A combined printing device and method for rotary screen printing and digital printing

Abstract

The present invention discloses a combined printing device of rotary screen printing and digital printing, belonging to the technical field of intelligent printing. It includes a rotary screen printing mechanism at the front end and a digital printing mechanism arranged at the rear end of the rotary screen printing mechanism. The rotary screen printing mechanism is used to present a dark background pattern on the fabric, and the digital printing mechanism is used to present a multi-color pattern on the fabric. A printing alignment mechanism is arranged at the front end of the digital printing mechanism. The printing alignment mechanism includes a camera and a controller. The camera is used to photograph a specified basic pattern on the fabric after rotary screen printing. The processor receives the pattern collected by the camera, and after processing, compares it with the pattern to be processed by the digital printing mechanism. When the two patterns are not aligned, the processor controls the fabric direct injection conveying mechanism to perform corresponding fine-tuning operations on the fabric at the digital printing mechanism.

Description

Technical Field

[0001] The present invention relates to the field of intelligent printing technology, and in particular to a printing device and method combining rotary screen printing and digital printing. Background Art

[0002] Digital direct-injection printing involves digitizing various graphics, inputting them into a computer, processing them through a computerized color separation printing system, and then using specialized software and a printing system to directly print specialized dyes onto sizing semi-finished textiles or other media. This process then undergoes further processing to create the desired printed product. Compared to traditional printing, digital direct-injection printing produces clearer patterns and richer color depth, enabling personalized customization. It eliminates steps like tracing, film production, screen making, and engraving, significantly shortening the process, improving printing efficiency, and reducing production costs, in line with national environmental protection and energy conservation initiatives.

[0003] Existing digital printing usually uses electrostatic printheads to spray different pigments. When processing large background dark patterns, the printheads need to perform a large amount of inkjet operation. In this case, the workload of the printhead group of a specific color is extremely heavy, and a large amount of ink is prone to seeping on the fabric, which can easily cause the color of the finished fabric to be not fine enough. Summary of the Invention

[0004] The object of the present invention is to provide a printing device and method combining rotary screen printing and digital printing. By combining rotary screen printing and digital printing, dark background colors are processed by rotary screen printing, and complex and gorgeous multi-color colors are processed by digital printing, thereby improving the vividness and accuracy of the color of the finished fabric.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] A printing device combining rotary screen printing and digital printing, comprising a rotary screen printing mechanism at the front end and a digital printing mechanism arranged at the rear end of the rotary screen printing mechanism, wherein the rotary screen printing mechanism is used to present a dark background pattern on the fabric, and the digital printing mechanism is used to present a multi-color pattern on the fabric;

[0007] A first drying oven and a rotary conveying mechanism are arranged between the rotary screen printing mechanism and the digital printing mechanism, a fabric direct injection conveying mechanism is arranged at the front and rear ends of the digital printing mechanism, and a printing alignment mechanism is arranged at the front end of the digital printing mechanism;

[0008] The printing alignment mechanism includes a camera and a controller. The camera is used to capture a specified basic pattern on the fabric after rotary screen printing. The processor receives the pattern collected by the camera, processes it, and then compares it with the pattern to be processed by the digital printing mechanism. When the two patterns are not aligned, the processor controls the fabric direct injection conveying mechanism to perform corresponding fine-tuning operations on the fabric at the digital printing mechanism.

[0009] Further, the digital printing mechanism includes a printing host and a nozzle component. A smooth platen is arranged below the nozzle component. The fabric to be printed is arranged between the nozzle component and the platen. The fabric direct injection conveying mechanism is arranged at the front and rear ends of the platen to enable the fabric to be printed to be conveyed smoothly between the two.

[0010] Further, the camera is arranged at the front end of the nozzle component, and the distance between the center point of the camera and the nozzle component is the same as the distance between single-pattern cycles of the rotary screen printing.

[0011] Further, the rotary conveying mechanism includes an adjustment roller shaft that can move up and down freely. Both ends of the adjustment roller shaft are connected to a straight rod through bearings and sliders.

[0012] A printing method combining rotary screen printing and digital printing includes:

[0013] Perform color separation on the original printed pattern with a cyclic structure, select the background pattern, generate a monochromatic first pattern, make a rotary screen based on the first pattern, and mix the corresponding pigments for the color of the first pattern, and place the pigments inside the rotary screen of the rotary screen printing mechanism.

[0014] After removing the first pattern part from the original pattern, generate a second pattern, perform YMCK color separation on the second pattern to produce a group of YMCK patterns, and configure the group of YMCK patterns to the nozzles for corresponding direct injection operations.

[0015] Further, in the operations of generating the first pattern and the second pattern, retain a certain overlapping contour between them, and perform a color reduction process on the color within the contour in the first pattern.

[0016] Further, during the color reduction process, it is implemented in a progressive manner of increasing color reduction from the inside to the edge.

[0017] An alignment method for printing combining rotary screen printing and digital printing includes:

[0018] Select an area with features in the first pattern to generate a basic pattern. The basic pattern with distinguishable features appears only once on a straight line in a single pattern cycle, and it includes at least two basic feature points on the straight line at the front and back. Measure the actual distance value between the two basic feature points.

[0019] The center point of the camera is arranged at the front end of the nozzle component, and the distance between the two is made consistent with the distance between individual fabric cycles in rotary screen printing. The center point of the camera is arranged directly above the midpoint of the basic feature points.

[0020] When the basic pattern part of the fabric is conveyed to the center point of the camera, the camera captures the basic pattern area of the fabric to generate a captured pattern. The processor of the printing host obtains the captured pattern and compares it with the basic pattern in a center-aligned manner. During the comparison operation, edge detection can be performed on the basic pattern and the captured pattern to obtain corresponding patterns that only include the image edge lines, and based on the actual distance value, the deviation value between the captured pattern and the basic pattern is calculated.

[0021] When the deviation value is less than or equal to the preset minimum deviation value, the original digital printing operation can continue to be maintained.

[0022] When the deviation value is greater than the preset minimum deviation value, the processor controls the fabric direct injection conveying mechanism, and during the interval when the nozzle reciprocates, the fabric is finely adjusted forward or backward to align the captured pattern with the basic pattern.

[0023] Further, when the deviation value is greater than the preset maximum deviation value, the printing host controls the fabric direct injection conveying mechanism, and during the interval when the nozzle reciprocates, the fabric is adjusted forward or backward and adjusted according to the deviation value.

[0024] Further, when the deviation value is less than or equal to the set maximum deviation value, the printing host divides the deviation value by the number of nozzle reciprocations in a single pattern cycle to obtain a single adjustment value. The printing host controls the fabric direct injection conveying mechanism, and during each interval when the nozzle reciprocates, the fabric is finely adjusted forward or backward with the single adjustment value.

[0025] Adopting this solution, compared with the prior art, it has the following advantages:

[0026] This solution is a combined printing device for rotary screen printing and digital printing. By first printing the dark background pattern (this color may also appear in delicate patterns) through the rotary screen, the fabric can obtain patterns with dark or high-color-level backgrounds, improving the color saturation and vividness of the fabric. Then, the remaining colors are combined through digital direct injection printing, making the patterns of the two integrate into one, and presenting delicate, rich, and vivid colors through digital direct injection printing. Finally, the finished fabric shows a color pattern with strong contrast and vivid colors. Such fabrics can be widely used in areas such as curtains, wall coverings, home fabrics, and high-end ready-to-wear, with excellent visual aesthetics.

[0027] In this solution, the dark background pattern is printed by a rotary screen, which can greatly relieve the working intensity of the direct injection nozzle and reduce the occurrence of ink bleeding or ink penetration on the fabric due to a large amount of ink injection. Therefore, the fineness of the finished fabric can be improved, the working efficiency of the nozzle can be greatly increased, and the service life of the nozzle can be extended, reducing its replacement and maintenance costs.

[0028] A registration method for combined rotary screen printing and digital printing in this solution can solve the problem that in traditional rotary screen printing with uniform linear fabric conveying and step-by-step direct injection printing, there is an easy occurrence of front-back deviation during fabric conveying, which in turn causes deviation in the overprinting of the two, greatly affecting the consistency of the fabric pattern. In this solution, within the same fabric cycle, the fabric is photographed, compared with the standard basic pattern, and then the specific value of the deviation is calculated. Corresponding fine-tuning operations can be performed according to the deviation value, greatly improving the consistency of fabric printing and reducing the occurrence of fabric waste. Brief Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the overall structure of the preferred embodiment.

[0030] Figure 2 It is a schematic diagram of the structure of the rotary screen printing mechanism.

[0031] Figure 3 It is a schematic diagram of the structure of the rotary conveying mechanism.

[0032] Figure 4 It is a schematic diagram of the structure of the digital printing mechanism.

[0033] Figure 5 It is a schematic diagram of the original printed pattern.

[0034] Figure 6 It is a schematic diagram of the first pattern.

[0035] Figure 7 It is a schematic diagram of the second pattern.

[0036] Figure 8 It is a schematic diagram of the basic pattern.

[0037] Figure 9 It is a schematic diagram of the superposition and comparison of the photographed pattern and the basic pattern. Detailed Description of the Invention

[0038] Refer to Figures 1 to 4 , a combined rotary screen printing and digital printing device, including a rotary screen printing mechanism 1 at the front end and a digital printing mechanism 2 arranged at the rear end of the rotary screen printing mechanism. The rotary screen printing mechanism 1 is used to present a dark background pattern on the fabric, and the digital printing mechanism 2 is used to present multi-color patterns on the fabric;

[0039] The rotary screen printing mechanism 1 includes at least one hollow thin-walled rotary screen roller 10. Below the rotary screen roller 10, a guide belt 11 and a support roller 12 are arranged. The fabric to be printed is evenly conveyed between the rotary screen roller 10 and the guide belt. Inside the rotary screen roller 10, a downward squeegee is arranged. The printing pigment inside it, under the extrusion of the squeegee, passes through the printing holes in the thin wall of the rotary screen roller 10 and is printed onto the surface of the fabric, forming a continuous cyclic printing operation. The support roller 12 is used for balanced support to make the printing surface of the fabric smoother.

[0040] Between the rotary screen printing mechanism 1 and the digital printing mechanism 2, a first oven 3 and a rotary conveying mechanism 4 are arranged. The first oven 3 is used for performing a basic drying operation on the fabric printed by the rotary screen printing mechanism 1, so that the printing pigment is firmly attached to the fabric.

[0041] To ensure the accuracy and smoothness of the printing operation, since the rotary screen printing mechanism 2 uses a uniform linear working method for printing and conveying the fabric, methods such as being too fast, too slow or intermittent conveying will mostly produce uneven colors on the fabric; while the digital printing mechanism 2 usually conveys in a stepping manner. Generally speaking, when the nozzle moves horizontally once or moves back and forth once, the fabric is conveyed forward by the length within the width range of the nozzle, thereby realizing a continuous and coherent direct printing operation; to balance the uniform conveying and the stepping conveying and make the conveying of the two coordinated and not interfere with each other, a rotary conveying mechanism 4 is arranged at the rear end of the first oven 3. It includes an adjusting roller 41 that can freely move up and down. Both ends of the adjusting roller 41 are connected to a straight rod 43 through bearings and sliders 42. Therefore, the slider 42 can freely displace up and down on the straight rod 43 in a manner with extremely low damping. The adjusting roller 41 is arranged inside the fabric in a V-shaped transmission. Therefore, under the action of its gravity, the fabric is always in a V-shaped rotary conveying state. This V-shaped rotary conveying structure is used to accommodate the fabric and make the uniform conveying and the stepping conveying of the fabric carried out in a coordinated manner.

[0042] The digital printing mechanism 2 includes a printing main body and a nozzle component 21. The nozzle component 21 is connected with an ink pipeline, and the nozzle component is connected with a horizontal reciprocating driving component. Under the control of the printing main body, by analyzing the picture to be printed, the nozzle component and the horizontal reciprocating driving component are controlled to implement the printing operation of the pattern; below the nozzle component, a smooth table board 22 is arranged. The fabric to be printed is arranged between the nozzle component 21 and the table board 22.

[0043] In the digital printing mechanism 2, especially at the front end and the rear end of the nozzle component 21, there are fabric direct injection conveying mechanisms 23 arranged. The fabric direct injection conveying mechanisms 23 are all in the form of clamping roller shafts for conveying. It includes a pair of roller shafts that are in an upper and lower clamping state. The fabric is conveyed between the two, and it is ensured that between the two, the fabric is conveyed in a straight and reasonable tension manner. The roller shafts of the fabric direct injection conveying mechanism 23 are connected with high-precision servo motors and precise angle sensors, which can precisely control the rotation of its roller shafts, the rotation angle and the rotation speed, and make the fabric direct injection conveying mechanisms 23 at the front end and the rear end perform synchronous rotation operations.

[0044] Under the control of the printing main machine, the fabric is conveyed forward step by step through the fabric direct injection conveying mechanism 23. Generally speaking, the step amplitude is consistent with the printing width of the nozzle component 21. Usually, when the nozzle component 21 moves from one side to the other side (completing an inkjet printing operation), the fabric direct injection conveying mechanism 23 conveys the fabric forward by one printing unit, and the digital printing operation is carried out in this way repeatedly.

[0045] At the front end of the digital printing mechanism 2, there is a printing alignment mechanism 5 arranged. The printing alignment mechanism 5 includes a camera, and the camera is connected with the printing main machine. Specifically, the camera is arranged at the front end of the nozzle component, and the distance between the center point of the camera and the nozzle component is consistent with the distance between the single pattern cycles of the rotary screen printing (for the single pattern cycle of the rotary screen printing, it can be understood that when the rotary screen rotates one week, the patterns before and after can just be connected to achieve continuous and non-interval patterns). Therefore, the pattern corresponding to the center point of the camera is the pattern for the current nozzle component 21 to perform the inkjet operation, so as to realize the synchronization of the camera taking samples and the current inkjet printing.

[0046] The fabric performs inkjet printing operation at the digital printing mechanism 2 and cooperates with the background color printing of the rotary screen printing mechanism 1 to achieve complete pattern printing, so that the fabric presents a complete and clear design pattern. After the fabric completes subsequent processes such as drying and shaping, the entire printing operation is completed.

[0047] A rotary screen printing and digital printing combined printing method in this solution is used to decompose the original printed image to make it suitable for the rotary screen printing and digital printing combined printing, including:

[0048] Perform color separation processing on the original printed pattern with a cyclic structure (refer to Figure 5 ), select the background pattern, generate a monochromatic first pattern (refer to Figure 6 ), make a rotary screen according to the first pattern, and mix the color of the first pattern to prepare the corresponding pigment, and place the pigment inside the rotary screen of the rotary screen printing mechanism;

[0049] After removing the first pattern part from the original pattern, generate a second pattern (refer toFigure 7 ), perform YMCK color separation on the second pattern to produce a set of YMCK patterns, and respectively configure the set of YMCK patterns to the print heads for corresponding direct printing operations.

[0050] In order to better integrate the first pattern with the digital printing pattern and reduce the occurrence of blank gaps at the junction of the two, when generating the first pattern, reserve a certain coverage area on its outer contour that can coincide with the edge of the second pattern, and perform a color reduction process on the color of this coverage area in the first pattern. Specifically, the coverage area can be sampled 1-2 pixel intervals inward and expanded 2-3 pixel intervals outward based on the edge. When performing the color reduction process on this coverage area, according to the YMCK printing principle, it is carried out from the inside to the outside, and its printing dots are implemented in a progressive manner from a large-diameter dense structure to a small-diameter sparse structure.

[0051] Due to differences in fabric conveyance (constant-speed conveyance and step-by-step conveyance), it is easy to cause the fabric to be difficult to align when it reaches the digital printing area after rotary screen printing. At the same time, due to long-term printing operations, the initially slight conveyance deviation will cause the error to be continuously enlarged, resulting in a printing deviation between the two and causing defects in the finished fabric.

[0052] This solution uses a camera to capture a specified base pattern on the fabric after rotary screen printing. The printing host receives the pattern collected by the camera, processes it, and then compares it with the pattern to be processed by the digital printing mechanism. When the two patterns are not aligned, the processor controls the fabric direct printing conveyance mechanism to perform corresponding fine-tuning operations on the fabric at the digital printing mechanism 2.

[0053] Specifically, an alignment method for combined rotary screen printing and digital printing includes:

[0054] Select an area with characteristics in the first pattern to generate a base pattern (reference Figure 8 ), the base pattern with distinguishable characteristics appears only once on a straight line in a single pattern cycle, and it includes at least two front and back base feature points A and B on the straight line, and measure the actual distance value H between the two base feature points;

[0055] Arrange the center point of the camera at the front end of the print head component, and make the distance between the two consistent with the distance between a single fabric cycle of rotary screen printing. The center point of the camera is arranged directly above the midpoint of the base feature points A and B, and its camera field of view can completely cover the two points A and B, and ensure that when shooting, reduce situations such as distortion or aberration. If necessary, soft light, etc. are arranged around the camera to improve the lighting conditions;

[0056] When the basic pattern part of the fabric is conveyed to the center point of the camera, the camera captures the basic pattern area of the fabric. This capture operation should be in a stopped state during the intermittent conveyance of the fabric, generating a captured pattern. The processor of the printing host obtains this captured pattern and compares it with the basic pattern in a center-aligned manner (refer to Figure 9 ). During the comparison operation, edge detection can be performed on the basic pattern and the captured pattern to obtain corresponding patterns that only include the image edge lines. Figure 9 The blue dot in Figure 9 is the position of point A in the captured pattern. Therefore, based on the positional relationship of the blue dot in the H straight line and the actual distance value H, the deviation value H1 between the captured pattern and the basic pattern is calculated.

[0057] When the deviation value H1 is less than or equal to the preset minimum deviation value, usually, this minimum deviation value can be 0.2 mm. Then, the impact of this deviation on the pattern is not significant, and the original digital printing operation can continue.

[0058] When the deviation value H1 is greater than the preset maximum deviation value, usually, this maximum deviation value can be 4.0 mm, that is, the nozzle of the digital printing is in a severely misaligned state with the pattern of the rotary screen printing, and the pattern cannot be corrected by gradual fine-tuning. Then, the printing host controls the fabric direct injection conveying mechanism 23, and during the interval when the nozzle reciprocates, the fabric is adjusted forward or backward, and the adjustment is made based on the deviation value H1 to ensure that the next direct injection printing is aligned with the rotary screen printing. It should be noted that due to the large direct adjustment, part of the pattern will be in a severely misaligned state, and this section of the fabric is in a defective state. Of course, this state rarely occurs, usually at the initial stage of starting digital printing.

[0059] When the deviation value H1 is less than or equal to the set maximum deviation value, that is, the nozzle of the digital printing is in a slightly misaligned state with the pattern of the rotary screen printing. The printing host divides the deviation value H1 by the number of reciprocations N of the nozzle in a single pattern cycle to obtain the single adjustment value. The printing host controls the fabric direct injection conveying mechanism, and during each interval when the nozzle reciprocates, the fabric is finely adjusted forward or backward with the single adjustment value, and at the end of this single fabric cycle, the captured pattern and the basic pattern are aligned.

[0060] So far, through the alignment method of the combined printing of rotary screen printing and digital printing in this solution, whether at the initial stage or during the process of digital printing, the precise alignment of the two can be ensured by capturing and comparing the basic pattern with the camera, so as to achieve fine pattern restoration. Through the alignment operation in each printing cycle, the operation is more controllable and convenient.

[0061] In summary, for the printing device combining rotary screen printing and digital printing in this solution, by first printing the dark background pattern (this color may also appear in delicate patterns) through the rotary screen, the fabric can obtain patterns with a dark or high-color-level background, improving the color saturation and vividness of the fabric. Subsequently, the remaining colors are combined through digital direct-injection printing, enabling the integration of the patterns of the two, and presenting delicate, rich colors through digital direct-injection printing. Ultimately, the finished fabric exhibits a color pattern with strong contrast and vivid colors. Such fabrics can be widely used in applications such as curtains, wall coverings, home fabrics, and high-end ready-to-wear, possessing excellent visual aesthetics.

[0062] In this solution, printing the dark background pattern by the rotary screen can greatly alleviate the working intensity of the direct-injection nozzle and reduce the occurrence of ink bleeding or ink penetration on the fabric due to a large amount of ink spraying. Therefore, it can improve the fineness of the finished fabric, significantly enhance the working efficiency of the nozzle, and extend the service life of the nozzle, reducing its replacement and maintenance costs.

[0063] For the alignment method of the printing combining rotary screen printing and digital printing in this solution, it can solve the problem that in traditional rotary screen printing with uniform linear fabric conveyance and step-by-step direct-injection printing, there is an easy occurrence of front-back deviation during fabric conveyance, thereby causing deviation in the overprinting of the two and greatly affecting the consistency of the fabric pattern. In this solution, within the same fabric cycle, the fabric is photographed, compared with the standard basic pattern, and the specific value of the technical deviation can be obtained. Corresponding fine-tuning operations can be performed according to the deviation value, greatly improving the consistency of fabric printing and reducing the occurrence of fabric waste.

Claims

1. A printing method combining rotary screen printing and digital printing, which is applied to a printing device combining rotary screen printing and digital printing, and is characterized in that: The printing device includes a rotary screen printing mechanism at the front end and a digital printing mechanism arranged at the rear end of the rotary screen printing mechanism. The rotary screen printing mechanism is used to present a dark background pattern on the fabric, and the digital printing mechanism is used to present a multicolor pattern on the fabric; A first oven and a rotary conveying mechanism are arranged between the rotary screen printing mechanism and the digital printing mechanism. Fabric direct injection conveying mechanisms are arranged at the front end and the rear end of the digital printing mechanism, and a printing alignment mechanism is arranged at the front end of the digital printing mechanism; The printing alignment mechanism includes a camera and a controller. The camera is used to photograph a specified basic pattern on the fabric after rotary screen printing; The camera is arranged at the front end of the nozzle component, and the distance between the center point of the camera and the nozzle component is the same as the distance between single-pattern cycles of rotary screen printing; The printing method includes: Perform color separation on the original printed pattern with a cyclic structure, select the background pattern, generate a monochromatic first pattern, make a rotary screen according to the first pattern, and mix the corresponding pigments according to the color of the first pattern, and place the pigments into the rotary screen inside the rotary screen printing mechanism; After removing the first pattern part from the original pattern, generate a second pattern, perform YMCK color separation on the second pattern, produce a YMCK pattern group, and configure the YMCK pattern group to the nozzles for corresponding direct injection operations; Select a characteristic area in the first pattern to generate a basic pattern. The basic pattern with distinguishable features appears only once on a straight line in a single pattern cycle, and it includes at least two front and rear basic feature points on the straight line, and measure the actual distance value between the two basic feature points; When the basic pattern part of the fabric is conveyed into the center point of the camera, the camera photographs the basic pattern area of the fabric to generate a photographed pattern. The processor of the printing host obtains the photographed pattern and compares it with the basic pattern in a center-aligned manner. During the comparison operation, perform edge finding on the basic pattern and the photographed pattern to obtain corresponding patterns that only include the image edge lines, and calculate the deviation value between the photographed pattern and the basic pattern based on the actual distance value; When the deviation value is less than or equal to the preset minimum deviation value, continue to maintain the original digital printing operation; When the deviation value is greater than the preset maximum deviation value, the printing host controls the fabric direct injection conveying mechanism, and adjusts the fabric forward or backward during the gap when the nozzle reciprocates, and adjusts it according to the deviation value; When the deviation value is greater than the preset minimum deviation value and less than or equal to the set maximum deviation value, the printing host divides the deviation value by the number of reciprocations of the nozzle in a single pattern cycle to obtain a single adjustment value, and the printing host controls the fabric direct injection conveying mechanism to finely adjust the fabric forward or backward by the single adjustment value during each gap when the nozzle reciprocates.

2. The combined printing method of rotary screen printing and digital printing according to claim 1, characterized in that: The digital printing mechanism includes a printing main machine and a nozzle component. A smooth platen is arranged below the nozzle component, and the fabric to be printed is arranged between the nozzle component and the platen. The fabric direct-injection conveying mechanism is arranged at the front and rear ends of the platen, and enables the fabric to be printed to be in a flat conveying state between the two.

3. A combined printing method of rotary screen printing and digital printing according to claim 1, characterized in that: The rotary conveying mechanism includes an adjusting roller shaft that can freely move up and down. The two ends of the adjusting roller shaft are connected to the straight rod through bearings and sliders.

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