Ink-jet printing method for braid

Abstract

The invention discloses a braid ink-jet printing method which is used for printing braid media with concave-convex surfaces, the printing process comprises a conveying stage, a measuring stage, a filling and leveling stage and an image-text printing stage, in the conveying stage, a whole roll of braid is intermittently conveyed, and in the interval when the braid stops conveying, the braid ink-jet printing method is used for printing the braid media with the concave-convex surfaces. In the measurement stage, height data of different positions of the surface of the braid are measured by using a 3D camera, and in the filling stage, the height data of different positions of the surface of the braid are calculated according to an obtained relation curve of'jet density ink quantity and ink superposition height '. And the filling effect is achieved by controlling spraying of ink with corresponding densities at different height positions on the surface of the braid, and finally the image-text printing stage is conducted to complete image-text printing on the surface of the braid. According to the invention, the concave-convex difference of the surface of the medium is measured through the 3D camera, and then targeted filling and leveling processing and subsequent image-text printing are carried out according to a software algorithm, so that the inkjet effect on the special medium is ensured, and the application field of inkjet printing is expanded.

Description

Technical Field

[0001] This invention relates to a method for inkjet printing webbing, and more particularly to a method for pre-filling a webbing with an uneven surface before printing the graphic. Background Technology

[0002] Currently, inkjet printers typically print on flat media. However, with the increasing demand for inkjet printing, some types of media, such as webbing, also require inkjet printing. This is because webbing is made from yarn and consists of narrow-width or tubular fabrics, similar to... Figure 1 The medium shown has a surface with an uneven texture, and its microstructure is as follows: Figure 2 As shown, the surface of the webbing includes a highest point 1, a lowest point 2, and various positions at different heights between the highest point 1 and the lowest point 2. Traditional inkjet printing technology can only directly spray ink droplets onto its surface to form images. Although the ink droplets will flow and spread, the printed images will still exhibit a visually uneven appearance due to the surface's surface texture, resulting in poor print quality. To avoid the above problems, it is necessary to develop a pre-treatment method that uses software to fill the uneven surface of the medium. This allows the webbing surface to be first filled with ink droplets to form a flat surface, and then images can be printed on this flat surface to achieve a high-quality print effect. Summary of the Invention

[0003] The purpose of this invention is to overcome the defects in the prior art and provide a software printing method for webbing, which first fills the surface of the webbing and then prints the required graphics and text.

[0004] The above-mentioned technical problem of the present invention is solved by the following technical solution: a method for inkjet printing webbing is proposed, characterized by including a conveying stage, a measurement stage, a leveling stage, and a graphic printing stage. The working steps are as follows: a) Conveying stage: the paper receiving module winds up the webbing to be printed, and the paper releasing module releases the webbing to be printed. After the webbing to be printed has been conveyed for the length of one printing table, the conveying of the webbing to be printed stops; b) Measurement stage: the printhead module moves along the crossbeam from an initial position at one end to an end position at the other end. A 3D camera installed on one side of the printhead module measures and feeds back the height data of different positions on the surface of the webbing to be printed. During this process, the printhead does not eject ink droplets. After the measurement is completed, the printhead module moves along the crossbeam from the end position to the initial position; c) Leveling stage: the printhead module moves along the crossbeam again from an initial position at one end to an end position at the other end. The software controls the nozzles below the printhead module to eject ink droplets based on the height data fed back by the 3D camera, which is used to quickly fill the concave areas on the surface of the webbing to be printed. After the printhead module reaches the endpoint, it moves along the crossbeam from the endpoint to the initial position. Similarly, the software controls the nozzles below the printhead module to eject ink droplets based on the height data fed back by the 3D camera. d) The software determines whether the filling of a desktop of webbing to be printed is complete. If not, repeat steps c)-d). If yes, proceed to step e). e) In the image and text printing stage, the printhead module moves along the crossbeam again. When the printhead reaches above the image and text area to be printed on the webbing, it ejects ink droplets to form the required image and text, completing the printing job for this desktop. f) After all the jobs for a desktop length are completed, the software determines whether the entire roll of webbing to be printed is printed. If not, proceed to steps a)-f). If yes, end the printing.

[0005] In the above method for inkjet printing webbing, the measurement stage in step b) further includes obtaining the relationship curve between "jet density ink volume and ink stacking height", that is, obtaining the stacking height value of ink for a single print when the printhead jets ink volumes of different densities.

[0006] In the above-mentioned method for inkjet printing webbing, the method for obtaining the relationship curve between "jetting density ink volume and ink superposition height" is as follows: On a flat fixture, color blocks with different ink densities are jetted, and the height of the printed color blocks is measured at 100% ink density, 90% ink density, 80% ink density, 70% ink density, 60% ink density, 50% ink density, 40% ink density, 30% ink density, 20% ink density, and 10% ink density. A line graph showing the relationship between different ink densities and the height of the printed color blocks is obtained. Then, the line graph is corrected using a Bezier curve to obtain a smooth curve showing the relationship between jetting density ink volume and ink superposition height.

[0007] In the above-mentioned inkjet printing method for ribbon, the Bézier curve correction is performed using a recursive interpolation method.

[0008] In the above-mentioned inkjet printing method for ribbon, the recursive interpolation includes an initial stage, first interpolation, second interpolation, and third interpolation.

[0009] In the above-mentioned inkjet printing method for webbing, the printing method of step c) the leveling stage is calculated by software: First, the number of scan printing passes N required for the leveling stage is calculated, N = H MAX ÷ the ink stacking height of a single pass when spraying 100% density ink volume, where H MAX represents the height value of the lowest point on the webbing surface; then, the height data of different positions on the webbing surface measured and fed back by the 3D camera are divided by the number of printing passes N to obtain the ink stacking height value required for a single pass of printing at different positions of the webbing; then, according to the relationship curve between "spraying density ink volume and ink stacking height", the inkjet density ink volume corresponding to the ink stacking height value is obtained, and the inkjet density ink volume is used to control the inkjet operation of different printhead nozzles at corresponding positions.

[0010] In the above-mentioned inkjet printing method for webbing, when filling the lowest point of the webbing surface to be printed, all printhead nozzles spray ink simultaneously, that is, spray 100% density ink volume; when filling, no ink droplets are sprayed at the highest point of the webbing surface.

[0011] In the above-described inkjet printing method for ribbon, during step c) the leveling stage, the printhead uses large ink droplets for inkjet printing.

[0012] In the above-mentioned inkjet printing method for webbing, in step e) the image printing stage, the printhead can spray ink droplets again during the return process to form the required image, or it can not spray ink droplets during the return process, or a micro-stepping printing method can be used, that is, after the printhead module reaches one end of the crossbeam, it makes a small step perpendicular to the conveying direction and then performs scanning inkjet printing again.

[0013] In the above-described inkjet printing method for ribbon, during steps c) and e), the curing device is opened to cure the ink below during the inkjet process.

[0014] The beneficial effects of this invention are as follows: A contour measuring device, i.e., a 3D camera, is used to detect the surface of the ribbon to be printed, obtaining height information at various locations on the surface. Based on this height data, the ink first fills the recesses in the ribbon before printing the required graphics, thus ensuring the quality of the printed graphics. Before the filling operation, a line graph showing the relationship between "jet density ink volume and ink superposition height" is obtained through measurement. This line graph is then corrected using a Bezier curve to ensure accurate ink volume for filling different height positions, guaranteeing the filling effect and consequently ensuring the printing quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the printing medium, webbing, being printed by the inkjet printer of this invention; Figure 2 This is a microscopic schematic diagram of the surface of the printing medium of the inkjet printer of the present invention; Figure 3 This is a perspective view of an inkjet printing device in a specific embodiment of the present invention; Figure 4 For the present invention Figure 3 A 3D illustration showing the flip-up cover hidden; Figure 5 This is a flowchart of a printing method in one embodiment of the present invention; Figure 6 This is a partial list of the surface height values ​​of the medium obtained after the 3D camera of the present invention scans the medium to be printed. Figure 7 Schematic diagram of ink ejection from the nozzle at 100% and 50% ink density. Figure 8 A schematic diagram comparing the height of ink droplet stacking when spraying 100% density ink volume and 50% density ink volume; Figure 9 A schematic diagram illustrating the stacking height of ink droplets of different densities sprayed onto a flat fixture. Figure 10 This is a line graph showing the relationship between "jet density ink volume and ink stacking height" in a calibration embodiment. Figure 11 for Figure 10 A smooth curve showing the relationship between jet density, ink volume, and ink stacking height after Bessel correction; Figure 12 This is a schematic diagram illustrating the calculation of the number of passes required for leveling based on the height of the lowest point on the medium surface. Figure 13 This is a schematic diagram illustrating the principle of multiple filling operations on a medium with five height positions.

[0016] The numbers in the diagram represent: 1. Highest point of the webbing surface; 2. Lowest point of the webbing surface; 0. Nozzle module; 3. Paper collection module; 4. 3D camera; 5. Printing platform; 6. Curing device; 7. Crossbeam; 8. Medium to be printed; 9. Paper feeding module; 10. Top cover; S1. Lowest position of the medium surface; S4. Highest position; S2. Middle height position; S3. Middle height position; S5. N1 indicates the height increase after the first scan and printing; N2 indicates the height increase after the second scan and printing; N3 indicates the height increase after the third scan and printing. The diagram illustrates the increased height after printing. N4 represents the increased height after the fourth layer of filling and printing; N5 represents the increased height after the fifth layer of filling and printing; N6 represents the increased height after the sixth layer of filling and printing; N7 represents the increased height after the seventh layer of filling and printing; N8 represents the increased height after the eighth layer of filling and printing; N9 represents the increased height after the ninth layer of filling and printing; and N10 represents the increased height after the tenth layer of filling and printing. Detailed Implementation

[0017] The method for inkjet printing webbing according to the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0018] like Figure 3-4 As shown, this invention illustrates an embodiment of an inkjet printing device for printing on webbing. This inkjet printing device can first fill in the uneven areas on the surface of the webbing before printing the image. The inkjet printing device includes a printhead module 0, a paper take-up module 3, a 3D camera 4, a printing platform 5, a curing device 6, a crossbeam 7, and a paper feeding module 9. The paper feeding module 9 and the paper take-up module 3 are respectively located on the left and right sides of the bottom of the inkjet printing device. A roll of printing medium 8 is first mounted on the paper feeding module 9. The printing medium 8 passes through components such as guide rollers and tension bars (not shown in the figure) and then through the printing platform 5 before being wound onto the paper feeding module 3. During the printing operation, the paper feeding module 3 winds the printed printing medium 8 onto itself, while the paper feeding module 9 continuously releases the printing medium 8. In this invention, the printing medium 8 is webbing with uneven surface characteristics. Figure 3After the top cover 10 is turned up, the printing platform 5 can be seen above the paper receiving module 3 and the paper feeding module 9. The printing medium 8 passes above the printing platform 5. A crossbeam 7 is set above the printing platform along the conveying direction of the printing medium 8. A nozzle module 0 is installed on the crossbeam 7. The nozzle module 0 can reciprocate along the crossbeam 7. A nozzle (not shown in the figure) is installed below the nozzle module 0. The length direction of the nozzle is perpendicular to the conveying direction of the printing medium 8. The nozzle sprays ink droplets onto the printing medium 8 below to form images. A curing device 6 is installed on the side of the nozzle module 0. The curing device 6 is used to cure the ink droplets sprayed onto the surface of the printing medium 8. A 3D camera 4 is installed on the side of the nozzle module 0 near the paper feeding module 9. The 3D camera 4 is used to measure the height data of different positions on the surface of the printing medium 8 below. In addition to the above structure, the printing device also includes a doctor blade maintenance module, an air and ink path control box, and an electrical box module. The doctor blade maintenance module is used to perform doctor blade maintenance on the printhead. The air and ink path control box and the electrical box are used to control the inkjet and conveying operations of the printing device. These modules are hidden inside the machine and are not shown in the figure.

[0019] The following is based on Figure 5This section describes the working process of the printing device. The process consists of four stages: the transport stage, the measurement stage, the leveling stage, and the image printing stage. After the operator installs the printing medium 8, they click the start button, and the printing device enters the transport stage: the paper take-up module 3 begins to wind up the printing medium 8, and the paper release module 9 releases the printing medium 8. The printing medium 8 is transported for the length of the printing tabletop. At this time, the printing medium 8 is above the printing platform 5, and the paper take-up module 3 and the paper release module 9 stop working, and the transport of the printing medium 8 stops. The measurement stage then begins: the printhead module 0 moves along the crossbeam 7 from its initial position at one end to its final position at the other end. Simultaneously, the 3D camera 4 installed on one side of the printhead module 0 measures and reports the height data of different positions on the surface of the printing medium 8 below. During this process, the printhead does not eject ink droplets. After the measurement is completed, the printhead module 0 moves along the crossbeam 7 from its final position back to its initial position. Next, the leveling stage begins: the printhead module 0 moves along the crossbeam 7 from its initial position to its final position. Based on the height data fed back by the 3D camera 4, the software controls the printhead on the printhead module 0 to spray ink droplets of the corresponding density to quickly fill the depressions on the surface of the printing medium 8. After the printhead module 0 reaches the final position, it moves along the crossbeam 7 back to its initial position. Similarly, based on the height data fed back by the 3D camera 4, the software controls the printhead on the printhead module 0 to spray ink droplets of the corresponding density. The software determines whether the leveling of a desktop printing medium 8 is complete. If not, the leveling stage process is repeated until the surface of the printing medium 8 is filled with ink droplets. If yes, the next graphic printing stage begins. The image and text printing stage: The printhead module 0 moves along the crossbeam 7 from its initial position to its final position. When the printhead reaches the area of ​​the image to be printed on the medium 8, it ejects ink droplets to form the desired image and text, completing the desktop printing job. During the return process of the printhead module 0 moving along the crossbeam 7 from the final position to the initial position, the printhead can eject ink droplets again to form the desired image and text, or it can not eject ink droplets during the return process. The actual situation depends on the printing requirements. In addition, a micro-stepping printing method can also be used. That is, after the printhead module 0 reaches one end of the crossbeam, it takes a small step perpendicular to the conveying direction and then performs scanning inkjet printing again to stagger the ink droplets printed in the previous pass, thereby improving the resolution. After all the printing operations for one desktop length are completed, the software determines whether the entire roll of printing media 8 has been printed. If not, it re-enters the conveying stage. The paper receiving module 3 begins to reel in the printing media 8, and the paper releasing module 9 releases the printing media 8. The printing media 8 is conveyed for another desktop length before stopping, and the above measurement, leveling, and image printing stages are repeated until the entire roll of printing media 8 has been printed. If so, the entire roll of printing media 8 has been printed and can be unloaded. During the inkjet process, the curing device 6 next to the printhead module 0 operates to cure the ink below.

[0020] The following describes in detail the operation process of the measurement and leveling stages of the inkjet printing device, based on an embodiment.

[0021] As the printhead module 0 moves along the crossbeam 7 from its initial position at one end to its final position at the other, the 3D camera 4 mounted on one side of the printhead module 0 measures and feeds back the height data of different positions on the surface of the printing medium 8, generating a table. For example... Figure 6 The image shows a portion of the data in the table. Each value in the table represents the height (in millimeters) of a point on the surface of the printing medium 8. For example, the maximum value of 1.5mm in the table represents... Figure 2 The table shows the height of position 2, the lowest point on the surface of the ribbon of the object to be printed. The minimum value of 1.4mm in the table represents... Figure 2 The height value at position 1, the highest point on the surface of the ribbon of the object to be printed.

[0022] After the 3D camera 4 measures and returns the height data of the surface of the printing medium 8, the software calculates the ink density required for leveling at different height locations based on this height data. Specifically, the software calculates the highest and lowest points based on the height data table. No ink droplets are ejected at the highest point 1 on the webbing surface, while all printheads simultaneously eject ink at the lowest point 2, resulting in the maximum number of ink droplets ejected, defined as 100% ink density. At different height locations between the highest point 1 and the lowest point 2 on the webbing surface, the printheads are controlled to eject ink of different densities according to the relationship curve between "ink density and ink superposition height" to complete the leveling operation.

[0023] The following details how to obtain the relationship curve between "jet density, ink volume, and ink stacking height".

[0024] In theory, the ink jet density is directly proportional to the height of the ink layer. Taking 100% and 50% ink density as examples, 100% ink density means all nozzles of the printhead spray ink at this position. After the ink hits the printing medium 8, it diffuses and merges, ultimately forming a relatively high plane. 50% ink density means only 50% of the nozzles of the printhead spray ink at this position, resulting in a relatively lower height of the merged ink plane. Figure 7 This diagram illustrates ink ejection from the printhead nozzles at 100% and 50% ink density. ○ indicates ink ejection from the nozzle, and × indicates no ink ejection. Figure 8 This diagram illustrates the comparison of droplet height when spraying ink at 100% and 50% ink density. In terms of printing results, the ink droplet height is darkest at 100% ink density, appearing as black, while at 50% ink density, the ink droplet height is lighter, appearing as gray.

[0025] In practice, the ink density and ink stacking height are not necessarily linearly positively correlated. Therefore, we calibrate it by spraying color blocks of different ink densities onto a flat fixture. Figure 9 As shown, the height of the printed color blocks was measured at ink densities of 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, and 10% to obtain the relationship between the ink jet density and the printed color block height. Since the height of a single ink pass is difficult to measure and has a large error, the total height was measured after multiple print passes, and then divided by the number of print passes to obtain the cumulative height of a single ink pass corresponding to different ink density levels. Figure 10 As shown, the vertical axis represents the numerical value of the single-pass ink droplet stacking height in millimeters (mm), and the horizontal axis represents the ink density of the jet. The measured values ​​show that the jet density ink density and the ink stacking height are not linearly positively correlated. For example, when the jet density ink density is 50%, the single-pass ink stacking height is 0.4 mm, which is not half of the 1 mm single-pass ink stacking height when the jet density ink density is 100%.

[0026] Based on the above measurements, connecting the ink stacking height values ​​for different ink spray densities yields a broken line. If ink is applied strictly according to the relationships on this broken line, the printed image quality is unsatisfactory. Therefore, we use Bézier curves to correct this, resulting in a new, smooth curve. Bézier curve correction is a smooth curve whose shape is defined by "control points." It uses mathematical formulas (polynomial functions) to describe the curve's trajectory, and the curve's shape is entirely determined by the "start point," "end point," and several "intermediate control points." The control points do not fall directly on the curve, but they influence the curve's bending direction and smoothness through "tension." Furthermore, the curve always remains within the "convex hull" (minimum enclosing polygon) formed by all control points, thus ensuring the predictability of its shape.

[0027] The drawing and calculation of Bézier curves mainly rely on the de Castellio algorithm, an intuitive "recursive interpolation" method that can quickly determine the position of any point on the curve. Taking a cubic Bézier curve as an example, the algorithm steps include an initial stage, first-order interpolation, second-order interpolation, and third-order interpolation. Specifically, the initial line segments are: connecting four control points to form three initial line segments, denoted as S-P1, P1-P2, and P2-E. First-order interpolation involves taking one point on each initial line segment (at a fixed ratio t, t∈[0,1]), resulting in three new points: point A (point t on line segment S-P1), point B (point t on line segment P1-P2), and point C (point t on line segment P2-E). Second-order interpolation involves connecting AB and BC to form two new line segments, and then taking points at the same ratio t to obtain two new points: point D (point t on line segment AB) and point E (point t on line segment BC). Third-order interpolation involves connecting DE and taking points at the ratio t to obtain the final point P. This point P is the point on the Bézier curve corresponding to the parameter t. As t changes continuously from 0 to 1, countless points P constitute a complete Bézier curve (when t=0, P=S; when t=1, P=E).

[0028] After the above Bézier curve correction, we get Figure 11 The curve showing the relationship between "jet density ink volume and ink stacking height" is shown, where the vertical axis represents the ink stacking height in millimeters (mm), and the horizontal axis represents the jet density ink volume.

[0029] In the early stages of the leveling phase, the software also needs to calculate the number of printhead scans required for the leveling phase, such as... Figure 12 As shown, the height of the lowest point 2 on the media surface is defined as HMAX, and the number of printing passes required to fill it is denoted as N. N = HMAX ÷ the height of a single ink pass when spraying 100% density ink volume. The height of a single ink pass when spraying 100% density ink volume is the correction curve. Figure 11 The corresponding vertical coordinate height value is then calculated. Next, the other height data measured and fed back by the 3D camera 4 at different locations on the surface of the printing medium 8 are divided by the number of printing passes N to obtain the ink stacking height value required for a single print pass at different locations on the printing medium 8. Then, based on the correction curve... Figure 11 Find the horizontal coordinate corresponding to the ink stacking height value, that is, the inkjet density and ink volume. Use the inkjet density and ink volume to control the inkjet operation of different printhead nozzles at the corresponding positions. That is, different positions on the surface of the printing medium 8 correspond to different ink densities and volumes, and finally complete the operation effect of filling the surface of the medium after N scans and prints.

[0030] During the process of the printhead module 0 moving along the crossbeam 7 from its initial position at one end to its final position at the other end, the ink droplet ejection at each position is controlled according to the different ink density amounts in the aforementioned correction curve. Figure 13The specific implementation example is described below. In this example, the media surface area includes five different height positions: the lowest position S1, the highest position S4, and the three middle height positions S2, S3, and S5. The number of printing passes required for the leveling operation is obtained by dividing the height value of the lowest position S1, which is measured and fed back by the 3D camera, by the single ink stacking height when the ink volume of the jet density is 100%. This embodiment illustrates that ten print passes are required to complete the leveling operation. In each pass, the print head sprays different density ink volumes at different positions. At the lowest position S1, 100% density ink volume is sprayed. At the highest position S4, no ink droplets are sprayed from the nozzle. At the three middle height positions S2, S3, and S5, the same corresponding density ink volume is sprayed in each scan. The corresponding density ink volume is calculated by dividing the height value of the position measured by the 3D camera by the number of print passes (ten in this embodiment) to obtain the ink stacking height required for a single print pass. Then, the spray density ink volume corresponding to the ink stacking height of a single print pass is obtained according to the "spray density ink volume and ink stacking height" correction curve. The software controls the print head to spray the corresponding density ink volume at the position, ultimately achieving a leveling effect where the entire surface of the medium is at the same height. In the diagram, N1 represents the height increase after the first scan and leveling printing of each position; N2 represents the height increase after the second scan and leveling printing of each position; N3 represents the height increase after the third scan and leveling printing of each position; N4 represents the height increase after the fourth scan and leveling printing of each position; N5 represents the height increase after the fifth scan and leveling printing of each position; N6 represents the height increase after the sixth scan and leveling printing of each position; N7 represents the height increase after the seventh scan and leveling printing of each position; N8 represents the height increase after the eighth scan and leveling printing of each position; N9 represents the height increase after the ninth scan and leveling printing of each position; and N10 represents the height increase after the tenth scan and leveling printing of each position. After the tenth scan and leveling printing is completed, the upper surface height of all positions on the medium is flush, that is, consistent with the height of the highest position S4.

[0031] It should be noted that during the leveling stage, the nozzles use large ink droplets for ink spraying. When large ink droplets are sprayed, the printhead sprays more ink in a single stroke, covering a larger area, thus resulting in higher leveling efficiency.

[0032] After the surface of the printing medium 8 is leveled, the printhead module 0 moves along the crossbeam 7 again and performs inkjet printing, completing the graphic printing stage of the printing medium 8. At this point, one table of media has been printed. The control system controls the conveying device to convey another table of media length and then stops conveying, continuing to repeat the above measurement stage, leveling stage, and graphic printing stage operations, in this cycle until all the printing media 8 have been processed.

[0033] It should be noted that any modifications made according to the specific embodiments of the present invention do not depart from the spirit of the present invention and the scope of the claims.

Claims

1. A method for inkjet printing webbing, characterized in that, The work includes the transmission stage, measurement stage, leveling stage, and graphic printing stage. The steps are as follows: a) During the conveying phase, the paper receiving module winds up the tape to be printed, the paper releasing module releases the tape to be printed, and the tape to be printed stops conveying after being conveyed for the length of one printing table. b) During the measurement phase, the printhead module moves along the crossbeam from the initial position at one end to the final position at the other end. The 3D camera installed on one side of the printhead module measures and feeds back the height data of different positions on the surface of the ribbon to be printed. During this process, the printhead does not eject ink droplets. After the measurement is completed, the printhead module moves along the crossbeam from the final position to the initial position. c) During the leveling stage, the printhead module moves along the crossbeam from the initial position at one end to the final position at the other end. The software controls the printhead below the printhead module to eject ink droplets based on the height data fed back by the 3D camera, which is used to quickly level the concave areas on the surface of the ribbon to be printed. After the printhead module reaches the final position, it moves along the crossbeam from the final position to the initial position. Similarly, the software controls the printhead below the printhead module to eject ink droplets based on the height data fed back by the 3D camera. d) The software determines whether the filling of a desktop of webbing to be printed has been completed. If not, repeat steps c)-d); if yes, proceed to step e). e) During the graphic printing stage, the printhead module moves along the crossbeam again. When the printhead reaches the area above the graphic area to be printed on the webbing, it ejects ink droplets to form the desired graphic, thus completing the printing job on this desktop. f) After all jobs for a desktop length are completed, the software determines whether the entire roll of webbing to be printed has been printed. If not, proceed to steps a)-f); if yes, end the printing process.

2. The method for inkjet printing webbing as described in claim 1, characterized in that, The measurement stage in step b) also includes obtaining the relationship curve between "jet density ink volume and ink stacking height", that is, obtaining the stacking height value of ink for a single print pass when the printhead jets ink volumes of different densities.

3. The method for inkjet printing webbing as described in claim 2, characterized in that, The method for obtaining the relationship curve between "spraying density ink volume and ink stacking height" is as follows: On a flat fixture, ink blocks of different densities are sprayed, and the height of the printed ink blocks is measured at 100%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, and 10% ink density. A line curve showing the relationship between spraying different ink densities and the height of the printed ink blocks is obtained. Then, the line curve is corrected using a Bezier curve to obtain a smooth curve showing the relationship between spraying density ink volume and ink stacking height.

4. The method for inkjet printing webbing as described in claim 3, characterized in that, The Bézier curve correction is performed using a recursive interpolation method.

5. The method for inkjet printing webbing as described in claim 4, characterized in that, The recursive interpolation includes an initial stage, first-order interpolation, second-order interpolation, and third-order interpolation.

6. The method for inkjet printing webbing as described in claim 1, characterized in that, The printing method for step c) the leveling stage is calculated by software: First, the number of scan print passes N required for the leveling stage is calculated, N = H MAX ÷ the ink stacking height per pass when spraying 100% density ink volume, where H MAX represents the height value of the lowest point on the webbing surface; then, the height data of different positions on the webbing surface measured and fed back by the 3D camera are divided by the number of print passes N to obtain the ink stacking height value required for a single print pass at different positions of the webbing; then, according to the relationship curve between "spray density ink volume and ink stacking height", the ink spray density ink volume corresponding to the ink stacking height value is obtained, and the ink spray density ink volume is used to control the ink spraying operation of different printhead nozzles at corresponding positions.

7. The method for inkjet printing webbing as described in claim 6, characterized in that, When filling the lowest point of the printed ribbon surface, all printheads spray ink simultaneously, i.e., spray 100% density ink volume; during the filling operation, no ink droplets are sprayed at the highest point of the ribbon surface.

8. The method for inkjet printing webbing as described in claim 1, characterized in that, In step c) the leveling stage, the printhead uses large ink droplets for ink ejection.

9. The method for inkjet printing webbing as described in claim 1, characterized in that, In step e) the image printing stage, the printhead can either eject ink droplets again during the return process to form the desired image, or it can not eject ink droplets during the return process, or it can use a micro-stepping printing method, that is, after the printhead module reaches one end of the crossbeam, it makes a small step perpendicular to the conveying direction and then performs scanning inkjet printing again.

10. The method for inkjet printing webbing as described in claim 1, characterized in that, In steps c) and e), during the inkjet process, the curing device is turned on to cure the ink below.

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