Sheet-fed double-sided inkjet printer

Abstract

The present invention provides a single-sheet double-sided inkjet printer, comprising a water-based inkjet system arranged above a printing cylinder and a paper receiving part on one side, a paper feeding part for feeding paper, a flipping part for flipping paper, and a phase adjustment mechanism for adjusting the phase of paper are respectively arranged on the other side of the printing cylinder, and the paper feeding part and the flipping part are respectively located at the upper and lower ends of the phase adjustment mechanism, a single-sided paper gripping mechanism and a double-sided paper gripping mechanism are staggeredly installed on the outer wall of the printing cylinder, and a single-sided cam and a double-sided cam are arranged at one end of the printing cylinder, when single-sided printing is required, the single-sided paper gripping mechanism and the double-sided paper gripping mechanism both cooperate with the single-sided cam to grip the paper; when double-sided printing is required, the double-sided paper gripping mechanism cooperates with the double-sided cam to grip the paper to realize the double-sided switching of a single sheet of paper. The single-sheet double-sided inkjet printer described in the present invention adopts a roller method and cooperates with an advanced flipping mechanism to realize double-sided printing, ensure printing accuracy and printing quality, and greatly reduce the cost of the equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of printing machines, and in particular relates to a single-sheet double-sided inkjet printer. Background Art

[0002] At present, the mature products of single-sheet inkjet digital printing machines are mainly Konica Minolta's KM1, which also uses a set of nozzles to achieve double-sided printing. After the front side of the paper is printed, it is turned over and returned to the printing cylinder through the paper path for reverse printing. However, it can only use a single paper specification and cannot use other specifications of paper. The working principle of the existing drum inkjet printing machine is as follows: the drums are gear-driven, and the paper head is held by the paper gripper on the drum to drive the paper to rotate. At the tangent point of the drum, the drum transfers the paper, and the paper is transferred from one drum to another. In this process, the paper head is always facing the paper head to ensure that the paper is stationary relative to the drum. The inkjet system can perform inkjet printing according to the picture as long as it detects the running speed of the drum. When double-sided printing is required, when the paper is transferred to the flip drum part, the position where the flip drum holds the paper is not the head of the paper, but the tail of the paper. The paper is turned over, and the normal paper transfer and handover continues below, and it is transferred to the printing drum again for reverse printing. Therefore, this paper transfer path is a closed loop. If the paper specifications are changed, after the flip roller grabs the tail of the paper, it will not be able to accurately transfer it to the position of the gripper row of the next roller. Therefore, the biggest disadvantage of Konica Minolta KM1 is that the paper specifications are single. When printing on both sides, only one specification of paper can be used, and only the pre-designed specification paper can be used. Users cannot use other specifications of paper, which limits the user's flexibility and increases the user's cost. Summary of the invention

[0003] In view of this, the present invention aims to provide a sheet-fed double-sided inkjet printer to solve the problem that a sheet-fed digital printing machine can only use one specification of paper for double-sided printing.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A single-sheet double-sided inkjet printer comprises an aqueous inkjet system arranged above a printing cylinder and a paper receiving part arranged on one side, a paper feeding part for feeding paper, a turning part for turning over paper, and a phase adjustment mechanism for adjusting the phase of paper are respectively arranged on the other side of the printing cylinder, and the paper feeding part and the turning part are respectively located at the upper and lower ends of the phase adjustment mechanism, a single-sided paper gripping mechanism and a double-sided paper gripping mechanism are staggeredly installed on the outer wall of the printing cylinder, a single-sided cam and a double-sided cam are arranged at one end of the printing cylinder, the double-sided cam is connected to a cylinder, and the cylinder signal is connected to a controller; when single-sided printing is required, the single-sided paper gripping mechanism and the double-sided paper gripping mechanism both cooperate with the single-sided cam to grip paper; when double-sided printing is required, only the double-sided paper gripping mechanism cooperates with the double-sided cam to grip paper, thereby realizing double-sided switching of a single sheet of paper.

[0006] Furthermore, a single-diameter paper transfer cylinder and an even-numbered reversing cylinder are provided on one side of the printing cylinder, and the even-numbered paper transfer cylinder is located above the driven paper transfer sprocket of the phase adjustment mechanism, and the active paper transfer sprocket of the phase adjustment mechanism is located above the paper transfer cylinder of the reversing part.

[0007] Furthermore, the printing roller is provided with a paper tail adsorption device, and the paper tail adsorption device is provided with a suction seat for adsorbing paper, the upper surface of the suction seat is tangent to the diameter of the roller, and the two can move relative to each other along the circumference of the roller.

[0008] Furthermore, the flipping part includes a width adjustment unit and an even-number flipping roller, a flipping roller and a paper transfer roller arranged in parallel on one side thereof. The width adjustment unit is used to adjust the width of the paper. A cam adjustment unit for adjusting the paper head cam is installed on one side of the even-number flipping roller. Signals of the width adjustment unit and the cam adjustment unit are respectively connected to the controller.

[0009] Furthermore, the cam adjustment unit includes a driving gear and a cam locking structure for limiting the driving gear. The cam adjustment motor and the paper head cam are fixed to both sides of the driving gear respectively. The cam adjustment motor and the cam locking structure are respectively connected to the controller by signal.

[0010] Furthermore, the width adjustment unit includes a width adjustment even-number adjustment gear, a width adjustment gear, a paper transfer adjustment gear, a width locking structure and a width adjustment motor. The two ends of the bearing of the flipping roller are respectively fixedly sleeved with the width adjustment gear and the flipping roller driving gear, the flipping roller driving gear is fixedly connected to the width adjustment motor, and a width locking structure is provided on the outer side of the width adjustment gear, and the two sides are respectively meshed with the width adjustment even-number adjustment gear and the paper transfer adjustment gear, the inside of the paper transfer adjustment gear is fixedly sleeved with the bearing of the paper transfer roller, and the inside of the width adjustment even-number adjustment gear is fixedly sleeved with the bearing of the even-number flipping roller, and the width locking structure and the width adjustment motor are respectively connected to the controller by signals.

[0011] Furthermore, the phase adjustment mechanism includes two symmetrically arranged chain tensioning units, and a guide rail and a driving unit are provided on the outer side of the chain tensioning unit. The guide rail is installed on an external device, so that the tensioning plate of the chain tensioning unit can move left and right along the guide rail under the drive of the adjustment unit, and the driving unit signal is connected to the controller; each chain tensioning unit is respectively provided with a driven paper transfer sprocket and an active paper transfer sprocket at the upper and lower ends, and the three form a transmission structure, and a paper gripper row and a guide plate are installed between the two chain tensioning units.

[0012] Compared with the prior art, the single-sheet double-sided inkjet printer of the present invention has the following advantages:

[0013] (1) The single-sheet double-sided inkjet printer described in the present invention adopts a roller method and cooperates with an advanced flipping mechanism to achieve double-sided printing, ensure printing accuracy and printing quality, and greatly reduce the cost of the equipment; at the same time, it also reduces the user's use and maintenance costs.

[0014] (2) Compared with a web-fed inkjet printer, the sheet-fed double-sided inkjet printer of the present invention provides users with greater flexibility and a wider range of paper specifications and varieties to choose from.

[0015] (3) The sheet-fed double-sided inkjet printer described in the present invention has a format adjustment mechanism that makes the paper specifications no longer restricted, thereby reducing the workload and time of subsequent processing steps, improving production efficiency and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0017] Figure 1 This is a schematic diagram of a sheet-fed double-sided inkjet printer according to an embodiment of the present invention;

[0018] Figure 2 It is a side view of the single-sheet double-sided inkjet printer according to an embodiment of the present invention;

[0019] Figure 3 This is a working principle diagram of a sheet-fed double-sided inkjet printer according to an embodiment of the present invention;

[0020] Figure 4 A schematic diagram of a printing cylinder according to an embodiment of the present invention;

[0021] Figure 5 for Figure 4 The enlarged view of point A in the middle;

[0022] Figure 6 for Figure 4 The enlarged view of point B in the middle;

[0023] Figure 7 is a schematic diagram of a drum according to an embodiment of the present invention;

[0024] Figure 8 Schematic diagram of the flip part according to the embodiment of the present invention Figure 1 ;

[0025] Fig. 9 for Figure 8 Enlarged view of point C in the middle;

[0026] Fig.10 Schematic diagram of the flip part according to the embodiment of the present invention Figure 2 ;

[0027] Fig.11 A schematic diagram of a turning drum according to an embodiment of the present invention;

[0028] Fig.12 A schematic diagram of a format adjustment unit according to an embodiment of the present invention;

[0029] Fig.13 is a cross-sectional view of a width adjustment gear according to an embodiment of the present invention;

[0030] Fig.14 Schematic diagram of the phase adjustment mechanism according to an embodiment of the present invention Figure 1 ;

[0031] Fig.15 Schematic diagram of the phase adjustment mechanism according to an embodiment of the present invention Figure 2 .

[0032] Description of reference numerals:

[0033] 1-printing roller; 11-roller; 111-gap; 112-gas distribution valve; 113-intake seat; 1131-intake hole; 114-air inlet; 115-fixed seat; 12-single-sided tooth row; 13-single-sided tooth row cam roller; 131-single-sided cam roller; 14-double-sided tooth row cam roller; 141-first double-sided roller; 142-second double-sided roller; 15-cylinder; 16-double-sided cam; 17-single-sided cam; 18-double-sided tooth row; 19-adjusting gear.2-turning part; 21-even-fold turning roller; 211-paper tail cam; 212-paper tail gripping teeth; 213-paper tail tensioning tooth pad; 214-paper tail tooth pad cam; 215-paper head gripping teeth; 216-even-fold adjustment gear; 217-even-fold bearing; 218-No. 1 rolling paper board; 219-No. 2 rolling paper board; 2110-paper head cam; 2111-even-fold support plate; 22-turning roller; 221-support plate; 222-end plate; 223-bearing; 224-turning roller paper gripping teeth row; 2241-No. 1 gear block; 2242-No. 2 gear block; 2243-paper gripping shaft; 2244-tooth Pad; 2245-paper gripper; 225-turning roller driving gear; 226-turning roller cam; 23-paper transfer roller; 24-cam adjustment unit; 241-cam adjustment motor; 242-driving gear; 243-cam locking structure; 2431-cam locking cylinder; 2432-cam locking lever; 2433-pressing block; 25-width adjustment unit; 251-width adjustment even-number adjustment gear; 252-intermediate gear; 2521-intermediate gear No. 1; 2522-intermediate gear No. 2; 2523-intermediate gear No. 3; 2524-intermediate gear No. 4; 253-width adjustment gear; 2531- Interface; 2532-housing; 2533-No. 1 width gear; 2534-No. 2 width gear; 2535-plug-in block; 2536-limiting block; 2537-width adjustment connector; 254-paper transfer adjustment gear; 255-width locking structure; 2551-width locking lever; 2552-width locking cylinder; 256-width adjustment intermediate gear; 257-width adjustment motor; 3-phase adjustment mechanism; 31-guide plate; 32-chain tensioning unit; 321-tensioning chain; 322-tensioning plate; 3221-connector; 3222-limiting hole; 323-driven wheel; 324-driving wheel; 33-driven paper transfer sprocket; 34-paper gripper row; 35-guide rail; 36-adjustment unit; 361-adjustment motor; 362-driving member; 37-active paper transfer sprocket; 38-bracket; 39-locking limit unit; 391-limit rod; 392-locking cylinder; 393-locking lever; 310-limit plate; 4-paper transfer part; 41-even-number paper transfer roller; 42-single-diameter paper transfer roller; 5-aqueous inkjet system; 6-paper collection part; 61-paper collection roller; 62-paper collection tensioning wheel; 63-paper collection pile; 64-drying lamp group; 7-paper feeding part; 71-paper feeding shaft; 72-paper pile; 8-paper pressing wheel. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention 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 limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0038] Sheet-fed double-sided inkjet printer, such as Figures 1 to 15 As shown, it includes a printing roller 1, a turning part 2, a phase adjustment mechanism 3, a paper conveying part 4, an aqueous inkjet system 5 and a paper receiving part 6. The aqueous inkjet system 5 is arranged above the printing roller 1, and one side is respectively provided with a paper conveying part 4 for conveying paper, a turning part 2 for turning over paper, and a phase adjustment mechanism 3 for adjusting the phase of paper, and the paper conveying part 4 and the turning part 2 are respectively located on the upper and lower sides of the phase adjustment mechanism 3, and the other side of the printing roller 1 is provided with a paper receiving part 6.

[0039] The paper transfer part 4 includes an even-numbered paper transfer cylinder 41 and a plurality of single-diameter paper transfer cylinders 42 arranged in parallel with each other. The paper transfer cylinders are composed of three or more cylinders and are adjusted and confirmed according to the length of the paper path. The structures of the even-numbered paper transfer cylinders 41 and the single-diameter paper transfer cylinders 42 are both prior art.

[0040] like Figures 4 to 7As shown, the printing roller 1 includes a roller 11, a single-sided paper gripping mechanism, and a double-sided paper gripping mechanism. The single-sided paper gripping mechanism includes a single-sided tooth row 12 and a single-sided tooth row cam roller 13 connected thereto. The double-sided paper gripping mechanism includes a double-sided tooth row 18 and a double-sided tooth row cam roller 14 connected thereto. The single-sided tooth row 12 and the double-sided tooth row 18 are alternately arranged on the roller 11. A single-sided cam 17 and a double-sided cam 16 (which can be arranged in parallel or vertically) are arranged on one side of the roller 11. A cylinder 15 is installed on the outer side of the double-sided cam 16, and the signal of the cylinder 15 is connected to a controller. When single-sided printing is required, the single-sided tooth row cam roller 13 and the double-sided tooth row cam roller 14 both cooperate with the single-sided cam 17 to grip the paper. When double-sided printing is required, only the double-sided tooth row cam roller 14 cooperates with the double-sided cam 164 to change the action of the double-sided tooth row 18.

[0041] In order to effectively control the handover of paper and distinguish between single-sided and double-sided, the roller 11 adopts an even-numbered diameter roller at the position where single-sided and double-sided switching and distinction are required; the single-sided tooth row 12 on the roller 11 is responsible for holding the paper that needs single-sided printing, and the double-sided tooth row 18 is responsible for holding the paper that needs double-sided printing. The paper handover is controlled by increasing or decreasing the cam at the handover position. The roller 11 is provided with a paper tail adsorption device, and the paper tail adsorption device is provided with a suction seat 113 for adsorbing paper. The upper surface of the suction seat 113 is tangent to the diameter of the roller 11, and the two can move relative to each other along the circumference of the roller 11. Preferably, the suction seat 113 is provided with a plurality of suction holes 1131, and the upper surface of the suction seat 113 is tangent to the diameter of the roller 11. The suction holes 1131 are used to suck air to adsorb the paper on the surface of the roller 11.

[0042] The paper tail adsorption device also includes an adjusting gear 19 and an air distribution valve 112. The roller 11 is coaxially arranged with the adjusting gear 9. A plurality of suction seats 113 are arranged between the adjusting gear 9 and the base of the roller 11, and each suction seat 113 is fixedly connected to the adjusting gear 19. A plurality of gap groups are arranged on the outer wall of the roller 11. Each gap group is evenly distributed with a plurality of gaps 111 in the axial direction. A suction seat 113 is placed in each gap 111, and the suction seat 113 can reciprocate along the circumference of the outer wall of the roller 11 inside the gap 111 under the drive of an external force; the adjusting gear 19 is connected to the paper presetting mechanism, and the paper presetting mechanism automatically drives the adjusting gear 19 to run to a certain position according to the set paper size, so that the suction hole 1131 of the suction seat 113 is always aligned with the tail of the paper, and the tail is firmly adsorbed; the air distribution valve 112 is installed inside the roller 11, and the air distribution valve 112 connects the suction seat 113 with the air inlet 114 through the air pipe, and then connects with the air source, so that the suction air is reasonably divided into several parts. The suction force of the suction hole 1131 on the paper is kept uniform, ensuring the stability of the paper. At the same time, the structure reduces the requirement for negative pressure, which can save energy to a certain extent. In one embodiment, a plurality of mutually parallel fixing seats 115 are provided between the adjustment gear 19 and the base, and the fixing seats 115 are all fixedly connected to the adjustment gear 19 and do not contact the base. A plurality of suction seats 113 are evenly distributed above each fixing seat 115. The fixing seat 115 connects the suction seat 113 and the adjustment gear 19 together to play a connecting and fixing role.

[0043] The working principle of the printing roller paper tail suction device is as follows: the printing roller paper tail suction device of the present scheme is installed between two supporting mechanisms, the air inlet 114 is connected to the air source pipeline, the adjustment gear 19 is connected to the external paper presetting mechanism, and the user pre-sets the paper specifications through the paper presetting mechanism before starting the machine. The paper presetting mechanism drives the adjustment gear 19 to rotate to a suitable position, and the adjustment gear 19 rotates to drive the fixed seat 115 to move, thereby driving the suction seat 113 to move. Since the roller 11 is stationary, the suction seat 113 moves relative to the gap 111 along the outer diameter direction of the roller 11. When the paper presetting mechanism controls the adjustment gear 19 to stop moving, the relative position of the suction seat 113 and the gap 111 is stationary, ensuring that the position of the suction hole 1131 can suck the paper tail of this batch of paper.

[0044] The outer side of the adjustment gear 19 is provided with a single-sided cam 17 and a double-sided cam 16 in sequence, and a plurality of arc grooves are provided at the edge of the adjustment gear 19, and the arc grooves are used to install the single-sided tooth row cam roller 13 and the double-sided tooth row cam roller 14. In one embodiment, a limiting groove is provided on the side of the single-sided cam 17 close to the double-sided cam 16 to limit the position of the double-sided cam 16; the thickness of the limiting groove is the same as the thickness of the double-sided cam 16, and the cylinder 15 is installed on the external device. When the double-sided cam 16 is pressed into the limiting groove under the drive of the cylinder 15, the outer side of the double-sided cam 16 is flush with the outer side of the single-sided cam 17, making the various components of the equipment more compact, thereby saving equipment space. The control of the gripper row action is controlled by the cam, and the gripper row at the high point of the cam is closed, and the gripper row at the low point of the cam is opened. Specifically, a plurality of tooth row placement places are provided on the outer wall of the drum 11, and the tooth row placement places are used to install the single-sided tooth row 12 and the double-sided tooth row 18. The paper-gripping shaft of each group of tooth rows passes through an arc groove and is connected to a cam roller (the paper-gripping shaft of the double-sided tooth row 18 passes through an arc groove and is connected to the double-sided tooth row cam roller 14, and the paper-gripping shaft of the single-sided tooth row 12 passes through an arc groove and is connected to the single-sided tooth row cam roller 13). The coordination relationship and working principle of the cam and the opening and closing of the tooth row are all existing technologies and will not be repeated here. Please refer to the literature "Manufacturing method of opening and closing device of printing press tooth" or "Structure and adjustment of tooth of offset printing press".

[0045] There is only one single-sided cam roller 131 on the single-sided tooth row cam roller 13, which is only acted upon by the single-sided cam 17. Two cam rollers are installed side by side on the double-sided tooth row cam roller 14, namely the first double-sided roller 141 and the second double-sided roller 142, so that the double-sided tooth row cam roller 14 can be acted upon by the single-sided cam 17 and the double-sided cam 16.

[0046] The working principle of the single-sided and double-sided switching of the printing roller is as follows: in the initial state, the single-sided cam 17, the double-sided cam 16 and the cylinder 15 are all fixedly installed on the external supporting mechanism, and the roller 11 is movably connected to the external supporting mechanism through a bearing, and it is ensured that when the roller 11 rotates, both the single-sided tooth row 12 and the double-sided tooth row 18 can cooperate with the single-sided cam 17; the cylinder 15 is connected to the external air source, and the double-sided cam 16 is separated from the single-sided cam 17, which does not hinder the roller 11 from driving the single-sided tooth row 12 and the double-sided tooth row 18 to move. When single-sided printing is required, the paper on the roller has the same movement path, the single-sided tooth row 12 and the double-sided tooth row 18 have the same movement, and are opened and closed normally under the action of the single-sided cam 17. As the roller 11 drives the single-sided tooth row 12 and the double-sided tooth row 18 to rotate, the single-sided tooth row 12 and the first double-sided roller 141 will both contact and cooperate with the single-sided cam 17. When the single-sided tooth row cam roller 13 turns to the high point of the single-sided cam 17, the single-sided tooth row cam roller 13 will drive the single-sided tooth row 12 to close through the paper gripping shaft. When the single-sided tooth row cam roller 13 turns to the low point of the single-sided cam 17, the single-sided tooth row cam roller 13 will drive the single-sided tooth row 12 to open through the paper gripping shaft. Similarly, the first double-sided roller 141 will control the opening and closing of the double-sided tooth row 18, thereby gripping and releasing the paper. When double-sided printing is required, the staff controls the opening and closing of the double-sided tooth row 18 through the controller. The cylinder 15 moves. Since the cylinder 15 is installed on the external supporting mechanism, the double-sided cam 16 is pushed out when the cylinder 15 moves, so that the position of the double-sided cam 16 cooperates with the second double-sided roller 142. Specifically, as the roller 11 drives the single-sided tooth row 12 and the double-sided tooth row 18 to rotate, the single-sided tooth row 12 will not contact the double-sided cam 16, and the second double-sided roller 142 will contact the double-sided cam 16. When the second double-sided roller 142 rotates to the high point of the double-sided cam 16, the second double-sided roller 142 will drive the double-sided tooth row 18 to close through the paper-gripping shaft. When the second double-sided roller 142 rotates to the low point of the double-sided cam 16, the second double-sided roller 142 will drive the double-sided tooth row 18 to open through the paper-gripping shaft, thereby changing the action of the double-sided tooth row 18, and the paper is not handed over to the paper receiving part, but continues to rotate and handed over to the flip roller part.

[0047] like Figures 8 to 13 As shown, the flipping part 2 includes a format adjustment unit 25 and an even-number flipping roller 21, a flipping roller 22 and a paper transfer roller 23 installed in parallel on one side thereof. The format adjustment unit 25 is used to adjust the format of the paper, and a cam adjustment unit 24 for adjusting the paper head cam 2110 is installed on one side of the even-number flipping roller 21.

[0048] The even-number flip roller 21 includes a paper tail cam 211, a paper tail gripper 212, a paper tail tensioning tooth pad 213, a paper tail tooth pad cam 214, a paper head gripper 215, an even-number adjustment gear 216, an even-number bearing 217, a No. 1 rolling paper board 218, a No. 2 rolling paper board 219 and a paper head cam 2110. The even-number bearing 217 is externally sleeved with the even-number adjustment gear 216 and the even-number support plate 22111. A number of No. 1 rolling paper boards 218 and No. 2 rolling paper boards 219 are alternately arranged between the even-number adjustment gear 216 and the even-number support plate 22111. Each No. 1 rolling paper board 218 is fixedly connected to a paper tail gripper unit for gripping the paper tail, and each No. 2 rolling paper board 219 is fixedly connected to a paper head gripper unit for gripping the paper head.

[0049] Preferably, the paper tail gripping unit includes a paper tail cam 211, a paper tail gripping teeth 212, a paper tail tensioning tooth pad 213, and a paper tail tooth pad cam 214. The outer side of the even-number adjustment gear 216 is provided with a paper tail tooth pad 214 and a paper tail cam 211 in sequence. The paper tail tensioning tooth pad 213 and a paper tail gripping shaft are installed between the even-number adjustment gear 216 and the even-number support plate 22111. A plurality of paper tail gripping teeth 212 are evenly distributed on the paper tail gripping shaft. The positions of the paper tail gripping teeth 212 match the positions of the paper tail tensioning tooth pad 213, so that the paper tail gripping teeth 212 can be engaged with the paper tail tensioning tooth pad under the drive of an external force. 213 cooperates to complete the paper gripping and paper placing, the tail paper tensioning tooth pad 213 is fixedly connected to each No. 1 roller board 218; the roller arranged outside the tail paper gripping shaft cooperates with the tail paper cam 211 to complete the opening and closing control of the tail paper gripping teeth 212, and the roller outside the tail paper tensioning tooth pad 213 cooperates with the tail paper tooth pad cam 214 to complete the tensioning control of the tail paper tensioning tooth pad 213. The coordination relationship and working principle of the cam and the opening and closing of the gripping teeth row are all prior art, which will not be repeated here. Please refer to the literature "Manufacturing method of opening and closing device of gripping teeth of printing machine" or "Structure and adjustment of gripping teeth of offset printing machine". The structure of the head paper gripping unit and the tail paper gripping unit is exactly the same, which will not be repeated here. In order to facilitate the description of the working principle, the head paper gripping unit only marks the head paper gripping teeth 215 and the head paper cam 2110 in the figure. The even-number-fold turning roller 21 is a paper tail holding turning mechanism. The even-number-fold turning roller 21 mainly functions to transfer paper. During the transfer process, the paper head and paper tail are held and the paper is flattened.

[0050] The cam adjustment unit 24 includes a cam adjustment motor 241, a driving gear 242 and a cam locking structure 243. The cam adjustment motor 241 is fixedly connected to the driving gear 242. The driving gear 242 is coaxially arranged with the even-number flip roller 21, and the driving gear 242 is fixedly connected to the paper head cam 2110, thereby driving the paper head cam 2110 to rotate. The cam locking structure 243 is installed on an external supporting mechanism and is used to limit the driving gear 242. The cam adjustment motor 241 and the cam locking structure 243 are respectively connected to the controller by signals.

[0051] In one or more embodiments, the cam locking structure 243 includes a cam locking cylinder 2431, a cam locking lever 2432, and a pressure block 2433. The cam locking cylinder 2431 signal is connected to the controller, the cam locking cylinder 2431 is fixedly connected to the cam locking lever 2432, the cam locking lever 2432 is connected to the pressure block 2433 through a connecting rod, and the pressure block 2433 is located on the side of the driving gear 242 close to the paper head cam 2110. Preferably, the connecting rod is sleeved in the through hole of the external support mechanism, so that the cam locking lever 2432 and the paper head cam 2110 are respectively located on both sides of the external support mechanism, and will not affect the movement of the cam locking lever 2432. In one or more embodiments, the cam adjustment motor 241 is located on one side of the even-number flip roller 21, and the cam adjustment motor 241 is fixedly connected to the cam adjustment intermediate gear. The cam adjustment intermediate gear and the driving gear 242 make the position of the cam adjustment motor 241 not coaxial with the even-number bearing 217, thereby not affecting the connection between the even-number bearing 217 and the external device. This design makes the entire structure of the present solution more compact. The working principle of the cam adjustment unit 24 is as follows: the staff presets the paper according to the paper specifications to ensure that the paper tail can be accurately gripped during the flipping process. The paper preset data has been stored in the controller, and the staff only needs to input the parameters; the staff controls the cam adjustment motor 241 to work through the controller, and the cam adjustment motor 241 (preferably a servo motor) rotates through the cam adjustment intermediate gear and the drive gear 242. Since the drive gear 242 is fixedly connected to the paper head cam 2110, the paper head cam 2110 also rotates to the set position. After the controller determines that the cam adjustment motor 241 has reached the rotation angle (it can be achieved by installing a sensor to send a signal to the controller, or by the controller delay setting), the controller controls the cam locking cylinder 2431 to work, and the cam locking cylinder 2431 drives the cam locking lever 2432 to move outward, and the cam locking lever 2432 drives the pressure block 2433 to move outward until the pressure block 2433 presses the drive gear 242 and fixes the drive gear 242, thereby ensuring the stability of the cam adjustment unit 24 in the closed state.

[0052] The position of the paper head cam 2110 can ensure that the double turning roller 1 holds the paper head and paper tail of the paper. During the rotation of the even-number bearing 217, the paper tail gripper 212 flattens the paper. When it turns to the handover position, the turning roller 22 holds the paper tail and turns the paper over, completing the turning, and continues to rotate and transfer it to the paper transfer roller 23. The first rolling paper board 218 and the second rolling paper board 219 are both arc-shaped plates, which are convenient for paper transfer. The turning roller 22 is a single-diameter turning roller.

[0053] The flip roller 22 includes a support plate 221, an end plate 222, a flip roller paper gripper row 224 and a flip roller cam 226. The bearing 223 is fixedly sleeved on the outside of the plurality of support plates 221 and movably sleeved on the flip roller cam 226. The flip roller cam 226 is respectively located at both ends of the plurality of support plates 221. The outsides of the plurality of support plates 221 are all fixedly connected to the flip roller paper gripper row 224. The two ends of the bearing 223 are respectively connected to the cam adjustment unit 24 and the format adjustment unit 25.

[0054] The flip roller paper gripper row 224 includes a No. 1 gear block 2241, a No. 2 gear block 2242, a paper gripper shaft 2243, and a tooth pad 2244. An end plate 222 is respectively installed on the support plates 221 on both sides, and the tooth pad 2244 and the paper gripper shaft 2243 are installed between the two end plates 222. The No. 1 gear block 2241 is fixedly sleeved on both sides of the paper gripper shaft 2243. The No. 1 gear block 2241 is meshed with a rack set on one side of the flip roller cam 226 to control the opening and closing of the tooth row. A plurality of paper grippers 2245 are evenly distributed on the paper gripper shaft 2243. The paper grippers 2245 cooperate with the tooth pad 2244 to grip the paper, and the paper grippers 2245 are in contact with the tooth pad 2244 to form a paper gripping state. The working principle of the flip roller gripper row 224 is as follows: the flip roller cam 226 is fixed on the external support mechanism, the bearing 223 rotates under the drive of external force, thereby driving the support plate 221 and the flip roller gripper row 224 to rotate, and the No. 1 gear block 2241 rotates to mesh with the rack on one side of the flip roller cam 226. Since the No. 1 gear block 2241 is fixedly connected to the gripper shaft 2243, the gripper shaft 2243 moves relative to the flip roller cam 226 and drives the gripper 2245 to flip. This structure can flip more than 200 degrees, can grip the tail of the paper on the even-number flip roller 21, and flip the paper over to complete the paper flipping function, and continue to rotate and transfer it to the paper transfer roller 23. The outer side of the end plate 222 is fixedly connected to the No. 2 gear block 2242 for meshing with the paper transfer roller 23; the paper transfer roller 23 is an ordinary paper transfer roller, which only plays a role in paper transfer. In one or more embodiments, the flip roller 22 is driven to rotate by an external device, and the flip roller 22 provides driving force to the paper transfer roller 23 through the engagement of the No. 2 gear block 2242 with the paper transfer roller 23. This structure reduces one driving device, greatly reduces production costs, and saves equipment space, making the equipment more compact; one drive can drive two devices, and also avoids the error of control accuracy when using two drives, so that the paper control accuracy is higher.

[0055] The width adjustment unit 25 includes a width adjustment even-number adjustment gear 251, an intermediate gear 252, a width adjustment gear 253, a paper feed adjustment gear 254, a width locking structure 255, a width adjustment intermediate gear 256 and a width adjustment motor 257. The two ends of the bearing 223 are respectively fixedly sleeved with the width adjustment gear 253 and the flip roller driving gear 225. The flip roller driving gear 225 is meshed with the width adjustment intermediate gear 256. The width adjustment intermediate gear 256 is fixedly sleeved with the bearing 223. The width adjustment intermediate gear 256 is fixedly connected to the width adjustment intermediate gear 256. The output shaft of the motor 257 is a servo motor, and the signal of the motor 257 is connected to the controller; the outer side of the width adjustment gear 253 is provided with a width locking structure 255, and the two sides are respectively meshed with the width adjustment even-number adjustment gear 251 and the paper transfer adjustment gear 254, the paper transfer adjustment gear 254 is internally fixedly sleeved with the bearing of the paper transfer cylinder 23, and the width adjustment even-number adjustment gear 251 is internally fixedly sleeved with the even-number bearing 217, and the width locking structure 255 and the width adjustment motor 257 are respectively connected to the controller by signal. Preferably, the width locking structure 255 includes a width locking lever 2551 and a width locking cylinder 2552 fixedly connected at one end thereof, and the width locking cylinder 2552 is signal-connected to the controller.

[0056] In one or more embodiments, the width adjustment gear 253 includes an interface 2531, a housing 2532, a first width gear 2533, and a second width gear 2534, which are connected in sequence from the outside to the inside. The first width gear 2533 and the second width gear 2534 are connected by a width adjustment connector 2537. A limit block 2536 and an interface 2531 are installed inside the housing 2532. A plug-in block 2535 is installed inside the interface 2531. One end of the plug-in block 2535 cooperates with the plug-in width locking lever 2551 so that the plug-in block 2535 can be locked. Driven by the web locking lever 2551, the interface 532 moves left and right. Preferably, a spring is provided on the plug-in block 2535, and the spring is located on the side away from the web locking lever 2551; a limit block 2536 is provided at the other end of the plug-in block 2535, and the limit block 2536 can move left and right in the housing 2532 under the action of external force, and a gap is provided between the limit block 2536 and the web adjustment connector 2537; the first web gear 2533 is meshed with the web adjustment even-number adjustment gear 251, and the second web gear 2534 is meshed with the paper transfer adjustment gear 254. Preferably, the web adjustment even-number adjustment gear 251, the first web gear 2533, the second web gear 2534, and the paper transfer adjustment gear 254 are all helical gears. A scale is provided on the outside of the housing 2532, and the rotation angle of the roller can be calibrated twice. Preferably, the width adjustment gear 253 is transmission-connected to the width adjustment even-number adjustment gear 251 via the intermediate gear 252 .

[0057] The intermediate gear 252 includes a first intermediate gear 2521, a second intermediate gear 2522, a third intermediate gear 2523 and a fourth intermediate gear 2524. The first intermediate gear 2521 and the second intermediate gear 2522 are coaxially fixed, the third intermediate gear 2523 and the fourth intermediate gear 2524 are coaxially fixed, the first intermediate gear 2521 is meshed with the second width gear 2534, the second intermediate gear 2522 is meshed with the third intermediate gear 2523, the fourth intermediate gear 2524 is meshed with the even-number adjustment gear 216, and the first intermediate gear 2521 is a helical gear. The working principle of the width adjustment unit 25 is as follows: initially, the width locking lever 2551 is inserted into the interface 2531 and contacts the connector 535. The staff inputs data into the controller according to the actual width adjustment requirements. The controller controls the width adjustment motor 257 to rotate. The width adjustment motor 257 drives the flip roller 22 to rotate through the width adjustment intermediate gear 256. Since the width adjustment gear 253 is respectively engaged with the paper transfer modulation gear 54 and the width adjustment even-number adjustment gear 251, when the flip roller 22 rotates, the even-number flip roller 21 and the paper transfer roller 23 rotate at the same time. When the width adjustment motor 257 stops rotating (that is, all three rollers reach the preset position), the controller controls the width locking cylinder 2552 to actuate. The width locking cylinder 522 drives the width locking lever 2551 to press the connector 535 inward, and the connector 535 moves inward. The web adjustment gear 253 is moved sideways and drives the limit block 2536 to approach the web adjustment connecting piece 2537 until the web adjustment connecting piece 2537 is pressed, so that the web adjustment gear 253 cannot move left and right as a whole. Since the web adjustment even-number adjustment gear 251, the No. 1 web gear 2533, the No. 2 web gear 2534, the paper transfer adjustment gear 254 and the No. 1 intermediate gear 2521 are all helical gears, when the No. 1 web gear 2533 and the No. 2 web gear 2534 move toward the inside of the drum, they will drive the web adjustment even-number adjustment gear 251, the intermediate gear 252 and the paper transfer adjustment gear 254 to move toward the inside of the drum and be fixed, and cannot move along the axial direction of the drum, but can only rotate circumferentially under the drive of external force, so that the present scheme has a high degree of automation and makes the operation simple. At the same time, during the entire operation process, the position of the paper is controlled and will not move, affecting the accuracy.

[0058] When the processing of this batch of paper is completed and the next batch of paper is to be printed, the staff opens the format locking cylinder 2552 through the controller, and the format locking cylinder 2552 drives the format locking cylinder 551 to move outward. Since the plug-in block 2535 is provided with a spring, the spring overcomes the elastic force to restore the deformation, and the plug-in block 535 drives the limit block 2536 to move outward inside the housing 2532 and return to the initial position, and finally the format adjustment gear 253, the format adjustment even-number adjustment gear 251, the intermediate gear 252 and the paper transfer adjustment gear 254 can move left and right along the axis under the action of external force, and enter the next format adjustment cycle. The controller mentioned in this article is the host controller of the printing press. The working principle of the flipping part 2 is as follows: the staff first presets the paper according to the paper specifications (adjusts the position of the paper head cam 2110 through the cam adjustment unit 24, and adjusts the paper width through the width adjustment unit 25) to ensure that during the flipping process, the paper tail in the double flipping roller 1 can be accurately gripped by the paper gripper 2245. During the rotation of the double flipping roller 1, the paper head gripper 215 and the paper tail gripper 212 grip the paper head and paper tail of the paper respectively. During the rotation of the even-numbered bearing 217, the paper tail gripper 212 flattens the paper. When it reaches the junction of the double flipping roller 1 and the flipping roller 22, the flipping roller 22 grips the paper tail to flip the paper over, completing the flipping, and continues to rotate to transfer it to the paper transfer roller 23.

[0059] like Fig.14 and Fig.15 As shown, the phase adjustment mechanism 3 includes two symmetrically arranged chain tensioning units 32, and a guide rail 35 and a driving unit 36 ​​are arranged on the outer side of the chain tensioning unit 32. The guide rail 35 is used to be installed on an external device, so that the tensioning plate 322 of the chain tensioning unit 32 can reciprocate along the guide rail 35 under the drive of the adjustment unit 36, and the signal of the driving unit 36 ​​is connected to the controller; each chain tensioning unit 32 is provided with a driven paper transfer sprocket 33 above and an active paper transfer sprocket 37 below, and the three form a transmission structure, and a paper gripper row 34 and a guide plate 31 are installed between the two chain tensioning units 32. Preferably, the two symmetrical driven paper transfer sprockets 33, the two active paper transfer sprockets 37 and the two chain tensioning units 32 are fixedly connected to effectively ensure the consistency of the phases on both sides of the phase adjustment mechanism 3.

[0060] A locking limit unit 39 is provided on one side of the chain tensioning unit 32 to limit the position of the chain tensioning unit 32, and the locking limit unit 39 signal is connected to the controller. In one embodiment, the driving unit 36 ​​is respectively connected to the two chain tensioning units 32, and a guide rail 35 is provided on the outer side of one chain tensioning unit 32, and a locking limit unit 39 is provided on the outer side of the other chain tensioning unit 32 to prevent the guide rail 35 from blocking the limiting part of the locking limit unit 39, which is convenient for the production of the tensioning plate 322, and there is no need to specially set the limiting structure of the tensioning plate 322 to avoid the guide rail 35, saving process and production costs. In another embodiment, the driving unit 36 ​​is respectively connected to the two chain tensioning units 32, and a guide rail 35 and a locking limit unit 39 are provided on the outer side of any chain tensioning unit 32, which saves equipment space and reduces the floor area. The locking limit unit 39 is used to limit the chain tensioning unit 32.

[0061] A bracket 38 is provided above and below the chain tensioner 32, respectively, to ensure the stability of the chain tensioner 32, the driven paper transfer sprocket 33 and the active paper transfer sprocket 37. A limit plate 310 is provided on both sides of the driven paper transfer sprocket 33, respectively, to limit the adjustment position of the driven paper transfer sprocket 33, to ensure that the phase after adjustment by the phase adjustment mechanism 3 does not exceed the maximum set value. The limit plate 310 is installed on the bracket 38. In one embodiment, the guide plate 31 is installed between two brackets 38 that are symmetrical on the left and right. When assembling the printing press, it is convenient to install the phase adjustment mechanism 3 as a whole without installing the guide plate 31 on an external support device, which greatly reduces the difficulty of assembly and improves work efficiency. The chain tensioning unit 32 includes a tensioning chain 321, a tensioning plate 322, a driven wheel 323 and a driving wheel 324. The tensioning chain 321 is sequentially sleeved on the driven wheel 323, the driving paper conveying sprocket 37, the driving wheel 324 and the driven paper conveying sprocket 33 to form a transmission structure. The driving wheel 324 and the driven wheel 323 are fixedly connected by the tensioning plate 322. The lower part of the tensioning plate 322 is connected to the adjustment unit 36. Preferably, a plurality of limiting holes 3222 are provided on the tensioning plate 322, each limiting hole 3222 cooperates with a locking limiting unit 39 to limit the tensioning plate 322, and a connecting piece 3221 is provided at the bottom of the tensioning plate 322.

[0062] The adjustment unit 36 ​​includes an adjustment motor 361, a driving member 362 and a connecting rod. Two driving members 362 are fixedly connected to the connecting rod respectively. Each driving member 362 cooperates with a connecting member 3221 to form a transmission structure. One end of the connecting rod is fixedly connected to the adjustment motor 361. The signal of the adjustment motor 361 is connected to the controller. The staff controls the rotation of the adjustment motor 361 through the controller. The adjustment motor 361 controls the driving member 362 and the rack 221 to move, thereby driving the tensioning plate 322 to move left and right, and finally driving the chain tensioning unit 32 to move accurately, thereby changing the phase of the driven paper conveying sprocket 33. The adjustment motor 361 is preferably a servo motor. In one embodiment, the driving member 362 cooperates with a connecting member 3221 in the form of a gear and a rack, that is, the driving member 362 is a gear and the connecting member 3221 is a rack. In another embodiment, the driving member 362 cooperates with a connecting member 3221 in the form of a lead screw and a nut, that is, the driving member 362 is a lead screw and the connecting member 3221 is a nut. A bracket 38 is provided above and below the driven wheel 323 .

[0063] The locking and limiting unit 39 includes a limiting rod 391, a locking cylinder 392 and a locking lever 393. The locking cylinder 392 is connected to the limiting rod 391 through the locking lever 393. The limiting rod 391 is used to insert into the limiting hole 3222 to limit the tensioning plate 322. The locking cylinder 392 signal is connected to the controller. The locking cylinder 392 is installed on the external support device.

[0064] The working principle of the phase adjustment mechanism 3 is as follows: the active paper transfer sprocket 37 is connected to the main machine and is stationary, the guide rail 35 and the locking cylinder 392 are fixedly mounted on the main machine or an external supporting device, and the staff inputs the paper width parameters into the controller, and the controller controls the adjustment motor 361 to rotate to the set number of revolutions according to the set program, and the adjustment motor 361 drives the tensioning plate 322 to move accurately to the set position, and the tensioning plate 322 moves to drive the driven paper transfer sprocket 33 to rotate through the tensioning chain 321, thereby completing the phase adjustment; after the controller determines that the adjustment motor 361 stops working, it controls the locking cylinder 392 to work, and since the locking cylinder 392 is mounted on the main machine or an external supporting device, the locking cylinder 392 drives the limit rod 391 to be inserted into the edge of one side of the limit hole 3222 through the locking lever 393, and the tensioning plate 322 is locked and limited. The phase adjustment mechanism 3 can be used for adjusting the format of an inkjet digital printing machine. According to the difference in the format adjustment, the corresponding chain phase is changed through the adjustment motor 361 of the mechanism, so that the relative position of the closed-loop paper path of the entire digital printing machine remains unchanged, thereby ensuring the accuracy of paper transmission.

[0065] The controller that appears in this solution is the host controller of the device.

[0066] The principle of single-sheet double-sided inkjet printer is:

[0067] like Figure 2 and Figure 3 As shown, the printing cylinder 1 is located below the aqueous inkjet system 5, the printing cylinder 1, the single-diameter paper transfer cylinder 42 and the even-number paper transfer cylinder 41 are arranged in sequence, and the axes of the three are arranged in a colinear manner. The even-number paper transfer cylinder 41 receives new paper from the paper pile 72 through the paper feed shaft 71 of the paper feed part 7; the right side of the printing cylinder 1 is provided with a phase adjustment mechanism 3, and the phase adjustment mechanism 3 is located below the paper transfer part 4, the flip end of the printing cylinder 1 is tangent to the even-number flip cylinder 21, the paper transfer cylinder 23 is located below the active paper transfer sprocket 37, the left side of the printing cylinder 1 is close to the paper receiving cylinder 61 of the paper receiving part 6, and the paper receiving cylinder 61 transfers the printed paper to the paper receiving pile 63 through the paper receiving tensioning sprocket 62, and the position of the paper after the first printing of the printing cylinder 1, the position before the flip part 2, and the position of the paper receiving cylinder 61 are all provided with a drying lamp group 64 for drying the ink on the printed paper. The outer side of the printing cylinder 1 is also tangent to the paper pressing wheel 8, and the paper pressing wheel 8 is located between the paper transfer part 4 and the underwater inkjet system 5.

[0068] The working principle of single-sheet double-sided inkjet printer is:

[0069] The platform of this single-sheet inkjet digital printing machine adopts a roller type, and the paper is transferred from one roller to the next roller through roller transmission and handover. The handover process is that when the tooth rows of two adjacent rollers rotate to the center line of the two rollers, the paper gripper row of the roller holding the paper opens and releases the paper. At the same time, the paper gripper row on the other roller closes, holds the paper and continues to rotate. The paper is transferred from one roller to another roller to complete the handover and transfer; the staff adjusts and confirms the number of paper transfer rollers in the paper transfer part 4 according to the length of the paper, and controls the phase adjustment mechanism 3 to automatically adjust to the corresponding position through the controller according to the size and specifications of the paper, so as to ensure that the entire closed paper path cycle remains unchanged; when single-sided printing is required, the staff adjusts the function-related parameters, and the paper feed shaft 71 transfers the paper from the paper pile 72 to the even-numbered paper transfer roller 41, and the paper is transferred to the printing roller 1 through the single-diameter paper transfer roller 42, and the water After the water-based inkjet system 5 is printed, it is directly transferred to the paper receiving part 6. The function of the paper receiving part 6 is to transfer and collect the printed paper, and it is not in the printing closed paper path; when double-sided printing is required, the staff adjusts the function-related parameters, and the paper feed shaft 71 transfers the paper from the paper pile 72 to the even-numbered paper transfer cylinder 41, and the paper is transferred to the printing cylinder 1 through the single-diameter paper transfer cylinder 42. After the first page is printed by the water-based inkjet system 5, the paper continues to rotate with the printing cylinder 1 and transfers the paper to the even-numbered flipping cylinder 21. The paper flips in the flipping part 2, and then passes through the phase adjustment mechanism 3 and transfers it to the even-numbered paper transfer cylinder 41 again. The paper is transferred to the printing cylinder 1 through the single-diameter paper transfer cylinder 42. After the second page is printed by the water-based inkjet system 5, it is directly transferred to the paper receiving part 6. The function of the paper receiving part 6 is to transfer and collect the printed paper, and it is not in the printing closed paper path. This scheme adopts the roller method and cooperates with the advanced flipping mechanism to achieve double-sided printing and ensure printing accuracy and printing quality. It solves the drawbacks of web-fed inkjet digital printing presses, such as single paper type and inflexible use.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A sheet-fed double-sided inkjet printer, comprising a water-based inkjet system arranged above a printing cylinder and a paper receiving part arranged on one side, characterized in that: The other side of the printing cylinder is respectively provided with a paper conveying part for conveying paper, a turning part for turning over paper, and a phase adjustment mechanism for adjusting the phase of paper. The phase adjustment mechanism includes two chain tensioning units. A guide rail and a driving unit are provided on the outer side of the chain tensioning unit. The guide rail is used to be installed on an external device. The driving unit signal is connected to the controller so that the tensioning plate of the chain tensioning unit can reciprocate along the guide rail under the drive of the adjustment unit. A paper gripper row and a guide plate are installed between the two chain tensioning units, and the paper conveying part and the turning part are respectively located at the upper and lower ends of the phase adjustment mechanism. A single-sided paper gripping mechanism and a double-sided paper gripping mechanism are staggered on the outer wall of the printing cylinder. A single-sided cam and a double-sided cam are provided at one end of the printing cylinder. The double-sided cam is connected to the cylinder, and the cylinder signal is connected to the controller; when single-sided printing is required, the single-sided paper gripping mechanism and the double-sided paper gripping mechanism both cooperate with the single-sided cam to grip the paper; when double-sided printing is required, only the double-sided paper gripping mechanism cooperates with the double-sided cam to grip the paper, so as to realize double-sided switching of a single sheet of paper; A single-diameter paper transfer roller and an even-diameter paper transfer roller are respectively provided on one side of the printing cylinder; the flipping part includes a format adjustment unit and an even-diameter flipping roller, a flipping roller and a paper transfer roller which are arranged in parallel on one side thereof; a cam adjustment unit for adjusting the paper head cam is installed on one side of the even-diameter flipping roller; the format adjustment unit includes a format adjustment even-diameter adjustment gear, a format adjustment gear, a paper transfer adjustment gear, a format locking structure and a format adjustment motor.

2. The sheet-fed double-sided inkjet printer according to claim 1, characterized in that: The even-numbered paper transfer roller is located above the driven paper transfer sprocket of the phase adjustment mechanism, and the active paper transfer sprocket of the phase adjustment mechanism is located above the paper transfer roller of the turning part.

3. The sheet-fed double-sided inkjet printer according to claim 1, characterized in that: The printing roller is provided with a paper tail adsorption device, and the paper tail adsorption device is provided with a suction seat for adsorbing paper. The upper surface of the suction seat is tangent to the diameter of the roller, and the two can move relatively along the circumference of the roller.

4. The sheet-fed double-sided inkjet printer according to claim 1, characterized in that: The format adjustment unit is used to adjust the format of the paper, and the format adjustment unit and the cam adjustment unit are respectively connected to the controller by signals.

5. The sheet-fed double-sided inkjet printer according to claim 4, characterized in that: The cam adjustment unit includes a driving gear and a cam locking structure for limiting the driving gear. The cam adjustment motor and the paper head cam are fixedly connected to both sides of the driving gear. The cam adjustment motor and the cam locking structure are respectively connected to the controller by signals.

6. The sheet-fed double-sided inkjet printer according to claim 4, characterized in that: The two ends of the bearing of the flipping roller are respectively fixedly sleeved with the width adjustment gear and the flipping roller driving gear, the flipping roller driving gear is fixedly connected to the width adjustment motor, the outer side of the width adjustment gear is provided with a width locking structure, and the two sides are respectively meshed with the width adjustment even-number adjustment gear and the paper transfer adjustment gear, the inside of the paper transfer adjustment gear is fixedly sleeved with the bearing of the paper transfer roller, the inside of the width adjustment even-number adjustment gear is fixedly sleeved with the bearing of the even-number flipping roller, and the signals of the width locking structure and the width adjustment motor are respectively connected to the controller.

7. The sheet-fed double-sided inkjet printer according to claim 1, characterized in that: A driven paper conveying sprocket and an active paper conveying sprocket are respectively arranged at the upper and lower ends of each chain tensioning unit, and the three form a transmission structure.

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