first base paper (400) and / or the second base paper (500), the area of ​​the third imprint being larger than the area of ​​the second indentation (510); the third imprint forms a printed pattern with a certain shape, or a series of indentations, or a combination of a printed pattern and indentations.

17. A printed paper product according to claim 16, characterized in that: The third imprint is a series of indentations, and the indentations fill the entire area of ​​the original paper surface that is not the first indentation (410), or, there is a boundary between the indentations and the area where the first indentation (410) forms the printed pattern.

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