Self-drying downward-returning type single-jet-printing-module sheet-fed digital ink-jet printer

Abstract

The utility model discloses a self-drying downward-returning type single jet printing module sheet-fed digital ink-jet printer which comprises a paper feeding conveying belt, a jet printing cylinder is arranged on the downstream of the paper feeding conveying belt, a jet printing module is arranged above the jet printing cylinder, and a traction chain is arranged below the jet printing cylinder in a matched mode. An air suction shaping belt is arranged below the advancing section of the traction chain, a drying channel for printing paper to pass through is formed between the advancing section of the traction chain and the advancing section of the air suction shaping belt, and a drying mechanism is arranged above the drying channel; a paper returning output position and a paper collecting output position are arranged on a conveying path of the traction chain, and a paper returning mechanism is arranged between the paper returning output position of the traction chain and the input end of the paper feeding conveying belt. The double-sided jet printing machine is ingenious in structural design, only one set of jet printing module needs to be arranged on the whole machine, single-sided printing operation of a single piece of paper can be achieved, double-sided printing operation can also be achieved, the printing face of the paper can be effectively dried and is not prone to wrinkling, and the double-sided jet printing machine is particularly suitable for the high-quality printing requirement of high-end products.

Description

Technical Field

[0001] The utility model relates to the technical field of inkjet printing equipment, in particular to a self-drying bottom-returning single-jet printing module single-sheet digital inkjet printer. Background Art

[0002] Sheet-fed digital inkjet printing machinery can achieve high-precision printing on both sides of a single sheet of paper, and has the advantages of plateless printing, on-demand printing, high speed and high quality.

[0003] In order to achieve high-precision printing, sheet-fed digital inkjet printers usually use rollers with paper gripping mechanisms to perform precise paper transfer operations. Among them, in the model that uses two sets of printing modules to achieve double-sided printing of a single sheet of paper, printing modules are respectively arranged above the front printing roller and the back printing roller. When the paper passes under the first printing module with the front printing roller, the first printing module realizes the printing operation on the front side of the paper. The paper that has completed the front printing is transferred from the paper transfer roller to the back printing roller. When the paper passes under the second printing module with the back printing roller, the second printing module realizes the printing operation on the back side of the paper. Because this model uses two sets of printing modules, its equipment manufacturing cost is relatively high and the investment is relatively large.

[0004] In addition, due to structural design limitations, single-sheet digital inkjet printers that use roller paper feeding usually cannot be equipped with a drying mechanism, or can only be equipped with a drying mechanism on the outside of the printing roller to improve the drying degree of the printed surface. However, due to the high speed of the roller, the effective drying time of this drying method is very short, and the ink drying effect on the printed surface of the paper is not ideal. The ink on the paper that has been printed on the front side is not fully dried and is immediately transferred to the next roller. In this way, after the printed surface of the paper is attached to the surface of the roller, it is easy for the ink to migrate and cause the image and text to be blurred, which seriously affects the quality of inkjet printing. Some companies also use a paper feed belt to transfer the paper that has been printed on the front side, and set a drying mechanism on the paper feed belt transmission path to dry the printed surface. Although this method can effectively extend the drying time, the paper will produce wrinkles after absorbing ink and being dried. On the one hand, the paper wrinkles are easy to cause paper jams on the paper feed belt, which seriously affects the stability of paper transmission and production efficiency; on the other hand, the paper wrinkles will also affect the printing accuracy and quality when printing on the reverse side.

[0005] Secondly, paper, as a printing medium, usually has residual paper dust on the surface of the paper and residual paper fibers on the edge of the paper. When the paper reaches the bottom of the inkjet head for inkjet printing, the airflow will drive the paper dust on the surface of the paper or the paper fibers on the edge of the paper to fly up, which can easily cause the inkjet head to be blocked by paper dust, which will seriously affect the quality of the printed product or affect the printing efficiency due to shutdown for maintenance. Currently, in single-sheet digital inkjet printers that use rollers to transfer paper, because single sheets of paper need to be transferred accurately, due to the constraints of small structural design space and immature technology, there is no mechanism for online cleaning of paper dust and paper fibers, which cannot meet the high-efficiency and high-quality printing needs of high-end customers.

[0006] Furthermore, in order to improve printing quality and image quality, some high-quality papers need to be coated with a layer of a specific medium (coating liquid) before inkjet printing to improve the ink absorption rate. At present, in the field of sheet-fed inkjet printing, this coating process needs to be carried out using a separate device, which not only has low work efficiency, but also requires a lot of equipment investment and high production costs. Utility Model Content

[0007] In order to overcome the above shortcomings, the technical problem to be solved by the utility model is to provide a self-drying bottom-returning single-jet printing module single-sheet digital inkjet printer with an ingenious structural design, which adopts a set of printing modules to achieve single-sided or double-sided printing of a single sheet of paper, can effectively dry the printed surface and the dried paper is not easy to wrinkle, and is particularly suitable for the printing needs of high-end products.

[0008] In order to solve the above technical problems, the technical solution of the utility model is: a self-drying bottom-returning single-printing module single-sheet digital inkjet printer, comprising a paper feeding conveyor belt, a printing roller is arranged downstream of the paper feeding conveyor belt, a printing module is arranged above the printing roller, a traction chain is arranged below the printing roller, and the printing roller and the traction chain are respectively equipped with paper gripping teeth for handing over and transferring paper; a suction shaping belt extending along the traction direction is arranged below the front section of the traction chain, and a drying channel for the printing paper to pass through is formed between the front section of the traction chain and the front section of the suction shaping belt, the front section of the traction chain and the front section of the suction shaping belt run in the same direction and at the same speed, and a drying mechanism is arranged above the drying channel; a paper return output position and a paper collection output position are provided on the transmission path of the traction chain, and a paper return mechanism is arranged between the paper return output position of the traction chain and the input end of the paper feeding conveyor belt.

[0009] As a preferred technical solution, the paper returning mechanism includes a turning drum installed below the paper returning output position of the traction chain. A first suction belt is installed below the turning drum, and a second suction belt is installed below the input end of the paper feeding conveyor belt. A paper transfer mechanism is arranged between the output end of the first suction belt and the input end of the second suction belt. The turning drum can be a suction drum or a gripper drum.

[0010] As a preferred technical solution, the paper transfer mechanism includes a paper temporary storage plate installed at the output end of the first suction belt, and a paper feeding roller mechanism or a paper laying nozzle is installed above the paper temporary storage plate.

[0011] As one of the preferred technical solutions, a paper powder cleaning mechanism is arranged between the paper feeding conveyor belt and the printing drum.

[0012] As a preferred technical solution, the paper powder cleaning mechanism includes a first drum and a second drum. The first drum is connected to the output end of the paper feeding conveyor belt, and the second drum is respectively connected to the first drum and the printing drum; a cleaning roller is rotatably installed above the first drum, and a cleaning channel for the printing paper to pass through is formed between the surface of the cleaning roller and the surface of the first drum. When the printing paper passes through the cleaning channel, the roller surface of the cleaning roller contacts the surface of the printing paper.

[0013] As a preferred technical solution, a dust collection cover is arranged on the periphery of the cleaning roller, and a suction port is opened on the dust collection cover.

[0014] As another preferred technical solution, a coating mechanism is arranged between the paper feeding conveyor belt and the printing drum.

[0015] As a preferred technical solution, the coating mechanism includes a first drum and a second drum. The first drum is connected to the output end of the paper feeding conveyor belt, and the second drum is respectively connected to the first drum and the printing drum; a first coating roller is rotatably installed above the first drum, and a coating channel for the printing paper to pass through is formed between the surface of the first coating roller and the surface of the first drum. When the printing paper passes through the coating channel, the roller surface of the first coating roller contacts the surface of the printing paper; a second coating roller is cooperatively installed on the side of the first coating roller, and a metering roller is cooperatively installed on the side of the second coating roller, and a liquid supply gap is formed between the second coating roller and the metering roller.

[0016] As a preferred technical solution, the metering roller is connected with a liquid supply gap adjusting mechanism.

[0017] As a preferred technical solution, the drying mechanism is arranged in the area between the forward section and the return section of the traction chain.

[0018] As a preferred technical solution, a heat dissipation box is arranged below the drying channel.

[0019] Compared with the prior art, the utility model has at least the following beneficial effects:

[0020] (1) Through innovative structural design, a traction chain is arranged below the printing drum in cooperation, and a suction air shaping belt extending along the traction direction is arranged below the forward section of the traction chain. A drying channel for the printing paper to pass through is formed between the forward section of the traction chain and the forward section of the suction air shaping belt. The forward section of the traction chain and the forward section of the suction air shaping belt run in the same direction and at the same speed. A drying mechanism is arranged above the drying channel. In this way, after the paper completes the front printing operation, the paper is transferred from the printing drum to the traction chain by handover. The gripper tooth row on the traction chain grabs the paper head, and the paper tail is adsorbed by the suction air shaping belt. The whole paper is fully stretched and adsorbed and shaped under the joint action of the gripper tooth row and the suction air shaping belt. During the process of the paper moving forward with the traction chain, the drying mechanism dries the ink on the fully stretched printed surface. In this way, after the ink on the printed surface of the paper is dried, the paper is not easy to wrinkle, greatly improving the printing accuracy and quality during reverse printing. At the same time, since the forward section of the traction chain and the forward section of the suction air shaping belt run in the same direction and at the same speed, during the paper transfer process, on the one hand, the contact surface between the paper and the suction air shaping belt will not be worn due to relative displacement, and on the other hand, it can also ensure the balance between the pulling force formed by the gripper tooth row on the paper and the adsorption force formed by the suction air shaping belt on the paper, and no paper jamming problem will occur, thus ensuring the stability of paper transfer.

[0021] (2) By arranging a traction chain below the printing drum in cooperation, there are a paper return output position and a paper collection output position on the transmission path of the traction chain. A paper return mechanism is arranged between the paper return output position of the traction chain and the input end of the paper feeding conveyor belt. In this way, the whole machine only needs to be equipped with a set of printing modules, which can not only realize the single-sided printing operation of single sheets of paper, but also realize the front and back double-sided printing operation of single sheets of paper. When double-sided printing is required, the gripper tooth row of the traction chain transfers the paper that has completed the front printing to the paper return mechanism at the paper return output position. After the paper return mechanism returns the paper to the paper feeding conveyor belt, the paper is turned over, so as to perform reverse printing; when only single-sided printing is required or double-sided printing is completed, the gripper tooth row of the traction chain releases the printed paper to the paper collection table at the paper collection output position, so as to perform the paper collection operation. The overall structural design is ingenious, and the equipment investment cost is low.

[0022] (3) For the first time, a paper dust cleaning mechanism is set on a single-sheet digital inkjet printer that uses rollers to transfer paper. When the paper passes through the cleaning channel formed between the cleaning roller and the surface of the first roller, the roller surface of the cleaning roller rotating at high speed comes into instantaneous contact with the surface of the paper being conveyed forward synchronously. Under the action of high-speed airflow and friction, the paper dust on the paper surface and the paper fluff remaining at the edges of the paper can be quickly removed online. The desorbed paper dust and paper fluff are then centrally discharged to the outside through the dust collection hood. In this way, when the paper is transferred to the printing roller through the second roller for printing operations, the surface of the paper that has been cleaned is exactly the printing surface, which can avoid the problem of the paper dust on the printing surface being lifted by the high-speed airflow and clogging the inkjet head, thus effectively guaranteeing the print quality and efficient printing, and at the same time extending the service life of the inkjet head.

[0023] (4) For the first time, a coating mechanism is set on a single-sheet digital inkjet printer that uses rollers to transfer paper. By cooperating with the metering roller and the second coating roller, different coating thicknesses can be achieved. The first coating roller further distributes the coating liquid on the surface of the roller evenly. When the paper fed sheet by sheet through the paper feeding unit passes through the coating channel formed between the first coating roller and the surface of the first roller, the first coating roller can evenly coat the coating liquid on the paper surface, eliminating the need to set up a separate coating process and equipment, greatly improving the work efficiency and reducing the equipment investment and production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them:

[0025] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention;

[0026] Figure 2 is a state reference diagram when the paper is fully stretched, adsorbed and shaped under the combined action of the traction chain and the air suction shaping belt, and the drying mechanism dries the printing surface of the paper;

[0027] Figure 3 is a schematic structural diagram of the paper dust cleaning mechanism in Embodiment 1 of the present invention;

[0028] Figure 4 is a schematic structural diagram of Embodiment 2 of the present invention;

[0029] Figure 5 is a schematic structural diagram of Embodiment 3 of the present invention;

[0030] Figure 6 is a schematic structural diagram of the coating mechanism in Embodiment 3 of the present invention.

[0031] In the figure: 1 - paper feeding conveyor belt; 2 - printing cylinder; 3 - printing module; 4 - traction chain; 5 - air suction shaping belt; 6 - printing paper; 7 - drying mechanism; 8 - turning cylinder; 9 - first air suction belt; 10 - second air suction belt; 11 - paper temporary storage board; 12 - first cylinder; 13 - second cylinder; 14 - cleaning roller; 15 - dust collection hood; 16 - air suction port; 17 - first coating roller; 18 - second coating roller; 19 - metering roller; 20 - liquid supply gap adjustment mechanism; 21 - paper laying nozzle; 22 - paper feeding roller; 23 - heat dissipation box. Detailed implementation mode

[0032] The following further elaborates on the present utility model in conjunction with the accompanying drawings and embodiments. In the following detailed description, only some exemplary embodiments of the present utility model are described by way of illustration. Undoubtedly, those of ordinary skill in the art can recognize that the described embodiments can be modified in various different ways without departing from the spirit and scope of the present utility model. Therefore, the drawings and description are illustrative in nature and not used to limit the protection scope of the claims.

[0033] Embodiment 1

[0034] As Figure 1 shown, a self-drying down-return single-printing-module single-sheet digital inkjet printer includes a paper feeding conveyor belt 1. A printing cylinder 2 is arranged downstream of the paper feeding conveyor belt 1, and a printing module 3 is arranged above the printing cylinder 2. The printing paper is fed from the paper feeding conveyor belt 1 to the printing cylinder 2; the printing module 3 performs printing operations on the paper coated on the printing cylinder 2; a traction chain 4 is arranged in cooperation below the printing cylinder 2, and gripper jaw rows are respectively installed on the printing cylinder 2 and the traction chain 4, and the handover and transfer of the paper are realized through the opening and closing of the gripper jaw rows; an air suction shaping belt 5 extending along the traction direction is arranged below the forward section of the traction chain 4, and a drying channel for the printing paper 6 to pass through is formed between the forward section of the traction chain 4 and the forward section of the air suction shaping belt 5. The forward section of the traction chain 4 and the forward section of the air suction shaping belt 5 run in the same direction and at the same speed, and a drying mechanism 7 is arranged above the drying channel. To effectively save occupied space and improve drying efficiency, the drying mechanism 7 is arranged in the area between the forward section and the return section of the traction chain 4. A heat dissipation box 23 is arranged below the drying channel to effectively dissipate the heat generated by the drying mechanism 7.

[0035] Among them, the drying mechanism 7 can adopt a drying box, and heating tubes are installed in the drying box; of course, the drying mechanism can also adopt other drying methods such as hot air drying, and they should all fall within the protection scope of the present utility model. The air suction shaping belt 5 can be realized by an air suction belt with a smooth surface and evenly distributed air suction holes to achieve its corresponding functions.

[0036] Refer toFigure 2 After the printing paper 6 completes the front-side printing operation, the paper is transferred from the printing cylinder 2 to the traction chain 4. The gripper jaw row on the traction chain 4 grips the leading edge of the paper, and the trailing edge of the paper is adsorbed by the air-suction shaping belt 5. Under the combined action of the traction of the traction chain 4 and the adsorption force of the air-suction shaping belt 5, the entire paper is fully stretched and adsorbed and shaped. During the forward movement of the paper along with the traction chain 4, the drying mechanism 7 dries the ink on the fully stretched printed surface. In this way, after the ink on the printed surface of the paper is dried, the paper is not likely to wrinkle, greatly improving the printing accuracy and quality during subsequent reverse-side printing. At the same time, since the forward section of the traction chain 4 and the forward section of the air-suction shaping belt 5 run in the same direction and at the same speed, during the paper transfer process, on the one hand, the contact surface between the paper and the air-suction shaping belt 5 will not be worn due to relative displacement, and on the other hand, it can also ensure the balance between the pulling force formed by the gripper jaw row on the paper and the adsorption force formed by the air-suction shaping belt on the paper, and no paper jamming problem will occur, thus ensuring the stability of paper transfer.

[0037] Reference Figure 1 On the transmission path of the traction chain 4, there are a paper-return output position (at point A) and a sheet-fed output position (at point B). A paper-return mechanism is provided between the paper-return output position of the traction chain 4 and the input end of the sheet-fed conveyor belt 1. The paper-return mechanism includes a turning drum 8 installed below the paper-return output position (at point A) of the traction chain 4. The turning drum 8 can be an air-suction drum or a gripper jaw drum; a first air-suction belt 9 is installed below the turning drum 8, and a second air-suction belt 10 is installed below the input end of the sheet-fed conveyor belt 1. A paper transfer mechanism is provided between the output end of the first air-suction belt 9 and the input end of the second air-suction belt 10, and the paper output from the first air-suction belt 9 is transferred and conveyed to the second air-suction belt 10 through the paper transfer mechanism.

[0038] Reference Figure 1 In this embodiment, the paper transfer mechanism includes a paper temporary storage board 11 installed at the output end of the first air-suction belt 9, and a paper swinging nozzle 21 is installed above the paper temporary storage board 11. After the paper exits the first air-suction belt 9 and enters the paper temporary storage board 11, when the trailing edge reaches the set position, the paper swinging nozzle 21 sucks the trailing edge and swings upward to transfer and convey it to the second air-suction belt 10. At this time, the trailing edge is switched to the leading edge, and the paper is re-transferred to the sheet-fed conveyor belt 1 by the second air-suction belt 10.

[0039] When double-sided printing is required, the printing paper 6 is conveyed from the paper feeding conveyor belt 1 to the printing cylinder 2. The front side of the paper wrapped around the printing cylinder 2 is subjected to front-side printing operation by the printing module 3. After the front-side printing operation of the printing paper 6 is completed, the paper is transferred from the printing cylinder 2 to the traction chain 4. The gripper jaws on the traction chain 4 transfer the paper that has completed the front-side printing to the reversing cylinder 8 at the paper returning output position (at position A). After the reversing cylinder 8 sucks the paper head, the paper is transferred to the first air suction belt 9 and then the paper is turned over. The turned-over paper is then successively transferred back to the paper feeding conveyor belt 1 by the first air suction belt 9, the paper transfer mechanism, and the second air suction belt 10. The paper feeding conveyor belt 1 conveys the paper to the printing cylinder 2 again, and the printing module 3 performs reverse-side printing on the paper. If only single-sided printing is required or when paper collection operation is needed after double-sided printing is completed, the gripper jaws on the traction chain 4 release the printed paper to the paper collection table at the paper collection output position (at position B), thereby performing the paper collection operation. In this way, only one set of printing module 3 needs to be configured for the whole machine, which can not only realize single-sided printing operation of single sheets of paper, but also realize single-sided and double-sided printing operations of single sheets of paper. The overall structure is ingeniously designed and the equipment investment cost is low.

[0040] In this embodiment, a paper powder cleaning mechanism is installed between the paper feeding conveyor belt 1 and the printing cylinder 2. Refer to Figure 3 , the paper powder cleaning mechanism includes a first cylinder 12 and a second cylinder 13. The first cylinder 12 is connected to the output end of the paper feeding conveyor belt 1, and the second cylinder 13 is respectively connected to the first cylinder 12 and the printing cylinder 2. Gripper jaw rows for biting and transferring the paper are respectively installed on the first cylinder 12, the second cylinder 13, and the printing cylinder 2. A cleaning roller 14 is rotatably installed above the first cylinder 12. A cleaning channel for a single sheet of paper to pass through is formed between the surface of the cleaning roller 14 and the surface of the first cylinder 12. When the paper passes through the cleaning channel, the roller surface of the cleaning roller 14 is in contact with the surface of the paper.

[0041] Refer to again Figure 3 , a dust collection hood 15 is provided on the periphery of the cleaning roller 14. An air suction port 16 is opened on the dust collection hood 15. The air suction port 16 is connected to a negative pressure fan. Through the dust collection hood 15, it is convenient to centrally collect and discharge the paper powder and paper fluff detached from the paper surface to the outside, avoiding the re-aggregation and sedimentation of paper powder or paper fluff on the paper surface to form secondary pollution.

[0042] The specific working principle of this paper powder cleaning mechanism is as follows: The papers output one by one from the paper feeding conveyor belt 1 are picked up by the gripper jaw row on the first roller 12 at the paper head. Then the papers are wrapped around the surface of the first roller 12 and rotate with the roller. When the papers pass through the cleaning channel formed between the cleaning roller 14 and the surface of the first roller 12, the roller surface of the cleaning roller 14 rotating at high speed makes instantaneous contact with the surface of the papers being conveyed forward synchronously. Under the action of high-speed air flow and friction, the paper powder on the surface of the papers and the paper fluff remaining at the edges of the papers can be quickly removed online. The desorbed paper powder and paper fluff are then centrally discharged to the outside through the dust collecting hood 15. In this way, when the papers are transferred through the second roller 13 and then reach the printing roller 2 for printing operations, the surface of the papers that has been cleaned is exactly the printing surface, which can avoid the problem that the paper powder on the printing surface is lifted by the high-speed air flow and causes the inkjet head to be blocked by the paper powder, thus effectively ensuring the quality of printed products and efficient printing, and at the same time extending the service life of the inkjet head.

[0043] The cleaning roller 14 is preferably a brush roller, and its rotation direction is the same as that of the first roller 12. In this way, when the papers pass through the channel between the cleaning roller 14 and the first roller 12, the paper conveying direction is opposite to the rotation wiping direction of the cleaning roller 14. On the one hand, it can increase the relative linear speed of the contact surface between the papers and the cleaning roller 14, thus forming an "air knife" effect to accelerate the separation of the paper powder on the surface of the papers, and further improve the cleaning effect of the paper surface. On the other hand, the rotation wiping direction is from the paper head end to the paper tail end. After the paper head end is picked up by the jaw row, the papers will not form wrinkles due to friction.

[0044] Embodiment Two

[0045] Reference Figure 4 , the structural principle of this embodiment is basically the same as that of Embodiment One, and the same parts will not be described again. The only difference is that in this embodiment, the paper transfer mechanism includes a paper temporary storage plate 11 and two relatively arranged paper feeding rollers 22. The upper paper feeding roller is the driving roller, and the lower paper feeding roller is the driven roller, and the lower paper feeding roller can swing. After the papers are output from the first suction belt 9, they enter the paper temporary storage plate 11. When the paper tail reaches the set position, the lower paper feeding roller 22 swings upward, and under the action of the two paper feeding rollers, the papers are transferred and conveyed to the second suction belt 10. At this time, the paper tail is switched to the paper head, and the papers are re-transferred from the second suction belt 10 to the paper feeding conveyor belt 1, thus completing the paper transfer.

[0046] Embodiment Three

[0047] Reference Figure 5 , the structural principle of this embodiment is basically the same as that of Embodiment One, and the same parts will not be described again. The only difference is that in this embodiment, a coating mechanism is installed between the paper feeding conveyor belt 1 and the printing roller 2, which replaces the paper powder cleaning mechanism in Embodiment One to meet the high-end printing requirements of different models and different papers.

[0048] Reference Figure 6 The coating mechanism includes a first roller 12 and a second roller 13. The first roller 12 is connected to the output end of the paper feeding conveyor belt 1, and the second roller 13 is respectively connected to the first roller 12 and the printing roller 2. Gripper bar rows for gripping and transferring paper are respectively installed on the first roller 12 and the second roller 13. A first coating roller 17 is rotatably installed above the first roller 12. A coating channel for a single sheet of paper to pass through is formed between the surface of the first coating roller 17 and the surface of the first roller 12. When the paper passes through the coating channel, the roller surface of the first coating roller 17 contacts the surface of the paper. A second coating roller 18 (preferably a hard rubber roller) is cooperatively installed on the side of the first coating roller 17, and a metering roller 19 (preferably a rubber roller) is cooperatively installed on the side of the second coating roller 18. A liquid supply gap D is formed between the second coating roller 18 and the metering roller 19.

[0049] The metering roller 19 is connected to a liquid supply gap adjusting mechanism 20. By adjusting the distance between the metering roller 19 and the second coating roller 18 through the liquid supply gap adjusting mechanism 20, different coating thicknesses of the coating can be achieved. During the coating operation, the coating liquid is transported to the liquid supply gap by the conveying mechanism. As the second coating roller 18 rotates, the coating liquid is coated on the surface of the second coating roller 18. The second coating roller 18 transfers the coating liquid to the first coating roller 17, which can further distribute the coating liquid on the surface of the roller body evenly, improving the axial and radial uniformity. In this way, when the paper passes through the coating channel formed between the surface of the first coating roller 17 and the first roller 12, the first coating roller 17 evenly coats the coating liquid on the surface of the paper, eliminating the need for a separate coating process and equipment, greatly improving the working efficiency, and reducing the equipment investment and production cost.

[0050] In summary, the overall structure of the present utility model is ingeniously and reasonably designed. The whole machine only needs to be equipped with a set of printing modules, which can not only realize the single-sided printing operation of a single sheet of paper, but also realize the front and back double-sided printing operation of a single sheet of paper. Through the joint cooperation of the traction chain and the suction air shaping belt, the drying effect of the printed surface can be effectively guaranteed, and the dried paper is not easy to wrinkle. The paper transfer stability is good. At the same time, it can also take into account the on-line cleaning or coating function of the paper powder, and is particularly suitable for the high-quality printing requirements of high-end products.

[0051] The above is only a schematic specific embodiment of the present utility model, and is not intended to limit the scope of the present utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present utility model shall fall within the scope of protection of the present utility model.

Claims

1. Self-drying down-feed single-jet printing module single-sheet digital inkjet printer, characterized in that: It includes a sheet feeding conveyor belt, a printing cylinder is arranged downstream of the sheet feeding conveyor belt, a printing module is arranged above the printing cylinder, a traction chain is arranged in cooperation with the lower part of the printing cylinder, and gripper bar trains for transferring and delivering sheets are respectively installed on the printing cylinder and the traction chain; a suction air shaping belt extending along the traction direction is arranged below the forward running section of the traction chain, a drying channel for the printed sheet to pass through is formed between the forward running section of the traction chain and the forward running section of the suction air shaping belt, the forward running section of the traction chain and the forward running section of the suction air shaping belt run in the same direction and at the same speed, and a drying mechanism is arranged above the drying channel; a paper returning output position and a sheet collecting output position are provided on the transmission path of the traction chain, and a paper returning mechanism is arranged between the paper returning output position of the traction chain and the input end of the sheet feeding conveyor belt.

2. The self-drying bottom-return single-spray printing module single-sheet digital inkjet printer according to claim 1, characterized in that: The paper returning mechanism includes a turning cylinder installed below the paper returning output position of the traction chain, a first suction air belt is installed below the turning cylinder, a second suction air belt is installed below the input end of the sheet feeding conveyor belt, and a paper transfer mechanism is arranged between the output end of the first suction air belt and the input end of the second suction air belt.

3. The self-drying down-feed single-spraying module single-sheet digital inkjet printer according to claim 2, wherein: The paper transfer mechanism includes a paper temporary storage plate installed at the output end of the first suction air belt, and a paper conveying roller mechanism or a paper placing nozzle is installed above the paper temporary storage plate.

4. The single-sheet digital inkjet printer with a self-drying downward-return single-spray printing module according to claim 1, characterized in that: A paper powder cleaning mechanism is arranged between the sheet feeding conveyor belt and the printing cylinder.

5. The self-drying down-feed single-spray printing module single-sheet digital inkjet printer according to claim 4, wherein: The paper powder cleaning mechanism includes a first cylinder and a second cylinder, the first cylinder is connected to the output end of the sheet feeding conveyor belt, and the second cylinder is respectively connected to the first cylinder and the printing cylinder; a cleaning roller is rotatably installed above the first cylinder, a cleaning channel for the printed sheet to pass through is formed between the surface of the cleaning roller and the surface of the first cylinder, and when the printed sheet passes through the cleaning channel, the roller surface of the cleaning roller contacts the surface of the printed sheet.

6. The self-drying downward-return single-spraying module single-sheet digital inkjet printer according to claim 5, wherein: A dust collection cover is arranged on the periphery of the cleaning roller, and a suction air port is opened on the dust collection cover.

7. The self-drying down-feed single-spray printing module single-sheet digital inkjet printer according to claim 1, characterized in that: A coating mechanism is arranged between the sheet feeding conveyor belt and the printing cylinder.

8. The self-drying down-feed single spray-printing module single-sheet digital inkjet printer according to claim 7, wherein: The coating mechanism includes a first cylinder and a second cylinder, the first cylinder is connected to the output end of the sheet feeding conveyor belt, and the second cylinder is respectively connected to the first cylinder and the printing cylinder; a first coating roller is rotatably installed above the first cylinder, a coating channel for the printed sheet to pass through is formed between the surface of the first coating roller and the surface of the first cylinder, and when the printed sheet passes through the coating channel, the roller surface of the first coating roller contacts the surface of the printed sheet; a second coating roller is installed in cooperation with the side part of the first coating roller, a metering roller is installed in cooperation with the side part of the second coating roller, and a liquid supply gap is formed between the second coating roller and the metering roller.

9. The self-drying downward-return single-spray printing module single-sheet digital inkjet printer according to claim 8, characterized in that: The metering roller is connected with a liquid supply gap adjusting mechanism.

10. The single-sheet digital inkjet printer with a self-drying downward-return single-spray printing module according to any one of claims 1 to 9, characterized in that: A heat dissipation box is arranged below the drying channel.

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