Paper rubbing device and printing system

Abstract

The utility model relates to a paper rubbing device and a printing system. The paper twisting device comprises a base rack, a bottom plate, a hoisting beam frame, a rotating shaft, a paper twisting wheel, a paper pressing assembly, a height limiting assembly and a lifting driving mechanism. The bottom plate is mounted on the base rack through the lifting driving mechanism; the hoisting beam frame is mounted on the base rack; the height limiting assembly is installed on the hoisting beam frame and used for detecting the height position of the top face of a paper pile. The rotating shaft is mounted on the base rack; the at least two pickup rollers are respectively fastened and connected to the rotating shaft in a sleeving manner; the paper pressing assembly is mounted on the hoisting beam frame and is vertically arranged; the bottommost end of the paper pressing assembly is flush with or lower than the lowest point of the stroke of the paper twisting wheel. And the rotating shaft is connected with the driving motor through a belt. The paper rubbing device has the advantage of being more stable in paperboard conveying.

Description

Technical Field

[0001] The present application relates to the technical field of cardboard processing, and in particular to a paper rubbing device and a printing system. Background Art

[0002] Corrugated paper boxes are logistics packaging containers that integrate transportation and sales functions. Consumers are constantly putting forward new requirements for the appearance, environmental protection and function of product packaging, which has led the paper box industry to continuously innovate technology to meet the comprehensive requirements of the terminal market for external packaging quality and cost.

[0003] In the field of automatic cardboard printing technology, there are two main ways of conveying cardboard piece by piece in the prior art. One is to manually place the cardboard and then convey and print it one by one, and the other is to use automatic paper feeding equipment.

[0004] In the existing automatic paper feeding equipment, for the paper rubbing device, its single-wheel paper rubbing may cause the paperboard to be offset and tilted during transportation, which is not conducive to subsequent processing.

[0005] Especially when the cardboard is deformed, such as tilted corners or curved, when the existing paper rubbing equipment is used to convey the cardboard one by one, the friction force of the paper rubbing will be insufficient and the stability and continuity of the paper rubbing cannot be guaranteed, and the cardboard may even be conveyed in a tilted state. Utility Model Content

[0006] Based on this, the purpose of the present application is to provide a paper picking device, which has the advantage of ensuring stable conveyance of the paperboard even if the paperboard is deformed.

[0007] In one aspect of the present application, a paper picking device is provided, including a base frame, a bottom plate, a hoisting beam frame, a rotating shaft, a paper picking wheel, a paper pressing assembly, a height limiting assembly, and a lifting drive mechanism;

[0008] The bottom plate is mounted on the base frame through the lifting drive mechanism;

[0009] The hoisting beam frame is installed on the base frame;

[0010] The height limiting assembly is installed on the hoisting beam frame and is used to detect the height position of the top surface of the paper stack;

[0011] The rotating shaft is mounted on the base frame; at least two pickup wheels are respectively and firmly sleeved on the rotating shaft; the paper pressing assembly is mounted on the hanging beam frame and is arranged vertically;

[0012] The bottom end of the paper pressing assembly is flush with or lower than the lowest point of the travel of the pickup wheel;

[0013] The rotating shaft is connected to the driving motor through a belt.

[0014] Compared with the prior art, the paper rubbing device described in the present application is provided with a paper pressing assembly and a height limiting assembly, so that the cardboard is flattened when it is in the highest position, so as to ensure that the cardboard is in a flat state for paper rubbing and conveying, which not only ensures that the flat cardboard can be sent out by the rubbing wheel, but also can make the cardboard with deformation such as bending or warping become flat, so that it can be sent out by the rubbing wheel in a better state. Since the bottom end of the paper pressing assembly is flush with the lowest point of the stroke of the rubbing wheel, when the straight section of the rubbing wheel faces downward, there is a certain distance between the straight section of the rubbing wheel and the cardboard, so that when the two rubbing wheels rotate at the same time, the end of the straight section of the rubbing wheel contacts the cardboard, and then the starting point of the contact between the two rubbing wheels and the cardboard is unified, thereby ensuring the synchronization of the contact between the two rubbing wheels and the cardboard, and finally ensuring the smooth delivery of the cardboard, and the end face of the cardboard is always parallel to the rotating shaft, so that the cardboard will not be skewed. Therefore, the paper rubbing device of the present application is not only suitable for the one-by-one delivery of flat cardboards, but also suitable for the one-by-one delivery of deformed cardboards.

[0015] Furthermore, the paper pressing assembly and the paper pickup wheel are matched one by one;

[0016] The two paper pressing assemblies are respectively located on the same side of the paper pickup wheel, or the two paper pressing assemblies are respectively located on different sides of the paper pickup wheel.

[0017] Furthermore, the pickup wheel comprises a wheel body and a strip-shaped resistance band;

[0018] The cross section of the wheel body is arcuate;

[0019] The outer side surface of the pickup wheel is respectively formed with a flat surface segment and a curved surface segment;

[0020] A groove is formed in the middle of the plane section of the pickup wheel;

[0021] The two ends of the resistance band are respectively fixedly mounted on the two ends of the groove, and the resistance band is closely attached to the outer wall of the arc surface segment;

[0022] The resistance band is wrapped around the outer side of the wheel body in a C shape.

[0023] Furthermore, the paper pressing assembly comprises a paper pressing support and a paper pressing wheel, the paper pressing wheel is rotatably connected to the paper pressing support, and the paper pressing support is installed on the hanging beam frame;

[0024] The rotation axis of the paper pressing wheel is parallel to the rotation axis of the rotating shaft;

[0025] The lowest point of the stroke of the paper pressing wheel is flush with or lower than the lowest point of the stroke of the paper picking wheel.

[0026] Furthermore, a first sensing piece in the shape of "Z" is provided on the side wall of the pickup wheel, a first mounting piece is installed on the bottom surface of the hanging beam, and a first sensing switch is installed on the bottom surface of the first mounting piece;

[0027] The first induction switch is used to detect a passing signal of the first induction sheet.

[0028] Furthermore, the cross section of the bottom plate is arc-shaped, or the bottom plate is placed obliquely.

[0029] Furthermore, the height limiting assembly includes a distance sensor, which is installed on the hoisting beam and is used to detect the height position of the top surface of the paper stack.

[0030] Furthermore, the height limiting assembly includes a cylinder, a pressure plate, a vertical plate, a second sensing sheet, a second mounting sheet, and a second sensing switch;

[0031] The cylinder is arranged vertically and its top is mounted on the hanging beam frame;

[0032] The pressure plate is mounted on the end of the piston rod of the cylinder and is placed below the cylinder;

[0033] The vertical plate is fixed on the upper surface of the pressing plate;

[0034] The second sensing sheet is mounted on the vertical plate; the second mounting sheet is mounted on the outer side of the cylinder; the second sensing switch is mounted on the second mounting sheet; the second sensing switch is used to detect the passing signal of the second sensing sheet.

[0035] Furthermore, the lifting drive mechanism includes a lifting motor, a synchronous belt, and a screw assembly; the four screw assemblies are respectively mounted on the base frame and connected by the synchronous belt;

[0036] The screw assembly includes an upper connecting block, an intermediate connecting block, a lower connecting block, a shaft sleeve, a screw sleeve, and a screw shaft;

[0037] The intermediate connecting block is movably sleeved on the screw shaft and mounted on the base frame;

[0038] The lower connecting block is rotatably sleeved on the bottom end of the screw shaft and mounted on the base frame;

[0039] The screw sleeve is sleeved on the screw shaft and is located above the screw shaft;

[0040] The upper connecting block is fixed to the top end of the screw sleeve;

[0041] The shaft sleeve is sleeved on the screw shaft and is fastened to the screw shaft via a pin;

[0042] The synchronous belt is wound around the shaft sleeve; the lifting motor is rotatably connected to the bottom end of one of the screw shafts.

[0043] Furthermore, it also includes side baffles and limit baffles;

[0044] The side baffle is installed on the side of the bottom plate and is used to limit the side position of the paper stack;

[0045] The limit baffle is installed on the side of the base frame and is located in the forward direction of the paper stack, and is used to limit the front side of the paper stack.

[0046] Another aspect of the present application provides a paperboard printing system, comprising the paper rubbing device and the conveying printing device described in any of the above schemes;

[0047] The conveying and printing device is installed at one side of the paper pickup device, and is used to receive and print the paperboard of the paper pickup device.

[0048] For better understanding and implementation, the present application is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The three-dimensional structure of the paper picking device of the present application is schematically shown;

[0050] Figure 2 A front view of an exemplary paper picking device of the present application;

[0051] Figure 3 The three-dimensional structure of the exemplary paper pickup wheel (and the first sensing sheet, the first mounting sheet, and the first sensing switch) of the present application is schematically shown;

[0052] Figure 4 A front view of an exemplary pickup wheel of the present application;

[0053] Figure 5 The three-dimensional structure of the exemplary paper pressing assembly of the present application is shown;

[0054] Figure 6 A schematic diagram of the assembly relationship between the pickup wheel and the paper pressing assembly of the present application;

[0055] Figure 7 The three-dimensional structure diagram of an exemplary height limiting assembly of the present application is shown;

[0056] Figure 8 The three-dimensional structure diagram of an exemplary lifting drive mechanism (excluding a synchronous belt) of the present application. DETAILED DESCRIPTION

[0057] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating positions or positional relationships, are based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, unless otherwise specified, "multiple" means two or more.

[0058] See also Figure 1-Figure 8 An exemplary paper pickup device of the present application includes a base frame 10, a bottom plate 20, a hanging beam frame 30, a rotating shaft 40, a paper pickup wheel 50, a paper pressing assembly 60, a height limiting assembly 70, and a lifting drive mechanism 80;

[0059] The bottom plate 20 is mounted on the base frame 10 through the lifting drive mechanism 80;

[0060] The hoisting beam frame 30 is installed on the base frame 10;

[0061] The height limiting assembly 70 is installed on the hoisting beam frame 30 and is used to detect the height position of the top surface of the paper stack;

[0062] The rotating shaft 40 is mounted on the base frame 10; at least two pickup rollers 50 are respectively fastened and sleeved on the rotating shaft 40; the paper pressing assembly 60 is mounted on the hanging beam frame 30 and is arranged vertically;

[0063] The bottom end of the paper pressing assembly 60 is flush with or lower than the lowest point of the travel of the pickup wheel 50;

[0064] The rotating shaft 40 is connected to the driving motor 41 via a belt.

[0065] Compared with the prior art, by providing the paper pressing assembly 60 and the height limiting assembly 70, the cardboard is flattened when it is at the highest position, so as to ensure that the cardboard is in a flat state for paper feeding, which not only ensures that the flat cardboard can be sent out by the paper feeding wheel 50, but also makes the cardboard with deformation such as bending or warping become flat, so that it can be sent out by the paper feeding wheel 50 in a better state. Since the bottom end of the paper pressing assembly 60 is flush with the lowest point of the stroke of the paper feeding wheel 50, when the straight section of the paper feeding wheel 50 faces downward, there is a certain distance between the straight section of the paper feeding wheel 50 and the cardboard, so that when the two paper feeding wheels 50 rotate at the same time, the end of the straight section of the paper feeding wheel 50 contacts the cardboard, and then the starting point of the two paper feeding wheels 50 contacting the cardboard is unified, thereby ensuring the synchronization of the contact between the two paper feeding wheels 50 and the cardboard, and finally ensuring the smooth feeding of the cardboard, and the end surface of the cardboard is always parallel to the rotating shaft 40, so that the cardboard will not be skewed. Therefore, the paper picking device of the present application is not only suitable for sending out flat paperboards one by one, but also suitable for sending out deformed paperboards one by one.

[0066] In some preferred embodiments, the paper pressing assembly 60 is matched with the paper pickup wheel 50 in a one-to-one correspondence;

[0067] The two paper pressing assemblies 60 are respectively located on the same side of the pickup roller 50, or the two paper pressing assemblies 60 are respectively located on the opposite sides of the pickup roller 50. The opposite sides described here are divided into two situations, one is that the two paper pressing assemblies 60 are located between the two pickup rollers 50, and are arranged facing each other; the other is that the two paper pressing assemblies 60 are located outside the two pickup rollers 50, and are arranged back to back. Therefore, there are at least three positional relationships between the paper pressing assemblies 60 and the pickup rollers 50 of the present application: 1) the paper pressing assemblies 60 are all located on the same side of the corresponding pickup rollers 50; 2) the two paper pressing assemblies 60 are located between the two pickup rollers 50; 3) the two paper pressing assemblies 60 are located outside the two pickup rollers 50.

[0068] In some preferred embodiments, the pickup wheel 50 includes a wheel body 51 and a strip-shaped resistance band 52;

[0069] The cross section of the wheel body 51 is arcuate;

[0070] The outer side surface of the pickup wheel 50 is respectively formed with a flat surface segment and a curved surface segment;

[0071] A groove (not marked in the figure) is formed in the middle of the plane section of the pickup wheel 50;

[0072] The two ends of the resistance band 52 are respectively fixedly mounted on the two ends of the groove, and the resistance band 52 is closely attached to the outer wall of the arc surface segment;

[0073] The resistance band 52 is wrapped around the outer side of the wheel body 51 in a C shape.

[0074] Furthermore, the material of the resistance band 52 can be plastic, rubber, foam plastic, metal (frosted surface), etc.

[0075] Since the resistance band 52 is in a "C" shape, the resistance band 52 of the paper pickup wheel 50 has an obvious starting point and an end point, so as to facilitate more concentrated force for paper pickup.

[0076] In some preferred embodiments, the paper pressing assembly 60 includes a paper pressing support 61 and a paper pressing wheel 62, the paper pressing wheel 62 is rotatably connected to the paper pressing support 61, and the paper pressing support 61 is installed on the hanging beam frame 30;

[0077] The rotation axis of the paper pressing wheel 62 is parallel to the rotation axis of the rotating shaft 40;

[0078] The lowest point of the travel of the paper pressing wheel 62 is flush with the lowest point of the travel of the paper picking wheel 50 , or the lowest point of the travel of the paper pressing wheel 62 is lower than the lowest point of the travel of the paper picking wheel 50 .

[0079] The lowest point of the stroke of the paper pressing wheel 62 is always constant, which is the lowest point of the outer circumference of the paper pressing wheel 62; and since the pickup wheel has an arcuate cross-sectional structure, the lowest point of the stroke of the pickup wheel 50 is the lowest point of the outer circumference when the arc segment faces downward.

[0080] Figure 6 In the state shown, the straight section of the paper pickup wheel 50 faces downward, and what is shown at this time is the relative position relationship between the paper pickup wheel and the paper pressure wheel, so as to illustrate that when the straight section faces downward, this is not the lowest point of the paper pickup wheel. The lowest point of the paper pressure wheel at this time is shown to be lower than the height position of the straight section of the paper pickup wheel.

[0081] In some preferred embodiments, a first "Z"-shaped sensing sheet 53 is provided on the side wall of the pickup wheel 50, a first mounting sheet 54 is installed on the bottom surface of the hanging beam 30, and a first sensing switch 55 is installed on the bottom surface of the first mounting sheet 54;

[0082] The first induction switch 55 is used to detect the passing signal of the first induction sheet 53 .

[0083] In some preferred embodiments, the bottom plate 20 has an arc-shaped cross section, or the bottom plate 20 is placed obliquely. When placed obliquely, the bottom plate 20 moves in a downward direction, that is, the side of the bottom plate 20 close to the limit baffle 11 faces downward; when the bottom plate 20 is arc-shaped, the middle part of the bottom plate 20 is convex upward. Such a structural form is conducive to the cardboard being conveyed forward, and the gravity promotes the forward movement, and the transportation is more labor-saving.

[0084] In some preferred embodiments, the height limiting assembly 70 includes a distance sensor, which is installed on the hanging beam frame 30 and is used to detect the height position of the top surface of the paper stack.

[0085] In some other preferred embodiments, the height limiting assembly 70 includes a cylinder 71, a pressing plate 72, a vertical plate 73, a second sensing sheet 74, a second mounting sheet 75, and a second sensing switch 76;

[0086] The cylinder 71 is arranged vertically and its top is mounted on the hanging beam frame 30;

[0087] The pressure plate 72 is mounted on the end of the piston rod of the cylinder 71 and is placed below the cylinder 71;

[0088] The vertical plate 73 is fixed on the upper surface of the pressing plate 72;

[0089] The second sensing sheet 74 is mounted on the vertical plate 73 ; the second mounting sheet 75 is mounted on the outer side of the cylinder 71 ; the second sensing switch 76 is mounted on the second mounting sheet 75 ; the second sensing switch 76 is used to detect the passing signal of the second sensing sheet 74 .

[0090] In the present application, the first induction switch 55 and the second induction switch 76 are photoelectric induction switches or contact switches respectively.

[0091] In some preferred embodiments, the lifting drive mechanism 80 includes a lifting motor 81, a synchronous belt 82, and a screw assembly; four screw assemblies are respectively mounted on the base frame 10 and connected by the synchronous belt 82;

[0092] The screw assembly includes an upper connecting block 88, an intermediate connecting block 86, a lower connecting block 84, a sleeve 85, a screw sleeve 87, and a screw shaft 83;

[0093] The intermediate connecting block 86 is movably sleeved on the screw shaft 83 and mounted on the base frame 10;

[0094] The lower connecting block 84 is rotatably sleeved on the bottom end of the screw shaft 83 and mounted on the base frame 10;

[0095] The screw sleeve 87 is sleeved on the screw shaft 83 and is located above the screw shaft 83;

[0096] The upper connecting block 88 is fixed to the top end of the screw sleeve 87;

[0097] The shaft sleeve 85 is sleeved on the screw shaft 83 and is fastened to the screw shaft 83 via a pin;

[0098] The synchronous belt 82 is wound around the shaft sleeve 85 ; the lifting motor 81 is rotatably connected to the bottom end of one of the screw shafts 83 .

[0099] In some preferred embodiments, it further includes a side baffle 21 and a limit baffle 11;

[0100] The side baffle is installed on the side of the bottom plate 20 to limit the side position of the paper stack;

[0101] The limiting baffle 11 is installed on the side of the base frame 10 and is located in the forward direction of the paper stack, and is used to limit the front side of the paper stack.

[0102] An exemplary cardboard printing system of the present application includes the paper rubbing device and the conveying printing device described in any of the above schemes;

[0103] The conveying and printing device is installed at one side of the paper pickup device, and is used to receive and print the paperboard of the paper pickup device.

[0104] Working principle of the cardboard printing system of this application:

[0105] The lifting drive mechanism 80 pushes the bottom plate to rise, and the bottom plate 20 rises while driving the paper stack to rise. When the upper surface of the paper stack abuts against the height limit component, the height of the paper stack is determined by detecting the pressure value. There are two ways to detect the pressure value. One is to judge by the change of the air pressure value of the cylinder. When the air pressure value of the cylinder rises and exceeds the set threshold, it means that the pressure value is too large. At this time, the height limit component stops working. For the technical solution using the cylinder, the air pressure in the cylinder is relieved or negative pressure is generated; and the height of the bottom plate 20 is stopped at the same time. The other is to set a pressure sensor on the bottom surface of the pressure plate 72 connected to the cylinder. When the pressure value exceeds the set threshold, the cylinder is relieved or negative pressure is formed, and the bottom plate 20 is stopped from being lifted.

[0106] When the paper stack is lifted into place, the paper stack is pressed down by the paper pressing assembly, so that the top surface of the paper stack is in a flat state.

[0107] Then the rotating shaft rotates under the drive of the motor, so that at least two paper picking wheels simultaneously perform a "paper picking" action on the upper surface of the paperboard to send the paperboard out.

[0108] When the pickup wheel rotates, since the first induction switch is provided, each time the pickup wheel rotates one circle, the passing signal of the first induction sheet 53 will be detected by the first induction switch 55, thereby accurately controlling the operation of the driving motor 41.

[0109] Usually, the rotation of the pickup wheel is intermittent, and it rotates one circle, stops for a time interval, and then runs again to send out one cardboard, but two cardboards can be sent out at the same time.

[0110] In addition, in order to ensure accurate control of the rotation of the driving motor 41, an encoder is connected to the output shaft of the driving motor.

[0111] When the topmost cardboard is sent out, it is taken over by the conveying and printing device and continues to be conveyed, so as to complete the transportation and printing of a cardboard. After the printing is completed, the cylinder of the height limit assembly is in positive pressure, the pressing plate 72 descends under the pressure of the cylinder, and the lifting drive mechanism 80 continues to push the bottom plate 20 up, and then repeats the above actions to complete the paper picking, conveying and printing of another cardboard, and this cycle is repeated until the printing of the entire paper stack is completed.

[0112] In order to ensure the full automation of the process, an infrared detection sensor is also provided to detect whether there is still paper on the bottom plate. The technical solution can be realized by existing technology.

[0113] The cardboard printing system of the present application has a simplified structure, requires fewer motors, consumes less energy, greatly reduces costs, and is suitable for cardboards of more shapes and has a wide range of applications.

[0114] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A paper rubbing device, characterized in that: It includes a base frame, a bottom plate, a hoisting beam frame, a rotating shaft, a paper pickup wheel, a paper pressing assembly, a height limiting assembly, and a lifting drive mechanism; The bottom plate is mounted on the base frame through the lifting drive mechanism; The hoisting beam frame is installed on the base frame; The height limiting assembly is installed on the hoisting beam frame and is used to detect the height position of the top surface of the paper stack; The rotating shaft is mounted on the base frame; at least two pickup wheels are respectively and firmly sleeved on the rotating shaft; the paper pressing assembly is mounted on the hanging beam frame and is arranged vertically; The bottom end of the paper pressing assembly is flush with or lower than the lowest point of the travel of the pickup wheel; The rotating shaft is connected to the driving motor through a belt.

2. The paper picking device according to claim 1, characterized in that: The paper pressing assembly is matched with the paper pickup wheel in a one-to-one correspondence; The two paper pressing assemblies are respectively located on the same side of the paper pickup wheel, or the two paper pressing assemblies are respectively located on different sides of the paper pickup wheel.

3. The paper picking device according to claim 1, characterized in that: The pickup wheel comprises a wheel body and a strip-shaped resistance band; The cross section of the wheel body is arcuate; The outer side surface of the pickup wheel is respectively formed with a flat surface segment and a curved surface segment; A groove is formed in the middle of the plane section of the pickup wheel; The two ends of the resistance band are respectively fixedly mounted on the two ends of the groove, and the resistance band is closely attached to the outer wall of the arc surface segment; The resistance band is wrapped around the outer side of the wheel body in a C shape.

4. The paper picking device according to claim 2, characterized in that: The paper pressing assembly comprises a paper pressing support and a paper pressing wheel, wherein the paper pressing wheel is rotatably connected to the paper pressing support, and the paper pressing support is installed on the hanging beam frame; The rotation axis of the paper pressing wheel is parallel to the rotation axis of the rotating shaft; The lowest point of the stroke of the paper pressing wheel is flush with or lower than the lowest point of the stroke of the paper picking wheel.

5. The paper picking device according to claim 2, characterized in that: A "Z"-shaped first sensing sheet is disposed on the side wall of the pickup wheel, a first mounting sheet is mounted on the bottom surface of the hoisting beam, and a first sensing switch is mounted on the bottom surface of the first mounting sheet; The first induction switch is used to detect a passing signal of the first induction sheet.

6. The paper picking device according to any one of claims 1 to 5, characterized in that: The cross section of the bottom plate is arc-shaped, or the bottom plate is placed obliquely.

7. The paper picking device according to any one of claims 1 to 5, characterized in that: The height limiting assembly includes a cylinder, a pressing plate, a vertical plate, a second sensing sheet, a second mounting sheet, and a second sensing switch; The cylinder is arranged vertically and its top is mounted on the hanging beam frame; The pressure plate is mounted on the end of the piston rod of the cylinder and is placed below the cylinder; The vertical plate is fixed on the upper surface of the pressing plate; The second sensing sheet is mounted on the vertical plate; the second mounting sheet is mounted on the outer side of the cylinder; the second sensing switch is mounted on the second mounting sheet; the second sensing switch is used to detect the passing signal of the second sensing sheet.

8. The paper picking device according to claim 7, characterized in that: The lifting drive mechanism includes a lifting motor, a synchronous belt, and a screw assembly; the four screw assemblies are respectively mounted on the base frame and connected by the synchronous belt; The screw assembly includes an upper connecting block, an intermediate connecting block, a lower connecting block, a sleeve, a screw sleeve, and a screw shaft; The intermediate connecting block is movably sleeved on the screw shaft and mounted on the base frame; The lower connecting block is rotatably sleeved on the bottom end of the screw shaft and mounted on the base frame; The screw sleeve is sleeved on the screw shaft and is located above the screw shaft; The upper connecting block is fixed to the top end of the screw sleeve; The shaft sleeve is sleeved on the screw shaft and is fastened to the screw shaft via a pin; The synchronous belt is wound around the shaft sleeve; the lifting motor is rotatably connected to the bottom end of one of the screw shafts.

9. The paper picking device according to claim 7, characterized in that: Also includes side baffles and limit baffles; The side baffle is installed on the side of the bottom plate and is used to limit the side position of the paper stack; The limit baffle is installed on the side of the base frame and is located in the forward direction of the paper stack, and is used to limit the front side of the paper stack.

10. A cardboard printing system, characterized in that: It comprises the paper picking device and the conveying printing device according to any one of claims 1 to 9; The conveying and printing device is installed at one side of the paper picking device, and is used for receiving and printing the paperboard conveyed by the paper picking device.

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