Double-sided printing apparatus

Abstract

The utility model belongs to the technical field of ink-jet printing, and particularly relates to double-sided printing equipment. The utility model relates to double-sided printing equipment, which comprises a shell, the first printing module is used for printing the first surface of the printing medium; the second printing module is used for printing the second surface of the printing medium; the paper overturning assembly is used for overturning the printing medium; the drying assembly comprises a first drying module and a second drying module; a conveying mechanism; the first printing module, the first drying module, the second drying module, the paper turning assembly and the second printing module are located in the shell. The first printing module and the second printing module are located on the two opposite sides of the paper turning assembly, and the drying assembly is located below the first printing module, the second printing module and the paper turning assembly and located between the first printing module and the second printing module. The double-sided printing device is compact in structure, can realize double-sided printing, and can conveniently observe and maintain the printing module.

Description

Technical Field

[0001] The utility model relates to the technical field of inkjet printing, in particular to a double-sided printing device. Background Art

[0002] In the printing industry, some products need to be printed on the front and back of the paper separately. In the prior art, the paper path layout and the surrounding printing module are often used to achieve flip printing. However, during the printing operation, the printing module often needs to be observed and maintained. The existing equipment often has problems such as inconvenient maintenance and insufficient operating space. Because the paper path layout and the surrounding printing module are used to achieve flipping, the paper has a certain shielding effect on the printing module, which affects observation and is not conducive to the observation and maintenance of the printing module. Utility Model Content

[0003] In view of this, the utility model provides a double-sided printing device, which is used to solve the technical problem that the existing double-sided printing device is not conducive to observing and maintaining the printing module.

[0004] The technical solution adopted by the utility model is:

[0005] In a first aspect, the utility model provides a double-sided printing device, comprising:

[0006] case;

[0007] A first printing module, used for printing on a first side of a printing medium;

[0008] A second printing module, used for printing on a second side of the printing medium, wherein the second side and the first side are two opposite sides of the printing medium;

[0009] A paper turning component, used for turning over the printing medium;

[0010] A drying assembly, comprising a first drying module and a second drying module;

[0011] A conveying mechanism, used for conveying printing media;

[0012] The first printing module, the first drying module, the second drying module, the paper turning assembly and the second printing module are located in the housing;

[0013] The first printing module and the second printing module are located on opposite sides of the paper turning assembly, and the drying assembly is located below the first printing module, the second printing module and the paper turning assembly, and between the first printing module and the second printing module;

[0014] The printing medium is transported by the transport mechanism and sequentially passes through the first printing module, the first drying module, the paper turning assembly, the second printing module and the second drying module.

[0015] Preferably, it also includes a first visual detection component, which is located on the side of the first drying module facing away from the second drying module. The first visual detection component is located on the printing medium conveying path between the first drying module and the paper turning component. The printing medium passes through the conveying mechanism to bypass the side of the first visual detection component facing away from the first drying module.

[0016] Preferably, after passing through the first visual detection component, the printing medium passes through the drying component from the middle of the drying component and is then transported to the position of the paper turning component.

[0017] Preferably, it also includes a second visual detection component, which is located on the side of the second drying module facing away from the first drying module, and the second visual detection component is located on the printing medium conveying path between the second drying module and the paper turning component. The printing medium passes through the conveying mechanism to bypass the side of the second visual detection component facing away from the second drying module.

[0018] Preferably, the paper turning device includes a first paper turning roller, a second paper turning roller, a first paper feeding roller and a second paper feeding roller, the first paper feeding roller and the second paper feeding roller are arranged in parallel, the first paper turning roller and the second paper turning roller are arranged at a right angle, the angle between the first paper turning roller and the first paper feeding roller is 45 degrees, and the angle between the second paper turning roller and the first paper feeding roller is 45 degrees.

[0019] Preferably, it also includes a skew adjustment component, which is used to adjust the movement trajectory of the printing medium. The skew adjustment component is located on the path of the printing medium before it passes through the first printing module.

[0020] Preferably, the first drying module comprises a first oven and a second oven which are symmetrically arranged, the printing medium passes through the first oven along a first direction and then turns back to a second direction and passes through the second oven along the second direction, and the second direction and the first direction are opposite directions.

[0021] Preferably, the second drying module comprises a third oven and a fourth oven which are symmetrically arranged, and the printing medium passes through the third oven along the third direction and then turns back to the fourth direction and passes through the fourth oven along the fourth direction, and the fourth direction and the third direction are opposite directions.

[0022] Preferably, the conveying mechanism includes a first power assembly, a second power assembly and a third power assembly, the first power assembly is located on the printing medium conveying path before the first printing module, the second power assembly is located on the printing medium conveying path between the paper turning assembly and the second printing module, and the third power assembly is located on the printing medium conveying path after the second drying module.

[0023] Preferably, it also includes a first tension detection member and a second tension detection member, the first tension detection member is located on the print medium conveying path between the first power assembly and the first printing module, the second tension detection member is located on the print medium conveying path between the second power assembly and the second printing module, the first tension detection member is used to detect the tension of the print medium before entering the first printing module, and the second tension detection member is used to detect the tension of the print medium before entering the second printing module.

[0024] Beneficial effects: The double-sided printing device of the utility model has the paper turning component built into the printing device, the first printing module and the second printing module are respectively arranged on both sides of the paper turning component, and the drying component is arranged below and located between the first printing module and the second printing module. In this way, the front sides of the first printing module and the second printing module can face the position not blocked by the paper turning component and the drying component. Therefore, it can realize the timely drying of the back side of the printing medium and the printing medium, and facilitate the observation and maintenance of the printing module. At the same time, it also makes the internal layout of the printing device more compact, effectively reduces the length of the equipment, and significantly reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the embodiment of the utility model, the drawings required for use in the embodiment of the utility model will be briefly introduced below. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work, and these are all within the protection scope of the utility model.

[0026] Figure 1 It is a schematic diagram of the layout of the main components of the double-sided printing device of the utility model;

[0027] Figure 2 It is a structural schematic diagram of a double-sided printing device of the utility model;

[0028] Figure 3 This is a structural view of the drying component in the utility model;

[0029] Figure 4 It is a structural schematic diagram of the paper turning device in the utility model.

[0030] Parts and their numbers in the figure:

[0031] The first power component 1, the first tension detection component 2, the first visual detection component 3, the skew adjustment component 4, the first printing module 5, the paper turning component 6, the first paper turning roller 61, the second paper turning roller 62, the first paper feeding roller 63, the second paper feeding roller 64, the second power component 7, the second tension detection component 8, the second printing module 9, the second visual detection component 10, the third power component 11, the first drying module 12, the first oven 121, the second oven 122, the second drying module 13, the third oven 131, the fourth oven 132, and the shell 14. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the description of the utility model, it should be understood that the orientation or position relationship indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the utility model. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "includes..." do not exclude the presence of other identical elements in the process, method, article or device including the elements. If there is no conflict, the embodiments of the utility model and the various features in the embodiments can be combined with each other, all within the scope of protection of the utility model.

[0033] Example 1

[0034] like Figure 1 As shown, the utility model provides a double-sided printing device. The double-sided printing device of this embodiment includes a housing 14, a first printing module 5, a second printing module 9, a paper turning component 6, a drying component and a conveying mechanism.

[0035] The first printing module 5 is used to print on the first side of the printing medium, and the second printing module 9 is used to print on the second side of the printing medium. The second side and the first side are two opposite sides of the printing medium, that is, one of the first side and the second side is the front side of the printing medium, and the other is the back side of the printing medium. In this embodiment, the first printing module 5 and the second printing module 9 are used to print on the front side and the back side of the printing medium respectively, thereby realizing double-sided printing of the product.

[0036] The paper turning component 6 is used to turn over the printing medium; after the printing medium passes through the first printing module 5 to complete the printing of the first side, it is turned 180 degrees by the paper turning component 6, and after the second side is turned over to an angle facing the second printing module 9, it is transported to the position where the second printing module 9 is located to print the second side.

[0037] The drying component includes a first drying module 12 and a second drying module 13. The utility model uses the drying module to dry the printed medium after printing. When double-sided printing is adopted, the first drying module 12 can be used to dry the printed medium whose first side is printed by the first printing module, and then the second drying module 13 can be used to dry the printed medium whose second side is printed by the second printing module.

[0038] The conveying mechanism is used to convey the printing medium so that it moves along a predetermined path, so that the printing medium passes through each link of the printing device in a set order, thereby completing the entire printing process;

[0039] In this embodiment, the print medium is transported by the transport mechanism and sequentially passes through the first print module 5, the first drying module 12, the paper turning assembly 6, the second print module 9 and the second drying module 13. The transport mechanism includes a plurality of transport rollers arranged along the transport path of the print medium.

[0040] The printing medium is first transported by the conveying mechanism through the first printing module 5 for printing on the first side, and then enters the first drying module 12 for drying. The dried printing medium continues to be transported to the paper turning component 6, and after being flipped by the paper turning component 6, it is transported to the second printing module 9 for printing on the second side. After the second side is printed, it is transported to the second drying module 13 for drying.

[0041] In this embodiment, the first printing module 5, the first drying module 12, the second drying module 13, the paper turning assembly 6 and the second printing module 9 are located in the housing 14; the first printing module 5 and the second printing module 9 are located on opposite sides of the paper turning assembly 6, and the drying assembly is located below the first printing module 5, the second printing module 9 and the paper turning assembly 6;

[0042] In this embodiment, the paper turning component 6 is built into the printing device through the aforementioned layout structure. The first printing module 5 and the second printing module 9 are respectively arranged on both sides of the paper turning component 6, and the drying component is arranged below and located between the first printing module 5 and the second printing module 9. In this way, the front direction of the first printing module 5 and the second printing module 9 is not blocked by the paper turning component 6 and the drying component. Therefore, it is possible to realize the turning over of the printing medium and the timely drying of the printing medium, and it is convenient to observe and maintain the printing module. At the same time, it also makes the internal layout of the printing device more compact, effectively reduces the length of the equipment, and significantly reduces the cost.

[0043] like Figure 2 As shown, this embodiment also includes a first visual detection component 3, which is located on the side of the first drying module 12 facing away from the second drying module 13, and the first visual detection component 3 is located on the printing medium conveying path between the first drying module 12 and the paper turning component 6, and the printing medium passes through the conveying mechanism to bypass the side of the first visual detection component 3 facing away from the first drying module 12.

[0044] The first visual inspection component 3 is used for inspection after the first side of the print medium is printed. After the first side of the print medium is printed, the print medium is transported by the transport mechanism to the first drying module 12 for drying. The dried print medium is inspected by the first visual inspection component 3. After the inspection by the first visual inspection component 3 is completed, the print medium is transported to the paper turning component 6 for turning. Since the first visual inspection component 3 is facing away from the first drying module 12, the visual inspection process is not easily disturbed by the drying component.

[0045] In this embodiment, after the printing medium passes through the first visual detection component 3, it passes through the drying component from the middle of the drying component and is then transported to the position of the paper turning component 6. In this embodiment, the gap between the first drying module 12 and the second drying module 13 in the drying component is used to provide a path for the printing medium to be transported, so that the printing medium can be transported to the position of the paper turning component 6 without blocking the printing module.

[0046] The printing device of this embodiment also includes a second visual detection component 10, which is located on the side of the second drying module 13 facing away from the first drying module 12. The second visual detection component 10 is located on the printing medium conveying path between the second drying module 13 and the paper turning component 6. The printing medium passes through the conveying mechanism to bypass the side of the second visual detection component 10 facing away from the second drying module 13.

[0047] The second visual inspection component 10 is used for inspection after the second side of the printing medium is printed. Under the conveying mechanism, the printing medium is put into the second drying module 13 for drying after the second side is printed. The dried printing medium is inspected by the second visual inspection component 10. After the second visual inspection component 10 is inspected, the printing medium is transported around the second drying module 13 to the top of the gap between the first drying module 12 and the third drying module 13, and then passes through the gap between the first drying module 12 and the third drying module 13 from top to bottom, and then is transported to the subsequent unit from the bottom of the drying component to the right. Since the second visual inspection component 10 is facing away from the side of the second drying module 13, the visual inspection process is not easily disturbed by the drying component.

[0048] The printing device of this embodiment further includes a skew adjustment component 4 , which is used to adjust the movement trajectory of the printing medium. The skew adjustment component 4 is located on the path of the printing medium before it passes through the first printing module 5 .

[0049] The skew adjustment component 4 is used to fine-tune the movement trajectory of the printing medium. Before the printing medium is conveyed to the first printing module 5, it first passes through the skew adjustment component 4, and then enters the first printing module 5 for printing after fine-tuning by the skew adjustment component 4. This can reduce the fluctuation of the paper during its operation before entering the printing process, making the paper's running trajectory more stable.

[0050] like Figure 3 As shown, in this embodiment, the first drying module 12 includes a first oven 121 and a second oven 122 that are symmetrically arranged. The printing medium passes through the first oven 121 along a first direction and then turns back to a second direction, and passes through the second oven 122 along the second direction. The second direction and the first direction are opposite directions.

[0051] The above method can reverse the paper path in the first drying module 12, thereby increasing the drying time of the printing medium in the first drying module 12, so that the printing medium meets the drying time requirement and ensures that the printing surface does not pass through the paper roller before drying, thereby ensuring the printing effect.

[0052] like Figure 3 As shown, in this embodiment, the second drying module 13 includes a third oven 131 and a fourth oven 132 that are symmetrically arranged. The printing medium passes through the third oven 131 along the third direction and then turns back to the fourth direction, and passes through the fourth oven 132 along the fourth direction. The fourth direction and the third direction are two opposite directions.

[0053] The above method can reverse the paper path in the second drying module 13, thereby increasing the drying time of the printing medium in the second drying module 13, so that the printing medium meets the drying time requirement and ensures that the printing surface does not pass through the paper roller before drying, thereby ensuring the printing quality.

[0054] like Figure 2 As shown, in this embodiment, the conveying mechanism includes a first power assembly 1, a second power assembly 7 and a third power assembly 11. The first power assembly 1 is located on the printing medium conveying path before the first printing module 5, the second power assembly 7 is located on the printing medium conveying path between the paper turning assembly 6 and the second printing module 9, and the third power assembly 11 is located on the printing medium conveying path after the second drying module 13.

[0055] The first power assembly 1 is located on the printing medium conveying path before the first printing module 5, which means that the printing medium first passes through the first power assembly 1 and then passes through the first printing module 5. In this embodiment, the printing medium is pulled by the first power assembly 1 and then conveyed to the first printing module located on the left side of the printing device for printing.

[0056] The second power assembly 7 adjusts the tension of the printing medium in the section before printing the second side, so as to stabilize the tension and improve the quality of printing on the second side. The second power assembly 7 is used to control the paper tension between the first power assembly 1 and the second power assembly 7, and transmit it to the second printing module 9 downstream of the paper.

[0057] The third power assembly 11 is used to control the paper tension between the second power assembly 7 and the third power assembly 11, and transport it to the next unit; under the traction of the third power assembly 11, the printing medium passes through the drying assembly and then goes out from the lower right side of the printing device.

[0058] The printing device of this embodiment also includes a first tension detection member 2 and a second tension detection member 8. The first tension detection member 2 is located on the printing medium conveying path between the first power component 1 and the first printing module 5, that is, the printing medium passes through the first power component 1, the first tension detection member 2 and the first printing module 5 in sequence.

[0059] The second tension detecting member 8 is located on the printing medium conveying path between the second power assembly 7 and the second printing module 9, that is, the printing medium passes through the second power assembly 7, the second tension detecting member 8 and the second printing module 9 in sequence.

[0060] The first tension detecting member 2 is used to detect the tension of the printing medium before it enters the first printing module 5 , and the second tension detecting member 8 is used to detect the tension of the printing medium before it enters the second printing module 9 .

[0061] This embodiment uses the first tension detection member 2 and the second tension detection member 8 to detect the tension of the printing medium during transportation, so that each power component can adjust the tension according to the detection result, so that the printing medium can maintain a stable tension during transportation, thereby ensuring the printing quality. The first tension detection member 2 detects the paper path tension between the first power component 1 and the first printing module 5, and feeds back to the second power component 7 for tension control;

[0062] The second tension detection member 8 is used to detect the paper path tension between the second power assembly 7 and the second printing module 9, and feed it back to the third power assembly 11 for tension control.

[0063] like Figure 4 As shown, in this embodiment, the paper turning device includes a first paper turning roller 61, a second paper turning roller 62, a first paper feeding roller 63 and a second paper feeding roller 64, the first paper feeding roller 63 and the second paper feeding roller 64 are arranged in parallel, the first paper turning roller 61 and the second paper turning roller 62 are arranged at a right angle, the angle between the first paper turning roller 61 and the first paper feeding roller 63 is 45 degrees, and the angle between the second paper turning roller 62 and the first paper feeding roller 63 is 45 degrees.

[0064] The printing medium paper enters the assembly with the front side facing upward, and is turned 45° by the first paper turning roller 61, at which time the back side of the paper faces upward and moves toward the operation surface, and then turns 180° after passing the first paper passing roller 63 and the second paper passing roller 64, with the front side of the paper facing upward and moving toward the transmission surface, and finally turns 45° by the second paper turning roller 62, with the back side of the paper facing upward and moving in the original direction. The above-mentioned paper turning device is not only compact in structure, but also can keep the original moving direction unchanged before and after the printing medium is turned over.

[0065] The specific process of printing using the double-sided printing device of this embodiment is as follows:

[0066] After being pulled by the first power component 1, the print medium is transported to the first printing module 5 on the left side of the device for printing. Before the print medium enters the first printing module 5, the first tension detection component 2 detects the tension of the print medium in this section and feeds back to the second power component 7 downstream of the first printing module 5. The second power component 7 adjusts the tension of the print medium in this section to stabilize the tension.

[0067] Before entering the front printing module, the tilt adjustment component 4 performs a second fine adjustment on the running track of the printing medium to reduce the fluctuation of the printing medium during its running before entering the printing.

[0068] After the front printing is completed, the print medium passes through the paper roller and enters the first drying module 12 in the lower middle of the device for drying. Due to the drying time requirements of the print medium and the fact that the printed surface cannot pass through the paper roller before drying, the first drying module 12 is provided with two sets of symmetrical ovens to reverse the paper path once and prolong the drying time of the print medium in the oven.

[0069] After the front side is dried, the print medium passes through the paper roller and the first visual inspection component 3 for inspection after the front side printing is completed, then goes around the first drying module 12 back to the middle of the device and moves upward, and enters the paper turning component 6 arranged at the upper part of the device to turn the print medium over so that the back side of the print medium faces upward.

[0070] After the printing medium is turned over, it is pulled and transported to the second printing module on the right side of the device for printing by the second power component 7. Before the printing medium enters the reverse printing module, the second tension detection component 8 detects the tension of the printing medium in this section and feeds back to the third power component 11 downstream of the second printing module. The third power component 11 adjusts the tension of the printing medium in this section to stabilize the tension.

[0071] After the reverse printing is completed, the print medium passes through the paper roller and enters the second drying module 13 in the lower middle of the device for drying. Similarly, the second drying module 13 is provided with two sets of symmetrical ovens, so that the paper path is reversed once, thereby lengthening the drying time of the print medium in the oven.

[0072] After the back side is dried, the print medium passes through the second visual inspection component 10 through the paper roller for inspection after the back side printing is completed, and then passes through the third power component 11 and several paper rollers to make the print medium move around the second drying module 13 and finally walk out from the lower right side of the device.

[0073] The above is only a specific implementation of the present invention. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention.

[0074] The above is only a specific implementation of the present invention. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention.

Claims

1. A double-sided printing device, characterized in that: include: case; A first printing module, used for printing on a first side of a printing medium; A second printing module, used for printing on a second side of the printing medium, wherein the second side and the first side are two opposite sides of the printing medium; A paper turning component, used for turning over the printing medium; A drying assembly, comprising a first drying module and a second drying module; A conveying mechanism, used for conveying printing media; The first printing module, the first drying module, the second drying module, the paper turning assembly and the second printing module are located in the housing; The first printing module and the second printing module are located on opposite sides of the paper turning assembly, and the drying assembly is located below the first printing module, the second printing module and the paper turning assembly, and between the first printing module and the second printing module; The printing medium is transported by the transport mechanism and sequentially passes through the first printing module, the first drying module, the paper turning assembly, the second printing module and the second drying module.

2. The double-sided printing device according to claim 1, characterized in that: It also includes a first visual detection component, which is located on the side of the first drying module facing away from the second drying module. The first visual detection component is located on the printing medium conveying path between the first drying module and the paper turning component. The printing medium passes through the conveying mechanism to bypass the side of the first visual detection component facing away from the first drying module.

3. The double-sided printing device according to claim 2, characterized in that: After passing through the first visual detection component, the printing medium passes through the drying component from the middle of the drying component and is then transported to the position of the paper turning component.

4. The double-sided printing device according to claim 1, characterized in that: It also includes a second visual detection component, which is located on the side of the second drying module facing away from the first drying module. The second visual detection component is located on the printing medium conveying path between the second drying module and the paper turning component. The printing medium passes through the conveying mechanism and bypasses to the side of the second visual detection component facing away from the second drying module.

5. The double-sided printing device according to claim 1, characterized in that: The paper turning assembly includes a first paper turning roller, a second paper turning roller, a first paper feeding roller and a second paper feeding roller. The first paper feeding roller and the second paper feeding roller are arranged in parallel. The first paper turning roller and the second paper turning roller are arranged at a right angle. The angle between the first paper turning roller and the first paper feeding roller is 45 degrees, and the angle between the second paper turning roller and the first paper feeding roller is 45 degrees.

6. The double-sided printing device according to claim 1, characterized in that: It also includes a skew adjustment component, which is used to adjust the movement trajectory of the printing medium. The skew adjustment component is located on the path of the printing medium before it passes through the first printing module.

7. The double-sided printing device according to claim 1, characterized in that: The first drying module includes a first oven and a second oven that are symmetrically arranged. The printing medium passes through the first oven along a first direction and then turns back to a second direction and passes through the second oven along the second direction. The second direction and the first direction are opposite directions.

8. The double-sided printing device according to claim 1, characterized in that: The second drying module includes a third oven and a fourth oven that are symmetrically arranged. The printing medium passes through the third oven along the third direction and then turns back to the fourth direction and passes through the fourth oven along the fourth direction. The fourth direction and the third direction are opposite directions.

9. The double-sided printing device according to any one of claims 1 to 8, characterized in that: The conveying mechanism includes a first power assembly, a second power assembly and a third power assembly. The first power assembly is located on the printing medium conveying path before the first printing module, the second power assembly is located on the printing medium conveying path between the paper turning assembly and the second printing module, and the third power assembly is located on the printing medium conveying path after the second drying module.

10. The double-sided printing device according to claim 9, characterized in that: It also includes a first tension detection member and a second tension detection member, the first tension detection member is located on the print medium conveying path between the first power assembly and the first printing module, the second tension detection member is located on the print medium conveying path between the second power assembly and the second printing module, the first tension detection member is used to detect the tension of the print medium before it enters the first printing module, and the second tension detection member is used to detect the tension of the print medium before it enters the second printing module.

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