Paper tension and length adjusting system and method and printing device

Abstract

The invention discloses a paper tension and length adjusting system and method and a printing device, and relates to the technical field of printers. According to the invention, before the paper enters the printing area, in the printing process and after printing output, the input length and the output length of the paper and the position of the tensioning roller are cooperatively detected and controlled, so that the paper is always kept in a tensioned, flattened and length-controllable state in the printing area. When the paper feeding and discharging amount is consistent and the tensioning roller is located in the preset moving area, the system can operate stably and maintain constant tension. When the paper feeding and discharging amount difference occurs or the tensioning roller deviates from the preset moving area, the system can automatically adjust the tensioning force and coordinate the paper feeding and discharging actions according to the position and length difference value of the tensioning roller, so that the tensioning roller returns to the preset moving area, the paper length change is effectively compensated, the paper in the printing area is prevented from being loosened or excessively stretched, and the printing efficiency is improved. And the stability and the printing precision of the printing process are improved.

Description

Technical Field

[0001] This application relates to the field of printer technology, specifically to a paper tension and length adjustment system, method, and printing apparatus. Background Technology

[0002] With the development of digital printing, inkjet printing and continuous media printing technologies, printing equipment has placed higher demands on the flatness and tension stability of paper in the printing area. Especially in long-format or continuous printing scenarios, paper often undergoes slight expansion and contraction changes during the printing process due to changes in printing cycle, ink volume, or mechanical errors.

[0003] In existing technologies, common paper conveying systems often employ fixed tension structures or simple synchronous paper feeding and output control methods, lacking the ability to detect and adjust the paper input and output lengths in real time. When the paper length changes within the printing area, the paper feeding and output mechanisms cannot compensate in time, easily causing paper accumulation or tension in the printing area, which can lead to paper wrinkling, printed pattern deformation, or even equipment malfunction.

[0004] Furthermore, while some systems incorporate tension rollers or buffer structures, they fail to implement closed-loop control based on paper length variations. This results in lagging or uncontrollable tension adjustment, making it difficult to adapt to different printing conditions. The paper feed mechanism before printing and the paper output mechanism after printing typically operate independently, making it difficult to perceive the actual length changes and tension status of the paper within the printing area in real time. When the printing cycle changes or the paper undergoes slight deformation due to the printing process, the system cannot effectively compensate for differences in paper feed and output, easily causing paper tension fluctuations in the printing area, which can lead to problems such as registration errors, image stretching, or paper jams. Therefore, providing a paper tension and length adjustment system that integrates paper length detection, tension roller position detection, and tension adjustment is of great significance for improving the stability and print quality of printing equipment. Summary of the Invention

[0005] Based on this, a paper tension and length adjustment system, method, and printing device are provided to solve the technical problem that in existing continuous printing or long-format printing processes, the paper is prone to loosening, stretching, or wrinkling in the printing area due to asynchronous paper feed and output, uneven paper stress, or changes in paper length in the printing area, thereby affecting printing accuracy, image quality, and equipment operation stability.

[0006] On the one hand, a paper tension and length adjustment system is provided, the system including a source paper length detection device, a paper tension control device, a printing area adsorption device, an output paper length detection device, and a length controller; The source paper length detection device is used to feed paper into the paper tension control device and simultaneously detect the paper input length while feeding the paper. The paper tension control device is used to keep the paper taut and flat before it enters the printing area adsorption device to be adsorbed and printed. The printed paper is output from the printing area adsorption device to the output paper length detection device. The output paper length detection device is used to transport the printed paper and simultaneously detect the output paper length while transporting the printed paper. The paper tension control device includes a tension roller, a pressure regulating device, and a position detection device. The tension roller is located below the input end of the printing area adsorption device. The tension roller tensions and flattens the paper output from the source paper length detection device. The pressure regulating device is located on the side of the tension roller adjacent to the source paper length detection device to provide tension force. The position detection device is located below the tension roller and is suitable for detecting the position of the tension roller. The length controller is electrically connected to the pressure regulating device, the position detection device, the source paper length detection device, and the output paper length detection device; The length controller is used to control the pressure regulating device to provide a constant tension force to the tension roller and to control the source paper length detection device and the output paper length detection device to drive synchronously when the position detection device detects that the position of the tension roller is within a preset active area. The length controller is used to adjust the tension force provided by the pressure regulating device to increase or decrease according to the position of the tension roller and the difference between the paper input length and the paper output length when the position detection device detects that the position of the tension roller is outside the preset active area, and to control the source paper length detection device and the output paper length detection device to make the tension roller be within the preset active area.

[0007] In one embodiment, the pressure regulating device includes two pneumatic support structures, which are located at both ends of the tension roller.

[0008] In one embodiment, each of the pneumatic support structures includes a pressure valve and an air supply pipe, wherein the pressure valve controls the tension by adjusting the air pressure, and the air supply pipe is connected to an external air source.

[0009] In one embodiment, the position detection device includes two magnetic grids, each of which is located below the end of the tension roller, and the center point of the magnetic grid coincides with the center point of the preset active area.

[0010] In one embodiment, the source paper length detection device includes a first active conveying roller, a first driven conveying roller, a first driving device, and a first pressing control device. The first active conveying roller and the first driven conveying roller are arranged parallel to each other, and paper can be clamped and conveyed between the first active conveying roller and the first driven conveying roller. The first driving device is connected to the first active conveying roller, and the first pressing control device is connected to the first driven conveying roller. The first pressing control device controls whether the source paper length detection device conveys paper by controlling the first driven conveying roller to approach or move away from the first active conveying roller.

[0011] In one embodiment, the output paper length detection device includes a second active conveying roller, a second driven conveying roller, a second driving device, and a second pressing control device. The second active conveying roller and the second driven conveying roller are arranged parallel to each other, and the printed paper can be clamped and conveyed between the second active conveying roller and the second driven conveying roller. The second driving device is connected to the second active conveying roller, and the second pressing control device is connected to the second driven conveying roller. The second pressing control device controls whether the output paper length detection device conveys the printed paper by controlling the second driven conveying roller to approach or move away from the second active conveying roller.

[0012] In one embodiment, the system further includes an output guide roller located below the output end of the printing area adsorption device, which guides the printed paper into the output paper length detection device.

[0013] In one embodiment, the printing area adsorption device includes an input roller, an adsorption plate, and an output roller. The upper surfaces of the input roller, the adsorption plate, and the output roller are flush. The input roller constitutes the input end of the printing area adsorption device, and the output roller constitutes the output end of the printing area adsorption device. The upper surface of the adsorption plate is provided with a plurality of adsorption holes.

[0014] On the other hand, this application also provides a paper tension and length adjustment method for the paper tension and length adjustment system described above, the method comprising: The single printing time of the printing area adsorption device is obtained, and the source paper length detection device and the output paper length detection device are controlled to deliver paper according to the single printing time interval. The paper input length detected by the source paper length detection device and the paper output length detected by the output paper length detection device are obtained. A constant tension force is provided by a paper tension control device to tension and flatten the paper output from the source paper length detection device and send it into the printing area adsorption device for printing. During each print, the length controller is used to obtain the position of the tension roller detected by the position detection device, and it is determined whether the position of the tension roller is within the preset active area. When the position of the tension roller is within the preset active area, the pressure regulating device of the paper tension control device is controlled to provide a constant tension force to the tension roller and to control the source paper length detection device and the output paper length detection device to drive synchronously. When the position of the tension roller is outside the preset active area, the difference between the paper input length and the paper output length is obtained, and the relationship between the paper feed amount and the paper output amount is determined based on the position of the tension roller and the difference. When the amount of paper fed is greater than the amount of paper output, the source paper length detection device is stopped, and the pressure regulating device is reduced to reduce the tension. The output paper length detection device is then controlled to output the paper of the difference length until the tension roller is located at the center of the preset active area. After the tension roller is located at the center of the preset active area, the pressure regulating device is controlled to maintain a constant tension. When the paper feed is less than the paper output, the output paper length detection device is stopped, and the pressure regulating device is increased to simultaneously control the source paper length detection device to output paper of the difference length until the tension roller is located at the center of the preset active area. After the tension roller is located at the center of the preset active area, the pressure regulating device is controlled to maintain a constant tension.

[0015] Furthermore, this application also provides a printing apparatus that includes the paper tension and length adjustment system described above.

[0016] The aforementioned paper tension and length adjustment system, method, and printing device, by coordinating the detection and control of the paper's input length, output length, and tension roller position before, during, and after printing, ensure that the paper remains taut, flat, and of controllable length within the printing area. When the paper feed and output are consistent and the tension roller is within the preset active area, the system can operate stably and maintain constant tension. When there is a difference in paper feed or output or the tension roller deviates from the preset active area, the system can automatically adjust the tension force and coordinate the paper feed and output actions based on the tension roller position and length difference, bringing the tension roller back to the preset active area. This effectively compensates for changes in paper length, prevents paper slack or excessive stretching in the printing area, and improves the stability and accuracy of the printing process. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a front structural schematic diagram of a paper tension and length adjustment system in one embodiment of this application; Figure 2 This is a schematic diagram of the bottom structure of the paper tension and length adjustment system in one embodiment of this application; Figure 3 This is a schematic diagram of the paper tension control device in one embodiment of this application.

[0019] The markings in the diagram are as follows: The paper length detection device 1, first active conveyor roller 11, first driven conveyor roller 12, first drive device 13, first pressing control device 14, paper tension control device 2, tension roller 21, pressure regulating device 22, air pressure valve 221, air supply pipe 222, position detection device 23, printing area adsorption device 3, input roller 31, adsorption plate 32, output roller 33, output paper length detection device 4, second active conveyor roller 41, second driven conveyor roller 42, second drive device 43, first pressing control device 44, and output guide roller 5. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] Please see Figure 1 , Figure 2 , Figure 3This application provides a paper tension and length adjustment system, which includes a source paper length detection device 1, a paper tension control device 2, a printing area adsorption device 3, an output paper length detection device 4, and a length controller. The source paper length detection device 1 is used to feed paper into the paper tension control device 2 and simultaneously detect the paper input length during paper feeding. The paper tension control device 2 is used to keep the paper taut and flat before it enters the printing area adsorption device 3 to be adsorbed and printed. The printed paper is output from the printing area adsorption device 3 to the output paper length detection device 4. The output paper length detection device 4 is used to transport the printed paper and simultaneously detect the output paper length while transporting the printed paper. The paper tension control device 2 includes a tension roller 21, a pressure regulating device 22, and a position detection device 23. The tension roller 21 is located below the input end of the printing area adsorption device 3. The tension roller 21 tensions and flattens the paper output from the source paper length detection device 1. The pressure regulating device 22 is located on the side of the tension roller 21 adjacent to the source paper length detection device 1 to provide tension force. The position detection device 23 is located below the tension roller 21 and is suitable for detecting the position of the tension roller 21. The length controller is electrically connected to the pressure regulating device 22, the position detection device 23, the source paper length detection device 1, and the output paper length detection device 4; The length controller is used to control the pressure regulating device 22 to provide a constant tension force to the tension roller 21 and control the source paper length detection device 1 and the output paper length detection device 4 to drive synchronously when the position detection device 23 detects that the position of the tension roller 21 is within the preset active area. The length controller is used to adjust the tension force provided by the pressure regulating device 22 to increase or decrease, and control the source paper length detection device 1 and the output paper length detection device 4 to keep the tension roller 21 within the preset active area when the position detection device 23 detects that the position of the tension roller 21 is outside the preset active area, based on the position of the tension roller 21 and the difference between the paper input length and the paper output length.

[0023] Specifically, the length controller is used to obtain the difference between the paper input length and the paper output length when the position detection device 23 detects that the position of the tension roller 21 is outside the preset active area. Based on the position of the tension roller 21 and the difference, it determines the relationship between the paper feed amount and the paper output amount. When the paper feed amount is greater than the paper output amount, it controls the source paper length detection device 1 to stop and controls the pressure regulating device 22 to reduce the tension force, simultaneously controlling the output paper length detection device 4 to output paper of the difference length until the tension roller 21 is within the preset active area. When the tension roller 21 is located at the center of the preset active area, the pressure regulating device 22 is controlled to maintain a constant tension. When the paper feed is less than the paper output, the output paper length detection device 4 is controlled to stop, and the pressure regulating device 22 is controlled to increase the tension. The source paper length detection device 1 is simultaneously controlled to output the paper of the difference length until the tension roller 21 is located at the center of the preset active area. When the tension roller 21 is located at the center of the preset active area, the pressure regulating device 22 is controlled to maintain a constant tension.

[0024] The system incorporates a source paper length detection device 1, an output paper length detection device 4, and a length controller at the paper input and output ends, respectively. A paper tension control device 2, consisting of a tension roller 21, a pressure regulating device 22, a position detection device 23, and a length controller, is also installed at the input end of the printing area. This allows the system to acquire real-time data on the paper input length, output length, and the position of the tension roller 21 during printing. When the tension roller 21 is within a preset active area, the length controller maintains a constant tension force and synchronously drives the paper feeding and output devices to ensure stable printing. When the tension roller 21 deviates from the preset active area, the length controller dynamically adjusts the tension force based on the position of the tension roller 21 and the difference between the paper input and output lengths, coordinating the paper feeding and output actions to restore the tension roller 21 to the preset active area. This achieves closed-loop control of paper tension and length, improving the stability of the paper state in the printing area and printing accuracy.

[0025] In this embodiment, the pressure regulating device 22 includes two pneumatic support structures, which are located at both ends of the tension roller 21.

[0026] By setting pneumatic support structures at both ends of the tension roller 21, the force on both ends of the tension roller 21 is made more uniform, avoiding the problem of the tension roller 21 tilting or the paper being subjected to uneven force due to unilateral force application. This improves the stability and consistency of the paper tensioning process and further ensures that the paper remains flat in the printing area.

[0027] In this embodiment, each of the pneumatic support structures includes a pressure valve 221 and an air supply pipe 222. The pressure valve 221 controls the tension by adjusting the air pressure, and the air supply pipe 222 is connected to an external air source.

[0028] By installing a pneumatic valve 221 in the pneumatic support structure and connecting it to an external air source, the tension force can be continuously and controllably changed by adjusting the air pressure. Compared with mechanical springs and other methods, this method can adjust the tension force more precisely, improve the response speed and adjustment accuracy of tension control, and enhance the system's adaptability to different printing conditions.

[0029] In this embodiment, the position detection device 23 includes two magnetic grids, each of which is located below the end of the tension roller 21, and the center point of the magnetic grid coincides with the center point of the preset active area.

[0030] By setting magnetic gratings below both ends of the tension roller 21 and aligning the center point of the magnetic gratings with the center point of the preset active area, the position detection device 23 can accurately detect the displacement state of the tension roller 21 within the active area, thereby providing precise position feedback information to the length controller. This facilitates fine control of the position of the tension roller 21 and improves the reliability and stability of tension adjustment.

[0031] In this embodiment, the source paper length detection device 1 includes a first active conveying roller 11, a first driven conveying roller 12, a first driving device 13, and a first pressing control device 14. The first active conveying roller 11 and the first driven conveying roller 12 are arranged in parallel, and paper can be clamped and conveyed between the first active conveying roller 11 and the first driven conveying roller 12. The first driving device 13 is connected to the first active conveying roller 11, and the first pressing control device 14 is connected to the first driven conveying roller 12. The first pressing control device 14 controls whether the source paper length detection device 1 transmits paper by controlling the first driven conveying roller 12 to approach or move away from the first active conveying roller 11.

[0032] By setting a first active conveying roller 11, a first driven conveying roller 12, and a first pressing control device 14 in the source paper length detection device 1, the paper length can be detected while being clamped and conveyed. The start and stop control of paper conveying can be achieved by controlling the pressing state of the driven conveying roller, thereby accurately controlling the paper feed during tension adjustment and providing a reliable execution basis for paper length compensation.

[0033] In this embodiment, the output paper length detection device 4 includes a second active conveying roller 41, a second driven conveying roller 42, a second driving device 43, and a first pressing control device 14. The second active conveying roller 41 and the second driven conveying roller 42 are arranged in parallel, and the printed paper can be clamped and conveyed between the second active conveying roller 41 and the second driven conveying roller 42. The second driving device 43 is connected to the second active conveying roller 41, and the second pressing control device 44 is connected to the second driven conveying roller 42. The second pressing control device 44 controls whether the output paper length detection device 4 transmits the printed paper by controlling the second driven conveying roller 42 to approach or move away from the second active conveying roller 41.

[0034] By employing a structure similar to that of the source paper length detection device 1 in the output paper length detection device 4, stable clamping and conveying of the printed paper and length detection are achieved. The second pressing control device 44 controls the conveying state of the output paper, so that the output paper quantity can be coordinated with the paper feed quantity and the position adjustment process of the tension roller 21, ensuring the accuracy of the paper length compensation process.

[0035] In this embodiment, the system further includes an output guide roller 5, which is located below the output end of the printing area adsorption device 3. The output guide roller 5 guides the printed paper into the output paper length detection device 4.

[0036] By setting an output guide roller 5 below the output end of the printing area adsorption device 3, the printed paper can be smoothly guided into the output paper length detection device 4, reducing the risk of paper shifting, folding or sudden stress during the output process, and helping to maintain the continuity and stability of paper tension.

[0037] In this embodiment, the printing area adsorption device 3 includes an input roller 31, an adsorption plate 32, and an output roller 33. The upper surfaces of the input roller 31, the adsorption plate 32, and the output roller 33 are flush. The input roller 31 constitutes the input end of the printing area adsorption device 3, and the output roller 33 constitutes the output end of the printing area adsorption device 3. The upper surface of the adsorption plate 32 is provided with a plurality of adsorption holes.

[0038] By making the upper surfaces of the input roller 31, the adsorption plate 32 and the output roller 33 flush, and by setting multiple adsorption holes on the adsorption plate 32, the paper can be stably adsorbed and kept flat in the printing area, thereby reducing the floating or warping of the paper during the printing process and improving printing accuracy and image quality.

[0039] This application also provides a paper tension and length adjustment method for the paper tension and length adjustment system described above, the method comprising: The printing time of the printing area adsorption device 3 is obtained, and the paper is fed by the source paper length detection device 1 and the output paper length detection device 4 according to the single printing time interval. The paper input length detected by the source paper length detection device 1 and the paper output length detected by the output paper length detection device 4 are obtained. The paper is tensioned and flattened by a constant tension force provided by the paper tension control device 2 and fed into the printing area adsorption device 3 for printing. During each printing, the length controller obtains the position of the tension roller 21 detected by the position detection device 23, and determines whether the position of the tension roller 21 is within the preset active area. When the tension roller 21 is located within a preset active area, the pressure regulating device 22 of the paper tension control device 2 is controlled to provide a constant tension force to the tension roller 21 and to control the source paper length detection device 1 and the output paper length detection device 4 to drive synchronously. When the position of the tension roller 21 is outside the preset active area, the difference between the paper input length and the paper output length is obtained, and the relationship between the paper feed amount and the paper output amount is determined based on the position of the tension roller 21 and the difference. When the amount of paper fed is greater than the amount of paper output, the source paper length detection device 1 is stopped, and the pressure regulating device 22 is reduced to reduce the tension force. Simultaneously, the output paper length detection device 4 is controlled to output the paper of the difference length until the tension roller 21 is located at the center position of the preset active area. After the tension roller 21 is located at the center position of the preset active area, the pressure regulating device 22 is controlled to maintain a constant tension force. When the paper feed is less than the paper output, the output paper length detection device 4 is stopped, and the pressure regulating device 22 is increased to simultaneously control the source paper length detection device 1 to output the paper of the difference length until the tension roller 21 is located at the center of the preset active area. After the tension roller 21 is located at the center of the preset active area, the pressure regulating device 22 is controlled to maintain a constant tension.

[0040] By applying paper tension and length adjustment methods to the above system, and using the single printing time as the control cycle, combined with the position detection of the tension roller 21 and the judgment of the difference between the paper input and output lengths, dynamic and coordinated control of the paper feed, paper output, and tension is achieved. This enables the system to automatically compensate for changes in paper length during the printing process, keeping the tension roller 21 in the center of the preset active area, thereby improving the stability and continuity of the entire printing process.

[0041] Understandably, the position of the tension roller 21 detected by the position detection device 23 can be obtained by the length controller during each printing, instead of obtaining the position of the tension roller 21 detected by the position detection device 23 when each roll of printing paper is changed. That is, after the paper is changed and connected, it is determined whether the position of the tension roller 21 is within the preset active area, which can reduce the adjustment frequency.

[0042] This application also provides a printing apparatus that includes the paper tension and length adjustment system described above.

[0043] The aforementioned paper tension and length adjustment system, method, and printing device, by coordinating the detection and control of the paper's input length, output length, and tension roller position before, during, and after printing, ensure that the paper remains taut, flat, and of controllable length within the printing area. When the paper feed and output are consistent and the tension roller is within the preset active area, the system can operate stably and maintain constant tension. When there is a difference in paper feed or output or the tension roller deviates from the preset active area, the system can automatically adjust the tension force and coordinate the paper feed and output actions based on the tension roller position and length difference, bringing the tension roller back to the preset active area. This effectively compensates for changes in paper length, prevents paper slack or excessive stretching in the printing area, and improves the stability and accuracy of the printing process.

[0044] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A paper tension and length adjustment system, characterized in that, The system includes a source paper length detection device, a paper tension control device, a printing area adsorption device, an output paper length detection device, and a length controller. The source paper length detection device is used to feed paper into the paper tension control device and simultaneously detect the paper input length while feeding the paper. The paper tension control device is used to keep the paper taut and flat before it enters the printing area adsorption device to be adsorbed and printed. The printed paper is output from the printing area adsorption device to the output paper length detection device. The output paper length detection device is used to transport the printed paper and simultaneously detect the output paper length while transporting the printed paper. The paper tension control device includes a tension roller, a pressure regulating device, and a position detection device. The tension roller is located below the input end of the printing area adsorption device. The tension roller tensions and flattens the paper output from the source paper length detection device. The pressure regulating device is located on the side of the tension roller adjacent to the source paper length detection device to provide tension force. The position detection device is located below the tension roller and is suitable for detecting the position of the tension roller. The length controller is electrically connected to the pressure regulating device, the position detection device, the source paper length detection device, and the output paper length detection device; The length controller is used to control the pressure regulating device to provide a constant tension force to the tension roller and to control the source paper length detection device and the output paper length detection device to drive synchronously when the position detection device detects that the position of the tension roller is within a preset active area. The length controller is used to adjust the tension force provided by the pressure regulating device to increase or decrease according to the position of the tension roller and the difference between the paper input length and the paper output length when the position detection device detects that the position of the tension roller is outside the preset active area, and to control the source paper length detection device and the output paper length detection device to make the tension roller be within the preset active area.

2. The paper tension and length adjustment system as described in claim 1, characterized in that, The pressure regulating device includes two pneumatic support structures, which are located at both ends of the tensioning roller.

3. The paper tension and length adjustment system as described in claim 2, characterized in that, Each of the aforementioned pneumatic support structures includes a pressure valve and an air supply pipe. The pressure valve controls the tension by adjusting the air pressure, and the air supply pipe is connected to an external air source.

4. The paper tension and length adjustment system as described in claim 2, characterized in that, The position detection device includes two magnetic grids, each of which is located below the end of the tension roller, and the center point of the magnetic grid coincides with the center point of the preset active area.

5. The paper tension and length adjustment system as described in claim 1, characterized in that, The source paper length detection device includes a first active conveying roller, a first driven conveying roller, a first driving device, and a first pressing control device. The first active conveying roller and the first driven conveying roller are arranged in parallel, and paper can be clamped and conveyed between the first active conveying roller and the first driven conveying roller. The first driving device is connected to the first active conveying roller, and the first pressing control device is connected to the first driven conveying roller. The first pressing control device controls whether the source paper length detection device conveys paper by controlling the first driven conveying roller to approach or move away from the first active conveying roller.

6. The paper tension and length adjustment system as described in claim 1, characterized in that, The output paper length detection device includes a second active conveying roller, a second driven conveying roller, a second driving device, and a second pressing control device. The second active conveying roller and the second driven conveying roller are arranged in parallel, and the printed paper can be clamped and conveyed between the second active conveying roller and the second driven conveying roller. The second driving device is connected to the second active conveying roller, and the second pressing control device is connected to the second driven conveying roller. The second pressing control device controls whether the output paper length detection device conveys the printed paper by controlling the second driven conveying roller to approach or move away from the second active conveying roller.

7. The paper tension and length adjustment system as described in claim 1, characterized in that, The system also includes an output guide roller, which is located below the output end of the printing area adsorption device. The output guide roller guides the printed paper into the output paper length detection device.

8. The paper tension and length adjustment system as described in claim 1, characterized in that, The printing area adsorption device includes an input roller, an adsorption plate, and an output roller. The upper surfaces of the input roller, the adsorption plate, and the output roller are flush. The input roller constitutes the input end of the printing area adsorption device, and the output roller constitutes the output end of the printing area adsorption device. The upper surface of the adsorption plate is provided with multiple adsorption holes.

9. A method for adjusting paper tension and length, characterized in that, The method for the paper tension and length adjustment system according to any one of claims 1 to 8 comprises: The single printing time of the printing area adsorption device is obtained, and the source paper length detection device and the output paper length detection device are controlled to deliver paper according to the single printing time interval. The paper input length detected by the source paper length detection device and the paper output length detected by the output paper length detection device are obtained. A constant tension force is provided by a paper tension control device to tension and flatten the paper output from the source paper length detection device and send it into the printing area adsorption device for printing. During each print, the length controller is used to obtain the position of the tension roller detected by the position detection device, and it is determined whether the position of the tension roller is within the preset active area. When the position of the tension roller is within the preset active area, the pressure regulating device of the paper tension control device is controlled to provide a constant tension force to the tension roller and to control the source paper length detection device and the output paper length detection device to drive synchronously. When the position of the tension roller is outside the preset active area, the difference between the paper input length and the paper output length is obtained, and the relationship between the paper feed amount and the paper output amount is determined based on the position of the tension roller and the difference. When the amount of paper fed is greater than the amount of paper output, the source paper length detection device is stopped, and the pressure regulating device is reduced to reduce the tension. The output paper length detection device is then controlled to output the paper of the difference length until the tension roller is located at the center of the preset active area. After the tension roller is located at the center of the preset active area, the pressure regulating device is controlled to maintain a constant tension. When the paper feed is less than the paper output, the output paper length detection device is stopped, and the pressure regulating device is increased to simultaneously control the source paper length detection device to output paper of the difference length until the tension roller is located at the center of the preset active area. After the tension roller is located at the center of the preset active area, the pressure regulating device is controlled to maintain a constant tension.

10. A printing apparatus, characterized in that, Includes the paper tension and length adjustment system as described in any one of claims 1 to 8.

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