Tension control method for a tension control system of a paper feeding section of an offset printing press

Abstract

The present invention discloses a tension control method for a tension control system in the paper feed section of an offset printing press. The system comprises a driving roller, a platen roller, a swing roller, a speed detection roller, a pressure roller, a speed detection mechanism, a light tension detection feedback mechanism, a high tension detection feedback mechanism, and a motion controller. The driving roller is driven by a servo motor; the platen roller is driven by two platen roller clutch cylinders, the air circuits of which are controlled by a platen roller cylinder solenoid valve; the speed detection mechanism includes a speed encoder mounted on the speed detection roller; the light tension detection feedback mechanism includes a swing roller cylinder proportional valve and an angle detection sensor that control the two swing roller drive cylinders; and the high tension detection feedback mechanism includes two pressure sensors mounted on the pressure roller. The motion controller is signal-connected to the servo driver, angle detection sensor, speed encoder, swing roller cylinder proportional valve, pressure sensor, and platen roller cylinder solenoid valve. The present invention can stabilize the tension of a paper strip within a certain range.

Description

Technical Field

[0001] The invention relates to a tension control method of a tension control system of a paper feeding part of an offset printing machine. Background Art

[0002] The web of a web offset printing press must maintain a certain tension. Excessive web tension, failure of the tension control system to adjust promptly when the printing speed fluctuates significantly, or excessive tension fluctuations during tension adjustment can all lead to longitudinal misregistration during printing. Therefore, timely and stable tension adjustment is essential. Excessive web tension increases the tensile stress of the web. If the tensile stress exceeds the allowable tensile stress of the web, the web will break. Unstable web tension can cause jitter, resulting in misregistration and ghosting. In newspaper printing presses, unstable tension can also cause problems such as uneven folding lengths. Therefore, printing presses typically feature a paper feed section with a tension control system on the paper feed side of the printing unit. First, the web tension is set. If the web tension is not appropriate or fluctuates, the tension control system must be used to adjust it promptly. Traditional tension adjustment methods often use a DC motor or a variable-frequency AC motor to drive the active roller. This drive system results in a narrow tension adjustment range, poor adjustment accuracy, large tension control fluctuations, and low control stability. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a tension adjustment system for the paper feeding part of an offset printing machine, which can keep the tension of various paper tapes entering the printing unit stable within a certain range, improve the printing overprint accuracy, and thus improve the quality of the printed product.

[0004] The object of the present invention is achieved as follows: a tension control system for the paper feeding section of an offset printing press, which is arranged between the wall panels on both sides of the paper feeding section and includes first to sixth paper feed rollers, a driving roller, a pressing roller, a swing roller, a speed detection roller, a pressure roller, a driving roller driving mechanism, a speed detection mechanism, a light tension detection feedback mechanism, a high tension detection feedback mechanism and a motion controller; wherein,

[0005] The active roller is tangentially arranged above the paper pressing roller;

[0006] The paper tape first sticks to the lower surface of the first paper roller and enters the paper feeding section, then goes around the second paper roller counterclockwise, then enters between the main roller and the paper pressing roller, then goes around the main roller clockwise, then goes around the swing roller counterclockwise, goes around the speed detection roller clockwise, goes around the third paper roller to the sixth paper roller clockwise, and finally goes around the pressure roller counterclockwise before exiting the paper feeding section and entering the printing unit.

[0007] The active roller driving mechanism includes a servo motor provided on the driving side shaft head of the active roller and a servo driver connected to the servo motor signal;

[0008] The shaft heads at both ends of the paper pressing roller are respectively connected to a paper pressing roller clutch cylinder, and the air paths of the two paper pressing roller clutch cylinders are both provided with paper pressing roller cylinder solenoid valves;

[0009] The speed detection mechanism includes a speed encoder mounted on the shaft head of the speed detection roller;

[0010] The light tension detection feedback mechanism includes a swing roller rotating shaft, two swing arms, two swing roller driving cylinders and an angle detection sensor; the swing roller rotating shaft is rotatably connected between the wall panels on both sides; the upper ends of the two swing arms are fixedly sleeved on the two ends of the swing roller rotating shaft in a one-to-one manner; the two end shaft heads of the swing roller are installed in the lower parts of the two swing arms in a one-to-one manner; the two swing roller driving cylinders are hinged on the inner side surfaces of the wall panels on both sides in a one-to-one manner, and the ends of the piston rods of the two swing roller driving cylinders are connected to the lower parts of the two swing arms in a one-to-one manner, and the movement direction of the piston rods of the two swing roller driving cylinders is opposite to the direction of the pulling force of the paper tape on the swing roller, and the air paths of the two swing roller driving cylinders are provided with swing roller cylinder proportional valves; the angle detection sensor is installed on the end heads of the swing roller rotating shaft;

[0011] The high tension detection feedback mechanism includes two pressure sensors mounted on the shaft heads at both ends of the pressure roller in a one-to-one correspondence;

[0012] The motion controller is respectively connected to the servo driver, the angle detection sensor, the speed encoder, the swing roller cylinder proportional valve, the pressure sensor, and the paper pressing roller cylinder electromagnetic valve signal.

[0013] In the above-mentioned tension control system of the paper feeding section of the offset printing press, the pressure sensor is connected to the motion controller signal through a signal amplifier.

[0014] In the above-mentioned tension control system of the paper feeding section of the offset printing machine, the motion controller is further connected to the control panel via a signal line.

[0015] The above-mentioned tension control system of the paper feeding section of the offset printing machine, wherein the first paper feeding roller is arranged at the paper inlet of the paper feeding section; the pressure roller is arranged above and behind the first paper feeding roller; the second paper feeding roller is arranged above and behind the pressure roller; the swing roller is arranged above and behind the active roller; the speed detection roller is arranged above and in front of the swing roller; the third paper feeding roller is arranged directly above the speed detection roller; the fourth paper feeding roller is arranged directly behind the third paper feeding roller; the fifth paper feeding roller is arranged directly below the fourth paper feeding roller; the sixth paper feeding roller is arranged directly below the fifth paper feeding roller; the pressure roller is arranged at the paper outlet of the paper feeding section and is located below and in front of the sixth paper feeding roller, and the pressure roller is located directly behind the first paper feeding roller.

[0016] In the above-mentioned tension control system of the paper feeding section of the offset printing press, the light tension detection feedback mechanism further includes two pairs of limit blocks fixed on the inner side surfaces of the two side wall panels in a one-to-one correspondence and located on both sides of the middle part of the two swing arms.

[0017] The tension adjustment system of the paper feeding section of the offset printing press of the present invention has the following characteristics: a servo motor is used to drive the active roller, and a light tension detection feedback mechanism and a high tension detection feedback mechanism are provided. The light tension detection feedback mechanism or the high tension detection feedback mechanism can be selected according to the type of paper tape, and the tension of different types of paper tapes can be detected and controlled in real time, so that the tension of various types of paper tapes is stabilized within a certain range before entering the printing unit, thereby ensuring accurate overprinting entering the printing, greatly improving the quality of the printing press, and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a tension control system of a paper feeding section of an offset printing press of the present invention;

[0019] Figure 2 This is a control principle diagram of the tension control system of the paper feeding section of the offset printing press of the present invention;

[0020] Figure 3 It is a schematic diagram of the operation of the active roller in the tension control system of the present invention;

[0021] Figure 4 It is a schematic diagram of the operation of the swing roller in the tension control system of the present invention;

[0022] Figure 5 It is a working schematic diagram of the pressure roller in the tension control system of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] See also Figures 1 to 5 The tension control system of the paper feeding section of the offset printing press of the present invention is arranged between the driving side wall plate and the operating side wall plate of the paper feeding section and includes first to sixth paper feeding rollers 11a to 11f, an active roller 2, a pressure roller 3, a swing roller 4, a speed detection roller 5, a pressure roller 6, an active roller driving mechanism, a speed detection mechanism, a light tension detection feedback mechanism, a high tension detection feedback mechanism and a motion controller.

[0025] The first paper-passing roller 11a is arranged at the paper inlet of the paper-feeding section; the pressing roller 3 is arranged above and behind the first paper-passing roller 11a; the second paper-passing roller 11b is arranged above and behind the pressing roller 3; the active roller 2 is arranged tangentially above the pressing roller 3; the swing roller 4 is arranged above and behind the active roller 2; the speed detection roller 5 is arranged above and in front of the swing roller 4; the third paper-passing roller 11c is arranged directly above the speed detection roller 5; the fourth paper-passing roller 11d is arranged directly behind the third paper-passing roller 11c; the fifth paper-passing roller 11e is arranged directly below the fourth paper-passing roller 11d; the sixth paper-passing roller 11f is arranged directly below the fifth paper-passing roller 11e; the pressure roller 6 is arranged at the paper outlet of the paper-feeding section and is located below and in front of the sixth paper-passing roller 11e, and the pressure roller 6 is located directly behind the first paper-passing roller 11a.

[0026] The paper tape 100 first enters the paper feeding section along the lower surface of the first paper feeding roller 11a, then goes around the second paper feeding roller 11b counterclockwise, then enters between the active roller 2 and the paper pressing roller 3, then goes around the active roller 2 clockwise, then goes around the swing roller 4 counterclockwise, goes around the speed detection roller 5 clockwise, goes around the third paper feeding roller 11c to the sixth paper feeding roller 11f clockwise, and finally goes around the pressure roller 6 counterclockwise before exiting the paper feeding section and entering the printing unit.

[0027] The active roller driving mechanism includes a servo motor 2A provided on a driving-side shaft head of the active roller 2 and a servo driver 20 connected to the servo motor 2A by signal.

[0028] The shaft heads at both ends of the paper pressing roller 3 are respectively connected to a paper pressing roller clutch cylinder 3A, and the air paths of the two paper pressing roller clutch cylinders 3A are both provided with paper pressing roller cylinder solenoid valves 30 .

[0029] The speed detection mechanism includes a speed encoder 50 mounted on the shaft head of the speed detection roller 5 .

[0030] The light tension detection feedback mechanism includes a swing roller rotating shaft 4A, two swing arms 4B, two swing roller driving cylinders 4C, an angle detection sensor 40 and two pairs of limit blocks 4D; wherein, the swing roller rotating shaft 4A is rotatably connected between the driving side wall panel and the operating side wall panel; the upper ends of the two swing arms 4B are fixedly sleeved on the two ends of the swing roller rotating shaft 4A in a one-to-one correspondence; the two end shaft heads of the swing roller 4 are mounted on the lower parts of the two swing arms 4B in a one-to-one correspondence; the two swing roller driving cylinders 4C are hinged on the inner side surfaces of the driving side wall panel and the inner side surfaces of the operating side wall panel in a one-to-one correspondence. The ends of the piston rods of the swing roller driving cylinders 4C are connected to the lower parts of the two swing arms 4B in a one-to-one correspondence, and the movement direction of the piston rods of the two swing roller driving cylinders 4C is opposite to the direction of the pulling force exerted by the paper tape 100 on the swing roller 4. The air paths of the two swing roller driving cylinders 4C are each provided with a swing roller cylinder proportional valve 41; the angle detection sensor 40 is installed on the end of the swing roller rotating shaft 4A; two pairs of limit blocks 4D are installed in a one-to-one correspondence on the inner side surfaces of the driving side wall panel and the inner side surfaces of the operating side wall panel and are located in a one-to-one correspondence on both sides of the middle part of the two swing arms 4B.

[0031] The high tension detection feedback mechanism includes two pressure sensors 60 mounted on the shaft heads at both ends of the pressure roller 6 in a one-to-one correspondence.

[0032] The motion controller 70 is connected to a control panel 700 via signal lines. This control panel 700 is located on the outside of the operating side wall panel. The motion controller 70 is connected to the servo driver 20, the angle detection sensor 40, the swing roller cylinder proportional valve 41, the speed encoder 50, the signal amplifier 61, and the paper pressing roller cylinder solenoid valve 30. The signal amplifier 61 is connected to the pressure sensor 60. After receiving signals from the speed encoder 50, the motion controller 70 controls the speed of the servo motor 2A via the servo driver 20. After receiving signals from the angle detection sensor 40, the motion controller 70 controls the extension and contraction of the piston rod of the swing roller drive cylinder 4C via the swing roller cylinder proportional valve 41, thereby adjusting the radial tension of the paper tape 100 on the swing roller 4. After receiving signals from the pressure sensor 60, the motion controller 70 controls the speed of the servo motor 2A via the servo driver 20.

[0033] The tension control system for the paper feed section of an offset printing press of the present invention adjusts the tension of the paper strip 100 through a drive roller drive mechanism. During operation, the motion controller 70 first controls the solenoid valve 30 of the platen roller cylinder to open the air path of the platen roller clutch cylinder 3A, extending the piston rod of the platen roller clutch cylinder 3A. This in turn drives the platen roller 3 to press the paper strip 100 against the drive roller 2. The motion controller 70 then drives the servo motor 2A via the servo driver 20 to rotate, allowing the paper strip 10 to travel within the paper feed section. By adjusting the rotational speed of the drive roller 2, a speed difference is created between the drive roller 2 and the print cylinder 200 of the subsequent printing unit, exerting a forward or backward force on the paper strip 100 and thereby varying the tension of the paper strip 100. When the surface linear velocity of the active roller 2 is greater than the surface linear velocity of the printing cylinder 200, the tension of the paper tape 100 decreases. When the surface linear velocity of the active roller 2 is less than the surface linear velocity of the printing cylinder 200, the tension of the paper tape 100 increases, thereby adjusting the tension of the paper tape 100 entering the printing unit. The speed encoder 50 installed on the shaft head of the speed detection roller 5 detects the rotation speed of the speed detection roller 5 and provides it to the motion controller 70. The motion controller 70 converts the current linear velocity of the paper tape 100 and uses this as the reference speed to control the rotation speed of the servo motor 2A through the servo driver 20, so that the surface linear velocity of the active roller 2 is synchronized with the surface linear velocity of the cylinder 200 (see Figure 3 ).

[0034] When the tension of the paper tape 100 fluctuates, feedback is provided to the motion controller 70 via the light tension detection feedback mechanism or the high tension detection feedback mechanism. The motion controller 70 then controls the rotation speed of the active roller 2 via the active roller drive mechanism, automatically and stably adjusting the tension. When the paper tape 100 is thin (such as film or cellophane), the light tension detection feedback mechanism is selected for stable tension adjustment via the control panel 700. When the paper tape 100 is thick (such as coated paper or corrugated paper), the high tension detection feedback mechanism is selected for stable tension adjustment via the control panel 700. Based on the actual tension of the paper tape 100 provided by the light tension detection feedback mechanism or the high tension detection feedback mechanism, the motion controller 70 compares the actual tension with the set value and, using a PID control algorithm, adjusts the rotation speed of the active roller 2, thereby adjusting the tension of the paper tape 100 to maintain it within the allowable fluctuation range of the set value.

[0035] When the paper tape 100 is of a thin type, the set tension value of the paper tape 100 is first input on the control panel 700. The motion controller 70 converts the set tension value into an analog signal to control the air pressure value of the swing roller cylinder proportional valve 41 to supply air to the swing roller drive cylinder 4C, so that the swing roller 4 is subjected to the radial thrust generated by the piston rod of the swing roller drive cylinder 4C. The radial thrust is opposite to the direction of the pulling force generated by the paper tape 100 wrapped around the swing roller 4 on the swing roller 4, and offsets each other, so that the swing roller 4 is in a central position based on the swing fulcrum of the two swing arms 4B. When the pulling force generated by the paper tape 100 on the swing roller 4 is greater than or less than the radial thrust of the swing roller drive cylinder 4C on the swing roller 4, the swing roller 4 will deflect. The angle detection sensor 40 installed on the shaft end of the swing roller rotating shaft 4A converts the deflection angle into an analog signal and feeds it back to the motion controller 70. The motion controller 70 uses the PID control algorithm to correct the speed of the servo motor 2A through the servo driver 20, that is, to correct the speed of the active roller 2 to adjust the tension of the paper tape 100, so that the pulling force generated by the paper tape 100 on the swing roller 4 and the radial thrust generated by the swing roller drive cylinder 4C on the swing roller 4 are restored to balance. Since the radial thrust generated by the swing roller drive cylinder 4C is a constant force controlled by the swing roller cylinder proportional valve 41, it is used as a reference to balance the tension of the paper tape 100 (see Figure 4 ). The light tension detection feedback mechanism has sensitive information feedback.

[0036] When the paper tape 100 is of a thick type, the set tension value of the paper tape 100 is first input on the control panel 700, and the motion controller 70 converts the set tension value into an analog quantity. When the paper tape 100 moves, it will generate a radial pulling force on the pressure roller 6. This pulling force is linearly proportional to the tension of the paper tape 100. The two pressure sensors 60 installed on the pressure roller 6 convert the radial pulling force generated by the paper tape 100 on the pressure roller 6 into an analog signal and then feed it back to the motion controller 70 through the signal amplifier 61. The motion controller 70 compares the signal with the set tension value, and then, after the PID control algorithm, corrects the speed of the servo motor 2A through the servo driver 20, that is, corrects the speed of the active roller 2 to adjust the tension of the paper tape 100, so that the tension of the paper tape 100 remains stable (see Figure 5 The high tension detection feedback mechanism provides stable tension detection feedback for thick and heavy paper tapes.

[0037] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A tension control method for a tension control system of a paper feed section of an offset printing press, wherein the tension control system is disposed between two side wall panels of the paper feed section and comprises first to sixth paper feed rollers, a driving roller, a pressing roller, a swing roller, a speed detection roller, a pressure roller, a driving roller driving mechanism, a speed detection mechanism, a light tension detection feedback mechanism, a high tension detection feedback mechanism, and a motion controller; characterized in that: The active roller is tangentially arranged above the paper pressing roller; The paper tape first sticks to the lower surface of the first paper roller and enters the paper feeding section, then goes around the second paper roller counterclockwise, then enters between the main roller and the paper pressing roller, then goes around the main roller clockwise, then goes around the swing roller counterclockwise, goes around the speed detection roller clockwise, goes around the third paper roller to the sixth paper roller clockwise, and finally goes around the pressure roller counterclockwise before exiting the paper feeding section and entering the printing unit. The active roller driving mechanism includes a servo motor provided on the driving side shaft head of the active roller and a servo driver connected to the servo motor signal; The shaft heads at both ends of the paper pressing roller are respectively connected to a paper pressing roller clutch cylinder, and the air paths of the two paper pressing roller clutch cylinders are both provided with paper pressing roller cylinder solenoid valves; The speed detection mechanism includes a speed encoder mounted on the shaft head of the speed detection roller; The light tension detection feedback mechanism includes a swing roller rotating shaft, two swing arms, two swing roller driving cylinders, an angle detection sensor and two pairs of limit blocks; the swing roller rotating shaft is rotatably connected between the wall panels on both sides; the upper ends of the two swing arms are fixedly sleeved on the two ends of the swing roller rotating shaft in a one-to-one manner; the two end shaft heads of the swing roller are installed in the lower parts of the two swing arms in a one-to-one manner; the two swing roller driving cylinders are hinged on the inner side surfaces of the wall panels on both sides in a one-to-one manner, and the ends of the piston rods of the two swing roller driving cylinders are connected to the lower parts of the two swing arms in a one-to-one manner, and the movement direction of the piston rods of the two swing roller driving cylinders is opposite to the direction of the pulling force of the paper tape on the swing roller, and the air paths of the two swing roller driving cylinders are provided with swing roller cylinder proportional valves; the angle detection sensor is installed on the end heads of the swing roller rotating shaft; two pairs of limit blocks are fixed on the inner side surfaces of the wall panels on both sides in a one-to-one manner and are located on both sides of the middle of the two swing arms; The high tension detection feedback mechanism includes two pressure sensors mounted on the shaft heads at both ends of the pressure roller in a one-to-one correspondence; The motion controller is respectively connected to the servo driver, angle detection sensor, speed encoder, swing roller cylinder proportional valve, pressure sensor, and paper pressing roller cylinder solenoid valve; the pressure sensor is connected to the motion controller signal through a signal amplifier; the motion controller is connected to the control panel through a signal line; wherein, When the paper tape is of a light and thin type, the control panel selects the light tension detection feedback mechanism to be used for stable tension adjustment; when the paper tape is of a thick and heavy type, the control panel selects the high tension detection feedback mechanism to be used for stable tension adjustment; the motion controller compares the actual tension value of the paper tape provided by the light tension detection feedback mechanism or the high tension detection feedback mechanism with the set value, and uses the PID control algorithm to correct the rotation speed of the active roller, thereby adjusting the tension of the paper tape.

2. The tension control method of the tension control system of the paper feeding section of the offset printing press according to claim 1, characterized in that: The first paper feed roller is arranged at the paper inlet of the paper feeding unit; the pressing roller is arranged above and behind the first paper feed roller; the second paper feed roller is arranged above and behind the pressing roller; the swing roller is arranged above and behind the driving roller; the speed detection roller is arranged above and in front of the swing roller; and the third paper feed roller is arranged directly above the speed detection roller. The fourth paper-passing roller is arranged directly behind the third paper-passing roller; the fifth paper-passing roller is arranged directly below the fourth paper-passing roller; the sixth paper-passing roller is arranged directly below the fifth paper-passing roller; the pressure roller is arranged at the paper outlet of the paper feeding part and is located in front of and below the sixth paper-passing roller, and the pressure roller is located directly behind the first paper-passing roller.

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