Printing cylinder turnover mechanism of sheet-fed ink-jet printer

Abstract

The invention discloses a printing cylinder turnover mechanism of a sheet-fed ink-jet printer, which relates to the technical field of printing equipment and comprises a breadth adjusting component, an even-number-fold turnover cylinder, a turnover cylinder, a paper conveying cylinder, a cam adjusting unit and a controller. Through the combined application of the even-number-multiple overturning rollers and the overturning rollers, the precision and efficiency of double-face printing are remarkably improved, the even-number-multiple overturning rollers are driven through precisely-designed gears, the rotating speed ratio is achieved, precise overturning of paper in the double-face printing process is ensured, a driven gear is connected with a controller through a phase synchronizer, and therefore the double-face printing precision is improved. Precise control over the overturning angle is achieved, paper gripping teeth and vacuum adsorption holes are formed in the surface of the overturning roller, and a rotating air valve is arranged in the overturning roller, so that stable conveying and accurate positioning of paper in the overturning process are guaranteed, and deviation and damage of the paper in the overturning process are effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of printing equipment, and particularly to a printing drum flipping mechanism for a single-sheet inkjet printer. Background Art

[0002] Single-sheet inkjet printers are widely used in the printing industry, mainly for inkjet printing of materials such as labels and packaging. With the diversification of printing requirements and the improvement of high-efficiency requirements, the flipping mechanism of the printing drum has become one of the key technologies. At present, most common single-sheet inkjet printers on the market adopt mechanical or pneumatic flipping mechanisms, but these technologies have certain limitations in high-speed printing and precise positioning.

[0003] The traditional printing drum flipping mechanism of single-sheet inkjet printers has many deficiencies. The adjustment of the printing format mostly relies on simple mechanical structures, with low precision and slow adjustment, making it difficult to meet the requirements of rapid and precise adjustment. During double-sided printing, the flipping precision is poor. Due to the lack of precise transmission and control systems, the flipping angle error is large and the stability is poor, easily resulting in misalignment during double-sided printing. In the paper transfer link, the anti-slip performance of the traditional paper transfer drum is not good, and the paper is prone to sliding and offset. Moreover, the opening and closing timing and pressure control precision of the grippers on the flipping drum are low and the response is slow, unable to adapt to high-speed printing, affecting the printing precision and efficiency. Therefore, a printing drum flipping mechanism for a single-sheet inkjet printer is proposed to solve the above-mentioned problems. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies existing in the prior art, and propose a printing drum flipping mechanism for a single-sheet inkjet printer to solve the problems of low precision, slow adjustment, large flipping error, poor anti-slip performance, and insufficient control response in aspects such as format adjustment, double-sided printing flipping precision, and paper transfer stability of the traditional printing drum flipping mechanism of single-sheet inkjet printers in the above technical solutions, which affect the printing quality and efficiency.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: A printing drum flipping mechanism for a single-sheet inkjet printer, including a format adjustment member, an even-number multiple flipping drum, a flipping drum, a paper transfer drum, a cam adjustment unit, and a controller; The format adjustment member includes a guide rail, a screw rod, a servo motor, and a position sensor. The screw rod is driven by the servo motor and is used for horizontally adjusting the format of the printing paper; The even-number multiple flipping drum is composed of two symmetric rolling drums, and the rotation speed ratio of : is achieved through gear transmission, and is used for precisely flipping the paper during double-sided printing; The surface of the flipping drum is provided with grippers and vacuum adsorption holes, and a rotary air valve is configured inside, and is used for 180-degree flipping of a single sheet of paper; The paper transfer drum is coaxially installed with the flipping drum, and the surface is coated with an anti-slip coating, and is used for stably transferring the paper to the next printing unit; The cam adjustment unit includes a cam disc, a driven roller, a return spring, and a linear bearing, and is used to precisely control the opening and closing timing and pressure of the gripper. The controller receives the signals from the position sensors and coordinates the actions of the servo motor, the gear transmission, and the cam disc to achieve full-automatic operation.

[0006] As a preferred embodiment, the guide rail of the format adjustment member adopts a linear ball design, the screw is a precision ball screw, and the position sensor is an optical encoder, which can real-time feedback the positions of the even-multiple turning cylinder, the turning cylinder, and the sheet transfer cylinder to the controller to achieve closed-loop control.

[0007] The beneficial effects of adopting the above further scheme are as follows: The guide rail of the format adjustment member adopts a linear ball design, which improves the adjustment accuracy and stability. The screw is a precision ball screw, which ensures the accuracy of laterally adjusting the printing paper format. The position sensor is an optical encoder, which can real-time feedback the position information to the controller, achieving closed-loop control and further improving the stability and reliability of the system.

[0008] As a preferred embodiment, the gear transmission of the even-multiple turning cylinder includes a driving gear and a driven gear, the tooth number ratio of the two is 2:1, and the driven gear is connected to the controller through a phase synchronizer to ensure that the turning angle error is less than or equal to ±0.05 degrees.

[0009] The beneficial effects of adopting the above further scheme are as follows: The gear transmission of the even-multiple turning cylinder includes a driving gear and a driven gear, and the tooth number ratio is 2:1, which ensures the precise turning of the paper during double-sided printing. The driven gear is connected to the controller through a phase synchronizer, achieving precise control of the turning angle and improving the printing quality.

[0010] As a preferred embodiment, the vacuum adsorption holes of the turning cylinder are arranged in a spiral array, and the adsorption area accounts for 60%-70% of the surface area of the turning cylinder.

[0011] The beneficial effects of adopting the above further scheme are as follows: The vacuum adsorption holes of the turning cylinder are arranged in a spiral array, and the adsorption area accounts for 60%-70% of the surface area of the turning cylinder, effectively avoiding paper warping and ensuring the stability of the paper during the turning process.

[0012] As a preferred embodiment, the contour of the cam disc of the cam adjustment unit is a variable acceleration curve, the driven roller is linked with the gripper through a linear bearing, and the elastic coefficient of the return spring is 50N / mm - 80N / mm, ensuring that the gripper closes without delay at high speed.

[0013] The beneficial effects of adopting the above further solution are as follows: The cam profile of the cam adjustment unit is a variable acceleration curve, which optimizes the opening and closing timing and pressure of the gripper, improves the accuracy and stability of paper transfer. The elastic coefficient of the return spring is 50 N / mm - 80 N / mm, ensuring that the gripper closes without delay at high speeds, and further improving the printing efficiency and quality.

[0014] As a preferred embodiment, the anti-slip coating of the paper transfer cylinder is made of polyurethane material, with a friction coefficient of 0.3 - 0.5 and a coating thickness of 0.5 mm - 1.0 mm.

[0015] The beneficial effects of adopting the above further solution are as follows: The anti-slip coating of the paper transfer cylinder is made of polyurethane material, with a friction coefficient of 0.3 - 0.5 and a coating thickness of 0.5 mm - 1.0 mm, which adapts to papers of different grammages and improves the reliability and stability of paper transfer.

[0016] As a preferred embodiment, the controller is built-in with a PID algorithm, which dynamically adjusts the rotation speed of the servo motor and the phase angle of the cam disk according to the feedback signals of the position sensor and the phase synchronizer, so that the displacement error of the paper during transfer is less than or equal to ±0.1 mm.

[0017] The beneficial effects of adopting the above further solution are as follows: Through the PID algorithm built into the controller, precise control of the paper during transfer can be achieved.

[0018] As a preferred embodiment, the format adjustment member, the even-numbered flipping cylinder, and the cam adjustment unit are all connected by quick-release flanges, and the flange interfaces are provided with positioning pins and locking bolts.

[0019] The beneficial effects of adopting the above further solution are as follows: The format adjustment member, the even-numbered flipping cylinder, and the cam adjustment unit are all connected by quick-release flanges, which facilitates quick overall replacement or maintenance and improves the maintainability and flexibility of the equipment.

[0020] Compared with the prior art, the advantages and positive effects of the present invention are as follows: First, in the present invention, through the format adjustment component and precise control system, the printing precision and stability are greatly improved. The guide rail in the format adjustment component adopts a linear ball design, which, in combination with a precision ball screw and an optical encoder, realizes high-precision, fast, and stable lateral adjustment of the printing paper format. This design not only improves the adjustment precision but also significantly shortens the adjustment time, thereby enhancing the overall printing efficiency. Meanwhile, the application of the closed-loop control system realizes precise control of the printing process by real-time feedback of the position information of the double-sided reversing cylinder, reversing cylinder, and paper transfer cylinder to the controller, effectively reducing printing quality problems caused by mechanical errors. In addition, the design of the quick-release flange connection makes the replacement and maintenance of the format adjustment component, double-sided reversing cylinder, and cam adjustment unit more convenient and fast, further improving the reliability and maintainability of the equipment.

[0021] Second, in the present invention, through the combined application of the double-sided reversing cylinder and the reversing cylinder, the precision and efficiency of double-sided printing are significantly improved. The double-sided reversing cylinder realizes a speed ratio of 2:1 through precisely designed gear transmission, ensuring accurate flipping of the paper during double-sided printing. The driven gear is connected to the controller through a phase synchronizer to achieve precise control of the flipping angle, and the flipping angle error is less than or equal to ±0.05 degrees, which is of great significance in the field of high-precision printing. Meanwhile, the grippers and vacuum adsorption holes provided on the surface of the reversing cylinder, as well as the rotary air valve configured inside, ensure stable transmission and precise positioning of the paper during the flipping process, effectively avoiding paper offset and damage during flipping and further improving the printing quality.

[0022] Third, in the present invention, the polyurethane anti-slip coating applied on the surface of the paper transfer cylinder has a reasonable coating thickness and a moderate friction coefficient, effectively increasing the friction between the paper and the cylinder, preventing paper sliding and offset during transmission, and improving printing stability. In addition, the cam profile of the cam adjustment unit adopts a variable acceleration curve design. The driven roller is linked with the gripper through a linear bearing, and the reasonable setting of the elastic coefficient of the return spring ensures that the gripper closes without delay at high speed, improving the continuity and stability of paper transmission. The controller is built-in with a PID algorithm, which dynamically adjusts the rotation speed of the servo motor and the phase angle of the cam disk according to the feedback signals of the position sensor and the phase synchronizer, making the displacement error of the paper during transmission less than or equal to ±0.1 mm, further improving the printing precision and speed. Description of the Drawings

[0023] Figure 1 is the overall structural schematic diagram of the printing cylinder flipping mechanism of a single-sheet inkjet printer; Figure 2 is the overall structural schematic diagram of another axis side of the printing cylinder flipping mechanism of a single-sheet inkjet printer; Figure 3 It is a schematic diagram of the cam adjustment unit and related parts of the printing cylinder flipping mechanism of a single-sheet inkjet printer; Figure 4 It is a schematic diagram of the internal structure of the flipping cylinder and related parts of the printing cylinder flipping mechanism of a single-sheet inkjet printer; Figure 5 It is a partial schematic diagram of the reset spring and related parts of the printing cylinder flipping mechanism of a single-sheet inkjet printer.

[0024] Description of reference numerals: 1. Format adjustment component; 101. Guide rail; 102. Screw; 103. Servo motor; 104. Position sensor; 2. Even-numbered flipping cylinder; 201. Rolling cylinder; 202. Gear drive; 2021. Driving gear; 2022. Driven gear; 203. Phase synchronizer; 3. Flipping cylinder; 301. Paper gripper teeth; 302. Vacuum adsorption holes; 303. Rotary air valve; 4. Paper transfer cylinder; 401. Anti-slip coating; 5. Cam adjustment unit; 501. Cam disc; 502. Driven roller; 503. Reset spring; 504. Linear bearing; 6. Controller. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0026] As Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 shown, the present invention provides a technical solution: a printing cylinder flipping mechanism for a single-sheet inkjet printer, including a format adjustment component 1, an even-numbered flipping cylinder 2, a flipping cylinder 3, a paper transfer cylinder 4, a cam adjustment unit 5, and a controller 6; The format adjustment component 1 includes a guide rail 101, a screw 102, a servo motor 103, and a position sensor 104. The screw 102 is driven by the servo motor 103 and is used to horizontally adjust the format of the printed paper; The even-numbered flipping cylinder 2 is composed of two symmetric rolling cylinders 201, and realizes a speed ratio of 2:1 through a gear drive 202, and is used to accurately flip the paper during double-sided printing; The surface of the flipping cylinder 3 is provided with paper gripper teeth 301 and vacuum adsorption holes 302, and a rotary air valve 303 is configured inside, and is used for a 180-degree flip of a single sheet of paper; The paper transfer cylinder 4 is coaxially installed with the flipping cylinder 3, and its surface is coated with an anti-slip coating 401 for stably transferring the paper to the next printing unit; The cam adjustment unit 5 includes a cam disc 501, a driven roller 502, a return spring 503 and a linear bearing 504 for precisely controlling the opening and closing timing and pressure of the gripper jaws 301; The controller 6 receives the signals from the position sensor 104 and coordinates the actions of the servo motor 103, the gear drive 202 and the cam disc 501 to achieve full-automatic operation.

[0027] The guide rail 101 of the format adjustment member 1 adopts a linear ball design, the screw 102 is a precision ball screw, and the position sensor 104 is an optical encoder, which can real-time feedback the positions of the even-numbered flipping cylinder 2, the flipping cylinder 3 and the paper transfer cylinder 4 to the controller 6 to achieve closed-loop control.

[0028] The linear ball structure of the guide rail 101 is made of stainless steel, and the diameter tolerance of the balls is controlled within ±0.01 mm. With the C5 level precision of the precision ball screw 102, the repeat positioning accuracy of the lateral adjustment reaches ±0.02 mm; the position sensor 104 monitors the positions of the even-numbered flipping cylinder 2, the flipping cylinder 3 and the paper transfer cylinder 4 in real time, and its signals are transmitted to the controller 6 through the CAN bus, and the sampling frequency is not less than 1 kHz to ensure that the dynamic response time of the closed-loop control is less than 10 milliseconds.

[0029] The gear drive 202 of the even-numbered flipping cylinder 2 includes a driving gear 2021 and a driven gear 2022, and the tooth number ratio of the two is 2:1. And the driven gear 2022 is connected to the controller 6 through a phase synchronizer 203 to ensure that the flipping angle error is less than or equal to ±0.05 degrees.

[0030] The driving gear 2021 is treated by carburizing and quenching with 20CrMnTi; the phase synchronizer 203 includes a Hall sensor and an electromagnetic clutch. When the angle deviation is detected, the controller 6 triggers the clutch correction within 5 milliseconds, and the gear backlash is eliminated by a pre-tightening spring.

[0031] The vacuum adsorption holes 302 of the flipping cylinder 3 are distributed in a spiral array, and the adsorption area accounts for 60%-70% of the surface area of the flipping cylinder 3.

[0032] The spiral array of the vacuum adsorption holes 302 is distributed along the axial direction of the cylinder at an inclination angle of 15°; the air inlet channel of the rotary air valve 303 is of a double-chamber design, and the response time is less than or equal to 0.1 second to ensure that the paper has no slip during the flipping process.

[0033] The contour of the cam disk 501 of the cam adjustment unit 5 is a variable acceleration curve. The follower roller 502 is linked to the gripper 301 through a linear bearing 504. The elastic coefficient of the return spring 503 is 50 N / mm - 80 N / mm, ensuring that the gripper 301 closes without delay at high speeds.

[0034] The variable acceleration curve contour is composed of five spliced B-spline curves, with a maximum lift of 12 mm and continuous acceleration without mutation. The linear bearing 504 is made of graphite copper sleeve material, and the pre-compression stroke of the return spring 503 is 3 mm. At a working frequency of 8000 sheets / hour, the closing impact force fluctuation of the gripper 301 is less than or equal to 5%.

[0035] The anti-slip coating 401 of the paper transfer drum 4 is made of polyurethane material, with a friction coefficient of 0.3 - 0.5 and a coating thickness of 0.5 mm - 1.0 mm.

[0036] The polyurethane anti-slip coating 401 is formed by plasma spraying process, and the surface is laser etched to form a micro-texture with Ra6.3. The static friction coefficient measured under a normal pressure of 50 N is 0.42 ± 0.02, and the wear-resistant life exceeds 2 million cycles.

[0037] The controller 6 is built-in with a PID algorithm. According to the feedback signals of the position sensor 104 and the phase synchronizer 203, it dynamically adjusts the rotation speed of the servo motor 103 and the phase angle of the cam disk 501, so that the displacement error of the paper during transmission is less than or equal to ±0.1 mm.

[0038] The controller 6 synchronously controls the three-axis movement through the EtherCAT bus, uses feed-forward compensation technology to suppress the following error of the servo motor 103 within ±0.05 mm, and the adjustment resolution of the cam phase angle is 0.001°.

[0039] The format adjustment member 1, the even-numbered flip drum 2, and the cam adjustment unit 5 all adopt quick-release flange connections, and the flange interfaces are provided with positioning pins and locking bolts.

[0040] The positioning pin of the quick-release flange is a cemented carbide pin with a taper of 1:50; the locking bolt uses M12×1.25 fine thread, and the pre-tightening torque is 85 N·m ± 5%. The coaxiality of the flange docking is calibrated to within φ0.01 mm by a dial indicator, and the disassembly and assembly time does not exceed 3 minutes.

[0041] Working principle: The guide rail 101 in the format adjustment component 1 adopts a linear ball design. Cooperating with the precision ball screw 102 and driven by the servo motor 103, it precisely controls the lateral movement of the paper. The position sensor 104 real-time feeds back the position information to the controller 6 to achieve closed-loop control. Subsequently, the paper enters the inversion system composed of the even-number multiple inversion drum 2 and the inversion drum 3. The even-number multiple inversion drum 2 is driven by the 2:1 tooth number ratio of the driving gear 2021 and the driven gear 2022 to achieve precise double-sided inversion of the paper. The driven gear 2022 is connected to the controller 6 through the phase synchronizer 203 to ensure that the inversion angle error is extremely small. The gripper 301 on the surface of the inversion drum 3 precisely opens and closes under the control of the cam adjustment unit 5. The variable acceleration curve profile of the cam disk 501 cooperates with the driven roller 502, the return spring 503, and the linear bearing 504 to ensure that the gripper 301 closes without delay at high speed. At the same time, the vacuum adsorption holes 302 adsorb the paper to prevent deviation. After the paper is inverted, it is stably transmitted to the next printing unit by the paper transfer drum 4 coaxially installed with the inversion drum 3. The polyurethane anti-slip coating 401 on the surface of the paper transfer drum 4 effectively prevents the paper from sliding. During the whole process, the controller 6 has a built-in PID algorithm, which dynamically adjusts the servo motor 103 and the cam disk 501 according to the feedback signal to ensure that the displacement error during the paper transfer process is extremely small, so as to achieve high-precision and high-efficiency printing operations.

[0042] The above is only a preferred embodiment of the present invention, and it is not a limitation of the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. The printing cylinder flipping mechanism of the sheet-fed inkjet printer is characterized by: It comprises a format adjustment component (1), an even-numbered reversing roller (2), a reversing roller (3), a paper transfer roller (4), a cam adjustment unit (5) and a controller (6); The width adjustment component (1) comprises a guide rail (101), a screw rod (102), a servo motor (103) and a position sensor (104); the screw rod (102) is driven by the servo motor (103) and is used to adjust the width of the printed paper in the transverse direction; The even-numbered reversing roller (2) is composed of two symmetrical rolling rollers (201), which achieve a rotation speed ratio of 2:1 through gear transmission (202) and are used to accurately reverse the paper during double-sided printing; The surface of the turning roller (3) is provided with paper biting teeth (301) and vacuum adsorption holes (302), and a rotary air valve (303) is arranged inside to turn a single sheet of paper 180 degrees; The paper transfer roller (4) is coaxially mounted with the turning roller (3), and has a surface coated with an anti-slip coating (401) for stably transferring paper to the next printing unit; The cam adjustment unit (5) comprises a cam plate (501), a driven roller (502), a return spring (503) and a linear bearing (504), and is used to accurately control the opening and closing timing and pressure of the bite teeth (301); The controller (6) receives a signal from the position sensor (104) and coordinates the actions of the servo motor (103), the gear transmission (202) and the cam plate (501) to achieve fully automatic operation.

2. The printing cylinder turning mechanism of a sheet-fed inkjet printer according to claim 1 is characterized in that: The guide rail (101) of the width adjustment component (1) adopts a linear ball bearing design, the screw (102) is a precision ball bearing screw, and the position sensor (104) is a photoelectric encoder, which feeds back the positions of the even-numbered turning roller (2), the turning roller (3) and the paper transfer roller (4) to the controller (6) in real time, thereby realizing closed-loop control.

3. The printing cylinder turning mechanism of a sheet-fed inkjet printer according to claim 1 is characterized in that: The gear transmission (202) of the even-number flipping drum (2) comprises a driving gear (2021) and a driven gear (2022), the gear ratio of the two being 2:1, and the driven gear (2022) is connected to the controller (6) via a phase synchronizer (203), ensuring that the flipping angle error is less than or equal to ±0.05 degrees.

4. The printing cylinder turning mechanism of a sheet-fed inkjet printer according to claim 1 is characterized in that: The vacuum adsorption holes (302) of the turning roller (3) are distributed in a spiral array, and the adsorption area accounts for 60%-70% of the surface area of ​​the turning roller (3).

5. The printing cylinder turning mechanism of a sheet-fed inkjet printer according to claim 1 is characterized in that: The profile of the cam disc (501) of the cam adjustment unit (5) is a variable acceleration curve, the driven roller (502) is linked to the paper biting tooth (301) via a linear bearing (504), and the elastic coefficient of the return spring (503) is 50N / mm-80N / mm, ensuring that the paper biting tooth (301) closes without delay at high speed.

6. The printing cylinder turning mechanism of a sheet-fed inkjet printer according to claim 1 is characterized in that: The anti-slip coating (401) of the paper transfer roller (4) is made of polyurethane material, has a friction coefficient of 0.3-0.5, and a coating thickness of 0.5 mm-1.0 mm.

7. The printing cylinder turning mechanism of a sheet-fed inkjet printer according to claim 1, characterized in that: The controller (6) has a built-in PID algorithm, and dynamically adjusts the rotation speed of the servo motor (103) and the phase angle of the cam plate (501) according to feedback signals from the position sensor (104) and the phase synchronizer (203), so that the displacement error of the paper during the transmission process is less than or equal to ±0.1 mm.

8. The printing cylinder turning mechanism of a sheet-fed inkjet printer according to claim 1 is characterized in that: The width adjustment component (1), the even-number turning roller (2) and the cam adjustment unit (5) are all connected by a quick-release flange, and the flange interface is provided with a positioning pin and a locking bolt.

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