A double-sided inkjet device

Abstract

This invention relates to the field of inkjet printing technology and provides a double-sided inkjet device, comprising: an unwinding mechanism, a feed roller assembly, a front-side printing mechanism, a first drying and cooling mechanism, a back-side printing mechanism, a second drying and cooling mechanism, and a rewinding mechanism; the unwinding mechanism is used to unwind paper, and the rewinding mechanism is used to rewind paper; the feed roller assembly drives the paper from the unwinding mechanism to the rewinding mechanism, and the front-side printing mechanism, the first drying and cooling mechanism, the back-side printing mechanism, and the second drying and cooling mechanism are arranged sequentially along the direction of paper movement; the front-side printing mechanism is used to spray ink on the front side of the paper; the first and second drying and cooling mechanisms are used to dry and cool the ink on the front and back sides of the paper, respectively; the back-side printing mechanism is used to spray ink on the back side of the paper; and the second drying and cooling mechanism is used to spray ink on the back side of the paper. This solution can effectively improve printing speed.

Description

Technical Field

[0001] This invention relates to the field of inkjet printing technology, and more particularly to a double-sided inkjet device. Background Technology

[0002] Printing is an ancient technology, but it is constantly being updated. With the continuous development of printing technology, inkjet-based digital printing systems have become very popular and have gained widespread social recognition.

[0003] Existing digital inkjet printing devices have small print widths and slow printing speeds, which do not meet the requirements for industrial-grade digital inkjet printing production.

[0004] Therefore, there is a need to provide a double-sided inkjet device that can effectively improve printing speed and width.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The main purpose of this invention is to overcome the problems of small printing width and slow printing speed of digital inkjet printers, and to provide a double-sided inkjet printer that can effectively improve printing speed and width, produce good printing results, have high resolution, and prevent a white line from affecting the printing effect.

[0007] To achieve the above objectives, the first aspect of the present invention provides a double-sided inkjet device, comprising: an unwinding mechanism, a feed roller assembly, a front-side printing mechanism, a first drying and water-cooling mechanism, a back-side printing mechanism, a second drying and water-cooling mechanism, and a rewinding mechanism.

[0008] The unwinding mechanism is used to unwind the paper, and the rewinding mechanism is used to rewind the paper.

[0009] One end of the feeding roller assembly is an unwinding mechanism, and the other end is a winding mechanism. The feeding roller assembly drives the paper from the unwinding mechanism to the winding mechanism. Along the direction of paper movement, a front printing mechanism, a first drying and water cooling mechanism, a back printing mechanism, and a second drying and water cooling mechanism are arranged in sequence.

[0010] The front printing mechanism is used to spray ink onto the front side of the paper;

[0011] The first drying and cooling mechanism is used to dry and cool the ink on the front side of the paper.

[0012] The back-side printing mechanism is used to spray ink onto the back of the paper;

[0013] The second drying and cooling mechanism is used to dry and cool the ink on the back of the paper.

[0014] According to an exemplary embodiment of the present invention, the double-sided inkjet device further includes a splitting blade disposed between the second drying and cooling mechanism and the winding mechanism for cutting paper, wherein the length direction of the splitting blade is the same as the paper movement direction.

[0015] According to an exemplary embodiment of the present invention, the feed roller assembly sequentially includes a first segmented roller assembly, a second segmented roller assembly, a third segmented roller assembly, a fourth segmented roller assembly, a fifth segmented roller assembly, and a sixth segmented roller assembly along the direction of paper movement;

[0016] The first segment roller assembly is positioned between the unwinding mechanism and the front printing mechanism for tensioning and / or correcting paper deviation.

[0017] The second segment roller assembly is positioned below the front printing mechanism, so that the front side of the paper located in the second segment roller assembly faces upward;

[0018] The third segment roller assembly is located at the first drying and cooling mechanism. The third segment roller assembly moves the front side of the paper to face down, so that the front side of the paper faces down when it is located at the first drying and cooling mechanism.

[0019] The fourth segment roller assembly is located between the first drying and cooling mechanism and the back printing mechanism for tensioning and / or correcting paper deviation.

[0020] The fifth segment roller assembly is located below the rear printing mechanism;

[0021] The sixth segment roller assembly is located at the second drying and cooling mechanism. The sixth segment roller assembly moves the back of the paper to face down, so that the back of the paper faces down when it is located at the second drying and cooling mechanism.

[0022] According to an exemplary embodiment of the present invention, the front printing mechanism includes one or more printing components, each printing component including an ink pump, a print head, and a control unit;

[0023] The ink tank is connected to the printhead and is used to supply ink;

[0024] The printhead includes an ignition mechanism and M inkjet channels; each inkjet channel includes two or more rows of nozzles that are staggered with each other; the ignition mechanism and the nozzles of the inkjet channels are connected to control the ink droplets from the nozzles; the M inkjet channels are arranged along the direction of paper movement, and the length direction of the inkjet channels is perpendicular to the direction of paper movement; M is a natural number greater than or equal to 2.

[0025] The control unit is communicatively connected to the printhead and is used to control the printhead to ignite and drip ink droplets onto the paper. The control unit instructs the printhead to ignite the nozzles of M inkjet channels simultaneously at first specified time intervals. Each time a nozzle is ignited, a maximum of one ink droplet is dripped. The distance between any two adjacent inkjet channels is M × N times the unit dot pitch. A total of N ignitions are performed. The distance between ink droplets dripping along the paper's movement direction between two adjacent ignitions in each inkjet channel is M times the unit dot pitch. N ignitions constitute one group, with a second specified time interval between each group of ignitions. Multiple groups of ignitions are repeated until printing is complete. The ratio of the second specified time to the first specified time is M-1:M; N is a natural number greater than or equal to 2.

[0026] As an example embodiment of the present invention, the resolution of the printed product along the paper movement direction is N times that of 12.5 dpi.

[0027] According to an exemplary embodiment of the present invention, when the resolution of the printed product along the direction of paper movement is 600 dpi and M is 4, the speed of the paper movement is 130-162 meters per minute.

[0028] Preferably, when the resolution of the printed product along the paper movement direction is 600 dpi and M is 4, the maximum speed of the paper movement is 160 m / min at an ignition frequency of 21 kHz.

[0029] As an example embodiment of the present invention, the unit dot distance is the distance between two adjacent pixels of the printed product.

[0030] According to an exemplary embodiment of the present invention, the number of nozzles in each column is greater than or equal to 400; the length of the inkjet channel is consistent with the printing width of the paper.

[0031] According to an exemplary embodiment of the present invention, the width of the paper is 700-900mm; the diameter of the unwinding mechanism that rolls up all the paper is 1-1.2m; and the diameter of the winding mechanism that rolls up all the paper is 1-1.2m.

[0032] According to an exemplary embodiment of the present invention, each printing component prints one color, and the pattern colors of the M inkjet channels of each printing component are consistent.

[0033] According to an exemplary embodiment of the present invention, the ink in the ink tank includes: UV ink and / or pigment ink and / or dye ink.

[0034] According to an exemplary embodiment of the present invention, the front printing mechanism and the back printing mechanism have the same structure.

[0035] The advantages of this invention are as follows: This solution designs a high-speed, large-format double-sided inkjet device for paper, enabling continuous printing with a maximum width of 900mm. It can perform in-line center cutting, centrally cutting the paper into two equal smaller rolls. The roller feeding solves the problem of manual feeding difficulties. Adjustable hot air drying and water-cooled roller devices address printing drying and paper edge curling issues. M inkjet channels are set up, each group igniting N times. After one group is completed, the step size between two groups is adjusted before ignition, ensuring that the M groups of ignitions cover the entire printed image. The paper movement speed is increased, achieving a high-frequency effect with a low-frequency ignition frequency, reducing printhead costs, mitigating defects caused by nozzle clogging, and increasing printing speed by M-1 times. The maximum speed at 600dpi resolution is 162 meters per minute. Simultaneously, the M inkjet channels prevent white lines from affecting the printing effect, resulting in excellent print quality. Attached Figure Description

[0036] The above and other objects, features, and advantages of this application will become more apparent from the detailed description of exemplary embodiments with reference to the accompanying drawings. The drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0037] Figure 1 A schematic diagram of a double-sided inkjet device is shown.

[0038] Figure 2 The illustration shows the printing effect of a single pass.

[0039] Figure 3 The illustration shows the printing effect of a row of nozzles arranged side by side.

[0040] Figure 4 The illustration shows a printing effect with a row of nozzles arranged side by side and the nozzles clogged.

[0041] Figure 5 A schematic diagram of the M-row nozzles of the printhead is shown.

[0042] Figure 6 A schematic diagram of the printhead structure (excluding ink channels) is shown.

[0043] Figure 7 A schematic diagram of the printhead structure (including ink channels) is shown.

[0044] Figure 8 The diagram illustrates the steps of a rapid printing method using an inkjet printer.

[0045] Figure 9 A schematic diagram of multicolor printhead printing is shown.

[0046] Figure 10 The illustration shows a diagram of a fast inkjet printer printing.

[0047] Figure 11 The illustration shows a comparison of inkjet printing effects.

[0048] Among them, 1—unwinding mechanism, 2—feeding roller assembly, 3—front printing mechanism, 4—first drying and water cooling mechanism, 5—back printing mechanism, 6—second drying and water cooling mechanism, 7—center splitter, 8—winding mechanism, and 9—paper. Detailed Implementation

[0049] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0050] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0051] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0052] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0053] It should be understood that although the terms first, second, third, etc., may be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Therefore, the first component discussed below may be referred to as the second component without departing from the teachings of this application. As used herein, the term "and / or" includes all combinations of any one and more of the associated listed items.

[0054] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing this application, and therefore cannot be used to limit the scope of protection of this application.

[0055] According to a first specific embodiment of the present invention, the present invention provides a double-sided inkjet device, such as... Figure 1 As shown, it includes: an unwinding mechanism 1, a feeding roller assembly 2, a front printing mechanism 3, a first drying and water cooling mechanism 4, a back printing mechanism 5, a second drying and water cooling mechanism 6, a center splitter 7, and a winding mechanism 8.

[0056] The width of paper 9 is 700-900mm.

[0057] The unwinding mechanism 1 is used to unwind the paper 9. The diameter of the unwinding mechanism 1, which winds up all the paper 9, is 1-1.2m, including the rolled-up paper 9.

[0058] The winding mechanism 8 is used to wind up the paper 9. The diameter of the winding mechanism that winds up all the paper is 1-1.2m, including the rolled-up paper 9.

[0059] One end of the feed roller assembly 2 is the unwinding mechanism 1, and the other end is the winding mechanism 8. The feed roller assembly 2 drives the paper 9 from the unwinding mechanism 1 to the winding mechanism 8. Along the direction of the paper 9's movement, the front printing mechanism 3, the first drying and cooling mechanism 4, the back printing mechanism 5, the second drying and cooling mechanism 6, and the center splitter 7 are arranged in sequence. The feed roller assembly 2 drives the paper 9 to move at a uniform speed. The speed of the paper 9 is M-1 times the speed of the paper 9 using a single inkjet channel, where M is the number of inkjet channels, thus solving the problem of difficulty in manual paper feeding.

[0060] The feed roller assembly 2, along the direction of paper 9 movement, sequentially includes a first segmented roller assembly, a second segmented roller assembly, a third segmented roller assembly, a fourth segmented roller assembly, a fifth segmented roller assembly, a sixth segmented roller assembly, and a seventh segmented roller assembly. The first segmented roller assembly is positioned between the unwinding mechanism 1 and the front-side printing mechanism 3, and is used for tensioning and / or correcting the paper 9. For example... Figure 1As shown, the first segmented roller assembly includes a tensioning component, a correction component, and a traction component. The tensioning component is located at the front end of the first segmented roller assembly and is used to tension the paper. At this time, the paper 9 moves horizontally, and tension is achieved by the vertically staggered rollers. The correction component is located downstream of the tensioning component, at which time the paper 9 moves vertically downwards. Figure 1 The paper path correction component is located on the right side of the paper 9. It uses sensors to check the position of the paper 9 and, based on the skewing of the paper edge, twists it in the opposite direction to straighten the paper path. A traction component drives the movement of the paper 9. The first segmented roller assembly has a traction component, and traction components can also be added to other segmented roller assemblies as needed. The traction component includes a large roller and a small roller. The paper 9 is located between the large roller and the small roller. The small roller is a pressure roller, and the large roller is a drive roller. The pressure roller presses the paper 9 onto the drive roller, and the drive roller provides driving force, pulling the paper 9 forward. The second segmented roller assembly is located below the front printing mechanism 3, ensuring that the front side of the paper 9 is facing upwards when located in the second segmented roller assembly. The third segmented roller assembly is located at the first drying and cooling mechanism 4. The third segmented roller assembly moves the front side of the paper 9 downwards, ensuring that the front side of the paper 9 is facing downwards when located at the first drying and cooling mechanism 4. Preferably, the first drying and cooling mechanism 4 includes a dryer and a water cooler, with the dryer located below the paper 9 and the water cooler located above the paper 9, with the paper 9 positioned between the dryer and the water cooler. The dryer uses airflow provided by a fan, which is accelerated through a narrow slit and then blown onto the paper. Because the airflow is heated, heat is carried away by the water-cooling rollers to prevent excessive temperature rise and deformation. A fourth segmented roller assembly is positioned between the first drying and cooling mechanism 4 and the back-side printing mechanism 5, used for tensioning and / or correcting the paper 9. A fifth segmented roller assembly is positioned below the back-side printing mechanism 5. A sixth segmented roller assembly is positioned at the second drying and cooling mechanism 6, moving the back side of the paper 9 downwards, ensuring that the back side of the paper 9 faces downwards when located at the second drying and cooling mechanism 6. Preferably, the second drying and cooling mechanism 4 includes a dryer and a water cooler, with the dryer located below the paper 9 and the water cooler located above the paper 9, with the paper 9 positioned between the dryer and the water cooler. The seventh segment roller assembly is located between the second drying and cooling mechanism 6 and the winding mechanism 8.

[0061] The front printing mechanism 3 is used for inkjet printing on the front side of the paper 9. The front printing mechanism 3 includes one or more printing components, each printing component printing one color.

[0062] The setup of the printing assembly and the printing method using it are improvements upon single-pass printing. Single-pass (also called 1-pass or single-pass) printing involves arranging printheads in a row, keeping them stationary, while the paper moves rapidly beneath the printheads. Each nozzle in the printhead ejects ink droplets at a fixed frequency, and these droplets form a line on the paper. Multiple nozzles arranged in this way create many parallel lines on the paper, and these dense lines form a square. For example... Figure 2 As shown, some areas of the square are inked while others are not, forming the printed pattern. Clearly, to maintain the same ink density across a line of prints, the higher the ink jet frequency, the faster the paper moves. The printing speed is determined by the ignition frequency, which is the ink jet frequency of the printhead; a higher ignition frequency results in a faster printing speed. However, high-ignition-frequency printheads are often more expensive and difficult to maintain. Current technology uses a row of nozzles arranged side-by-side, each with its own independently controlled ignition time, to print a complete pattern, such as... Figure 3 As shown. Current printing speed relies entirely on the firing frequency, and there's limited room for improvement in firing frequency. Furthermore, if a nozzle becomes clogged, a white line will appear, such as... Figure 4 As shown, this results in poor printing quality and a high probability of nozzle clogging. Therefore, to further improve printing speed and quality, M inkjet channels are used for alternating printing.

[0063] Specifically, each printing component includes: an ink tank, a printhead, and a control unit.

[0064] The resolution of the printed product along the direction of paper movement 9 is N times 12.5 dpi, where N is a natural number greater than or equal to 2. When the resolution of the printed product along the direction of paper movement 9 is 600 dpi and M is 4, the paper movement speed is 130-162 m / min. Preferably, when the resolution of the printed product along the direction of paper movement 9 is 600 dpi and M is 4, if the ignition frequency is 21 kHz, the maximum paper movement speed is 160 m / min.

[0065] The ink tank connects to the printhead and is used to supply ink. The ink in the ink tank includes: UV ink and / or pigment ink and / or dye ink.

[0066] The printhead includes an ignition mechanism and M inkjet channels. Each inkjet channel includes two or more rows of nozzles that are staggered. The ignition mechanism is connected to the nozzles of the inkjet channels to control the ink droplets. The M inkjet channels are arranged along the direction of paper movement, with the length of the inkjet channels perpendicular to the direction of paper movement. M is a natural number greater than or equal to 2; N is a natural number greater than or equal to 2. The printhead also includes M ink channels, which connect the ink tank and the inkjet channels. Each ink channel connects to K rows of staggered nozzles, where K is the number of rows of nozzles in each inkjet channel. Each row of nozzles connected to each ink channel is located in a different inkjet channel. The ink color is consistent across all inkjet channels.

[0067] The control unit is communicatively connected to the printhead and is used to control the printhead ignition and the dropping of ink droplets onto the paper. The control unit instructs the printhead to simultaneously ignite the nozzles of M inkjet channels at first specified time intervals. Each ignition of one nozzle produces a maximum of one ink droplet. The distance between any two adjacent inkjet channels is M × N times the unit dot pitch. A total of N ignitions are performed. For each inkjet channel, the distance between ink droplets dropped along the paper's movement direction (i.e., the length direction of the paper) between two adjacent ignitions is M times the unit dot pitch. N ignitions constitute one group. A second specified time interval is observed between each group of ignitions. Multiple groups of ignitions are repeated until printing is complete. The ratio of the second specified time interval to the first specified time interval is M-1:M. In a preferred embodiment, the control unit controls the printhead to repeat M groups of ignitions N times.

[0068] The unit dot pitch is the distance between two adjacent pixels in the printed product. Each ink droplet corresponds to one pixel.

[0069] In a preferred embodiment, the spacing between two adjacent inkjet channels is 180-200 pixels, preferably 192 pixels, and the number of nozzles in each column is greater than or equal to 400, preferably 400. The spacing between two adjacent columns of nozzles is 20-30 pixels, preferably 24 pixels. The width of the paper 9 is 700-900mm, and the length of the inkjet channel is consistent with the printing width of the paper. Generally, the length of the inkjet channel is slightly narrower than the width of the paper 9, leaving some margin.

[0070] Staggered rows of nozzles can improve the resolution along the length of the inkjet channel. The interval between adjacent nozzles in each row is K-1 pixels, where K is the number of nozzle rows per inkjet channel, and K is a natural number greater than or equal to 2. Preferably, there are 4 inkjet channels, each with 2 nozzle rows, the distance between two adjacent inkjet channels is 8.128 mm, and the distance between two adjacent rows of nozzles is 1.016 mm.

[0071] Specifically, such as Figure 5 , Figure 6 and Figure 7As shown, M inkjet channels are located at the bottom of the printhead, used to spray ink onto the paper 9 below the printhead. The distance between any two rows of adjacent inkjet channels is a specified distance, which is N×M unit dot pitch. Unit dot pitch is the distance between two pixels in the printed product. Each inkjet channel has at least 800 nozzles, and the distance between ink droplets printed from each channel across the width of the paper 9 is one unit dot pitch. Each inkjet channel includes two staggered rows of nozzles, with at least 400 nozzles in each row. Adjacent nozzles in each row are spaced 2 unit dot pitches apart. By using this staggered arrangement, the actual printing effect is the same as having multiple nozzles per row with each two nozzles spaced one unit dot pitch apart; it can be considered that each row has at least 800 nozzles.

[0072] Figure 5 In this paper, M is 4, the distance between two adjacent inkjet channels is 8.128mm (i.e., the distance of 192 pixels, or 192 / 600 inches), the distance between two adjacent columns of nozzles in each inkjet channel is 1.016mm (i.e., the distance of 24 pixels), the distance between two adjacent nozzles in each column is 0.085mm (i.e., the distance of 2 pixels), there are 400 nozzles in each column, and the distance between two adjacent columns of nozzles with the same serial number is 0.042mm (i.e., the distance of 1 pixel) in the width direction of the paper 9. Figure 5 There are a total of 8 rows of nozzles, such as Figure 6 As shown, from right to left, columns A, B, C, D, E, F, G, and H are arranged in an alternating pattern to improve inkjet resolution. Figure 7 As shown, there are four ink channels. From right to left, the first connects to columns B and G, the second to columns A and H, the third to columns C and F, and the fourth to columns D and E. All four ink channels are the same color, ensuring that the ink in all M inkjet channels is the same color. Connecting non-adjacent columns with ink channels is to eliminate the effects of static electricity.

[0073] The control unit instructs the printhead to simultaneously ignite the nozzles of M inkjet channels at first specified time intervals. Each ignition of a nozzle produces a maximum of one ink droplet, and each ink droplet corresponds to one pixel. Pixels that do not need to be printed do not receive ink drops. There is an interval of M-1 pixels between every two rows of ink droplets (ink droplets from the same inkjet channel dropped in two consecutive ignitions). That is, the distance between ink droplets dropped in two consecutive ignitions is M times the unit dot pitch. A total of N ignitions are performed, forming one group. There is a second specified time interval between each group of ignitions. Multiple groups of ignitions are repeated until printing is complete. The ratio of the second specified time interval to the first specified time interval is M-1:M.

[0074] Use printing components for fast printing, such as Figure 8 As shown, it includes the following steps:

[0075] S1: Paper 9 continues to move along the length of paper 9.

[0076] Paper 9 moves on the digital printing press. An encoder on the press moves with the position of paper 9. The control board determines the current position of the paper and whether ignition is needed based on the scale on the encoder. Using this method, the speed of paper 9 can be increased by (M-1) times. Assuming the inkjet resolution along the direction of paper 9 is 600 dpi, the printhead ignition frequency is 21 kHz, and there are four ink channels, then according to the traditional dot-matrix inkjet method, the maximum speed of paper 9 is 21000 / 600×25.4=889mm / s, which is 53.3 meters / minute. However, using this method, the printing speed can be increased by 3 times, or 160 meters / minute.

[0077] M inkjet channels are set along the direction of paper movement 9. The interval between two adjacent inkjet channels is M×N times the unit dot pitch. The unit dot pitch is the distance between two pixels in the printed product; M is a natural number greater than or equal to 2; N is a natural number greater than or equal to 2.

[0078] The distance between any two adjacent inkjet channels is a specified distance, which is N×M unit dot pitch. Each inkjet channel consists of two rows of staggered nozzles, with each row containing more than or equal to 400 nozzles.

[0079] The ink in all M inkjet channels is the same color.

[0080] Preferably, M is 4, N is 48, and the unit dot pitch is 1 / 600 inch.

[0081] S2: At a first specified time interval, the nozzles of M inkjet channels are ignited simultaneously. Each time a nozzle is ignited, it can drop a maximum of one ink droplet. Each ink droplet corresponds to one pixel. The distance between the ink droplets dropped between two ignitions is M times the unit dot distance. A total of N ignitions are performed.

[0082] No ink droplets drip from pixels that do not need to be printed.

[0083] The number of ignitions is determined by the unit dot pitch and the distance between two adjacent inkjet channels. N is an integer multiple of 2, the resolution in the paper movement direction is N×12.5 dpi, and the unit dot pitch is 1 / (N×12.5) inch.

[0084] Preferably, since the ink sprayed by the nozzle of the first inkjet channel during the Nth ignition overlaps with that of subsequent nozzles, in order to reduce repeated ink spraying, the nozzle of the first inkjet channel does not need to drip ink droplets during the Nth ignition.

[0085] S3: Pause ignition for a second specified time, the ratio of the second specified time to the first specified time is M-1:M;

[0086] S4: Repeat steps S2 and S3 until printing is complete.

[0087] Repeat steps S2 and S3 a total of M times.

[0088] The advantages of the inkjet printer's fast printing method are illustrated below through detailed examples.

[0089] Figure 9 The diagram illustrates a multi-color printhead. A multi-color printhead consists of multiple rows of nozzles arranged side-by-side. Each row of nozzles is designed to spray a different color of ink, typically CMYK four-color ink. Figure 9 From left to right, the four colors are CMYK. As the paper moves, droplets of the four colors are sprayed onto the same spot, creating multiple colors due to different combinations of inks, thus achieving color printing.

[0090] The basic idea of ​​this solution is to have multiple inkjet nozzles spray the same color, but with staggered ink dots, so that the ink does not print in the same position. The four types of nozzles print different rows, which overlap and complement each other. Different nozzles do not print on the same pixel, forming a complete image. In fact, each inkjet channel mentioned here includes two rows of nozzles that are staggered (e.g., ...). Figure 5 and Figure 6 As shown), they are very close together to improve horizontal resolution. For ease of description, we will still say there are a total of 4 inkjet channels.

[0091] like Figure 10 As shown, for the Epson i3200 printhead, taking 600 dpi as an example, the dot pitch is measured in units of 1 / 600 inch (the distance between ink droplets). The printhead has a total of 4 inkjet channels, as follows: Figure 5 As shown, the distance between two adjacent inkjet channels is 192 dot pitch. First, confirm that M is 4 and N is 48.

[0092] If each nozzle sprays three pixels apart, the inkjet channel printing resolution becomes 150 dpi, and the paper movement speed can be increased to three times the original. Each row of nozzles ignites simultaneously. After 48 ignitions, on the 49th ignition, the paper has moved 48 * 4 = 192 dot pitches. This means that the position of the paper facing the nozzle orifice of the second inkjet channel coincides with the position facing the first row of nozzles during the first ignition. This results in multiple ink sprays at the same location, while adjacent areas appear blank. Figure 10As shown in the two diagrams above, the paper 9 moves from right to left, and the nozzles of the four inkjet channels ignite simultaneously. After a period of time, the nozzle of the second inkjet channel will spray ink at the same location where the first inkjet channel nozzle finishes spraying ink. The ink spraying positions will overlap, and there will be gaps between the two ink droplets.

[0093] To avoid this phenomenon, the proposed method is as follows: After 48 ignitions at a spacing of 4 dots (unit dot spacing), the next ignition is performed one-quarter of the way ahead, which is 3 dots (unit dot spacing), thus shifting the ink droplets that would otherwise overlap by one unit dot spacing. This process is repeated 48 times at a spacing of 4 dots (unit dot spacing), followed by one ignition at a spacing of 3 dots (unit dot spacing), and so on. Figure 10 As shown, Figure 10 In the third image, if the nozzle of the second inkjet channel (from the left) fires at time intervals corresponding to four dot spacings after 48 firings, the ink droplets ejected by the second inkjet channel nozzle will overlap with those ejected by the first inkjet channel nozzle. To avoid overlap, there are three blank dots between every two adjacent ink droplets. If the nozzle fires at an interval corresponding to one unit dot spacing, it will drop onto one of these blank dots, filling in the gaps in the inkjet image. After 48 firings, if the nozzle fires again at 48 firings at three dot spacings earlier... Figure 10 As shown in the fourth image, the inkjet prints are staggered and then supplement each other, increasing the print resolution from 150 dpi to 600 dpi. This means that at a first specified time interval, all four rows of nozzles are ignited simultaneously. Each nozzle produces a maximum of one ink droplet per ignition, with each droplet corresponding to one pixel. Pixels that don't need to be printed don't drip ink. There's a 3-pixel interval between every two rows of droplets, for a total of N ignitions, where N is 48. Each group consists of N ignitions. The ignition pauses for a second specified time, with the ratio of the second specified time to the first specified time being M-1:M. After printing one group, there's a second specified time pause before printing the next group. The interval between every two groups is the second specified time, and this cycle repeats. Because the printing distance only increases by a factor of 3 during the frequency conversion switch (i.e., the pause for the second specified time), the final speed is the lowest speed in the entire process, so the paper movement speed is increased by a factor of 3.

[0094] As can be seen from the above scheme, the ignition frequency remains unchanged, but the speed of paper 9 increases threefold. This scheme uses a low-frequency ignition frequency to print a high-frequency ink droplet density. The more inkjet channels there are, the faster the paper moves; the paper speed is M-1 times that of row-by-row printing. Furthermore, because the same column of ink droplets (ink droplets along the direction of paper 9's movement) is alternately ejected from four inkjet channels, if one nozzle becomes clogged, it will not completely block the entire column of ink droplets. Figure 4Instead of the usual phenomenon of ink droplets clogging the nozzle, it only clogs a quarter (1 / M) of a column of ink dots, which significantly improves the nozzle clogging situation. For example... Figure 11 As shown, Figure 11 The inkjet effect comparison image shows the complete inkjet pattern at the top and the inkjet situation after one nozzle is blocked at the bottom, where only a quarter of the ink droplets are not produced.

[0095] The relationship between inkjet nozzles and ignition is shown in Table 1. The first row of nozzles corresponds to the nozzles of the first inkjet channel, the second row of nozzles corresponds to the nozzles of the second inkjet channel, the third row of nozzles corresponds to the nozzles of the third inkjet channel, and the fourth row of nozzles corresponds to the nozzles of the fourth inkjet channel.

[0096] Table 1

[0097]

[0098]

[0099]

[0100]

[0101] Analysis of Table 1 shows that:

[0102] (1) The first group of ignitions was performed 48 times, with the first row of nozzles spraying ink from the 3rd point to the 191st point every 4 units of dot spacing. The second group of ignitions was performed 48 times, then ink was sprayed one unit of dot spacing forward. The first row of nozzles sprayed ink from the 194th point to the 382nd point every 4 units of dot spacing, and the second row of nozzles sprayed ink from the 2nd point to the 190th point every 4 units of dot spacing. The third group of ignitions was performed 48 times, then ink was sprayed one unit of dot spacing forward again. The first row of nozzles sprayed ink from the 385th point to the 573rd point every 4 units of dot spacing, and the second row of nozzles sprayed ink from the 193rd point every 4 units of dot spacing. At the 381st dot, the third row of nozzles sprays ink from the 1st dot to the 189th dot every 4 units of dot spacing. The fourth group fires 48 times, then sprays ink from the next unit of dot spacing. The first row of nozzles sprays ink from the 576th dot to the 764th dot every 4 units of dot spacing; the second row sprays ink from the 384th dot to the 572nd dot every 4 units of dot spacing; the third row sprays ink from the 192nd dot to the 380th dot every 4 units of dot spacing; the fourth row sprays ink from the 0th dot to the 188th dot every 4 units of dot spacing; and so on. By supplementing the preceding pixels with each subsequent row of nozzles, the paper speed is increased by 3 times while maintaining the same printing resolution.

[0103] (2) The position switching point is an integer multiple of 48 ignition times. As long as the first row of nozzles does not spray during this ignition, all positions will be sprayed once without repeated ink spraying, thus spraying out the whole image completely.

[0104] (3) Similarly, if the distance between two adjacent rows of nozzles is determined to be 8.128mm, the number of ink droplets between two adjacent rows of nozzles at 25dpi is: 8.128 / 25.4*25=8. The resolution corresponding to this invention is an integer multiple of 25, and the number of ink droplets between two rows of nozzles is also an integer multiple of 8. At this time, M equals 4, N equals 2, and the resolution of the printed product along the paper movement direction is N times 12.5dpi. That is, a new printing mode can be rearranged according to this mode. If the new resolution is more than 25 dpi, for example, 600 dpi is 24 times 25 dpi, then N = 24 * 2 = 48. Following the pattern of printing once every M pixels, every N prints, 4×N rows of dots are printed. The printing positions are then changed at intervals, changing position 4 to position 3. This process is repeated for 4×N rows of dots, then position 3 is changed to position 2. This process is repeated for 4×N rows of dots, then position 2 is changed to position 1. After the position change, the first pixel of the first row of nozzles is not printed, or the last pixel before the position change is not printed. This ensures that the image is printed perfectly without any omissions or duplicates.

[0105] (4) As can be seen from the above analysis, the principle of this scheme is based on the two ink droplet intervals and then adjusting the time interval between each two groups to replenish ink droplets in a staggered manner. As long as the interval between two adjacent inkjet channels is M×N times the unit dot distance and the distance between the ink droplets dropped by each two ignitions is M times the unit dot distance, the paper 9 movement speed can be increased to nearly M-1 times while the printing resolution remains unchanged.

[0106] One printing component can print one color. If you need to print a colored pattern, you can set up several printing components to print multiple colors respectively.

[0107] The back-side printing mechanism 5 is used to spray ink onto the back of the paper 9. The structure of the back-side printing mechanism 5 is the same as that of the front-side printing mechanism 3, and the printing method is also the same. It is only necessary to change the paper 9 from face-up to back-side-up.

[0108] The first drying and cooling mechanism 4 is used to dry and cool the ink on the front side of the paper 9. The second drying and cooling mechanism 6 is used to dry and cool the ink on the back side of the paper 9. The first drying and cooling mechanism 4 and the second drying and cooling mechanism 6 have the same structure, realizing adjustable hot air drying and cooling in inkjet printing. It can meet the drying requirements at high speed while achieving energy saving and environmental protection. The cooling of the paper after drying ensures that the paper 9 will not lose too much water and deform in subsequent production.

[0109] The center-splitting blade 7 is used to cut the paper 9. The length direction of the blade of the center-splitting blade 7 is the same as the direction of movement of the paper 9. The center-splitting blade is located in the middle of the width direction of the paper 9 and is used to cut the paper 9 in the middle.

[0110] The winding mechanism 8 winds up either the entire roll or two smaller rolls.

[0111] Existing technologies use more expensive printheads to achieve large-format printing, often doubling the number of printheads to increase printing speed. This solution designs a high-speed, large-format, double-sided inkjet printer for paper, using inexpensive printheads to achieve continuous, high-speed printing without increasing the number of printheads. The maximum width is 900mm, and it can perform in-line center cutting, centrally cutting the paper into two equal smaller rolls. Roller feeding solves the problem of manual feeding difficulties. Adjustable hot air drying and water-cooled roller devices address printing drying and paper edge curling issues. M inkjet channels are set up, each group igniting N times. After one group is completed, the step size between two groups is adjusted before ignition, ensuring that the M groups of ignitions cover the entire printed area. The increased paper movement speed and the use of low-frequency ignition to output high-frequency effects reduce printhead costs, mitigate defects caused by nozzle clogging, and increase printing speed by M-1 times, achieving a maximum speed of 162 meters per minute at 600 dpi resolution. Furthermore, the M inkjet channels prevent white lines from affecting print quality, resulting in excellent print quality. The drying and cooling mechanism enables high-speed drying while achieving energy conservation and environmental protection. Cooling the dried paper ensures it doesn't lose too much moisture or deform during subsequent production. The center slitting blade 7 can be connected to cut a large sheet into two smaller sheets to meet different subsequent processing requirements. The winding structure can wind up one large sheet or two small sheet sheets.

[0112] Exemplary embodiments of the present invention have been specifically shown and described above. It should be understood that the present invention is not limited to the detailed structures, arrangements, or implementations described herein; rather, the present invention is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A double-sided inkjet device, characterized in that, include: The unwinding mechanism, the feeding roller assembly, the front printing mechanism, the first drying and water cooling mechanism, the back printing mechanism, the second drying and water cooling mechanism, and the rewinding mechanism; The unwinding mechanism is used to unwind the paper, and the rewinding mechanism is used to rewind the paper. One end of the feeding roller assembly is an unwinding mechanism, and the other end is a winding mechanism. The feeding roller assembly drives the paper from the unwinding mechanism to the winding mechanism. Along the direction of paper movement, a front printing mechanism, a first drying and water cooling mechanism, a back printing mechanism, and a second drying and water cooling mechanism are arranged in sequence. The front printing mechanism is used to spray ink onto the front side of the paper; The first drying and cooling mechanism is used to dry and cool the ink on the front side of the paper. The back-side printing mechanism is used to spray ink onto the back of the paper; The second drying and cooling unit is used to dry and cool the ink on the back of the paper. The front printing mechanism includes one or more printing components, each printing component including an ink tank, a print head, and a control unit; The ink tank is connected to the printhead and is used to supply ink; The printhead includes an ignition mechanism and M inkjet channels; each inkjet channel includes two or more rows of nozzles that are staggered with each other; the ignition mechanism and the nozzles of the inkjet channels are connected to control the ink droplets from the nozzles; the M inkjet channels are arranged along the direction of paper movement, and the length direction of the inkjet channels is perpendicular to the direction of paper movement; M is a natural number greater than or equal to 2. The control unit is communicatively connected to the printhead and is used to control the printhead to ignite and drip ink droplets onto the paper. The control unit instructs the printhead to simultaneously ignite the nozzles of M inkjet channels at first specified intervals. Each ignition of one nozzle produces a maximum of one ink droplet. The distance between any two adjacent inkjet channels is M × N times the unit dot pitch. A total of N ignitions are performed. The distance between ink droplets dripping along the paper's movement direction between two adjacent ignitions in each inkjet channel is M times the unit dot pitch. N ignitions constitute one group. A second specified interval is paused between each group of ignitions. Multiple groups of ignitions are repeated until printing is complete. The ratio of the second specified interval to the first specified interval is M-1:M; N is a natural number greater than or equal to 2.

2. The double-sided inkjet device according to claim 1, characterized in that, It also includes a splitting blade located between the second drying and cooling mechanism and the winding mechanism, used for cutting paper, with the length direction of the splitting blade being the same as the direction of paper movement.

3. The double-sided inkjet device according to claim 1, characterized in that, The feed roller assembly includes, in sequence along the direction of paper movement, a first segmented roller assembly, a second segmented roller assembly, a third segmented roller assembly, a fourth segmented roller assembly, a fifth segmented roller assembly, and a sixth segmented roller assembly; The first segment roller assembly is positioned between the unwinding mechanism and the front printing mechanism for tensioning and / or correcting paper deviation. The second segment roller assembly is positioned below the front printing mechanism, so that the front side of the paper located in the second segment roller assembly faces upward; The third segment roller assembly is located at the first drying and cooling mechanism. The third segment roller assembly moves the front side of the paper to face down, so that the front side of the paper faces down when it is located at the first drying and cooling mechanism. The fourth segment roller assembly is located between the first drying and cooling mechanism and the back printing mechanism for tensioning and / or correcting paper deviation. The fifth segment roller assembly is located below the rear printing mechanism; The sixth segment roller assembly is located at the second drying and cooling mechanism. The sixth segment roller assembly moves the back of the paper to face down, so that the back of the paper faces down when it is located at the second drying and cooling mechanism.

4. The double-sided inkjet device according to claim 1, characterized in that, When the resolution of the printed product along the paper movement direction is 600 dpi and M is 4, the paper movement speed is 130-162 meters per minute.

5. The double-sided inkjet device according to claim 4, characterized in that, The number of nozzles in each column is greater than or equal to 400; the length of the inkjet channel is the same as the printing width of the paper.

6. The double-sided inkjet device according to claim 1, characterized in that, The width of the paper is 700-900mm; the diameter of the unwinding mechanism that rolls up all the paper is 1-1.2m; the diameter of the winding mechanism that rolls up all the paper is 1-1.2m.

7. The double-sided inkjet device according to claim 1, characterized in that, Each printing component prints one color, and the ink color is consistent across the M inkjet channels of each printing component.

8. The double-sided inkjet device according to claim 1, characterized in that, The ink in the ink tank includes: UV ink and / or pigment ink and / or dye ink.

9. The double-sided inkjet device according to claim 1, characterized in that, The front printing mechanism and the back printing mechanism have the same structure.

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